Method of producing carbamide

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing carbamide from ammonia and carbon dioxide. The method is carried out at high temperature and pressure, molar ratio NH3:CO2=(3.4-3.7):1, in a carbamide synthesis reactor followed by extraction of excess ammonia from the carbamide synthesis fusion cake by separation at pressure 80-120 kgf/cm2, two-step distillation of the fusion cake, condensation of distillation gases with formation of recycled solutions of ammonium carbonates. First-step distillation is carried out at pressure 80-120 kgf/cm2 in a CO2 current. After distillation, the fusion cake is fed to the second distillation step which is carried out at low pressure. Distillation gases from the first step are condensed in two successive zones at distillation pressure of the first step, where in the first zone, condensation is carried out while feeding a portion of ammonium carbonate solution obtained during condensation of distillation gases at the second step. The condensed vapour is cooled with a condensate which boils at excess pressure to obtain vapour. The ammonium carbonate solution from the second condensation step is fed into the reactor. At the first distillation step, CO2 is used in amount of 30-35% of its total amount fed into the process. Gases and the liquid carbamide synthesis fusion cake are output from the carbamide synthesis reactor separately. Gases from the synthesis reactor and excess ammonia from the separation step are fed into the first condensation zone of distillation gases from the first step. In the second condensation zone of distillation gases from the first step, the condensed vapour is cooled by recycled water and uncondensed gases at the same pressure are washed by the other portion of the ammonium carbonate solution obtained during condensation of distillation gases from the second step, and the formed ammonium carbonate solution is fed into the second condensation zone.

EFFECT: process of producing carbamide with low power consumption.

1 dwg, 1 tbl, 3 ex

 

The invention relates to a process for the production of urea from ammonia and carbon dioxide.

A known method of producing urea, including the interaction of ammonia and carbon dioxide in the synthesis reactor at elevated temperature (160-190C) and pressure (125-200 kgf/cm2), a molar ratio of NH3:CO2=(1.5-to 3.5):1 (preferably 2,1:1) forming a reaction mixture containing urea, ammonium carbamate (hereinafter referred to carbamate and free ammonia in aqueous solution, separation output gases and liquid water synthesis of urea from the synthesis reactor, the subsequent filing of AA synthesis of urea stripper partial decomposition of carbamate and partial allocation of free ammonia in the current source of carbon dioxide (preferably 25-75% of its total amount introduced into the process at a pressure of 10 kgf/cm2to the pressure in the synthesis reactor, to obtain a gas stream comprising ammonia and carbon dioxide, and a liquid flow comprising urea and residual carbamate in aqueous solution, the feed liquid stream from the stripper on stage subsequent decomposition of the carbamate, the separation of ammonia and carbon dioxide and excretion of urea, the feed gas stream from the stripper on stage partial absorption-condensation, the flow generated at this stage of the liquid flow in the synthesis reactor (SU 190290 C07C 127/04, reissue of 1974).

As a result of using this method is a slight excess of ammonia conversion rate of carbon dioxide in the urea and the specific productivity of the reactor is low, resulting in significant capital cost of construction and to the large-scale recycling, require a high energy level 0,217 tons of equivalent fuel (here) on the production of 1 ton of urea.

The closest to the invention is a method of obtaining urea from ammonia and carbon dioxide at elevated temperature and pressure, the molar ratio of NH3:CO2=(3.6V-6.0V):1, in the reactor for the synthesis of urea with the subsequent release of excess ammonia from Plava synthesis of urea separation at a pressure of 60 to 120 kgf/cm2, a two-stage distillation of the solvent, the condensation of the gases of distillation with the formation of recycled solutions UAS, and the first distillation stage is carried out at a pressure of 60 to 120 kgf/cm2in the current CO2(~70% of the total quantity that you enter in the process), the water after distillation is passed to the second stage of distillation, which is carried out at low pressure, the gases of distillation first stage condense in two successive zones at a pressure of the first distillation stage, and in both zones condensable vapors are cooled condensation, boiling under OFL the exact pressure, steam used in subsequent stages of the process; in this case, the condensation in the first zone is carried out with excess CO2in the gas phase and the introduction of a solution of UAS obtained when the absorption-condensation of the gases of distillation of the second stage, the second condensation zone serves the separated ammonia solution UAS, leaving the second zone of condensation, is sent to the reactor, mixing before recirculation of liquid ammonia, and nscontainerframe gases are subjected to water absorption-condensation together with the gases of the second distillation stage (SU 692257, C07C 126/02, 1984).

This known method due to the combination of high molar ratio of NH3:CO2at the stage of synthesis with the holding of the first distillation stage at a pressure not as low as 10 kgf/cm2but not as high as the pressure of the synthesis, allows to minimize the cost of energy resources. As indicated in the description of this method, its implementation, the total specific energy consumption for production of 1 ton of urea are 0,166 here and much lower cost by other known methods. However, provided in a known manner the conditions of the condensation of gases from the distillation of the first degree in two successive zones provide a relatively low completeness of their condensation at a pressure of 60 to 120 kgf/cm2as the process of condensation at constant temperature and increasing the concentration of the ammonium carbamate formed in the solution UAS increases the equilibrium vapor pressure above the solution. Therefore, in the second condensation zone, cooled the same way as the first, condensation, boiling under pressure, the degree of condensation is low. Nscontainerframe at this stage, the gases are subjected to condensation in the low pressure stage. Thus, according to the example from the description of this known method, the total quantity of gas allocated at a pressure of 90 kg/cm2is 107900 kg/h, and of this amount, a step of low pressure passed 34900 kg/h (32%). This leads to the production of large quantities of dilute solution of UAS that before recycling it is necessary to concentrate, which requires additional energy costs. For this reason, the technical potential of the above combinations of conditions of synthesis and distillation of the first stage is not fully used.

