CN219849533U - Melamine's apparatus for producing - Google Patents
Melamine's apparatus for producing Download PDFInfo
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- CN219849533U CN219849533U CN202320526407.2U CN202320526407U CN219849533U CN 219849533 U CN219849533 U CN 219849533U CN 202320526407 U CN202320526407 U CN 202320526407U CN 219849533 U CN219849533 U CN 219849533U
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- melamine
- washing tower
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- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 title claims abstract description 57
- 229920000877 Melamine resin Polymers 0.000 title claims abstract description 55
- 239000007787 solid Substances 0.000 claims abstract description 49
- 238000004519 manufacturing process Methods 0.000 claims abstract description 43
- 239000007788 liquid Substances 0.000 claims abstract description 42
- 238000005406 washing Methods 0.000 claims abstract description 29
- 238000000034 method Methods 0.000 claims description 36
- 230000008569 process Effects 0.000 claims description 30
- 238000010791 quenching Methods 0.000 claims description 20
- 230000000171 quenching effect Effects 0.000 claims description 20
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 19
- 239000004202 carbamide Substances 0.000 claims description 19
- 238000000926 separation method Methods 0.000 claims description 16
- 238000001816 cooling Methods 0.000 claims description 13
- 239000000047 product Substances 0.000 claims description 13
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 12
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 9
- 239000006227 byproduct Substances 0.000 claims description 8
- 239000003054 catalyst Substances 0.000 claims description 7
- 238000001914 filtration Methods 0.000 claims description 7
- 239000001569 carbon dioxide Substances 0.000 claims description 6
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 6
- 238000006555 catalytic reaction Methods 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 4
- 238000005243 fluidization Methods 0.000 claims description 3
- 238000003860 storage Methods 0.000 claims description 3
- 230000003139 buffering effect Effects 0.000 claims description 2
- 230000000087 stabilizing effect Effects 0.000 claims description 2
- 238000005265 energy consumption Methods 0.000 abstract description 5
- 239000000126 substance Substances 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 131
- 210000002700 urine Anatomy 0.000 description 13
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 6
- 239000010779 crude oil Substances 0.000 description 6
- 239000003921 oil Substances 0.000 description 5
- 239000012159 carrier gas Substances 0.000 description 4
- 238000002425 crystallisation Methods 0.000 description 4
- 230000008025 crystallization Effects 0.000 description 4
- 150000003839 salts Chemical class 0.000 description 4
- 238000001994 activation Methods 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- YZEZMSPGIPTEBA-UHFFFAOYSA-N 2-n-(4,6-diamino-1,3,5-triazin-2-yl)-1,3,5-triazine-2,4,6-triamine Chemical compound NC1=NC(N)=NC(NC=2N=C(N)N=C(N)N=2)=N1 YZEZMSPGIPTEBA-UHFFFAOYSA-N 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- YSRVJVDFHZYRPA-UHFFFAOYSA-N melem Chemical compound NC1=NC(N23)=NC(N)=NC2=NC(N)=NC3=N1 YSRVJVDFHZYRPA-UHFFFAOYSA-N 0.000 description 2
- 239000003595 mist Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- ROBVLQBZPQQRTQ-UHFFFAOYSA-N [N].C1=CN=NN=C1 Chemical compound [N].C1=CN=NN=C1 ROBVLQBZPQQRTQ-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- BVCZEBOGSOYJJT-UHFFFAOYSA-N ammonium carbamate Chemical compound [NH4+].NC([O-])=O BVCZEBOGSOYJJT-UHFFFAOYSA-N 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- KXDHJXZQYSOELW-UHFFFAOYSA-N carbonic acid monoamide Natural products NC(O)=O KXDHJXZQYSOELW-UHFFFAOYSA-N 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- -1 heterocyclic organic compound Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000008247 solid mixture Substances 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The utility model belongs to the technical field of organic chemical industry, and relates to a melamine production device. The production device comprises a gas washing tower, a reactor, a cooler, a filter, a quencher, a gas-solid separator, a booster, a gas-liquid separator, a circulating gas fan, a cyclone demister or redistributor, a steam heater, a finished product bin, a tail gas treatment system and connecting pipelines. The melamine production device provided by the utility model can be used for producing melamine with long operation period, low energy consumption, stable quality and high economical efficiency.
