CN110054164B - Concentrated recovery system of dilute sulfuric acid - Google Patents
Concentrated recovery system of dilute sulfuric acid Download PDFInfo
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- CN110054164B CN110054164B CN201910435634.2A CN201910435634A CN110054164B CN 110054164 B CN110054164 B CN 110054164B CN 201910435634 A CN201910435634 A CN 201910435634A CN 110054164 B CN110054164 B CN 110054164B
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- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 title claims abstract description 366
- 238000011084 recovery Methods 0.000 title claims abstract description 46
- 239000007788 liquid Substances 0.000 claims description 64
- 238000010438 heat treatment Methods 0.000 claims description 49
- 238000006298 dechlorination reaction Methods 0.000 claims description 43
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 37
- 239000000460 chlorine Substances 0.000 claims description 37
- 229910052801 chlorine Inorganic materials 0.000 claims description 37
- 239000002699 waste material Substances 0.000 claims description 24
- 239000003513 alkali Substances 0.000 claims description 19
- 238000010521 absorption reaction Methods 0.000 claims description 11
- 238000007599 discharging Methods 0.000 claims description 7
- 238000009833 condensation Methods 0.000 claims description 6
- 230000005494 condensation Effects 0.000 claims description 6
- 238000005086 pumping Methods 0.000 claims description 3
- 239000003795 chemical substances by application Substances 0.000 claims description 2
- 238000007781 pre-processing Methods 0.000 claims 2
- 238000000034 method Methods 0.000 abstract description 26
- 238000005265 energy consumption Methods 0.000 abstract description 17
- 239000012141 concentrate Substances 0.000 abstract description 4
- 239000007789 gas Substances 0.000 description 33
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 20
- 238000001704 evaporation Methods 0.000 description 14
- 230000008901 benefit Effects 0.000 description 11
- 238000004064 recycling Methods 0.000 description 9
- 238000002347 injection Methods 0.000 description 8
- 239000007924 injection Substances 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- 230000008020 evaporation Effects 0.000 description 7
- 239000002918 waste heat Substances 0.000 description 7
- 238000009835 boiling Methods 0.000 description 6
- 239000010808 liquid waste Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 238000001035 drying Methods 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 3
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 3
- 238000012856 packing Methods 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- 239000002351 wastewater Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000003337 fertilizer Substances 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000003889 chemical engineering Methods 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 239000007806 chemical reaction intermediate Substances 0.000 description 1
- 239000012459 cleaning agent Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 239000012024 dehydrating agents Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000004043 dyeing Methods 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000006053 organic reaction Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000007639 printing Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000003507 refrigerant Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D1/00—Evaporating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D1/00—Evaporating
- B01D1/30—Accessories for evaporators ; Constructional details thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/10—Vacuum distillation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/143—Fractional distillation or use of a fractionation or rectification column by two or more of a fractionation, separation or rectification step
- B01D3/148—Fractional distillation or use of a fractionation or rectification column by two or more of a fractionation, separation or rectification step in combination with at least one evaporator
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/68—Halogens or halogen compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/77—Liquid phase processes
- B01D53/78—Liquid phase processes with gas-liquid contact
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/69—Sulfur trioxide; Sulfuric acid
- C01B17/88—Concentration of sulfuric acid
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/69—Sulfur trioxide; Sulfuric acid
- C01B17/90—Separation; Purification
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/20—Halogens or halogen compounds
- B01D2257/206—Organic halogen compounds
- B01D2257/2064—Chlorine
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Analytical Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Biomedical Technology (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
- Heat Treatment Of Water, Waste Water Or Sewage (AREA)
Abstract
The invention relates to the technical field of dilute sulfuric acid concentration, in particular to a dilute sulfuric acid concentration recovery system, which comprises a dilute sulfuric acid preheating device, a vacuum concentration device and a concentrated sulfuric acid recovery device, wherein the dilute sulfuric acid preheating device comprises a heat exchanger and a first heater, the vacuum concentration device comprises a concentration kettle, a first inlet of the heat exchanger is used for being connected with a dilute sulfuric acid source, a first outlet of the heat exchanger is communicated with an inlet of the first heater, an outlet of the first heater is communicated with an inlet of the concentration kettle, an outlet of the concentration kettle is communicated with a second inlet of the heat exchanger, and a second outlet of the heat exchanger is communicated with the concentrated sulfuric acid recovery device. The secondary preheating device and the vacuum concentration device effectively concentrate the dilute sulfuric acid, have short flow and less equipment, ensure that the mass fraction of the concentrated sulfuric acid formed after concentration reaches the required process standard while ensuring that the temperature required by concentration and recovery of the dilute sulfuric acid is reached, greatly reduce energy consumption, are efficient and practical, and enhance the application range and stability of the process.
