Recovery system for hydrogen in ethylbenzene catalytic dehydrogenation tail gas

Abstract

The utility model provides a system for recovering hydrogen in ethylbenzene catalytic dehydrogenation tail gas, which comprises pressurizing equipment, a first gas-liquid separator, a second gas-liquid separator, a degreaser and a pressure swing adsorption (PSA) device which are sequentially communicated through pipelines, a dehydrogenation tail gas input pipeline and a pressurizing tail gas output pipeline are arranged on the pressurizing equipment, and the pressurizing tail gas output pipeline is communicated with the deoiler. A first gas-liquid separator input pipeline and a second gas-liquid separator input pipeline are connected with the pressurized tail gas output pipeline, a first electromagnetic valve is arranged on the first gas-liquid separator input pipeline, and compressed tail gas enters a first gas-liquid separator through the first gas-liquid separator input pipeline; a first gas-liquid separator outlet pipeline is arranged on the first gas-liquid separator, a second electromagnetic valve is arranged on the first gas-liquid separator outlet pipeline, a water drainage pipeline is arranged on the bottom surface of the first gas-liquid separator, and a first water drainage electromagnetic valve is arranged on the water drainage pipeline; the second gas-liquid separator and the first gas-liquid separator are the same in structure and connection relation.

Description

Technical Field

[0001] The utility model relates to the technical field of styrene production, in particular to a hydrogen recovery system for the tail gas of ethylbenzene catalytic dehydrogenation. Background Art

[0002] At present, there are two main ways to prepare styrene from ethylbenzene. One is the ethylbenzene catalytic dehydrogenation method, and the other is the ethylbenzene oxidative dehydrogenation method. In the ethylbenzene catalytic dehydrogenation method, the main reaction is: The tail gas of the ethylbenzene catalytic dehydrogenation method contains a large amount of by-product hydrogen. In the traditional process, the hydrogen-rich tail gas is introduced into a steam boiler as boiler fuel. With the development of fuel cells, the price of hydrogen is much higher than that of fuel gas. Therefore, recovering hydrogen from the tail gas of ethylbenzene catalytic dehydrogenation has good economic value. At present, the pressure swing adsorption method (PSA) is used to recover hydrogen from the tail gas of ethylbenzene catalytic dehydrogenation to obtain high-purity hydrogen. However, the pressure of the tail gas of the ethylbenzene catalytic dehydrogenation method is relatively low, only about 43 kPa, while in the pressure swing adsorption method, the pressure needs to reach about 2.0 MPa. Therefore, the catalytic dehydrogenation tail gas needs to be compressed before entering the pressure swing adsorption device. However, the tail gas of the ethylbenzene catalytic dehydrogenation method contains free water, which will condense after compression, affecting the quality of high-purity hydrogen and shortening the service life of the adsorbent for adsorption / desorption. Summary of the Invention

[0003] In view of this, the utility model aims to provide a hydrogen recovery system for the tail gas of ethylbenzene catalytic dehydrogenation, which can remove the condensed water generated by compression before the tail gas of the ethylbenzene catalytic dehydrogenation method enters the pressure swing adsorption (PSA) device.

