CO and H2 co-production device of synthetic ammonia system

Abstract

The utility model discloses a device for co-producing CO and H2 in a synthetic ammonia system. Comprising a coal gasification unit, a synthesis gas outlet of the coal gasification unit is connected with a heat recovery unit, a shallow shift gas pipeline in the heat recovery unit is connected with a first low-temperature methanol washing unit, and a shallow shift purified gas outlet of the first low-temperature methanol washing unit is respectively connected with a methanol synthesis system and a CO purification part. A converted gas pipeline in the heat recovery unit is connected with a second low-temperature methanol washing unit, and a converted purified gas outlet of the second low-temperature methanol washing unit is connected with a synthetic ammonia system and an H2 purification part respectively; according to the utility model, on the basis of the existing ammonia synthesis system, the existing ammonia synthesis system is coupled with cryogenic separation and pressure swing adsorption technologies to prepare CO and H2, so that the yield of methanol, synthesis ammonia, CO and H2 is flexibly adjusted according to the market price, and the characteristic of improving the anti-risk capability of an enterprise is achieved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to coal chemical technology field, concretely is a kind of synthetic ammonia system co-production CO and H2's device. BACKGROUND

[0002] Coal is basic energy and important industrial raw material, with coal as raw material, synthetic gas is prepared by gasification process, and then synthetic gas extends to downstream, and other chemical products are produced, which is the main route of current coal extending to chemical field.CO and H2 as the main component of synthetic gas can be used for synthesizing methanol after mixing in a certain proportion, or can be used as the synthesis raw material of other chemical products or directly sold as product after separation.The above process route is relatively mature, when the price of synthetic gas and methanol is low, enterprise will be in loss state, cause the risk resistance of enterprise is weak, based on this, how to improve the risk resistance of enterprise under the premise of using synthetic ammonia system, then become the technical problem to be solved. CONTENT OF UTILITY MODEL

[0003] In order to make up for the above insufficient, the utility model provides a kind of synthetic ammonia system co-production CO and H2's device to solve the technical problems existing in prior art.

[0004] The technical scheme that the utility model solves its technical problems is as follows:

[0005] A kind of synthetic ammonia system co-production CO and H2's device, the device includes coal gasification unit, the synthetic gas outlet of coal gasification unit is connected with heat recovery unit, shallow conversion gas pipeline in the heat recovery unit is connected with first low temperature methanol washing unit, the shallow conversion purified gas outlet of first low temperature methanol washing unit is connected with methanol synthesis system and CO purification part respectively, conversion gas pipeline in the heat recovery unit is connected with second low temperature methanol washing unit, the conversion purified gas outlet of second low temperature methanol washing unit is connected with synthetic ammonia system and H2 purification part respectively.

[0006] The utility model has the advantages that: the utility model is based on existing synthetic ammonia system, make it and deep cooling separation and pressure swing adsorption technology are coupled for preparing CO and H2, so as to reach the yield of methanol, synthetic ammonia, CO and H2 is flexibly adjusted according to market price, to reach the characteristics of improving the risk resistance of enterprise.

[0007] Preferably, the CO purification part at least includes temperature swing adsorption unit, the import of temperature swing adsorption unit is connected with shallow conversion purified gas outlet, the gas phase outlet of temperature swing adsorption unit is connected with the import of deep cooling separation unit, and the product gas outlet of deep cooling separation unit is connected with CO product gas storage tank.

[0008] Preferably, the H2 purification unit comprises a first pressure swing adsorption unit, the gas inlets of the first pressure swing adsorption unit are connected with the shift purified gas outlet of the second low-temperature methanol washing unit and the hydrogen-rich gas outlet of the cryogenic separation unit respectively, and the product gas outlet of the first pressure swing adsorption unit is connected with an H2 product gas storage tank.

[0009] Preferably, the H2 purification unit further comprises a first circulating compressor, the inlets of the first circulating compressor are connected with the desorption tail gas outlet of the first pressure swing adsorption unit and the flash tail gas outlet of the cryogenic separation unit respectively, the outlet of the first circulating compressor is connected with a membrane separation unit, and the permeation gas outlet of the membrane separation unit is connected with the gas inlet of the first pressure swing adsorption unit through a second circulating compressor.

[0010] Preferably, the CO purification unit further comprises a second pressure swing adsorption unit, the inlets of the second pressure swing adsorption unit are connected with the methane-rich tail gas outlet of the cryogenic separation unit, the nitrogen-rich tail gas outlet of the cryogenic separation unit and the non-permeation gas outlet of the membrane separation unit respectively, and the product gas outlet of the second pressure swing adsorption unit is connected with a CO product gas storage tank.

