Method and installation for production of carbamide

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

 

The invention relates to a method and a device for producing urea from ammonia and carbon dioxide.

Known methods for producing urea by the interaction of ammonia and carbon dioxide at elevated temperatures and pressures with the formation of the melt synthesis of urea containing urea, water, ammonium carbamate, ammonia and carbon dioxide by the decomposition of ammonium carbamate in water synthesis of urea during the heat input at several stages of pressure with formation of an aqueous solution of urea and gas flows, condensation-absorption of gas streams using aqueous absorbents and education aqueous solution of ammonium salts (UAS), is recycled to the stage of education Plava synthesis of urea by evaporation of an aqueous solution of urea and the formation of solid urea (Whicharray, Bee. Synthesis and application of urea. L.: Chemistry, 1970, s-208).

The closest to the proposed method to the technical essence is a method of obtaining urea interaction of ammonia and carbon dioxide in the synthesis zone at elevated temperatures and pressures with the formation of flow of the melt of urea containing urea, water, ammonium carbamate, ammonia and carbon dioxide by distillation stream Plava synthesis of urea while applying heat from an external source at two levels Yes the population, preferably at 15-25 and 2-5 kgf/cm2with the formation of an aqueous solution of urea and gases of distillation, condensation-absorption of the gases of distillation with the use of water absorbent material, and the formation of aqueous solutions of UAS, the recirculation of the aqueous solution of UAS from the stage of condensation-absorption of gases from the distillation of the second stage to the stage of condensation-absorption of gases from the distillation of the first stage and from the stage of condensation-absorption of gases from the distillation of the first stage in the synthesis zone, the evaporation of an aqueous solution of urea in several stages of heat exchange between the gases of distillation of the first stage and an aqueous solution of urea at the stage of preliminary evaporation, producing solid urea (US 3366682, 260-555, 1968). In this way, the heat released by cooling and partial condensation of the gases of distillation the first step is used to remove part of the water from a solution of urea, resulting in lower total cost of heating steam in the production of urea.

Known equipment for production of urea, comprising a reactor for the synthesis of urea, distilling at several stages of pressure Plava urea obtained in the synthesis, the apparatus for evaporation of an aqueous solution of urea, obtained at the last stage of distillation, the apparatus for condensation-absorption of gases, disti the population, means for supplying ammonia and carbon dioxide in the reactor for the synthesis of urea, the urea melt from the synthesis reactor in the apparatus for distillation, an aqueous solution of urea from the apparatus for distillation of the last stage in the apparatus for evaporation, distillation gases from the apparatus for distillation in the apparatus for condensation-absorption, solution UAS of apparatus for distillation of lower pressure in the apparatus for distillation higher pressure and apparatus for distillation of high pressure in the synthesis reactor (Whicharray, Bee. Synthesis and application of urea. L.: Chemistry, 1970, s-208).

Closest to the proposed installation is an installation for producing urea, includes a reactor for the synthesis of urea, the device with a supply of heat from an external source for the distillation of water urea obtained in the synthesis reactor at a first pressure, a device with a supply of heat from an external source for the distillation of water urea at a second pressure, the apparatus for evaporation by heating an aqueous urea solution obtained in the second stage of distillation, the apparatus for condensation-absorption cooling gases of distillation both stages, the heat exchanger-recuperator for heat exchange between the gases of distillation of the first stage and an aqueous solution of urea, means for feeding am IACA and carbon dioxide in the reactor for the synthesis of urea, Plava urea from the synthesis reactor in a device for distillation of the first stage and from the device to the first distillation stage in apparatus for the distillation of the second stage, an aqueous solution of urea from the apparatus for distillation of the second stage of the heat exchanger-the heat exchanger and from the heat exchanger-the heat exchanger in the apparatus for subsequent evaporation, distillation gases from the device for distillation of the first stage of the heat exchanger-the heat exchanger and from the heat exchanger-the heat exchanger in the apparatus for condensation-absorption of the first stage, the gases distilled from the apparatus for distillation of the second stage in the apparatus for condensation-absorption of the second stage, the solution of the UAS of the apparatus for condensation-absorption the second stage in the apparatus for condensation-absorption of the first stage and of the apparatus for condensation-absorption of the first stage in the synthesis reactor (US 3366682, 260-555, 1968). In this setting, compared with other known installations, reduced the number of heat exchangers that use energy (steam heating) from external sources.

