Method and apparatus for producing urea

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

 

The present invention relates in General to a method for producing urea from ammonia and carbon dioxide, interacting under a given high pressure in the corresponding section of the synthesis.

In particular, this invention relates to the aforementioned method, for which the product of the reaction between ammonia and carbon dioxide containing mainly an aqueous solution comprising urea, ammonium carbamate and ammonia, passes through a stage of extraction of high-pressure ammonium carbamate and ammonia, which return in section synthesis for reprocessing, while the aqueous urea solution is fed to the section extraction of urea, operating at a predetermined low pressure, to obtain a urea with a minimum number of possible residual ammonia and carbon dioxide.

More specifically, the present invention relates to the aforementioned method, by which the above-mentioned extraction of carbamate and ammonia includes the technological stage of decomposition of the carbamate and evaporation thus obtained with ammonia and carbon dioxide in the appropriate area of evaporation, preferably with a gaseous reagent (in particular, CO2), then re-condensing the above-mentioned ammonia and carbon dioxide in the appropriate area of condensation with obtaining ka is bamaca, the return section of the synthesis recycle, and where all the above mentioned stages, along with the reaction of the synthesis of urea, are carried out mainly under the same high pressure (for example, 135-175 bar), forming a loop, which in the field of technology called "high pressure" or "circuit synthesis under high pressure" (path e).

This invention relates also to an apparatus for implementing this method.

How to get urea for industrial installations, which are described above, is well known.

In addition, given the ever-increasing demand in the synthesis of urea, a well-known necessity of increasing the capacity of such plants as compared to the design capacity, on which these units were originally designed.

To this end, in this area the proposed methods, which provide technological stage of processing at medium pressure (10-40 bar) part containing the urea aqueous solution coming from the section of the synthesis, to extract the contained ammonium carbamate and ammonia.

In particular, this section processed at an average pressure includes a step of dissociation, followed by the stage of evaporation of an aqueous solution containing urea, ammonium carbamate and ammonia, using IP is one CO 2and the next stage of condensation thus obtained vapor (ammonia, CO2and water) with the addition of a source of ammonia and an aqueous solution of carbamate (carbonate), coming from the section of the extraction of urea at low pressure. Then an aqueous solution of carbamate obtained at the stage of condensation with an average pressure return circuit synthesis at high pressure (path e) for reprocessing.

This method is described, for example, in WO-A-02909323 in NL-A-8900152.

Despite the fact that these above-mentioned processes for the production of urea is at least partially provide the specified need, they discovered the disadvantages associated with the need to use additional quantities of the condensation of water for condensation of the original CO2used as the inert gas to evaporate from the solution at the stage of evaporation at the average pressure and the source of ammonia is added at the stage of condensation under medium pressure.

This additional use of the condensation of water adversely affects the yield of the reaction product in the synthesis of urea and, consequently, the efficiency and the energy consumption in this section, as well as on the efficiency and the power consumption section of the extraction of urea at low pressure.

The technical problem lay he is at the basis of the present invention, is the development and establishment of a method of producing urea discussed above type which eliminates the above disadvantages of the known prior art, the application of which can be provided with high production capacity of the plant designed for its implementation, and at the same time, efficiently and with low power consumption can be provided a high degree of conversion of carbon dioxide to obtain urea.

In accordance with the present invention this problem is solved in the proposed method of producing urea from ammonia and carbon dioxide, which includes stages/steps:

the supply of ammonia and carbon dioxide in the section of the synthesis of urea, operating at a predetermined high pressure,

the interaction of ammonia and carbon dioxide in the synthesis of obtaining an aqueous solution containing urea, ammonium carbamate and ammonia,

supply part of the above aqueous solution containing urea, ammonium carbamate and ammonia, in the processing section operating at a predetermined medium pressure to extract the contained ammonium carbamate and ammonia,

dissociation specified parts of an aqueous solution containing urea, ammonium carbamate and ammonia, in the section treated with obtaining an aqueous solution of urea and a vapor phase containing ammonia, carbon dioxide and water,

condensational vapor phase, containing ammonia, carbon dioxide and water, in the section treated with obtaining an aqueous solution of ammonium carbamate,

recirculation specified aqueous solution of ammonium carbamate in the section of the synthesis of urea,

feed the remaining part of the aqueous solution containing urea, ammonium carbamate and ammonia, in the apparatus for decomposition in section extraction of urea through the zone of evaporation, working essentially with said predetermined high pressure,

characterized in that it also involves the following stages:

feeding an aqueous solution of urea, the resulting dissociation in the processing section in the apparatus for the decomposition in section extraction of urea, operating at a predetermined low pressure,

decomposition of an aqueous solution of urea in an apparatus for the decomposition of the partition extraction of urea to produce a concentrated solution of urea and a second vapor phase containing ammonia, carbon dioxide and water,

condensing the second vapor phase in the condenser section of the extraction of urea, soobshayem with the specified apparatus for decomposition, to obtain the recirculating aqueous solution of ammonium carbamate.

