CN1058704C - Method for prepn. of urea by carbon dioxide stripping method - Google Patents
Method for prepn. of urea by carbon dioxide stripping method Download PDFInfo
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- CN1058704C CN1058704C CN96116210A CN96116210A CN1058704C CN 1058704 C CN1058704 C CN 1058704C CN 96116210 A CN96116210 A CN 96116210A CN 96116210 A CN96116210 A CN 96116210A CN 1058704 C CN1058704 C CN 1058704C
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Abstract
The present invention relates to a method for preparing urea by a carbon dioxide stripping method from ammonia in coke oven gas. The method develops a new approach for recovering the ammonia from the coke oven gas in metallurgy industry. Recovered anhydrous ammonia is used as a raw material. The method is an economic and reasonable technological process for producing the urea, and is suitable for small scale urea production. The method solves the outlet problem of liquid ammonia in a coke oven plant; the method not only prevents environmental pollution, but also produces fertilizers for supporting agricultural production. The method has the characteristics of simple process, investment saving, less floor space and convenient operation and management. Compared with a carbon dioxide stripping method of a Holland stamicarbon company, the quantity of equipment can be reduced by 15%, and the investment can be reduced by 10%.
Description
The present invention belongs to the liquefied ammonia that reclaims carbon dioxide stripping process urea production method from coke-oven gas.
In prior art, a lot of process for producing urea are arranged both at home and abroad, mainly contain aqueous solution circulation method, high pressure CO
2Vaporizing extract process and ammonia vaporizing extract process.Aqueous solution circulation method is the state of the art in the sixties, and domestic middle scale nitrogenous fertilizer plant all is to adopt this method, and this method technical process is complicated, and production process is many, and equipment is many, invest higherly, and abroad newly-built urea plant has no longer adopted this method.High pressure CO
2Vaporizing extract process is one of current advanced flow process, in the Dutch Stamicarbon company urea production process, adopts CO
2The stripping pressure of stripping flow process is 14MPa, and stripping and condensation under higher pressure though help energy recovery, reduce steam consumption, and steam stripping efficiency is poor, NH in the urine behind the stripping
3And CO
2Content is respectively 8% and 10%, thus must establish the low pressure decomposing system, could be with the NH of remainder
3And CO
2Reclaim.Whole flow sheet equipment is many, investment is high, operational requirement is also high.Also will use some special stainless steels, domestic can not production needs dependence on import at present, and be also all higher to the requirement of equipment installation, debugging and operational administrative.This flow process is not suitable for small-sized urea plant, and to be lower than 150t/d just very economical when scale.
The ammonia vaporizing extract process is the exploitation of Italian SNAM company, and integrated mill adopts morely in the world at present, produces 1000～1500 tons of urea daily.In recent years China will introduce many covers.This method energy consumption is low, does not need high-rise frame, so the cost of urea product is also low.But this method flow process is longer, and high-tension apparatus is many, needs special titanium material, and control requires also complicated, so should not adopt at small-sized urea plant.
Having the objective of the invention is to start a kind of new way that reclaims ammonia in the coke(oven)gas of utilizing, is raw material with the anhydrous ammonia that reclaims, and seeks not only economy but also rational operational path production urea, is fit to the factory that makes urea of small-sized scale.
Another object of the present invention is to belong to the disposal of three wastes, in order to solve the problem of outlet of coke-oven plant's liquefied ammonia, has not only prevented environmental pollution but also produce fertilizer and supported agriculture production.
Will produce urea and belong to the by-product comprehensive utilization from reclaiming ammonia in the coke-oven plant, require flow process short, equipment be few, invest low, the production method of convenient operation and control, CO of the present invention
2Vaporizing extract process urea production method can satisfy these requirements.
Below in conjunction with detailed description and the description of the drawings thereof, preparation method of the present invention, technical process and advantage thereof are done a detailed introduction to technical scheme of the present invention.
The accompanying drawing of this specification sheets is the process flow sheet of carbon dioxide stripping process urea production method.