The technical result, which directed the present invention is to further increase the degree of heat recovery of the production cycle and reduce the amount of heat exchangers using steam heating from external sources.

To achieve this result, the pre is a false method of producing urea by the interaction of ammonia and carbon dioxide in the synthesis zone at elevated temperatures and pressures with the formation of flow of the melt of urea, containing urea, water, ammonium carbamate, ammonia and carbon dioxide by distillation stream of water urea while applying heat at two levels of pressure, preferably at 15-25 and 2-5 kgf/cm2with the formation of an aqueous solution of urea and gases of distillation, condensation-absorption cooling gases of distillation with the use of water absorbent material, and the formation of aqueous solutions of ammonium salts, the recirculation of the aqueous solution of ammonium salts from the stage of condensation-absorption of gases from the distillation of the second stage to the stage of condensation-absorption of gases from the distillation of the first stage and from the stage of condensation-absorption of gases from the distillation of the first stage in the synthesis zone, the evaporation of an aqueous solution of urea in several stages of heat exchange between the gases of distillation of the first stage and an aqueous solution of urea at the stage of preliminary evaporation, characterized in that the distillation of the water of urea on the first pressure hold a series of two zones, the first of which the distillation is carried out o adiabatically or heat input, and the second distillation is conducted while applying heat in a current of carbon dioxide.

To achieve this result also proposed a device for producing urea, includes a reactor for the synthesis of urea, the device with a supply of heat from outside is his source for the distillation of water urea, obtained in the synthesis reactor at a first pressure, a device with a supply of heat for the distillation of water urea at a second pressure, the apparatus for evaporation by heating an aqueous urea solution obtained in the second stage distillation device for condensation-absorption cooling gases of distillation both stages, the heat exchanger-recuperator for heat exchange between the gases of distillation of the first stage and an aqueous solution of urea, means for feeding ammonia and carbon dioxide in the reactor for the synthesis of urea, the urea melt from the synthesis reactor in a device for distillation of the first stage and from the device to the first distillation stage in a device for the second distillation stage, an aqueous solution of urea from the device for distillation of the second stage of the heat exchanger-the heat exchanger and from the heat exchanger-the heat exchanger in the apparatus for subsequent evaporation, distillation gases from the device for distillation of the first stage of the heat exchanger-the heat exchanger and from the heat exchanger-recuperator in a device for condensation-absorption of gases of the first stage distillation, distillation gases from the apparatus for distillation of the second stage in the device for condensation-absorption of gases from the distillation of the second step, a solution of ammonium salts of the device for condensation-absorption of gases diest is LaCie second stage device for condensation-absorption of gases from the distillation of the first stage and from device for condensation-absorption of gases from the distillation of the first stage in the synthesis reactor, characterized in that the device for distilling the first stage consists of a column of the first distillation stage and film heat exchanger, and the installation includes optional means for supply of urea melt from the column of the first distillation stage, in film heat exchanger and means for supplying carbon dioxide film heat exchanger.

Holding in the proposed method and using the proposed installation of the distillation process the first stage in two zones, the second of which the distillation is carried out in a current of carbon dioxide, allows you to change the composition of the gases of distillation the first stage in the composition of these gases increases the amount of carbon dioxide. This leads to an increase of thermal capacity of these gases and expands the use of heat instead of applying heat from an external source for heating an aqueous solution of urea at the stage of preliminary evaporation, and heating the melt of urea in the second stage of distillation. However, depending on specific conditions, the distillation process is the first stage in the first zone can be conducted with a supply of heat, and without it.

In the framework of the invention can be implemented in various modifications, which are particular cases of its implementation.

