CN101333197B - Method for producing melamine and co-producing ammine and ammonium hydrogen carbonate - Google Patents
Method for producing melamine and co-producing ammine and ammonium hydrogen carbonate Download PDFInfo
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- CN101333197B CN101333197B CN 200810053914 CN200810053914A CN101333197B CN 101333197 B CN101333197 B CN 101333197B CN 200810053914 CN200810053914 CN 200810053914 CN 200810053914 A CN200810053914 A CN 200810053914A CN 101333197 B CN101333197 B CN 101333197B
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Abstract
The invention provides a melamine production method for co-production of ammonia and ammonium bicarbonate; the method comprises the following steps: the melamine production process, namely, raw material is heated in a melamine reactor through molten salt and transformed into melamine, ammonia and carbon dioxide; the ammonia-carbon separation process, namely, one part of the ammonia-carbon mixture partially enters into an ammonia-carbon separation system and is heated with steam so as to obtain the carbon dioxide containing 5% of water vapor, and the pure ammonia; the aqueous solution of the other part of the ammonia-carbon mixture is added into a carbonation tower; the carbon dioxide separated from the ammonia-carbon separation system is pumped into the carbonation tower from the bottom and reacted with the aqueous solution of the ammonia-carbon mixture to generate ammonium bicarbonate. The invention has the effects that the production method enables urea to be transformed into three products with greater market demand, uses no additional chemicals and discharges no wastewater, waste gas and waste residue; the atom utilization rate is up to 100% and the production of the method belongs to clean production. Compared with the separate production of any of the three products, the method of the invention has significant technical and economic effects and environmental protection effects.
Description
Technical field
The present invention relates to the production method of trimeric cyanamide, the method for producing melamine of a kind of co-producing ammine and bicarbonate of ammonia particularly, this method is processing and the utilization to Melamine Production process by-product carbonated aqueous ammonia or ammonia/carbon dioxide mixed gas.
Background technology
Main chemical reactions take urea as the raw material production trimeric cyanamide as:
6H
2NCONH
2→C
3N
6H
6+6NH
3+3CO
2
No matter adopt which kind of explained hereafter trimeric cyanamide, the carbonic acid gas of the inevitable by-product 809.52kg ammonia simultaneously of 1 ton of product of every acquisition and 1047.62kg, and separate with trimeric cyanamide with mixed gas or aqueous solution form (below be referred to as the ammonia carbon mixture), the atom utilization of this process only has 35%.
The processing of ammonia carbon mixture is not only affected the economic benefit of enterprise, and the serious threat safety of surrounding environment.At present, most enterprises sell outward or dilute with carbonated aqueous ammonia form cheapness and efflux; What have is converted into ammonium sulfate with effect of sulfuric acid with the ammonia in the ammonia carbon mixture, effluxes carbonic acid gas; The enterprise that minority has urea plant is introduced into urea system production urea.See in theory, the latter is most economical effective means, but affects the water/carbon ratio of former urea system, and the quantity of comprehensive utilization is restricted.
Summary of the invention
The object of the present invention is to provide the method for producing melamine of a kind of co-producing ammine and bicarbonate of ammonia, the method is not being used in other any chemical situations, produces simultaneously trimeric cyanamide, pure ammonia and three kinds of products of bicarbonate of ammonia.The required material of production method of the present invention is simple, technical process flexibly, investment saving, remarkable in economical benefits, production process cleaning, atom utilization be up to 100%.