As shown in the figure, raw materials ammonia 31 is through high-pressure ammonia pump 15 and liquefied ammonia heater 13, amino first Acid ammonium (being called for short the first ammonium) liquid 34 heats through high pressure carbamate pump 16 and first ammonium liquid heater 14, supercharging After enter urea synthesizer 1 bottom. Under pressure 20～22MPa, 185～190 ℃ of conditions of temperature, advance The row reaction. Production intensity in the tower is 8.4～10.5t/m3D. In order to prevent the back-mixing of reaction mass, Be provided with some sieve plates with holes in urea synthesizer 1, its aperture is Φ 7～9mm, percent opening Being 2～3%, is to be provided with 2～6 sieve plates in the best urea synthesizer 1. The lining of urea synthesizer Material is modified form 316L.
NH in urea synthesizer 13/CO
2(molecular proportion)=4.5～5, this value can not be too high, no Then a large amount of ammonia will circulate. H in the tower2O/CO
2(molecular proportion)=0.9～1.2, the smaller the better at this steam/hydrocarbons ratio, can improve conversion rate of urea, 62.5% CO is arranged approximately2Change into urea. After the synthetic reaction Urea melt 35 draw on tower top, be decompressed to through automatic pressure-reducing control valve 24 3.0～4.0MPa enters the CO with liquid distributor2The top of stripper 2. Urea melt Be to pass through earlier sieve plate, then enter not susceptible to plugging zigzag distributor and enter equably tubulation, edge Inwall becomes membranaceous and flows downward.
CO after compression2Gas 32 is sent into CO2The bottom of stripper 2, with the tubulation inwall to Urea melt 35 counter current contacting of current downflow. Stripper heats with steam 27, condensate liquid 28 rows Put. Make superfluous ammonia in the solution and first ammonium under the condition of heating, descending with liquid steams or divides Separate, the temperature of solution is 155～160 ℃ in the tubulation.
At CO2Be provided with sieve plate in the stripper, its aperture is Φ 7～9mm, and percent opening is 5～25%. Tower top is provided with two sieve plates, makes gas-liquid contact to reduce the water content in the exit gas. The tower bottom If a sieve plate carries out adiabatic stripping, further improve steam stripping efficiency. CO2Stripper 2 is two sections tubulations or single hop tubulation falling-film tower, and the peripheral flow rate in the tower is 500～750kg/mh, and Coefficient K is 1400～1600KJ/m2·h·℃。CO
2The tubulation of stripper and cylinder material all adopt modified form 316L.
The NH that comes out from the stripping tower top
3, CO
2, mixed gass 36 such as water vapor, rare gas element generate dense first ammonium liquid 34 when carbamate condenser 17 with after the first ammonium liquid 33 of absorption tower 4 outlet at bottoms mixes, be back to urea synthesizer 1, do not absorb gas 53 through high pressure carbamate pump 16, first ammonium liquid well heater 14 from passing through absorption tower 4 down.Condensation absorbs in the tubulation of the interior cold or external cooling of absorption tower hypomere, makes most of CO
2And NH
3Reaction generates first ammonium solution, a spot of CO
2The NH that sprays into cat head in space segment in the middle part of tower and the top packing layer
3The water counter current contact is to reach the purpose of fine purifiation.The pressure on absorption tower 4 is that 3.0～4.0MPa, 110～120 ℃ of column bottom temperatures, tower top temperature are 70～80 ℃, and the superficial velocity in the tower is 0.02～0.03m/s, and Coefficient K is 1800～2400KJ/m
2H ℃, the NH of first ammonium liquid in the tower
3/ CO
2(molecular ratio)=2.4～2.6, H
2O/CO
2(molecular ratio)=0.9～1.2.
From CO
2The urea soln 41 that draw stripping tower 2 bottoms, by automatic regulating valve 25 decompressions, material enters flash heater 6, flash separator 7, flash condenser 8 successively.
The pressure of flash heater 6 is that 0.06～0.1MPa, Heating temperature are 100～110 ℃, and the Coefficient K of flash heater is 1600～2000KJ/m
2H ℃.When urea soln 41 passes through flash heater 6,, make the remaining NH in the urine by steam 27 heating back phlegmas 28 dischargings
3, CO
2Further driven out of, urea content increases to 65～75% (weight) in the flash distillation outlet urine, and flash distillation first ammonium rate of decomposition is 97～99%, and the total ammonia steam rate of flash distillation is 99～99.5%.
