CN1039413C - Stripping recirculation technology & apparatus for urea production - Google Patents
Stripping recirculation technology & apparatus for urea production Download PDFInfo
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Abstract
The present invention belongs to the field of urea production. The present invention provides a urea production technique and a device thereof for solving the problems of the existing urea technique by a gas stripping method of many high-pressure apparatus, large operation difficulty, unsafety, etc. The urea production technique uses binary preservative to satisfy apparatus preservation and safe operation. High-pressure tail gas with oxygen is introduced at the lower part of a medium-pressure decomposer for deactivating a medium-pressure system apparatus. Medium-pressure decomposition gas is condensed in an apparatus which uses a heat recovery section at the lower part of an evaporator as main. The urea production technique has the advantages of few high-pressure apparatus and reasonable structure, and is a new urea production technique with short process, low energy consumption, less investment, large operating flexibility, safety and reliability by the gas stripping method.
Description
The invention belongs to the urea production field.
As everyone knows, industrial with the existing in the world so far multiple production method of ammonia and carbon dioxide production urea, can be divided into two big classes usually: i.e. water solution total cycling method and vaporizing extract process.Water solution total cycling method is early stage process for producing urea, and its representative flow process has the water solution total cycling method of Si Tamikabang company; Recycle to extinction C method, the D method of Mitsui/eastern pressure company; The total recycle processes of Montecatini etc., this is high energy consumption one class methods.The vaporizing extract process urea production is the technology of the sixties and later development thereof, and its representative flow process has the CO2 vaporizing extract process (hereinafter to be referred as the CO2 vaporizing extract process) of Si Tamikabang company; The ammonia vaporizing extract process of SNAM S.P.A.; The isobaric double flow formulation (IDR method) of Montedisons SPA; The saving energy and cost novel process of Mitsui/eastern pressure company (being called for short the ACES method).They are to use CO2, NH3 or two kinds of process for producing urea that all use as steam stripping agent, have characteristic of low energy consumption.
In the CO2 of above-mentioned Si Tamikabang vaporizing extract process technology, the equipment in the high pressure circle synthesis includes: synthetic tower, and stripping tower, high pressure condenser, high pressure scrubber, they are all operated under same pressure, remove this and also have two steam pocketss.The synthetic tower working pressure is 13.7MPa (g), service temperature 183-185 ℃, and NH3/CO2 (mol)=2.8-2.9, H2O/CO2 (mol)=0.34, Synthesis conversion is 57%, stripping tower goes out 167 ℃ of liquid temps, contains NH37.8% in the solution, contains CO2 10%; Pay producing steam pressure 0.32-0.34MPa (g).
The CO2 stripping genealogy of law adopts low ammonia carbon ratio, low working pressure, and the technological operation that comes the reinforced high pressure circle promptly reaches the degree of depth stripping of stripping tower, the degree of depth absorption of high pressure scrubber, presses circulation section in cancelling with this, and the solution behind the stripping directly arrives low-pressure stage.The drawback of bringing like this is that equipment corrosion is big, and needing increases the passivation air capacity, causes tail gas to enter limits of explosion, and equipment need make explosion-proof type, increases the H2 system etc. of taking off.The short advantage of flow process has not just existed like this, and reduction of equipment effective rate of utilization and energy consumption are high relatively.Because the restriction of operational condition, the operating restraint of this method is very narrow, elasticity is little, and operational stability is poor, and device is difficult to realize long-term operation.The technology of making steam stripping agent with CO2 gas of age afterwards several new technological process (comprising stripping circulation method of the present invention) that grown up again for this reason.