Description
Technical Field
The invention relates to the technical field of dilute sulfuric acid concentration, in particular to a dilute sulfuric acid concentration and recovery system.
Background
At present, sulfuric acid is an important basic chemical raw material, has wide application in the industries of chemical engineering, steel and the like, and is commonly used as a dehydrating agent, a reaction intermediate, a cleaning agent, a catalyst and the like in industry. The sulfuric acid used is usually reduced in concentration or becomes dilute sulfuric acid containing impurities, and cannot be used for production any more, so that the sulfuric acid used in many industrial processes is finally disposed in a waste acid mode or is discharged after being simply treated, and serious problems of resource waste and environmental pollution are caused.
Along with the development of chemical industry and the requirement for environmental protection, the dilute sulfuric acid is generally concentrated, recovered and recycled in the chemical industry. In the past, sulfuric acid concentration processes, such as pot concentration, combustion concentration, high-temperature concentration, low-temperature concentration and the like, are also available, but due to the strong corrosiveness of sulfuric acid, the high-temperature concentration process is often not feasible, and further due to the high energy consumption of sulfuric acid concentration, the recovery value is low, so that most users prefer to treat the sulfuric acid as waste, and some enterprises directly discharge the sulfuric acid even without treatment, thereby severely polluting the environment. The low-temperature concentration method is only suitable for concentrating dilute sulfuric acid with the mass fraction concentration of less than 60%, and the mass fraction concentration of the concentrated sulfuric acid is not more than 60%, so that the method cannot meet the requirements of a plurality of processes.
Currently, the chlorine-alkali enterprises and the PVC enterprises mainly sell the chlorine-drying waste sulfuric acid to the enterprises producing chemical fertilizers for producing chemical fertilizers or for neutralizing carbide sludge, so that the chlorine-alkali enterprises and the PVC enterprises convert the chlorine-drying waste sulfuric acid into gypsum for sale. The chlorine drying waste acid is dissolved with about 0.2 percent of chlorine, and the hydrogen chloride drying waste sulfuric acid contains about 0.13 percent of hydrogen chloride gas, so that the utilization of the obtained dilute sulfuric acid is limited, and the dilute sulfuric acid has stronger corrosiveness than the finished sulfuric acid, and the volatilized chlorine and hydrogen chloride seriously pollute the environment in the transportation and use processes.
Disclosure of Invention
First, the technical problem to be solved
The invention aims to solve the technical problems that the existing dilute sulfuric acid concentration and recovery system is high in energy consumption, the concentrated sulfuric acid mass fraction does not reach the standard, and the process requirement cannot be met.
(II) technical scheme
In order to solve the technical problems, the invention provides a dilute sulfuric acid concentration and recovery system, which comprises a dilute sulfuric acid preheating device, a vacuum concentration device and a concentrated sulfuric acid recovery device, wherein the dilute sulfuric acid preheating device comprises a heat exchanger and a first heater, the vacuum concentration device comprises a concentration kettle, a first inlet of the heat exchanger is used for being connected with a dilute sulfuric acid source, a first outlet of the heat exchanger is communicated with an inlet of the first heater, an outlet of the first heater is communicated with an inlet of the concentration kettle, an outlet of the concentration kettle is communicated with a second inlet of the heat exchanger, and a second outlet of the heat exchanger is communicated with the concentrated sulfuric acid recovery device.
The concentrating kettle comprises a rectifying concentrating section and a heating concentrating section which are sequentially arranged along the flow direction of the dilute sulfuric acid in the concentrating kettle, wherein an inlet of the rectifying concentrating section is communicated with an outlet of the first heater, a liquid outlet of the rectifying concentrating section is communicated with an inlet of the heating concentrating section, and an outlet of the heating concentrating section is communicated with a second inlet of the heat exchanger.
Wherein, heating element is equipped with to the bottom of heating concentrated section.
The vacuum concentration device further comprises a condenser and a condensation tank, wherein an inlet of the condenser is communicated with a gas outlet of the rectification concentration section, and an outlet of the condenser is communicated with an inlet of the condensation tank.