Gas and liquid mixture 42 gas 44 after flash separator 7, flash distillation advances flash condenser 8 after the flash distillation of coming out in flash heater 6 tops, NH in the condensed flash distillation phlegma 45
3Be 16～18% (weight), CO
2Be 14～16% (weight).The flash distillation phlegma is put to flash distillation condensation liquid bath 19, squeezes into 4 middle parts, absorption tower with flash distillation condensate pump 18 again.The condensed uncondensed gas 46 of flash distillation vacuumizes the back emptying by vacuum apparatus 12.
From the absorption tower 4 top exits contain ammonia gas 37, be introduced into ammonia condenser 23 condensations, condensed liquefied ammonia 31 is through liquefied ammonia medial launder 3,4 tops, absorption tower of refluxing are as absorption agent.The uncooled ammonia gas 38 that contains enters 5 cleanings of ammonia cleanser again, makes most gas ammonia by soft water 29 washing and recycling, absorbs liberated heat and is removed by water coolant 30.Pressure recovery is 3.0～4.0MPa, and temperature is 30～40 ℃.Being horizontal heat exchanger below the ammonia cleanser 5, is packing tower above, and its Coefficient K is 800～1200KJ/m
2H ℃.Clean NH in the outlet at bottom ammoniacal liquor 39 of back
3Be 10～15% (weight), this part ammoniacal liquor is back to 4 tops, absorption tower as absorption agent.CO in the gas 40 of tower top outlet after cleaning
2＜100ppm, NH
3Be 2～4g/Nm
3, then through decompression valve 26 emptying automatically.
First from the evaporation condensate 47 that evaporation equipment 11 comes out to evaporation condensate storage tank 22, after boosting, divide by evaporative condenser liquid pump 21 two the tunnel to advance ammonia still 9 again, wherein one the tunnel is as the cat head charging, 35～45 ℃ of cat head chargings, another road be through interchanger 20 make the part evaporation condensate be heated to 90～100 ℃ as tower in charging.At the bottom of the ammonia still process pressure column of ammonia still 9 is 0.12～0.14MPa, and cat head is 0.09～0.1MPa, is 105～110 ℃ at the bottom of the ammonia still process temperature tower, and cat head is 80～90 ℃, is heated with steam 27 by the ammonia still bottom.After the ammonia still process at the bottom of the tower waste liquid 48 emit behind interchanger 20 at the bottom of by the ammonia still process Tata and enter trench.Contain NH in the ammonia still 9 tower top outlet gases 52
3, CO
2And H
2O advances condensation in the flash condenser 8.
Ammonia in the coke-oven gas was mainly used to produce ammoniacal liquor in the past, because the cost height, sale price is low, and ammoniacal liquor per ton all will lose.In recent years, because the ammoniacal liquor requirement descends year by year, seriously unsalable during dull season, the factory's ammoniacal liquor swell-warehouse that has is had to outside discharging, thereby causes serious environmental to pollute.
The present invention can be metallurgy industry and effectively utilizes byproduct to open up a new way.Be applicable to that the coke-oven plant of each Iron And Steel Company reclaims the comprehensive utilization of ammonia.Ammonia in the coke-oven gas is produced liquefied ammonia, and the production cost of this liquefied ammonia is lower than the production cost of general small nitrogenous fertilizer plant, again with this liquefied ammonia as the raw material of producing urea, another main raw material CO of production urea
2, be to utilize in the large quantity of exhaust gas of the generation after the gas heating burning to contain 10～20%CO
2Stack gas, can be with CO in this waste gas
2Be used, this is not only economy but also rational operational path, is fit to small-scale urea production.
The present invention makes ammonia and the stack gas in the coke-oven gas obtain comprehensive utilization, can produce urea, has supported agriculture production, can prevent three-waste pollution again, improves envrionment conditions.
The present invention has that flow process is simple, investment economizes, floor space is few, the CO of the characteristics of operation and convenient management and Dutch Stamicarbon company
2Vaporizing extract process is compared and can be reduced investment about 10%.Because two sections decomposing systems in the traditional process have been saved in the raising of steam stripping efficiency of the present invention, so equipment reduces.Because working pressure reduces greatly, thus just not high to the requirement of material, the CO of the more Dutch Stamicarbon of the quantity of equipment company
2Vaporizing extract process is compared and is reduced about 15%.But equipment centralized arrangement of the present invention in two buildingss, only 23 meters of main frame height, and the CO of Dutch Stamicarbon company
2The vaporizing extract process main frame needs 70 meters height.Operating post reduces because of the flow sheet equipment simplification in the urea method for making of the present invention, is convenient to operational administrative.