The technical problem on which the invention is directed, is to create a process of obtaining urea with reduced energy costs.

To solve this problem, a method for obtaining urea from ammonia and carbon dioxide at elevated temperature and pressure, the molar ratio of NH3:CO2=(3,4-3,7):1 in the reactor for the synthesis of urea with the subsequent release of excess ammonia from Plava synthesis of urea separation at a pressure of 80-120 kg/cm2, a two-stage distillation of the solvent, the condensation of the gas is in distillation with the formation of recycled solutions of ammonium salts, moreover, the first distillation stage is carried out at a pressure of 80-120 kg/cm2in the current CO2the water after distillation is passed to the second stage of distillation, which is carried out at low pressure, the gases of distillation first stage condense in two successive zones at a pressure of the first distillation stage, while in the first zone, the condensation is carried out at the introduction part of the solution ammonium salts obtained by condensation of the gases of the second distillation stage, and condensable vapors are cooled condensation, boiling under pressure, steam, solution ammonium salts, leaving the second zone of condensation, is directed into the reactor, characterized in that the first stage of distillation CO2use in quantity 30-35% of its total amount introduced into the process from the synthesis reactor urea separately remove gases and liquid water synthesis of urea, the gases withdrawn from the synthesis reactor, together with excess ammonia allocated for phase separation, is introduced into the first zone of condensation of gases from the distillation of the first stage, in the second zone to the condensation of gases from the distillation of the first stage of condensable vapors are cooled by the circulating water, and nscontainerframe gases at the same pressure washed with another portion of the solution of ammonium salt, obtained by condensation of the gas is the second distillation stage, and the resulting solution of ammonium salts is injected into the second condensation zone.

The technical result arising from the use of the proposed method lies in the fact that, thanks to the introduction of gaseous flows from the synthesis reactor and from the zone of separation of excess ammonia in the first condensation zone at a pressure of 80-120 kg/cm2together with the gases of distillation of the first stage, it is possible to significantly increase the degree of condensation of ammonia and carbon dioxide at this stage and accordingly increase the production of steam by condensation, and reduce the amount of gases that must be condensing at low pressure. This fact entails a reduction of energy costs in the production of urea to 0,160 here for 1 ton of urea.

The invention is illustrated by the following examples with reference to the process flow shown on the attached figure 1.

EXAMPLE 1. In the synthesis reactor urea 1 serves the flow of liquid ammonia 2 (47147 kg/h) and gaseous carbon dioxide 3 (39536 kg/h)and recirculated solution of UAS 4 (142096 kg/h; ammonia 53,8, carbon dioxide 34,2, water 10,5, urea 1,6) from the second condenser high pressure 5 (molar ratio of NH3:CO2in the reactor 3,63:1). In the reactor at a pressure of 200 kgf/cm2and a temperature of 190C are formed, and p is zdolno derived from stream 6 Plava synthesis of urea: (217340 kg/h; urea 39,4, ammonia 29,9, carbon dioxide 12,4, water 18,4; hereinafter, all compositions are given in wt.%; the content of ammonium carbamate is shown as ammonia and carbon dioxide, a product of the interaction of which he is; the content of inert impurities in the gas streams not shown) and flow 7 nscontainerbox gases (ammonia 11439 kg/h). Thread 6 drossellied to a pressure of 90 kg/cm2in the separator 8, where the at 165C is allocated gaseous stream 9 (22268 kg/h; ammonia 76,5, carbon dioxide 19,4, water 4,1). Thread 10 of the water from the separator 8 (195072 kg/h; urea 43,9, ammonia 24,5, carbon dioxide 11,6, water 20,0; the molar ratio of NH3:CO2=2,18 - based urea) without changing the pressure supplied to the stripper 11, where when heated vapor pressure (49459 kg/h, pressure of 18.5 kgf/cm2and blowing carbon dioxide (flow 12; 21389 kg/h) at 170C in the lower part of the decomposition of the larger part of the ammonium carbamate and the distillation of the excess ammonia. The water is withdrawn from stripper 11 (stream 13; 140240 kg/h; urea 60,6, ammonia 7,8, carbon dioxide 7,0, water 24,7), is subjected to further processing using conventional manufacturing methods: second distillation stage at a pressure of 3 kgf/cm2and a temperature of 135-140C, the condensation of the selected gas in the cooling water with the formation of a dilute solution of UAS, liparian the e solution of urea in three stages under vacuum (residual pressure of 50, 30 and 3 kPa) to a concentration of 98.5-99.5% of the subsequent pillromanian or granulation, which receive 84000 kg/h of urea. The gas flow 14 from the stripper 11 (76221 kg/h; ammonia 48,5, carbon dioxide 45,0, water 5,7, urea 0,9) together with the threads 7 and 9 enters the first condenser high pressure 15. In the condenser 15 serves also part of the solution UAS obtained by condensation of the gases of the second distillation stage (stream 16; 15891 kg/h; ammonia 35,6, carbon dioxide 30,3, water 29,3, urea 4,8). In the annular space of the condenser 15 by evaporation of the steam condensate from the tank 17, due to the heat of formation of carbamate and dissolution of ammonia at 157C To form 55647 kg/h steam pressure of 3 kgf/cm2(stream 18), which is used in subsequent stages of the process. Gas-liquid mixture from the condenser 15 is supplied to the second condenser high pressure 5, which also serves the solution UAS from the absorber to the high pressure 19 (thread 20; 24320 kg/h; ammonia 55,0, carbon dioxide 21,2, water 20,5, urea 3,4). In the condenser 5 at 115C (cooling circulating water) condenses a large part of the gases not condensed in the condenser 15, with the formation of recirculated into the reactor 1 stream 4. A large part of the gases not condensed in the condenser 5 (thread 21; ammonia 8044 kg/h), is absorbed by another part of the solution UAS received at stake is Ansatie gases of the second distillation stage (stream 22; 17000 kg/h; composition identical to the composition of the stream 16), in the absorber high pressure 19 stream 20 solution of UAS. Unabsorbed ammonia (1990 kg/h) in a mixture with inert gases (stream 23; less than 2% of the total amount of gases, condensed at a pressure of 90 kg/cm2threads 7, 9 and 14) is sent for final absorption in the absorber low pressure 24. The number and compositions of the streams are also given in the accompanying table.