In one modification of the method of gases from the first zone is the first stage of distillation is directed to a stage of condensation-absorption of gases from the distillation of the first stage after their heat transfer in series with the urea melt in the second stage of its distillation and aqueous solution urea at the stage of preliminary evaporation, and the gases from the second zone of the first stage distillation return in the first zone of the first stage of distillation and/or attached to the gases from the first zone of the first stage distillation before heat exchange with the melt of urea in the second stage of its distillation. Installation in this case, as means for supplying gases distilled from the device to the first distillation stage in the heat exchanger-recuperator includes means for supplying gases distilled from the distillation columns of the first degree in the area of the heating device to a second distillation stage, means for feeding gases distilled from the film of the heat exchanger to the distillation column of the first stage and/or in the zone of the heating device to the second distillation stage and means for conducting gases from the distillation zone heating device for distillation of the second stage of the heat exchanger-recuperator.

In another modification of the method of gases from the first zone of the first stage distillation sent directly to the stage of condensation-absorption of gases from the distillation of the first stage, and the gases from the second zone of the first stage of distillation is directed to a stage of condensation-absorption of gases from the distillation of the first stage after their heat transfer in series with the urea melt in the second stage of its distillation and aqueous solution ka is bamiga at the stage of preliminary evaporation. Installation in this case, as means for supplying gases distilled from the device to the first distillation stage in the heat exchanger-recuperator includes means for supplying gases distilled from the film heat exchanger in the heating zone of the device to the second distillation stage and from the heating zone of the device for distillation of the second stage of the heat exchanger-the heat exchanger and further comprises means for supplying gases distilled from the distillation columns of the first stage directly to the device for condensation-absorption of gases from the distillation of the first degree.

In the third modification of the method of gases from the first zone of the first stage distillation sent directly to the stage of condensation-absorption of gases from the distillation of the first stage, and the gases from the second zone of the first stage of distillation is directed to a stage of condensation-absorption of gases from the distillation of the first stage after heat exchange with an aqueous solution of urea at the stage of preliminary evaporation. Installation in this case, as means for supplying gases distilled from the device to the first distillation stage in the heat exchanger-recuperator includes means for supplying gases distilled from the film heat exchanger in the heat exchanger-recuperator and further comprises means for supplying gases distilled from the distillation columns p is pout steps directly into the device for condensation-absorption of gases from the distillation of the first stage. Heat input into the heating zone of the device to the second distillation stage is from an external source.

The invention is illustrated in the accompanying figures 1 to 3, which depicts the schema of facilities, the specific embodiments of the invention and implementing the above modifications of the proposed technique.

In accordance with figure 1, the device for producing urea involves the synthesis reactor urea 1, the device for distillation of water urea obtained in the reactor 1, consisting of columns of the first distillation stage 2 and connected with it consistently film heat exchanger 3, a device for distillation of water of urea in the second pressure stage, consisting of columns of the second distillation stage 4, the regenerative heat exchanger 5 and the separator 6, the apparatus for pre-evaporation of an aqueous solution of urea, consisting of a separator 7 and a heat exchanger-the heat exchanger 8, the device 9 for condensation-absorption cooling gases from the distillation of the second stage, which represents a shell-and-tube a heat exchanger device for condensation-absorption cooling gases from the distillation of the first stage, consisting of the washing of the column 10, the external heat exchanger 11, condenser return ammonia 12 and washing scrubber 13, a pump 14 for supplying ammonia and to Pressor 15 for supplying carbon dioxide into the reactor 1, the pipe 16 for supplying the urea melt from the reactor 1 into the distillation column 2, line 17 for supplying carbon dioxide film heat exchanger 3, the pipe 18 for feeding the melt of urea from the film of the heat exchanger 3 in the column of the second distillation stage 4, line 19 for supplying an aqueous solution of urea from the separator 6 to the separator 7, the pipe 20 for supplying an aqueous solution of urea from the heat exchanger-the heat exchanger 8 in the apparatus for further evaporation (figure 1 not shown), the pipe 21 for supplying gases distilled from the column 2 in the tube space of the regenerative heat exchanger 5, line 22 for supplying gas distilled from the regenerative heat exchanger 5 in the annulus of the heat exchanger-recuperator 8, line 23 for supplying gases distilled from the heat exchanger-the heat exchanger 8 in the external heat exchanger 11, the pipe 24 for supplying the gases distilled from the distillation columns 4 in the device 9 for condensation-absorption of gases from the distillation of the second stage, the pump 25 to the feed solution UAS from the device 9 for condensation-absorption of gases from the distillation of the second stage in the external heat exchanger 11, the pump 26 for supplying solution UAS from the wash column 10 in the synthesis reactor 1, the pipe 27 for filing return of ammonia from the condenser 12 to the pump 14, the pipe 28 to release the cleansing is the R from ammonia inert gas atmosphere, the pipe 29 for supplying inert gas mixed with ammonia absorber in the tail (figure 1 not shown), the pipe 30 for supplying the juice of a pair of heat exchanger-recuperator 8 at the point of condensation of vapor phase evaporation (figure 1 not shown), the pipe 32 for supplying gases distilled from the film of the heat exchanger 3 in column 2, line 31 for supplying gases distilled from the film heat exchanger 3 into the pipe 21.