Because CO of the present invention
2The required stripping Heating temperature of stripping is lower than 160 ℃, and the temperature that the general just urea of this temperature can bear with stainless steel is so needn't adopt high pressure CO
2The special stainless steel that stripping is required.
The present invention also extends to little synthesis ammonia plant, utilizes the NH of synthesis ammonia plant
3, CO
2Be raw material, can produce the granular urea product with method of the present invention.
Illustrate the present invention with embodiment below, but and do not mean that restriction the present invention.
Embodiment 1:
Urea synthesizer Φ 800 * 11500mm, CO
2Stripping tower Φ 500 * 11700mm, absorption tower Φ 700 * 9600mm, flash heater Φ 273 * 2700mm, ammonia cleanser Φ 325 * 2000mm, ammonia still Φ 273 * 11200, raw materials ammonia 1032.5kg/h, CO
2Tolerance is 696.48Nm
3/ h.Liquefied ammonia and circulation ammonia are heated to 180 ℃ of degree and enter urea synthesizer, and first ammonium liquid is heated to 180 ℃ and enters urea synthesizer.NH in the synthetic tower inlet feed
31596.56kg/h, first ammonium liquid 4942.32kg/h.NH
3/ CO
2(molecular ratio)=4.5, H
2O/CO
2(molecular ratio)=1.1.Pressure P=20MPa in the tower, temperature t=183 ℃.CO
2Transformation efficiency 62.5%.
Enter CO after the decompression of urea synthesizer outlet melts
2Stripping tower is with P=3.5MPa, 99% CO
2Gas, tolerance are 696.48m
3/ h (wherein contains O
20.7%) carries out stripping.Pressure of stripping tower P=32MPa, temperature t=155 ℃, use steam heating.Total ammonia goes out rate 95.8%, first ammonium rate of decomposition 85.5% in the tower.
Contain urea 56.77%, NH in the urea soln of stripping tower outlet at bottom
33.52%, CO
23.63%.Enter flash heater after the decompression.The flash heater steam heating, total ammonia steam rate 99.37% under pressure P=0.066MPa, temperature t=105 ℃ condition, methylamine rate of decomposition 97.08%, the outlet urine concentration is 70% after the flash distillation.
The NH that comes out in the stripping tower top
3, CO
2Enter the absorption tower Deng mixed gas, the pressure P=3.1MPa on absorption tower, midsection add the flash distillation phlegma, the weak ammonia that cat head adds liquefied ammonia and comes from the ammonia cleanser.First ammonium temperature t at the bottom of 78 ℃ of tower top temperatures, the tower=110 ℃ absorbs the heat that produces and is removed by water coolant.Contain NH in the first ammonium liquid in the tower
340.46%, CO
242.07%, NH
3/ CO
2(molecular ratio)=2.5, H
2O/CO
2(molecular ratio)=1.1.
The first ammonium liquid that comes out in the bottom, absorption tower is forced into 20MPa with high pressure carbamate pump, adds 17.5Nm therein
3The air of/h, reheat to 180 ℃ enter urea synthesizer.
The absorption tower top exit contains and contains a large amount of NH in the ammonia gas
3, CO
2＜100ppm, with the gas ammonia condensation, liquefied ammonia passes back into the absorption tower through ammonia condenser in elder generation.Uncondensed gas enters the ammonia cleanser, with soft water washing, 35 ℃ of pressure P=3.3MPa, temperature down operation make 13.4% weak ammonia and pass back into the absorption tower, tail gas emptying compliance with environmental protection requirements.
70% urine of coming out from the flash separator bottom enters evaporation equipment, and the urine concentration behind two-stage evaporation reaches 99.5%, is solidified into granular urea product 1750kg/h at the granulating equipment internal cooling.
The total ammonia utilization ratio of present embodiment is 96.05%.
Embodiment 2:
Equipment and the flow process identical with embodiment 1, raw materials ammonia 1228.50kg/h, CO
2Tolerance is 835.28Nm
3/ h.Liquefied ammonia and circulation ammonia are heated to 183 ℃ and enter urea synthesizer, and first ammonium liquid is heated to 183 ℃ and enters urea synthesizer.NH in the synthetic tower inlet feed
31915.87kg/h, first ammonium liquid 5648.36kg/h.NH
3/ CO
2(molecular ratio)=4.2, H
2O/CO
2(molecular ratio)=0.9, pressure P=20.5MPa in the tower, temperature t=188 ℃, CO
2Transformation efficiency 64.7%.