EXAMPLE 2. Differs from example 1 in that the separator 8, the stripper 11, the capacitors 15 and 5 and the absorber 19 operate at a pressure of 80 kgf/cm2. The temperature in the reactor 1, the separator 8, the lower part of the stripper 11, the capacitors 15 and 5, respectively 190, 162, 170, 152 and 110C. the vapor Pressure generated in the capacitor 15 is 2.8 kgf/cm2. The number and compositions of the streams are given in the table.

EXAMPLE 3. Differs from example 1 in that the separator 8, the stripper 11, the capacitors 15 and 5 and the absorber 19 operate at a pressure of 120 kgf/cm2. The temperature in the reactor 1, the separator 8, the lower part of the stripper 11, the capacitors 15 and 5, respectively 195, 175, 170, 166 and 150C. the vapor Pressure generated in the capacitor 15, is 3.2 kgf/cm2. The number and compositions of the streams are given in the table.

Table
The number and composition of flows examples
# threadQuantity, kg/hComposition, wt.%
NH3CO2ureawater
Example 1
247147100
339536100
414209653,834,21,610,5
621734029.912, 39,418,4
711439100
92226876,519,44,1
1019507224,5the 11.643,920,0
1221389100
131402407,87,060,624,7
14 7622148,545,00,9the 5.7
161589135,630,34,829,3
1855647100
202432055,0of 21.23,4a 21.5
218044100
221700035,630,34,8 29,3
231990100
Example 2
247150100
339536100
414252753,834,21,610,5
621775229,912,539,318,3
711461 100
92432776,519,8the 3.8
1019342624,0the 11.644,320,2
1221389100
131398197,66,960,724,8
147499547,945,50,95,8
161553335,330,2a 4.929,7
1857671100
202497255,920,63,320,2
218761100
221699535,330,2a 4.929,7
232761100
Example 3
247152100
339536100
414112753,734,11,610,6
621642529,712,339,518,5
711391100
974,320,55,2
1019880525,811,5to 43.119,6
1221389100
131411668,37,060,224,6
147902950,143,60,85,5
161687637,029,8the 4.7 28,6
1851866100
202496057,120,33,219,4
218747100
221697537,029,8the 4.728,6
232466100

A method of producing urea from ammonia and carbon dioxide at elevated temperature and pressure, the molar ratio of NH3 :CO2=(3,4-3,7):1, in the reactor for the synthesis of urea with the subsequent release of excess ammonia from Plava synthesis of urea separation at a pressure of 80-120 kg/cm2, a two-stage distillation of the solvent, the condensation of the gases of distillation with the formation of recycled solutions of ammonium salts, and the first distillation stage is carried out at a pressure of 80-120 kg/cm2in the current CO2the water after distillation is passed to the second stage of distillation, which is carried out at low pressure, the gases of distillation first stage condense in two successive zones at a pressure of the first distillation stage, while in the first zone, the condensation is carried out at the introduction part of the solution ammonium salts obtained by condensation of the gases of the second distillation stage, and condensable vapors are cooled condensation, boiling under pressure, steam, solution ammonium salts, leaving the second zone of condensation, is directed into the reactor, characterized in that the first stage of distillation CO2use in quantity 30-35% of its total amount introduced into the process from the synthesis reactor urea separately remove gases and liquid water synthesis of urea, the gases withdrawn from the synthesis reactor, together with excess ammonia allocated for phase separation, is introduced into the first AOR is the condensation of the gases of the first distillation stage, in the second zone to the condensation of gases from the distillation of the first stage of condensable vapors are cooled by the circulating water, and not condensed gases at the same pressure washed with another portion of the solution of ammonium salt, obtained by condensation of the gases of distillation of the second stage, and the resulting solution of ammonium salts is injected into the second condensation zone.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing urea from ammonia and carbon dioxide. The method comprises the following steps: feeding ammonia and carbon dioxide into a urea synthesis section operating at given high pressure; reaction of ammonia and carbon dioxide in the synthesis section to obtain an aqueous solution containing urea, ammonium carbamate and ammonia; feeding a first portion of said aqueous solution containing urea, ammonium carbamate and ammonia into a processing section operating at given medium pressure to extract ammonium carbamate and ammonia contained in that solution; dissociation of the first portion of said aqueous solution containing urea, ammonium carbamate and ammonia in the processing section to obtain an aqueous solution of urea and a vapour phase containing ammonia, carbon dioxide and water; condensation of said vapour phase containing ammonia, carbon dioxide and water in the processing section to obtain aqueous ammonium carbamate solution; directing the aqueous ammonium carbamate solution to the repeated cycle in the urea synthesis section. The method also involves feeding aqueous solution of urea obtained at the dissociation step in the processing section into a decomposition apparatus located in the urea extraction section and operating at given low pressure; decomposition of aqueous solution of urea in the decomposition apparatus in the urea extraction section to obtain concentrated urea solution and a second vapour phase containing ammonia, carbon dioxide and water; condensation of the second vapour phase in a condenser located in the urea extraction section and linked to said decomposition apparatus to obtain a first recycle aqueous solution of ammonium carbamate; steam stilling the second portion of aqueous solution containing urea, ammonium carbamate and ammonia while heating in a steam stilling unit essentially at the given high pressure to obtain a second aqueous solution of urea and a third vapour phase containing ammonia, carbon dioxide and water, where said heating is carried out via indirect heat exchange with a vapour stream which forms condensed vapour upon condensation; using at least a portion of the condensed vapour as heat carrier for dissociation of the first portion of the aqueous solution containing urea, ammonium carbonate and ammonia in the dissociation unit located in the processing section at medium pressure. The invention also discloses apparatus for producing urea and a method for upgrading existing apparatus for producing urea.