In the saving energy and cost novel process (ACES method) of above-mentioned Mitsui/eastern pressure company, equipment in the high pressure circle synthesis has: urea synthesizer, CO2 stripping tower, first and second high pressure methylamine condenser, high pressure scrubber, they are all operated under same pressure, also have two steam pocketss in addition.The working pressure of urea synthesizer is: pressure 17.1MPa (g), and 190 ℃ of temperature, NH3/CO2 (mol)=4.0, H2O/CO2 (mol)=0.64, Synthesis conversion 68% is paid producing steam pressure 0.5MPa (g).This technology system adopts high ammonia carbon ratio, and high working pressure is to improve conversion rate of urea.But its high-tension apparatus platform number is many, and operation link is many, and operation easier is big, the individual device complex structure, and manufacture difficulty is big, and total cost of equipment increases.The protection against corrosion air capacity that this technology adds is big, and oxygen level is 0.5% of a raw material CO2 gas, and this has not only reduced the effective rate of utilization of equipment, and the hydrogen-oxygen ratio has reached limits of explosion in the intermediate pressure section tail gas, and the device operation is very dangerous.
The purpose of new stripping circulation method process for producing urea of the present invention and device thereof is intended to design a kind of energy-saving process for producing urea and device thereof with new characteristic, it is low that this method has energy consumption, and flow process is brief, and turndown ratio is big, the operational safety good reliability, advantages such as low equipment investment.
High pressure circle synthesis, middle pressure circulation section and the low-pressure recirculation section of including of the present invention is characterized in that with the stripping circulation method process for producing urea of CO2 as steam stripping agent:
(1). in the high pressure circle synthesis:
1.. the operating parameters of synthetic tower 4 is: pressure 15.5-16.5MPa (g), temperature 185-190 ℃, NH3/CO2 (molecular ratio) 3.5-3.7, H2O/CO2 (molecular ratio) 0.6-0.7, urea synthesis transformation efficiency 65-67%;
2.. the operating parameters of stripping tower 5 is: pressure 15.5-16.5MPa (g), go out 170-175 ℃ of tower solution temperature, go out tower solution ammonia content 11-13%;
3.. the operating parameters of high pressure methylamine condenser 6 is: pressure 15.5-16.5MPa (g), temperature 170-175 ℃, shell side byproduct steam pressure 0.4-0.6MPa (g);
4.. in high pressure loop, adopt the anticorrosion passivator of binary, promptly except that before CO2 gas advances compressor 1, adding the air, and add hydrogen peroxide (H2O2) in the ingress that the reactant of synthetic tower 4 flows into stripping tower 5, to satisfy the needs of the anticorrosion and safety operation of system device, service temperature height particularly, extent of corrosion are wanted the anticorrosion needs of big stripping tower relatively.The add-on of binary sanitas is: air 0.20-0.25% (in O2), hydrogen peroxide (H2O2) are 1.5-2.5Kg/T (urea); Hydrogen peroxide preferably adds system with the form of aqueous hydrogen peroxide solution;
(2). at middle pressure circulation section:
1.. be heated in M.P.decomposer 8 from the first ammonium in the solution of stripping tower 5 bottoms and be decomposed into CO2, NH3, required heat, epimere is supplied with by low-pressure steam, hypomere is supplied with by the middle pressure steam phlegma that stripping tower comes, the oxygen enrichment tail gas of introducing high pressure scrubber 7 in the bottom of M.P.decomposer 8 plays the stripping effect simultaneously with passivation medium voltage network equipment in the falling film type tubulation of M.P.decomposer; The operating parameters of M.P.decomposer 8 is: amount of pressure 1.6-1.8MPa (g), decomposition temperature 155-160 ℃;
2.. it is to carry out in one section vacuum-evaporator 22 bottom and middle pressure resorber 12 that the condensation of middle pressure decomposition gas absorbs, its heat of condensation is used for being concentrated into the urine of vacuum-evaporation operation, the middle heat of condensation of resorber 12 of pressing is removed with the temperature adjustment water coolant, the middle resorber 12 of pressing is that tower tray, hypomere are for forming on the absorption tower of filler by horizontal condenser and epimere, the absorption tower is adiabatic sorption section for upper and lower two sections, the ammonium bicarbonate solution that comes with dual circulation process condensate and low-pressure stage is made absorption agent respectively, and the temperature of middle pressure condenser system first ammonium liquid is 100-110 ℃;
(3). in low-pressure recirculation section:
Be recovered in the low pressure recovery system that low-pressure condenser 14, ammonium fluid storage tank 15, ammonium fluid pump 16, low pressure absorption tower 17, low pressure absorbent recirculation pump 18, low pressure absorb recirculation cooler 19 and the pipeline that is connected is formed from the gas of low pressure splitter 9 and desorption tower 32, the working pressure of this system is 0.1-0.3MPa (g).