Description
Technical Field
The utility model belongs to the technical field of organic chemical industry, and relates to a melamine production device.
Background
Melamine (Melamine), commonly known as Melamine, protein essence, is chemically named 1,3, 5-triazine-2, 4, 6-triamine, and has a molecular formula of C 3 N 6 H 6 Is a triazine nitrogen-containing heterocyclic organic compound, and is widely used as a chemical raw material.
At present, melamine is mainly produced by taking urea as a raw material, and the reaction production principle is as follows:
6(NH 2 ) 2 CO＝C 3 N 6 H 6 +3CO 2 +6NH 3
the production method is divided into a high-pressure method and a low-pressure method, wherein most of domestic enterprises use the low-pressure method, and most of the production methods adopt gas-phase quenching in the process, and specific process devices and process flows are shown in figure 1.
Liquid urine at about 140 ℃ from the urea production process enters the liquid urine washing tower 101, is pressurized by a liquid urine pump, and circulates through the liquid urine washing tower 101. And then a part of liquid urine and atomized ammonia enter a fluidized bed reactor 102 which is heated to 400 ℃ by molten salt, the liquid urine reacts in the fluidized bed reactor 102 to generate gaseous melamine, ammonia and carbon dioxide high-temperature mixed gas, and the heat required by the reaction is provided by a molten salt furnace system. The reacted gas enters a hot gas cooler 103 to exchange heat with crude oil, the crude oil takes heat away to generate steam, the cooled mixed gas enters a hot gas filter 104 to be filtered, the filtered process gas containing melamine gas enters a crystallizer 105 to be mixed with cold gas sent by a cold gas fan and washed and cooled by a liquid urine washing tower 101, the melamine is separated out by crystallization, and the melamine enters a catcher 106 along with the mixed gas to be subjected to gas-solid separation, and the melamine is obtained after separation and is collected in a finished product bin 107. The gas exits the top of the trap 106 into the liquid urine scrubber 101. Part of the process gas of the liquid urine washing tower 101 enters the fluidized bed reactor 102 after passing through the carrier gas compressor 110 and the carrier gas heater 111; part of the process gas is sent into the crystallizer 105 after being subjected to gas-liquid separation by a cold air demister 108 and then is boosted by a cold air fan 109; part of the process gas enters the tail gas treatment system before the cold air blower 109.
The production method has the following defects:
1. the device has a short operation period, generally about 3 months, and cannot operate for a long period, so that the yield, quality, energy consumption and the like cannot be improved;
2. the operation of the hot gas cooler is unstable, and the control of the oil production system is unstable, so that the scaling and blockage inside the row pipe of the hot gas cooler are easily caused;
3. the cooled gas is pressurized by a carrier gas compressor and then is sent into a carrier gas preheater for heating, so that the fuel consumption is increased;
4. the hot gas cooler and the hot gas filter are combined one by one, so that the maximum use efficiency of the equipment is seriously reduced;
5. the pressurized process gas of the cold air blower directly enters the crystallizer, and the product quality is seriously affected.
Disclosure of Invention
The utility model aims to provide a melamine production device which can produce melamine with long operation period, low energy consumption, stable quality and high economy.
