CN102584731A - Process for coproducing melamine and ammonium sulfate - Google Patents

Process for coproducing melamine and ammonium sulfate Download PDF

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Publication number
CN102584731A
CN102584731A CN2011104526385A CN201110452638A CN102584731A CN 102584731 A CN102584731 A CN 102584731A CN 2011104526385 A CN2011104526385 A CN 2011104526385A CN 201110452638 A CN201110452638 A CN 201110452638A CN 102584731 A CN102584731 A CN 102584731A
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China
Prior art keywords
ammonium sulfate
gas
melamine
tail gas
urea
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Pending
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CN2011104526385A
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Chinese (zh)
Inventor
沈铁清
朱国清
姚尧
杨斌峰
马立新
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NANTONG ZIXIN INDUSTRIAL CO LTD
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NANTONG ZIXIN INDUSTRIAL CO LTD
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Priority to CN2011104526385A priority Critical patent/CN102584731A/en
Publication of CN102584731A publication Critical patent/CN102584731A/en
Pending legal-status Critical Current

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Abstract

The invention relates to a process for coproducing melamine and ammonium sulfate. The process comprises the following steps of: melting urea serving as a raw material in a urea fusion tank to form liquid urea, conveying the liquid urea into a reactor by a liquid urea washing tower, filtering reacted gas to remove impurities, condensing melamine to form a solid by a crystallizer, and conveying the solid into a cyclone separator for a finished product along with the mixed gas, discharging, cooling and packaging to obtain the melamine; and pressurizing tail gas exhausted from the top of the cyclone separator by a cold air fan to enter the liquid urea washing tower, and dividing the tail gas into three paths, wherein the first path of tail gas is pressurized by a gas carrying compressor, is used as fluidized bed carrier gas and enters the reactor; a second path of tail gas returns to the crystallizer circularly to be used as quenching gas; the third path of tail gas is separated from the gas carrying compressor, enters an ammonium sulfate saturator and reacts with sulfuric acid to generate an ammonium sulfate crystal, and the ammonium sulfate crystal is separated by a centrifugal machine to obtain an ammonium sulfate finished product; and an ammonium sulfate mother solution returns to a mother solution circulating tank to be recycled. The ammonium sulfate is large in crystalline particles, and the process is simple, easy to operate and environment-friendly, and has an obvious economic benefit.