For achieving the above object, the technical scheme that the present invention takes is to provide the method for producing melamine of a kind of co-producing ammine and bicarbonate of ammonia, and the method comprises the following steps:
1, Melamine Production operation
Raw material urea is heated by fused salt in melamine reactor, is converted into trimeric cyanamide and ammonia, carbonic acid gas by following total reaction equation, obtains the ammonia carbon mixture, NH isolate trimeric cyanamide from reaction mixture after
3/ CO
2Mol ratio be 2/1,
6H
2NCONH
2→C
3N
6H
6+6NH
3+3CO
2
2, ammonia/carbon separation circuit
The ammonia carbon mixture enters the carbon dioxide separation tower of ammonia/carbon separation circuit with an aqueous solution form part, use the steam indirect heating at the bottom of tower, and tower top is isolated the carbon dioxide gas that contains 5% water vapor, obtains decarburization ammoniacal liquor at the bottom of tower;
Above-mentioned decarburization ammoniacal liquor enters Analytic Tower, and through heating thorough parsing, the solution bleed that obtains at the bottom of tower is sent to through cooling the absorption water that above-mentioned Melamine Production operation is used for the ammonia carbon mixture, and tower top obtains resolution gas;
Above-mentioned resolution gas is dry through rectifying in the ammonia rectifying tower, obtains pure ammonia gas from tower top, and a part of gas ammonia is sent to above-mentioned trimeric cyanamide operation and makes to replenish ammonia, and the liquefaction of another part gas ammonia is ammonia liquor; Isolate the ammonia soln that contains carbonic acid gas at the bottom of rectifying tower and return to the carbon dioxide separation tower;
3. bicarbonate of ammonia operation
The aqueous solution of another part ammonia carbon mixture adds carbonating tower, passes into from ammonia/isolated carbonic acid gas of carbon separation system at the bottom of carbonating tower, carries out carburizing reagent under the cooling conditions of main carbonating tower 32-38 ℃, secondary carbonating tower 25-35 ℃, makes NH
3/ CO
2Mol ratio not higher than 1/1, the bicarbonate of ammonia crystallization of generation is sent to whizzer and separates and to obtain the bicarbonate of ammonia mother liquor and return to ammonia/carbon separation system.
Effect of the present invention is that this production method becomes three kinds of products with larger market requirement with the raw material Urea Transformation, does not add other chemical, and not efflux wastewater, waste gas, waste residue, atom utilization be up to 100%, and is cleaner production.Compare during arbitrary kind in this processing method and the above-mentioned three kinds of products of independent production, all have significant techno-economic effect and environmental protection effect.
Description of drawings
Fig. 1 is the process flow sheet of the method for producing melamine of co-producing ammine of the present invention and bicarbonate of ammonia.
Embodiment
Reaching by reference to the accompanying drawings embodiment is illustrated the method for producing melamine of a kind of co-producing ammine of the present invention and bicarbonate of ammonia.
As shown in Figure 1, Melamine Production take urea as raw material has various technical processes, now take normal pressure two-step approach trimeric cyanamide as example, illustrate the method for producing melamine of a kind of co-producing ammine and bicarbonate of ammonia, but the present invention is not limited to the mode of production of this a kind of trimeric cyanamide.
1. Melamine Production
Raw material urea can add the melamine reactor 1 that catalyzer is housed in solid-state or liquid mode, and it is Urea Transformation reaction indirect heating that reactor is provided with molten salt heater; Send into the ammonia that heats through carrier gas preheater 13 from reactor bottom, make catalyzer be in fluidized state.At the temperature of 380-390 ℃, urea is converted into trimeric cyanamide and ammonia, carbonic acid gas in reactor.Resultant of reaction leaves reactor with gaseous form from the top.
Reaction generation gas removes by filter catalyst dust and the high condensation point by product of part in strainer 2 after, enter sublimate device 3-1,3-2,3-3,3-4, the 3-5 of mutual series connection, trimeric cyanamide sinks to the bottom, and regularly discharge system goes to make with extra care; Ammonia/carbon mixed air is discharged from the last step device 3-5 that sublimates.
The ammonia of discharging from the device of sublimating/carbon mixed air through the washing of ammoniacal liquor level Four, enters lyophilizer 6 in-10 ℃ of freezing dewatering at washing decarbonizing tower 5-1,5-2,5-3,5-4, obtains pure ammonia gas; Bath water is from the cooled solution bleed of ammonia/carbon separation circuit, and 5-4 adds from the washing decarbonizing tower.5-1 obtains NH from the washing decarbonizing tower
3/ CO
2Mol ratio is about 2/1 carbonated aqueous ammonia.Every tool washing decarbonizing tower is respectively equipped with ammonia circulation pump 15-1,15-2,15-3,15-4 and ammoniacal liquor water cooler 14-1,14-2,14-3,14-4.
The pure ammonia gas that lyophilize obtains is delivered to carrier gas preheater 13 through ammonia compressor 4 superchargings.
Take the ammonia that obtains from ammonia/carbon separation circuit rectifying tower 8 tops as the supply source of the gas, keep the Melamine Production system pressure and be not less than 10KPa.
