CN104356029A - Urea synthetic method - Google Patents
Urea synthetic method Download PDFInfo
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- CN104356029A CN104356029A CN201410579140.9A CN201410579140A CN104356029A CN 104356029 A CN104356029 A CN 104356029A CN 201410579140 A CN201410579140 A CN 201410579140A CN 104356029 A CN104356029 A CN 104356029A
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- urea
- ammonia
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Abstract
The invention relates to a urea synthetic method which comprises the following steps: compression of raw material ammonia and carbon dioxide; synthesizing and gas stripping; medium and low pressure decomposition and recovery process; evaporation and pelletizing of urine. The method disclosed by the invention is simple, is low in cost and has a high synthesizing speed; obtained urea particles are uniform, have low impurity content, are moderate to dissolve and can be sufficiently adsorbed by crops more easily; moreover, an adsorption tower is utilized to treat tail gas, so that the synthesizing process is more environmental-friendly.
Description
Technical field
The present invention relates to technical field of chemical synthesis, particularly relate to a kind of urea synthesis method.
Background technology
Urea, also known as carboxamide (carbamide), is a kind of white crystal.One of the simplest organic compound.The diamide of carbonic acid, molecular formula is H
2nCONH
2(CO (NH
2)
2).The main nitrogenous end product of Mammals and some Fish internal protein metabolic breakdown.Also be the nitrogenous fertilizer that current nitrogen content is the highest.As a kind of neutral fertilizer, urea is applicable to various soil and plant.It is easily preserved, easy to use, little to the destruction of soil, is a kind of chemical nitrogen fertilizer that current usage quantity is larger.Industrial ammonia and carbonic acid gas urea synthesis under certain condition.
At present, mainly there is following problem in synthesis process of urea: method is complicated, cost is higher, production capacity is low, and the problem such as to have greater environmental impacts.
Summary of the invention
It is simple, with low cost that technical problem to be solved by this invention is to provide a kind of method, synthesis fast, the urea granules obtained is even, impurity is few, dissolve the abundant absorption that appropriateness is conducive to crop, and utilize absorption tower to process tail gas, make the urea synthesis method of building-up process environmental protection more.
The technical scheme that the present invention solves the problems of the technologies described above is as follows: a kind of urea synthesis method, comprises the steps:
The compression of raw material ammonia and carbonic acid gas;
Synthesis and air lift;
Mesolow decomposes and recovery process;
The evaporation of urine and granulation.
On the basis of technique scheme, the present invention can also do following improvement.
Further, being implemented as follows of compression step of described raw material ammonia and carbonic acid gas:
Raw materials ammonia is supplied by synthetic ammonia workshop, after entering urea plant, after ammonia preheater, enters high-pressure ammonia pump; The temperature that need control liquefied ammonia in order to avoid liquid ammonia gasification is lower 5 ~ 12 DEG C than the boiling point after ammonia pump pressure-raising; Unstripped gas CO
2send into bottom synthetic tower and gas stripping column after carbon dioxide compressor compression.
Further, being implemented as follows of described synthesis and stripping step:
The raw materials ammonia that synthetic ammonia installation comes is through boosting and the laggard urea synthesizer of preheating; Raw material CO
2h is removed through dehydrogenation reactor
2after, then through overdraft, most CO
2send stripping tower to make stripping fluid, rest part then send urea tower urea synthesis; After reaching high transformation efficiency, urea enters stripping tower, passes through CO
2stripping; Unreacted first ammonium decomposition in urea soln and excess of ammonia stripping are out entered carbamate condenser afterwards, and the urea soln after stripping delivers to purification process; Carbamate condenser gas out then enters high-pressure absorber water cooler further and reclaims NH further
3and CO
2, bottom carbamate condenser, first ammonium solution out enters urea synthesizer by high pressure methylamine injector.
Further, described mesolow decomposes and being implemented as follows of recovery process step:
The urea soln come from synthesis procedure enters lst-stage precipitation tower, is made a part of NH in liquid phase by urea self heat
3and CO
2be desorbed out, and then make first ammonium resolve into the NH of gas phase by the heat of middle pressure steam
3and CO
2, then enter one section of absorber cooler; To make the NH urea soln further through two sections of solution decomposes towers from lst-stage precipitation tower urea soln out
3and CO
2be down to 0.7% and 0.5%; Deliver to after condensation, flash distillation from two sections of decomposition towers urea soln out and steam contracting operation.
