CN114136055B - Device and method for recycling argon and methane from tail gas of synthetic ammonia - Google Patents
Device and method for recycling argon and methane from tail gas of synthetic ammonia Download PDFInfo
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- CN114136055B CN114136055B CN202111444831.4A CN202111444831A CN114136055B CN 114136055 B CN114136055 B CN 114136055B CN 202111444831 A CN202111444831 A CN 202111444831A CN 114136055 B CN114136055 B CN 114136055B
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- nitrogen
- methane
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- tail gas
- rich
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- 239000007789 gas Substances 0.000 title claims abstract description 370
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 338
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 322
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 title claims abstract description 276
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 169
- 229910052786 argon Inorganic materials 0.000 title claims abstract description 138
- 238000000034 method Methods 0.000 title claims abstract description 45
- 238000004064 recycling Methods 0.000 title abstract description 18
- JVFDADFMKQKAHW-UHFFFAOYSA-N C.[N] Chemical compound C.[N] JVFDADFMKQKAHW-UHFFFAOYSA-N 0.000 claims abstract description 401
- 238000006356 dehydrogenation reaction Methods 0.000 claims abstract description 98
- 238000003786 synthesis reaction Methods 0.000 claims abstract description 79
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 78
- 238000005057 refrigeration Methods 0.000 claims abstract description 43
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 398
- 229910052757 nitrogen Inorganic materials 0.000 claims description 195
- 239000007788 liquid Substances 0.000 claims description 142
- 239000001257 hydrogen Substances 0.000 claims description 111
- 229910052739 hydrogen Inorganic materials 0.000 claims description 111
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 106
- 238000010992 reflux Methods 0.000 claims description 46
- 239000002826 coolant Substances 0.000 claims description 15
- 238000001704 evaporation Methods 0.000 claims description 15
- 230000008020 evaporation Effects 0.000 claims description 15
- 239000007791 liquid phase Substances 0.000 claims description 14
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 claims description 10
- 238000001816 cooling Methods 0.000 claims description 9
- 238000000926 separation method Methods 0.000 claims description 9
- 239000012071 phase Substances 0.000 claims description 8
- 230000006835 compression Effects 0.000 claims description 6
- 238000007906 compression Methods 0.000 claims description 6
- 150000002431 hydrogen Chemical class 0.000 claims description 6
- 239000001294 propane Substances 0.000 claims description 5
- 238000009413 insulation Methods 0.000 claims description 3
- 208000037157 Azotemia Diseases 0.000 claims 9
- 238000005265 energy consumption Methods 0.000 abstract description 26
- 239000003507 refrigerant Substances 0.000 abstract description 8
- 238000012423 maintenance Methods 0.000 abstract description 6
- AWAUBADRMJIRAK-UHFFFAOYSA-N azane;methane Chemical compound C.N AWAUBADRMJIRAK-UHFFFAOYSA-N 0.000 description 3
- 230000002194 synthesizing effect Effects 0.000 description 3
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 101710141078 Ammonium transporter Proteins 0.000 description 1
- 230000009615 deamination Effects 0.000 description 1
- 238000006481 deamination reaction Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000002737 fuel gas Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- -1 methyl nitride Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0204—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the feed stream
- F25J3/0219—Refinery gas, cracking gas, coke oven gas, gaseous mixtures containing aliphatic unsaturated CnHm or gaseous mixtures of undefined nature
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
- F25J3/0233—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 1 carbon atom or more
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
- F25J3/0252—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of hydrogen
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
- F25J3/0257—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of nitrogen
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
- F25J3/028—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of noble gases
- F25J3/0285—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of noble gases of argon
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J5/00—Arrangements of cold exchangers or cold accumulators in separation or liquefaction plants
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/50—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/72—Refluxing the column with at least a part of the totally condensed overhead gas
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2210/00—Processes characterised by the type or other details of the feed stream
- F25J2210/20—H2/N2 mixture, i.e. synthesis gas for or purge gas from ammonia synthesis
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2215/00—Processes characterised by the type or other details of the product stream
- F25J2215/04—Recovery of liquid products
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2270/00—Refrigeration techniques used
- F25J2270/12—External refrigeration with liquid vaporising loop
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2270/00—Refrigeration techniques used
- F25J2270/60—Closed external refrigeration cycle with single component refrigerant [SCR], e.g. C1-, C2- or C3-hydrocarbons
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2270/00—Refrigeration techniques used
- F25J2270/66—Closed external refrigeration cycle with multi component refrigerant [MCR], e.g. mixture of hydrocarbons
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2270/00—Refrigeration techniques used
- F25J2270/90—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
- F25J2290/34—Details about subcooling of liquids
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Separation By Low-Temperature Treatments (AREA)
Abstract
The invention discloses a device and a method for recycling argon and methane from synthesis ammonia tail gas, which solve the technical problems of high energy consumption, complex flow, refrigerant proportioning and control existing in the prior art for recycling the argon and the methane from the synthesis ammonia tail gas. The device comprises a heat exchanger, a dehydrogenation tower, a demethanizer, a denitrification tower and a precooler; the upper part of the dehydrogenation tower is provided with a dehydrogenation tower top condenser; the upper part and the lower part of the demethanizer are respectively provided with a demethanizer top condenser and a demethanizer bottom evaporator; the upper part and the lower part of the denitrification tower are respectively provided with a denitrification tower top condenser and a denitrification tower bottom evaporator. The invention recovers argon and methane from the synthetic ammonia tail gas by the refrigeration cycle of the nitrogen methane with precooling to provide cold energy, has low energy consumption, simple proportioning of the nitrogen methane, easy operation, lower investment and operation cost, mature and easy control of the precooling machine set process and less maintenance.
Description
Technical Field
The invention relates to the technical field of argon extraction in synthesis ammonia tail gas, in particular to a device and a method for recycling argon and methane from synthesis ammonia tail gas by using a precooled nitrogen methane refrigeration cycle.
Background
The tail gas of synthetic ammonia is used as purge gas in synthetic ammonia industry, after purification treatment such as deamination and dehydration, the main components are nitrogen, hydrogen, methane and argon, the components change along with the process conditions, wherein the general volume ratio is as follows: argon 4-12%, methane 6-35%.
Argon is a rare gas widely applied at present, can be used as the main filling gas of an incandescent lamp, is used as a protective gas for welding and cutting metals, can also be used for extinguishing a fire and replacing air to provide an argon sealing environment to avoid the oxidation of articles, and has higher economic value.
The existing technology recovers argon and LNG from the synthesis ammonia tail gas, but when the content of methane in the synthesis ammonia tail gas is low or the methane does not need to be liquefied into LNG for recovery, the methane can be subjected to gaseous recovery to be used as fuel gas of the upstream industry.
The existing refrigeration technology for recovering argon and methane from the tail gas of synthetic ammonia mainly comprises nitrogen double-expansion refrigeration, mixed refrigerant and nitrogen double refrigeration.
Nitrogen double expansion refrigeration: the refrigeration flow moving equipment comprises a low-pressure circulating nitrogen compressor, a medium-pressure circulating nitrogen compressor, a low-temperature supercharging turbine expander and a high-temperature supercharging turbine expander, and is more in equipment moving equipment, complex in control, large in maintenance workload, longer in period and lower in energy consumption by about 5% than that of single nitrogen expansion refrigeration.
Mixing the refrigerant and nitrogen for double refrigeration: the refrigeration process moving equipment comprises a mixed refrigerant circulating compressor and a medium-pressure circulating nitrogen compressor, and the moving equipment is fewer, but the mixed refrigerant is complex in proportion and complex in control.
Disclosure of Invention
The invention aims to provide a device and a method for recycling argon and methane from synthesis ammonia tail gas by using precooled nitrogen-methane refrigeration cycle, which are used for solving the technical problems of high energy consumption, complex flow, refrigerant proportioning and control existing in the prior art for recycling the argon and the methane from the synthesis ammonia tail gas.
In order to achieve the above purpose, the present invention provides the following technical solutions:
the invention provides a device for recycling argon and methane from synthesis ammonia tail gas by precooling nitrogen methane refrigeration cycle, which comprises a heat exchanger, a subcooler, a dehydrogenation tower, a demethanizer, a denitrification tower and a precooler; wherein,
The upper part of the dehydrogenation tower is provided with a dehydrogenation tower top condenser;
The upper part and the lower part of the demethanizer are respectively provided with a demethanizer top condenser and a demethanizer bottom evaporator;
the upper part and the lower part of the denitrification tower are respectively provided with a denitrification tower top condenser and a denitrification tower bottom evaporator;
The heat exchanger is internally provided with a synthetic ammonia tail gas channel I, a synthetic ammonia tail gas channel II, a hydrogen-rich tail gas channel I, a methane-rich gas channel I, a nitrogen-rich tail gas channel I, a nitrogen methane forward flow channel II, a nitrogen methane forward flow channel III and a nitrogen methane return flow channel I;
the subcooler is internally provided with a hydrogen-rich tail gas channel II, a nitrogen methane backflow channel II, a nitrogen methane forward flow channel IV, a liquid argon channel and a nitrogen-rich tail gas channel II;
a hydrogen-rich channel I and a methyl nitride channel I are arranged in the dehydrogenation tower top condenser;
a nitrogen-rich channel I and a nitrogen-methane channel II are arranged in the demethanizer top condenser;
a nitrogen-rich channel II and a nitrogen methane channel III are arranged in the denitrification tower top condenser;
A synthetic ammonia tail gas channel III, a nitrogen methane positive flow channel V and a precooling medium channel are arranged in the precooler;
The heat exchanger is connected with a synthetic ammonia tail gas inlet pipe, a hydrogen-rich tail gas outlet pipe, a methane outlet pipe, a nitrogen-rich tail gas outlet pipe and a nitrogen-methane circulating air inlet device; the subcooler is connected with a liquid argon outlet pipe;
The nitrogen-methane circulation air inlet device comprises a nitrogen-methane compressor, wherein a nitrogen inlet pipe is connected to an inlet of the nitrogen-methane compressor, a nitrogen inlet pipe and a methane inlet pipe are connected to the nitrogen inlet pipe, a nitrogen outlet pipe is connected to an outlet of the nitrogen-methane compressor, an outlet of the nitrogen outlet pipe is connected with an inlet of a nitrogen-methane forward flow channel I, an outlet of the nitrogen-methane forward flow channel I is connected with an inlet of a nitrogen-methane forward flow channel V, an outlet of the nitrogen-methane forward flow channel V is connected with an inlet of a nitrogen-methane forward flow channel II, and an outlet of the nitrogen-methane forward flow channel II is connected with an inlet pipe of a demethanizer tower bottom evaporator;
The inlet of the synthetic ammonia tail gas channel I is connected with a synthetic ammonia tail gas inlet pipe, the outlet of the synthetic ammonia tail gas channel I is connected with the inlet of the synthetic ammonia tail gas channel III, the outlet of the synthetic ammonia tail gas channel III is connected with the inlet of the synthetic ammonia tail gas channel II, and the outlet of the synthetic ammonia tail gas channel II is connected with the inlet at the lower part of the dehydrogenation tower;
The gas phase outlet at the top of the dehydrogenation tower is connected with the inlet of a hydrogen-rich tail gas channel II, the outlet of the hydrogen-rich tail gas channel II is connected with the inlet of a hydrogen-rich tail gas channel I, and the outlet of the hydrogen-rich tail gas channel I is connected with a hydrogen-rich tail gas outlet pipe; the hydrogen-rich outlet at the upper part of the dehydrogenation tower is connected with the inlet of a hydrogen-rich tail gas channel III of a condenser at the top of the dehydrogenation tower, the outlet of the hydrogen-rich tail gas channel III is connected with the inlet of reflux liquid at the upper part of the dehydrogenation tower, and the liquid phase outlet at the bottom of the dehydrogenation tower is connected with the feed inlet at the middle part of the demethanizer;
the nitrogen-rich outlet of the demethanizer is connected with the inlet of a nitrogen-rich channel I of a top condenser of the demethanizer, the outlet of the nitrogen-rich channel I is connected with a reflux liquid inlet at the upper part of the demethanizer, the methane-rich liquid outlet at the bottom of the demethanizer is connected with the inlet of a methane-rich gas channel I, and the outlet of the methane-rich gas channel I is connected with a methane outlet pipe;
The outlet of the evaporator at the bottom of the demethanizer is connected with an inlet pipe of the evaporator at the bottom of the denitrogenation tower, the outlet of the evaporator at the bottom of the denitrogenation tower is connected with an inlet of a nitrogen methane forward flow channel III, the outlet of the nitrogen methane forward flow channel III is respectively connected with a nitrogen methane return flow channel I and a nitrogen methane forward flow channel IV, and the outlet of the nitrogen methane forward flow channel III is connected with the nitrogen methane forward flow channel IV through a branch pipe A; the outlet of the nitrogen methane backflow channel I is connected with a nitrogen methane feeding pipe of a nitrogen methane circulating air inlet device; the outlets of the nitrogen methane forward flow channel IV are respectively connected with the inlets of a nitrogen methane channel I, a nitrogen methane channel II and a nitrogen methane channel III, the outlets of the nitrogen methane channel I, the nitrogen methane channel II and the nitrogen methane channel III are all connected with the inlet of a nitrogen methane return flow channel II, the outlet of the nitrogen methane return flow channel II is connected with the inlet of a nitrogen methane return flow channel I, and the outlet of the nitrogen methane return flow channel I is connected with a nitrogen methane feeding pipe of a nitrogen methane circulating air inlet device;
The nitrogen-rich outlet at the upper part of the denitrification tower is connected with the inlet of a nitrogen-rich channel II, the outlet of the nitrogen-rich channel II is connected with the inlet of reflux liquid at the upper part of the denitrification tower, the nitrogen-rich outlet at the top of the denitrification tower is connected with the inlet of a nitrogen-rich tail gas channel II, the outlet of the nitrogen-rich tail gas channel II is connected with the inlet of a nitrogen-rich tail gas channel I, and the outlet of the nitrogen-rich tail gas channel I is connected with a nitrogen-rich tail gas outlet pipe;
The liquid argon outlet of the evaporator at the bottom of the denitrification tower is connected with the inlet of the liquid argon channel, and the outlet of the liquid argon channel is connected with the liquid argon outlet pipe.