Description

A kind of combined production of melamine ammonium sulfate process
Technical field
The present invention relates to a kind of ammonium sulfate preparation technology, be specifically related to a kind of combined production of melamine ammonium sulfate process.
Background technology
Trimeric cyanamide formal name used at school 2,4,6-triamino-1,3,5 triazines, another name melamine or melon, English name Melamine is a kind of important organic chemistry intermediates, is mainly used in production trimeric cyanamide-formaldehyde resin (MF resin).All be to be the raw material production trimeric cyanamide with urea at present in the world, the industry member custom is divided into high-pressure process and low-pressure process with Wyler's process, the most of gas phase quenching method that adopts of its technical process.But the whole flow process of high-pressure process or low-pressure process comprises that all reaction is synthetic, separates and purify and three operations of vent gas treatment.Wherein vent gas treatment is the emphasis of studying at present, and how making good use of this part tail gas economically is the gordian technique problem of Wyler's process technology.And existing ammonium sulfate production technology mainly is the clean ammonia of coke-oven gas to be produced ammonium sulfate, ammonia type flue gas desulfurizing production ammonium sulfate and deposed ammonia produce ammonium sulfate, and traditional ammonia production ammonium sulfate exists steam consumption big, and production cost is high.Simultaneously, entrainment with steam ammonia and acid mist environmental pollution are serious.
Summary of the invention
Technical problem:The invention provides a kind of combined production of melamine ammonium sulfate process, ammonium sulfate is separated out in waste heat and the ammonia and the sulfuric acid neutralization reaction thermal evaporation crystallization that make full use of melamine tail gas in the technology, and without evaporation concentration, technical process is simple, environmental protection, remarkable in economical benefits.Simultaneously, make full use of the tail gas in the Melamine Production process, reduce the pollution of tail gas environment.
Technical scheme:Raw material urea is molten into liquid urine in the urea melting groove; Send into reactor drum through liquid urine washing tower; Reacted gas through overcooling, remove by filter impurity; Trimeric cyanamide is sublimated into solid through mold, get into the finished product cyclonic separator, through discharging, cool off, be packaged to be trimeric cyanamide with gas mixture; The tail gas discharged from the cyclonic separator top, boosting through the cold air blower fan gets into liquid urine washing tower, be divided into then three the tunnel, the one tunnel through the carrier gas compressor boosts after as fluidized-bed carrier gas entering reactor drum; Another road circulation is returned mold as quenching gas; Last road is told from the carrier gas compressor and is got into the ammonium sulfate saturex; Generate ammonia sulfate crystal with sulfuric acid reaction; With extracting machine the ammonium sulfate magma is proposed from the saturex top, separate obtaining the ammonium sulfate finished product through whizzer, ammonium sulfate liquor returns the Recycling Mother Solution groove and recycles; The waste gas that saturex produces is qualified discharge after mother liquor, water two-stage washing cooling, thoroughly avoided ammonia and acid mist outside.Reaction generates in the ammonia sulfate crystal process in the ammonium sulfate saturex, adopts hot flue gases or warm air to stir, and makes reaction more abundant, and ammonium sulfate crystallization increases, and quality is good.
Beneficial effect:(1) solved the melamine tail gas recovery, and the ammonium sulfate of by-product high added value.(2) ammonium sulfate is separated out in waste heat and the ammonia and the sulfuric acid neutralization reaction thermal evaporation crystallization that make full use of tail gas in the technology, and without evaporation concentration, technical process is simple, produces easy to controlly, and facility investment is few, and energy consumption is low, environmental protection, remarkable in economical benefits.。(3) adopt hot flue gases or warm air to stir in the ammonium sulfate saturex, make reaction more abundant, ammonium sulfate crystallization increases, and quality is good, has practiced thrift a large amount of heat energy and power, has good economic benefit and environmental benefit.(4), waste gas qualified discharge after mother liquor, water two-stage washing cooling of producing of saturex, thoroughly avoided effluxing of ammonia and acid mist.
Description of drawings
Fig. 1 is a combined production of melamine ammonium sulfate process schema of the present invention.
Embodiment
Below in conjunction with accompanying drawing the present invention is done explanation further.
As shown in Figure 1; Raw material urea is sent in the urea melting groove, and through 0.45MPa saturation steam heat fused, the urea after the fusing gets into liquid urine washing tower; Mix with the high temperature liquid urine that gets off from washing tower; Mixed solution urine is through the liquid urine pump branch two-way that boosts: the one tunnel in nozzle is sent into fluidized-bed reactor as reaction raw materials, other one the tunnel gets into liquid urine scrubber overhead after liquid urine water cooler is cooled to 132-136 ℃, contact washing with circulation gas and stream and cool off.Get into the liquid urine in the reactor drum through the liquid urine pump back of boosting, under the high temperature of 0.12-0.20MPa and 380-390 ℃, through catalyst action reaction generation trimeric cyanamide.The heat of reaction needed is provided by the fused salt system, and the fluidized-bed carrier gas comes the self contained gas compressor through boosting preheating 350-400 ℃ ammonia and carbon dioxide mix gas.Reaction back gas is given birth to heat exchange through hot gas water cooler and road; Temperature is reduced to by 380 ℃ and is got into the hot gas filtration device about 320 ℃; Catalyzer in the gas and solid impurity such as high boiling point by-products produced are removed, got into mold again, after 140 ℃ of quenching gas from liquid urine washing tower mix; Gas temperature is reduced to about 210 ℃ by 320 ℃, and the trimeric cyanamide crystallization is separated out.Get into the finished product cyclonic separator with gas mixture, separator is seen off by scraper and pressure spiral in the separated cyclonic separator bottom that gathers of trimeric cyanamide, obtains the trimeric cyanamide product through cooling packing.
The gas that comes out from the cyclonic separator top, boosting through the cold air blower fan gets into liquid urine washing tower.The one, low-boiling products and unsegregated trimeric cyanamide fine powder reclaim completely with unreacted; The 2nd, about 210 ℃ gas temperature is reduced to 135-145 ℃; After the foam removal of column cyclonic separator, the first via is boosted through the carrier gas compressor and is got into reactor drum as the fluidized-bed carrier gas; The second tunnel circulation is returned mold as quenching gas; The unnecessary gas that Third Road is told from the carrier gas compressor, promptly tail gas gets into the ammonium sulfate saturex, adopts hot flue gases or warm air to stir; Make reaction more abundant; Ammonium sulfate crystallization increases, with extracting machine the ammonium sulfate magma is proposed from the saturex top, through whizzer separate the ammonium sulfate finished product.Ammonium sulfate liquor returns the Recycling Mother Solution groove and recycles.The waste gas that saturex produces is through mother liquor, the washing of water two-stage, and cooling back qualified discharge has thoroughly been avoided effluxing of ammonia and acid mist.