Enter CO after the decompression of urea synthesizer outlet melts
2Stripping tower is with P=4.0MPa, 99.5% CO
2Gas, tolerance are 835.28Nm
3/ h (wherein contains O
20.5%) carries out stripping.Pressure of stripping tower P=3.6MPa, temperature t=158 ℃, use steam heating, total ammonia steam rate 95.5%, first ammonium rate of decomposition 86.2% in the tower.
Contain urea 59.13%, NH in the urea liquid of stripping tower outlet at bottom
33.71%, CO
23.26%.Enter flash heater after the urine decompression.The flash heater steam heating, under pressure P=0.065MPa, temperature t=108 ℃ condition, total ammonia steam rate 99.61%, first ammonium rate of decomposition 98.58%.After the flash distillation outlet urine in urea concentration be 73%.
The NH that comes out in the stripping tower top
3, CO
2Enter Deng mixed gas among the pressure P=3.4MPa, tower on absorption tower, absorption tower and add the flash distillation phlegma, the weak ammonia that cat head adds liquefied ammonia and comes from the ammonia cleanser.73 ℃ of tower top temperatures, first ammonium liquid temp is t=120 ℃ at the bottom of the tower, absorbs the heat that produces and is removed by water coolant.Contain NH in the first ammonium liquid in the tower
339.37%, CO
244.31%, H
2O 16.32%, NH
3/ CO
2(molecular ratio)=2.3, H
2O/CO
2(molecular ratio)=0.9.
The part first ammonium liquid that comes out in absorption tower bottom is forced into 20MPa, adds 21Nm therein with high pressure carbamate pump
3/ h air, reheat to 185 ℃ enter urea synthesizer.
The absorption tower top exit contains and contains a large amount of NH in the ammonia gas
3, CO
2＜100ppm.With the gas ammonia condensation, liquefied ammonia passes back into the absorption tower through ammonia condenser in elder generation.Uncondensed gas enters the ammonia cleanser, with the soft water washing, with the phlegma washing that evaporation comes, makes 15.70% weak ammonia 35 ℃ of operations in pressure P=3.2MPa, temperature, passes back into the absorption tower, tail gas emptying compliance with environmental protection requirements.
73% urine of coming out from the flash separator bottom enters evaporation equipment, and the urine concentration behind two-stage evaporation reaches 99.5%, makes the granular urea product 2100kg/h of Φ 2～4mm with drum granulating.
Total ammonia utilization ratio of present embodiment is 97.26%.
Claims (2)
1, a kind of carbon dioxide stripping process urea production method comprises synthetic, stripping, absorption, flash distillation, evaporation, granulation, it is characterized in that:
(1) raw materials ammonia [31] and ammonium carbamate liquid [34], ammonium carbamate is called for short the first ammonium, enters urea synthesizer [1], reacts NH in urea synthesizer [1] under pressure 20～22MPa, 185～190 ℃ of conditions of temperature
3/ CO
2(molecular ratio)=4.5～5, H
2O/CO
2(molecular ratio)=0.9～1.2, the production intensity of tower is 8.4～10.5t/m
3D,
(2) urea melt after the building-up reactions [35] enters CO
2The top of stripping tower [2], CO
2Gas [32] is sent into the bottom of stripping tower [2], makes superfluous ammonia in the solution and first ammonium heating stripping when 155～160 ℃ of pressure 3.0～4.0MPa, temperature, and the peripheral flow rate in the tower is 500～750kg/mh,
(3) from CO
2Come out in stripping tower [2] top contains NH
3, CO
2, water vapor mixed gas [36] when carbamate condenser [17] and the first ammonium liquid [33] that come out in [4] bottom from the absorption tower mix and generate dense first ammonium liquid [34], do not absorb gas [53] from passing through absorption tower [4] down, pressure in the tower is 3.0～4.0MPa, column bottom temperature is that 110～120 ℃, tower top temperature are 70～80 ℃, superficial velocity in the tower is 0.02～0.03m/s, the NH of dense first ammonium liquid
3/ CO
2(molecular ratio)=2.4～2.6, H
2O/CO
2(molecular ratio)=0.9～1.2,
(4) from CO
2The urea liquid [41] that comes out in stripping tower [2] bottom enters flash heater [6] after reducing pressure by automatic decompression valve [25], and its pressure is 0.06～0.1MPa, and temperature is 100～110 ℃,
(5) liquid-vapor mixture [42] that comes out from flash heater [6] top NH through flash separator [7], the gas flash distillation phlegma [45] behind flash condenser [8]
3Be 16～18% (weight), CO
2Be 14～16% (weight),
(6) gas [37] of [4] top exit is first through the condensed liquefied ammonia of ammonia condenser [23] [31] feed liquor ammonia medial launder [3] from the absorption tower, gas reclaims remaining ammonia through ammonia cleaning tower [5] again, described pressure recovery is that 3.0～4.0MPa, temperature are 30～40 ℃, CO in the exit gas [40] after cleaning recovery
2＜100ppm, NH
3Be 2～4g/Nm
3, NH in the outlet ammoniacal liquor [39]
3Be that 10～15% (weight) and liquefied ammonia [31] reflux respectively and enters top, absorption tower [4] as absorption agent,
(7) urine concentration of urea liquid [43] behind evaporation equipment [11] that come out of flash separator [7] bottom is 99.5～99.8% (weight), delivers to granulating equipment [12] and make granular urea product [51].