EFFECT: invention increases production capacity of apparatus for producing urea while simultaneously ensuring high degree of conversion of carbon dioxide to urea.

21 cl, 2 dwg

FIELD: chemistry.

SUBSTANCE: invention refers to the way of carbamide production at higher temperatures and under the pressure in the installation that contains a high pressure section including a reactor, stripper, condenser and gas washer. The method includes interaction between ammonia and carbon dioxide in the reactor with formation of the reactor feed and separate withdrawal of the liquid flow containing carbamide, ammonium carbamate and free ammonia in water solution from the reactor, and the gas flow containing predominantly inert gases. The flows of liquid and gas carbon dioxide are fed to the high pressure section. The liquid flow from the reactor is for to the stripper for partial decompounding of the ammonium cabamade and partial release of the free ammonia in the current of the gas carbon dioxide that is introduced into the stripper and includes ammonia and carbon dioxide admixed with water vapour, and of the liquid flow including carbamide and residual ammonium carbamade in the water and ammonia solution. The liquid flow from the stripper is fed at the stage of subsequent decompounding of the ammonium carbamade and separation of ammonia and carbon dioxide thus obtaining carbamide and recirculating liquid flow containing ammonium carbamade in the water and ammonia solution. The gas flow from the stripper is fed to the condenser for partial absorption and condensation in the course of mixing with ammonia and the liquid flow from the gas washer. The liquid flow from the condenser is fed to the reactor. The gas flow from the reactor is cleaned from ammonia and carbon dioxide while contacting with the recirculating liquid flow in the gas washer. The flow of liquid carbon dioxide is introduced into the reactor or condenser after it has been mixed with another process flow; the flow of liquid carbon dioxide is mixed with the liquid flow coming out from the gas washer or the condenser.

EFFECT: improvement of reliability of the applied equipment.

4 cl, 3 dwg, 3 ex

FIELD: chemistry.

SUBSTANCE: carbamide is obtained at high temperature and pressure in an apparatus having a high-pressure section, including a reactor, a stripper, a condenser and a scrubber, using a method which involves reaction of ammonia and carbon dioxide in the reactor to form a reaction mixture and separate outlet from the reactor of a liquid stream containing carbamide, ammonium carbamate and free ammonia in aqueous solution, and a gas stream mainly containing inert gases, feeding into the high-pressure section streams of liquid and gaseous carbon dioxide, feeding the liquid stream from the reactor into the stripper for partial decomposition of ammonium carbamate and partial extraction of free ammonia in the current of gaseous carbon dioxide fed into the stripper to obtain a gas stream containing ammonia and carbon dioxide with a water vapour impurity, and a liquid stream, feeding the liquid stream from the stripper to the next ammonium carbamate decomposition step and separating ammonia and carbon dioxide to obtain carbamide and a recycled liquid stream containing ammonium carbamate in an aqueous ammonium solution, feeding the gas stream from the stripper into the condenser for partial absorption-condensation thereof while mixing with ammonia and the liquid stream from the scrubber, feeding the liquid stream from the condenser into the reactor, removing ammonia and carbon dioxide from the gas stream from the reactor upon contact with the recycled liquid stream in the scrubber, where the stream of liquid carbon dioxide is fed into the high-pressure section after mixing with another process stream, where the stream of liquid carbon dioxide is mixed with a gas stream coming from the stripper or condenser, in the apparatus for mixing said streams, where when feeding the liquid stream into an insert with a variable cross-section through a convergent nozzle and the gas stream into the housing, liquid carbon dioxide evaporates through contact in the insert with part of said gas stream entering the insert, followed by contact of the mixed stream at the outlet of the insert with the remaining part of the gas stream passing through a slit between the insert and the housing.