A kind of urea technique will really can be realized industrialization, must reliable advanced person except technical process, rational device structure type selecting and good equipment and materials also to be arranged as assurance.In new stripping circulation method urea generation method of the present invention, the specific equipment that is adopted mainly contains stripping tower 5, hp ammonium carbamate condenser 6, M.P.decomposer 8, low pressure splitter 9 (basic identical with M.P.decomposer 8).The equipment that technology adopted such as all the other equipment and known CO2 vaporizing extract process, ACES method are similar basically.
Of the present inventionly include high pressure circle synthesis, middle pressure circulation section and low-pressure recirculation section and with the stripping circulation method urea plant of CO2 as steam stripping agent, wherein, the major equipment in the high pressure circle synthesis has synthetic tower, stripping tower, hp ammonium carbamate condenser, high pressure scrubber; The middle interior major equipment of circulation section of pressing has M.P.decomposer, middle pressure resorber; Major equipment in the low-pressure recirculation section has low pressure splitter, desorption tower, low-pressure condenser, low pressure absorption tower, it is characterized in that:
(1). stripping tower 5 is to set up a packing layer simple for production above the former tubulation liquid distribution head of general stripping tower, it is the filler distribution device, two portions are up and down arranged in the tower, and top is the filler distribution device and the tubulation liquid distributor of solution, and the bottom is the falling film type tube still heater.
The stripping tower of this kind structure, the packing layer on top can play the uniform distribution and the refinery distillation of material, and its setting can be played saving steam, improve the effect of steam stripping efficiency, are a kind of energy-saving CO2 stripping towers.See Fig. 2;
(2). hp ammonium carbamate condenser 6 adopts still formula U-shaped tube heat-exchanger, and tube side is a processing medium, shell side generation low-pressure steam, interchanger and steam inclusion and one.
This structure of hp ammonium carbamate condenser 6 not only makes technological operation simple, can also reduce by an independent steam pockets simultaneously, saves equipment manufacturing cost.See Fig. 3;
(3). M.P.decomposer 8 adopts and has the separator of packing layer and the structure that the falling film type tube still heater is combined, and top is rectifying section and tubulation liquid distributor, and the bottom is a falling film type tubulation heating zone, and this heating zone tube side is divided into upper and lower two sections again;
In to press resorber 12 be that tower tray, hypomere are that the absorption tower of filler is formed by horizontal condenser and epimere;
(4). the top of low pressure splitter 9 is packing section and tubulation liquid distributor, and the bottom is a falling film type tubulation heating zone.
The structure of the structure of low pressure splitter 9 and M.P.decomposer 8 is basic identical, and its difference only is falling film type tube still heater part, and low pressure heater 9 only is one section.
