Method and apparatus for producing carbamide

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

 

The invention relates to devices and methods for obtaining urea and can be used in the chemical industry and industry for the production of fertilizers.

Known equipment for production of urea from ammonia and carbon dioxide at elevated temperature and pressure, comprising a reactor, means for feeding into the reactor liquid ammonia and gaseous carbon dioxide (Whicharray, Bee. Synthesis and application of urea. - L.: Chemistry, 1970, p.178).

A known device for producing urea from ammonia and carbon dioxide at elevated temperature and pressure, comprising a reactor, means for feeding into the reactor liquid ammonia, liquid and gaseous carbon dioxide, a device for the evaporation of liquid carbon dioxide by heat transfer through the wall with brine (Technical gases, 2009, №2, p. 24).

The closest to the invention is known device for producing urea from ammonia and carbon dioxide at elevated temperature and pressure in the section of high pressure, comprising a reactor, a stripper, a condenser and a scrubber, means for supplying liquid ammonia, gaseous and liquid carbon dioxide in the section of high pressure, means for supplying liquid flows from the reactor to the stripper, the stripper on the stage of allocation of urea and recirculating the liquid flow, from the condenser to the reactor from the scrubber into the condenser, means for supplying gas streams from the reactor in the scrubber, from the stripper to the condenser, means for supplying recirculated liquid stream in a scrubber, a device for mixing liquid carbon dioxide, liquid ammonia, comprising a housing with means for entering liquid carbon dioxide, liquid ammonia and output the mixed stream, and located inside the housing coaxial with the body tapering nozzle, coupled with the means for entering liquid carbon dioxide (WO 2009/043365, SS 273/04, 2009, s, lines 1-8,14-27, 5, 6).

Known methods for producing urea from carbon dioxide and liquid ammonia synthesis reactor at elevated temperature and pressure, in which carbon dioxide in the synthesis reactor is sent to a gaseous form (Whicharray, Bee. Synthesis and application of urea. - L.: Chemistry, 1970, p.178).

Known methods for producing urea from carbon dioxide and liquid ammonia synthesis reactor at elevated temperature and pressure, in which carbon dioxide in the synthesis reactor is sent in the form of liquid carbon dioxide (Whicharray, Bee. Synthesis and application of urea. - L.: Chemistry, 1970, s-229; GB 1302424, SS 127/04, 1973). Liquefaction of carbon dioxide at a pressure lower than the pressure of the synthesis of urea, followed by the acai liquid carbon dioxide using a pump can reduce energy costs for compression of carbon dioxide.

A method of obtaining urea at elevated temperature and pressure in the installation comprising a section of high pressure, which includes a reactor, a stripper, a condenser and scrubber operating at almost the same pressure, and the method includes the interaction of ammonia and carbon dioxide in the reactor with the formation of the reaction mixture and separate the output from the reactor a liquid stream containing urea, ammonium carbamate and free ammonia in aqueous solution, and a gas stream containing mainly inert gases, the flow in the section of high pressure liquid and gaseous carbon dioxide feed liquid stream from the reactor to the stripper for the partial decomposition of ammonium carbamate and partial allocation of free ammonia in the current introduced into the stripper gaseous carbon dioxide to obtain a gas stream comprising ammonia and carbon dioxide mixed with water vapor, and liquid flow comprising urea and residual carbamate ammonium in odnoimennom solution, the feed liquid stream from the stripper on stage subsequent decomposition of ammonium carbamate and separation of ammonia and carbon dioxide with obtaining urea and recycled liquid stream containing ammonium carbamate in odnoimennom solution, the feed gas stream from the stripper in Conde who Sator for its partial absorption-condensation when mixed with ammonia and liquid flow from the scrubber, the feed liquid flow from the condenser to the reactor, the removal of ammonia and carbon dioxide gas stream from the reactor by contact with recycled liquid stream in the scrubber, and the flow of liquid carbon dioxide injected directly into the reactor and/or a capacitor (WO 2009/043365, SS 273/04, 2009, page 11, line 34 - p.12, line 31, figure 4). However, using this method, as mentioned above, can cause erosion damage to the equipment due to the occurrence of cavitation phenomena in direct contact easily evaporating carbon dioxide with high temperature environments in these devices.