To achieve this object, in a basic embodiment, the utility model provides a melamine production plant comprising a gas scrubber, a reactor, a cooler, a filter, a quencher, a gas-solid separator, a booster, a gas-liquid separator, a circulating gas blower, a cyclone mist eliminator or redistributor, a steam heater, a finishing bin, a tail gas treatment system, and connecting lines,
introducing molten urea into the gas washing tower;
the reactor is used for enabling the molten urea from the gas washing tower to react under the catalysis of a catalyst to generate mixed gas of melamine gas, ammonia gas, carbon dioxide and a small amount of byproducts;
the cooler and the filter are respectively used for cooling and filtering the mixed gas;
the quenching device is used for quenching the cooled and filtered mixed gas so as to crystallize and separate melamine, and the melamine enters the gas-solid separator along with the mixed gas for gas-solid separation;
the finished product bin is used for collecting solids obtained by gas-solid separation;
the gas obtained by gas-solid separation is divided into two paths, one path is heated by the steam heater and is pressurized by the booster and then enters the reactor to be used as fluidizing gas, and the other path is sent into the gas washing tower, and after being washed by the molten urea, the gas washing tower is subjected to heat exchange and cooling;
the gas-liquid separator is used for separating and removing liquid from the gas discharged from the gas washing tower after heat exchange and cooling;
and one part of the gas after liquid removal is pressurized by the circulating gas fan, the cyclone demister or the redistributor is further demisted and then enters the quenching device to be used as quenching process gas, and the other part of the gas enters the tail gas treatment system to be subjected to tail gas treatment.
In a preferred embodiment, the utility model provides a melamine production plant, wherein in the cooler, the mixed gas in the cooler pipe exchanges heat with the green liquor circulating outside the cooler pipe.
In a preferred embodiment, the utility model provides a melamine production plant, wherein the production plant further comprises a hot runner green tank for storing the runner green liquor after heat exchange with the mixed gas.
In a preferred embodiment, the utility model provides a melamine production plant wherein said cooler and said filter are provided in series and/or in parallel groups, respectively.
In a preferred embodiment, the utility model provides a melamine production plant, wherein the plant further comprises a distributor arranged between the cooler and the filter for distributing different coolers for use in connection with different filters.
In a preferred embodiment, the present utility model provides a melamine production plant, wherein the gas-solid separator is divided into a primary gas-solid separator and a secondary gas-solid separator connected to each other.
In a preferred embodiment, the utility model provides a melamine production plant, wherein said production plant further comprises a fine filter and/or a heater,
the fine filter is arranged on a pipeline connecting the steam heater and the supercharger and is used for further filtering gas;
the heater is arranged on a pipeline connecting the supercharger and the reactor and is used for further heating gas.
In a preferred embodiment, the present utility model provides a melamine production plant in which the gas-liquid separator is divided into a primary gas-liquid separator and a secondary gas-liquid separator connected to each other.
In a preferred embodiment, the utility model provides a melamine production plant, wherein said plant further comprises an intake buffer tank for buffering cooled gas before entering said circulating gas fan, stabilizing the supply of gas to said circulating gas fan.
The melamine production device has the beneficial effects that the melamine production device can be used for producing melamine with long operation period, low energy consumption, stable quality and high economy.
The beneficial effects of the utility model are as follows:
(1) The channel system is added with a hot channel storage tank, and the cooler activation process is optimized, so that the effect is obvious, and the running period of the device can reach more than 6 months.
(2) Part of gas of the secondary gas-solid separator passes through a steam heater and a fine filter, enters a booster to be pressurized, and then enters the heater, so that the temperature is increased by about 60 ℃, and the amount of melamine per ton of coal is reduced by 3 Kg.
(3) The cooler and the filter are matched with each other in a random combination mode, so that the service efficiency of the equipment is effectively improved, and the energy consumption is reduced.
(4) The air buffer tank is added at the inlet of the circulating air fan, so that the air supply of the circulating air fan is stabilized, the running of a unit is stabilized, and the risk of vehicle jump caused by fluctuation of a vibration value due to unstable air intake is thoroughly eliminated; the cyclone demister or redistributor is added at the outlet of the circulating gas fan to further clean the process gas and ensure the stability of the product quality.