In this unitized construction, the low pressure splitter, have the function of pre-separation and pre-rectifying, the residence time is short, the thermo-efficiency height is paid reaction and is well controlled.See Fig. 4
New stripping circulation method process for producing urea of the present invention and device thereof are to optimize to transform on the basis of existing stripping circulation method process for producing urea and device thereof, and compared with prior art, the present invention has following advantage:
1. the ammonia carbon ratio that method high pressure loop of the present invention adopts is moderate, and processing condition relax, and the intermediate pressure section that is increased has been cancelled superfluous ammonia recovery system, and compared with big, the good stability of CO2 vaporizing extract process turndown ratio of Si Tamikabang, processing ease is grasped, the unit service factor height;
2. method of the present invention adopts the anticorrosion passivator of binary, and antiseptic property is good, has eradicated the combustion explosion source, device good operation safety, operation factor height;
3. middle pressure decomposition tower adopts falling film type tube still heater and the splitter group that has packing layer to lump together, function with pre-separation and pre-rectifying, and introduce the oxygen enrichment tail gas of high pressure section in its underpart, equipment that not only can the passivation medium voltage network, NH3 contained in the gas, CO2 are all reclaimed at intermediate pressure section, and play the stripping effect, thereby saved steam consumption;
4. method of the present invention adopts energy-saving CO2 stripping tower, promptly sets up a packing section simple for production on the top of general stripping tower, reaches gas, liquid is well distributed, promotes refinery distillation, greatly reduces the load of tubulation heating zone, thereby has saved steam;
5. the hp ammonium carbamate condenser of the inventive method adopts still formula U-shaped tube heat-exchanger, and shell is the generation low-pressure steam, and steam pockets and interchanger are one, independent steam pockets need not be established again,, liquid distributor etc. need not be established in the bobbin carriage compared with vertical tubulation carbamate condenser, designs simplification, the thermo-efficiency height;
6. handle the high pressure scrubber of synthetic tower gas phase, " ACES " method is a packing tower, and the CO2 vaporizing extract process is an immersion tubular heat exchange and with the bigger explosion-proof space of a volume, complex structure, and operation inconvenience, cost is higher.Technology of the present invention is established the sieve-tray tower of three tower trays in being, only plays adiabatic sorption, need not what control, and easy to operate and safe;
7. for the high pressure circle synthesis, " ACES " method is five high-tension apparatuses, and is with two low-pressure steam bags, and the CO2 vaporizing extract process is four high-tension apparatuses, is with two low-pressure steam bags, and new stripping circulation method process for producing urea of the present invention only is four high-tension apparatuses.On energy consumption, the steam consumption of technology of the present invention is close with " ACES " method, than the low about 250Kg/ ton (urea) of CO2 vaporizing extract process; From investment, the present invention is approaching with the CO2 vaporizing extract process that has increased dehydrogenation system, than " ACES " method low about 10%;
8. the armamentarium of the inventive method can be based on domestic manufacturing, thereby can save a large amount of foreign exchanges for country, and reduces investment outlay.
：1： ：1. 2. 3. 4. 5. 6.7. 8. 9.10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29.30. 31. 32. 33. 34. 35. MS CW PIC ( ) LS TW PRC ( ) SC HC LIC ( ) 2：
Wherein: 1. the synthetic liquid of tubulation liquid distributor 2. fillers 3. 4. pneumatic outlets that enter the mouth
6. urea solns go out 7. steam-ins, 8. condensate outlets 9,10. manhole Fig. 3 5.CO2 gas enters the mouth: the hp ammonium carbamate condenser structural representation
Wherein: 1. restrain 2. bobbin carriages, 3. gas inletes, 4. gas liquid outlets, 5. vapour outlets
6. the cold liquid of relief valve connection 7. steam inlet 8. steam-in 9. manhole Fig. 4 that go into operation: M.P.decomposer structural representation
Wherein: 1. filler 2. tubulation liquid distributors 3. tubulations 4. pump liquid 5. pneumatic outlets that enter the mouth
6. oxygen enrichment gas inlet 7. urines go out 8. low-pressure steam, 9. condensate outlets that enter the mouth
10. press cold liquid outlet in the cold liquid inlet 11. of middle pressure
Drawing explanation: method of the present invention and device thereof are described in further detail below in conjunction with new stripping circulation method urea production process schema of the present invention.