The closest to the invention is a method of obtaining urea at elevated temperature and pressure in the installation comprising a section of high pressure, which includes a reactor, a stripper, a condenser and a scrubber, and the method includes the interaction of ammonia and carbon dioxide in the reactor with the formation of the reaction mixture and separate the output from the reactor a liquid stream containing urea, ammonium carbamate and free ammonia in aqueous solution, and a gas stream containing mainly inert gases, the flow in the section of high pressure streams of liquid and gaseous carbon dioxide, the flow of the liquid stream from the reactor to the stripper partially decomposed the I of ammonium carbamate and partial allocation of free ammonia in the current introduced into the stripper gaseous carbon dioxide to obtain a gas stream, comprising ammonia and carbon dioxide mixed with water vapor, and liquid flow comprising urea and residual carbamate ammonium in odnoimennom solution, the feed liquid stream from the stripper on stage subsequent decomposition of ammonium carbamate and separation of ammonia and carbon dioxide with obtaining urea and recycled liquid stream containing ammonium carbamate in odnoimennom solution, the feed gas stream from the stripper to the condenser to its partial absorption-condensation when mixed with ammonia and a liquid stream from the scrubber, the supply of the liquid flow from the condenser to the reactor, the removal of ammonia and carbon dioxide gas stream from the reactor by contact with recirculated liquid stream in the scrubber, and the flow of liquid carbon dioxide injected into the reactor and/or the capacitor after mixing with liquid ammonia (WO 2009/043365, SS 273/04, 2009, s, lines 1-8, figure 5).

A disadvantage of the known installation and known method is a significant possibility of erosion damage. The mixture of liquid carbon dioxide with liquid ammonia at a temperature lower than the temperature in the reactor or capacitor, it would seem that reduces the likelihood of cavitation. It is known, however, that by mixing these reagents between them runs fast R is the promotion of the formation of ammonium carbamate emitting a large amount of heat, consequently the temperature in the mixing zone may increase even up to higher values than the temperature in the reactor or capacitor. Thus, when using the known installation and known way, the possibility of damage due to the occurrence of cavitation phenomena only moved from one apparatus to another.

The technical result, which is aimed invention is to improve reliability of equipment used.

To achieve the specified result of the proposed device for producing urea from ammonia and carbon dioxide at elevated temperature and pressure in the section of high pressure, comprising a reactor, a stripper, a condenser and a scrubber, means for supplying liquid ammonia, gaseous and liquid carbon dioxide in the section of high pressure, means for supplying liquid flows from the reactor to the stripper, the stripper on the stage of allocation of urea and recycled liquid stream from the condenser to the reactor from the scrubber into the condenser, means for supplying gas streams from the reactor in the scrubber, from the stripper to the condenser, means for supplying recirculated liquid flow in the scrubber, a device for mixing liquid carbon dioxide with another process stream, comprising a housing with means on the I input of liquid carbon dioxide, enter another process stream and output the mixed stream, and located inside the housing coaxial with the body tapering nozzle, coupled with the means for entering liquid carbon dioxide, characterized in that the device for mixing the liquid carbon dioxide with another process stream is a device for mixing liquid carbon dioxide from a gaseous stream leaving the stripper or a capacitor, and includes a fitting entering the gaseous stream, and located inside the housing coaxially of the housing insert of variable cross-section in the form of a pipe, an inlet pipe which is tapering, and the output is expanding, and the insert is positioned in such a way that between the case and the insert formed by the annular gap.

To achieve this result also proposed a method of producing urea at elevated temperature and pressure in the installation comprising a section of high pressure, which includes a reactor, a stripper, a condenser and a scrubber, and the method includes the interaction of ammonia and carbon dioxide in the reactor with the formation of the reaction mixture and separate the output from the reactor a liquid stream containing urea, ammonium carbamate and free ammonia in aqueous solution, and a gas stream containing mainly inert gases, Pugachov section of the high pressure streams of liquid and gaseous carbon dioxide, feeding a liquid stream from the reactor to the stripper for the partial decomposition of ammonium carbamate and partial allocation of free ammonia in the current introduced into the stripper gaseous carbon dioxide to obtain a gas stream comprising ammonia and carbon dioxide mixed with water vapor, and liquid flow comprising urea and residual carbamate ammonium in odnoimennom solution, the feed liquid stream from the stripper on stage subsequent decomposition of ammonium carbamate and separation of ammonia and carbon dioxide with obtaining urea and recycled liquid stream containing ammonium carbamate in odnoimennom solution, the feed gas stream from the stripper to the condenser to its partial absorption-condensing at mixed with ammonia and a liquid stream from the scrubber, the supply of the liquid flow from the condenser to the reactor, the removal of ammonia and carbon dioxide gas stream from the reactor by contact with recycled liquid stream in the scrubber, and the flow of liquid carbon dioxide injected into the devices section of the high pressure after mixing with another process stream, wherein the stream of liquid carbon dioxide is mixed with the gaseous stream leaving the stripper or the capacitor in the device for mixing these streams included in the proposal the military installation, when the supply of liquid flow into the insert variable cross-section through a converging nozzle, and the gas flow - in case, that you are carrying out the evaporation of liquid carbon dioxide by contacting the insert part with the specified gas flowing in the inner space of the insert, followed by contacting the mixed flow at the outlet of the insert with the rest of the gaseous flow passing through the gap between the insert and the body