In a preferred embodiment, the proposed method also includes technological stages:

supply of carbon dioxide in the condenser section of the extraction of urea,

condens the tion of carbon dioxide with the specified second vapor phase in the condenser section of the extraction of urea with getting recirculating aqueous solution of ammonium carbamate.

In this respect, particularly good results are obtained when applying carbon dioxide in quantities of 1 to 10 wt.% of the total number of source carbon dioxide, the condenser section of the extraction of urea.

The above aqueous solution containing urea, ammonium carbamate and ammonia is supplied to the processing section operating at medium pressure, is preferably from 10 to 50 wt.% specified aqueous solution containing urea, ammonium carbamate and ammonia obtained in the above section synthesis.

In addition, the indicated mean pressure in the processing section is preferably from 10 to 70 bar.

In accordance with another preferred embodiment of the present invention specified recirculating aqueous solution of ammonium carbamate, obtained in the condenser section of the extraction of urea at low pressure, serves on the stage of condensation of the vapor phase containing ammonia, carbon dioxide and water, in the above-mentioned processing section (usually aqueous solutions of carbamate obtained downstream from section synthesis installation for the production of urea return directly or indirectly in this section, and in this particular case we are talking about indirect recycling).

In the above stage condensing steam FA is s, containing ammonia, carbon dioxide and water, in the processing section preferably achieve a double effect.

Thanks to the method in accordance with the present invention it has been unexpectedly discovered the advantage consisting in that the amount of condensation water (in absolute value)required to return unreacted ammonia and carbon dioxide in the form of ammonium carbamate in section synthesis, significantly less than the amount of condensation water (in absolute value), which is required for such a return when using methods of the prior art, in which the processing section average pressure serves a source of carbon dioxide and a source of ammonia.

This is because at the same production capacity of the plant production of urea, ammonia and carbon dioxide to be returned to the section of the synthesis in the form of ammonium carbamate, in the application proposed in this invention method is much less than when using known methods of the prior art.

As a result of this substantially increases the yield of the reaction product in the synthesis of urea, as well as the total yield of the circuit e, which gives large advantages in terms of efficiency and energy consumption of the plant designed to carry out the proposed in the present the invention a method.

In accordance with another feature of the present invention, this technical problem is solved by the proposed apparatus for implementing the foregoing method, including the sections of the synthesis of urea under high pressure, comprising a reactor, a Stripping unit and the condenser section of the processing at medium pressure part of the urea solution obtained in section synthesis, including apparatus for dissociation and the capacitor, and the section of the extraction of urea at low pressure, comprising the apparatus for decomposing and the capacitor; and these sections are communicated with each other, and said reactor has an outlet of an aqueous solution containing urea, carbamate and ammonia, and this output includes the first line for submission of the above solution in the Stripping apparatus section synthesis and a second line for supplying the said solution in the apparatus for the dissociation of the section average pressure; setting differs in that it also includes a connecting pipe between the said apparatus for the dissociation of the processing section at the average pressure and apparatus for the decomposition of the partition extraction of urea at low pressure.

According to the present invention a plant for urea in accordance with the above method can be a completely new installation or an existing installation the internals, modified to increase its capacity.

In this latter embodiment, in accordance with another feature of the present invention, a method of reconstruction of a previously mounted (existing) installation of production of urea from ammonia and carbon dioxide containing section of the synthesis of urea under high pressure and partition extraction of urea at low pressure, comprising the apparatus for decomposing and condenser, and these sections are communicated with each other, characterized in that the carry out:

the mounting section of the processing at medium pressure part of the urea solution obtained in the specified section of the synthesis, including apparatus for dissociation and the capacitor, and this section of the processing at the average pressure communicates with the section of the synthesis of urea under high pressure and partition extraction of urea at low pressure, and

installation of connecting pipe between the said apparatus for the dissociation of the processing section at the average pressure and apparatus for the decomposition of the partition extraction of urea at low pressure.

Other characteristics and advantages of the proposed invention is a method of producing urea will be apparent from the following description of the preferred variants of its implementation with reference to the attached drawing, given not with a view to their limits, and only the purpose of disclosure, and on which:

On the accompanying drawing as an example implementation of the present invention schematically shows a plant for urea, which is proposed in the present invention method.

The drawing shows a plant for urea, generally designated by the number 10, on which the method in accordance with the present invention.

In accordance with the above method of producing urea ammonia N and carbon dioxide With served in the appropriate section 11 of the synthesis. In the example shown in the drawing, the section of the synthesis of urea includes one reactor R.

In particular, in accordance with this example ammonia N served in the reactor R through the condenser 12, and carbon dioxide, in turn, fed into the reactor R through the Stripping apparatus 13 and capacitor 12.

