CN1493565A - Trimeric cyanamide joint production method using one step method - Google Patents
Trimeric cyanamide joint production method using one step method Download PDFInfo
- Publication number
- CN1493565A CN1493565A CNA031592740A CN03159274A CN1493565A CN 1493565 A CN1493565 A CN 1493565A CN A031592740 A CNA031592740 A CN A031592740A CN 03159274 A CN03159274 A CN 03159274A CN 1493565 A CN1493565 A CN 1493565A
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- China
- Prior art keywords
- gas
- melamine
- ammonia
- fluidized bed
- liquid urea
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 19
- 238000000034 method Methods 0.000 title claims description 32
- XZMCDFZZKTWFGF-UHFFFAOYSA-N Cyanamide Chemical compound NC#N XZMCDFZZKTWFGF-UHFFFAOYSA-N 0.000 title 1
- 239000007789 gas Substances 0.000 claims abstract description 69
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 claims abstract description 54
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000004202 carbamide Substances 0.000 claims abstract description 26
- 239000007788 liquid Substances 0.000 claims abstract description 21
- 238000005406 washing Methods 0.000 claims abstract description 9
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 claims abstract description 7
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 claims abstract description 7
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonium chloride Substances [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 claims abstract description 7
- 235000012538 ammonium bicarbonate Nutrition 0.000 claims abstract description 7
- 239000001099 ammonium carbonate Substances 0.000 claims abstract description 7
- 235000019270 ammonium chloride Nutrition 0.000 claims abstract description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 78
- 229920000877 Melamine resin Polymers 0.000 claims description 50
- 229910021529 ammonia Inorganic materials 0.000 claims description 30
- 239000012159 carrier gas Substances 0.000 claims description 15
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 14
- 238000006243 chemical reaction Methods 0.000 claims description 9
- 239000003054 catalyst Substances 0.000 claims description 8
- 239000000843 powder Substances 0.000 claims description 8
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 7
- 239000000499 gel Substances 0.000 claims description 7
- 239000000741 silica gel Substances 0.000 claims description 7
- 229910002027 silica gel Inorganic materials 0.000 claims description 7
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 6
- 238000009835 boiling Methods 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 4
- 239000013078 crystal Substances 0.000 claims description 4
- 150000003839 salts Chemical class 0.000 claims description 4
- 239000000377 silicon dioxide Substances 0.000 claims description 4
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 3
- 235000017550 sodium carbonate Nutrition 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 2
- VQBIMXHWYSRDLF-UHFFFAOYSA-M sodium;azane;hydrogen carbonate Chemical compound [NH4+].[Na+].[O-]C([O-])=O VQBIMXHWYSRDLF-UHFFFAOYSA-M 0.000 abstract 2
- 230000003197 catalytic effect Effects 0.000 abstract 1
- 239000000047 product Substances 0.000 description 14
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 6
- 239000001569 carbon dioxide Substances 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 239000006260 foam Substances 0.000 description 2
- 239000012452 mother liquor Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- 239000006096 absorbing agent Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
A one-step process for preparing both cyanuramide and the ammonium hydrogen carbonate/sodium carbonate and ammonium chloride features that the synthetic amonia is directly delivered to the cyanuramide preparing step, where it is preheated to 350-400 deg.C and used as gas carrier of fluidized bed, and the gas from liquid urea washing tower is divdied into two channels, one returning back to crystallizer and used as cold gas and another being directly used to prepare ammonium hydrogen carbonate/sodium carbonate and ammonium chloiride. Its advantages are low cost and high catalytic efficiency.
Description
Technical Field
The invention relates to a one-step method for melamine, in particular to a one-step method for co-producing melamine.
Background
At present, melamine is generally produced from urea by high-pressure, low-pressure or normal-pressure processes. The high-pressure method and the low-pressure method have large investment, large amount of waste water and waste residue, contradictory environmental protection requirement and high total cost; the normal pressure production process has low pressure (absolute pressure of 0.10-0.15 MPa), so that the corrosion is low, the service life of equipment is long, and the main equipment can be used for at least more than 15 years. Wherein, the two-step method production process of the normal pressure method has less investment, but has higher production cost, large labor intensity and small single-set capacity; the two-step co-production process of theatmospheric method still can not get rid of the defects of low automation degree, high labor intensity, severe working environment, small single-set capacity, high consumption of raw materials and energy, poor purity of tail gas and the like of the original process; although the normal pressure one-step method gets rid of some defects of the two-step method, the method has the advantages of low labor intensity, good product quality, large single-set capacity, no waste residue and waste water discharge, larger production process investment, high power consumption and higher cost, and is basically equivalent to the two-step method.