Further, a methane branch pipe is connected between the methane outlet pipe and the methane feeding pipe.
Furthermore, the precooling compressor is connected with a precooling medium feeding pipe, the precooling compressor is connected with the precooling medium channel through a circulating pipeline, and the precooling medium feeding pipe is connected to the circulating pipeline close to the inlet of the precooling compressor.
Further, the device also comprises a control device; the control device is respectively and electrically connected with the azomethine compressor, the heat exchanger, the precooler, the subcooler, the dehydrogenation tower top condenser, the demethanizer tower bottom evaporator, the demethanizer top condenser, the denitrogenation tower bottom evaporator, the denitrogenation tower and the denitrogenation tower top condenser.
Further, a throttle valve a for throttling and reducing the pressure of the high-pressure nitrogen methane is arranged on a pipeline between the outlet of the nitrogen methane positive flow channel III and the inlet of the nitrogen methane return flow channel I;
The outlet of the nitrogen methane positive flow channel IV is connected with the inlet of the nitrogen methane channel I through a branch pipe B, the outlet of the nitrogen methane positive flow channel IV is connected with the inlet of the nitrogen methane channel II through a branch pipe C, and the outlet of the nitrogen methane positive flow channel IV is connected with the inlet of the nitrogen methane channel III through a branch pipe D; the branch pipes B, C and D are respectively provided with a throttle valve B for throttling and depressurizing the nitrogen methane;
A throttle valve c is arranged on an inlet pipeline of the precooling medium channel;
a throttle valve d is arranged on a pipeline between the outlet of the tail gas channel II of the synthetic ammonia and the inlet of the dehydrogenation tower;
A throttle valve e for throttling and reducing the pressure of the hydrogen-rich tail gas is arranged between the top outlet of the dehydrogenation tower and the inlet of the hydrogen-rich tail gas channel II;
A pipeline between a liquid outlet at the bottom of the dehydrogenation tower and an inlet of the demethanizer is provided with a throttler f used for throttling and reducing the pressure of the liquid at the bottom of the dehydrogenation tower;
a throttle valve g for throttling and reducing the pressure of the methane-rich liquid is arranged on an inlet pipeline of the methane-rich gas channel I;
a throttle valve h for throttling and reducing the pressure of the nitrogen-rich tail gas is arranged on an inlet pipeline of the nitrogen-rich tail gas channel II;
a throttle valve i for throttling and reducing pressure of the precooling medium is arranged on the precooling medium feeding pipe;
the nitrogen feeding pipe and the methane feeding pipe are respectively provided with a throttle valve j for throttling and reducing the pressure of nitrogen and methane;
A throttle valve k for throttling and reducing the pressure of methane is arranged on the methane branch pipe;
a throttle valve l for throttling and reducing the pressure of the liquid argon is arranged on the liquid argon outlet pipe;
The throttle valve a, the throttle valve b, the throttle valve c, the throttle valve d, the throttle valve e, the throttle valve h, the throttle valve i, the throttle valve j, the throttle valve k and the throttle valve l are respectively and electrically connected with the control device.
Furthermore, the connecting pipelines in the device are all cold insulation pipelines.
The invention provides a method for recycling argon and methane from synthesis ammonia tail gas, which is characterized in that the device for recycling argon and methane from synthesis ammonia tail gas by using the precooled nitrogen-methane refrigeration cycle is used for recycling argon and methane from synthesis ammonia tail gas; the method specifically comprises the following steps:
s1, determining a nitrogen-methane ratio according to components of tail gas of synthetic ammonia, and then respectively introducing nitrogen and methane into a nitrogen-methane feed pipe of a nitrogen-methane compressor through a nitrogen feed pipe and a methane feed pipe according to the ratio;
S2, the high-pressure nitrogen methane gas compressed by the nitrogen methane compressor enters a nitrogen methane forward flow channel I of a heat exchanger to be preliminarily cooled to 0 ℃ to minus 30 ℃, the nitrogen methane forward flow channel V entering a precooler from an upper heat exchanger after being preliminarily cooled is precooled to minus 10 ℃ to minus 40 ℃, the precooled high-pressure nitrogen methane gas returns to enter a nitrogen methane forward flow channel II of the heat exchanger to be continuously cooled to minus 80 ℃ to minus 130 ℃, and then the high-pressure nitrogen methane gas exits from the heat exchanger from the middle lower part and enters an evaporator at the bottom of a demethanizer;
The high-pressure nitrogen methane after heat exchange goes out of the bottom evaporator of the demethanizer and enters the bottom evaporator of the denitriding tower, the nitrogen methane which goes out of the bottom evaporator of the denitriding tower returns to the positive flow channel III of the nitrogen methane which enters the heat exchanger after heat exchange is cooled to-140 ℃ to 160 ℃, the high-pressure nitrogen methane which comes out of the positive flow channel III of the nitrogen methane of the heat exchanger is divided into two parts, the first part is throttled and depressurized by a throttle valve a and then enters the nitrogen methane return channel I of the heat exchanger, and the second part enters the positive flow channel IV of the nitrogen methane of the subcooler by a branch pipe A;
The high-pressure nitrogen methane is supercooled to-170 ℃ to-180 ℃ through a nitrogen methane positive flow channel IV of a supercooler, three nitrogen methane flows out of the nitrogen methane positive flow channel IV and is throttled and depressurized through a throttle valve b, and then respectively enters a dehydrogenation tower top condenser, a demethanizer top condenser, a nitrogen methane channel I of the denitrification tower top condenser, a nitrogen methane channel II and a nitrogen methane channel III to provide cold energy for the nitrogen methane, the nitrogen methane heated by the dehydrogenation tower top condenser, the demethanizer top condenser and the denitrification tower top condenser are converged and then enter a supercooler nitrogen methane reflux channel II, the high-pressure nitrogen methane in the supercooler nitrogen methane positive flow channel IV is provided with cold energy, the nitrogen methane from the supercooler nitrogen methane reflux channel II and the nitrogen methane after throttling are converged and enter a heat exchanger nitrogen methane reflux channel I together, and the low-temperature low-pressure nitrogen methane in the nitrogen methane reflux channel I and the synthetic ammonia tail gas of a heat exchanger are provided with cold energy for the nitrogen methane positive flow channel I, the nitrogen methane positive flow channel III and the high-pressure nitrogen methane in the nitrogen methane positive flow channel III are repeatedly compressed and the nitrogen methane is provided with cold energy for the nitrogen methane to flow back through the supercooler;
S3, enabling the pre-cooling medium to enter an inlet pipe of a pre-cooling compressor through a pre-cooling medium feeding pipe, throttling and reducing the pressure of the compressed liquid-phase pre-cooling medium through a throttle valve c, enabling the compressed liquid-phase pre-cooling medium to enter a pre-cooling medium channel of the pre-cooler, controlling the evaporation temperature of the pre-cooling medium to be between 20 ℃ below zero and 43 ℃ below zero, enabling the liquid-phase low-temperature low-pressure pre-cooling medium in the pre-cooling medium channel of the pre-cooler to exchange heat with the synthesis ammonia tail gas in a synthesis ammonia tail gas channel III and the nitrogen methane in a nitrogen methane positive flow channel V in the pre-cooler, providing cold energy, enabling the gas-phase low-temperature low-pressure pre-cooling medium discharged from the pre-cooler to enter the pre-cooling compressor again, and repeatedly carrying out compression circulation refrigeration;
s4, the synthesis ammonia tail gas enters a synthesis ammonia tail gas channel I of a heat exchanger from a synthesis ammonia tail gas inlet pipe and is primarily cooled to 0 ℃ to minus 30 ℃, the synthesis ammonia tail gas enters a synthesis ammonia tail gas channel III of a precooler after exiting the heat exchanger from the synthesis ammonia tail gas channel I and is precooled to minus 10 ℃ to minus 40 ℃, the precooled synthesis ammonia tail gas returns to a synthesis ammonia tail gas channel II of the heat exchanger and is continuously cooled, condensed to minus 140 ℃ to 160 ℃, the synthesis ammonia tail gas exiting the synthesis ammonia tail gas channel II of the heat exchanger is throttled and depressurized by a throttle valve d and enters a dehydrogenation tower, the hydrogen-rich gas exiting the upper part of the dehydrogenation tower enters a hydrogen-rich gas channel I of a dehydrogenation tower condenser after being cooled and condensed and returns to the top of the dehydrogenation tower, liquid is used as hydrogen-rich tail gas exiting the top of the dehydrogenation tower and enters a hydrogen-rich tail gas channel II of the precooler after being throttled and depressurized by a throttle valve e, the hydrogen-rich tail gas exiting the hydrogen-rich tail gas channel II of the supercooler enters a hydrogen-rich tail gas channel I of the heat exchanger, and the hydrogen-rich tail gas exiting the hydrogen-rich tail gas channel I of the heat exchanger after being heated and rewuped enters a hydrogen-rich tail gas outlet pipe;
The liquid at the bottom of the dehydrogenation tower enters a demethanizer after throttling and depressurization by a throttle valve f, the liquid at the bottom of the demethanizer is subjected to rectification separation, the liquid at the bottom of the demethanizer is subjected to heat exchange and evaporation by an evaporator at the bottom of the demethanizer to obtain methane-rich liquid, the methane-rich liquid enters a methane-rich gas channel I from the bottom of a heat exchanger after throttling and depressurization by a throttle valve g, and the heated and rewarmed methane-rich gas is discharged from the top of the heat exchanger and enters a methane outlet pipe;
The nitrogen-rich gas discharged from the upper part of the demethanizer enters a nitrogen-rich channel I of a condenser at the top of the demethanizer, is cooled and condensed and returns to the top of the demethanizer, liquid is used as reflux liquid at the top of the demethanizer to participate in rectification, gas is discharged from the top of the demethanizer and enters a denitriding tower, and is subjected to rectification separation, nitrogen-rich gas at the upper part of the denitriding tower enters a nitrogen-rich channel II of the condenser at the top of the denitriding tower, is cooled and condensed and returns to the top of the denitriding tower, liquid is used as reflux liquid at the top of the denitriding tower and enters a nitrogen-rich tail gas channel II of a subcooler after being throttled and depressurized by a throttle valve h, nitrogen-rich tail gas from the nitrogen-rich tail gas channel II of the subcooler enters a nitrogen-rich tail gas channel I (A5) from the bottom of the heat exchanger, and nitrogen-rich tail gas after being heated and rewarmed enters a nitrogen-rich tail gas outlet pipe from the top of the heat exchanger;
The liquid at the bottom of the denitrification tower is subjected to heat exchange evaporation through an evaporator at the bottom of the denitrification tower to obtain high-purity liquid argon, the liquid argon enters a liquid argon channel of a subcooler, the subcooled liquid argon from the liquid argon channel of the subcooler enters a liquid argon outlet pipe, and the temperature of a liquid argon product is controlled between 170 ℃ below zero and 178 ℃.