The installation shown in figure 2, differs from the setup depicted in figure 1, only the fact that the pipeline 21 is designed to supply gases distilled from the column 2 directly in the external heat exchanger 11, the conduit 31 for the supply of the gases distilled from the film of the heat exchanger 3 in the tube space of the regenerative heat exchanger 5, and the pipe 32 is missing.

The installation is shown in figure 3, differs from the setup shown in figure 2, the conduit 31 is designed to supply gases distilled from the film heat exchanger 3 directly into the annulus of the heat exchanger-recuperator 8, line 22 is absent, and the heat exchanger 5 includes means for supplying steam from an external source, and drain.

The invention is also illustrated by the following examples 1-3, which describes a specific embodiment predlojeno what about the method and operation of the proposed installation.

EXAMPLE 1. In accordance with figure 1 in synthesis 1 liquid ammonia is supplied by a pump 14, carbon dioxide, supplied by a compressor 15, and return the solution UAS supplied by a pump 26. In the column 1 at a pressure of 180 to 200 kgf/cm2and temperature 180-195°With the synthesis of urea with the formation of water (gas-liquid mixture containing urea, water, ammonium carbamate, is not converted into urea and excess ammonia. Plav throttled to a pressure of 15-25 kg/cm2and through the pipeline 16 is supplied at a temperature of 125°in the column of the first distillation stage 2, provided the mass - and heat transfer devices, where the input of heat or without the decomposition of part of the ammonium carbamate and the allocation of water of ammonia and carbon dioxide. The water from the column 2 is fed in the film heat exchanger 3, heated by steam, where at the same pressure and 150-165°completes the process of distillation. In the film heat exchanger 3 through the pipe 17 enters the portion of the carbon dioxide from the compressor 15. Gases from the film heat exchanger 3 with a temperature 148-150°come through the pipe 32 in column 2, where again in contact with the melt of urea, heating it up 138-140°or, partially or completely, through the conduit 31 into the pipe 21. The floating of the film heat exchanger 3 throttled to a pressure of 1.5 to 5 kgf/cm and the pipe 18 enters the distillation column of the second stage 4, where at the specified pressure continues decomposition of the ammonium carbamate and the allocation of water of ammonia and carbon dioxide, culminating in the regenerative heat exchanger 5 and the separator 6. Recuperative heat exchanger 5 is heated by the gases of distillation of the first stage, coming into its annulus from the column 2 and the film heat exchanger 3 (directly or through column 2) through the pipeline 21. The urea solution from the separator 6, practically exempt from UAS, throttled to atmospheric pressure and the pipe 19 into the separator 7 and later in tube heat exchanger-the heat exchanger 8, where in the film mode, there is a partial evaporation of water from the solution by heat exchange with the gases of distillation coming into the annulus of the heat exchanger-recuperator 8 of the annulus regenerative heat exchanger 5 through the pipeline 22. The urea solution concentration ˜78% of the heat exchanger-recuperator 8 goes on further evaporation and granulation by known methods through the pipeline 20. Gases from the distillation of the second stage of the columns 4 are condensed in the apparatus 9 with the formation of a dilute solution of UAS. Gases from the distillation of the first stage with an admixture of liquid products of condensation smartrange space heat exchanger-recuperator 8 comes with a temperature of 110-115° With external heat exchanger 11 wash column 10. In these devices is condensation-absorption distillation gases when in contact with water, liquid ammonia and the solution UAS obtained by condensation-absorption of gases from the distillation of the second stage in the apparatus 9. Removed from the top of the wash column purified ammonia gas is condensed by cooling water in the condenser 12 and is returned through the pipe 27 into the suction line of the pump 14. Not condensed gases are washed from the remnants of the ammonia water in the scrubber 13 and are vented to atmosphere through the pipeline 28. Formed in the bottom of the wash column 10 and the external heat exchanger 11 a concentrated solution of UAS is returned to the synthesis reactor 1 pump 26. A pair of separator 7 and the heat exchanger 9 are received by pipeline 29 sanitary absorber (not shown in figure 1). A pair of heat exchanger-the heat exchanger 8 through the pipeline 30 arrive at the point of condensation of the vapor phase evaporation (not shown in figure 1).