The device comprises a condensing tank, a liquid waste treatment device, a detector and an alkali injection pipeline, wherein the outlet of the condensing tank is communicated with the liquid waste treatment device, the liquid waste treatment device is provided with the detector and the alkali injection pipeline, the detector is used for detecting the pH value of liquid waste in the liquid waste treatment device, and the alkali injection pipeline is used for injecting alkali into the liquid waste treatment device.
The condensing tank is provided with a liquid ring vacuum pump, the liquid ring vacuum pump is used for enabling the vacuum concentration device to be in a negative pressure state, a liquid inlet of the liquid ring vacuum pump is connected with an outlet of the condensing tank, and a liquid outlet of the liquid ring vacuum pump is connected with the waste liquid treatment device.
The concentrated sulfuric acid recovery device comprises a first cooler, and a second outlet of the heat exchanger is communicated with the first cooler.
The device comprises a heat exchanger, and is characterized by further comprising a dilute sulfuric acid pretreatment device, wherein the dilute sulfuric acid pretreatment device comprises a dechlorination tower, a liquid inlet for introducing chlorine-containing dilute sulfuric acid and a gas outlet for discharging chlorine are arranged at the top of the dechlorination tower, a gas inlet for introducing compressed gas and a liquid outlet for discharging dilute sulfuric acid are arranged at the bottom of the dechlorination tower, and the liquid outlet is communicated with a first inlet of the heat exchanger.
The dilute sulfuric acid pretreatment device further comprises a circulating pump and a second heater, wherein the circulating pump is connected with a liquid outlet of the dechlorination tower and used for pumping dilute sulfuric acid flowing out of the dechlorination tower back to the dechlorination tower, and the second heater is arranged on a pipeline which is communicated with a liquid inlet of the dechlorination tower through the circulating pump.
The dilute sulfuric acid pretreatment device further comprises an exhaust gas treatment device, wherein the exhaust gas treatment device comprises a second cooler and a chlorine absorption tank, an inlet of the second cooler is communicated with an air outlet of the dechlorination tower, an outlet of the second cooler is connected with the chlorine absorption tank, and dilute alkali liquor is contained in the chlorine absorption tank.
(III) beneficial effects
The technical scheme of the invention has the following advantages: according to the dilute sulfuric acid concentration and recovery system, dilute sulfuric acid enters the dilute sulfuric acid preheating device for preheating, first-stage heating is carried out through the heat exchanger, second-stage heating is carried out through the first heater, the preheating device for two-stage heating can fully improve the temperature of water in the dilute sulfuric acid, the subsequent concentration heating energy consumption is reduced, dilute sulfuric acid preheated to a certain temperature enters the concentration kettle of the vacuum concentration device, the concentration kettle keeps negative pressure operation, the temperature required by evaporation can be effectively reduced due to the fact that the dilute sulfuric acid is concentrated in a vacuum state, the heating energy consumption of the concentration kettle is further reduced, the dilute sulfuric acid is continuously heated and heated in the flowing process of the concentration kettle, the water in the dilute sulfuric acid is continuously gasified and discharged, concentrated to form concentrated sulfuric acid, the concentrated sulfuric acid is discharged into the heat exchanger again through the outlet of the concentration kettle and exchanges heat with the dilute sulfuric acid entering the heat exchanger, so that first-stage heating is provided for the dilute sulfuric acid, the waste heat is fully utilized, the energy consumption is saved, and finally the concentrated sulfuric acid is flowed into the concentrated sulfuric acid recovery device to complete the concentration and recovery of the dilute sulfuric acid. The secondary preheating device and the vacuum concentration device effectively concentrate the dilute sulfuric acid, have short flow and less equipment, ensure that the mass fraction of the concentrated sulfuric acid formed after concentration reaches the required process standard while reaching the required temperature for concentrating and recycling the dilute sulfuric acid, greatly reduce the energy consumption, are efficient and practical, enhance the application range and the stability of the process, reduce the construction cost and the operation cost of a dilute sulfuric acid concentrating and recycling system, improve the economic benefit and the social benefit of dilute sulfuric acid recycling, and have wide adaptability.
In addition to the technical problems, features of the constituent technical solutions and advantages brought by the technical features of the technical solutions described above, other technical features of the present invention and advantages brought by the technical features of the technical solutions, further description will be made with reference to the accompanying drawings.
Drawings
FIG. 1 is a schematic diagram of a dilute sulfuric acid concentration recovery system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a dilute sulfuric acid pretreatment device of a dilute sulfuric acid concentration recovery system according to an embodiment of the present invention.