Further, the purified synthesis ammonia tail gas comprises: hydrogen, nitrogen, methane and argon, and the molar ratio of argon to methane in the tail gas of the synthetic ammonia is as follows: argon: 4.0 to 12.0 percent of methane: 6.0 to 35 percent.
Further, the pressure of the synthetic ammonia tail gas channel I entering the heat exchanger is controlled to be 4.0-6.0 MPa.
The pressure of the low-pressure nitrogen methane gas flowing back from the nitrogen methane backflow channel I into the nitrogen methane compressor is controlled to be 0.1-0.25 MPa.
The outlet pressure of the nitrogen methane compressor is controlled to be 2.0-5.0 MPa.
The pressure of the dehydrogenation tower is controlled to be 1.5-4.0 MPa.G;
The pressure of the demethanizer is controlled to be 0.5-1.0 MPa.G;
The pressure of the denitrification tower is controlled to be 0.5-1.0 MPa.
Further, the precooling medium adopts ammonia, propane or freon.
Based on the technical scheme, the embodiment of the invention at least has the following technical effects:
(1) According to the device and the method for recycling argon and methane from the synthetic ammonia tail gas, provided by the invention, the refrigeration quantity is provided by recycling the argon and the methane from the synthetic ammonia tail gas through the nitrogen methane refrigeration cycle with precooling, the energy consumption is low, the proportion of the nitrogen methane is simple, the operation is easy, the investment and the operation cost are lower, the process of the precooling unit is mature and easy to control, and the maintenance quantity is less;
(2) The device and the method for recovering argon and methane from the tail gas of the synthetic ammonia provided by the invention have the advantages that the variable efficiency of the compressor is 80%, the single machine energy consumption is the compressor shaft power divided by the standard square yield of the process argon product per hour, the single machine energy consumption of the process argon product is 2.0-3.0 kW/Nm 3, the single machine energy consumption of the nitrogen expansion refrigeration process argon product is 3.5-4.7 kW/Nm 3, the single machine energy consumption is at least reduced by 36.5%, and the cost is far lower than that of the prior art, so that the device and the method have wide market prospect.
(3) According to the device and the method for recycling the argon and the methane from the tail gas of the synthetic ammonia, the precooling unit of the nitrogen-methane refrigeration cycle with precooling is an ammonia precooling unit, a propane precooling unit or a Freon precooling unit, the process of the precooling unit is mature and easy to control, and the maintenance amount is small; the nitrogen methane refrigeration is only provided with one nitrogen methane compressor, the refrigerant is composed of nitrogen and methane, the proportion is adjusted according to the components of the tail gas of the synthetic ammonia, and the operation is simple and quick.
Drawings
FIG. 1 is a schematic diagram of an embodiment of the present invention;
In the figure: 1-synthesis ammonia tail gas inlet pipe, 2-hydrogen-rich tail gas outlet pipe, 3-methane outlet pipe, 4-nitrogen-rich tail gas outlet pipe, 5-nitrogen inlet pipe, 6-methane inlet pipe, 7-liquid argon outlet pipe, 8-nitrogen methane compressor, 9-heat exchanger, 10-precooler, 11-precooler, 12-subcooler, 13-dehydrogenation tower, 14-dehydrogenation tower top condenser, 15-demethanizer tower bottom evaporator, 16-demethanizer, 17-demethanizer top condenser, 18-denitrogenation tower bottom evaporator, 19-denitrogenation tower, 20-denitrogenation tower top condenser, 21-branch pipe A, 22-branch pipe B, 23-branch pipe C, 24-branch pipe D, 25-precooler medium inlet pipe, 26-methane branch pipe; 27. a throttle valve a; 28. a throttle valve b; 29. a throttle valve c; 30. a throttle valve d; 31. a throttle valve e; 32. through a throttle valve f; 33. a throttle valve g; 34. a throttle valve h; 35. a throttle valve i; 36. a throttle valve j; 37. a throttle valve k; 38. a throttle valve l;
A1, synthesizing an ammonia tail gas channel I; a2, synthesizing ammonia tail gas channel II; a3, a hydrogen-rich tail gas channel I; a4, a methane-rich gas channel I; a5, a nitrogen-rich tail gas channel I; a6, a azomethine positive flow channel I; a7, a azomethine positive flow channel II; a8, a nitrogen methane positive flow channel III; a9, a nitrogen methane backflow channel I;
b1, a hydrogen-rich tail gas channel II; b2, a nitrogen methane backflow channel II; b3, a azomethine positive flow channel IV; b4, a liquid argon channel; b5, a nitrogen-rich tail gas channel II;
c1, a hydrogen-rich channel I; c2, azomethine channel I;
d1, a nitrogen-rich channel I; d2, a nitrogen methane channel ii;
e1, a nitrogen-rich channel II; e2, a nitrogen methane channel III;
F1, synthesizing ammonia tail gas channel III; f2, azomethine positive flow channel v; f3, precooling the medium channel.
Detailed Description
Example 1:
an apparatus for recovering argon and methane from synthesis ammonia tail gas by using a precooled nitrogen-methane refrigeration cycle, which is characterized in that: comprises a heat exchanger 9, a subcooler 12, a dehydrogenation tower 13, a demethanizer 16, a denitrification tower 19 and a precooler 11; wherein,
A dehydrogenation tower top condenser 14 is arranged at the upper part of the dehydrogenation tower 13;
The upper part and the lower part of the demethanizer 16 are respectively provided with a demethanizer top condenser 17 and a demethanizer bottom evaporator 15;
the upper part and the lower part of the denitrification tower 19 are respectively provided with a denitrification tower top condenser 20 and a denitrification tower bottom evaporator 18;
The heat exchanger 9 is internally provided with a synthesis ammonia tail gas channel IA 1, a synthesis ammonia tail gas channel IIA 2, a hydrogen-rich tail gas channel IA 3, a methane-rich gas channel IA 4, a nitrogen-rich tail gas channel IA 5, a nitrogen methane forward flow channel IA 6, a nitrogen methane forward flow channel IIA 7, a nitrogen methane forward flow channel IIIA 8 and a nitrogen methane return flow channel IA 9;
The subcooler 12 is internally provided with a hydrogen-rich tail gas channel IIB 1, a nitrogen methane backflow channel IIB 2, a nitrogen methane forward flow channel IVB 3, a liquid argon channel B4 and a nitrogen-rich tail gas channel IIB 5;
a hydrogen-rich channel IC 1 and a nitrogen-methane channel IC 2 are arranged in the dehydrogenation tower top condenser 14;
A nitrogen-rich channel ID 1 and a nitrogen-methane channel II D2 are arranged in the condenser at the top of the demethanizer 16;
A nitrogen-rich channel II E1 and a nitrogen methane channel III E2 are arranged in the denitrogenation tower top condenser;
A synthetic ammonia tail gas channel III F1, a nitrogen methane forward flow channel V F2 and a precooling medium channel F3 are arranged in the precooler 11;
The heat exchanger 9 is connected with a synthetic ammonia tail gas inlet pipe 1, a hydrogen-rich tail gas outlet pipe 2, a methane outlet pipe 3, a nitrogen-rich tail gas outlet pipe 4 and a nitrogen methane circulating air inlet device; the subcooler (12) is connected with a liquid argon outlet pipe 7;
The nitrogen-methane circulation air inlet device comprises a nitrogen-methane compressor 8, wherein a nitrogen inlet pipe is connected to an inlet of the nitrogen-methane compressor 8, a nitrogen inlet pipe 5 and a methane inlet pipe 6 are connected to the nitrogen inlet pipe, a nitrogen outlet pipe is connected to an outlet of the nitrogen-methane compressor 8, an outlet of the nitrogen outlet pipe is connected with an inlet of a nitrogen positive flow channel IA 6, an outlet of the nitrogen positive flow channel IA 6 is connected with an inlet of a nitrogen positive flow channel VF 2, an outlet of the nitrogen positive flow channel VF 2 is connected with an inlet of a nitrogen positive flow channel IIA 7, and an outlet of the nitrogen positive flow channel IIA 7 is connected with an inlet pipe of a demethanizer tower bottom evaporator 15;
The inlet of the synthesis ammonia tail gas channel IA 1 is connected with the synthesis ammonia tail gas inlet pipe 1, the outlet of the synthesis ammonia tail gas channel IA 1 is connected with the inlet of the synthesis ammonia tail gas channel IIIF 1, the outlet of the synthesis ammonia tail gas channel IIIF 1 is connected with the inlet of the synthesis ammonia tail gas channel IIA 2, and the outlet of the synthesis ammonia tail gas channel IIA 2 is connected with the inlet at the lower part of the dehydrogenation tower 13;
The gas phase outlet at the top of the dehydrogenation tower 13 is connected with the inlet of a hydrogen-rich tail gas channel IIB 1, the outlet of the hydrogen-rich tail gas channel IIB 1 is connected with the inlet of a hydrogen-rich tail gas channel IA 3, and the outlet of the hydrogen-rich tail gas channel IA 3 is connected with a hydrogen-rich tail gas outlet pipe 2; the hydrogen-rich outlet at the upper part of the dehydrogenation tower 13 is connected with the inlet of a hydrogen-rich tail gas channel IIIC 1 of a dehydrogenation tower top condenser 14, the outlet of the hydrogen-rich tail gas channel IIIC 1 is connected with the reflux inlet at the upper part of the dehydrogenation tower 13, and the liquid phase outlet at the bottom of the dehydrogenation tower 13 is connected with the feed inlet at the middle part of the demethanizer 16;
The nitrogen-rich outlet of the demethanizer 16 is connected with the inlet of a nitrogen-rich channel ID 1 of a demethanizer top condenser 17, the outlet of the nitrogen-rich channel ID 1 is connected with the reflux inlet at the upper part of the demethanizer 16, the methane-rich liquid outlet at the bottom of the demethanizer 16 is connected with the inlet of a methane-rich channel IA 4, and the outlet of the methane-rich channel IA 4 is connected with a methane outlet pipe 3;
The outlet of the demethanizer bottom evaporator 15 is connected with an inlet pipe of the denitrogenation tower bottom evaporator 18, the outlet of the denitrogenation tower bottom evaporator 18 is connected with an inlet of a nitrogen methane forward flow channel IIIA 8, the outlet of the nitrogen methane forward flow channel IIIA 8 is respectively connected with a nitrogen methane return flow channel IA 9 and a nitrogen methane forward flow channel IVB 3, and the outlet of the nitrogen methane forward flow channel IIIA 8 is connected with the nitrogen methane forward flow channel IVB 3 through a branch pipe A21; the outlet of the nitrogen methane backflow channel IA 9 is connected with a nitrogen methane feeding pipe of a nitrogen methane circulating air inlet device; the outlets of the azote positive flow channel IVB 3 are respectively connected with inlets of a azote channel IC 2, a azote channel IID 2 and a azote channel IIIE 2, the outlets of the azote channel IC 2, the azote channel IID 2 and the azote channel IIIE 2 are connected with inlets of a azote return flow channel IIB 2, the outlet of the azote return flow channel IIB 2 is connected with an inlet of a azote return flow channel IA 9, and the outlet of the azote return flow channel IA 9 is connected with a azote feed pipe of the azote circulating air inlet device;
The nitrogen-rich outlet at the upper part of the denitrification tower 19 is connected with the inlet of a nitrogen-rich channel IIE 1, the outlet of the nitrogen-rich channel IIE 1 is connected with the inlet of reflux liquid at the upper part of the denitrification tower, the nitrogen-rich outlet at the top of the denitrification tower 19 is connected with the inlet of a nitrogen-rich tail gas channel IIB 5, the outlet of the nitrogen-rich tail gas channel IIB 5 is connected with the inlet of a nitrogen-rich tail gas channel IA 5, and the outlet of the nitrogen-rich tail gas channel IA 5 is connected with a nitrogen-rich tail gas outlet pipe 4;
the liquid argon outlet of the bottom evaporator 18 of the denitrification tower is connected with the inlet of the liquid argon channel B4, and the outlet of the liquid argon channel B4 is connected with the liquid argon outlet pipe 7.