EXAMPLE 2. The process carried out at the facility, the scheme of which is shown in figure 2, mainly analogously to example 1. The difference lies in the fact that the gases from the film heat exchanger 3 with a temperature 148-150°proceed through the conduit 31 into the tube space of the regenerative heat exchanger 5 and then into the annulus of the heat exchanger is of recuperator 8, and from there to the external heat exchanger 11 wash column 10, which also receives gases from the column 2 through the pipe 21. The urea solution concentration ˜84% of the heat exchanger-recuperator 8 goes on further evaporation and granulation by known methods through the pipeline 20.

EXAMPLE 3. The process carried out at the facility whose schema is shown in figure 3, mainly analogously to example 2. The difference lies in the fact that the gases from the film heat exchanger 3 with a temperature 148-150°proceed through the conduit 31 in the annulus of the heat exchanger-recuperator 8, bypassing the annulus of the heat exchanger 5, and from there to the external heat exchanger 11 wash column 10, which also receives gases from the column 2 through the pipe 21. The heat exchanger 5 is heated by steam from an external source. The urea solution concentration ˜80% of the heat exchanger-recuperator 8 goes on further evaporation and granulation by known methods through the pipeline 20.

1. A method of producing urea by the interaction of ammonia and carbon dioxide in the synthesis zone at elevated temperatures and pressures with the formation of flow of the melt of urea containing urea, water, ammonium carbamate, ammonia and carbon dioxide by distillation stream of water urea while applying heat at two levels of pressure, predpochtitel is about when and 15-25 2-5 kgf/cm 2with the formation of an aqueous solution of urea and gases of distillation, condensation-absorption cooling gases of distillation with the use of water absorbent material, and the formation of aqueous solutions of ammonium salts, the recirculation of the aqueous solution of ammonium salts from the stage of condensation-absorption of gases from the distillation of the second stage to the stage of condensation-absorption of gases from the distillation of the first stage and from the stage of condensation-absorption of gases from the distillation of the first stage in the synthesis zone, the evaporation of an aqueous solution of urea in several stages of heat exchange between the gases of distillation of the first stage and an aqueous solution of urea at the stage of preliminary evaporation, characterized in that the distillation of the water of urea on the first pressure hold a series of two zones, the first of which the distillation is carried out o adiabatically or heat input, and the second distillation is conducted while applying heat in a current of carbon dioxide.

2. The method according to p. 1, characterized in that the gases from the first zone of the first stage of distillation is directed to a stage of condensation-absorption of gases from the distillation of the first stage after their heat transfer in series with the urea melt in the second stage of its distillation and the aqueous solution of urea at the stage of preliminary evaporation, and the gases from the second zone lane is the second stage of distillation return in the first zone of the first stage of distillation and/or attached to the gases from the first zone of the first stage distillation before heat exchange with the melt of urea in the second stage of its distillation.

3. The method according to p. 1, characterized in that the gases from the first zone of the first stage distillation sent directly to the stage of condensation-absorption of gases from the distillation of the first stage, and the gases from the second zone of the first stage of distillation is directed to a stage of condensation-absorption of gases from the distillation of the first stage after their heat transfer in series with the urea melt in the second stage of its distillation and the aqueous solution of urea at the stage of preliminary evaporation.

4. The method according to p. 1, characterized in that the gases from the first zone of the first stage distillation sent directly to the stage of condensation-absorption of gases from the distillation of the first stage, and the gases from the second zone of the first stage of distillation is directed to a stage of condensation-absorption of gases from the distillation of the first stage after heat exchange with an aqueous solution of urea at the stage of preliminary evaporation.