[0004] The utility model provides a hydrogen recovery system for ethylbenzene catalytic dehydrogenation tail gas, which includes a pressurizing device, a first gas-liquid separator, a second gas-liquid separator, an oil remover and a pressure swing adsorption device (PSA), and they are connected in sequence through pipelines. A dehydrogenation tail gas input pipeline and a pressurized tail gas output pipeline are provided on the pressurizing device. A first gas-liquid separator input pipeline and a second gas-liquid separator input pipeline are connected to the pressurized tail gas output pipeline. A first solenoid valve is provided on the first gas-liquid separator input pipeline, and the compressed tail gas enters the first gas-liquid separator through the first gas-liquid separator input pipeline. A first gas-liquid separator outlet pipeline is provided on the first gas-liquid separator, and a second solenoid valve is provided on the first gas-liquid separator outlet pipeline. A drain pipeline is provided on the bottom surface of the first gas-liquid separator, and a first drain solenoid valve is provided on the drain pipeline; the second gas-liquid separator has the same structure as the first gas-liquid separator and the same connection relationship. Specifically, a third solenoid valve is provided on the second gas-liquid separator input pipeline, and the compressed tail gas enters the second gas-liquid separator through the second gas-liquid separator input pipeline. A second gas-liquid separator outlet pipeline is provided on the second gas-liquid separator, and a fourth solenoid valve is provided on the second gas-liquid separator outlet pipeline. A drain pipeline is provided on the bottom surface of the first gas-liquid separator, and a second drain solenoid valve is provided on the drain pipeline.

[0005] Further, the pressure swing adsorption device is provided with two outlet pipelines, one is an analysis gas pipeline and the other is a high-purity hydrogen pipeline.

[0006] Further, a liquid level gauge is provided inside the first gas-liquid separator, which can measure the condensate liquid level in the first gas-liquid separator, and a first pressure gauge is also provided, which can measure the condensate liquid level in the first gas-liquid separator.

[0007] Further, the condensate liquid level in the second gas-liquid separator can be measured, and a second pressure gauge is also provided, which can measure the condensate liquid level in the second gas-liquid separator.

[0008] Further, the first liquid level gauge is provided with upper and lower limits and is electrically connected to the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve and the first drain solenoid valve.

[0009] Further, the second liquid level gauge is provided with upper and lower limits and is electrically connected to the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve and the second drain solenoid valve.

[0010] Further, a first pressure compensation pipeline is also provided on the first gas-liquid separator, and a fifth solenoid valve is provided on the first pressure compensation pipeline; a second pressure compensation pipeline is also provided on the second gas-liquid separator, and a sixth solenoid valve is provided on the second pressure compensation pipeline.

[0011] Further, the fifth solenoid valve is electrically connected to the first pressure gauge, and the sixth solenoid valve is electrically connected to the second pressure gauge.

[0012] Further, a liquid capture device is provided in the first gas-liquid separator and / or the second gas-liquid separator. The liquid capture device is composed of a main body, a refrigerant inlet pipe, and a refrigerant outlet pipe. A number of holes are provided in the main body.

[0013] Beneficial effects:

[0014] A hydrogen recovery system for ethylbenzene catalytic dehydrogenation tail gas provided by the present invention includes a pressurizing device, a first gas-liquid separator, a second gas-liquid separator, an oil remover, and a pressure swing adsorption device (PSA), which are sequentially connected in series through pipelines. The pressurizing device is provided with a dehydrogenation tail gas input pipeline and a pressurized tail gas output pipeline. A first gas-liquid separator input pipeline and a second gas-liquid separator input pipeline are connected to the pressurized tail gas output pipeline. A first solenoid valve is provided on the first gas-liquid separator input pipeline. Compressed tail gas enters the first gas-liquid separator through the first gas-liquid separator input pipeline. A first gas-liquid separator outlet pipeline is provided on the first gas-liquid separator, and a second solenoid valve is provided on the first gas-liquid separator outlet pipeline. A drainage pipeline is provided at the bottom of the first gas-liquid separator, and a first drainage solenoid valve is provided on the drainage pipeline. The second gas-liquid separator has the same structure and connection relationship as the first gas-liquid separator. Specifically, a third solenoid valve is provided on the second gas-liquid separator input pipeline. Compressed tail gas enters the second gas-liquid separator through the second gas-liquid separator input pipeline. A second gas-liquid separator outlet pipeline is provided on the second gas-liquid separator, and a fourth solenoid valve is provided on the second gas-liquid separator outlet pipeline. A drainage pipeline is provided at the bottom of the first gas-liquid separator, and a second drainage solenoid valve is provided on the drainage pipeline. By providing two gas-liquid separators, the condensed water in the compressed tail gas can be removed. Through the switching of valves and pipelines, one can be in a working state and the other in a standby state, so that when the liquid level of any one reaches the upper limit and drainage work is carried out, it does not affect the continuous operation of the entire production line. Description of the drawings