(5) The air inlet mode of the quenching device is further optimized, and the uniformity of the air quantity of each branch is ensured.
(6) A steam heater is added between the secondary gas-solid separator and the fine filter.
Drawings
Fig. 1 is a process unit and a process flow chart for preparing melamine by a low-pressure method, which are used by most enterprises in China.
Fig. 2 is a constitution diagram of an exemplary melamine production apparatus of the present utility model.
Detailed Description
The composition structure of the melamine production apparatus of the present utility model is shown in fig. 2, and includes a gas scrubber 1, a reactor 2, a cooler 3, a distributor 4, a filter 5, a quencher 6, a primary gas-solid separator 7, a secondary gas-solid separator 8, a fine filter 9, a supercharger 10, a heater 11, a primary gas-liquid separator 12, a secondary gas-liquid separator 13, an intake buffer tank 14, a circulating gas blower 15, a cyclone mist eliminator or redistributor 16, a steam heater 17, a hot-runner raw tank 18, a finished product bin 19, an exhaust gas treatment system, and respective connecting pipes.
The gas scrubber 1 is fed with molten urea.
The reactor 2 is used for reacting the molten urea from the gas scrubber 1 under the catalysis of a catalyst to produce a mixture of melamine gas, ammonia gas, carbon dioxide and a small amount of by-products.
The cooler 3 and the filter 5 are respectively used for cooling and filtering the mixed gas, and are all in parallel connection. The distributor 4 is arranged between the coolers 3 and the filters 5 and is used for distributing different coolers 3 to be connected with different filters 5 for matching use. In the cooler 3, the mixed gas in the pipe of the cooler 3 exchanges heat with the green liquor circulating outside the pipe of the cooler 3. The hot runner system tank 18 is used for storing the runner system liquid after heat exchange with the mixed gas, and is used when the cooler 3 is activated.
The quencher 6 is used for quenching the cooled and filtered mixed gas, so that melamine is crystallized and separated out, and the melamine enters the first-stage gas-solid separator 7 and the second-stage gas-solid separator 8 which are connected in sequence along with the mixed gas for gas-solid separation.
The finished product bin 19 is used for collecting solids obtained by gas-solid separation.
The gas obtained by gas-solid separation is divided into two paths, one path is heated by a steam heater 17, a fine filter 9 (one or more than one path are all provided with back blowing devices) is further filtered, a booster 10 is boosted (a connecting pipeline between the fine filter 9 and the booster 10 is a nitrogen jacket pipe), and after being further heated by a heater 11, the gas enters a reactor 2 through 6 gas inlet of a bottom part to be used as fluidizing gas; the other path is sent into the gas washing tower 1 and is subjected to heat exchange and cooling in the gas washing tower 1 after being washed by the molten urea.
The first-stage gas-liquid separator 12 and the second-stage gas-liquid separator 13 which are connected in sequence are used for separating and removing liquid from the gas of the gas washing tower 1 after heat exchange and cooling.
Part of the gas after liquid removal is buffered by an air inlet buffer tank 14, pressurized by a circulating air fan 15, further defogged by a cyclone defogger or redistributor 16 and then enters a quencher 6 to be used as quenching process gas, and the other part enters a tail gas treatment system to be treated.