Disclosure of Invention
The invention aims to solve the technical problems of overcoming the defects of the one-step method, the two-step method and the two-step method co-production process in the existing normal pressure method and providing the one-step method melamine co-production method with small investment ratio, low cost and small labor intensity;
the invention relates to a one-step method for co-producing melamine, wherein the structural formula of melamine is shown in the specification
It can be prepared by the following steps:
(1) directly selecting ammonia gas from a synthetic ammonia working section, preheating the ammonia gas to 150 ℃ by a carrier gas ammonia steam preheater under the pressure of 0.10-0.15 MPa and the temperature of 0-5 ℃, and heating the ammonia gas to 350-400 ℃ by a carrier gas ammonia molten salt preheater;
(2) then the liquid urea enters a fluidized bed reactor as carrier gas ammonia of the fluidized bed, under the condition that the temperature of the fluidized bed reactor is 380-400 ℃, the liquid urea branched from a liquid urea circulating pump enters the fluidized bed reactor, and melamine gas is generated through a series of reactions under the action of a catalyst, namely silica gel/silica alumina gel, and the chemical reaction formula is as follows:
(3) cooling the melamine-containing gas from the fluidized bed reactor to 310-330 ℃ by a hot gas cooler to crystallize high-boiling-point products;
(4) the gas from the hot gas cooler passes through a hot gas filter to filter high boiling point products and catalyst, namely silica gel/silica alumina gel fine powder;
(5) the filtered gas enters a crystallizer and is mixed with clean cold gas from a liquid urea washing tower, the temperature is reduced to 200-220 ℃, and melamine crystals are generated;
(6) at the moment, the low-boiling-point product is still in a gas state, and the melamine in the gas from the crystallizer is separated by a cyclone separator and is discharged from the bottom of the cyclone separator through a pressure screw;
(7) and boosting the gas exhausted by the cyclone separator by using an air cooler and then feeding the gas into a liquid urea washing tower, recovering unreacted low-boiling-point products and unseparated melamine fine powder, reducing the temperature of the gas at 200-220 ℃ to 135-145 ℃, defoaming by using a columnar cyclone separator, supplying part of the gas to a crystallizer, and feeding the other part of the gas into a co-production section.
The one-step method for co-producing melamine has a co-production section comprising synthetic ammonia, ammonium bicarbonate/synthetic ammonia, soda ash and ammonium chloride;
according tothe one-step melamine coproduction method, the carrier gas of the fluidized bed reactor is pure ammonia instead of the mixed gas of the one-step melamine method.
The one-step melamine co-production method provided by the invention integrates the large cost of the normal-pressure two-step melamine co-production method and the one-step melamine method, and has all the advantages of the two-step melamine co-production method and the one-step melamine method, so that the melamine product has good quality, low raw material consumption, small labor intensity, large scale and less investment; firstly, a main equipment compressor and related auxiliary facilities in the process are saved, the investment is saved by 40 percent compared with the normal-pressure one-step melamine method, and the power consumption is reduced by 60 percent; pure ammonia is used as carrier gas ammonia, so that the efficiency of equipment and a catalyst can be improved by 30 percent; a tail gas treatment device is not required to be newly built, the ammonia and the carbon dioxide of the by-product in the melamine reaction and the ammonia in the synthetic ammonia working section are directly absorbed by a high-level ammonia absorber together with the ammonium bicarbonate mother liquor or the alkali mother liquor, and the ammonia value of the by-product is almost equal to that of the synthetic ammonia working section; the tail gas is economically and reasonably utilized, so that the cost of the melamine is further reduced, and is 800-1000 yuan lower than that of any other process.
Drawings
The attached figure is a flow chart of a one-step method for co-producing melamine.