EFFECT: high reliability of the used equipment.

4 cl, 3 ex, 4 dwg

FIELD: medicine, pharmaceutics.

SUBSTANCE: invention relates to method of obtaining carbamide with stable carbon isotope 13C for application in medical diagnostics of gastrointestinal tract diseases. Claimed method has two stages, the first stage includes interaction of labeled carbon dioxide and propylene oxide at temperature 120-130C and pressure 1.3-1.5 MPa in presence of catalyst with further isolation of labeled propylene carbonate. Catalyst of the first stage is complex of zinc bromide with tertiary organophosphine or 1-butyl-3-methylimidasolium chloride, and mole ratio of propylene oxide to catalyst constitutes 500-2000:1. At the second stage carried out is ammonolysis of isolated liquid propylene carbonate at temperature 130-150C and pressure 5.0-7.0 MPa with further isolation of target product.

EFFECT: method ensures obtaining carbamide, labeled by stable isotope 13C, with high output with sufficient simplicity and manufacturability of method and absence of highly toxic and explosive substances.

4 cl, 2 tbl, 14 ex

FIELD: agriculture.

SUBSTANCE: liquid ammonia and carbon dioxide are fed to a synthesis section (100) and exposed to a reaction in it in order to produce urea. At the same time the synthesis section comprises at least a reactor, a steaming device and a capacitor, which form a high-pressure circuit, and at least some carbon dioxide is sent to the synthesis section (100) in the liquid phase. Also a plant is proposed for production of urea, as well as a method to increase urea production plant efficiency.

EFFECT: increased energy efficiency of urea production method.

13 cl, 7 dwg

FIELD: process engineering.

SUBSTANCE: invention relates to plant intended for producing carbamide from ammonium and carbon dioxide at elevated temperature and pressure. Proposed plant comprises high-pressure section comprising reactor, stripper, condenser and scrubber operated at in face one pressure, liquid ammonium feeder, appliance to feed gaseous and liquid carbon dioxide into high-pressure section, appliances to feed liquid flows from reactor into stripper, from stripper at carbamide and circulated liquid flow extraction stage, from condenser into reactor, from scrubber into condenser, appliances to feed gas flows from reactor into scrubber, from stripper into condenser, appliances to feed circulated liquid flow into scrubber, appliance to mix liquid carbon dioxide with another flow including cylindrical housing with appliances to feed liquid carbon dioxide, another process flow and to discharge mixed flow, as well as tapered nozzle arranged inside said housing and aligned therewith and communicated with liquid carbon dioxide feed appliance. Note here that appliance to mix liquid carbon dioxide with gaseous carbon dioxide comprises gaseous carbon dioxide feed union and variable-section insert made up of tube with convergent inlet section and divergent outer. Note also that said insert is arranged to form annular clearance between housing and insert. Also it's proposed the method of carbamide production.

EFFECT: higher reliability.

2 cl, 2 ex, 2 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to apparatus for producing carbamide from carbon dioxide and liquid ammonia at high pressure and temperature, comprising a carbamide synthesis reactor, a pump for feeding liquid ammonia into the carbamide synthesis reactor, a compressor for feeding gaseous carbon dioxide into the carbamide synthesis reactor, a pump for feeding liquid carbon dioxide into the carbamide synthesis reactor, a device for bringing into contact carbon dioxide streams, characterised by that the device for bringing into contact carbon dioxide streams has a cylindrical housing with nozzles for inlet of liquid carbon dioxide, inlet of gaseous carbon dioxide and outlet of the mixed gaseous stream of carbon dioxide, as well as the following, arranged in series inside the housing and coaxial with the housing: a convergent nozzle connected to the liquid carbon dioxide inlet nozzle, and a variable cross-section insert in form of a pipe, the inlet part of which is convergent and the outlet part divergent, where the insert lies in such a way that an annular slit forms between itself and the housing. The invention also relates to a method of producing carbamide using the described device.

EFFECT: use of the present invention simplifies process design, reduces materials consumption of the equipment used and increases reliability of the equipment used.

2 cl, 3 ex, 2 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to a novel method of producing carbamide with a stable 13C isotope used in medical diagnostics, involving reaction of labelled carbon dioxide and ethylene oxide at temperature 80-150C, pressure 2.1-6 MPa in the presence of a catalyst - complex of zinc bromide and tertiary organophosphines in molar ratio of ethylene oxide to the catalyst equal to 500-5000:1, followed by extraction of the labelled ethylene carbonate and ammonolysis of the extracted ethylene carbonate at temperature 120-170C and pressure 2.8-4.7 MPa.

EFFECT: possibility of obtaining an end product with good output using a fairly simple and technologically effective method.

4 cl, 14 ex, 2 tbl

FIELD: chemistry.