In the figure: 1: a dilute sulfuric acid preheating device; 2: a vacuum concentration device; 3: a concentrated sulfuric acid recovery device; 4: a waste liquid treatment device; 5: a dilute sulfuric acid pretreatment device; 6: chlorine-containing dilute sulfuric acid; 7: compressing the gas; 11: a heat exchanger; 12: a first heater; 21: concentrating the kettle; 22: a condenser; 23: a condensing tank; 24: a liquid ring vacuum pump; 31: a first cooler; 41: a detector; 42: an alkali injection pipeline; 51: a dechlorination tower; 52: a circulation pump; 53: a second heater; 54: an exhaust gas treatment device; 211: rectifying and concentrating the section; 212: heating and concentrating the section; 213: a heating assembly; 541: a second cooler; 542: a chlorine absorption tank.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Furthermore, in the description of the present invention, unless otherwise indicated, the meaning of "a plurality", "a plurality of groups" means two or more, and the meaning of "a plurality", "a plurality of roots", "a plurality of groups" means one or more.
As shown in fig. 1, the dilute sulfuric acid concentration and recovery system provided by the embodiment of the invention comprises a dilute sulfuric acid preheating device 1, a vacuum concentration device 2 and a concentrated sulfuric acid recovery device 3, wherein the dilute sulfuric acid preheating device 1 comprises a heat exchanger 11 and a first heater 12, the vacuum concentration device 2 comprises a concentration kettle 21, a first inlet of the heat exchanger 11 is used for being connected with a dilute sulfuric acid source, a first outlet of the heat exchanger 11 is communicated with an inlet of the first heater 12, an outlet of the first heater 12 is communicated with an inlet of the concentration kettle 21, an outlet of the concentration kettle 21 is communicated with a second inlet of the heat exchanger 11, and a second outlet of the heat exchanger 11 is communicated with the concentrated sulfuric acid recovery device 3.
According to the dilute sulfuric acid concentration and recovery system, dilute sulfuric acid enters the dilute sulfuric acid preheating device for preheating, first-stage heating is carried out through the heat exchanger, second-stage heating is carried out through the first heater, the preheating device for two-stage heating can fully improve the temperature of water in the dilute sulfuric acid, the subsequent concentration heating energy consumption is reduced, dilute sulfuric acid preheated to a certain temperature enters the concentration kettle of the vacuum concentration device, the concentration kettle keeps negative pressure operation, the temperature required by evaporation can be effectively reduced due to the fact that the dilute sulfuric acid is concentrated in a vacuum state, the heating energy consumption of the concentration kettle is further reduced, the dilute sulfuric acid is continuously heated and heated in the flowing process of the concentration kettle, the water in the dilute sulfuric acid is continuously gasified and discharged, concentrated to form concentrated sulfuric acid, the concentrated sulfuric acid is discharged into the heat exchanger again through the outlet of the concentration kettle and exchanges heat with the dilute sulfuric acid entering the heat exchanger, so that first-stage heating is provided for the dilute sulfuric acid, the waste heat is fully utilized, the energy consumption is saved, and finally the concentrated sulfuric acid is flowed into the concentrated sulfuric acid recovery device to complete the concentration and recovery of the dilute sulfuric acid. The secondary preheating device and the vacuum concentration device effectively concentrate the dilute sulfuric acid, have short flow and less equipment, ensure that the mass fraction of the concentrated sulfuric acid formed after concentration reaches the required process standard while reaching the required temperature for concentrating and recycling the dilute sulfuric acid, greatly reduce the energy consumption, are efficient and practical, enhance the application range and the stability of the process, reduce the construction cost and the operation cost of a dilute sulfuric acid concentrating and recycling system, improve the economic benefit and the social benefit of dilute sulfuric acid recycling, and have wide adaptability.
In this embodiment, the heat exchanger may be a feeding and discharging heat exchanger, the first heater may be a heating mode such as hot water, low-pressure steam or medium-pressure steam, and if there is other available waste heat in the device, the first heater may be used with priority.
