CO2 hydrogenation methanol preparation system suitable for various catalysts

Abstract

The utility model discloses a CO2 hydrogenation methanol preparation system suitable for various catalysts, which relates to the technical field of methanol synthesis, and comprises a compression assembly, a synthesis tower, a high-pressure separation tank and a throttling device, the compression assembly comprises a first compressor for receiving fresh synthesis gas and a second compressor for receiving recycle gas; the synthesis tower is filled with a catalyst and is used for reacting and converting gas discharged by the first compressor and the second compressor into a methanol-containing material; the high-pressure separation tank is used for receiving the methanol-containing material discharged by the synthesis tower and carrying out gas-liquid separation on the methanol-containing material to form circulating gas capable of entering the second compressor and liquid capable of entering the flash tank to form crude methanol; the throttling device is arranged between the high-pressure separation tank and an inlet of the second compressor so as to adjust the flow of circulating gas entering the second compressor; further, the recycle ratio of recycle gas to fresh synthesis gas can be adjusted so as to be suitable for various catalysts, and the dependence on specific catalysts is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of methanol synthesis, especially to a CO2 hydrogenation methanol system suitable for various catalysts. BACKGROUND

[0002] Carbon neutralization refers to the total amount of carbon dioxide or greenhouse gas emissions generated directly or indirectly within a certain period of time, which is offset by planting trees, energy saving and emission reduction and other forms to offset the carbon dioxide or greenhouse gas emissions generated by itself, so as to realize positive and negative offset; carbon dioxide (CO2) hydrogenation into fuel methanol (CH3OH) is a very potential research direction, which can not only solve the problem of excessive CO2 emission, but also reduce the consumption of fossil resources.

[0003] However, due to the limitation of thermodynamics, the single-pass conversion rate of CO2 hydrogenation methanol reaction is low, and the unreacted gas is usually circulated to improve the conversion rate, and different catalysts have different catalytic effects on different gas components.

[0004] Therefore, how to provide a CO2 hydrogenation methanol system suitable for various catalysts is a technical problem to be solved by those skilled in the art at present. UTILITY MODEL CONTENT

[0005] The utility model aims at providing a CO2 hydrogenation methanol system suitable for various catalysts, which is suitable for various catalysts and reduces the dependence on specific catalysts.

[0006] To achieve the above-mentioned purpose, the utility model provides a CO2 hydrogenation methanol system suitable for various catalysts, which comprises:

[0007] The compression assembly comprises a first compressor for receiving fresh synthesis gas and a second compressor for receiving circulating gas;

[0008] The synthesis tower is internally filled with catalysts, and the synthesis tower is used for reaction and conversion of the gas discharged by the first compressor and the second compressor into methanol-containing material;

[0009] The high-pressure separation tank is used for receiving the methanol-containing material discharged from the synthesis tower and carrying out gas-liquid separation on the methanol-containing material to form circulating gas capable of entering the second compressor and liquid capable of entering the flash tank to form crude methanol;

[0010] The throttling device is arranged between the high-pressure separation tank and the inlet of the second compressor to adjust the flow of the circulating gas entering the second compressor.

[0011] Preferably, the throttling device is a throttle valve arranged between the high-pressure separation tank and the inlet of the second compressor, and the throttle valve is specifically an adjustable butterfly valve.

[0012] Preferably, the throttling device is an adjustable guide vane arranged at the inlet of the second compressor.

[0013] Preferably, the synthesis tower is further provided with inert porcelain balls for uniformly filling the catalyst in the synthesis tower.

[0014] Preferably, the system further comprises a gas-gas heat exchanger, the shell side inlet of the gas-gas heat exchanger is connected to the outlet of the first compressor and the outlet of the second compressor, the shell side outlet of the gas-gas heat exchanger is connected to the inlet of the synthesis tower, the tube side inlet of the gas-gas heat exchanger is connected to the outlet of the synthesis tower, and the tube side outlet of the gas-gas heat exchanger is connected to the inlet of the high-pressure separation tank.