Section 11 synthesis of (reactor R), a capacitor 12, a Stripping device 13 together with the scrubber 14 (a more detailed description will be given below) mostly work at the same high pressure, thus forming a circuit synthesis at high pressure (path e) for carrying out the present invention method.

Ammonia and carbon dioxide react in the reactor R, or more precisely in section 11 synthesis at the above predetermined high pressure (comprising, for example, from 130 d is 170 bar) and at a predetermined high temperature (component, for example, from 160 to 200°C). In the reactor R obtain an aqueous solution containing urea, ammonium carbamate and ammonia.

An aqueous solution containing urea, ammonium carbamate and ammonia coming out of the reactor R, subjected to appropriate decompression on the merits in the usual way, for example, by means of the valve 15, and is fed to the processing section 16 of this aqueous solution, operating at a given average pressure of, for example, from 10 to 70 bar, preferably of 15 to 25 bar and even more preferably of 18 to 20 bar.

To extract the ammonium carbamate and ammonia in an aqueous solution containing urea, ammonium carbamate and ammonia, after appropriate pressure relief served in the device 17 for dissociation at an average pressure section 16 processing and subjected to dissociation to obtain an aqueous solution of urea and a vapor phase containing ammonia, carbon dioxide and water. In particular, in the apparatus 17 for dissociation of this part of the aqueous solution containing urea, ammonium carbamate and ammonia, are subjected to thermal dissociation.

Then thus obtained vapour phase containing ammonia, carbon dioxide and water, served in operating at medium pressure condenser 18 section 16 of the processing. In the condenser 18 will receive an aqueous solution of ammonium carbamate, which comes from the of condensator 18 and recycle in section 11 of the synthesis of urea (reactor R).

In the example shown in the drawing, an aqueous solution of carbamate coming from the condenser 18, operating at medium pressure, is subjected to appropriate compression on the merits in the usual way, for example, by a pump 19, and through the scrubber 14 and the capacitor 12, operating at high pressure, return to the reactor R section 11 synthesis of urea under high pressure. In accordance with another not represented the embodiment of the present invention at least part of the aqueous solution of carbamate coming from the condenser 18, operating at medium pressure, after appropriate compression is fed directly into the condenser 12, operating at high pressure, and then into the reactor R.

In accordance with the present invention a method of producing urea mainly involves the additional step of feeding the aqueous urea solution obtained by dissociation in the device 17 for dissociation at an average pressure section 16 of the processing apparatus 22 for decomposition section 21 extraction of urea, operating at a predetermined low pressure of, for example, from 1.5 to 9.5 bar, preferably of 3 to 5 bar.

With this purpose, the aqueous urea solution coming out of the device 17 for dissociation, is subjected to appropriate decompression on the merits in the usual way, for example, with SIP is by valve 20.

In particular, as shown in the preferred embodiment proposed in the present invention method in the drawing, an aqueous urea solution coming out of the device 17 for the dissociation of section 16 of the processing, is fed directly to the device 22 for decomposition section 21 extraction of urea.

In addition, also in accordance with the example in the drawing, the portion of the source of carbon dioxide With preferably and predominantly served in the capacitor 23 section 21 extraction of urea at low pressure.

With this purpose, this part of the original carbon dioxide sent into the condenser 23, is subjected to appropriate decompression on the merits in the usual way, for example, through a valve 30.

In the apparatus 22 for decomposition section 21 extraction of urea at low pressure aqueous urea solution coming from the device 17 for the dissociation of section 16 of the handle at an average pressure, is subjected to decomposition to produce a concentrated solution U of urea and second vapor phase containing ammonia, carbon dioxide and water.

A concentrated solution U of urea, for example, the concentration of the urea component is from 60 to 80 wt.%, exit from the apparatus 22 for decomposition section 21 extraction of urea in order to pass the final (essentially conventional and therefore not shown) processing stage, urea is the process of obtaining urea, for example, stage vacuum decay and granulation stage or granulation curing of the droplets of the sprayed molten urea thus obtained.

On the other hand, in accordance with the method according to the present invention, the second steam phase containing ammonia, carbon dioxide and water, which is obtained in the apparatus 22 for decomposition section 21 extraction of urea, served in the capacitor 23 in the same section 21 and preferably is subjected to condensation to obtain a recirculating aqueous solution of carbamate.

As shown in the example in figure 1, the second steam phase containing ammonia, carbon dioxide and water, is preferably subjected to condensation along with the original carbon dioxide, filed in the above-mentioned capacitor 23.

To ensure condensation, respectively, the second vapor phase and a source of carbon dioxide to obtain the ammonium carbamate in the capacitor 23 section 21 extraction of urea at low pressure is also served with the appropriate amount of an aqueous solution of carbamate (carbonate), the content of the condensation water which is from 40 to 80 wt.%.

The aqueous solution W carbamate (carbonate) usually comes from the section treated process condensate and(or) from the tank for ammonia water, essentially standard and not pre is presented in the drawing.