An exemplary melamine production method using the above-described exemplary melamine production apparatus of the present utility model comprises the steps of:
(1) The melted urea enters a gas washing tower 1 for circulation, then part of the melted urea enters a reactor 2 for reaction under the catalysis of a catalyst to generate mixed gas of melamine gas, ammonia gas, carbon dioxide and a small amount of byproducts,
(2) The mixed gas enters the cooler 3 and the filter 5 in sequence for cooling and filtering, then enters the quencher 6 for quenching, thereby crystallizing and separating melamine, enters the first-stage gas-solid separator 7 and the second-stage gas-solid separator 8 together with the mixed gas for gas-solid separation,
(3) The separated solids enter a finished product bin 19 to be collected, the separated gas is divided into two paths, one path is heated by a steam heater 17, the fine filter 9 is further filtered, the booster 10 is used for boosting, and the heated gas enters a reactor 2 to be used as fluidization gas after being further heated by a heater 11; the other path is sent into a gas washing tower 1, after being washed by the melted urea, the other path is subjected to heat exchange and cooling in the gas washing tower 1,
(4) The cooled gas is discharged from the gas washing tower 1, liquid is removed through the primary gas-liquid separator 12 and the secondary gas-liquid separator 13, part of the cooled gas is buffered through the gas inlet buffer tank 14, the circulating gas fan 15 is pressurized, the cyclone demister or the redistributor 16 is further demisted and then enters the quenching device 6 to be used as quenching process gas, and the other part of the cooled gas enters the tail gas treatment system to be subjected to tail gas treatment.
The operation of the above-described exemplary melamine production process is exemplified as follows:
99.5% (wt) of the molten urine from the urea plant is fed to the gas scrubber 1 after being pressurized by a molten urea pump in the urea plant.
The reaction process gas from the booster 10 is heated to 395-405 ℃ by molten salt of a heater tube side, and then enters the reactor 2, wherein the bottom temperature of the reactor is 395-405 ℃, the middle temperature is 395-405 ℃, the upper temperature is 395-405 ℃, the operating pressure is 0.7-1.2MPa (G), and liquid urine at 135-140 ℃ from a liquid urine pump enters the reactor 2 along with atomized gas.
The atomized urea reacts under the action of a silica-alumina gel catalyst at the high temperature of 0.7-1.2MPa (G) and 390+/-5 ℃ to generate mixed gas of melamine gas, ammonia gas, carbon dioxide and a small amount of byproducts (melam and melem, the volume content of which is 0.1-0.5 percent), and the heat required by the reaction is provided by a molten salt system.
The gas products and byproducts after the urea reaction enter a pipe of a cooler 3 and exchange heat with the green liquor outside the pipe in a circulating way, the temperature is reduced from 380 ℃ to 390 ℃ to 350 ℃ to 370 ℃, and the high-boiling byproducts, such as melem, melam and the like, are crystallized and separated out. The heat released by the reaction gas is carried by the green liquor to the green condenser to generate saturated steam of 2.5MPa (G), and the gas phase pressure of the green system is 0.2-0.5MPa (G).
The gas-solid mixture (350-370 ℃) from the cooler 3 passes through the distributor 4 and then enters the filter 5 to filter out solid impurities such as catalyst and high-boiling byproducts in the gas flow. The filter 5 is used in combination with the cooler 3 at random via the distributor 4.
Clean gas (330-360 ℃) from the filter 5 enters the quenching device 6 from the top of the quenching device 6, is mixed with cold process gas at 140-160 ℃ from the bottom, the gas temperature is reduced from 330-360 ℃ to 195-220 ℃, melamine is crystallized and separated out, the melamine enters the primary gas-solid separator 7 together with the mixed gas, the melamine solid phase is separated and gathered to the bottom of the primary gas-solid separator 7, and is sent out of the primary gas-solid separator 7 by a scraper, and is sent to a packaging procedure for cooling and packaging by a pneumatic conveying device, thus obtaining the melamine product. The gas coming out from the top of the primary gas-solid separator 7 contains a small amount of melamine solid dust, and enters the secondary gas-solid separator 8 for gas-solid separation.
