CN101973948B - Method for producing melamine - Google Patents
Method for producing melamine Download PDFInfo
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- CN101973948B CN101973948B CN 201010282702 CN201010282702A CN101973948B CN 101973948 B CN101973948 B CN 101973948B CN 201010282702 CN201010282702 CN 201010282702 CN 201010282702 A CN201010282702 A CN 201010282702A CN 101973948 B CN101973948 B CN 101973948B
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- trimeric cyanamide
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Abstract
The invention discloses a method for producing melamine. Aiming to solve the problem of huge energy consumption in a tail gas circular pressurizing process in the production process of the melamine, through an optimized process design, the invention provides the method in which the production of melamine is carried out in different pressure sections and in a composite process of plural circulation and non-circulation, wherein primary tail gas is taken as carrier gas by secondary tail gas, and the secondary tail gas is not pressurized by a compressor and directly enters a reactor by utilizing over-bottom pressure of the tail gas, and thus, the compression process of the part of the gas is omitted, and the power consumption of the part of the gas is correspondingly reduced.
Description
Technical field
The invention belongs to chemical production technical field, relate in particular to a kind of production technique of trimeric cyanamide.
Background technology
The liquid phase method Melamine Production Technology that generally adopts in the world at present and domestic single stage method gas phase quenching, two step method recrystallization production technology, the building-up process of trimeric cyanamide is all finished under same pressure range (referring to that reactor inlet pressure is to the tail gas washing tower top hole pressure).The production technique of prior art is: fusing urea is pumped to reactor urea through urine and adds under entrance, the effect in atomization gas atomizing and go forward side by side in the reactor, and under the high temperature of a MPa gauge pressure and 390 ℃, through catalyst action, reaction generates trimeric cyanamide.Reacting required heat is provided by salt melting system.The fluidized-bed carrier gas hang oneself purification, cool off and the preheating of boosting after ammonia, carbon dioxide gas mixture.Reacted gaseous product, by product and carrier gas enter interchanger, hot-air filter, the solid impurities such as catalyzer in the filtering air-flow after cyclonic separator reclaims the catalyst particle that most of air-flow carries secretly.Hot-air filter is pocket type blowback structure, is provided with two, and when the strainer resistance rose to prescribed value, each continued operation with strainer to switch to another.Entered in the crystallizer by the crystallizer top from strainer dustless gas out, mix with 140 ℃ of cold process gas of coming up from the bottom.Temperature is down to 210 ℃ by 320 ℃, the trimeric cyanamide crystallization, enter together in the finished product cyclonic separator with gas mixture, the separated whirlwind bottom that gathers of trimeric cyanamide, sent separator by scraper and pressure spiral, through gas blower gas delivery, cooling, namely get the trimeric cyanamide product through fly-ash separator separation, packing.
The trimeric cyanamide dust and the urea of complete reaction not that contain trace from the gas out of finished product cyclonic separator top enter after blower fan boosts in the liquid urine washing tower, and divided three the tunnel after liquid urine washing, purifying and the cooling: the first via is after Carrier Gas Compressor boosts
Carrier gas recycles as reaction bed, and the second the tunnel returns crystallizer recycles as quenching gas, and Third Road advances exhaust treatment system.
The problem that the production technique of prior art exists is: the building-up process of trimeric cyanamide is all finished under same pressure range (referring to that reactor inlet pressure is to the tail gas washing tower top hole pressure), partial reaction tail gas after the separation of melamine is returned reactor and is done the reaction carrier gas after recycle compressor boosts, the a large amount of electric energy of pressure process consumption of circulation of tail gas, cause energy dissipation, and product cost is raise.
Summary of the invention
Purpose of the present invention is exactly the circulation of tail gas pressure process that exists for preparation technology of melamine in the prior art, consume the problem of mass energy, design by Optimization Technology, provide that a kind of production that makes trimeric cyanamide is interval at different pressures, carry out energy-saving and cost-reducing novel process under the recombination process of a plurality of circulations+do not circulate.
The objective of the invention is to be achieved through the following technical solutions: fusing urea is pumped to reactor urea through urine and adds entrance, atomizing is gone forward side by side in the reactor under the effect of atomization gas, through interchanger, hot-air filter, crystallizer, isolate the trimeric cyanamide product at the trimeric cyanamide separator, the trimeric cyanamide dust and the urea of complete reaction not that from the gas out of trimeric cyanamide separator top, contain trace, after boosting, blower fan enters in the urine washing tower, by after urine washing, purifying and the cooling minute three the tunnel: carrier gas recycled the first via as reaction bed after Carrier Gas Compressor boosts, the second the tunnel returns crystallizer recycles as quenching gas, and Third Road advances the next stage production system.
The pressure that carrier gas enters reactor is a MPa, is b MPa to the tail gas pressure that goes out behind the urine washing tower.