As shown in the example, recirculating aqueous solution of carbamate obtained in the condenser 23 section 21 extraction of urea at low pressure, in accordance with the present method preferably fed into the condenser 18, operating at medium pressure section 16 of the processing for absorption (condensation) vapor phase containing ammonia, carbon dioxide and water coming from the unit 17 for dissociation operating at medium pressure.

In this embodiment, is also provided stage compression recirculating aqueous solution of carbamate coming from the condenser 23 to the working pressure in the processing section 16 is essentially the usual way, for example, by a pump 24.

In accordance with no presents an alternative implementation of the method according to the present invention at the stage of condensation in the condenser 18 section 16 of the handle when the average pressure is provided by a double effect, in which the heat of condensation, instead dispersed in the coolant (usually cooling water), mainly used to further increase the concentration of the concentrated solution U of urea coming from the apparatus 22 for the decomposition of the partition extraction of urea at low pressure.

In this embodiment, the heat of condensation, which is formed during the condensation of PA the new phase, by indirect heat exchange (heat transfer through the wall) is transmitted to concentrated solution U of urea, providing decomposition and, consequently, the separation of parts of ammonium carbamate, ammonia and water, which are still present in this solution, and, thus, increasing the concentration of the contained urea.

The remaining aqueous solution containing urea, ammonium carbamate and ammonia coming out of the reactor R and is not supplied to the processing section 16 at an average pressure, passes through a stage of extraction of the ammonium carbamate and ammonia present in the solution in the high pressure circuit according to the present method.

In particular, the remaining portion of an aqueous solution containing urea, ammonium carbamate and ammonia coming out of the reactor R section 11 of synthesis, served in the Stripping apparatus operating at high pressure, where it is subjected to decomposition and evaporation source carbon dioxide C. Then the resulting ammonia and carbon dioxide re-condense in the condenser 12, operating at high pressure, to obtain ammonium carbamate and ammonium carbamate return to the reactor R section 11 of the synthesis of urea.

The condensation of ammonia and carbon dioxide coming from the Stripping apparatus 13, is carried out in the condenser 12, operating at high pressure, through the POG is osenia source of these gases ammonia N (liquid) and an aqueous solution of carbamate, coming after a corresponding compression of the capacitor 18 section 16 of the handle when the average pressure across the scrubber 14.

An aqueous solution containing urea, ammonium carbamate and ammonia obtained in the Stripping device 13, after the aforementioned stages of decomposition and evaporation with CO2put the appropriate decompression on the merits in the usual way, for example, with a valve 25, to the working pressure section 21 extraction of urea and served in the apparatus 22 for the decomposition of operating at low pressure in this section 21. Here the solution is subjected to decomposition with the above aqueous solution of urea coming from the device 17 for the dissociation of section 16 of the handle at an average pressure to obtain a concentrated solution U of urea and second vapor phase containing ammonia, carbon dioxide and water as described above.

Unreacted carbon dioxide and ammonia and water in the vapor phase present in section 11 of the synthesis of urea, or more precisely in the reactor R, is removed from the reactor and fed into the scrubber 14, operating at high pressure. These pairs are usually also contain inert gases (e.g. air)present in the original carbon dioxide C.

In the scrubber 14 of the above pairs is subjected to wet treatment (washing) with an aqueous solution of carbamate coming after sootvetstvujushchie from the condenser 18 section 16 of the handle at an average pressure, to extract present in the carbon dioxide and ammonia and separation of inert gases. Then selected so inert gases released into the atmosphere essentially the usual way, moreover, providing appropriate discharge pressure of these gases, for example, with a valve 26. Alternatively, these inert gases can be returned to other nodes (not shown). On the other hand, carbon dioxide and ammonia, absorbed in an aqueous solution of carbamate coming from the condenser 18, return through the condenser 12, operating at high pressure, in section 11 of the synthesis of urea, or more precisely in the reactor R.

In the application proposed in this invention method is particularly good results were obtained when applying a source of carbon dioxide in quantities of 1 to 5 wt.%, even more preferably 2 to 3 wt.% of the total number of source carbon dioxide supplied to the plant 10, the capacitor 23 section 21 extraction of urea at low pressure.

Next, an aqueous solution containing urea, ammonium carbamate and ammonia is directed to section 16 of the handle when the average pressure is preferably from 10 to 50 wt.%, even more preferably from 10 to 25 wt.% aqueous solution coming from section 11 of the synthesis of urea.

Described constructi the major features of the system 10 is received by the synthesis of urea from ammonia and carbon dioxide in accordance with the method according to the present invention will hereinafter be described in detail with reference to the drawing.

In accordance with the present invention, the system 10 includes section 11 synthesis of urea under high pressure section 16 of the processing at the average pressure and the section 21 extraction of urea at low pressure, communicating with each other.