The process gas exiting the secondary gas-solid separator 8 is split into two paths, and one path of process gas enters the fine filter 9 after being heated by the steam heater 17. The process gas after fine filtration (195-220 ℃) enters a booster 10, and the process gas after being boosted to 0.7-1.2MPa (G) is used as fluidization gas of a reactor 2. The other path of 80-85% process gas is sent into the gas washing tower 1, and is cooled to 135-145 ℃ through the washing of urine in the gas washing tower 1 and the heat exchange of a high-efficiency tube bundle heat exchanger. The gas washing tower 1 is internally provided with 3-6 sections of high-efficiency tube bundle heat exchangers, the heat exchangers are assembled and welded with the gas washing tower 1, deoxygenated water enters the lower part of the tube bundles of the heat exchangers, the deoxygenated water absorbs heat in the tubes and then is separated into gas and liquid in space on the tube bundles, steam is output at the upper part, liquid returns to the lower part, generated steam with the pressure of 0.1-0.3MPa (G) is sent into an air cooler or a waste heat utilization device through a pipeline for cooling, and cooled condensate flows back into the heat exchange tube bundles for recycling.
The process gas at 135-145 ℃ of the gas scrubber 1 is divided into two paths: the first path enters an air inlet buffer tank 14, is pressurized to 0.5-1.0MPa (G) by a circulating air fan 15, enters a cyclone demister or redistributor 16, and enters a quenching device 6 to be used as quenching process gas after further demisting; the second path enters the tail gas treatment system (accounting for 3% -5% of the total gas).
For the above exemplary apparatus, methods, and operations, it should be noted that:
(1) The raw oil system of the cooler 3 is the second heat transfer point of the apparatus of the present utility model, and the hot gas from the reactor 2 exchanges heat with the raw oil through the cooler 3, and the heat is brought to the raw oil condenser by the raw oil to generate 2.5MPa (G) steam. Due to the existence of the crude oil, crystals and catalyst powder are attached to the inner wall of the tube array of the cooler 3, and in order to ensure that the tube array of the cooler 3 is activated cleanly, a hot-channel crude oil storage tank is added in the process, so that the crude oil can be removed no matter which cooler 3 is activated, the better activation effect of the cooler 3 is ensured, and the hot-channel crude oil is conveyed into the cooler 3 by nitrogen after the activation is finished, so that the operation period of the cooler 3 is ensured to be more than 6 months.
(2) The process gas exiting the secondary gas-solid separator 8 also contains solid melamine particles which cannot be trapped, and if the gas directly enters the supercharger 10, the gas can cause wall formation in an inlet pipeline of the supercharger 10 and wall formation and blockage of an inlet flow passage of the supercharger 10.
(3) At present, the domestic technology basically forms a one-to-one combined kit of the cooler 3 and the filter 5, and one of the cooler 3 or the filter 5 is out of operation when the other cooler or the filter 5 is out of operation. The process of the utility model is added with the distributor 4, which can lead the cooler 3 and the filter 5 to be matched and combined at will, any cooler 3 or filter 5 can be isolated from the system independently for on-line treatment, and the efficiency of each device is maximized.
(4) The inlet of the circulating air blower 15 of most of the processes in China is directly connected with a pipeline, and liquid drops in the gas can greatly influence the running condition of a unit. The inlet of the circulating air fan 15 is additionally provided with the air inlet buffer tank 14, so that the air supply of the circulating air fan 15 is stabilized, the running of a unit is stabilized, and the risk of vehicle jump caused by fluctuation of a vibration value due to unstable air inlet is thoroughly eliminated. The cyclone demister or redistributor 16 is added at the outlet of the circulating air fan 15 to further clean the process air, so that the stability of the product quality is ensured, and the quality rate of the product reaches more than 98%.
(5) The inlet of the process gas from the cyclone demister or redistributor 16 of the quencher 6 is in a sectional gas supply mode, the inlet main pipe is divided into two paths, each path is divided into two small paths, and an equal number of outlet branch pipes are led out of each small path to enter the quencher 6. The air inlet mode is more optimized, the air quantity of each branch pipe is ensured to be uniform, the quenching is complete and thorough, the problem of crystallization backward movement caused by incomplete quenching process is avoided, and the crystallization backward movement is one of the main reasons of blocking the crystallization wall at present.