[0015] Preferably, a cooling device is further arranged between the tube side outlet of the gas-gas heat exchanger and the high-pressure separation tank, and the cooling device is used to cool the methanol-containing material after heat exchange in the gas-gas heat exchanger.

[0016] Preferably, the cooling device is specifically a lithium bromide unit, a heat pump, or a waste heat power generation device.

[0017] Preferably, the system further comprises a steam drum, the liquid outlet at the bottom of the steam drum is connected to the lower annular pipe of the synthesis tower, the steam outlet at the upper part of the synthesis tower is connected to the steam inlet of the steam drum, and the steam drum is provided with a boiler water supply port for water supply and a medium-pressure steam port for steam discharge.

[0018] Preferably, the inlet of the flash tank is connected to the outlet of the high-pressure separation tank, so that the liquid separated by the high-pressure separation tank is subjected to gas-liquid separation to form crude methanol and purge gas, and the flash tank is provided with a first outlet for discharging the crude methanol and a second outlet for discharging the purge gas.

[0019] Preferably, the gas-gas heat exchanger is specifically a spiral pipe type gas-gas heat exchanger.

[0020] With respect to the above background technology, the CO2 hydrogenation methanol system suitable for multiple catalysts provided by the utility model comprises a compression assembly, a synthesis tower, a high-pressure separation tank and a throttling device, the compression assembly comprises a first compressor for receiving fresh synthesis gas and a second compressor for receiving circulating gas; the synthesis tower is filled with a catalyst, and the synthesis tower is used for reaction conversion of the gas discharged by the first compressor and the second compressor into methanol-containing material; the high-pressure separation tank is used for receiving the methanol-containing material discharged by the synthesis tower, and the methanol-containing material is subjected to gas-liquid separation to form circulating gas capable of entering the second compressor and liquid capable of entering a flash tank to form crude methanol; the throttling device is arranged between the high-pressure separation tank and the inlet of the second compressor to adjust the flow of the circulating gas entering the second compressor.

[0021] Specifically, the methanol-containing material discharged from the synthesis tower is subjected to gas-liquid two-phase separation through a high-pressure separation tank, the gas separated through the high-pressure separation tank is taken as circulating gas and enters the second compressor, is compressed, is mixed with fresh synthesis gas compressed by the first compressor, and then flows into the synthesis tower again, and further reacts under the catalysis of the catalyst, a throttling device is arranged between the high-pressure separation tank and the inlet of the second compressor to adjust the flow of the circulating gas entering the second compressor, and then the circulation ratio of the circulating gas and the fresh synthesis gas can be adjusted, so that the system is suitable for various catalysts, and the dependence on specific catalysts is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0023] Figure 1 The structure diagram of the CO2 hydrogenation to methanol system suitable for various catalysts provided by the embodiments of the present application.

[0024] Among them:

[0025] 1-steam drum, 2-synthesis tower, 3-gas-gas heat exchanger, 4-cooling device, 5-first compressor, 6-second compressor, 7-high-pressure separation tank, 8-flash tank, 9-throttle valve. DETAILED DESCRIPTION

[0026] The technical scheme 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 part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0027] In order to make those skilled in the art better understand the technical scheme of the present application, the present application will be further described in detail below in combination with the drawings and specific embodiments.

[0028] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left" and "right" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated position or element must have a specific orientation, be constructed and operated in a specific orientation, therefore it cannot be understood as a limitation of the present application.

[0029] The utility model discloses a kind of CO2 hydrogenation methanol systems suitable for multiple catalysts, suitable for multiple catalysts, reduce the dependence on specific catalyst.