Section 16 processing mainly includes apparatus 17 for dissociation operating at medium pressure, and operating at medium pressure condenser 18, communicating with each other. In turn, section 21 extraction of urea includes apparatus 22 for the decomposition of operating at low pressure, and operating at low pressure condenser 23, communicating with each other.

The installation 10 includes the appropriate pipelines to supply reagents, carbon dioxide and ammonia N, and, in addition, an aqueous solution W carbamate (carbonate)containing condensation water, as well as connecting lines between the different sections and corresponding apparatus, schematically shown in the drawing various lines indicating the flow.

In particular, the system 10 for direct communication, respectively, between the section 11 of the synthesis of urea and apparatus 17 for the dissociation of section 16 of the handle at an average pressure, and between this apparatus and the apparatus 22 for decomposition section 21 extraction of urea at low pressure mainly provided by soy is internee pipes 28 and 29.

Moreover, in accordance with the preferred embodiment of the present invention, shown in the drawing, for supplying a source of carbon dioxide in the condenser 23 section 21 extraction of urea at low pressure is also provided a pipe 27.

In accordance with alternative, non-represented variant, the installation 10 according to the present invention for obtaining the above-described double-effect capacitor 18, operating at medium pressure, includes a standard bundle of tubes, inside of which, i.e. in-line area, is a concentrated solution U of urea coming from the apparatus 22 for the decomposition of operating at low pressure, and from the outside, i.e. in the annular zone is a vapor phase containing ammonia, carbon dioxide and water coming from the unit 17 for dissociation operating at medium pressure and recirculating aqueous solution of carbamate coming from the condenser, operating at low pressure.

From the previous description it is obvious that the method of producing urea in accordance with this invention solves the technical problem and provides numerous advantages, the first of which is that in the high pressure circuit receive high overall yield and, in particular, in section synthesis is Icewine, constituting, for example, from 58 to 62 wt.%, regardless of the required production capacity of the plant designed for its implementation.

Therefore, the claimed method is also particularly advantageous for installations with high power, for example, for the production of from 3000 to 4500 metric tons of urea per day.

Another advantage is that thanks to the present invention and, in particular, a high product yield can reduce the power consumption in the circuit synthesis at high pressure and in section extraction of urea at low pressure compared with the methods in accordance with the prior art. This implies that for the same power consumption and size of the devices that make up a plant for urea, the method in accordance with the present invention provides operation of this unit with higher performance than that which is possible with the use of methods in accordance with the prior art. In other words, with the same production capacity of the plant intended for carrying out the present invention method, smaller and, therefore, it costs less and operational costs are less than needed to install to get the same power when using known what the key ways of technology.

Moreover, the introduction of this method in action is very simple and reliable and does not require large capital investments.

The above-mentioned advantages, mainly related to the fact that due to the studies, it has been unexpectedly found that if the aqueous urea solution obtained by dissociation in section 16 of the handle at an average pressure, subjected to decomposition at low pressure, the amount (in absolute value) of the condensation water contained in the aqueous solution W carbamate (carbonate), which is required for this condensation to obtain ammonium carbamate, significantly less than the amount of condensation water is required when using methods in accordance with the prior art.

Provided that this condensation water with ammonium carbamate return section of the synthesis of urea, and assuming that the water in the synthesis of urea is the reaction product and therefore has a negative impact on the transformation of the reactants, the regulation to significantly reduce the amount of condensation water is mainly led to a corresponding increase in product yield in comparison with the known methods of the prior art.

In particular, known methods, in contrast to the present invention, be sure to include the section 16 of the handle at an average pressure stage evaporation source carbon dioxide aqueous solution of urea, previously obtained in this section by thermal dissociation, and the stage of condensation by adding a source of ammonia. Thus, in order to ensure effective and complete condensation of such quantities of source carbon dioxide and ammonia, which is injected into the processing section average pressure, to obtain ammonium carbamate, you must submit the condensation water in the extraction section of urea at low pressure in much larger quantities (in absolute value)than is required using the proposed in the present invention method.

For example, it was found that under the same operating conditions above the amount of the condensation water contained in the aqueous solution W carbamate (carbonate), using the proposed in the present invention method, 10-25 wt.% less than when using known methods, with a corresponding increase in product yield in the synthesis of urea under high pressure by 2-3%.

Among the many advantages derived from the present invention, it is important to mention the possibility of increasing the production capacity of existing plant production of urea from ammonia and carbon dioxide compared with a design capacity that these units were originally designed, and simple, effective and adinam way without any associated negative impact on overall product yield, operating costs and energy consumption for the current installation. There is also the possibility of a significant increase in power compared with the estimated capacity of the existing installation, for example, by 30-50%.