SUBSTANCE: method of producing urea from ammonia and carbon dioxide involves the following steps: feeding ammonia and carbon dioxide into a urea synthesis section working at given high pressure, reaction of ammonia and carbon dioxide in the synthesis section to obtain aqueous solution containing urea, ammonium carbamate and ammonia, feeding a portion of the said aqueous solution containing urea, ammonium carbamate and ammonia into a processing section working at given average pressure for extraction of ammonium carbamate and ammonia contained therein, dissociation of the said portion of the aqueous solution containing urea, ammonium carbamate and ammonia in the processing section to obtain aqueous solution of urea and a vapour phase containing ammonia, carbon dioxide and water, condensation of said vapour phase containing ammonia, carbon dioxide and water in the processing section to obtain aqueous solution of ammonium carbamate, recirculation of said aqueous solution of ammonium carbamate into the urea synthesis section, feeding the remaining portion of the said aqueous solution containing urea, ammonium carbamate and ammonia into a decomposition apparatus in the urea extraction section through an evaporation zone, essentially working at said given high pressure, and characterised by that it also involves the following steps: feeding aqueous solution of urea obtained after dissociation in the processing section into the decomposition apparatus in the urea extraction section working at given low pressure, decomposition of the aqueous solution of urea in the decomposition apparatus of the urea extraction section to obtain concentrated urea solution and a second vapour phase containing ammonia, carbon dioxide and water, condensation of the second vapour phase in the condenser of the urea extraction section linked with said decomposition apparatus to obtain recycled aqueous solution of ammonium carbamate. The invention also relates to apparatus for realising said method and a method of renovating an already mounted installation.

EFFECT: high conversion of carbon dioxide to obtain urea with low power consumption.

12 cl, 1 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to basic organic synthesis and a method of producing ethylene glycol together with carbamide from carbon dioxide, ethylene oxide and ammonia. The method involves carrying out the process in two steps: first, reaction of carbon dioxide and ethylene oxide at temperature 80-150C, pressure 2.1-6 MPa in the presence of a homogeneous catalyst - complex of zinc bromide with tertiary organophosphines with subsequent extraction of ethylene carbonate, followed by ammonolysis of ethylene carbonate in a single process step in ether-type solvents which partially dissolve carbamide, at temperature 120-170C and pressure 2.8-6 MPa to obtain ethylene glycol and carbamide.

EFFECT: method enables virtually complete conversion of starting material to the end products, and also considerably lowers power consumption due to improvement of the process of separating ethylene glycol and carbamide.

3 cl, 2 tbl, 14 ex

FIELD: industrial inorganic synthesis.

SUBSTANCE: aqueous carbamate solution leaving urea recovery section at a certain temperature is decomposed by indirect heat exchange with flowing heat carrier having specified temperature. Temperature difference between aqueous carbamate solution and heat carrier is thus decreased to a value not exceeding 70°C, preferably to a value within a range of 20-40°C. Aqueous carbamate solution, prior to be fed into decomposition apparatus, is preheated in heat exchanger by stream produced in evaporation zone containing ammonia and carbon dioxide in vapor phase.

EFFECT: increased efficiency of apparatuses designed for decomposition of recycled carbamate solution.

6 cl, 2 dwg

FIELD: chemical technology.

SUBSTANCE: invention relates to producing urea from ammonia and carbon dioxide. Method involves preparing products of reaction in the synthesis zone as a solution containing urea, ammonium carbamate and unreacted ammonia. Part of solution obtained in synthesis of urea (preferably 10-60 wt.-%) is fed from the synthesis zone to additionally assembled zone of treatment under mean pressure at 1-4 MPa wherein gas flow is separated and subjected for absorption with ammonium carbamate solution of low pressure supplying from the section for isolation and treatment of urea. As a variant of method the invention proposes to use the combined reactor in the synthesis zone representing vertically installed or combined reactor. Enhancement of output of existing processes in synthesis of urea is achieved by feeding part of urea solution synthesized in the synthesis reactor to additionally installed zone for treatment of mean pressure including the dissociation zone, desorption zone of mean pressure and the condensation zone of mean pressure. Invention provides enhancement of output of unit for producing urea being without modification of section of high pressure.

EFFECT: improved method for producing urea.

10 cl, 4 dwg

FIELD: chemical technology.

SUBSTANCE: invention relates to technology for preparing urea. Method involves interaction of pure ammonia and carbon dioxide in reaction space to obtain reaction mixture containing urea, carbamate and free ammonia in an aqueous solution that is treated in evaporator (1) to obtain partially purified mixture that is fed to section for isolation of urea. Diluted solution of carbamate removing from the urea isolating section is subjected for treatment in evaporator (2) and at least part of vapors formed in it is recovered to the reaction space and/or into evaporator (1). Significant part of carbamate in aqueous solution is subjected for decomposition under pressure that corresponds essentially to pressure value in reaction space. Part of decomposition products including ammonia and carbon dioxide in vapor phase is recovered into reactor and/or into the first evaporator (1) and carbamate after its partial decomposing is fed into section for isolating urea. Device for preparing urea consists of the synthesis reactor, evaporators (1) and (2) for partial decomposition of carbamate and for separation of free ammonia and carbon dioxide in vapor phase, apparatus for condensation of vapor flow, pipe-line for recover of carbamate part in aqueous solution into reactor and section for isolation of urea from its aqueous solution. Preferably, pipe-line is fitted with ejector and evaporators are fitted with apparatus for feeding carbon dioxide as a evaporating agent. Invention provides enhancing yield of urea, reducing energy consumptions and investment due to updating the technological schedule of the process.

EFFECT: improved preparing and updating methods.

30 cl, 4 dwg

FIELD: chemical industry; devices and methods of production of carbamate.