Detailed Description
Example 1, referring to the attached drawing, ammonia gas from an ammonia synthesis section is directly selected, the pressure is 0.10-0.15 MPa, the temperature is 0-5 ℃, 4400-4800 kg of ammonia gas is needed for producing 1 ton of melamine, the ammonia gas is preheated to 150 ℃ by a carrier gas ammonia vapor preheater, the pressure is 0.10-0.15 MPa, and then the ammonia gas is heated to 350-400 ℃ by a carrier gas ammonia molten salt preheater; then the urea enters a fluidized bed reactor as carrier gas ammonia of the fluidized bed, under the condition that the reaction temperature of the fluidized bed is 380-400 ℃, liquid urea branched from a liquid urea circulating pump enters the fluidized bed reactor, 3.05-3.15 tons of liquid urea are needed when 1 ton of melamine is produced, 60-70 g of urea can be added into each kilogram of silica gel under the action of catalyst silica gel, and melamine gas is generated through a series of reactions; cooling the melamine-containing gas from the fluidized bed to 310-330 ℃ by a hot gas cooler to crystallize high-boiling-point products; the gas from the hot gas cooler passes through a hot gas filter, and high boiling point products and catalyst silica gel fine powder are filtered out; the filtered gas enters a crystallizer and is mixed with clean cold gas from a liquid urea washing tower, the temperature is reduced to 200-220 ℃, and melamine crystals are generated; at the moment, the low-boiling-point product is still in a gas state, and the melamine in the gas from the crystallizer is spirally discharged through the bottom pressure of the cyclone separator; and boosting gas exhausted by the cyclone separator by using an air cooler and then feeding the gas into a liquid urea washing tower, wherein firstly, the unreacted low-boiling-point product and the unseparated melamine fine powder are recovered, secondly, the temperature of the gas at 200-220 ℃ is reduced to 135-145 ℃, after foam removal by the columnar cyclone separator, one partof the gas provides cold air for a crystallizer, and the other part of the gas enters an ammonium bicarbonate working section, wherein the gas purity is more than 99.5%, 0.85 ton of ammonia gas and 1.13 ton of carbon dioxide gas can be generated for each 1 ton of melamine produced, and 3.9 tons of ammonium bicarbonate or 0.85 ton of liquid ammonia can be generated.
Example 2, referring to the attached drawing, ammonia gas from an ammonia synthesis section is directly selected, the pressure is 0.10-0.15 MPa, the temperature is 0-5 ℃, 4400-4800 kg of ammonia gas is needed for producing 1 ton of melamine, the ammonia gas is preheated to 150 ℃ by a carrier gas ammonia vapor preheater, the pressure is 0.10-0.15 MPa, and then the ammonia gas is heated to 350-400 ℃ by a carrier gas ammonia molten salt preheater; then the urea enters a fluidized bed reactor as carrier gas ammonia of the fluidized bed, under the condition that the reaction temperature of the fluidized bed is 380-400 ℃, liquid urea branched from a liquid urea circulating pump enters the fluidized bed reactor, 3.05-3.15 tons of liquid urea are needed when 1 ton of melamine is produced, 60-70 grams of urea can be added into each kilogram of silica-alumina gel under the action of catalyst silica-alumina gel, and melamine gas is generated through a series of reactions; cooling the melamine-containing gas from the fluidized bed to 310-330 ℃ by a hot gas cooler to crystallize high-boiling-point products; the gas from the hot gas cooler enters a hot gas filter, and high boiling point products and catalyst silica-alumina gel fine powder are filtered out; the filtered gas enters a crystallizer and is mixed with clean cold gas from a liquid urea washing tower, the temperature is reduced to 200-220 ℃, and melamine crystals are generated; at the moment, the low-boiling-point product is still in a gas state, and the melamine in the gas from the crystallizer is spirally discharged through the bottom pressure of the cycloneseparator; and (2) boosting gas exhausted by the cyclone separator by using an air cooler and then feeding the gas into a liquid urea washing tower, wherein firstly, the unreacted low-boiling-point product and the unseparated melamine fine powder are recovered, secondly, the temperature of the gas at 200-220 ℃ is reduced to 135-145 ℃, after foam removal by the columnar cyclone separator, one part of the gas provides cold air for a crystallizer, and the other part of the gas enters an alkali-combining working section, wherein the gas purity is over 99.5 percent, 0.85 ton of ammonia gas and 1.13 ton of carbon dioxide gas can be generated for each 1 ton of melamine produced, and 2.576 tons of ammonium chloride and 2.675 tons of soda ash can be produced more or 0.85 ton of liquid ammonia can be produced more.