[0030] Please refer to Figure 1 To achieve the above object, the utility model provides a kind of CO2 hydrogenation methanol systems suitable for multiple catalysts, including compression component, synthesis tower 2, high-pressure separation tank 7 and throttling device, compression component includes the first compressor 5 for receiving fresh synthesis gas and the second compressor 6 for receiving circulating gas;Synthesis tower 2 is filled with catalyst inside, and synthesis tower 2 is used for the gas reaction conversion of first compressor 5 and second compressor 6 discharge into methanol-containing material;High-pressure separation tank 7 is used to receive the methanol-containing material discharged through synthesis tower 2, and the methanol-containing material is carried out gas-liquid separation, to form the circulating gas that can enter second compressor 6 and the liquid that can enter flash tank 8 to form crude methanol;Throttling device is arranged between high-pressure separation tank 7 and the inlet of second compressor 6, to adjust the flow of circulating gas entering second compressor 6.

[0031] CO2 hydrogenation methanol system suitable for multiple catalysts also includes gas-gas heat exchanger 3, the shell side entrance of gas-gas heat exchanger 3 is connected with the outlet of first compressor 5 and the outlet of second compressor 6, the shell side outlet of gas-gas heat exchanger 3 is connected with the inlet of synthesis tower 2, the tube side entrance of gas-gas heat exchanger 3 is connected with the outlet of synthesis tower 2, and the tube side outlet of gas-gas heat exchanger 3 is connected with the inlet of high-pressure separation tank 7;Cooling equipment 4 is also provided between the tube side outlet of gas-gas heat exchanger 3 and high-pressure separation tank 7, and cooling equipment 4 is used to cool methanol-containing material after heat exchange through gas-gas heat exchanger 3, and cooling equipment 4 is specifically lithium bromide unit, or heat pump, or waste heat power generation equipment and the like waste heat recovery equipment to recover reaction heat.

[0032] Among them, gas-gas heat exchanger 3 is specifically around tube type gas-gas heat exchanger 3, which not only solves the possible leakage mutual string of tube shell side caused by material limitation of floating head heat exchanger, but also greatly improves heat transfer efficiency and recovers energy.

[0033] Through high-pressure separation tank 7, methanol-containing material discharged from synthesis tower 2 is carried out gas-liquid two-phase separation, and the gas separated through high-pressure separation tank 7 enters second compressor 6 as circulating gas after compression, and then flows into synthesis tower 2 again after mixing with fresh synthesis gas compressed through first compressor 5, further reacts under the catalysis of catalyst, throttling device is arranged between high-pressure separation tank 7 and the inlet of second compressor 6 to adjust the flow of circulating gas entering second compressor 6, to further adjust the circulation ratio of circulating gas and fresh synthesis gas, flexibly adjust second compressor 6 to realize large-range flexible adjustment of circulation amount, to be suitable for multiple catalysts, reduce the dependence on specific catalyst.

[0034] In one embodiment, fresh synthesis gas is compressed from 1.6 MPaG to 8.0-9.0 MPaG by the first compressor 5, mixed with the circulating gas from the outlet of the second compressor 6, and sent to the gas-to-gas heat exchanger 3 for preheating. The temperature after preheating is 210-230°C. The preheated mixed gas is then sent to the synthesis tower 2 for methanol synthesis in the tube side.

[0035] The methanol-containing material at the bottom of synthesis tower 2 enters gas-gas heat exchanger 3 to recover part of the reaction heat. After cooling, the reaction gas enters cooling equipment 4 for further cooling. After further cooling, the gas-liquid two-phase reaction gas is separated in high-pressure separator 7. Unreacted raw materials enter the second compressor 6 from the top of high-pressure separator 7 and are compressed from 7.5-8.5 MPaG to 8.0-9.0 MPaG for circulation. Crude methanol is discharged from the bottom of high-pressure separator 7 and enters flash tank 8 for flash evaporation to remove dissolved CO2.

[0036] The fresh synthesis gas contains 73 mol% to 77 mol% hydrogen and 23 mol% to 27 mol% carbon dioxide, and preferably the molar ratio of hydrogen to carbon dioxide in the fresh synthesis gas is 3:1. The catalyst in synthesis tower 2 is a Cu-Zn-Al catalyst, and the circulation ratio of circulating gas to fresh gas is about 3 to 4.