[0011] Preferably, the displacement tail gas outlet of the second pressure swing adsorption unit is connected with the regeneration gas inlet of the temperature swing pressure swing adsorption unit.

[0012] Preferably, the regeneration gas outlet of the temperature swing pressure swing adsorption unit is connected with a combustion flare.

[0013] The device for co-producing CO and H2 by using an existing synthetic ammonia system is prepared according to the technical scheme, deep cooling separation, pressure swing adsorption technology and membrane separation technology are coupled on the existing coal-to-synthetic ammonia system, thereby a gas separation scheme for co-producing high-purity CO and H2 on the coal-to-synthetic ammonia system is provided, and effective components in tail gas of the deep cooling separation and the PSA hydrogen extraction device can be fully recovered, which not only enhances the ability of the enterprise to flexibly adjust downstream products, but also effectively reduces the consumption of raw materials; specifically, the crude coal gas is prepared into shallow-shift synthesis gas through shift, and after CO2 and other gases are removed by the first low-temperature methanol washing unit, the crude coal gas can be used as a main raw material gas source of CO and H2; meanwhile, by combining the membrane separation and the pressure swing adsorption technology, CO and H2 in the nitrogen-rich gas, the methane-rich gas, the flash gas generated by the deep cooling separation unit and the desorption tail gas generated by the first pressure swing adsorption unit can be maximally recovered, thereby the consumption of raw materials and the production cost are reduced; further, the displacement tail gas of the second pressure swing adsorption unit is used as the regeneration gas of the temperature swing pressure swing adsorption unit, which can effectively reduce or eliminate the need to introduce regeneration nitrogen from outside the boundary, so that the consumption of utilities is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained based on these drawings without creative labor.

[0015] Figure 1 The flowchart of the present application.

[0016] In the figure: 1, coal gasification unit; 2, displacement tail gas outlet; 3, heat recovery unit; 4, first low-temperature methanol washing unit; 5, methanol synthesis system; 6, second low-temperature methanol washing unit; 7, synthetic ammonia system; 8, temperature swing adsorption unit; 9, cryogenic separation unit; 10, CO product gas storage tank; 11, first pressure swing adsorption unit; 12, H2 product gas storage tank; 13, first circulating compressor; 14, membrane separation unit; 15, second circulating compressor; 16, second pressure swing adsorption unit; 17, combustion torch; 18, hydrogen-rich gas outlet; 19, flash tail gas outlet; 20, methane-rich tail gas outlet; 21, nitrogen-rich tail gas outlet; 22, permeation gas outlet; 23, non-permeation gas outlet; 24, desorption tail gas outlet. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0018] The following will be described in combination with the drawings Figure 1Further detailed description of the present application, the utility model relates to a kind of device for the co-production of CO and H2 of synthetic ammonia system, the device includes coal gasification unit 1, the syngas outlet of coal gasification unit 1 is connected with heat recovery unit 3, shallow shift gas pipeline in the heat recovery unit 3 is connected with first low temperature methanol washing unit 4, the shallow shift purification gas outlet of first low temperature methanol washing unit 4 is connected with methanol synthesis system 5 and CO purification part respectively, shift gas pipeline in the heat recovery unit 3 is connected with second low temperature methanol washing unit 6, the shift purification gas outlet of second low temperature methanol washing unit 6 is connected with synthetic ammonia system 7 and H2 purification part respectively.The utility model is further extension to the existing synthetic ammonia system, it not only can prepare traditional methanol and synthetic ammonia, also can be coupled with cryogenic separation and pressure swing adsorption technology for preparing CO and H2, in actual production, the yield of relevant product can be adjusted by adjusting the gas intake, to achieve the characteristics of flexible adjustment of product according to market situation, to achieve the purpose of improving the risk resistance of enterprise.

[0019] Further, the CO purification part at least includes temperature swing adsorption unit 8, the inlet of temperature swing adsorption unit 8 is connected with the shallow shift purification gas outlet, the gas phase outlet of temperature swing adsorption unit 8 is connected with the inlet of cryogenic separation unit 9, and the product gas outlet of cryogenic separation unit 9 is connected with CO product gas storage tank 10.The utility model can be used for preparing high-purity CO product gas by setting temperature swing adsorption unit 8 and cryogenic separation unit 9, and CO, as a carbonylation raw material, is also widely used in chemical industry, which can be used for synthesizing important chemical products such as methanol, acetic acid, ethanol and ethylene glycol;It is also an important reducing agent in the industry of metallurgy, coking and ironmaking.