The device and the method for recycling the argon and the methane from the synthetic ammonia tail gas by the precooled nitrogen-methane refrigeration cycle provided by the invention have the advantages that the precooled nitrogen-methane refrigeration cycle is used for recycling the argon and the methane from the synthetic ammonia tail gas to provide cold energy, the energy consumption is low, the proportion of the nitrogen-methane is simple, the operation is easy, the investment and the operation cost are lower, the process of a precooling unit is mature and easy to control, and the maintenance amount is less; the device and the method for recycling argon and methane from the synthetic ammonia tail gas by the nitrogen methane refrigeration cycle with precooling, provided by the invention, have the advantages that the variable efficiency of a compressor is 80%, the single machine energy consumption is the compressor shaft power divided by the standard product yield of the process argon product per hour, the single machine energy consumption of the process argon product is 2.0-3.0 kW/Nm 3, the single machine energy consumption of the nitrogen expansion refrigeration process argon product is 3.5-4.7 kW/Nm 3, the single machine energy consumption is reduced by 40%, the cost is far lower than that of the prior art, and the device has wide market prospect; according to the device and the method for recycling argon and methane from the synthetic ammonia tail gas by the nitrogen-methane refrigeration cycle with precooling, which are provided by the invention, the precooling machine set of the nitrogen-methane refrigeration cycle with precooling is an ammonia precooling machine set, a propane precooling machine set or a Freon precooling machine set, the process of the precooling machine set is mature and easy to control, and the maintenance amount is small; the nitrogen methane refrigeration is only provided with one nitrogen methane compressor, the refrigerant is composed of nitrogen and methane, the proportion is adjusted according to the components of the tail gas of the synthetic ammonia, and the operation is simple and quick.
As an alternative embodiment, a methane branch pipe 26 is connected between the methane outlet pipe 3 and the methane feed pipe 6.
As an alternative embodiment, the pre-cooling compressor 10 is connected with a pre-cooling medium feeding pipe 25, the pre-cooling compressor 10 is connected with the pre-cooling medium channel F3 through a circulation pipeline, and the pre-cooling medium feeding pipe (25) is connected to the circulation pipeline near the inlet of the pre-cooling compressor (10).
As an alternative embodiment, the device further comprises a control device; the control device is respectively and electrically connected with a azomethane compressor 8, a heat exchanger 9, a precooler compressor 10, a precooler 11, a subcooler 12, a dehydrogenation tower 13, a dehydrogenation tower top condenser 14, a demethanizer tower bottom evaporator 15, a demethanizer 16, a demethanizer top condenser 17, a denitrogenation tower bottom evaporator 18, a denitrogenation tower 19 and a denitrogenation tower top condenser 20.
As an alternative embodiment, a throttle valve a27 for throttling and reducing the pressure of the high-pressure nitrogen methane is arranged on a pipeline between the outlet of the nitrogen methane positive flow channel IIIA 8 and the inlet of the nitrogen methane return flow channel IA 9;
The outlet of the nitrogen methane positive flow channel IVB 3 is connected with the inlet of the nitrogen methane channel IC 2 through a branch pipe B22, the outlet of the nitrogen methane positive flow channel IVB 3 is connected with the inlet of the nitrogen methane channel IID 2 through a branch pipe C23, and the outlet of the nitrogen methane positive flow channel IVB 3 is connected with the inlet of the nitrogen methane channel IIIE 2 through a branch pipe D24; the branch pipes B22, C23 and D24 are respectively provided with a throttle valve B28 for throttling and reducing the pressure of the nitrogen and methane, and the opening of the throttle valve B28 is adjusted to adjust the circulation quantity of the nitrogen and methane, so that the pressure and the temperature of each point of the nitrogen and methane system are in the correct range;
a throttle valve c29 is arranged on an inlet pipeline of the precooling medium channel F3;
a throttle valve d30 is arranged on a pipeline between the outlet of the synthesis ammonia tail gas channel IIA 2 and the inlet of the co-dehydrogenation tower 13;
A throttle valve e31 for throttling and reducing the pressure of the hydrogen-rich tail gas is arranged between the top outlet of the dehydrogenation tower 13 and the inlet of the hydrogen-rich tail gas channel IIB 1;
A pipeline between a liquid outlet at the bottom of the dehydrogenation tower 13 and an inlet of the demethanizer 16 is provided with a throttled valve f32 for throttling and reducing the pressure of the liquid at the bottom of the dehydrogenation tower 13;
a throttle valve g33 for throttling and reducing the pressure of the methane-rich liquid is arranged on an inlet pipeline of the methane-rich gas channel IA 4;
a throttle valve h34 for throttling and reducing the pressure of the nitrogen-rich tail gas is arranged on an inlet pipeline of the nitrogen-rich tail gas channel IIB 5;
a throttle valve i35 for throttling and reducing pressure of the precooling medium is arranged on the precooling medium feed pipe 25;
The nitrogen feeding pipe 5 and the methane feeding pipe 6 are respectively provided with a throttle valve j36 for throttling and reducing the pressure of nitrogen and methane;
a throttle valve k37 for throttling and reducing the pressure of methane is arranged on the methane branch pipe 26;
A throttle valve l38 for throttling and reducing the pressure of the liquid argon is arranged on the liquid argon outlet pipe 7;
the throttle valve a27; a throttle valve b28; a throttle valve c29; a throttle valve d30; a throttle valve e31; through a throttle f32; a throttle valve g33; a throttle valve h34; a throttle valve i35; throttle valve j36; a throttle valve k37; the throttle valves l38 are electrically connected to the control device, respectively.
As an alternative embodiment, the connecting pipes in the device are all cold insulation pipelines.
Example 2:
A method for recovering argon and methane from synthesis ammonia tail gas, which uses the precooled nitrogen methane refrigeration cycle in the embodiment 1 to recover argon and methane from synthesis ammonia tail gas, and uses the device for recovering argon and methane from synthesis ammonia tail gas; the method specifically comprises the following steps:
S1, the purified synthetic ammonia tail gas according to the synthetic ammonia tail gas components comprises the following components: the molar ratio of the hydrogen, the nitrogen, the methane and the argon to the azomethane is as follows: methane: 30%, nitrogen: 70, then respectively introducing nitrogen and methane into the nitrogen-methane feed pipe of the nitrogen-methane compressor 8 through the nitrogen feed pipe 5 and the methane feed pipe 6 according to the proportion,
When the purified synthetic ammonia tail gas component changes, the nitrogen-methane ratio is deviated from the design value, the nitrogen-methane ratio is required to be redetermined according to the changed synthetic ammonia tail gas component, and nitrogen and methane which need to be supplemented are introduced into an inlet pipe of a nitrogen-methane compressor 8 through a nitrogen inlet pipe 5, a methane inlet pipe 6 or a methane branch pipe 26;
S2, the high-pressure nitrogen methane gas compressed by the nitrogen methane compressor 8 enters a nitrogen methane forward flow channel IA 6 of the heat exchanger 9 to be primarily cooled to-10 ℃, the outlet pressure of the nitrogen methane compressor 8 is controlled to be 4.0MPa.G, the nitrogen methane forward flow channel VF 2 of the nitrogen methane compressor 8 enters a precooler 11 from the upper part after being primarily cooled, the precooled high-pressure nitrogen methane gas returns to enter a nitrogen methane forward flow channel IIA 7 of the heat exchanger 9 to be continuously cooled to-86 ℃, and then the nitrogen methane forward flow channel IIA enters a demethanizer tower bottom evaporator 15 from the middle lower part after being discharged from the heat exchanger 9;
The high-pressure nitrogen methane after heat exchange enters a bottom evaporator 15 of a demethanizer and enters a bottom evaporator 18 of the denitriding tower, is cooled to-131 ℃, and then enters a nitrogen methane forward flow channel IIIA 8 of the heat exchanger 9 after being returned by the bottom evaporator 18 of the denitriding tower, is cooled to-160 ℃, the high-pressure nitrogen methane coming out of the nitrogen methane forward flow channel IIIA 8 of the heat exchanger 9 is divided into two parts, the first part enters a nitrogen methane return flow channel IA 9 of the heat exchanger 9 after being throttled and depressurized by a throttle valve a27, and the second part enters a nitrogen methane forward flow channel IVB 3 of the subcooler 12;
The high-pressure nitrogen methane is supercooled to minus 173 ℃ through a nitrogen methane forward flow passage IVB 3 of a supercooler 12, three nitrogen methane flows out of the nitrogen methane forward flow passage IVB 3 and is throttled and depressurized through a throttle valve B28, and then respectively enters a dehydrogenation tower top condenser 14, a demethanizer top condenser 17 and a nitrogen methane passage I C2 of a denitrification tower top condenser 20, a nitrogen methane passage II D2 and a nitrogen methane passage III E2 for providing cold energy for the nitrogen methane, the nitrogen methane which comes from the dehydrogenation tower top condenser 14, the demethanizer top condenser 17 and the denitrification tower top condenser 20 and is heated is converged and then enters a supercooler 12 nitrogen methane reflux passage II B2, the high-pressure nitrogen methane in the nitrogen methane forward flow passage IVB 3 of the supercooler 12 is supplied with cold energy, the nitrogen methane which comes from the supercooler 12 nitrogen methane reflux passage II B2 and the nitrogen methane which comes from the first flow are converged and enter a heat exchanger 9 nitrogen methane reflux passage IA 9, low-temperature low-pressure nitrogen methane in the nitrogen methane reflux passage IA 9 and the synthesis ammonia methane in the heat exchanger 9 are combined, the nitrogen methane reflux passage IA 2 is compressed and the nitrogen methane in the nitrogen methane forward flow passage I9, the nitrogen methane reflux passage I is compressed and the nitrogen methane in the normal temperature is controlled by the supercooler 12, the nitrogen methane forward flow passage I9 is compressed and the nitrogen methane reflux flow is compressed by the nitrogen methane forward flow passage I8, and the nitrogen methane is compressed by the high-pressure of the nitrogen methane flow is compressed by the nitrogen methane in the nitrogen methane forward flow passage I9;
S3, the precooling medium adopts ammonia, the precooling medium enters an inlet pipe of the precooling compressor 10 through a precooling medium feeding pipe 25, the compressed liquid-phase precooling medium enters a precooling medium channel F3 of the precooler 11 after being throttled and depressurized by a throttle valve c29, the evaporation temperature of the precooling medium is controlled at minus 20 ℃, the liquid-phase low-temperature low-pressure precooling medium in the precooling medium channel F3 of the precooler 11 exchanges heat with the synthetic ammonia tail gas in a synthetic ammonia tail gas channel III F1 and the nitrogen methane in a nitrogen methane forward flow channel V2 in order to provide cold energy, and the gas-phase low-temperature low-pressure precooling medium discharged from the precooler 11 enters the precooling compressor 10 again to repeatedly perform compression cycle refrigeration;
S4, the pressure of purified synthetic ammonia tail gas is 6.0MPa.G, the synthetic ammonia tail gas enters a synthetic ammonia tail gas channel IA 1 of a heat exchanger 9 from a synthetic ammonia tail gas inlet pipe 1, is primarily cooled to-10 ℃, enters a synthetic ammonia tail gas channel IIIF 1 of a precooler 11 after exiting the heat exchanger 9 from the synthetic ammonia tail gas channel IA 1, is precooled to-15 ℃, returns to a synthetic ammonia tail gas channel IIA 2 of the heat exchanger 9 after precooling, is continuously cooled, is condensed to-155 ℃, enters a dehydrogenation tower 13 after throttling and depressurization by a throttle valve d30, the pressure of the dehydrogenation tower 13 is controlled to be 4.0MPa.G, is separated by rectification, hydrogen-rich gas from the upper part of the dehydrogenation tower 13 enters a hydrogen-rich channel IC 1 of a dehydrogenation tower top condenser 14, is cooled and condensed, returns to the top of the dehydrogenation tower 13, liquid is taken as reflux liquid at the top of the dehydrogenation tower 13, is discharged from the top of the dehydrogenation tower and enters a hydrogen-rich supercooler 12B 1 after throttling and depressurization by a throttle valve e31 to 2.55MPa.G, enters a hydrogen-rich channel 12B 1 of a subcooler 12, and enters a hydrogen-rich tail gas channel I from the hydrogen-rich channel 9 from the heat exchanger 9, and enters a hydrogen-rich channel I from the hydrogen-rich channel I, and enters a hydrogen-rich channel I of the hydrogen-rich channel 9 from the hydrogen-rich channel I, and enters a hydrogen-rich channel I and is heated from the hydrogen-rich channel 9;