SUBSTANCE: the invention is pertaining to the field of chemical industry, in particular, to carbamatecondenserof the sinking type used in the installation for production of the synthesized carbamide from the gaseous carbon dioxide and the liquid ammonia. The condenser (1) of the sinking type contains the bundle (5) of pipes, in which the condensation of the gaseous compounds is exercised and as a result of the interaction of ammonia with carbon dioxide the carbamate is formed. The condenser differs from others by availability the condensate circulating pipe (19, 23) structurally not connected with the bundle (5) of pipes and designed for circulation of the components in the closed contour of the condenser (1)of the part of the condensed inside it gaseous compounds. The availability of the separate circulating pipe structurally not connected with the bundle of the condensation pipes and communicating with the upper and the lower parts of the condenser ensures the possibility of circulation of the carbamate passing over of the bundle of the condensation pipes, what allows to increase essentially the output of carbamate gained as a result of condensation.

EFFECT: the invention allows to raise essentially the output of carbamate gained as a result of condensation.

6 cl, 3 dwg

FIELD: chemical industry; methods and the devices for production of carbamide from ammonia and carbon dioxide.

SUBSTANCE: the invention is pertaining to the field of chemical industry, in particular, to the methods and the devices for production of carbamide from ammonia and carbon dioxide. The method of production of carbamide includes the interaction of ammonia and carbon dioxide in the zone of synthesis at the heightened temperatures and pressures with formation of the melt of the carbamide containing carbamide, water, ammonium carbamate, ammonia and carbon dioxide. The carbamide melt distillation conduct at the heat feeding on the two stages of pressure preferentially at 15-25°C and 2-5 kgf/cm2. The carbamide melt distillation on the first step of the pressure conduct sequentially in two zones. In the first zone the distillation is conducted adiabatically or at the heat feeding, and in the second zone - at the heat feeding in the stream of carbon dioxide. The condensation-absorption process at refrigeration of the gases of the distillation is conducted with utilization of the aqueous absorbers. The formed aqueous solutions of the carbon- ammonium salts are recycled from the stage of the condensation-absorption of the gases of the distillation of the second step to the stage of the condensation-absorption of the gases of distillation of the first step, and also from the stage of the condensation-absorption of the gases of distillation of the first step into the zone of the synthesis. The evaporation of the aqueous solution of carbamide is exercised in some steps at the heat exchange between the gases of the distillation of the first step and the aqueous solution of carbamide at the stage of the preliminary evaporation. The installation for production of carbamide consists of: the reactor of the carbamide synthesis; the device with the heat feeding from the external source for distillation of the carbamide melt produced in the reactor of the carbamide synthesis at the first step of the pressure and consisting of the column of distillation melt of the first step and the film-type heat exchanger; the device with the heat feeding for the distillation of the carbamide melt on the second step of pressure; apparatuses for evaporation at heating of the aqueous solution of the carbamide produced on the second step of distillation. The devices for condensation-absorption at refrigeration of the gases of the distillation of the both steps switch on the heat exchanger-recuperator for heat interchange between the gases of the distillation of the first step and the aqueous solution of carbamide. The installation also contains a means for feeding of ammonia and carbon dioxide into the reactor of synthesis of carbamide, feeding of the carbamide melt from the reactor of synthesis into the column of distillation of the first step, from the column of distillation of the first step into the film-type heat exchanger and from the film-type heat exchanger into the device for distillation of the second step, the aqueous solution of carbamide from the device for distilling of the second step into the heat exchanger-recuperator and from the heat exchanger-recuperator - into the apparatus for the subsequent evaporation; the gases of distillation from the device for distilling of the first step - in the heat exchanger-recuperator and from the heat exchanger-recuperator - into the device for condensation-absorption of the gases of distillation of the first step; the gases of distillation from the apparatus for distillation of the second step - into the device for condensation-absorption of the gases of distillation of the second step; the solution of the carbon-ammonium salts from the device for condensation-absorption of the gases of distillation of the second step - into the device for condensation-absorption of the gases of distillation of the first step and from the device for condensation-absorption of the gases of distillation of the first step - into the reactor of synthesis, a means for feeding of carbon dioxide into the film-type heat exchanger. The technical result of the invention is the increased degree of the heat recuperation of the production cycle and reduction of he quantity of the heat exchangers using the heating steam from the external sources.

EFFECT: the invention ensures the increased degree of the heat recuperation of the production cycle and reduction of he quantity of the heat exchangers using the heating steam from the external sources.

8 cl, 3 ex, 3 dwg

FIELD: chemical industry; methods of synthesis of carbamide and the column for its realization.

SUBSTANCE: the invention is pertaining to the method of synthesis of carbamide from ammonia and carbon dioxide in the column of synthesis with the gas-liquid recycle, at which the stream of the water solution of the carbon-ammonium salts (CAS) from the area of distilling route from above or from below into the middle of the synthesis column containing the vertical cylindrical body, the corrosion-resistant material lining located on the body interior surface, the mixer and the unions of inlet and outlet of the reactants and having the located inside it perforated pipeline, which holes are disposed in pairs along the pipeline perimeter at the level of the column muddle midpoints of a column at the angle of 20° - 60° to the central axis of the column. The technical result of the invention consists in intensification of the contacting of the introduced components, the increased service life of the column lining layer and the raised conversion due to removal of the surplus of the water formed during the synthesis process.

EFFECT: the invention ensures intensification of the contacting of the introduced components, the increased service life of the column lining layer, the raised of conversion.

3 cl, 3 dwg

FIELD: chemical industry; methods of production of carbamide from carbon dioxide and ammonia.