In one embodiment, the concentrating tank 21 comprises a rectifying concentrating section 211 and a heating concentrating section 212 which are sequentially arranged along the flow direction of the dilute sulfuric acid in the concentrating tank, wherein an inlet of the rectifying concentrating section 211 is communicated with an outlet of the first heater 12, a liquid outlet of the rectifying concentrating section 211 is communicated with an inlet of the heating concentrating section 212, and an outlet of the heating concentrating section 212 is communicated with a second inlet of the heat exchanger 11. The dilute sulfuric acid is preheated in the dilute sulfuric acid preheating device and then enters the concentration kettle, the concentration kettle can further heat the dilute sulfuric acid to remove water and impurities, the dilute sulfuric acid flows to the heating concentration section from the rectification concentration section, part of water in the dilute sulfuric acid is gasified and discharged under the negative pressure condition, and the primarily concentrated dilute sulfuric acid obtained in the rectification concentration section enters the heating concentration section to be continuously heated and concentrated, so that the load of the concentration kettle can be reduced, and the waste heat can be fully utilized to save energy consumption. In this embodiment, the rectifying and concentrating section is located at the upper part of the heating and concentrating section, the rectifying and concentrating section may be a rectifying tower, the heating and concentrating section may be an evaporating kettle, the dilute sulfuric acid enters the rectifying tower after being preheated and heated, part of the water in the dilute sulfuric acid is gasified and discharged, the rest liquid phase material flows downwards along the rectifying tower and enters the evaporating kettle, the liquid phase material is continuously heated and heated in the moving process, the water is continuously gasified, the gas phase material moves upwards along the rectifying tower and contacts with the dilute sulfuric acid running downwards to perform heat mass exchange, the gasified sulfuric acid and the decomposed SO 3 are absorbed and brought back to the evaporating kettle, the concentration of the sulfuric acid in the evaporating kettle is continuously increased in the moving process, and finally the concentrated sulfuric acid reaching the required concentration flows out from the outlet at the bottom of the evaporating kettle and enters the heat exchanger through the second inlet of the heat exchanger, and is discharged to the concentrated sulfuric acid recovery device through the second outlet of the heat exchanger after heat exchange with the dilute sulfuric acid fed.
In this embodiment, the rectifying tower may be a plate tower or a packed tower, preferably a ceramic packed tower, and the plate tower is a floating valve tray, a sieve tray, or a bubble cap tray, and the number of trays is 3-8, preferably 4-6. The packing height of the packed tower is 500-2000 mm, preferably 800-1200 mm. The evaporating kettle is a horizontal container, a heating pipe is arranged in the evaporating kettle, and the heating capacity is gradually enhanced along the liquid flow direction.
In one embodiment, the bottom of the heated concentrating section 212 is provided with a heating assembly 213. The bottom of the heating concentration section is provided with a heating component, so that a certain gradual temperature gradient is formed from the bottom of the heating concentration section to the top of the rectifying concentration section, and the temperature provided by the rectifying concentration section is matched with the water gasified in the rectifying concentration section, so that the temperature balance is achieved in the concentration kettle. In this embodiment, the heating component may be a heating pipe, and a heating mode of high-temperature heat conduction oil or electric heating is adopted, and if there is other available waste heat in the device, the utilization may be prioritized.
In one embodiment, the vacuum concentration device 2 further comprises a condenser 22 and a condensing tank 23, wherein an inlet of the condenser 22 is communicated with a gas outlet of the rectifying and concentrating section 211, and an outlet of the condenser 22 is communicated with an inlet of the condensing tank 23. After the dilute sulfuric acid is heated in a rectifying and concentrating section of a concentrating kettle, part of water in the dilute sulfuric acid is gasified and discharged into a condenser from a gas outlet at the top of the rectifying and concentrating section, the condenser exchanges heat with the gas to form liquid, and the liquid flows into a condensing tank through a condenser outlet to be further subjected to exothermic condensation. In this embodiment, the condenser is a gas phase condenser, and the condenser and the condensing tank may use refrigerant media such as circulating water or chilled water.
In one embodiment, the dilute sulfuric acid concentration and recovery system further comprises a waste liquid treatment device 4, an outlet of the condensing tank 23 is communicated with the waste liquid treatment device 4, a detector 41 and an alkali injection pipeline 42 are arranged on the waste liquid treatment device 4, the detector 41 is used for detecting the pH value of waste liquid in the waste liquid treatment device 4, and the alkali injection pipeline 42 is used for injecting alkali into the waste liquid treatment device 4. The liquid discharged from the condensing tank enters a waste liquid treatment device, the waste liquid treatment device recovers and treats the waste water discharged from the dilute sulfuric acid concentration process, a detector is arranged on a non-treatment device to detect the pH value of the entered waste water, ammonia water or alkali liquor is injected into the waste liquid treatment device through an alkali injection pipeline to neutralize acid and alkali, and the waste water is orderly discharged into a sewage treatment system to be treated after being neutralized to be up to standard. In the embodiment, the detector can adopt a PH on-line monitoring system to control the injection quantity of the alkaline agent in real time, thereby ensuring the neutrality of the discharged water and not affecting the sewage treatment system.