Claims (3)
1. A one-step method for co-producing melamine is characterized in that the method can be prepared by the following steps:
(1) directly selecting ammonia gas from a synthetic ammonia working section, preheating the ammonia gas to 150 ℃ by a carrier gas ammonia steam preheater under the pressure of 0.10-0.15 MPa and the temperature of 0-5 ℃, and heating the ammonia gas to 350-400 ℃ by a carrier gas ammonia molten salt preheater;
(2) then the liquid urea enters a fluidized bed reactor as carrier gas ammonia of the fluidized bed, under the condition that the temperature of the fluidized bed reactor is 380-400 ℃, the liquid urea branched from a liquid urea circulating pump enters the fluidized bed reactor, and melamine gas is generated through a series of reactions under the action of a catalyst, namely silica gel/silica alumina gel, and the chemical reaction formula is as follows:
(3) cooling the melamine-containing gas from the fluidized bed reactor to 310-330 ℃ by a cooler of a heater to crystallize high-boiling-point products;
(4) the gas from the cooler of the heater passes through a filter of the heater to filter high boiling point products and catalyst-silica gel/silica alumina gel fine powder;
(5) the filtered gas enters a crystallizer and is mixed with clean cold gas from a liquid urea washing tower, the temperature is reduced to 200-220 ℃, and melamine crystals are generated;
(6) at the moment, the low-boiling-point product is still in a gas state, and the melamine in the gas from the crystallizer is separated by a cyclone separator and is discharged from the bottom of the cyclone separator through a pressure screw;
(7) and boosting the gas exhausted by the cyclone separator by using an air cooler and then feeding the gas into a liquid urea washing tower, recovering unreacted low-boiling-point products and unseparated melamine fine powder, reducing the temperature of the gas at 200-220 ℃ to 135-145 ℃, defoaming by using a columnar cyclone separator, supplying part of the gas to a crystallizer, and feeding the other part of the gas into a co-production section.
2. A one-step co-production process of melamine according to claim 1, characterized in that: the co-production section can be synthetic ammonia, ammonium bicarbonate/synthetic ammonia, soda ash and ammonium chloride.
3. A one-step co-production process of melamine according to claim 1, characterized in that: the carrier gas of the fluidized bed reactor uses pure ammonia to replace the mixed gas of the one-step melamine method.
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| CN 03159274 CN1208328C (en) | 2003-09-17 | 2003-09-17 | Trimeric cyanamide joint production method using one step method |
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| CN 03159274 CN1208328C (en) | 2003-09-17 | 2003-09-17 | Trimeric cyanamide joint production method using one step method |
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Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100404421C (en) * | 2006-06-27 | 2008-07-23 | 山东联合化工股份有限公司 | Process for combined production of melamine, sodium carbonate, and ammonium chloride |
| CN101519383B (en) * | 2009-03-25 | 2010-08-25 | 北京烨晶科技有限公司 | Process for jointly producing cyanuramide, sodium carbonate and ammonium chloride by using carbamide |
| CN101113142B (en) * | 2006-07-26 | 2010-09-15 | 山东联合化工股份有限公司 | Process for combined production of melamine and ammonium nitrate |
| CN101891695A (en) * | 2010-07-27 | 2010-11-24 | 山西阳煤丰喜肥业(集团)有限责任公司 | Normal pressure one-step circulation method of melamine |
| CN101293873B (en) * | 2007-04-27 | 2011-06-29 | 丁泽华 | Optimized melamine and alkali joint production method |