The liquid at the bottom of the dehydrogenation tower 13 enters a demethanizer 16 after being throttled and depressurized by a throttle valve f32, the pressure of the demethanizer 16 is controlled to be 0.8MPa.G, the liquid at the bottom of the demethanizer 16 is subjected to rectification separation, the liquid at the bottom of the demethanizer is subjected to heat exchange and evaporation by a demethanizer bottom evaporator 15 to obtain methane-rich liquid, the methane-rich liquid enters a methane-rich gas channel IA 4 from the bottom of a heat exchanger 9 after being throttled and depressurized by a throttle valve g33, and the heated and rewarmed methane-rich gas is discharged from the top of the heat exchanger 9 and enters a methane outlet pipe 3;
The nitrogen-rich gas discharged from the upper part of the demethanizer 16 enters a nitrogen-rich channel ID 1 of a demethanizer top condenser 17, is cooled and condensed, returns to the top of the demethanizer 16, takes part in rectification by taking liquid as a reflux liquid at the top of the demethanizer 16, gas is discharged from the top of the demethanizer 16 and enters a denitrogenation tower 19, the pressure of the denitrogenation tower 19 is controlled at 0.7MPa.G, the nitrogen-rich gas at the upper part of the denitrogenation tower 19 enters a nitrogen-rich channel IIE 1 of a denitrogenation tower condenser 20 through rectification separation, is cooled and condensed, returns to the top of the denitrogenation tower 19, takes part in rectification by taking liquid as a reflux liquid at the top of the denitrogenation tower 19, takes part in rectification by taking gas out from the top of the denitrogenation tower 19 and is throttled to be reduced to 0.3MPa.G by a throttle valve h34, and then enters a nitrogen-rich tail gas channel IIB 5 of the subcooler 12, nitrogen-rich tail gas from the bottom of the subcooler 12 enters a nitrogen-rich tail gas channel IIA 5 from the bottom of the heat exchanger 9, and the heated and rewarmed nitrogen-rich tail gas enters a nitrogen-rich tail gas outlet pipe 4 from the top of the heat exchanger 9;
The liquid at the bottom of the denitrification tower 19 is subjected to heat exchange evaporation through a denitrification tower bottom evaporator 18 to obtain high-purity liquid argon, the liquid argon enters a liquid argon channel B4 of the subcooler 12, the subcooled liquid argon from the liquid argon channel B4 of the subcooler 12 enters a liquid argon outlet pipe 7, and the temperature of a liquid argon product is controlled at-175 ℃.
In this example, the mole percentages of the components in the synthesis ammonia tail gas and the mole percentages of the components in the obtained hydrogen-rich tail gas, methane, nitrogen-rich tail gas and liquid argon are shown in table 1 below:
TABLE 1 mole percent of the components
| Argon gas | Methane | Nitrogen gas | Hydrogen gas | |
| Tail gas of synthetic ammonia | 8.1495％ | 13.2180％ | 56.1022％ | 22.5303％ |
| Hydrogen-rich tail gas | 1.5000％ | 0.0019％ | 32.1342％ | 66.3640％ |
| Methane | 1.0000％ | 98.9431％ | 0.0569％ | - |
| Nitrogen-rich tail gas | 1.4997％ | - | 87.7719％ | 10.7284％ |
| Liquid argon component | 99.9994％ | 0.0001％ | 0.0005％ | - |
The variable efficiency of the compressor is 80%, the single machine energy consumption is the compressor shaft power divided by the standard square output of the argon product of the process per hour, the argon product single machine energy consumption is 2.524kW/Nm 3, the nitrogen expansion refrigeration process argon product single machine energy consumption is 4.642kW/Nm 3, and the single machine energy consumption is reduced by 45.4%.
Example 3:
A method for recovering argon and methane from synthesis ammonia tail gas, which uses the precooled nitrogen methane refrigeration cycle in the embodiment 1 to recover argon and methane from synthesis ammonia tail gas, and uses the device for recovering argon and methane from synthesis ammonia tail gas; the method specifically comprises the following steps:
S1, the purified synthetic ammonia tail gas according to the synthetic ammonia tail gas components comprises the following components: the molar ratio of the hydrogen, the nitrogen, the methane and the argon to the azomethane is as follows: methane: 33%, nitrogen: 67, then according to the proportion, respectively introducing nitrogen and methane into the nitrogen-methane feed pipe of the nitrogen-methane compressor 8 through the nitrogen feed pipe 5 and the methane feed pipe 6,
When the purified synthetic ammonia tail gas component changes, the nitrogen-methane ratio is deviated from the design value, the nitrogen-methane ratio is required to be redetermined according to the changed synthetic ammonia tail gas component, and nitrogen and methane which need to be supplemented are introduced into an inlet pipe of a nitrogen-methane compressor 8 through a nitrogen inlet pipe 5, a methane inlet pipe 6 or a methane branch pipe 26;
s2, the high-pressure nitrogen methane gas compressed by the nitrogen methane compressor 8 enters a nitrogen methane forward flow channel IA 6 of the heat exchanger 9 to be primarily cooled to-29 ℃, the outlet pressure of the nitrogen methane compressor 8 is controlled to be 3.42MPa.G, the nitrogen methane forward flow channel VF 2 of the nitrogen methane compressor 8 enters a precooler 11 from the upper part after being primarily cooled, the precooled high-pressure nitrogen methane gas returns to enter a nitrogen methane forward flow channel IIA 7 of the heat exchanger 9 to be continuously cooled to-103 ℃, and then the nitrogen methane forward flow channel IIA enters a demethanizer tower bottom evaporator 15 from the middle lower part after being discharged from the heat exchanger 9;
The high-pressure nitrogen methane after heat exchange enters a bottom evaporator 15 of a demethanizer and enters a bottom evaporator 18 of the denitriding tower, is cooled to-131 ℃, and then enters a nitrogen methane forward flow channel IIIA 8 of the heat exchanger 9 after being returned by the bottom evaporator 18 of the denitriding tower, is cooled to-160 ℃, the high-pressure nitrogen methane coming out of the nitrogen methane forward flow channel IIIA 8 of the heat exchanger 9 is divided into two parts, the first part enters a nitrogen methane return flow channel IA 9 of the heat exchanger 9 after being throttled and depressurized by a throttle valve a27, and the second part enters a nitrogen methane forward flow channel IVB 3 of the subcooler 12;
the high-pressure nitrogen methane is supercooled to minus 175 ℃ through a nitrogen methane forward flow passage IVB 3 of a supercooler 12, three nitrogen methane flows out of the nitrogen methane forward flow passage IVB 3 and is throttled and depressurized through a throttle valve B28, and then respectively enters a dehydrogenation tower top condenser 14, a demethanizer top condenser 17 and a nitrogen methane passage I C2 of a denitrification tower top condenser 20, a nitrogen methane passage II D2 and a nitrogen methane passage III E2 for providing cold energy for the nitrogen methane, the nitrogen methane which comes from the dehydrogenation tower top condenser 14, the demethanizer top condenser 17 and the denitrification tower top condenser 20 and is heated is converged and then enters a supercooler 12 nitrogen methane reflux passage II B2, the high-pressure nitrogen methane in the nitrogen methane forward flow passage IVB 3 of the supercooler 12 is supplied with cold energy, the nitrogen methane which comes from the supercooler 12 nitrogen methane reflux passage II B2 and the nitrogen methane which comes from the first flow are converged and enter a heat exchanger 9 nitrogen methane reflux passage IA 9, low-temperature low-pressure nitrogen methane in the nitrogen methane reflux passage IA 9 and the synthesis ammonia methane in the heat exchanger 9 are combined, the nitrogen methane reflux passage IA 2 is compressed and the nitrogen methane in the nitrogen methane forward flow passage I9, the nitrogen methane reflux is compressed and the nitrogen methane forward flow passage I8.16 is controlled by the heat exchanger 9, and the nitrogen methane is compressed and the nitrogen methane in the normal pressure flow passage I9 is compressed and the normal pressure is compressed and the nitrogen methane flow through the nitrogen methane forward flow passage I9;
S3, the precooling medium adopts propane, the precooling medium enters an inlet pipe of the precooling compressor 10 through a precooling medium feeding pipe 25, the compressed liquid-phase precooling medium enters a precooling medium channel F3 of the precooler 11 after being throttled and depressurized by a throttle valve c29, the evaporation temperature of the precooling medium is controlled at-42 ℃, the liquid-phase low-temperature low-pressure precooling medium in the precooling medium channel F3 of the precooler 11 exchanges heat with the synthetic ammonia tail gas in a synthetic ammonia tail gas channel III F1 and the nitrogen methane in a nitrogen methane forward flow channel V2 in order to provide cold energy, and the gas-phase low-temperature low-pressure precooling medium discharged from the precooler 11 enters the precooling compressor 10 again to repeatedly perform compression cycle refrigeration;
S4, the purified synthetic ammonia tail gas pressure is 5.0MPa.G, the synthetic ammonia tail gas enters a synthetic ammonia tail gas channel IA 1 of a heat exchanger 9 from a synthetic ammonia tail gas inlet pipe 1, is primarily cooled to-29 ℃, enters a synthetic ammonia tail gas channel IIIF 1 of a precooler 11 after exiting the heat exchanger 9 from the synthetic ammonia tail gas channel IA 1, is precooled to-38 ℃, returns to a synthetic ammonia tail gas channel IIA 2 of the heat exchanger 9 after precooling, is continuously cooled, is condensed to-160 ℃, enters a dehydrogenation tower 13 after throttling and depressurization by a throttle valve d30, the pressure of the dehydrogenation tower 13 is controlled to be 3.4MPa.G, is separated by rectification, hydrogen-rich gas from the upper part of the dehydrogenation tower 13 enters a hydrogen-rich channel IC 1 of a dehydrogenation tower top condenser 14, is cooled and condensed, and returns to the top of the dehydrogenation tower 13, the liquid is used as a reflux liquid of the dehydrogenation tower top 13, the gas enters a hydrogen-rich channel IIB 1 of a subcooler 12 after throttling and depressurization by a throttle valve e31 to 2.55MPa.G, enters a hydrogen-rich channel IIB 1 of a subcooler 12, and enters a hydrogen-rich tail gas channel I from the hydrogen-rich tail gas channel 9 from the heat exchanger 9, and enters a hydrogen-rich tail gas channel I from the hydrogen-rich channel I of the hydrogen-rich tail gas channel 9 after being heated by a heat exchanger 3;
The liquid at the bottom of the dehydrogenation tower 13 enters a demethanizer 16 after being throttled and depressurized by a throttle valve f32, the pressure of the demethanizer 16 is controlled to be 0.7MPa.G, the liquid at the bottom of the demethanizer 16 is subjected to rectification separation, the liquid at the bottom of the demethanizer is subjected to heat exchange and evaporation by a demethanizer bottom evaporator 15 to obtain methane-rich liquid, the methane-rich liquid enters a methane-rich gas channel IA 4 from the bottom of a heat exchanger 9 after being throttled and depressurized by a throttle valve g33, and the heated and rewarmed methane-rich gas is discharged from the top of the heat exchanger 9 and enters a methane outlet pipe 3;
the nitrogen-rich gas discharged from the upper part of the demethanizer 16 enters a nitrogen-rich channel ID 1 of a demethanizer top condenser 17, is cooled and condensed, returns to the top of the demethanizer 16, takes part in rectification by taking liquid as a reflux liquid at the top of the demethanizer 16, gas is discharged from the top of the demethanizer 16 and enters a denitrogenation tower 19, the pressure of the denitrogenation tower 19 is controlled at 0.66MPa.G, the nitrogen-rich gas at the upper part of the denitrogenation tower 19 enters a nitrogen-rich channel IIE 1 of a denitrogenation tower condenser 20 through rectification separation, is cooled and condensed, returns to the top of the denitrogenation tower 19, takes part in rectification by taking liquid as a reflux liquid at the top of the denitrogenation tower 19, takes part in rectification by taking gas out from the top of the denitrogenation tower 19 and is throttled to be reduced to 0.3MPa.G by a nitrogen-rich tail gas channel IIB 5 of the subcooler 12, the nitrogen-rich tail gas from the nitrogen-rich tail gas channel IIB 5 of the subcooler 12 enters a nitrogen-rich tail gas channel IA 5 from the bottom of the heat exchanger 9, and the nitrogen-rich tail gas after being heated and reheated enters a nitrogen-rich tail gas outlet pipe 4 from the top of the heat exchanger 9;
The liquid at the bottom of the denitrification tower 19 is subjected to heat exchange evaporation through a denitrification tower bottom evaporator 18 to obtain high-purity liquid argon, the liquid argon enters a liquid argon channel B4 of the subcooler 12, the subcooled liquid argon from the liquid argon channel B4 of the subcooler 12 enters a liquid argon outlet pipe 7, and the temperature of a liquid argon product is controlled at-175 ℃.