[0037] In another embodiment, fresh synthesis gas is compressed from 1.6 MPaG to 8.0-9.0 MPaG by the first compressor 5, mixed with the circulating gas from the outlet of the second compressor 6, and sent to the gas-gas heat exchanger 3 for preheating. The temperature after preheating is 210-240°C. The preheated mixed gas is then sent to the synthesis tower 2 for methanol synthesis in the tube side.

[0038] The methanol-containing material at the bottom of synthesis tower 2 enters gas-gas heat exchanger 3 to recover part of the reaction heat. After cooling, the reaction gas enters cooling equipment 4 for further cooling. After further cooling, the gas-liquid two-phase reaction gas is separated in high-pressure separator 7. Unreacted raw materials enter the circulating gas compressor from the top of high-pressure separator 7 and are compressed from 7.5-8.5 MPaG to 8.0-9.0 MPaG for circulation. Crude methanol is discharged from the bottom of high-pressure separator 7 and enters flash tank 8 for flash evaporation to remove dissolved CO2.

[0039] The fresh synthesis gas contains 73 mol% to 77 mol% hydrogen and 23 mol% to 27 mol% carbon dioxide gas. The catalyst in synthesis tower 2 is a ZnZrOx catalyst, and the recycle ratio of the circulating gas to the fresh gas is about 5 to 6.

[0040] In the embodiment, the throttling device is a throttle valve 9 arranged between the high-pressure separation tank 7 and the inlet of the second compressor 6, and the throttle valve 9 is specifically an adjustable butterfly valve. The circulation gas flow is adjusted by the variable speed of the second compressor 6 and the adjustable butterfly valve, and then the circulation ratio of the circulation gas and the fresh synthesis gas is adjusted. In addition, the throttling device can also be an adjustable guide vane arranged at the inlet of the second compressor 6. The circulation gas flow is also adjusted by the variable speed of the second compressor 6 and the adjustable guide vane at the inlet, and then the circulation ratio of the circulation gas and the fresh synthesis gas is adjusted. The synthesis tower 2 is also provided with inert porcelain balls. The inert porcelain balls are used to uniformly disperse and fill the catalyst in the synthesis tower 2. The synthesis tower 2 with a high catalyst loading capacity can be arranged to promote the effect of converting the mixed gas into the methanol-containing material. The catalyst with good activity but deviation can be used. The inert porcelain ball serves as a catalyst support. In this way, the enterprise project reconstruction is facilitated, and the domestic substitution of the CO2 hydrogenation methanol catalyst is supported.

[0041] It can be understood that the CO2 hydrogenation methanol system further includes a steam drum 1. A liquid outlet at the bottom of the steam drum 1 is communicated with a lower ring pipe of the synthesis tower 2. A steam outlet at the upper part of the synthesis tower 2 is communicated with a steam inlet of the steam drum 1. The steam drum 1 is provided with a boiler water supply port for water supply and a medium-pressure steam port for steam discharge. The boiler water supply flow entering the boiler water supply port is circulated to the synthesis tower 2, absorbs the reaction heat generated by the reaction of CO2 and hydrogen, and is circulated to the steam drum 1 along the upper steam outlet of the synthesis tower 2, and finally is discharged from the steam drum 1 in the form of medium-pressure steam.

[0042] The inlet of the flash tank 8 is connected to the outlet of the high-pressure separation tank 7, so as to separate the liquid separated by the high-pressure separation tank 7 into crude methanol and purge gas through gas-liquid separation. The flash tank 8 is provided with a first outlet for discharging the crude methanol and a second outlet for discharging the purge gas.