In one embodiment, the condensing tank 23 is provided with a liquid ring vacuum pump 24 for forming a negative pressure state in the vacuum concentration device 2, a liquid inlet of the liquid ring vacuum pump 24 is connected with an outlet of the condensing tank 23, and a liquid outlet of the liquid ring vacuum pump 24 is connected with the waste liquid treatment device 4. The evaporation temperature of the concentrated sulfuric acid under normal pressure is over 300 ℃, and the evaporation temperature of the concentrated sulfuric acid under vacuum can be reduced by about 60-80 ℃, so that the equipment material selection and the service life are facilitated, the operation energy consumption can be reduced, and the economic benefit is improved. For example, 85% concentrated sulfuric acid has an atmospheric boiling point of 227 ℃ and a boiling point of about 160 ℃ at a pressure of 10kPa absolute; 90% concentrated sulfuric acid has an atmospheric boiling point of 259℃and a boiling point of about 190℃at 10kPa absolute pressure, and 95% concentrated sulfuric acid has an atmospheric boiling point of 301℃and a boiling point of about 230℃at 10kPa absolute pressure. Therefore, the liquid ring vacuum pump is connected with the condensing tank, so that the condensing kettle, the gas phase condenser, the condensing tank and the air flow in the liquid ring vacuum pump form a passage, the liquid ring vacuum pump provides required vacuum conditions for the vacuum condensing device, the vacuum operation of the condensing kettle is ensured, and the operation temperature and the material selection difficulty are effectively reduced. The liquid ring medium of the liquid ring vacuum pump is preferably evaporation condensate water separated from the condensing tank, so that on one hand, the vacuum degree can be ensured, and on the other hand, the water evaporated in the concentration process and a small amount of carried process medium can be utilized and recovered, and the environment pollution caused by external pollution is avoided.
In one embodiment, the concentrated sulfuric acid recovery apparatus 3 includes a first cooler 31, and the second outlet of the heat exchanger 11 communicates with the first cooler 31. The concentrated sulfuric acid discharged from the heating concentration section flows into a first cooler of the concentrated sulfuric acid recovery device after heat exchange with the feed dilute sulfuric acid through a heat exchanger, and enters a concentrated sulfuric acid storage tank after further circulating water cooling through the first cooler to be recycled as raw materials of a process system.
In one embodiment, as shown in fig. 2, the dilute sulfuric acid concentration and recovery system further comprises a dilute sulfuric acid pretreatment device 5, the dilute sulfuric acid pretreatment device 5 comprises a dechlorination tower 51, a liquid inlet for introducing chlorine-containing dilute sulfuric acid 6 and a gas outlet for discharging chlorine are arranged at the top of the dechlorination tower 51, a liquid inlet for introducing compressed gas 7 and a liquid outlet for discharging dilute sulfuric acid are arranged at the bottom of the dechlorination tower, and the liquid outlet is communicated with the first inlet of the heat exchanger 11. According to different sources of the dilute sulfuric acid, different pretreatment processes are selected, mainly impurities in the dilute sulfuric acid are removed, stable operation of a subsequent system is ensured, in the embodiment, the dilute sulfuric acid is subjected to dechlorination treatment before entering the dilute sulfuric acid preheating device, and then enters the evaporation concentration system. The chlorine-containing dilute sulfuric acid enters the dechlorination tower from a liquid inlet at the upper side of the dechlorination tower, compressed gas enters the dechlorination tower from an air inlet at the lower side of the middle of the dechlorination tower, the chlorine-containing dilute sulfuric acid flows downwards, the compressed gas flows upwards, the compressed gas and the compressed gas are in reverse contact, chlorine in the chlorine-containing dilute sulfuric acid is taken away by the compressed gas, the chlorine-containing dilute sulfuric acid is discharged from an air outlet at the top of the dechlorination tower, and the dilute sulfuric acid qualified in dechlorination is discharged from a liquid outlet at the bottom of the dechlorination tower, so that dechlorination treatment of the dilute sulfuric acid is completed.
In this embodiment, the compressed gas may be nitrogen or air, and the dechlorination tower may be provided with packing or trays, preferably ceramic or resin bulk packing. The positions of the liquid inlet and the air inlet in the dechlorination tower are provided with the distributor, so that the chlorine-containing dilute sulfuric acid and the compressed air can be more uniformly distributed and in scattered contact after entering the tower, and the dechlorination effect is improved.