Further, the evaporation of described urine and being implemented as follows of granulation step:
Urea soln from purification process through being pre-compressed to about 70%wt, then enters evaporization process, after two sections of operations evaporations, send prilling tower to produce granular urea product; The water vapor be evaporated, enters final thickener surface cooler, delivers to process condensate treatment process after condensation; Be separated in the separator from vaporizer liquid-vapor mixture out, gas phase delivers to process condensate treatment process after condensation.
The invention has the beneficial effects as follows: method is simple, with low cost, fast, the urea granules of acquisition is even, impurity is few in synthesis, dissolves the abundant absorption that appropriateness is conducive to crop, and utilizes absorption tower to process tail gas, make building-up process environmental protection more
Accompanying drawing explanation
Fig. 1 is a kind of urea synthesis method schematic flow sheet of the present invention.
Embodiment
Be described principle of the present invention and feature below in conjunction with accompanying drawing, example, only for explaining the present invention, is not intended to limit scope of the present invention.
As shown in Figure 1, a kind of urea synthesis method, comprises the steps:
Raw materials ammonia is supplied by synthetic ammonia workshop, after entering urea plant, after ammonia preheater, enters high-pressure ammonia pump; The temperature that need control liquefied ammonia in order to avoid liquid ammonia gasification is lower 5 ~ 12 DEG C than the boiling point after ammonia pump pressure-raising; Unstripped gas CO
2send into bottom synthetic tower and gas stripping column after carbon dioxide compressor compression.The raw materials ammonia that synthetic ammonia installation comes is through boosting and the laggard urea synthesizer of preheating; Raw material CO
2h is removed through dehydrogenation reactor
2after, then through overdraft, most CO
2send stripping tower to make stripping fluid, rest part then send urea tower urea synthesis; After reaching high transformation efficiency, urea enters stripping tower, passes through CO
2stripping; Unreacted first ammonium decomposition in urea soln and excess of ammonia stripping are out entered carbamate condenser afterwards, and the urea soln after stripping delivers to purification process; Carbamate condenser gas out then enters high-pressure absorber water cooler further and reclaims NH further
3and CO
2, bottom carbamate condenser, first ammonium solution out enters urea synthesizer by high pressure methylamine injector.
The urea soln come from synthesis procedure enters lst-stage precipitation tower, is made a part of NH in liquid phase by urea self heat
3and CO
2be desorbed out, and then make first ammonium resolve into the NH of gas phase by the heat of middle pressure steam
3and CO
2, then enter one section of absorber cooler; To make the NH urea soln further through two sections of solution decomposes towers from lst-stage precipitation tower urea soln out
3and CO
2be down to 0.7% and 0.5%; Deliver to after condensation, flash distillation from two sections of decomposition towers urea soln out and steam contracting operation.
Urea soln from purification process through being pre-compressed to about 70%wt, then enters evaporization process, after two sections of operations evaporations, send prilling tower to produce granular urea product; The water vapor be evaporated, enters final thickener surface cooler, delivers to process condensate treatment process after condensation; Be separated in the separator from vaporizer liquid-vapor mixture out, gas phase delivers to process condensate treatment process after condensation.
The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (5)
1. a urea synthesis method, is characterized in that, comprises the steps:
The compression of raw material ammonia and carbonic acid gas;
Synthesis and air lift;
Mesolow decomposes and recovery process;
The evaporation of urine and granulation.
2. a kind of urea synthesis method according to claim 1, is characterized in that, being implemented as follows of the compression step of described raw material ammonia and carbonic acid gas:
Raw materials ammonia is supplied by synthetic ammonia workshop, after entering urea plant, after ammonia preheater, enters high-pressure ammonia pump; The temperature that need control liquefied ammonia in order to avoid liquid ammonia gasification is lower 5 ~ 12 DEG C than the boiling point after ammonia pump pressure-raising; Unstripped gas CO
2send into bottom synthetic tower and gas stripping column after carbon dioxide compressor compression.