Fig. 1 is seen in the technical process of new stripping circulation method process for producing urea of the present invention: the compressed machine 1 of CO2 gas is gone into the bottom of stripping tower 5, for protection against corrosion, adds the air of 0.20-0.25% (in O2) in the inlet CO2 of compressor gas.Liquid NH3 is through high-pressure ammonia pump 2, and liquefied ammonia preheater 3 is gone into the bottom of synthetic tower 4, and reaction mixture is separated into gas phase and liquid phase at cat head.Liquid phase mixture is gone into stripping tower 5 tops, add the aqueous solution of hydrogen peroxide (H2O2) at this, to strengthen the anticorrosion of stripping tower, in stripping tower, solution is gone into the falling film type tube still heater through filler distribution device and tubulation liquid distributor, shell is with the heating of 2.2MPa (g) saturation steam, first ammonium in the solution and superfluous ammonia are decomposed under the stripping effect of heating and counter current contact CO2 gas and separate, the gas that goes out the stripping tower top is gone into hp ammonium carbamate condenser 6, mix with the first ammonium liquid of high pressure scrubber 7 and partial condensation at this gas, heat of condensation is used for paying the steam that produces 0.4-0.6MPa (g), and the gas-liquid mixture that goes out carbamate condenser is gone into the bottom of synthetic tower 4.In synthetic tower, material is through certain residence time, and CO2 wherein and NH3 continue reaction production first ammonium, and reaction heat is used to improve the interior temperature of charge of tower and provides the first ammonium to change into the heat of urea.The gas phase that goes out the synthetic tower top is gone into high pressure scrubber 7, and the first ammonium amine liquid of being sent here by first ammonium pump 13 at this portion C O2 and NH3 carries out thermal insulation and absorbs, and the liquid after the absorption is gone into hp ammonium carbamate condenser 6, and the tail gas that discharge at the top is gone into the bottom of M.P.decomposer 8.
The solution that goes out stripping tower 5 is gone into the space on M.P.decomposer 8 tops through decompression, passed through the top packing layer of distribution and refinery distillation then, go into the falling film type tube still heater of bottom again through the uniformly distributing of tubulation distribution head, first ammonium in the solution is heated at this and is decomposed into CO2, NH3, needed heat is supplied with by low-pressure steam at the well heater epimere, steams phlegma at hypomere by the middle pressure of stripping tower 5 and supplies with.Introduce oxygen enrichment tail gas from high pressure scrubber 7 in the bottom of M.P.decomposer 8 with passivation medium voltage network equipment, in the falling film type tubulation of splitter, play the stripping effect simultaneously.
The working pressure of M.P.decomposer 8 is 1.6-1.8MPa (g), and decomposition temperature is 155-160 ℃.
The solution that goes out M.P.decomposer 8 bottoms is gone into low pressure splitter 9 through regulator of level, and the structure of low pressure splitter 9 also is the structure that falling film type tube still heater and splitter group lump together with M.P.decomposer 8.In low pressure splitter 9, first ammonium remaining in the solution further resolves into CO2, NH3, decomposes required heat and is supplied with by low-pressure steam.The working pressure of low pressure splitter 9 is 0.15-0.30MPa (g), and decomposition temperature is 135-140 ℃.
The urine that goes out low pressure splitter 9 is gone into flash drum 10 through regulator of level, and its working pressure is 0.044MPa, and urine is gone into one section vacuum-evaporator 22 or urine groove 20 then.
The gas that goes out M.P.decomposer 8 napexes is gone into the hypomere of one section vacuum-evaporator 22 with the first ammonium liquid of middle pressure resorber 12, part CO2, NH3 condensation in this gas, heat of condensation is used for concentrating urea solution, go out the gas-liquid mixture that one section vacuum-evaporator, 22 hypomere shells are and go into first ammonium separator 11, first ammonium liquid is gone into high pressure scrubber 7 through high pressure carbamate pump 13, press resorber 12 to continue condensation during gas is gone into, heat of condensation is removed by temperature adjustment water.In horizontal, press condenser top to be provided with the absorption tower, this tower top is the column plate section, and the bottom is a packing section, and the column plate section is an absorption agent with the phlegma of dual circulation condensate pump 36, packing section absorbs with the solution spraying of ammonium fluid pump 16, and non-condensable gases enters atmosphere through pressure regulator valve.