[0020] Further, the H2 purification part includes first pressure swing adsorption unit 11, the gas inlet of first pressure swing adsorption unit 11 is connected with the shift purification gas outlet of second low temperature methanol washing unit 6 and the hydrogen-rich gas outlet 18 of cryogenic separation unit 9 respectively, and the product gas outlet of first pressure swing adsorption unit 11 is connected with H2 product gas storage tank 12.Through the above setting, the characteristics of producing high-purity H2 product gas can be realized.

[0021] Further, the H2 purification part further includes first circulating compressor 13, the inlet of first circulating compressor 13 is connected with the desorption tail gas outlet 24 of first pressure swing adsorption unit 11 and the flash tail gas outlet 19 of cryogenic separation unit 9 respectively, the outlet of first circulating compressor 13 is connected with membrane separation unit 14, and the permeation gas outlet 22 of membrane separation unit 14 is connected with the gas inlet of first pressure swing adsorption unit 11 by second circulating compressor 15.The utility model utilizes the above device to recycle and process the desorption tail gas from desorption tail gas outlet 24 and the flash tail gas from flash tail gas outlet 19, to realize the characteristics of improving the yield of H2 product gas, to achieve the characteristics of environmental protection and energy saving and cost reduction.

[0022] Further, the CO purification part further comprises a second pressure swing adsorption unit 16, the inlet of the second pressure swing adsorption unit 16 is connected with the methane-rich tail gas outlet 20 of the cryogenic separation unit 9, the nitrogen-rich tail gas outlet 21 of the cryogenic separation unit 9 and the non-permeation gas outlet 23 of the membrane separation unit 14 respectively; the product gas outlet of the second pressure swing adsorption unit 16 is connected with the CO product gas storage tank 10. Through the above setting, the methane-rich tail gas from the methane-rich tail gas outlet 20, the nitrogen-rich tail gas from the nitrogen-rich tail gas outlet 21 and the non-permeation gas from the non-permeation gas outlet 23 can be recovered and processed, so as to improve the yield of the CO product gas, and achieve the characteristics of environmental protection, energy saving and cost reduction.

[0023] Further, the displacement tail gas outlet 2 of the second pressure swing adsorption unit 16 is connected with the regeneration gas inlet of the temperature swing pressure swing adsorption unit 8.

[0024] Further, the regeneration gas outlet of the temperature swing pressure swing adsorption unit 8 is connected with the combustion torch 17.