[0043] In summary, the application provides a CO2 hydrogenation methanol system suitable for various catalysts, which has the advantages of convenient circulation flow adjustment, high heat recovery rate, and catalyst domestic substitution, etc. The system includes a methanol synthesis unit and a methanol gas-liquid separation unit. The methanol synthesis unit includes a steam drum 1, a synthesis tower 2, a gas-gas heat exchanger 3, a first compressor 5 and a second compressor 6, which are used for methanol synthesis with different catalysts. The methanol gas-liquid separation unit includes the gas-gas heat exchanger 3 (i.e., the gas-gas heat exchanger 3 is shared by the methanol synthesis unit and the methanol gas-liquid separation unit for heat exchange of the mixed gas and the methanol-containing material), a cooling device 4, a high-pressure separation tank 7, a flash tank 8 and a throttling device, which are used for separation of unreacted gas, inert gas and methanol product, to obtain a crude methanol product, and to circulate the unreacted raw material gas to the system to improve the total conversion rate of the raw material.

[0044] The first compressor 5 inlet is communicated with the gas phase outlet of the high-pressure separation tank 7, and a throttling device is arranged in between; the second compressor 6 outlet is communicated with the inlet of the shell side of the spiral wound gas-gas heat exchanger 3 after being merged with the outlet of the first compressor 5; the outlet of the shell side of the spiral wound gas-gas heat exchanger 3 is communicated with the top inlet of the synthesis tower 2; the bottom outlet of the synthesis tower 2 is communicated with the inlet of the tube side of the spiral wound gas-gas heat exchanger 3; the liquid outlet at the bottom of the steam drum 1 is communicated with the lower ring of the synthesis tower 2; the upper steam outlet of the synthesis tower 2 is communicated with the steam inlet of the steam drum 1; the steam drum 1 is provided with a boiler feed water inlet and a medium-pressure steam outlet; the tube side inlet of the spiral wound gas-gas heat exchanger 3 is communicated with the bottom outlet of the synthesis tower 2; the tube side outlet of the spiral wound gas-gas heat exchanger 3 is communicated with the inlet of the cooling device 4; the outlet of the cooling device 4 is communicated with the inlet of the high-pressure separation tank 7; the gas phase outlet of the high-pressure separation tank 7 is communicated with the throttling device; the throttling device is communicated with the inlet of the second compressor 6; the liquid phase outlet of the high-pressure separation tank 7 is communicated with the inlet of the flash tank 8; the first outlet at the bottom of the flash tank 8 is communicated with a crude methanol outlet pipeline; the second outlet at the top of the flash tank 8 is communicated with a purge gas outlet pipeline.

[0045] The second compressor 6 is flexibly adjusted to realize flexible adjustment of the circulation amount in a large range, and the adjustment is realized by changing the rotating speed of the second compressor 6 and increasing the inlet throttling adjustment or by changing the rotating speed of the second compressor 6 and increasing the inlet adjustable guide vane adjustment; the synthesis tower 2 with a high catalyst loading amount is arranged, and the catalyst with a relatively excellent activity but with a deviation is suitable; the spiral wound gas-gas heat exchanger 3 is selected, which not only solves the possible mutual leakage of the tube side and the shell side caused by the material limitation of the floating head heat exchanger but also greatly improves the heat transfer efficiency and recovers energy; and the spiral wound gas-gas heat exchanger 3 can provide convenience for enterprise project reconstruction and support for the domestic substitution of the CO2 hydrogenation methanol catalyst.

[0046] It should be noted that the relational terms such as first and second, and the like, are used merely to distinguish one entity from another entity, and do not necessarily require or imply that the entities are in any way mutually exclusive or be arranged in any specific order.

[0047] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between various embodiments can be referred to each other.

[0048] The principle and implementation mode of the utility model are described by using specific examples in the specification, and the description of the above embodiments is only used to help understand the method and core idea of the utility model. It should be pointed out that the ordinary skilled in the art can make some improvements and modifications to the utility model without departing from the principle of the utility model, and these improvements and modifications also fall within the protection scope of the utility model.