In one embodiment, the dilute sulfuric acid pretreatment device 5 further comprises a circulating pump 52 and a second heater 53, wherein the circulating pump 52 is connected with the liquid outlet of the dechlorination tower 51 and is used for pumping dilute sulfuric acid flowing out of the dechlorination tower 51 back to the dechlorination tower 51, and the second heater 53 is arranged on a pipeline of the circulating pump 52 communicated with the liquid inlet of the dechlorination tower 51. In order to ensure the dechlorination effect of the chlorine-containing dilute sulfuric acid, an external circulating pump is additionally arranged, the dilute sulfuric acid flowing out of a liquid outlet at the bottom of the dechlorination tower is pumped back to a liquid inlet at the top of the dechlorination tower, and the dilute sulfuric acid pumped out by the circulating pump is heated before entering the dechlorination tower through a second heater, so that the dilute sulfuric acid is dechlorinated thoroughly after repeatedly entering the dechlorination tower and repeatedly reversely contacting with compressed gas. In this embodiment, the heating medium of the second heater may be hot water or heat exchanged with other waste heat, and is heated to 50-100 ℃, preferably 60-80 ℃.
In one embodiment, the dilute sulfuric acid pretreatment device 5 further comprises an exhaust gas treatment device 54, the exhaust gas treatment device 54 comprises a second cooler 541 and a chlorine absorbing tank 542, an inlet of the second cooler 541 is communicated with an air outlet of the dechlorination tower 51, and an outlet of the second cooler 541 is connected with the chlorine absorbing tank 542, and the chlorine absorbing tank 542 contains dilute lye. After the chlorine-containing dilute sulfuric acid is in opposite flushing contact with the compressed air, the chlorine-containing gas is discharged from the air outlet of the dechlorination tower to enter the second cooler, after the second cooler performs heat exchange cooling on the chlorine-containing gas, the chlorine-containing gas enters the chlorine absorption tank, the dilute alkali solution and other chlorine absorbing substances are contained in the chlorine absorption tank, the chlorine-containing gas is purified into purified gas through the dechlorination effect of the chlorine absorption tank, and the exhaust gas is discharged from the chlorine absorption tank to complete the exhaust gas treatment, so that the environment is not polluted by the discharged chlorine gas, and the environment protection of the dilute sulfuric acid pretreatment work is ensured.
Different pretreatment processes can be adopted for different waste dilute sulfuric acid, for example, for the medicine or printing and dyeing industry, the waste dilute sulfuric acid generated by the organic reaction can be subjected to oxidation treatment firstly; the waste dilute sulfuric acid in the steel industry is subjected to filtration, impurity removal and the like.
In summary, according to the dilute sulfuric acid concentration and recovery system disclosed by the invention, dilute sulfuric acid enters the dilute sulfuric acid preheating device for preheating, first-stage heating is performed through the heat exchanger, second-stage heating is performed through the first heater, the preheating device for two-stage heating can fully raise the temperature of water in the dilute sulfuric acid, the subsequent concentration heating energy consumption is reduced, dilute sulfuric acid preheated to a certain temperature enters the concentration kettle of the vacuum concentration device, the concentration kettle keeps negative pressure operation, the temperature required by evaporation can be effectively reduced by concentrating the dilute sulfuric acid in a vacuum state, so that the heating energy consumption of the concentration kettle is further reduced, the dilute sulfuric acid is continuously heated and heated in the flowing process of the concentration kettle, the water in the dilute sulfuric acid is continuously gasified and discharged, and concentrated to form concentrated sulfuric acid, and then the concentrated sulfuric acid is discharged into the heat exchanger again through the outlet of the concentration kettle for heat exchange with the dilute sulfuric acid entering the heat exchanger, so that the first-stage heating is provided for the dilute sulfuric acid, the waste heat is fully utilized, the energy consumption is saved, and finally the concentrated sulfuric acid is flowed into the concentrated sulfuric acid recovery device to complete the concentration and recovery of the dilute sulfuric acid. The secondary preheating device and the vacuum concentration device effectively concentrate the dilute sulfuric acid, have short flow and less equipment, ensure that the mass fraction of the concentrated sulfuric acid formed after concentration reaches the required process standard while reaching the required temperature for concentrating and recycling the dilute sulfuric acid, greatly reduce the energy consumption, are efficient and practical, enhance the application range and the stability of the process, reduce the construction cost and the operation cost of a dilute sulfuric acid concentrating and recycling system, improve the economic benefit and the social benefit of dilute sulfuric acid recycling, and have wide adaptability.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A dilute sulfuric acid concentration recovery system is characterized in that: including dilute sulfuric acid preheating device, vacuum enrichment facility and concentrated sulfuric acid recovery unit, dilute sulfuric acid preheating device includes heat exchanger and first heater, vacuum enrichment facility includes the concentrated cauldron, the first entry of heat exchanger is used for being connected with dilute sulfuric acid source, the first export of heat exchanger with the entry intercommunication of first heater, the export of first heater with the entry intercommunication of concentrated cauldron, the export of concentrated cauldron with the second entry intercommunication of heat exchanger, the second export of heat exchanger with concentrated sulfuric acid recovery unit intercommunication.