When used for mixing with liquid carbon dioxide gaseous stream leaving the stripper, and the combined stream is sent to the condenser. When used for mixing with liquid carbon dioxide gaseous stream exiting the condenser, and the combined stream is sent to the reactor.

Mixing the flow of liquid carbon dioxide with one of these gaseous flows using the proposed installation creates favorable conditions for the evaporation of liquid carbon dioxide, not involving resultline phenomena causing damage to the equipment.

The amount of gas in that part of the gaseous stream which contacts the inside of the insert with the flow of liquid carbon dioxide depends on the amount of liquid carbon dioxide and the temperature of both streams. It is preferable that the number of dollars is but to be so, to the mass ratio between the flow of liquid carbon dioxide and gazoobraznym the flow in the inner space of the insert was in the range of from 1:1.5 to 1:2,5. With less gas in the inner space of the insertion, the heat transferred from the gas to the stream of liquid carbon dioxide, can at low temperature liquid carbon dioxide to be sufficient for complete conversion of liquid carbon dioxide in the gas. This can lead to the penetration of droplets of the liquid phase on the inner wall of the pipeline and cause cavitation erosion of the breach. If you have more gas in the inner space of the insert increases the porosity of dispersed torch and difficult contact between the drops of liquid and gas. This can also lead to an increase in residual drops of the liquid phase in the gas flow and cause cavitation erosion fracture on the inner wall of the device and subsequent pipeline.

Means for transmitting liquid and gas flows from one machine section to the high pressure in the other can be made in the form of pipelines, which flows by gravity. For a more economical arrangement of the apparatus as such tools can be used is jectory, for example, for injection box liquid flow from the scrubber flow of liquid ammonia injection box gas stream from the stripper flow of liquid ammonia and/or flow of a solution of ammonium carbamate, etc.

The invention is illustrated in the attached figure 1-4. Figure 1 and 2 shows the options process flow diagram of the proposed installation, carrying out the proposed method, in which the flow of liquid carbon dioxide is mixed with the gaseous stream leaving the stripper, and send the mixed flow into the condenser, figure 3 - schematic diagram of the proposed installation, carrying out the proposed method, in which the flow of liquid carbon dioxide is mixed with the gaseous stream exiting the condenser, and send the mixed flow in the reactor figure 4 - the design of the device for shielding the flow of liquid carbon dioxide from a gaseous stream leaving the stripper or the condenser.

In accordance with figure 1 section of a high pressure unit for production of urea includes a reactor 1, the stripper 2, the condenser 3 and the scrubber 4, running at almost the same pressure, the pumps 5 and 6 for the supply of liquid ammonia and liquid carbon dioxide, a compressor 7 for supplying gaseous carbon dioxide, the ejector 8, the device 9 for mixing Zhidkov the carbon dioxide and gaseous flow, leaving the stripper 2, line 10 for supplying the flow of carbon dioxide from the pump 6 in the device 9, the pipe 11 for the flow of carbon dioxide from the compressor 7 in the stripper 2, line 12 for supplying a gas stream from the device 9 to the condenser 3, the pipe 13 for supplying liquid ammonia in the ejector 8, line 14 for supplying liquid stream from the reactor 1 in the stripper 2, line 15 for supplying liquid stream from the stripper 2 at the stage of allocation of urea and recycled liquid stream (not shown in figure 1), the pipes 16 and 17 for supplying liquid and gas flows from the condenser 3 to the reactor 1, the pipe 18 for supplying a gas stream from the reactor 1 in scrubber 4, line 19 to the gas stream from the stripper 2, device 9, the pipe 20 for supplying recirculated liquid flow in the scrubber 4, the pipe 21 for supplying a liquid stream from the scrubber 4 in the ejector 8, line 22 for supplying a gas stream from the scrubber 4 at the stage of allocation of urea and recirculated liquid flow line 23 for supplying liquid flow from the ejector 8 to the condenser 3.

Option process flow diagram of the proposed setup, shown in figure 2 differs from option a in figure 1 only by the fact that the pipelines 12 and 23 are connected not with the top, with the bottom part of the con is Satoru 3, accordingly, the pipe 16 is connected not with the bottom and with the upper portion of the condenser 3 and is intended for filing a joint liquid and gas flows from the condenser 3 to the reactor 1, and the pipe 17 is missing.