In this example, the mole percentages of the components in the synthesis ammonia tail gas and the mole percentages of the components in the obtained hydrogen-rich tail gas, methane, nitrogen-rich tail gas and liquid argon are shown in table 2 below:
TABLE 2 mole percent of the components
| Argon gas | Methane | Nitrogen gas | Hydrogen gas | |
| Tail gas of synthetic ammonia | 12.0％ | 8.0％ | 50.0％ | 30.0％ |
| Hydrogen-rich tail gas | 1.5000％ | 0.0002％ | 25.4854％ | 73.0144％ |
| Methane | 1.0000％ | 98.9700％ | 0.0300％ | - |
| Nitrogen-rich tail gas | 1.5021％ | - | 88.2579％ | 10.2400％ |
| Liquid argon component | 99.9994％ | 0.0001％ | 0.0005％ | - |
The variable efficiency of the compressor is 80%, the single machine energy consumption is the shaft power of the compressor divided by the standard square output of the argon product of the process per hour, the argon product single machine energy consumption is 2.242kW/Nm 3, the nitrogen expansion refrigeration process argon product single machine energy consumption is 3.528kW/Nm 3, and the single machine energy consumption is reduced by 36.5 percent
Example 4:
A method for recovering argon and methane from synthesis ammonia tail gas, which uses the precooled nitrogen methane refrigeration cycle in the embodiment 1 to recover argon and methane from synthesis ammonia tail gas, and uses the device for recovering argon and methane from synthesis ammonia tail gas; the method specifically comprises the following steps:
S1, the purified synthetic ammonia tail gas according to the synthetic ammonia tail gas components comprises the following components: the molar ratio of the hydrogen, the nitrogen, the methane and the argon to the azomethane is as follows: methane: 35%, nitrogen: 65, then according to the proportion, respectively introducing nitrogen and methane into the nitrogen-methane feed pipe of the nitrogen-methane compressor 8 through the nitrogen feed pipe 5 and the methane feed pipe 6,
When the purified synthetic ammonia tail gas component changes, the nitrogen-methane ratio is deviated from the design value, the nitrogen-methane ratio is required to be redetermined according to the changed synthetic ammonia tail gas component, and nitrogen and methane which need to be supplemented are introduced into an inlet pipe of a nitrogen-methane compressor 8 through a nitrogen inlet pipe 5, a methane inlet pipe 6 or a methane branch pipe 26;
S2, the high-pressure nitrogen methane gas compressed by the nitrogen methane compressor 8 enters a nitrogen methane forward flow channel IA 6 of the heat exchanger 9 to be primarily cooled to-30 ℃, the outlet pressure of the nitrogen methane compressor 8 is controlled to be 2.62MPa.G, the nitrogen methane forward flow channel VF 2 of the nitrogen methane compressor 8 enters a precooler 11 from the upper part after being primarily cooled, the precooled high-pressure nitrogen methane gas returns to enter a nitrogen methane forward flow channel IIA 7 of the heat exchanger 9 to be continuously cooled to-121 ℃, and then the nitrogen methane forward flow channel IIA enters a demethanizer tower bottom evaporator 15 from the middle lower part after being discharged from the heat exchanger 9;
The high-pressure nitrogen methane after heat exchange enters a bottom evaporator 15 of a demethanizer and enters a bottom evaporator 18 of the denitriding tower, is cooled to 136 ℃ below zero, returns to a nitrogen methane forward flow channel IIIA 8 entering a heat exchanger 9 to be cooled to 150 ℃ below zero, and is separated into two high-pressure nitrogen methane from the nitrogen methane forward flow channel IIIA 8 of the heat exchanger 9, the first nitrogen methane enters a nitrogen methane return flow channel IA 9 of the heat exchanger 9 after being throttled and depressurized by a throttle valve a27, and the second nitrogen methane enters a nitrogen methane forward flow channel IVB 3 of a subcooler 12;
The high-pressure nitrogen methane is supercooled to minus 178 ℃ through a nitrogen methane forward flow passage IVB 3 of a supercooler 12, three nitrogen methane flows out of the nitrogen methane forward flow passage IVB 3 and is throttled and depressurized through a throttle valve B28, and then respectively enters a dehydrogenation tower top condenser 14, a demethanizer top condenser 17 and a nitrogen methane passage IC 2 of a denitrification tower top condenser 20, cold energy is provided for the nitrogen methane passage IC 2, the nitrogen methane which is heated from the dehydrogenation tower top condenser 14, the demethanizer top condenser 17 and the denitrification tower top condenser 20 is converged and then enters a supercooler 12 nitrogen methane reflux passage IIB 2, cold energy is provided for the high-pressure nitrogen methane in the nitrogen methane forward flow passage IVB 3 of the supercooler 12, the nitrogen methane from the supercooler 12 nitrogen methane reflux passage IIB 2 and the nitrogen methane which is throttled by the first flow are converged and enter a heat exchanger 9 nitrogen methane reflux passage IA 9, low-temperature low-pressure nitrogen methane in the nitrogen methane reflux passage IA 9 and a synthetic ammonia channel IIA 1 of the heat exchanger 9, the synthetic ammonia methane is compressed and the nitrogen methane in the nitrogen methane reflux passage IIA 9, the nitrogen methane reflux passage I is compressed and the nitrogen methane forward flow passage IIA is controlled to be compressed in the normal temperature and the nitrogen methane forward flow passage IIA 9, the high-pressure is compressed and the nitrogen methane reflux passage I is compressed and the nitrogen methane in the normal pressure flow passage IIA 9 is compressed and the normal pressure and the pressure is compressed and the nitrogen methane flow in the nitrogen methane flow passage is 8;
S3, adopting Freon as a precooling medium, enabling the precooling medium to enter an inlet pipe of the precooling compressor 10 through a precooling medium feeding pipe 25, enabling a compressed liquid-phase precooling medium to enter a precooling medium channel F3 of the precooler 11 after being throttled and depressurized by a throttle valve c29, controlling the evaporation temperature of the precooling medium to be 42 ℃ below zero, enabling the liquid-phase low-temperature low-pressure precooling medium in the precooling medium channel F3 of the precooler 11 to exchange heat with the synthetic ammonia tail gas in a synthetic ammonia tail gas channel III F1 and the nitrogen methane in a nitrogen methane forward flow channel V F2 in the precooler 11, providing cold energy, and enabling the gas-phase low-temperature low-pressure precooling medium discharged from the precooler 11 to enter the precooling compressor 10 again to repeatedly perform compression cycle refrigeration;
S4, the pressure of purified synthetic ammonia tail gas is 4.0MPa.G, the synthetic ammonia tail gas enters a synthetic ammonia tail gas channel IA 1 of a heat exchanger 9 from a synthetic ammonia tail gas inlet pipe 1, is primarily cooled to minus 30 ℃, enters a synthetic ammonia tail gas channel IIIF 1 of a precooler 11 after exiting the heat exchanger 9 from the synthetic ammonia tail gas channel IA 1, is precooled to minus 38 ℃, returns to a synthetic ammonia tail gas channel IIA 2 of the heat exchanger 9 after precooling, is continuously cooled, is condensed to minus 150 ℃, enters a dehydrogenation tower 13 after throttling and depressurization by a throttle valve d30, the pressure of the dehydrogenation tower 13 is controlled to be 2.0MPa.G, is separated by rectification, hydrogen-rich gas from the upper part of the dehydrogenation tower 13 enters a hydrogen-rich gas channel IC 1 of a dehydrogenation tower top condenser 14, is cooled and condensed, then returns to the top of the dehydrogenation tower 13, liquid is used as a reflux liquid of the dehydrogenation tower top 13, gas enters a hydrogen-rich channel IIB 1 of a subcooler 12 after throttling and depressurization by a throttle valve e31 to 1.9MPa.G, enters a hydrogen-rich channel IIB 1 of a subcooler 12, and enters a hydrogen-rich tail gas channel I from the hydrogen-rich tail gas channel 9 from the heat exchanger 9, and enters a hydrogen-rich tail gas channel I from the hydrogen-rich tail gas channel I of A3 to enter a hydrogen-rich channel I, and enters a hydrogen-rich channel I of a heat exchanger 9 from the hydrogen-rich channel I, and is heated from the hydrogen-rich channel I;
The liquid at the bottom of the dehydrogenation tower 13 enters a demethanizer 16 after being throttled and depressurized by a throttle valve f32, the pressure of the demethanizer 16 is controlled to be 0.5MPa.G, the liquid at the bottom of the demethanizer 16 is subjected to rectification separation, the liquid at the bottom of the demethanizer is subjected to heat exchange and evaporation by a demethanizer bottom evaporator 15 to obtain methane-rich liquid, the methane-rich liquid enters a methane-rich gas channel IA 4 from the bottom of a heat exchanger 9 after being throttled and depressurized by a throttle valve g33, and the heated and rewarmed methane-rich gas is discharged from the top of the heat exchanger 9 and enters a methane outlet pipe 3;
The nitrogen-rich gas discharged from the upper part of the demethanizer 16 enters a nitrogen-rich channel ID 1 of a demethanizer top condenser 17, is cooled and condensed, returns to the top of the demethanizer 16, takes part in rectification by taking liquid as a reflux liquid at the top of the demethanizer 16, gas is discharged from the top of the demethanizer 16 and enters a denitrogenation tower 19, the pressure of the denitrogenation tower 19 is controlled at 0.48MPa.G, the nitrogen-rich gas at the upper part of the denitrogenation tower 19 enters a nitrogen-rich channel IIE 1 of a denitrogenation tower condenser 20 through rectification separation, is cooled and condensed, returns to the top of the denitrogenation tower 19, takes part in rectification by taking liquid as a reflux liquid at the top of the denitrogenation tower 19, takes part in rectification by taking gas out from the top of the denitrogenation tower 19 and is throttled to be reduced to 0.3MPa.G by a nitrogen-rich tail gas channel IIB 5 of the subcooler 12, the nitrogen-rich tail gas from the nitrogen-rich tail gas channel IIB 5 of the subcooler 12 enters a nitrogen-rich tail gas channel IA 5 from the bottom of the heat exchanger 9, and the nitrogen-rich tail gas after being heated and reheated enters a nitrogen-rich tail gas outlet pipe 4 from the top of the heat exchanger 9;
The liquid at the bottom of the denitrification tower 19 is subjected to heat exchange evaporation through the evaporator 18 at the bottom of the denitrification tower to obtain high-purity liquid argon, the liquid argon enters the liquid argon channel B4 of the subcooler 12, the subcooled liquid argon from the liquid argon channel B4 of the subcooler 12 enters the liquid argon outlet pipe 7, and the temperature of a liquid argon product is controlled at-178 ℃.