2, according to the described carbon dioxide stripping process urea production of claim 1 method, it is characterized in that: evaporation condensate [47] Fen Erlu that described evaporation equipment [11] comes out advances ammonia still [9], be that 0.12～0.14MPa, cat head are 0.09～0.1MPa at the bottom of the ammonia still process pressure column, be that 105～110 ℃, cat head are 80～90 ℃ at the bottom of the ammonia still process temperature tower, charging is 90～100 ℃ in 35～45 ℃ of cat head chargings, the tower.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN96116210A CN1058704C (en) | 1996-01-11 | 1996-01-11 | Method for prepn. of urea by carbon dioxide stripping method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN96116210A CN1058704C (en) | 1996-01-11 | 1996-01-11 | Method for prepn. of urea by carbon dioxide stripping method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1154363A CN1154363A (en) | 1997-07-16 |
| CN1058704C true CN1058704C (en) | 2000-11-22 |
Family
ID=5123332
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN96116210A Expired - Fee Related CN1058704C (en) | 1996-01-11 | 1996-01-11 | Method for prepn. of urea by carbon dioxide stripping method |
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|---|---|
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100340320C (en) * | 2005-08-03 | 2007-10-03 | 四川泸天化股份有限公司 | Method for treating decomposed gas by low resistance vertical calandria type absorptive condenser |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101531919B (en) * | 2009-04-21 | 2012-12-12 | 天津大学 | Energy-saving device and operation process for absorption-stabilization system |
| CN103408466A (en) * | 2013-07-09 | 2013-11-27 | 内蒙古鄂尔多斯联合化工有限公司 | Equipment corrosion control method in producing urea by using CO2 stripping method |
| CN103408467B (en) * | 2013-08-08 | 2015-02-18 | 中国五环工程有限公司 | Low-energy-consumption urea production technology and system adopting CO2 stripping method |
| CN104591807A (en) * | 2014-12-22 | 2015-05-06 | 广西大学 | Preparation technology for extracting ammonia from urine to synthesize urea |
| CN110270122A (en) * | 2019-07-30 | 2019-09-24 | 河南心连心化学工业集团股份有限公司 | Ammonia stripping tower, method for removing gas ammonia and urea production device using ammonia stripping tower and method |
| CN115466200A (en) * | 2022-10-24 | 2022-12-13 | 上海超希实业有限公司 | High-quality synthetic urea processed by sectional control reaction and processing method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN87107627A (en) * | 1986-11-03 | 1988-07-27 | 斯塔米卡本公司 | Preparation method of urea |
-
1996
- 1996-01-11 CN CN96116210A patent/CN1058704C/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN87107627A (en) * | 1986-11-03 | 1988-07-27 | 斯塔米卡本公司 | Preparation method of urea |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100340320C (en) * | 2005-08-03 | 2007-10-03 | 四川泸天化股份有限公司 | Method for treating decomposed gas by low resistance vertical calandria type absorptive condenser |
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| Publication number | Publication date |
|---|---|
| CN1154363A (en) | 1997-07-16 |
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