| CN102276544A (en) * | 2011-05-08 | 2011-12-14 | 徐建华 | Production equipment, energy-saving production system and production method for melamine |
| CN102410518A (en) * | 2011-09-24 | 2012-04-11 | 安徽金禾实业股份有限公司 | Low-grade heat energy recycling method for liquid urea washing tower |
| CN102580711A (en) * | 2012-02-01 | 2012-07-18 | 四川金象赛瑞化工股份有限公司 | Production method for synthesizing melamine catalyst by urea with gas phase method |
| WO2012146056A1 (en) | 2011-04-28 | 2012-11-01 | 四川金象赛瑞化工股份有限公司 | Energy-saving low-cost system and process for producing melamine by means of gas quenching |
| CN102898390A (en) * | 2012-11-07 | 2013-01-30 | 马肃 | Method for heating triamine reactor carrier gas with flue gas of molten salt furnace |
| CN101610830B (en) * | 2007-02-16 | 2013-03-27 | 鲁奇有限责任公司 | Gas scrubber and use of the gas scrubber in melamine production |
| CN103102320A (en) * | 2013-01-17 | 2013-05-15 | 李鑫 | Production method of melamine by slow cooling crystallization |
| CN105903410A (en) * | 2016-06-12 | 2016-08-31 | 山东省舜天化工集团有限公司 | Method for urea melting in melamine production |
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- 2003-09-17 CN CN 03159274 patent/CN1208328C/en not_active Expired - Fee Related
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| CN100404421C (en) * | 2006-06-27 | 2008-07-23 | 山东联合化工股份有限公司 | Process for combined production of melamine, sodium carbonate, and ammonium chloride |
| CN101113142B (en) * | 2006-07-26 | 2010-09-15 | 山东联合化工股份有限公司 | Process for combined production of melamine and ammonium nitrate |
| CN101610830B (en) * | 2007-02-16 | 2013-03-27 | 鲁奇有限责任公司 | Gas scrubber and use of the gas scrubber in melamine production |
| CN101293873B (en) * | 2007-04-27 | 2011-06-29 | 丁泽华 | Optimized melamine and alkali joint production method |
| CN101519383B (en) * | 2009-03-25 | 2010-08-25 | 北京烨晶科技有限公司 | Process for jointly producing cyanuramide, sodium carbonate and ammonium chloride by using carbamide |
| CN101891695A (en) * | 2010-07-27 | 2010-11-24 | 山西阳煤丰喜肥业(集团)有限责任公司 | Normal pressure one-step circulation method of melamine |
| CN101891695B (en) * | 2010-07-27 | 2012-04-18 | 山西阳煤丰喜肥业(集团)有限责任公司 | Normal pressure one-step circulation method of melamine |
| US9114371B2 (en) | 2011-04-28 | 2015-08-25 | Beijing Edgein Technology Co., Ltd. | System and process for melamine production by gas-phase quenching method of energy efficient and cost saving type |
| KR101401136B1 (en) * | 2011-04-28 | 2014-05-29 | 시추안 골든-엘리펀트 신서리티 케미컬 컴퍼니 리미티드 | Energy-saving low-cost system and process for producing melamine by means of gas quenching |
| WO2012146056A1 (en) | 2011-04-28 | 2012-11-01 | 四川金象赛瑞化工股份有限公司 | Energy-saving low-cost system and process for producing melamine by means of gas quenching |
| JP2014512397A (en) * | 2011-04-28 | 2014-05-22 | ベイジン エッジイン テクノロジー カンパニー リミテッド | Energy saving capital saving vapor phase ching method melamine production system and method |
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| CN102580711B (en) * | 2012-02-01 | 2013-11-06 | 四川金象赛瑞化工股份有限公司 | Production method for synthesizing melamine catalyst by urea with gas phase method |
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| CN102898390A (en) * | 2012-11-07 | 2013-01-30 | 马肃 | Method for heating triamine reactor carrier gas with flue gas of molten salt furnace |
| CN103102320A (en) * | 2013-01-17 | 2013-05-15 | 李鑫 | Production method of melamine by slow cooling crystallization |
| CN105903410A (en) * | 2016-06-12 | 2016-08-31 | 山东省舜天化工集团有限公司 | Method for urea melting in melamine production |
| CN108745208A (en) * | 2018-05-04 | 2018-11-06 | 辛集市九元化工有限责任公司 | Energy-saving device and method for dissolving solid urea in melamine production |
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