In this example, the mole percentages of the components in the synthesis ammonia tail gas and the mole percentages of the components in the resulting hydrogen-rich tail gas, methane, nitrogen-rich tail gas and liquid argon are shown in table 3 below:
TABLE 3 mole percent of the components
The variable efficiency of the compressor is 80%, the single machine energy consumption is the shaft power of the compressor divided by the standard square output of the argon product of the process per hour, the single machine energy consumption of the argon product of the process of the embodiment is 2.736kW/Nm 3, the single machine energy consumption of the argon product of the nitrogen expansion refrigeration process is 4.45kW/Nm 3, and the single machine energy consumption is reduced by 38.5%.
Claims (8)
1. The utility model provides a take device of nitrogen methane refrigeration cycle of precooling for retrieving argon and methane from synthetic ammonia tail gas which characterized in that: comprises a heat exchanger (9), a subcooler (12), a dehydrogenation tower (13), a demethanizer (16), a denitrification tower (19) and a precooler (11); wherein,
A dehydrogenation tower top condenser (14) is arranged at the upper part of the dehydrogenation tower (13);
the upper part and the lower part of the demethanizer (16) are respectively provided with a demethanizer top condenser (17) and a demethanizer bottom evaporator (15);
The upper part and the lower part of the denitrification tower (19) are respectively provided with a denitrification tower top condenser (20) and a denitrification tower bottom evaporator (18);
the heat exchanger (9) is internally provided with a synthesis ammonia tail gas channel I (A1), a synthesis ammonia tail gas channel II (A2), a hydrogen-rich tail gas channel I (A3), a methane-rich gas channel I (A4), a nitrogen-rich tail gas channel I (A5), a nitrogen methane forward flow channel I (A6), a nitrogen methane forward flow channel II (A7), a nitrogen methane forward flow channel III (A8) and a nitrogen methane return flow channel I (A9);
A hydrogen-rich tail gas channel II (B1), a nitrogen methane backflow channel II (B2), a nitrogen methane forward flow channel IV (B3), a liquid argon channel (B4) and a nitrogen-rich tail gas channel II (B5) are arranged in the subcooler (12);
a hydrogen-rich channel I (C1) and a nitrogen-methane channel I (C2) are arranged in the dehydrogenation tower top condenser (14);
A nitrogen-rich channel I (D1) and a nitrogen-methane channel II (D2) are arranged in the top condenser of the demethanizer (16);
a nitrogen-rich channel II (E1) and a nitrogen-methane channel III (E2) are arranged in the condenser at the top of the denitrification tower;
A synthesis ammonia tail gas channel III (F1), a nitrogen methane forward flow channel V (F2) and a precooling medium channel (F3) are arranged in the precooler (11);
the heat exchanger (9) is connected with a synthetic ammonia tail gas inlet pipe (1), a hydrogen-rich tail gas outlet pipe (2), a methane outlet pipe (3), a nitrogen-rich tail gas outlet pipe (4) and a nitrogen-methane circulating air inlet device; the subcooler (12) is connected with a liquid argon outlet pipe (7);
The nitrogen-methane circulation air inlet device comprises a nitrogen-methane compressor (8), wherein a nitrogen inlet pipe is connected to the inlet of the nitrogen-methane compressor (8), a nitrogen inlet pipe (5) and a methane inlet pipe (6) are connected to the nitrogen inlet pipe, a nitrogen outlet pipe is connected to the outlet of the nitrogen-methane compressor (8), the outlet of the nitrogen outlet pipe is connected with the inlet of a nitrogen positive flow channel I (A6), the outlet of the nitrogen positive flow channel I (A6) is connected with the inlet of a nitrogen positive flow channel V (F2), the outlet of the nitrogen positive flow channel V (F2) is connected with the inlet of a nitrogen positive flow channel II (A7), and the outlet of the nitrogen positive flow channel II (A7) is connected with the inlet pipe of a demethanizer tower bottom evaporator (15);
The inlet of the synthesis ammonia tail gas channel I (A1) is connected with the synthesis ammonia tail gas inlet pipe (1), the outlet of the synthesis ammonia tail gas channel I (A1) is connected with the inlet of the synthesis ammonia tail gas channel III (F1), the outlet of the synthesis ammonia tail gas channel III (F1) is connected with the inlet of the synthesis ammonia tail gas channel II (A2), and the outlet of the synthesis ammonia tail gas channel II (A2) is connected with the inlet at the lower part of the dehydrogenation tower (13);
The gas phase outlet at the top of the dehydrogenation tower (13) is connected with the inlet of a hydrogen-rich tail gas channel II (B1), the outlet of the hydrogen-rich tail gas channel II (B1) is connected with the inlet of a hydrogen-rich tail gas channel I (A3), and the outlet of the hydrogen-rich tail gas channel I (A3) is connected with a hydrogen-rich tail gas outlet pipe (2); the hydrogen-rich outlet at the upper part of the dehydrogenation tower (13) is connected with the inlet of a hydrogen-rich tail gas channel III (C1) of a dehydrogenation tower top condenser (14), the outlet of the hydrogen-rich tail gas channel III (C1) is connected with the inlet of reflux liquid at the upper part of the dehydrogenation tower (13), and the liquid phase outlet at the bottom of the dehydrogenation tower (13) is connected with the feeding port at the middle part of the demethanizer (16);
The nitrogen-rich outlet of the demethanizer (16) is connected with the inlet of a nitrogen-rich channel I (D1) of a demethanizer top condenser (17), the outlet of the nitrogen-rich channel I (D1) is connected with the reflux liquid inlet at the upper part of the demethanizer (16), the methane-rich liquid outlet at the bottom of the demethanizer (16) is connected with the inlet of a methane-rich gas channel I (A4), and the outlet of the methane-rich gas channel I (A4) is connected with a methane outlet pipe (3);
The outlet of the demethanizer bottom evaporator (15) is connected with an inlet pipe of the denitriding tower bottom evaporator (18), the outlet of the denitriding tower bottom evaporator (18) is connected with an inlet of a nitrogen methane positive flow channel III (A8), the outlet of the nitrogen methane positive flow channel III (A8) is respectively connected with a nitrogen methane return channel I (A9) and a nitrogen methane positive flow channel IV (B3), and the outlet of the nitrogen methane positive flow channel III (A8) is connected with the nitrogen methane positive flow channel IV (B3) through a branch pipe A (21); the outlet of the nitrogen methane backflow channel I (A9) is connected with a nitrogen methane feeding pipe of a nitrogen methane circulating air inlet device; the outlets of the nitrogen methane forward flow channel IV (B3) are respectively connected with inlets of a nitrogen methane channel I (C2), a nitrogen methane channel II (D2) and a nitrogen methane channel III (E2), the outlets of the nitrogen methane channel I (C2), the nitrogen methane channel II (D2) and the nitrogen methane channel III (E2) are respectively connected with an inlet of a nitrogen methane return flow channel II (B2), the outlet of the nitrogen methane return flow channel II (B2) is connected with an inlet of a nitrogen methane return flow channel I (A9), and the outlet of the nitrogen methane return flow channel I (A9) is connected with a nitrogen methane feed pipe of a nitrogen methane circulating air inlet device;
The nitrogen-rich outlet at the upper part of the denitrification tower (19) is connected with the inlet of a nitrogen-rich channel II (E1), the outlet of the nitrogen-rich channel II (E1) is connected with the inlet of reflux liquid at the upper part of the denitrification tower, the nitrogen-rich outlet at the top of the denitrification tower (19) is connected with the inlet of a nitrogen-rich tail gas channel II (B5), the outlet of the nitrogen-rich tail gas channel II (B5) is connected with the inlet of a nitrogen-rich tail gas channel I (A5), and the outlet of the nitrogen-rich tail gas channel I (A5) is connected with a nitrogen-rich tail gas outlet pipe (4);
the liquid argon outlet of the evaporator (18) at the bottom of the denitrification tower is connected with the inlet of a liquid argon channel (B4), and the outlet of the liquid argon channel (B4) is connected with a liquid argon outlet pipe (7);
a methane branch pipe (26) is connected between the methane outlet pipe (3) and the methane feeding pipe (6);
the pre-cooling compressor (10) is connected with a pre-cooling medium feeding pipe (25), the pre-cooling compressor (10) is connected with the pre-cooling medium channel (F3) through a circulating pipeline, and the pre-cooling medium feeding pipe (25) is connected to the circulating pipeline close to the inlet of the pre-cooling compressor (10).
2. The apparatus for recovering argon and methane from synthesis ammonia tail gas with precooled nitrogen-methane refrigeration cycle of claim 1, wherein: the control device is also included; the control device is electrically connected with a nitrogen methane compressor (8), a heat exchanger (9), a precooling compressor (10), a precooler (11), a subcooler (12), a dehydrogenation tower (13), a dehydrogenation tower top condenser (14), a demethanizer tower bottom evaporator (15), a demethanizer (16), a demethanizer tower top condenser (17), a denitrogenation tower bottom evaporator (18), a denitrogenation tower (19) and a denitrogenation tower top condenser (20) respectively.
3. The apparatus for recovering argon and methane from synthesis ammonia tail gas with precooled nitrogen-methane refrigeration cycle of claim 2, wherein: a throttle valve a (27) for throttling and reducing the pressure of the high-pressure nitrogen methane is arranged on a pipeline between the outlet of the nitrogen methane forward flow channel III (A8) and the inlet of the nitrogen methane return flow channel I (A9);
The outlet of the nitrogen methane positive flow channel IV (B3) is connected with the inlet of the nitrogen methane channel I (C2) through a branch pipe B (22), the outlet of the nitrogen methane positive flow channel IV (B3) is connected with the inlet of the nitrogen methane channel II (D2) through a branch pipe C (23), and the outlet of the nitrogen methane positive flow channel IV (B3) is connected with the inlet of the nitrogen methane channel III (E2) through a branch pipe D (24); the branch pipe B (22), the branch pipe C (23) and the branch pipe D (24) are respectively provided with a throttle valve B (28) for throttling and reducing the pressure of the nitrogen methane;
a throttle valve c (29) is arranged on an inlet pipeline of the precooling medium channel (F3);
a throttle valve d (30) is arranged on a pipeline between the outlet of the synthesis ammonia tail gas channel II (A2) and the inlet of the co-dehydrogenation tower (13);
A throttle valve e (31) for throttling and reducing the pressure of the hydrogen-rich tail gas is arranged between the top outlet of the dehydrogenation tower (13) and the inlet of the hydrogen-rich tail gas channel II (B1);
A pipeline between a liquid outlet at the bottom of the dehydrogenation tower (13) and an inlet of the demethanizer (16) is provided with a throttled valve f (32) for throttling and reducing the pressure of the liquid at the bottom of the dehydrogenation tower (13);
A throttle valve g (33) for throttling and reducing the pressure of the methane-rich liquid is arranged on an inlet pipeline of the methane-rich gas channel I (A4);
A throttle valve h (34) for throttling and reducing the pressure of the nitrogen-rich tail gas is arranged on an inlet pipeline of the nitrogen-rich tail gas channel II (B5);
a throttle valve i (35) for throttling and reducing pressure of the precooling medium is arranged on the precooling medium feeding pipe (25);
a throttle valve j (36) for throttling and reducing the pressure of the nitrogen and the methane is respectively arranged on the nitrogen feeding pipe (5) and the methane feeding pipe (6);
a throttle valve k (37) for throttling and reducing the pressure of methane is arranged on the methane branch pipe (26);
A throttle valve l (38) for throttling and reducing the pressure of the liquid argon is arranged on the liquid argon outlet pipe (7);
the throttle valve a (27), the throttle valve b (28), the throttle valve c (29), the throttle valve d (30), the throttle valve e (31), the throttle valve f (32), the throttle valve g (33), the throttle valve h (34), the throttle valve i (35), the throttle valve j (36), the throttle valve k (37) and the throttle valve l (38) are respectively electrically connected with a control device.