(6) A steam heater 17 is added between the secondary gas-solid separator 8 and the fine filter 9, the temperature is increased by 10-20 ℃, and the generation of ammonium carbamate is reduced. The pipeline between the fine filter 9 and the supercharger 10 is heated by a nitrogen jacket, so that the temperature rise at 10-20 ℃ is not reduced, the risk of blockage caused by wall junction of the inner wall of the pipeline is greatly reduced, and the running period of the supercharger 10 is prolonged.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present utility model without departing from the spirit or scope of the utility model. Thus, it is intended that the present utility model also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof. The foregoing examples or embodiments are merely illustrative of the utility model, which may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The described embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. The scope of the utility model should be indicated by the appended claims, and any changes that are equivalent to the intent and scope of the claims are intended to be encompassed within the scope of the utility model.
Claims (9)
1. A melamine production device, which is characterized in that: the production device comprises a gas washing tower, a reactor, a cooler, a filter, a quencher, a gas-solid separator, a booster, a gas-liquid separator, a circulating gas fan, a cyclone demister or redistributor, a steam heater, a finished product bin, a tail gas treatment system and connecting pipelines,
introducing molten urea into the gas washing tower;
the reactor is used for enabling the molten urea from the gas washing tower to react under the catalysis of a catalyst to generate mixed gas of melamine gas, ammonia gas, carbon dioxide and a small amount of byproducts;
the cooler and the filter are respectively used for cooling and filtering the mixed gas;
the quenching device is used for quenching the cooled and filtered mixed gas so as to crystallize and separate melamine, and the melamine enters the gas-solid separator along with the mixed gas for gas-solid separation;
the finished product bin is used for collecting solids obtained by gas-solid separation;
the steam heater and the booster are used for heating and boosting one path of gas obtained by gas-solid separation in sequence and then sending the heated and pressurized gas into the reactor to serve as fluidization gas;
the gas-solid separator is also connected with the gas washing tower so as to send the other path of the gas obtained by gas-solid separation into the gas washing tower, and after the other path of the gas obtained by gas-solid separation is washed by the molten urea, the gas washing tower is subjected to heat exchange and cooling;
the gas-liquid separator is used for separating and removing liquid in the gas which flows out of the gas washing tower after heat exchange and cooling;
the cyclone demister or the redistributor is used for pressurizing and demisting a part of gas separated from liquid in sequence and then sending the gas into the quencher as quenching process gas;
the tail gas treatment system is used for carrying out tail gas treatment on the other part of the gas after the liquid is separated and removed.
2. The production device according to claim 1, wherein: in the cooler, the mixed gas in the cooler pipe exchanges heat with the channel green liquor circulating outside the cooler pipe.
3. The production device according to claim 2, characterized in that: the production device also comprises a hot runner green storage tank for storing the runner green liquid after heat exchange with the mixed gas.
4. The production device according to claim 1, wherein: the cooler and the filter are respectively provided with a plurality of groups connected in series and/or in parallel.
5. The production device according to claim 4, wherein: the production device also comprises a distributor which is arranged between the cooler and the filter and is used for distributing different coolers to be matched with different filters after being connected.
6. The production device according to claim 1, wherein: the gas-solid separator is divided into a primary gas-solid separator and a secondary gas-solid separator which are connected with each other.
7. The production device according to claim 1, wherein: the production device also comprises a fine filter and/or a heater,
the fine filter is arranged on a pipeline connecting the steam heater and the supercharger and is used for further filtering gas;
the heater is arranged on a pipeline connecting the supercharger and the reactor and is used for further heating gas.
8. The production device according to claim 1, wherein: the gas-liquid separator is divided into a primary gas-liquid separator and a secondary gas-liquid separator which are connected with each other.
9. The production device according to claim 1, wherein: the production device also comprises an air inlet buffer tank which is used for buffering the cooled air before entering the circulating air fan and stabilizing the air supply of the circulating air fan.
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