[0025] The specific working process of the utility model is as follows: high pressure pure oxygen and coal enter the coal gasification unit 1 together, and after incomplete combustion in the gasifier, the crude synthesis gas mainly composed of H2, CO, CO2 and H2O is obtained, the coal gasification unit 1 is the conventional equipment in the field, which includes but is not limited to coal mill, gasifier, cyclone separator, scrubbing tower and other equipment, and can be directly purchased in the market, and since it is not the focus of the technical solution, the structure is not described in detail; the aforementioned crude synthesis gas is divided into two streams to enter the heat recovery unit, one stream of crude synthesis gas is sequentially sent to the ammonia washing tower after adiabatic shift, isothermal shift and heat recovery, and after removing ammonia in the synthesis gas, the crude synthesis gas is sent into the second low-temperature methanol washing unit 6 as shift gas; the other stream of crude synthesis gas is sent to the ammonia washing tower after adiabatic shift and heat recovery, and after removing ammonia in the synthesis gas, the crude synthesis gas is sent to the first low-temperature methanol washing unit 4 as shallow shift gas; the heat recovery unit includes but is not limited to adiabatic shift furnace, isothermal shift furnace, waste heat boiler, ammonia washing tower and other equipment. Can be directly purchased in the market, and since it is not the focus of the technical solution, the structure is not described in detail; the aforementioned shift gas enters the shift gas washing tower in the second low-temperature methanol washing unit 6 for washing and purification, and the shift gas purification gas is obtained; the main component of the shift gas purification gas is H2, the H2 purity is more than 95%, and the pressure is 5-6 MPa (G); the shift gas purification gas is divided into two streams, one stream is sent to the subsequent synthetic ammonia system 7 for producing synthetic ammonia, and the other stream is sent to the first pressure swing adsorption unit 11; the shallow shift gas purification gas is obtained after the aforementioned shallow shift gas is sent to the shallow shift gas washing tower in the first low-temperature methanol washing unit 4 for washing and purification, the pressure is about 5-6 MPa (G), the H2 purity is 50%-70%, the CO purity is 20%-40%, and a small amount of N2, CH4 and other inert gases are contained; the shallow shift gas purification gas is divided into two streams, one stream is sent to the methanol synthesis system 5 as methanol synthesis gas, and the other stream is sent to the temperature swing adsorption unit 8; the first low-temperature methanol washing unit 4 and the second low-temperature methanol washing unit 6 respectively include but are not limited to shift gas washing tower, shallow shift gas washing tower, medium-pressure flash tower, CO2 analysis tower, H2S analysis tower, tail gas washing tower, methanol water separation tower and other equipment; the aforementioned shallow shift gas purification gas entering the temperature swing adsorption unit 8 is adsorbed and purified by the molecular sieve adsorber, and after removing a small amount of CH3OH, CO2 and other impurities contained in the shallow shift gas purification gas, the shallow shift gas purification gas is sent to the cryogenic separation unit 9, the molecular sieve adsorber can be regenerated after a period of operation, the regeneration gas is the replacement tail gas of the second pressure swing adsorption unit 16, and after regeneration, the regeneration gas can be burned in the combustion torch 17; wherein the temperature swing adsorption unit 8 includes but is not limited to molecular sieve adsorber, program-controlled valve and other equipment.The deep cooling separation unit 9 includes but is not limited to a cold box, a main heat exchanger, a hydrogen-rich gas flash tank, a stripping tower, a demethanizer, a denitrification tower, a CO compressor and the like; the impurity-removed shallowly shifted gas is introduced into the cold box, and after cooling, flashing, stripping, low-temperature rectification, cold energy recovery and the like, CO product gas and hydrogen-rich gas, methane-rich tail gas, nitrogen-rich tail gas and flash tail gas are obtained; the CO content in the product gas outlet of the deep cooling separation unit 9 is more than 98.5%, which can be sent to the CO product gas storage tank 10 for use or sold; the methane-rich tail gas in the methane-rich tail gas outlet 20 of the deep cooling separation unit 9 is composed of about 51-73% CO and 26-42% CH4; the nitrogen-rich tail gas in the nitrogen-rich tail gas outlet 21 of the deep cooling separation unit 9 is composed of about 60-85% CO and 15-40% N2; the above-mentioned methane-rich tail gas and nitrogen-rich tail gas are sent into the second pressure swing adsorption unit 16 for recovering CO components; the hydrogen-rich gas in the hydrogen-rich gas outlet 18 of the deep cooling separation unit 9 is composed of about 8-15% CO and 80-90% H2, and has a pressure of about 5-6 MPa(G), which can be sent into the first pressure swing adsorption unit 11 for recovering H2; the flash tail gas in the flash tail gas outlet 19 of the deep cooling separation unit 9 is composed of about 18-35% CO and 60-80% H2, which can be pressurized by the first circulating compressor 13 and then sent into the membrane separation unit 14 for recovering H2; the hydrogen-rich gas and the shifted gas purification gas from the second low-temperature methanol washing unit 6 can be introduced into the molecular sieve adsorption tower in the first pressure swing adsorption unit 11, and after adsorption purification, hydrogen gas with a purity of 99.9% (mol) is obtained, which can be sent into the H2 product gas storage tank 12 for use or sold; the adsorbed impurity components after desorption are tail gas, which is composed of about 50-70% CO and 25-43% H2, and can be pressurized by the first circulating compressor 13 and then sent into the membrane separation unit 14 for recovering H2; the first pressure swing adsorption unit 11 includes but is not limited to a hydrogen-adsorbing tower, a desorption gas buffer tank, a forward tank, a program-controlled valve and the like. The desorption tail gas in the desorption tail gas outlet 24 and the flash tail gas in the flash tail gas outlet 19 are pressurized by the first circulating compressor 13 and then sent into the membrane separation unit 14, the gas passes through a precision filter to remove possible small particles and liquid drops, is preheated by a heater and then enters the membrane separator for CO separation and purification; after the membrane separation, two streams of gas are obtained, one is a permeate gas composed of about 8-25% CO and 70-95% H2, which is pressurized by the second circulating compressor 15 and then sent to the first pressure swing adsorption unit 11 for recovering H2; the other is a non-permeate gas composed of about 80-95% CO and 2-6% N2, which is sent to the second pressure swing adsorption unit 16 for recovering CO; the membrane separation unit 14 includes but is not limited to a membrane separator, a heater, a forward tank, a circulating gas compressor and the like.The methane-rich tail gas, nitrogen-rich tail gas and non-permeation gas are sent to a CO adsorption tower of the second pressure swing adsorption unit 16, and after adsorption purification, enter a product gas buffer tank, a compressor is arranged at the outlet of the product gas buffer tank, a part of CO product gas is compressed by the compressor and sent into a CO product gas storage tank 10, and the other part is returned to the CO adsorption tower and used for replacing impurity components remaining in the adsorption tower; the replacement tail gas after replacement is sent to the temperature swing pressure swing adsorption unit 8 and used as regeneration gas; the replacement tail gas mainly comprises N2 and CH4, and the equipment in the second pressure swing adsorption unit 16 comprises but is not limited to a CO adsorption tower, a heater, a product buffer tank, a compressor, a replacement tail gas compressor and the like. The utility model makes full use of the existing coal synthetic ammonia system, adopts deep cooling separation and coupling membrane separation technology, pressure swing adsorption technology and the like, separates and purifies CO and H2 in coal synthetic gas, and fully recycles tail gas produced in the production process of each device while taking the CO and H2 as product or downstream chemical product synthesis raw materials. Therefore, the utility model not only provides a gas separation scheme for producing high-purity CO and H2 on a coal synthetic ammonia system, but also can fully recycle effective components in tail gas of deep cooling separation and each pressure swing adsorption device, thereby enhancing the ability of the enterprise to flexibly adjust downstream products, effectively reducing the consumption of raw materials.