In accordance with section 3 of the high-pressure unit for production of urea includes a reactor 1, the stripper 2, the condenser 3 and the scrubber 4, running at almost the same pressure, the pumps 5 and 6 for the supply of liquid ammonia and liquid carbon dioxide, a compressor 7 for supplying gaseous carbon dioxide, the ejector 8, the device 9 for mixing the liquid carbon dioxide and gaseous stream exiting the condenser 3, the pipe 10 for supplying the flow of carbon dioxide from the pump 6 in the device 9, the pipe 11 for the flow of carbon dioxide from the compressor 7 in the stripper 2 the pipe 12 for supplying a gas stream from the device 9 into the reactor 1, the pipe 13 for supplying liquid ammonia in the ejector 8, line 14 for supplying liquid stream from the reactor 1 in the stripper 2, line 15 for supplying liquid stream from the stripper 2 at the stage of allocation of urea and recycled liquid stream (figure 3 not shown), the pipe 16 for supplying liquid flow from the condenser 3 to the reactor 1, the pipe 17 for supplying a gas stream from the condenser 3 in the device 9, the pipe 18 to the filing of the gas stream from the reactor 1 in scrubber 4, the pipe 20 for supplying recirculated liquid flow in the scrubber 4, the pipe 21 for supplying a liquid stream from the scrubber 4 in the ejector 8, line 22 for supplying a gas stream from the scrubber 4 at the stage of allocation of urea and recycled liquid stream, the ejector 24, pipe 25 for supplying liquid flow from the ejector 8 in the ejector 24, the pipe 26 for supplying a gas stream from the stripper 2 in the ejector 24, the pipe 27 for supplying a gas-liquid stream from the ejector 24 to the condenser 3.

In accordance with figure 4, the device 9 for mixing the liquid carbon dioxide with another process stream consists of a cylindrical body 28, the fitting 29 for liquid carbon dioxide fitting 30 to the input of another process stream, fitting 31 to output the mixed flow. The fitting 29 is connected to the nozzle 32 located centrally in the housing 28 and tapering in the direction of fitting the output 31. Inside the housing 28 is coaxially he placed the insert 33 of variable cross-section, an input section which is tapered, and the output is expanding. Between the insert 33 and the inner surface of the housing 28 is formed of a circular slot 34, which also has a variable cross-section. The insert 33 is fixed inside the housing 28 by means of a support plate 35. The nozzle 32 may be located in the same plane with the input overstimulate 33, either inside the insert 33.

The invention is also illustrated by the following examples describing the implementation of the proposed method in the proposed installation.

EXAMPLE 1. 20000 kg/h of liquid carbon dioxide with a temperature of -25 to 15°C from the pump 6 to line 10 and 110000 kg/h of a gaseous stream (a mixture of carbon dioxide, ammonia and water vapor from the upper part of the stripper 2) with a temperature of 180-190°C on line 19 enter the device 9 to the mixing of these flows (the flow ratio is 1:5,5) installation diagram of which is depicted in figure 1. The gaseous stream enters the device 9 through the nozzle 30. The flow of liquid carbon dioxide enters the device through the nozzle 29 and is directed in a converging nozzle 32. In the nozzle 32, the flow of liquid carbon dioxide is accelerated and at the exit of the nozzle forms a conical flame of liquid droplets dispersed in a gaseous environment. The torch revealed in the insert 33. The moving stream of liquid droplets entrain into the insert 33 from 20 to 25% of the gaseous stream, which ensures complete conversion of liquid carbon dioxide gas inside the insert 33. At the contact of the outer surface of the conical flare drops of liquid from the inner wall of the insert 33 drip stream begins to function as a piston and to transport gas from the input of a participant who and insert 33 to its output section in the free space inside the housing 28 of the device in the direction of the fitting 31.

The dispersing device 9 torch fluid in the gas phase allows you to create a large surface area of contact of the liquid with the gas, and the difference of the velocities of gas and liquid promotes turbulence and mixing of gas and liquid flows. All this contributes to the efficient flow in the torch of the processes of heat and mass transfer. Due to transfer of heat from a hot gas to a liquid is heated and vaporized. At the output section of the insert 33 of the liquid carbon dioxide is fully converted to gas. After the release of the gas stream with a temperature of 115-120°C of the insert 33 in the free space inside the housing 28 is a mixture of the gas flow with the rest of the gas stream from the stripper 2 (75-80%), passing through the gap 34 between the inner surface of the housing 28 and the insert 33.