SUBSTANCE: the invention is pertaining to the method of production of carbamide from carbon dioxide and ammonia. The method of production of carbamide is realized in the reactor of synthesis with the subsequent thermal distillation from the reaction mixture of the carbamate and partially ammonia in the high-pressure apparatus at heat input by means of the steam. The separated gas phase is directed for condensation into the high-pressure condenser, where gas condensation heat is transferred to the heat-carrier with formation of the steam A. The carbamide solution from the high-pressure apparatus is fed for the ammonium carbamate decomposition into the apparatus at the average pressure with usage of the heat carrier. At that as the heat carrier use the steam condensate produced after the high-pressure apparatus in the combination the steam A. The high-pressure condenser represents the submerged condenser. The installation for production of carbamide includes the reactor of the synthesis of carbamide, the high-pressure apparatus for the thermal distillation of the carbamate and ammonia from the solution of synthesis of carbamide with the heat supply by means of the heat carrier, and also contains the apparatus for ammonium carbamate decomposition at the average pressure. As the high-pressure condenser used for the gas phase condensation the installation contains the submerged condenser. The method of the installation upgrade consists that the existing high-pressure condenser is substituted for the submerged condenser. The technical result of the invention is reduction of the power inputs due to upgrade of the equipment and the combined usage of the scheme of recuperation of the heat of the heat carriers.

EFFECT: the invention ensures the reduced power inputs, the upgrade of the equipment, the combined usage of the scheme of recuperation of the heat of the heat carriers.

12 cl, 2 dwg

FIELD: chemical industry; methods and devices for production of carbamide.

SUBSTANCE: the invention is pertaining to the methods and devices for production of carbamide from ammonia and carbon dioxide. At realization of the method the reaction mixture from the synthesis reactor is fed in the stripper for the partial decomposition of the ammonium carbamate in the flow of the source carbon dioxide at the pressure practically equal to the pressure in the synthesis reactor. The stream of the source carbon dioxide is divided into two parts, one of which is routed into the stripper, and the other part is used as the working stream for injection of the gas stream from the stripper into the vertical condenser. The liquid stream from the stripper is fed at the stage of the subsequent decomposition of the ammonium carbamate, and the gaseous stream from the stripper is injected into the lower part of the vertical condenser for its mixing with source liquid ammonia. The liquid stream from the vertical condenser is fed into the synthesis reactor, butt from the gaseous stream absorb ammonia and carbon dioxide. The installation for production of carbamide consists of: the synthesis reactor; the scrubber for purification of the gaseous streams from the reactor from ammonia and carbon dioxide; the stripper for the partial decomposition of the ammonium carbamate; the vertical condenser, in which the mixing of the gas stream from the stripper with the source liquid ammonia takes place. The stripper is connected to the lines of feeding of the fluid stream from the reactor and the stream of the source carbon dioxide, and also is equipped with tool for injection of the gaseous stream from the stripper into the vertical condenser by the part of the stream of the source carbon dioxide. By the liquid stream the stripper is linked with the apparatuses for the subsequent decomposition of the ammonium carbamate and extraction of carbamide. The method of upgrading of the installation for production of carbamide consists in connection of the reactor of the synthesis to the stripper for the partial decomposition of the ammonium carbamate in the flow of the source carbon dioxide, in equipping the stripper with the tools for injection of the gaseous stream from the stripper into the vertical condenser with the part of the stream of the source carbon dioxide, and also in the availability of the lines of delivery of the gaseous mixture after the injector and the feeding line of the source liquid ammonia into the lower part of the vertical condenser. The technical result of the invention is the increased degree of conversion of the source reagents into carbamide at reduction of the scale of recirculation of the non-converted reactants.

EFFECT: the invention ensures the increased degree of conversion of the source reagents into carbamide at reduction of the scale of recirculation of the non-converted reactants.

11 cl, 2 ex, 2 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to a method of condensing carbamate through condensation of gaseous phase of carbon dioxide and ammonia into a liquid phase, which is carbamate in aqueous solution and optionally a solution which contains urea and non-reacting substances and liquid ammonia, in a submerged-type condenser, containing a given number of heat-exchange pipes in a bundle, meant for condensing carbamate, into each of which gaseous and liquid phases are fed simultaneously and independently from each other. The invention also relates to a submerged-type device for condensing carbamate.

EFFECT: increased efficiency and output of the method of condensing carbamate in the proposed device.

14 cl, 4 dwg

FIELD: process engineering.

SUBSTANCE: invention relates to corrosionproof fluid flow conducting parts and equipment comprising one or more such parts. Equipment component comprises first fluid corrosionproof flow conducting section that comprises first corrosionproof material and second fluid flow conducting section that comprises second material. First and second sections are, directly or indirectly, have their ends welded together in solid state to make integral fluid flow conducting part. Invention covers also the method of replacing at least one fluid flow conducting equipment part that proposes replacement component comprising first fluid flow conducting section that includes first material and second fluid flow conducting section that includes second material. Second material is, in fact, identical to that of equipment section whereat spare part is to be mounted. First and second sections are, directly or indirectly, have their ends welded together in solid state to make integral fluid flow conducting part. Space part is secured to equipment by flush butt welding of second material of second space part with material being, in fact identical, to that of equipment attachment section.

EFFECT: higher efficiency due to replacement with parts that feature improved corrosion resistance properties.

101 cl, 2 ex, 4 tbl, 14 dwg

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