2. The dilute sulfuric acid concentration recovery system according to claim 1, characterized in that: the concentrating kettle comprises a rectifying concentrating section and a heating concentrating section which are sequentially arranged along the flow direction of the dilute sulfuric acid in the concentrating kettle, wherein an inlet of the rectifying concentrating section is communicated with an outlet of the first heater, a liquid outlet of the rectifying concentrating section is communicated with an inlet of the heating concentrating section, and an outlet of the heating concentrating section is communicated with a second inlet of the heat exchanger.
3. The dilute sulfuric acid concentration recovery system according to claim 2, characterized in that: and a heating component is arranged at the bottom of the heating concentration section.
4. The dilute sulfuric acid concentration recovery system according to claim 2, characterized in that: the vacuum concentration device also comprises a condenser and a condensation tank, wherein the inlet of the condenser is communicated with the gas outlet of the rectification concentration section, and the outlet of the condenser is communicated with the inlet of the condensation tank.
5. The dilute sulfuric acid concentration recovery system according to claim 4, wherein: still include effluent treatment plant, the export of condensation tank with effluent treatment plant intercommunication, be equipped with detector and annotate alkali pipeline on the effluent treatment plant, the detector is used for detecting the pH valve of waste liquid in the effluent treatment plant, annotate alkali pipeline is used for to annotate alkali agent in the effluent treatment plant.
6. The dilute sulfuric acid concentration recovery system according to claim 5, wherein: the condensing tank is provided with a liquid ring vacuum pump, the liquid ring vacuum pump is used for enabling the vacuum concentration device to be in a negative pressure state, a liquid inlet of the liquid ring vacuum pump is connected with an outlet of the condensing tank, and a liquid outlet of the liquid ring vacuum pump is connected with the waste liquid treatment device.
7. The dilute sulfuric acid concentration recovery system according to claim 1, characterized in that: the concentrated sulfuric acid recovery device comprises a first cooler, and a second outlet of the heat exchanger is communicated with the first cooler.
8. The dilute sulfuric acid concentration recovery system according to any one of claims 1 to 7, wherein: still include dilute sulfuric acid preprocessing device, dilute sulfuric acid preprocessing device includes the dechlorination tower, the top of dechlorination tower is equipped with the feed liquor mouth that is used for letting in chlorine dilute sulfuric acid and is used for discharging the gas outlet of chlorine, and the bottom is equipped with the air inlet that is used for letting in compressed gas and the liquid outlet of discharging dilute sulfuric acid, the liquid outlet with the first entry intercommunication of heat exchanger.
9. The dilute sulfuric acid concentration recovery system of claim 8, wherein: the dilute sulfuric acid pretreatment device further comprises a circulating pump and a second heater, wherein the circulating pump is connected with a liquid outlet of the dechlorination tower and is used for pumping dilute sulfuric acid flowing out of the dechlorination tower back to the dechlorination tower, and the second heater is arranged on a pipeline which is communicated with a liquid inlet of the dechlorination tower through the circulating pump.
10. The dilute sulfuric acid concentration recovery system according to claim 9, characterized in that: the dilute sulfuric acid pretreatment device further comprises an exhaust gas treatment device, the exhaust gas treatment device comprises a second cooler and a chlorine absorption tank, an inlet of the second cooler is communicated with an air outlet of the dechlorination tower, an outlet of the second cooler is connected with the chlorine absorption tank, and dilute alkali liquor is contained in the chlorine absorption tank.
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CN111359242A (en) * | 2020-04-07 | 2020-07-03 | 苏州汉浩分离技术有限公司 | Falling film evaporator |
CN111874874A (en) * | 2020-07-28 | 2020-11-03 | 安徽东至广信农化有限公司 | Waste sulfuric acid recovery and concentration process |
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