The gap 34 between the insert 33 and the inner surface of the housing 28 has a variable cross-sectional area along the length of the insert 33. The narrowing of the insert 33 in the initial section provides the efficiency of the injection box stream of carbon dioxide gas. Expansion of the insert 33 and the narrowing of the gap 34 at the output section of the insert 33 can increase the flow rate of carbon dioxide gas at the outlet of the slit 34, which promotes a more efficient mixing of the gas streams in the free volume of the device after insertion 33. For the more effective the th mixing flows of the support plate 35, locking the insert within the housing 28 may be angled to the flow of the moving gas.

26000 kg/h of carbon dioxide gas with a temperature of 90-100°C from the compressor 7 through the pipeline 11 are received in the lower part of the stripper 2, where at a pressure of 14 MPa and a temperature of 175°C in the lower part up to 189°C in the upper part are the decomposition in a stream of carbon dioxide when heated steam greater part of the ammonium carbamate and the distillation of the excess ammonia from 204000 kg/h of water urea (odnoimennogo solution of urea and ammonium carbamate)formed in the reactor 1. The liquid stream from the bottom of the stripper 2 (120000 kg/h) pipe 15 serves at the final stage of decomposition of ammonium carbamate and distillation of ammonia emitting 62500 kg/h of urea and education 40500 kg/h of recycled liquid stream containing ammonium carbamate in odnoimennom solution, which pipe 20 enters the scrubber 4.

The mixed gas stream from the nozzle 31 of the device 9 through the pipe 12 enters the condenser 3, where the pressure of 13.5-14.5 MPa and a temperature of 165-175°C, the process of condensation-absorption of gases as a result of their mixing with ammonia (35500 kg/h) and an aqueous solution of ammonium carbamate (62500 kg/h) cooling the boiling steam condensate. The mixture of ammonia and an aqueous solution of ammonium carbamate pic is there in the condenser 3 through the pipe 23 of the ejector 8, where ammonia is supplied from the pump 5 through the pipe 13, and an aqueous solution of ammonium carbamate from the scrubber 4 through the pipeline 21. To improve the conditions of the condensation-absorption in the condenser 3 in the ejector 8 can also do a certain amount of urea melt from the bottom of the reactor 1.

Concentrated mednoammiachnyh solution of ammonium carbamate and not condensed gases from the condenser 3 is coming through the pipes 16 and 17, respectively, in the reactor 1, where the movement of the gas-liquid mixture from the bottom up is the process of conversion of ammonium carbamate into urea and water with simultaneous further condensation-absorption is not condensed gases. In the upper part of the reactor 1 is divided phases. The liquid phase (melt urea) is fed via line 14 to the stripper 2, and the gas phase, consisting mainly of inert gases mixed with ammonia - pipeline 18 in scrubber 4, where further absorption of ammonia by contact with recycled liquid stream entering the scrubber 4 through the pipeline 20. Gases from the scrubber 4 is sent through the pipeline 22 to the stage of education recirculated liquid flow to their final separation from ammonia.

EXAMPLE 2. The process is carried out analogously to example 1 with the setup scheme is shown in figure 2, with the corresponding difference is that p the currents from the device 9 and the ejector 8 is coming through the pipes 12 and 23 not at the top, and in the lower part of the condenser 3, and formed in the condenser 3 gas-liquid mixture without separation derived from the upper part of the condenser 3 through the pipe 16 into the reactor 1.