Go out gas condensation in low-pressure condenser 14 of the gas and the desorption tower 32 of low pressure splitter 9, heat of condensation is removed with water coolant, gas-liquid mixture is gone into ammonium fluid storage tank 15 after the condensation, solution is pressed the packing section on resorber 12 absorption towers in ammonium fluid pump 16 parts are sent, part is as the phegma of desorption tower 32.Gas presses the phlegma of next solution of resorber 12 column plate sections and dual circulation condensate pump 36 to absorb to low pressure absorption tower 17 in the quilt.The noncondensable gas that goes out low pressure absorption tower 17 enters atmosphere through pressure regulator valve.
The technological process that the simmer down to of urine is traditional.Urine from flash drum 10 is concentrated into 99.7% through 22, two sections vacuum-evaporators 23 of one section vacuum-evaporator, through melt urea pump 24, and prilling spry 25, prilling tower 26 obtains the granular urea product.One section evaporation operation pressure is 0.027-0.033MPa (absolute pressure), and service temperature is 128-130 ℃, and the dual circulation working pressure is 0.0033MPa (absolute pressure), and service temperature is 138-140 ℃.From flash drum, one section vacuum-evaporator and two sections gas condensations in vacuum generating system 28 that vacuum-evaporator comes, vacuum generating system 28 is made up of surface condenser and steam injector, and heat of condensation is removed by water coolant, and lime set is gone into process condensate storage tank 29.
Process condensate from storage tank 29 contains small amount of N H3, CO2 and urea, and through desorption tower feeding pump 30, desorption tower preheater 31 is introduced desorption tower 32.Desorption tower 32 is formed by upper and lower two sections, solution is by the epimere column plate, wherein NH3, CO2 are come out by stripping, solution after the desorb is through hydrolyzer feeding pump 33, hydrolyzer preheater 34 is gone into hydrolyzer 35, urea in this solution under high temperature action and certain residence time be hydrolyzed into NH3 and CO2, needed heat is provided by middle pressure steam.The solution that goes out hydrolyzer 35 is gone into the top of desorption tower 32 hypomere column plates after heat exchange, solution stream wherein NH3, CO2 when each column plate come out by the steam stripped that the bottom adds.The liquid of deriving from desorption tower 32 bottoms is almost pure water, and ammonia and urea content are discharged the battery limit (BL) and utilized less than 5ppm after heat exchange.The gas that desorption tower 32 tops and hydrolyzer 35 are derived is gone into low-pressure condenser 14.The working pressure of hydrolyzer 35 is 2.3MPa (g), and the working pressure of desorption tower 32 is 0.3MPa (g).
The present invention is applied to vaporizing extract process urea production field.