3. a kind of urea synthesis method according to claim 1, is characterized in that, being implemented as follows of described synthesis and stripping step:
The raw materials ammonia that synthetic ammonia installation comes is through boosting and the laggard urea synthesizer of preheating; Raw material CO
2h is removed through dehydrogenation reactor
2after, then through overdraft, most CO
2send stripping tower to make stripping fluid, rest part then send urea tower urea synthesis; After reaching high transformation efficiency, urea enters stripping tower, passes through CO
2stripping; Unreacted first ammonium decomposition in urea soln and excess of ammonia stripping are out entered carbamate condenser afterwards, and the urea soln after stripping delivers to purification process; Carbamate condenser gas out then enters high-pressure absorber water cooler further and reclaims NH further
3and CO
2, bottom carbamate condenser, first ammonium solution out enters urea synthesizer by high pressure methylamine injector.
4. a kind of urea synthesis method according to claim 1, is characterized in that, described mesolow decomposes and being implemented as follows of recovery process step:
The urea soln come from synthesis procedure enters lst-stage precipitation tower, is made a part of NH in liquid phase by urea self heat
3and CO
2be desorbed out, and then make first ammonium resolve into the NH of gas phase by the heat of middle pressure steam
3and CO
2, then enter one section of absorber cooler; To make the NH urea soln further through two sections of solution decomposes towers from lst-stage precipitation tower urea soln out
3and CO
2be down to 0.7% and 0.5%; Deliver to after condensation, flash distillation from two sections of decomposition towers urea soln out and steam contracting operation.
5. a kind of urea synthesis method according to claim 1, is characterized in that, the evaporation of described urine and being implemented as follows of granulation step:
Urea soln from purification process through being pre-compressed to about 70%wt, then enters evaporization process, after two sections of operations evaporations, send prilling tower to produce granular urea product; The water vapor be evaporated, enters final thickener surface cooler, delivers to process condensate treatment process after condensation; Be separated in the separator from vaporizer liquid-vapor mixture out, gas phase delivers to process condensate treatment process after condensation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410579140.9A CN104356029A (en) | 2014-10-25 | 2014-10-25 | Urea synthetic method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410579140.9A CN104356029A (en) | 2014-10-25 | 2014-10-25 | Urea synthetic method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104356029A true CN104356029A (en) | 2015-02-18 |
Family
ID=52523366
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410579140.9A Pending CN104356029A (en) | 2014-10-25 | 2014-10-25 | Urea synthetic method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104973891A (en) * | 2015-06-09 | 2015-10-14 | 安徽淮化股份有限公司 | Two urea device-combined device for producing UAN liquid nitrogen fertilizer and use method thereof |
| CN110041230A (en) * | 2019-04-30 | 2019-07-23 | 中国五环工程有限公司 | Recycle the vaporizing extract process urea production process of melamine plant tail gas |
| CN113416154A (en) * | 2021-07-30 | 2021-09-21 | 新疆心连心能源化工有限公司 | Urea synthesis unreacted substance recycling method and device |
| CN114432839A (en) * | 2022-03-08 | 2022-05-06 | 产学研(广州)环境服务有限公司 | Double-carbon treatment carbon capture recycling system and method |
-
2014
- 2014-10-25 CN CN201410579140.9A patent/CN104356029A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104973891A (en) * | 2015-06-09 | 2015-10-14 | 安徽淮化股份有限公司 | Two urea device-combined device for producing UAN liquid nitrogen fertilizer and use method thereof |
| CN104973891B (en) * | 2015-06-09 | 2018-06-15 | 安徽淮化股份有限公司 | The device and its application method of two sets of urea plant Joint Production UAN liquid nitrogen fertilizer |
| CN110041230A (en) * | 2019-04-30 | 2019-07-23 | 中国五环工程有限公司 | Recycle the vaporizing extract process urea production process of melamine plant tail gas |
| CN110041230B (en) * | 2019-04-30 | 2021-10-15 | 中国五环工程有限公司 | Process for producing urea by stripping method for recovering tail gas of melamine device |
| CN113416154A (en) * | 2021-07-30 | 2021-09-21 | 新疆心连心能源化工有限公司 | Urea synthesis unreacted substance recycling method and device |
| CN113416154B (en) * | 2021-07-30 | 2023-01-17 | 新疆心连心能源化工有限公司 | Urea synthesis unreacted substance recycling method and device |
| CN114432839A (en) * | 2022-03-08 | 2022-05-06 | 产学研(广州)环境服务有限公司 | Double-carbon treatment carbon capture recycling system and method |
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| C06 | Publication | ||
| PB01 | Publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20150218 |
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| WD01 | Invention patent application deemed withdrawn after publication |