2. ammonia/carbon separates
A carbonated aqueous ammonia part that obtains from the trimeric cyanamide operation near half enter ammonia water tank 16 and liquid at the bottom of ammonia rectifying tower 8 towers, the bicarbonate of ammonia mother liquor is mixed, deliver to carbon dioxide separation tower 9 through topping-up pump 17 superchargings, use steam through reboiler 18 indirect heating at the bottom of tower, tower top is isolated the carbon dioxide gas that contains a small amount of water vapor, obtains decarburization ammoniacal liquor at the bottom of tower.
Decarburization ammoniacal liquor enters Analytic Tower 11, through heating thorough parsing, what get at the bottom of tower sends into carbon dioxide separation tower 9 to a desorb water part through pump 19, and another part enters and is sent to the absorption water that the trimeric cyanamide operation is used as the ammonia carbon mixture after water cooler 20 cools, and tower top obtains resolution gas.
Resolution gas is interior dry through rectifying at ammonia rectifying tower 8, obtains pure ammonia gas from tower top, and a small part gas ammonia is sent to the trimeric cyanamide operation and makes to replenish ammonia, enters condenser 10 after compressed machine 7 compressions of most of gas ammonia, and gas ammonia is liquefied and is ammonia liquor; Rectifying tower is low to be isolated the ammonia soln that contains carbonic acid gas and delivers to ammonia water tank 17 and return to the carbon dioxide separation tower.
3. bicarbonate of ammonia operation
Above-mentioned second half carbonated aqueous ammonia adds alternately as in major and minor carbonating tower 12-1,12-2 two towers, pass into from ammonia/isolated carbonic acid gas of carbon separation circuit at the bottom of carbonating tower, at main carbonating tower 32-38 ℃, under the cooling conditions of secondary carbonating tower 25-35 ℃, carry out carburizing reagent, make NH
3/ CO
2Mol ratio not higher than 1/1, the bicarbonate of ammonia crystallization of generation is sent to whizzer 21 and carries out solid/liquid separation, isolated mother liquor is sent into the carbon separation system; Isolated bicarbonate of ammonia is sold through packing.
The method for producing melamine of a kind of co-producing ammine and bicarbonate of ammonia, every input 3.2-3.3 ton urea, but 1 ton of trimeric cyanamide of output, 400Kg liquefied ammonia, 1.8 tons of bicarbonate of ammonia.1 ton, consume fuel coal, 1.0MPa steam 9-10 ton.Whole process is discharge technology gas and process liquid not.
Claims (1)
1. the method for producing melamine of a co-producing ammine and bicarbonate of ammonia, the method comprises the following steps:
1., Melamine Production operation
Raw material urea adds the melamine reactor (1) that catalyzer is housed in solid-state or liquid mode, it is Urea Transformation reaction indirect heating that reactor (1) is provided with molten salt heater; Send into the ammonia that heats through carrier gas preheater (13) bottom reactor (1), make catalyzer be in fluidized state, at the temperature of 380-390 ℃, urea is converted into trimeric cyanamide and ammonia, carbonic acid gas in reactor, and resultant of reaction leaves reactor with gaseous form from the top;
Reaction generation gas removes by filter catalyst dust and the high condensation point by product of part in strainer (2) after, the first step that enters mutual series connection device (3-1), second stage device (3-2), third stage device (3-3), fourth stage device (3-4), the last step device (3-5) of sublimating of sublimating of sublimating of sublimating of sublimating, sink to the bottom, regularly discharge system goes to make with extra care; Ammonia/carbon mixed air is discharged from the last step device (3-5) of sublimating;
The ammonia of discharging from the device of sublimating/carbon mixed air washs through the ammoniacal liquor level Four at the first washing decarbonizing tower (5-1), the second washing decarbonizing tower (5-2), the 3rd washing decarbonizing tower (5-3), the 4th washing decarbonizing tower (5-4), enter lyophilizer (6) in-10 ℃ of freezing dewatering, obtain pure ammonia gas; Bath water adds from the 4th washing decarbonizing tower (5-4) from the cooled solution bleed of ammonia/carbon separation circuit; Obtain NH from the first washing decarbonizing tower (5-1)
3/ CO
2Mol ratio is 2/1 carbonated aqueous ammonia, and every tool washing decarbonizing tower is respectively equipped with ammonia circulation pump and ammoniacal liquor water cooler;