The pressure that preferred carrier gas enters reactor is 1.2MPa, is 1.0MPa to the tail gas pressure that goes out behind the urine washing tower.
Tail gas enters next production cycle system under b MPa pressure, enter reactor by the reactor bottom entrance after heating.Fusing urea adds entrance through being pumped to reactor urea, atomizing is gone forward side by side in the reactor under the effect of atomization gas, pass through again hot-air filter, crystallizer, the trimeric cyanamide separator, a part forms finished product, some contains trimeric cyanamide dust and the urea of complete reaction not of trace from the gas out of trimeric cyanamide separator top, after boosting, blower fan enters in the urine washing tower, by after urine washing, purifying and the cooling minute two the tunnel: the first via was returned crystallizer and is recycled as quenching gas, and the second the tunnel advances next stage production cycle system or exhaust treatment system.
The pressure that carrier gas enters reactor is approximately b MPa, is c MPa to the tail gas pressure that goes out behind the urine washing tower.
The pressure that preferred carrier gas enters reactor is approximately 1.0MPa, is 0.8MPa to the tail gas pressure that goes out behind the urine washing tower.The gaseous tension that namely advances next stage production system or exhaust treatment system is c MPa, by that analogy.
Tail gas behind the second stage is done carrier gas, without compressor pressurizes, directly utilizes the tail gas overbottom pressure to enter the next stage reactor,
According to the size of height and every grade of pressure reduction of first step pressure, the production process of multistage trimeric cyanamide can be set as mentioned above.
Beneficial effect of the present invention: the tail gas behind the second stage is done carrier gas, without compressor pressurizes, directly utilize the tail gas overbottom pressure to enter reactor, then saved the compression process of this portion gas, saved accordingly the power consumption of this portion gas compression.
Description of drawings
Describe embodiments of the invention in detail below in conjunction with accompanying drawing
Fig. 1 is the preparation technology of melamine schema of prior art
Fig. 2 is preparation technology of melamine schema of the present invention
Embodiment
Fusing urea is pumped to reactor urea through urine and adds under population, the effect in atomization gas atomizing and go forward side by side in the reactor, and under the high temperature of 1.2MPa gauge pressure and 390 ℃, through catalyst action, reaction generates trimeric cyanamide.Reacting required heat is provided by salt melting system.The fluidized-bed carrier gas hang oneself purification, cool off and the preheating of boosting after ammonia, carbon dioxide gas mixture.Reacted gaseous product, by product and carrier gas enter interchanger, hot-air filter, the solid impurities such as catalyzer in the filtering air-flow after cyclonic separator reclaims the catalyst particle that most of air-flow carries secretly.Hot-air filter is pocket type blowback structure, is provided with two, when the strainer resistance rises to prescribed value, switches to another reserve filter and continues operation.Entered in the crystallizer by the crystallizer top from strainer dustless gas out, mix with 140 ℃ of cold process gas of coming up from the bottom.Temperature is down to 210 ℃ by 320 ℃, the trimeric cyanamide crystallization, enter together in the finished product cyclonic separator with gas mixture, the separated whirlwind bottom that gathers of trimeric cyanamide, sent separator by scraper and pressure spiral, through gas blower gas delivery, cooling, namely get the trimeric cyanamide product through fly-ash separator separation, packing.
The trimeric cyanamide dust and the urea of complete reaction not that from the gas out of finished product cyclonic separator top, contain trace, after boosting, blower fan enters in the liquid urine washing tower, by after liquid urine washing, purifying and the cooling minute three the tunnel: carrier gas recycled the first via as reaction bed after Carrier Gas Compressor boosts, the second the tunnel returns crystallizer recycles as quenching gas, and Third Road tail gas advances the next stage production system.
The pressure that carrier gas enters reactor is 1.2MPa, is 1.0MPa to the tail gas pressure that goes out behind the urine washing tower.
Tail gas directly enters next production system under 1.0MPa pressure, enter reactor by the reactor bottom entrance after heating.Fusing urea adds under population, the effect in atomization gas atomizing and goes forward side by side in the reactor through being pumped to reactor urea, and under the high temperature of approximate 1.0MPa gauge pressure and 390 ℃, through catalyst action, reaction generates trimeric cyanamide.Reacting required heat is provided by salt melting system.The fluidized-bed carrier gas hang oneself purification, cool off and the preheating of boosting after ammonia, carbon dioxide gas mixture.Reacted gaseous product, by product and carrier gas enter interchanger, hot-air filter, the solid impurities such as catalyzer in the filtering air-flow after cyclonic separator reclaims the catalyst particle that most of air-flow carries secretly.Hot-air filter is pocket type blowback structure, is provided with two, when the strainer resistance rises to prescribed value, switches to another reserve filter and continues operation.Entered in the crystallizer by the crystallizer top from strainer dustless gas out, mix with 140 ℃ of cold process gas of coming up from the bottom.Temperature is down to 210 ℃ by 320 ℃, the trimeric cyanamide crystallization, enter together in the finished product cyclonic separator with gas mixture, the separated whirlwind bottom that gathers of trimeric cyanamide, sent separator by scraper and pressure spiral, through gas blower gas delivery, cooling, namely get the trimeric cyanamide product through fly-ash separator separation, packing.