Claims

1. A CO2 hydrogenation to methanol system suitable for a plurality of catalysts, characterized in that, The application relates to a methanol synthesis device, comprising: a compression assembly, which comprises a first compressor (5) for receiving fresh synthesis gas and a second compressor (6) for receiving circulating gas; a synthesis tower (2) filled with catalysts, and the synthesis tower (2) is used for reaction conversion of the gas discharged by the first compressor (5) and the second compressor (6) into methanol-containing material; a high-pressure separation tank (7) for receiving the methanol-containing material discharged by the synthesis tower (2) and carrying out gas-liquid separation on the methanol-containing material to form circulating gas capable of entering the second compressor (6) and liquid capable of entering a flash tank (8) to form crude methanol; a throttling device arranged between the high-pressure separation tank (7) and the inlet of the second compressor (6) to adjust the flow of the circulating gas entering the second compressor (6).

2. The CO2 hydrogenation to methanol system suitable for multiple catalysts according to claim 1, wherein, The throttling device is a throttle valve (9) arranged between the high-pressure separation tank (7) and the inlet of the second compressor (6), and the throttle valve (9) is specifically an adjustable butterfly valve.

3. The CO2 hydrogenation to methanol system suitable for multiple catalysts according to claim 1, wherein, The throttling device is an adjustable guide vane arranged at the inlet of the second compressor (6).

4. The CO2 hydrogenation to methanol system suitable for multiple catalysts according to claim 1, wherein, The synthesis tower (2) is further provided with inert porcelain balls, and the inert porcelain balls are used for uniformly dispersing and filling the catalysts in the synthesis tower (2).

5. The CO2 hydrogenation to methanol system suitable for multiple catalysts according to any one of claims 1-4, characterized in that, The device further comprises a gas-gas heat exchanger (3), the shell side inlet of the gas-gas heat exchanger (3) is communicated with the outlet of the first compressor (5) and the outlet of the second compressor (6), the shell side outlet of the gas-gas heat exchanger (3) is communicated with the inlet of the synthesis tower (2), the tube side inlet of the gas-gas heat exchanger (3) is communicated with the outlet of the synthesis tower (2), and the tube side outlet of the gas-gas heat exchanger (3) is communicated with the inlet of the high-pressure separation tank (7).

6. The CO2 hydrogenation to methanol system suitable for multiple catalysts according to claim 5, wherein, A cooling device (4) is further arranged between the tube side outlet of the gas-gas heat exchanger (3) and the high-pressure separation tank (7), and the cooling device (4) is used for cooling the methanol-containing material after heat exchange of the gas-gas heat exchanger (3).

7. The CO2 hydrogenation to methanol system suitable for multiple catalysts according to claim 6, wherein, The cooling device (4) is specifically a lithium bromide unit, a heat pump or a waste heat power generation device.

8. The CO2 hydrogenation to methanol system suitable for multiple catalysts according to claim 6, wherein, The device further comprises a steam drum (1), the bottom liquid outlet of the steam drum (1) is communicated with the lower ring pipe of the synthesis tower (2), the upper steam outlet of the synthesis tower (2) is communicated with the steam inlet of the steam drum (1), and the steam drum (1) is provided with a boiler water supply port for water supply and a medium-pressure steam port for steam discharge.

9. The CO2 hydrogenation to methanol system suitable for multiple catalysts according to claim 6, wherein, The inlet of the flash tank (8) is connected to the outlet of the high-pressure separation tank (7), so that the liquid separated by the high-pressure separation tank (7) is subjected to gas-liquid separation to form crude methanol and purge gas, and the flash tank (8) is provided with a first outlet for discharging the crude methanol and a second outlet for discharging the purge gas.

10. The CO2 hydrogenation to methanol system suitable for multiple catalysts of claim 6, wherein, The gas-gas heat exchanger (3) is specifically a coiled pipe type gas-gas heat exchanger.

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