In accordance with a preferred embodiment of the present invention, shown in the drawing, the system 10 receiving urea can be mounted through reconstruction (modernization) of existing facility of this type to obtain urea from ammonia and carbon dioxide containing section 11 synthesis of urea under high pressure and section 21 extraction of urea at low pressure, comprising the apparatus 22 for decomposition and the capacitor 23; these sections 11, 21 are communicated with each other; the method characterized in that it further includes the stages of establishment (mounting):

section 16 of the handle at an average pressure part of the urea solution obtained in the specified section 11 of the synthesis, including the device 17 for dissociation and the capacitor 18, the specified section 16 of the handle at an average pressure, communicating with the specified section of the synthesis of urea under high pressure and partition extraction of urea at low pressure, respectively, 11,21;

direct connecting pipe 29 between the specified AP is the Arat 17 for the dissociation of section 16 of the processing at the average pressure and the apparatus 22 section 21 extraction of urea at low pressure.

The proposed method preferably provides an additional stage of installation of the pipe 27 for supplying a source of carbon dioxide With the above-mentioned capacitor 23 section 21 extraction of urea at low pressure.

Specialist in the art will, of course, may make numerous changes and modifications in the above described method for the production of urea to meet the specific and depending on the circumstances of the requirements that are included in the scope of protection of the present invention defined in the following claims.

1. A method of producing urea from ammonia and carbon dioxide, comprising the steps:
the supply of ammonia and carbon dioxide in the section of the synthesis of urea, operating at a predetermined high pressure,
the interaction of ammonia and carbon dioxide in the synthesis of obtaining an aqueous solution containing urea, ammonium carbamate and ammonia,
supply part of the above aqueous solution containing urea, ammonium carbamate and ammonia, in the processing section operating at a predetermined medium pressure to extract the contained ammonium carbamate and ammonia,
dissociation specified parts of an aqueous solution containing urea, ammonium carbamate and ammonia, in the section treated with obtaining an aqueous solution of urea and a vapor phase containing Ammi is to, carbon dioxide and water,
condensation specified vapor phase containing ammonia, carbon dioxide and water, in the section treated with obtaining an aqueous solution of ammonium carbamate,
recirculation specified aqueous solution of ammonium carbamate in the section of the synthesis of urea,
feed the remaining part of the aqueous solution containing urea, ammonium carbamate and ammonia, in the apparatus for decomposition in section extraction of urea through the zone of evaporation, working essentially with said predetermined high pressure,
characterized in that it also involves the following stages:
feeding an aqueous solution of urea, the resulting dissociation in the processing section in the apparatus for the decomposition in section extraction of urea, operating at a predetermined low pressure,
decomposition of an aqueous solution of urea in an apparatus for the decomposition of the partition extraction of urea to produce a concentrated solution of urea and a second vapor phase containing ammonia, carbon dioxide and water,
condensing the second vapor phase in the condenser section of the extraction of urea, soobshayem with the specified apparatus for decomposition, to obtain the recirculating aqueous solution of ammonium carbamate.

2. The method according to claim 1, characterized in that it comprises the stage of:
supply of carbon dioxide in the condenser section of the extraction of urea, conden the emission of carbon dioxide with the specified second vapor phase in the condenser section of the extraction of urea with getting recirculating aqueous solution of ammonium carbamate.

3. The method according to claim 2, characterized in that serves the carbon dioxide in the condenser section of the extraction of urea in an amount of 1 to 10 wt.% of the total number of source carbon dioxide.

4. The method according to claim 1, characterized in that a specified part of an aqueous solution containing urea, ammonium carbamate and ammonia is supplied to the processing section operating at medium pressure ranges from 10 to 50 wt.% specified aqueous solution containing urea, ammonium carbamate and ammonia obtained in section synthesis.

5. The method according to claim 1, characterized in that the average pressure of the processing section is from 10 to 70 bar.

6. The method according to claim 1, characterized in that the recirculating aqueous solution of ammonium carbamate, obtained in the condenser section of the extraction of urea at low pressure, serves on the specified stage of condensation of the vapor phase containing ammonia, carbon dioxide and water, in the processing section.

7. The method according to claim 1, characterized in that the stage of condensation of the vapor phase containing ammonia, carbon dioxide and water, in the processing section provides a double effect.

8. Installation (10) receipt of urea from ammonia and carbon dioxide, containing
section (11) synthesis of urea under high pressure, comprising a reactor, a Stripping apparatus (13) and the condenser (12),
section (16) of the processing at medium pressure, comprising the apparatus (17) for dissociation and the condenser (18),
section (21) extraction of urea at low pressure, comprising the apparatus (22) for the decomposition and the condenser (23),
moreover, section (11, 16, 21) communicate with each other, and
said reactor has an outlet of an aqueous solution containing urea, carbamate and ammonia, and this output includes a first line for supplying the said solution in the Stripping apparatus (13) section (11) synthesis and a second line for supplying the said solution in the apparatus (17) for the dissociation of the section average pressure and
the installation further comprises a connecting pipe (29) for feeding the urea solution obtained in the apparatus (17) for dissociation, the device (22) for the decomposition section (21) extraction of urea at low pressure.