EXAMPLE 3. The process is carried out analogously to example 1 on the installation, the scheme of which is shown in Fig. 3. 20000 kg/h of liquid carbon dioxide with a temperature of -25 to -15°C from the pump 6 to line 10 and 12,000 kg/h of a gaseous stream (a mixture of carbon dioxide, ammonia and water vapor from the upper part of the condenser 3) with a temperature of 170-175°With the pipe 17 are received in the device 9 to the mixing of these flows (the flow ratio is 1.7:1). The device 9 is the same as in the installation, the diagram of which is depicted in figure 1. Liquid ammonia (35500 kg/h) pump 5 through the pipeline 13 is supplied to the ejector 8, injective aqueous solution of ammonium carbamate (50500 kg/h)flowing through the pipeline 21 from the scrubber 4. To improve the subsequent condensation-absorption of gases in the condenser 3 in the ejector 8 can also do a certain amount of urea melt from the bottom of the reactor 1. Gaseous carbon dioxide (26000 kg/h) of the compressor 7 through the pipe 11 enters the lower part of the stripper 2, where the pressure of 13.5-14.5 MPa and a temperature of 170-190°C is the decomposition in a stream of carbon dioxide when heated steam greater part of the ammonium carbamate and distillation castesbeiana ammonia from urea melt (204000 kg/h), formed in the reactor 1. The liquid stream from the bottom of the stripper 2 (120000 kg/h) pipe 15 serves at the final stage of decomposition of ammonium carbamate and distillation of ammonia emitting urea and the formation of recirculated liquid stream containing ammonium carbamate in odnoimennom solution, which pipe 20 enters the scrubber 4. The gas stream from the stripper 2 (110000 kg/h) pipe 26 enters the ejector 24, a work flow in which liquid is flowing out of the ejector 8 and the pipe 25. Mixed gas-liquid stream from the ejector 24 is fed via a pipe 27 to the condenser 3, where the pressure of 13.5-14.5 MPa and a temperature of 165-175°C, the process of condensation-absorption of gases in mixture with ammonia and an aqueous solution of ammonium carbamate when cooled boiling steam condensate. Concentrated mednoammiachnyh solution of ammonium carbamate from the condenser 3 and the gas flow from the device 9 to line 16 and 12, respectively, come into the reactor 1. The reactor 1 and the scrubber 4 work the same as in the installation, the diagram of which is depicted in figure 1.

1. Device for producing urea from ammonia and carbon dioxide at elevated temperature and pressure, contains a section of high pressure, comprising a reactor, a stripper, a condenser and a scrubber, a slave is supposed to be almost the same pressure, means for supplying liquid ammonia, gaseous and liquid carbon dioxide in the section of high pressure, means for supplying liquid flows from the reactor to the stripper, the stripper on the stage of allocation of urea and recycled liquid stream from the condenser to the reactor from the scrubber into the condenser, means for supplying gas streams from the reactor in the scrubber, from the stripper to the condenser, means for supplying recirculated liquid stream in a scrubber, a device for mixing liquid carbon dioxide with another process stream, comprising a housing with means for entering liquid carbon dioxide, enter another process stream and output the mixed flow and located inside the housing coaxial with the body tapering nozzle, coupled with the means for entering liquid carbon dioxide, characterized in that the device for mixing the liquid carbon dioxide with another process stream is a device for mixing liquid carbon dioxide from a gaseous stream leaving the stripper or a capacitor, and includes a fitting entering the gaseous stream, and located inside the housing coaxially of the housing insert of variable cross-section in the form of a pipe, an inlet pipe which is tapering, and the output is expanding, and the insert is located so between the case and the insert formed by the annular gap.

2. A method of producing urea at elevated temperature and pressure in the installation comprising a section of high pressure, which includes a reactor, a stripper, a condenser and a scrubber, and the method includes the interaction of ammonia and carbon dioxide in the reactor with the formation of the reaction mixture and separate the output from the reactor a liquid stream containing urea, ammonium carbamate and free ammonia in aqueous solution, and a gas stream containing mainly inert gases, the flow in the section of high pressure streams of liquid and gaseous carbon dioxide, the flow of the liquid stream from the reactor to the stripper for the partial decomposition of ammonium carbamate and partial allocation of free ammonia in the current introduced into the stripper gaseous carbon dioxide to obtain a gas stream comprising ammonia and carbon dioxide mixed with water vapor, and liquid flow comprising urea and residual carbamate ammonium in the water-ammonia solution, the feed liquid stream from the stripper on stage subsequent decomposition of ammonium carbamate and separation of ammonia and carbon dioxide with obtaining urea and recycled liquid stream containing ammonium carbamate in aqueous ammonia solution, the feed gas stream from the stripper to the condenser to its partial absorption-condensation when mixed with ammonia and a liquid stream from the scrubber, the feed liquid flow from the condenser to the reactor, the removal of ammonia and carbon dioxide gas stream from the reactor by contact with recycled liquid stream in the scrubber, and the flow of liquid carbon dioxide injected into the devices section of the high pressure after mixing with another process stream, wherein the stream of liquid carbon dioxide is mixed with the gaseous stream leaving the stripper or condenser, device for mixing these streams according to claim 1 when the supply of liquid flow into the insert variable cross-section through a converging nozzle, and the gas flow - in case, that you are carrying out the evaporation of liquid carbon dioxide by contact box with a part of the specified gas flowing in the inner space of the insert, followed by contacting the mixed flow at the outlet of the insert with the rest of the gaseous flow passing through the gap between the insert and the housing.

3. The method according to claim 2, characterized in that the flow of liquid carbon dioxide is mixed with the gaseous stream leaving the stripper, and the mixed stream is sent to the condenser.