4. An apparatus for recovering argon and methane from synthesis ammonia tail gas with precooled nitrogen-methane refrigeration cycle as claimed in any one of claims 1-3 wherein: the connecting pipelines in the device are cold insulation pipelines.
5. A method for recovering argon and methane from synthesis ammonia tail gas, characterized by: the device for recovering argon and methane from the synthesis ammonia tail gas by using the precooled nitrogen-methane refrigeration cycle according to any one of claims 1-4; the method specifically comprises the following steps:
s1, determining a nitrogen-methane ratio according to a synthetic ammonia tail gas component, and then respectively introducing nitrogen and methane into a nitrogen-methane feed pipe of a nitrogen-methane compressor (8) through a nitrogen feed pipe (5) and a methane feed pipe (6) according to the ratio;
S2, the high-pressure nitrogen methane gas compressed by the nitrogen methane compressor (8) enters a nitrogen methane forward flow channel I (A6) of a heat exchanger (9) to be preliminarily cooled to 0 ℃ to minus 30 ℃, the nitrogen methane forward flow channel V (F2) entering a precooler (11) from the upper part after being preliminarily cooled is precooled to minus 10 ℃ to minus 40 ℃, the precooled high-pressure nitrogen methane gas returns to enter a nitrogen methane forward flow channel II (A7) of the heat exchanger (9) to be continuously cooled to minus 80 ℃ to minus 130 ℃, and then enters a demethanizer bottom evaporator (15) from the middle lower part after being preliminarily cooled;
The high-pressure nitrogen methane after heat exchange enters a demethanizer bottom evaporator (15) and enters a denitriding tower bottom evaporator (18), the nitrogen methane positive flow channel III (A8) entering the heat exchanger (9) is cooled to-140 ℃ to 160 ℃ after heat exchange, the high-pressure nitrogen methane exiting from the nitrogen methane positive flow channel III (A8) of the heat exchanger (9) is divided into two streams, the first stream enters a nitrogen methane return flow channel I (A9) of the heat exchanger (9) after throttling and depressurization, and the second stream enters a nitrogen methane positive flow channel IV (B3) of the subcooler (12) through a branch pipe A (21);
The high-pressure azotemia is supercooled to minus 170 ℃ to minus 180 ℃ through a azotemia positive flow channel IV (B3) of a supercooler (12), is separated into three azotemia which are throttled and decompressed respectively and then respectively enter a dehydrogenation tower top condenser (14), a demethanizer top condenser (17) and a azotemia channel I (C2), a azotemia channel II (D2) and a azotemia channel III (E2) of a denitrifying tower top condenser (20) to provide cold energy for the azotemia positive flow channel IV (B3), and the azotemia which comes from the dehydrogenation tower top condenser (14), the demethanizer top condenser (17) and the denitrifying tower top condenser (20) after being heated is converged and then enters a azotemia reflux channel II (B2) of the supercooler (12), providing cold energy for high-pressure nitrogen methane in a nitrogen methane positive flow channel IV (B3) of the subcooler (12), merging nitrogen methane from a nitrogen methane return channel II (B2) of the subcooler (12) and the first throttled nitrogen methane, entering a nitrogen methane return channel I (A9) of the heat exchanger (9), exchanging heat between low-temperature low-pressure nitrogen methane in the nitrogen methane return channel I (A9) and high-pressure nitrogen methane in a synthetic ammonia tail gas channel I (A1), a synthetic ammonia tail gas and a nitrogen methane positive flow channel I (A6), a nitrogen methane positive flow channel II (A7) and a nitrogen methane positive flow channel III (A8) of the heat exchanger (9), providing cold energy for the synthetic ammonia tail gas and the high-pressure nitrogen methane, the normal-temperature low-pressure nitrogen methane flowing out of the nitrogen methane backflow channel I (A9) of the heat exchanger (9) enters the nitrogen methane compressor (8) again, and compression cycle refrigeration is repeatedly carried out in the way;
S3, a precooling medium enters an inlet pipe of a precooling compressor (10) through a precooling medium feeding pipe (25), compressed liquid-phase precooling medium is throttled and depressurized and then enters a precooling medium channel (F3) of the precooler (11), the evaporation temperature of the precooling medium is controlled to be-20 ℃ to-43 ℃, the liquid-phase low-temperature low-pressure precooling medium in the precooling medium channel (F3) of the precooler (11) exchanges heat with the synthetic ammonia tail gas in a synthetic ammonia tail gas channel III (F1) and the nitrogen methane in a nitrogen methane forward flow channel V (F2) in the precooler (11) and provides cold energy, and the gas-phase low-temperature low-pressure precooling medium discharged from the precooler (11) enters the precooling compressor (10) again so as to repeatedly perform compression cycle refrigeration;
S4, the synthesis ammonia tail gas is initially cooled to 0 ℃ to minus 30 ℃ from a synthesis ammonia tail gas channel I (A1) of a heat exchanger (9) in a synthesis ammonia tail gas inlet pipe (1), is discharged from the heat exchanger (9) from the synthesis ammonia tail gas channel I (A1) and then enters a precooler (11) for precooling to minus 10 ℃ to minus 40 ℃, the precooled synthesis ammonia tail gas is returned to a synthesis ammonia tail gas channel II (A2) of the heat exchanger (9) for continuous cooling, is condensed to minus 140 ℃ to 160 ℃, the synthesis ammonia tail gas from the heat exchanger (9) is throttled and depressurized and then enters a dehydrogenation tower (13), hydrogen-rich gas from the upper part of the dehydrogenation tower (13) enters a hydrogen-rich gas channel I (C1) of a dehydrogenation tower top condenser (14) after being cooled and condensed, liquid is rectified as reflux liquid at the top of the dehydrogenation tower (13), the gas enters a hydrogen-rich channel II (B1) of a subcooler (12) after being discharged from the top of the dehydrogenation tower (13) and throttled and depressurized, the hydrogen-rich tail gas enters a hydrogen-rich tail gas channel II (B1) of the heat exchanger (9) from the heat exchanger (3) after being heated and the hydrogen-rich tail gas from the hydrogen-rich tail gas channel I (9) enters the hydrogen-rich tail gas channel I (3) after being heated and the hydrogen-rich tail gas channel II is separated, enters a hydrogen-rich tail gas outlet pipe (2);
The liquid at the bottom of the dehydrogenation tower (13) enters a demethanizer (16) after throttling and depressurization, the liquid at the bottom of the demethanizer (16) is subjected to rectification and separation, the methane-rich liquid is obtained after heat exchange and evaporation of the liquid at the bottom of the demethanizer (15), the methane-rich liquid enters a methane-rich gas channel I (A4) from the bottom of the heat exchanger (9) after throttling and depressurization, and the heated and rewarmed methane-rich gas is discharged from the top of the heat exchanger (9) and enters a methane outlet pipe (3);
The nitrogen-rich gas discharged from the upper part of the demethanizer (16) enters a nitrogen-rich channel I (D1) of a demethanizer top condenser (17), cooled and condensed and returns to the top of the demethanizer (16), liquid is taken as a nitrogen-rich tail gas channel II (B5) of the demethanizer (16) to participate in rectification, gas is discharged from the top of the demethanizer (16) and enters a denitrogenation tower (19), the nitrogen-rich gas is separated by rectification, the nitrogen-rich gas at the upper part of the denitrogenation tower (19) enters a nitrogen-rich channel II (E1) of a denitrogenation tower condenser (20), cooled and condensed and returns to the top of the denitrogenation tower (19), the liquid is taken as a nitrogen-rich tail gas channel II (B5) of the subcooler (12) after being discharged from the top of the denitrogenation tower (19) and throttled and depressurized, the nitrogen-rich tail gas from the subcooler (12) enters a nitrogen-rich tail gas channel I (A5) from the bottom of the heat exchanger (9), and the heated and rewarmed nitrogen-rich tail gas enters a nitrogen-rich outlet pipe (4) from the top of the heat exchanger (9);
The liquid at the bottom of the denitrification tower (19) is subjected to heat exchange evaporation through an evaporator (18) at the bottom of the denitrification tower to obtain high-purity liquid argon, the liquid argon enters a liquid argon channel (B4) of the subcooler (12), the subcooled liquid argon from the liquid argon channel (B4) of the subcooler (12) enters a liquid argon outlet pipe (7), and the temperature of a liquid argon product is controlled between-170 ℃ and-178 ℃.
6. The method for recovering argon and methane from ammonia synthesis tail gas according to claim 5, wherein: the purified synthesis ammonia tail gas comprises: hydrogen, nitrogen, methane and argon, and the molar ratio of argon to methane in the tail gas of the synthetic ammonia is as follows: argon: 4.0 to 12.0 percent of methane: 6.0 to 35 percent.
7. The method for recovering argon and methane from ammonia synthesis tail gas according to claim 5, wherein: the pressure of the synthesis ammonia tail gas channel I (A1) entering the heat exchanger (9) is controlled to be 4.0-6.0 MPa.
The pressure of the low-pressure nitrogen methane gas flowing back from the nitrogen methane backflow channel I (A9) into the nitrogen methane compressor (8) is controlled to be 0.1-0.25 MPa.
The outlet pressure of the nitrogen methane compressor (8) is controlled to be 2.0-5.0 MPa.
The pressure of the dehydrogenation tower (13) is controlled to be 1.5-4.0 MPa.
The pressure of the demethanizer (16) is controlled to be 0.5-1.0 MPa.G;
The pressure of the denitrification tower (19) is controlled to be 0.5-1.0 MPa.
8. The method for recovering argon and methane from ammonia synthesis tail gas according to claim 5, wherein: the precooling medium adopts ammonia, or propane, or freon.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102419071A (en) * | 2011-12-12 | 2012-04-18 | 杭州中泰深冷技术股份有限公司 | Separation and recycling device and recycling method for methane and argon in synthetic ammonia relief gas |
| CN104567276A (en) * | 2014-12-30 | 2015-04-29 | 杭州凯德空分设备有限公司 | Device and technological method for producing LNG (liquefied natural gas) by recycling ammonia tail gas |
| CN104986734A (en) * | 2015-06-24 | 2015-10-21 | 杭州中泰深冷技术股份有限公司 | Synthesis ammonia and synthesis gas self-circulation cryogenic separation purifying device and purifying method thereof |
| CN105423701A (en) * | 2015-11-17 | 2016-03-23 | 辽宁中集哈深冷气体液化设备有限公司 | Method for preparing synthetic natural gas (SNG) through coke-oven gas cryogenic separating |
| CN217900304U (en) * | 2021-11-30 | 2022-11-25 | 四川蜀道装备科技股份有限公司 | Device for recovering argon and methane from synthetic ammonia tail gas |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102419071A (en) * | 2011-12-12 | 2012-04-18 | 杭州中泰深冷技术股份有限公司 | Separation and recycling device and recycling method for methane and argon in synthetic ammonia relief gas |
| CN104567276A (en) * | 2014-12-30 | 2015-04-29 | 杭州凯德空分设备有限公司 | Device and technological method for producing LNG (liquefied natural gas) by recycling ammonia tail gas |
| CN104986734A (en) * | 2015-06-24 | 2015-10-21 | 杭州中泰深冷技术股份有限公司 | Synthesis ammonia and synthesis gas self-circulation cryogenic separation purifying device and purifying method thereof |
| CN105423701A (en) * | 2015-11-17 | 2016-03-23 | 辽宁中集哈深冷气体液化设备有限公司 | Method for preparing synthetic natural gas (SNG) through coke-oven gas cryogenic separating |
| CN217900304U (en) * | 2021-11-30 | 2022-11-25 | 四川蜀道装备科技股份有限公司 | Device for recovering argon and methane from synthetic ammonia tail gas |
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