The trimeric cyanamide that from the gas out of finished product cyclonic separator top, contains trace.
Claims (1)
1. method for producing melamine, it is characterized in that fusing urea is pumped to reactor urea through urine and adds entrance, atomizing is gone forward side by side in the reactor under the effect of atomization gas, the pressure that carrier gas enters reactor is 1.2MPa, through interchanger, hot-air filter, enter the trimeric cyanamide separator behind the crystallizer, the trimeric cyanamide dust and the urea of complete reaction not that from the gas out of trimeric cyanamide separator top, contain trace, after boosting, blower fan enters in the urine washing tower, being urinated washing, purifying and cool off rear tail gas pressure by liquid is 1.0MPa, and divides three the tunnel: carrier gas recycles the first via as reaction bed after Carrier Gas Compressor boosts; The second the tunnel returns crystallizer recycles as quenching gas; Third Road tail gas need not be through the Carrier Gas Compressor pressurization, directly under 1.0MPa pressure, enter the next stage production system, after heating, enter reactor by next stage reactor bottom entrance, fusing urea adds entrance through being pumped to reactor urea, atomizing is gone forward side by side in the reactor under the effect of atomization gas, pass through again interchanger, hot-air filter, crystallizer, isolate the trimeric cyanamide finished product at the trimeric cyanamide separator, the trimeric cyanamide dust and the urea of complete reaction not that from the gas out of trimeric cyanamide separator top, contain trace, after boosting, blower fan enters in the urine washing tower, after urine washing, purifying and cooling, tail gas pressure is 0.8MPa, and divide two the tunnel: the first via is returned crystallizer and is recycled as quenching gas, the second the tunnel enters next stage production cycle system or exhaust treatment system, namely the tail gas behind the second stage is done carrier gas, without compressor pressurizes, directly utilize the tail gas overbottom pressure to enter the next stage reactor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010282702 CN101973948B (en) | 2010-09-11 | 2010-09-11 | Method for producing melamine |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201010282702 CN101973948B (en) | 2010-09-11 | 2010-09-11 | Method for producing melamine |
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| CN101973948A CN101973948A (en) | 2011-02-16 |
| CN101973948B true CN101973948B (en) | 2013-03-27 |
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| CN 201010282702 Expired - Fee Related CN101973948B (en) | 2010-09-11 | 2010-09-11 | Method for producing melamine |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102489095A (en) * | 2011-10-27 | 2012-06-13 | 山东省舜天化工集团有限公司 | Method for purifying melamine tail gas |
| CN102558079B (en) * | 2011-12-30 | 2014-06-25 | 南通紫鑫实业有限公司 | Process for producing melamine |
| CN102584730B (en) * | 2012-03-12 | 2014-08-27 | 李靖铭 | Equipment and process for producing melamine under low pressure |
| CN104292173A (en) * | 2014-09-08 | 2015-01-21 | 山东省舜天化工集团有限公司 | Melamine crystallizer-based gas heat recovery method |
| CN111983136A (en) * | 2020-07-30 | 2020-11-24 | 青岛惠城环保科技股份有限公司 | Melamine catalyst performance evaluation equipment |
| CN115073389B (en) * | 2022-07-01 | 2023-10-31 | 山东省舜天化工集团有限公司 | Energy-saving melamine production system and production method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1188761A (en) * | 1998-02-24 | 1998-07-29 | 蒋大洲 | Preparation technology of melamine and its device |
| CN1657526A (en) * | 2004-02-17 | 2005-08-24 | 山东海化魁星化工有限公司 | Process for preparing melamine |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009080176A2 (en) * | 2007-12-20 | 2009-07-02 | Dsm Ip Assets B.V. | Process for the preparation of melamine |
| EP2119710A1 (en) * | 2008-05-14 | 2009-11-18 | Urea Casale S.A. | Process for producing high-quality melamine from urea |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1188761A (en) * | 1998-02-24 | 1998-07-29 | 蒋大洲 | Preparation technology of melamine and its device |
| CN1657526A (en) * | 2004-02-17 | 2005-08-24 | 山东海化魁星化工有限公司 | Process for preparing melamine |
Non-Patent Citations (2)
| Title |
|---|
| 常压法三聚氰胺生产工艺;郭慧 等;《辽宁化工》;20080531;第37卷(第5期);330-331 * |
| 郭慧 等.常压法三聚氰胺生产工艺.《辽宁化工》.2008,第37卷(第5期),330-331. |
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| CN101973948A (en) | 2011-02-16 |
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