4. The method according to claim 2, characterized in that the flow of liquid carbon dioxide is mixed with the gaseous stream exiting the condenser, and the mixed stream is directed in the region of the actor.



 

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FIELD: chemistry.

SUBSTANCE: invention relates to aldimines used to produce a polymer precursor, obtained via reaction of at least one sterically hindered aliphatic aldehyde A of formula with an aliphatic amine B, where all values of substitutes are given in the claim, via a condensation reaction with splitting of water, a product containing an aldimine-containing compound, and use thereof as a protected cross-linking agent for the polymer precursor and as a source of amines [H2N]m-R4-[XH]y (B).

EFFECT: obtaining polymer precursors containing isocyanate groups, which are characterised by high stability during storage.

15 cl, 51 ex, 4 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to aldimines used to produce a polymer precursor, obtained via reaction of at least one sterically hindered aliphatic aldehyde A of formula with an aliphatic amine B, where all values of substitutes are given in the claim, via a condensation reaction with splitting of water, a product containing an aldimine-containing compound, and use thereof as a protected cross-linking agent for the polymer precursor and as a source of amines [H2N]m-R4-[XH]y (B).

EFFECT: obtaining polymer precursors containing isocyanate groups, which are characterised by high stability during storage.

15 cl, 51 ex, 4 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to aldimines used to produce a polymer precursor, obtained via reaction of at least one sterically hindered aliphatic aldehyde A of formula with an aliphatic amine B, where all values of substitutes are given in the claim, via a condensation reaction with splitting of water, a product containing an aldimine-containing compound, and use thereof as a protected cross-linking agent for the polymer precursor and as a source of amines [H2N]m-R4-[XH]y (B).

EFFECT: obtaining polymer precursors containing isocyanate groups, which are characterised by high stability during storage.

15 cl, 51 ex, 4 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to aldimines used to produce a polymer precursor, obtained via reaction of at least one sterically hindered aliphatic aldehyde A of formula with an aliphatic amine B, where all values of substitutes are given in the claim, via a condensation reaction with splitting of water, a product containing an aldimine-containing compound, and use thereof as a protected cross-linking agent for the polymer precursor and as a source of amines [H2N]m-R4-[XH]y (B).

EFFECT: obtaining polymer precursors containing isocyanate groups, which are characterised by high stability during storage.

15 cl, 51 ex, 4 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing highly concentrated methylal from formaldehyde and methanol via a reaction-fractionation method involving preliminary mixing of aqueous solution of formaldehyde and methanol, feeding the obtained mixture into a pre-reaction zone, followed by feeding the mixture of unreacted initial reagents, the formed methaylal and water into a fractionation column, having a reaction-fractionation zone lying above the fractionation column still, feeding an extraction agent into the fractionation zone of the column lying above the reaction-fractionation zone, condensing a product containing over 98 wt % methylal tapped from the top of the column, cleaning the methylal from impurities, characterised by that methanol is fed for preliminary mixing in amount of 95-50% of the amount required for implementing the method, and the remaining portion of methanol in amount of 5-50% of the amount required to implement the method is fed into the fractionation column below the reaction-fractionation zone and purification of methylal is carried out via azeotropic rectification with isopentane which is fed in amount of 15-50% in terms of the amount of the purified methylal, with extraction of the desired methylal as a bottom product, and the top product in form of the mixture of isopentane primarily with methylal, methanol and water, followed by condensation and demixing the top product into hydrocarbon and water layers, returning a portion of the hydrocarbon layer into the azeotropic rectification column as reflux liquid, and the remaining portion of the hydrocarbon layer is fed into this column and the water layer is returned into the fractionation column below the reaction-fractionation zone.

EFFECT: use of present method reduces the number of steps of purifying methylal from impurities and reduces residual content of methanol and formaldehyde in residual water.