Claims (3)

1. combined production of melamine ammonium sulfate process; It is characterized in that: raw material urea is molten into liquid urine in the urea melting groove; Send into reactor drum through liquid urine washing tower, reacted gas through overcooling, remove by filter impurity, through mold trimeric cyanamide is sublimated into solid; Get into the finished product cyclonic separator with gas mixture, through discharging, cool off, be packaged to be trimeric cyanamide; The tail gas discharged from the cyclonic separator top, boosting through the cold air blower fan gets into liquid urine washing tower, be divided into then three the tunnel, the one tunnel through the carrier gas compressor boosts after as fluidized-bed carrier gas entering reactor drum; Another road circulation is returned mold as quenching gas; Last road is told from the carrier gas compressor and is got into the ammonium sulfate saturex; Generate ammonia sulfate crystal with sulfuric acid reaction; With extracting machine the ammonium sulfate magma is proposed from the saturex top, separate obtaining the ammonium sulfate finished product through whizzer, ammonium sulfate liquor returns the Recycling Mother Solution groove and recycles.
2. combined production of melamine ammonium sulfate process according to claim 1 is characterized in that: said in the ammonium sulfate saturex, the reaction generates in the ammonia sulfate crystal process, adopts hot flue gases or warm air to stir.
3. combined production of melamine ammonium sulfate process according to claim 1 is characterized in that: said waste gas qualified discharge after mother liquor, water two-stage washing cooling in the generation of ammonium sulfate saturex.
CN2011104526385A 2011-12-30 2011-12-30 Process for coproducing melamine and ammonium sulfate Pending CN102584731A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102887529A (en) * 2012-10-30 2013-01-23 山东沃蓝生物集团有限公司 Ammonium sulfate production system and preparation method thereof
CN114405048A (en) * 2022-02-22 2022-04-29 广东广大新能源科技有限公司 Desublimation crystallization method and system

Citations (1)

* Cited by examiner, † Cited by third party
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

Patent Citations (1)

* Cited by examiner, † Cited by third party
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

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
汤胜文: "20Kt/a氰尿酸联产40Kt/a硫酸铵工艺技术及其评价", 《中国优秀硕士学位论文全文数据库工程科技Ⅰ辑》 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102887529A (en) * 2012-10-30 2013-01-23 山东沃蓝生物集团有限公司 Ammonium sulfate production system and preparation method thereof
CN102887529B (en) * 2012-10-30 2015-05-20 山东沃蓝生物集团有限公司 Ammonium sulfate production system and preparation method thereof
CN114405048A (en) * 2022-02-22 2022-04-29 广东广大新能源科技有限公司 Desublimation crystallization method and system

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Application publication date: 20120718