9. Installation (10) according to claim 8, characterized in that it further includes a pipe (27) for supplying a source of carbon dioxide in the condenser (23) section (21) extraction of urea at low pressure.

10. Installation (10) according to claim 8, characterized in that the condenser (18) of section (16) of the handle at an average pressure contains a bundle of tubes connected to each other, line the area with a concentrated urea solution leaving the apparatus (22) for the decomposition section (21) extraction of urea at low pressure, and annular zone with steam phase containing ammonia, carbon dioxide and water, coming out of the device (17) for the dissociation of section (16) processing at the average pressure and recirculating aqueous solution of carbamate leaving the condenser (23) section (21) extraction of urea at low pressure.

11. The method of reconstruction of the previously installed plant production of urea from ammonia and carbon dioxide, contains the partition (11) synthesis of urea under high pressure section (21) extraction of urea at low pressure, comprising the apparatus (22) for the decomposition and the condenser (23), and these sections (11, 21) communicate with each other, characterized in that exercise:
the mounting section (16) processing at medium pressure part of the urea solution obtained in the specified section (11) of the synthesis, including the device (17) for dissociation and the condenser (18), and this section (16) of the handle when the average pressure is communicated with section (11) synthesis of urea under high pressure section (21) extraction of urea at low pressure and
installation of connecting pipe (29) between the specified device (17) for the dissociation of section (16) processing at the average pressure and the apparatus (22) for the decomposition section (21) extraction of urea at low pressure.

12. The method according to claim 11, characterized in that it includes the installation of the pipeline (27) for supplying a source of carbon dioxide in the specified capacitor (23) section (21) izvlecheny the urea at low pressure.



 

Same patents:

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: process engineering.

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

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

101 cl, 2 ex, 4 tbl, 14 dwg

FIELD: chemistry.

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

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

14 cl, 4 dwg

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

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

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

11 cl, 2 ex, 2 dwg

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

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

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

12 cl, 2 dwg

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

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

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

3 cl, 3 dwg

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

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

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

8 cl, 3 ex, 3 dwg

FIELD: 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 chemical technology and chemical machine building, namely to reactors of gaseous chlorination of natural gas (methane) and can be used in production of chlormethanes. Reactor for natural gas chlorination contains body (1), cover (2), bottom (3), socket for supply of reagents (4), socket for output of reaction products (5), located in lower part of the reactor body, and internal cup (6) placed coaxially with the body, cup bottom being matched with reactor bottom, in the centre of the cup placed is socket for supply of reagents. Through socket for supply of reagents into the reactor introduced is mixer of reagents consisting of two tubes placed coaxially with the mixer nozzle (7). In claimed construction process of natural gas chlorination is carried out in adiabatic conditions. Products of chlorination, located in circular cavity of the reactor, thermostatically control reactor cup (6) ensuring chlorination process stability. Reaction heat is removed with reaction gases, output through the socket (5) in lower part of the reactor.

EFFECT: prevention of methylene chloride and chloroform return into chlorination zone due to absence of internal recycle of reaction gases, which increases process selectivity and reduces formation of ozone-depleting carbon tetrachloride.

2 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: present invention relates to versions of a method of stabilising the hydroformylation process and a device for realising the said method. One version of the method involves reaction of one or more reagents, carbon monoxide and hydrogen in the presence of a hydroformylation catalyst to obtain an exhaust gas stream and a reaction product stream which contains one or more products, in which the method described above is realised at such partial pressure of carbon monoxide that, the rate of reaction increases when partial pressure of carbon monoxide falls, and falls when partial pressure of carbon monoxide increases; and in which the following steps of the process for stabilising the rate of reaction, total pressure, speed of the exhaust gas stream, reaction temperature or combinations thereof are carried out, process steps including at least one of the following process control schemata, selected from: Scheme A: (a1) setting a given total pressure; (a2) determination of total pressure and determination of the difference between the measured total pressure and the given total pressure; and (a3) based on the pressure difference measured at step (a2), manipulation of the stream of incoming gas which contains carbon monoxide in order to balance the measured total pressure to virtually the given total pressure; and Scheme B: (b1) setting a given speed of the exhaust gas stream; (b2) determination of the speed of the exhaust gas stream and determination of the difference between the measured speed of the exhaust gas stream and the given speed of the exhaust gas stream; and (b3) manipulation of the speed of incoming gas which contains carbon monoxide based on the difference in the speed of the exhaust gas stream measured at step (b2) in order to equalise the determined speed of the exhaust gas stream virtually with the given speed of the exhaust gas stream.

EFFECT: design of an efficient method of stabilising the hydroformylation process.

26 cl, 2 tbl, 20 dwg, 7 ex

FIELD: chemistry.