5. Device for producing urea, includes a reactor for the synthesis of urea, the device with a supply of heat from an external source for the distillation of water urea obtained in the synthesis reactor at a first pressure, a device with a supply of heat for the distillation of water urea at a second pressure, the apparatus for evaporation by heating an aqueous urea solution obtained in the second stage distillation device is for condensation-absorption cooling gases of distillation both stages, the heat exchanger-recuperator for heat exchange between the gases of distillation of the first stage and an aqueous solution of urea, means for feeding ammonia and carbon dioxide in the reactor for the synthesis of urea, the urea melt from the synthesis reactor in a device for distillation of the first stage and from the device to the first distillation stage in a device for distillation of the second stage, an aqueous solution of urea from the device for distillation of the second stage of the heat exchanger-the heat exchanger and from the heat exchanger-the heat exchanger in the apparatus for subsequent evaporation, distillation gases from the device for distillation of the first stage of the heat exchanger-the heat exchanger and from the heat exchanger-recuperator in a device for condensation-absorption of gases the first stage distillation, distillation gases from the apparatus for distillation of the second stage in the device for condensation-absorption of gases from the distillation of the second step, a solution of ammonium salts of the device for condensation-absorption of gases from the distillation of the second stage in the device for condensation-absorption of gases from the distillation of the first stage and from the device for condensation-absorption of gases from the distillation of the first stage in the synthesis reactor, characterized in that the device for distilling the first stage consists of a column of the first distillation stage and film heat exchanger, and install the holding additional means for feeding the melt of urea from the column of the first distillation stage, in film and heat exchanger means for supplying carbon dioxide film heat exchanger.

6. Installation under item 5, characterized in that the means for feeding gases distilled from the device to the first distillation stage in a heat exchanger-a heat exchanger includes means for supplying gases distilled from the distillation columns of the first degree in the area of the heating device to a second distillation stage, means for feeding gases distilled from the film of the heat exchanger to the distillation column of the first stage and/or in the zone of the heating device to the second distillation stage and means for conducting gases from the distillation zone heating device for distillation of the second stage of the heat exchanger-recuperator.

7. Installation under item 5, characterized in that the means for feeding gases distilled from the device to the first distillation stage in a heat exchanger-a heat exchanger includes means for supplying gases distilled from the film heat exchanger in the heating zone of the device to the second distillation stage and from the zone of the heating device to the second distillation stage in the heat exchanger-recuperator, and the installation includes optional means for supplying gases distilled from the distillation columns of the first stage directly to the device for condensation-absorption of gases from the distillation of the first degree.

8. Installation under item 5, characterized in that the means for feeding gases distilled from the device for distillation of pervouchine in the heat exchanger-a heat exchanger includes means for supplying gases distilled from the film heat exchanger in the heat exchanger-recuperator, and the installation includes optional means for supplying gases distilled from the distillation columns of the first stage directly to the device for condensation-absorption of gases from the distillation of the first degree.



 

Same patents:

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 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 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: 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

The invention relates to the technology of complex processing of hydrocarbon fuel gases, such as methane and other natural gases, to obtain a synthesized substances

The invention relates to a method for joint production of ammonia and urea on the plant includes a reactor for the synthesis of ammonia synthesis reactor urea and the regeneration section of the urea

The invention relates to a method for producing urea by the interaction of ammonia with carbon dioxide in two reaction zones operating in parallel

The invention relates to equipment carrying out processes in gas-liquid environments and can be used for the synthesis of urea from ammonia and carbon dioxide at elevated temperatures and pressures

The invention relates to the synthesis of urea from ammonia and carbon dioxide

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 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

The invention relates to a method for joint production of ammonia and urea on the plant includes a reactor for the synthesis of ammonia synthesis reactor urea and the regeneration section of the urea

The invention relates to a method for producing urea by the interaction of ammonia with carbon dioxide in two reaction zones operating in parallel

The invention relates to the synthesis of urea from ammonia and carbon dioxide

The invention relates to improvements in the technology of production of urea from ammonia and carbon dioxide

The invention relates to a method for producing urea

The invention relates to the technology of production of urea from ammonia and carbon dioxide

The invention relates to the technology of production of urea

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

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