[0026] The basic principle, main features and advantages of the utility model are shown and described above. It should be understood by those skilled in the art that the utility model is not limited by the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principle of the utility model, and various changes and improvements can be made to the utility model without departing from the spirit and scope of the utility model, and these changes and improvements all fall within the scope of the utility model claimed.

Claims

1. An apparatus for co-producing CO and H2 in a synthetic ammonia system, the apparatus comprising a coal gasification unit (1), the syngas outlet of the coal gasification unit (1) being connected to a heat recovery unit (3), characterized in that: The shallow shift gas pipeline in the heat recovery unit (3) is connected to the first low-temperature methanol washing unit (4). The shallow shift purified gas outlet of the first low-temperature methanol washing unit (4) is connected to the methanol synthesis system (5) and the CO purification section, respectively. The shift gas pipeline in the heat recovery unit (3) is connected to the second low-temperature methanol washing unit (6). The shift purified gas outlet of the second low-temperature methanol washing unit (6) is connected to the ammonia synthesis system (7) and the H2 purification section, respectively.

2. The apparatus for co-producing CO and H2 in an ammonia synthesis system according to claim 1, characterized in that: The CO purification unit includes at least a temperature and pressure swing adsorption unit (8), the inlet of which is connected to the outlet of the shallow change purification gas, the gas phase outlet of which is connected to the inlet of the cryogenic separation unit (9), and the product gas outlet of the cryogenic separation unit (9) is connected to the CO product gas storage tank (10).

3. The apparatus for co-producing CO and H2 in an ammonia synthesis system according to claim 2, characterized in that: The H2 purification unit includes a first pressure swing adsorption unit (11). The inlet of the first pressure swing adsorption unit (11) is connected to the conversion purification gas outlet of the second low-temperature methanol washing unit (6) and the hydrogen-rich gas outlet (18) of the cryogenic separation unit (9), respectively. The product gas outlet of the first pressure swing adsorption unit (11) is connected to the H2 product gas storage tank (12).

4. The apparatus for co-producing CO and H2 in an ammonia synthesis system according to claim 3, characterized in that: The H2 purification unit also includes a first circulating compressor (13), the inlet of which is connected to the desorption tail gas outlet (24) of the first pressure swing adsorption unit (11) and the flash tail gas outlet (19) of the cryogenic separation unit (9), respectively; the outlet of the first circulating compressor (13) is connected to the membrane separation unit (14), and the permeate outlet (22) of the membrane separation unit (14) is connected to the inlet of the first pressure swing adsorption unit (11) through the second circulating compressor (15).

5. The apparatus for co-producing CO and H2 in an ammonia synthesis system according to claim 4, characterized in that: The CO purification unit also includes a second pressure swing adsorption unit (16), the inlet of which is connected to the methane-rich tail gas outlet (20) of the cryogenic separation unit (9), the nitrogen-rich tail gas outlet (21) of the cryogenic separation unit (9), and the non-permeable gas outlet (23) of the membrane separation unit (14); the product gas outlet of the second pressure swing adsorption unit (16) is connected to the CO product gas storage tank (10).

6. The apparatus for co-producing CO and H2 in an ammonia synthesis system according to claim 5, characterized in that: The displacement tail gas outlet (2) of the second pressure swing adsorption unit (16) is connected to the regeneration gas inlet of the temperature swing adsorption unit (8).

7. An apparatus for co-producing CO and H2 in an ammonia synthesis system according to claim 2 or 6, characterized in that: The regeneration gas outlet of the temperature and pressure swing adsorption unit (8) is connected to the combustion torch (17).

Images