Claims (2)
- One kind include high pressure circle synthesis, middle pressure circulation section and low-pressure recirculation section with the stripping circulation method process for producing urea of CO2 as steam stripping agent, it is characterized in that,(1). in the high pressure circle synthesis:1.. the operating parameters of synthetic tower (4) is: pressure 15.5-16.5MPa (g), temperature 185-190 ℃, NH3/CO2 (molecular ratio) 3.5-3.7, H2O/CO2 (molecular ratio) 0.6-0.7, urea synthesis transformation efficiency 65-67%;2.. the operating parameters of stripping tower (5) is: pressure 15.5-16.5MPa (g), go out 170-175 ℃ of tower solution temperature, go out tower solution ammonia content 11-13%;3.. the operating parameters of hp ammonium carbamate condenser (6) is: pressure 15.5-16.5MPa (g), temperature 170-175 ℃, shell side byproduct steam, its pressure are 0.4-0.6MPa (g);4.. in high pressure loop, adopt the anticorrosion passivator of binary, promptly add the air before except that advance compressor (1) at CO2 gas, and add hydrogen peroxide (H2O2) in the ingress that the reactant of synthetic tower (4) flows into stripping tower (5), the add-on of binary sanitas is: air 0.20-0.25% (in O2), hydrogen peroxide (H2O2) is 1.5-2.5Kg (H2O2)/T (urea), and hydrogen peroxide adds system in the mode of the aqueous solution;(2). at middle pressure circulation section:1.. be heated in M.P.decomposer (8) from the first ammonium in the solution of stripping tower (5) bottom and be decomposed into CO2, NH3, required heat, epimere is supplied with by low-pressure steam, hypomere is supplied with by the middle pressure steam phlegma that stripping tower comes, introduce the next oxygen enrichment tail gas of high pressure scrubber (7) with passivation medium voltage network equipment in the bottom of M.P.decomposer (8), simultaneously in the falling film type tubulation of M.P.decomposer, play the stripping effect, the operating parameters of M.P.decomposer (8) is: pressure 1.6-1.8MPa (g), decomposition temperature 155-160 ℃;2.. it is to carry out in one section vacuum-evaporator (22) bottom and middle pressure resorber (12) that the condensation of middle pressure decomposition gas absorbs, its heat of condensation is used for being concentrated into the urine of vacuum-evaporation operation, the middle heat of condensation of resorber (12) of pressing is removed with the temperature adjustment water coolant, and the temperature of first ammonium phlegma is 100-110 ℃;(3). in low-pressure recirculation section:Be recovered in the low pressure recovery system that low-pressure condenser (14), ammonium fluid storage tank (15), ammonium fluid pump (16), low pressure absorption tower (17), low pressure absorbent recirculation pump (18), low pressure absorb recirculation cooler (19) and the pipeline that is connected is formed from gas that low pressure splitter (9) and desorption tower (32) come, the working pressure of this system is 0.1-0.3MPa (g).
- By claim 1 described a kind of include high pressure circle synthesis, middle pressure circulation section and low-pressure recirculation section with the stripping circulation method urea plant of CO2 as steam stripping agent, wherein, the major equipment in the high pressure circle synthesis has synthetic tower, stripping tower, hp ammonium carbamate condenser, high pressure scrubber; The middle interior major equipment of circulation section of pressing has M.P.decomposer, middle pressure resorber; Major equipment in the low-pressure recirculation section has low pressure splitter, desorption tower, low-pressure condenser, low pressure absorption tower, it is characterized in that,(1). described stripping tower (5) is to set up a filler distribution device simple for production on the top of general stripping tower, and upper and lower two portions are arranged in the tower, and top is the filler distribution device and the tubulation liquid distributor of solution, and the bottom is the falling film type tube still heater;(2). described hp ammonium carbamate condenser (6), adopt still formula U-shaped tube heat-exchanger, tube side is a processing medium, shell side generation low-pressure steam, interchanger and steam inclusion and one;(3). described M.P.decomposer (8) adopts and has the separator of packing layer and the structure that the falling film type tube still heater is combined, its top is the rectifying separation section of filler and tubulation liquid distributor, the bottom is a falling film type tubulation heating zone, and this lower heating section is divided into upper and lower two sections again;(4). described low pressure splitter (9) top is packing section and tubulation liquid distributor, and the bottom is a falling film type tubulation heating zone.
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| CN93117513A CN1039413C (en) | 1993-09-16 | 1993-09-16 | Stripping recirculation technology & apparatus for urea production |
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| CN93117513A CN1039413C (en) | 1993-09-16 | 1993-09-16 | Stripping recirculation technology & apparatus for urea production |
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| CN87107799A (en) * | 1986-10-30 | 1988-07-06 | 东洋工程技术株式会社 | Process for separating unconverted raw materials |
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1993
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN87107799A (en) * | 1986-10-30 | 1988-07-06 | 东洋工程技术株式会社 | Process for separating unconverted raw materials |
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| CN1100412A (en) | 1995-03-22 |
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