The pure ammonia gas that lyophilize obtains is delivered to carrier gas preheater (13) through ammonia compressor (4) supercharging, take the ammonia that obtains from ammonia/carbon separation circuit rectifying tower (8) top as the supply source of the gas, keep the Melamine Production system pressure and be not less than 10Kpa;
2., ammonia/carbon separation circuit
The carbonated aqueous ammonia near half that obtains from above-mentioned Melamine Production operation enters ammonia water tank (16) and liquid at the bottom of ammonia rectifying tower (8) tower, the bicarbonate of ammonia mother liquor is mixed, deliver to carbon dioxide separation tower (9) through topping-up pump (17) supercharging, use steam through reboiler (18) indirect heating at the bottom of tower, tower top is isolated the carbon dioxide gas that contains a small amount of water vapor, obtains decarburization ammoniacal liquor at the bottom of tower;
Above-mentioned decarburization ammoniacal liquor enters Analytic Tower (11), through heating thorough parsing, a solution bleed part that obtains at the bottom of tower is sent into carbon dioxide separation tower (9) through pump (19), another part enters and is sent to the absorption water that the trimeric cyanamide operation is used as the ammonia carbon mixture after water cooler (20) cools, and the tower top of Analytic Tower (11) obtains resolution gas;
Above-mentioned resolution gas is dry through rectifying in ammonia rectifying tower (8), obtain pure ammonia gas from tower top, part gas ammonia is sent to above-mentioned trimeric cyanamide operation as replenishing ammonia, the liquefaction of another part gas ammonia is isolated the ammonia soln that contains carbonic acid gas and is returned to the carbon dioxide separation tower for ammonia liquor at the bottom of ammonia rectifying tower (8) tower;
3., bicarbonate of ammonia operation
Second half carbonated aqueous ammonia that obtains from above-mentioned Melamine Production operation adds carbonating tower, pass into from ammonia/isolated carbonic acid gas of carbon separation system at the bottom of carbonating tower, under the cooling conditions of main carbonating tower 32-38 ℃, secondary carbonating tower 25-35 ℃, carry out carburizing reagent, make NH
3/ CO
2Mol ratio not higher than 1/1, the bicarbonate of ammonia crystallization of generation separates through whizzer, obtains the bicarbonate of ammonia mother liquor and sends ammonia/carbon separation system back to.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200810053914 CN101333197B (en) | 2008-07-22 | 2008-07-22 | Method for producing melamine and co-producing ammine and ammonium hydrogen carbonate |
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|---|---|---|---|
| CN 200810053914 CN101333197B (en) | 2008-07-22 | 2008-07-22 | Method for producing melamine and co-producing ammine and ammonium hydrogen carbonate |
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| CN101333197B true CN101333197B (en) | 2013-06-19 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106608647A (en) * | 2015-10-26 | 2017-05-03 | 安徽华尔泰化工股份有限公司 | Melamine byproduct ammonium hydroxide treatment device |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101862577A (en) * | 2009-06-12 | 2010-10-20 | 河南骏化发展股份有限公司 | Method for reclaiming melamine tail gas |
| CN101979385A (en) * | 2010-10-26 | 2011-02-23 | 丁泽华 | Method for co-producing melamine, nitric acid and ammonium nitrate |
| CN102897796A (en) * | 2011-07-25 | 2013-01-30 | 山东华鲁恒升化工股份有限公司 | Clean production method for co-production of ammonium bicarbonate through combination of high purity carbon dioxide and melamine tail gas |
| CN102538394B (en) * | 2011-12-27 | 2014-08-06 | 尤彪 | Method for separating ammonia and carbon dioxide by low-temperature rectification |
| CN105084328B (en) * | 2014-05-16 | 2017-06-30 | 沈阳化工研究院有限公司 | A kind of method that Amcide Ammate is produced using the waste gas containing ammonia and carbon dioxide |
| CN109467105A (en) * | 2018-12-14 | 2019-03-15 | 四川金象赛瑞化工股份有限公司 | The production method and process units of ammonium hydrogen carbonate |
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2008
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106608647A (en) * | 2015-10-26 | 2017-05-03 | 安徽华尔泰化工股份有限公司 | Melamine byproduct ammonium hydroxide treatment device |
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