SUBSTANCE: present invention relates to the method of producing dichloropropanols 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol through hydrochlorination of glycerine and/or monochloropropanediols by gaseous hydrogen chloride with carboxylic acid catalysis. Hydrochlorination is carried out at least in a single continuous reaction zone at reaction temperature 70-140°C and continuous removal of reaction water by distillation at low pressure. The liquid raw material contains at least 50 wt % glycerine and/or monochloropropanediols. The invention also pertains to versions of the apparatus for realising the method of producing dichloropropanols.

EFFECT: target products with high output and high selectivity of the reaction system.

16 cl, 4 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: apparatus for carrying out gas-phase catalytic chemical reaction of obtaining HCN contains catalyst/current-collector 1, located coaxially inside reactor 2 and having in essence circular transverse section. Catalyst/current-collector 1 is surrounded by non-electroconducting cylinder. Catalyst/current-collector 1 is inductionally heated by means of alternating magnetic field, generated by surrounding it induction coil 3, to temperature sufficient for carrying out chemical reaction. Intensity of energy release by induction coil 3 is measured along length of cylindrical catalyst/current-collector 1. Apparatus can be additionally equipped with gas-proof cylinder for gas flow in axial direction through catalyst/current-collector 1, or gas-permeable cylinder for gas flow in radial direction through catalyst/current-collector 1.

EFFECT: increase of efficient length of conducting tract in object from metal of platinum group; minimisation of temperature fluctuations in catalyst and minimisation of flow changes in it; reduction of capital investment and production expenditures.

25 cl, 32 ex, 8 dwg, 4 tbl

FIELD: machine building; units for chemical interaction of gas mixtures.

SUBSTANCE: piston-free machine consists of housing with the cylinder chamber, floating piston, and air bleed holes in the side wall of the housing. Cylinder chamber houses mutually connected movable covers with inlet and outlet holes aimed to form a bypass for supply of the mixture and discharge of gas with changed parameters. Floating piston is made as a differential piston. Floating piston and movable covers are made so that to provide counter-phase balanced movement of the piston and mutually connected movable covers in the housing. Floating piston, mutually connected movable covers, and housing form two cavities. Connection of mutually connected covers is located outside or inside the cylinder chamber.

EFFECT: simplification of free-piston machine design; enhancing the machine work efficiency; reduction of main parts weight.

5 cl, 2 dwg

FIELD: machine building; unit for chemical interaction of gas mixtures.

SUBSTANCE: piston-free machine for chemical interaction of gas mixtures consists of housing with the cylinder chamber, floating piston, and air bleed holes located in the side wall of the housing. Cylinder chamber houses mutually connected movable covers with inlet and outlet holes aimed to form a bypass for supply of the mixture and discharge of the gas with changed parameters. Floating piston is made as a differential piston. Floating piston and movable covers are made so that to provide counter-phase balanced movement of the piston and mutually connected movable covers in the housing. Floating piston, mutually connected movable covers, and housing form three cavities. Connection of mutually connected covers is located outside or inside the cylinder chamber.

EFFECT: simplification of free-piston machine design; enhancing the machine work efficiency; reduction of main parts weight; reduction of vibration during operation.

5 cl, 2 dwg

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

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

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

11 cl, 2 ex, 2 dwg

FIELD: chemical industry; apparatuses for production of the chlorinated allyl.

SUBSTANCE: the invention presents the reactor for production of the chlorinated allyl intended for realization of the method of production of the chlorinated allyl by the direct gaseous phase chlorination of the propylene. The reactor includes the closed circuit of circulation of the reaction gases, the devices of injection of the source propylene and chlorine, the device of the forced circulation of the part of the reaction gases and the device of withdrawal of the other part of the reaction gases. At that the closed circuit of the reaction gases circulation forms the jet pump, which includes in series connected the reception chamber, the mixing chamber and the diffuser, and the pipe of the circulation circuit connecting the outlet of the diffuser with the appropriate inlet of the reception chamber of the injector and acting as the main reaction zone of the ideal displacement with the presence time of 0.7-0.9 s, in which the scatter of the temperatures does not exceed ±10°С. The reception chamber contains the nozzles used as the devices for injection of the source propylene and chlorine. The jet pump ensures fulfillment of the concerted functions: introduction of the streams of the source propylene and chlorine, which are the working injecting streams; the forced circulation pump with the repetition factor of 5-10 of the reaction gases stream, which is the injected stream; the high-velocity mixer and the preheater of the source reactants in the mixing chamber due to the strong turbulence during (0.01-0.04)s, which is formed by the combination of the nozzles of the injected gases at the arrangement of the nozzle/ nozzles of the chlorine coaxially to the main nozzle of the propylene arranged on the shaft of the mixing chamber. The technical result of the invention is, that the presented design of the reactor allows to increase the selectivity of the process of production of the chlorinated allyl.

EFFECT: the invention provides, that the presented design of the reactor allows to increase the selectivity of the process of production of the chlorinated allyl.

1 ex, 1 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

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