4 cl, 4 ex, 1 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing (meth)acrylic esters (F) based on alcohols having at least one carbon-carbon triple bond, characterised by that at least one alcohol having at least one carbon-carbon triple bond of formula (1) where R1 denotes hydrogen, alkyl having 1-18 carbon atoms; alkyl having 2-18 carbon atoms, aryl having 6-12 carbon atoms, cycloalkyl having 5-12 carbon atoms, interrupted, if necessary, by one or more oxygen and/or sulphur atoms and/or one or more substituted or unsubstituted amino groups, or a 5-6-member heterocycl having oxygen, nitrogen and/or sulphur atoms, wherein said residues can be substituted with aryl, alkyl, aryloxy, alkyloxy, heteroatoms/or heterocycles, respectively, and R2 denotes alkylene having 1-20 carbon atoms, cycloalkylene having 5-12 carbon atoms, arylene having 6-12 carbon atoms, or alkylene having 2-20 carbon atoms interrupted by one or more oxygen and/or sulphur atoms and/or one or more substituted or unsubstituted amino groups and/or one or more cycloalkyl groups, -(CO)-, -O(CO)O, -(NH)(CO)O-, -O(CO)(NH)-, -O(CO)- or -(CO)O, where the names of the residues can be replaced with aryl, alkyl, aryloxy, alkyloxy, heteroatoms and/or heterocycles respectively, n is a whole number from 0 to 3, preferably from 0 to 2 and more preferably from 1 to 2 and X; for each i=0 to n can be independently selected from a group comprising -CH2-CH2-O-, -CH2-CH(CH3)-O-, -CH(CH3)-CH2-O-, -CH2-C(CH3)2-O-, -C(CH3)2-CH2-O-, -CH2-CHVin-O-, -CHVin-CH2-O-, -CH2-CHPh-O- and -CHPh-CH2-O-, preferably from a group comprising -CH2-CH2-O-, -CH2-CH(CH3)-O- and -CH(CH3)-CH2-O-, and more preferably CH2-CH2-O-, where Ph denotes phenyl and Vin denotes vinyl, wherein the hydroxy groups of the alcohol are primary or secondary, esterified in the presence of at least one enzyme (E) with (meth)acrylic acid or re-esterified with at least one (meth)acrylic ester (D).

EFFECT: use of the present method enables to obtain esters of an acid based on alcohols which have carbon-carbon triple bonds with good output and low colour indices.

5 cl, 3 ex

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 120-130°C 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 130-150°C 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 80-150°C, 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 120-170°C 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 80-150°C, 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 120-170°C 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: chemistry.

SUBSTANCE: invention relates to obtaining urea from ammonia and carbon dioxide. As a result of ammonia and carbon dioxide interaction at high pressure in reactor obtained is water solution, which contains urea, ammonium carbamate and ammonia. From obtained water solution carbamate and ammonia are separated by decomposing carbamate and thermal evaporation of ammonia and carbon dioxide in stripping apparatus, obtaining ammonia and carbon dioxide, which after that are again condensed in condenser obtaining carbamate, which is returned to reactor. All stages together with reaction of synthesis are carried out in fact at one and the same pressure. In addition, into reactor additionally supplied is passivating oxygen, obtained as a result of interaction waste gases, which contain carbon dioxide, ammonia and passivating oxygen which did not take part in the reaction, are removed from reactor and are supplied into bottom part of stripping apparatus for passivation of at least part of its internal surfaces. Installation for obtaining urea contains communicating with each other and forming closed high pressure contour reactor, stripping apparatus, condenser, section of final urea purification and pipelines for supply into reactor of carbon dioxide and ammonia. It is equipped with pipeline for supply into reactor of passivating oxygen and pipeline for connecting upper part of reactor with bottom part of stripping apparatus.

EFFECT: ensuring even and efficient passivation of all apparatuses of high pressure contour.

13 cl, 2 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to production of urea from ammonia and carbon dioxide. A reaction mixture is obtained in a synthesis reactor at given high pressure as a result of a reaction between NH3 and CO2, where the said reaction mixture contains urea, ammonium carbamate and free ammonia in aqueous solution, from which ammonium carbamate and ammonia are extracted and subsequently returned to the synthesis reactor. Ammonium carbamate and ammonia are extracted from the reaction mixture on process steps for decomposing ammonium carbamate to NH3 and CO2 and their stripping and on the next process step for their re-condensation to obtain ammonium carbamate which is returned to the synthesis reactor. The reaction mixture obtained as a result of the reaction between ammonia and carbon dioxide is taken to the process steps for decomposition and stripping using a pump.

EFFECT: changing production capacity by changing pump parameters, possibility of horizontal assembling, reduced expenses on servicing and increased safety.

12 cl, 2 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to a method for synthesis of 13C-urea by reacting ammonia with carbon monoxide 13CO in the presence of oxygen, taken in molar ratio ranging from 8.9:2.8:1 to 4:2:1 at 15-25°C and pressure of 25-35 atm. The catalyst used is selenium powder taken in molar ratio Se:13CO ranging from 1:790 to 1:158. The solvent used is tetrahydrofuran or a mixture of tetrahydrofuran and methanol.

EFFECT: invention enables to obtain urea containing the stable 13C isotope with isotopic purity of not less than 99% in a single step.

1 cl, 6 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

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