[0015] Figure 1 It is a schematic diagram of a hydrogen recovery system for ethylbenzene catalytic dehydrogenation tail gas in the present invention;

[0016] Figure 2 It is a schematic diagram of the liquid capture device in the embodiment of the present invention;

[0017] Among them, the reference numerals in the figures are as follows: 1, pressurizing device; 11, dehydrogenation tail gas input pipeline; 12, pressurized tail gas output pipeline; 2, first gas-liquid separator; 21, first liquid level gauge; 22, second pressure gauge; 23, first gas-liquid separator input pipeline; 231, first solenoid valve; 24, first gas-liquid separator outlet pipeline; 241, second solenoid valve; 25, first pressure compensation pipeline; 251, fifth solenoid valve; 26, first drainage pipeline; 261, first drainage solenoid valve; 27, first liquid capture device; 3, second gas-liquid separator; 31, second liquid level gauge; 32, second pressure gauge; 33, second gas-liquid separator input pipeline; 331, third solenoid valve; 34, second gas-liquid separator outlet pipeline; 341, fourth solenoid valve; 35, second pressure compensation pipeline; 351, sixth solenoid valve; 36, second drainage pipeline; 361, second drainage solenoid valve; 37, second liquid capture device; 31, circulating cooling water inlet; 32, circulating cooling water outlet; 33, circulating water pump; 34, second solenoid valve; 35, second temperature sensor; 4, oil remover; 5, pressure swing adsorption device; 51, desorption gas pipeline; 52, high-purity hydrogen pipeline. Detailed implementation manners

[0018] To make the above objects, features and advantages of the present utility model more obvious and understandable, the following will describe in detail the specific implementation manners of the present utility model in combination with the embodiments of the specification. The methods are conventional methods unless otherwise specified, and the raw materials can be obtained from public commercial channels unless otherwise specified.

[0019] As used herein, the term "one embodiment" or "embodiment" refers to a specific feature, structure or characteristic that may be included in at least one implementation manner of the present utility model. The phrase "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that excludes other embodiments.

[0020] Such as Figure 1As shown in the figure, this embodiment provides a hydrogen recovery system for ethylbenzene catalytic dehydrogenation tail gas, which includes a pressurizing device 1, a first gas-liquid separator 2, a second gas-liquid separator 3, an oil remover 4 and a pressure swing adsorption device (PSA) 5, which are connected in sequence through pipelines. A dehydrogenation tail gas input pipeline 11 and a pressurized tail gas output pipeline 12 are provided on the pressurizing device 1. A first gas-liquid separator input pipeline 23 and a second gas-liquid separator input pipeline 33 are connected to the pressurized tail gas output pipeline 12. A first solenoid valve 231 is provided on the first gas-liquid separator input pipeline 23. The compressed tail gas enters the first gas-liquid separator 2 through the first gas-liquid separator input pipeline 23. A first gas-liquid separator outlet pipeline 24 is provided on the first gas-liquid separator 2. A liquid level gauge 21 is provided inside to measure the condensate liquid level in the first gas-liquid separator 2. A first pressure gauge 22 is also provided to measure the pressure in the first gas-liquid separator 2. A second solenoid valve 241 is provided on the first gas-liquid separator outlet pipeline 24. A drainage pipeline 26 is provided at the bottom of the first gas-liquid separator 2. A first drainage solenoid valve 261 is provided on the drainage pipeline 26. The second gas-liquid separator 3 has the same structure and connection relationship as the first gas-liquid separator 2. Specifically, a third solenoid valve 331 is provided on the second gas-liquid separator input pipeline 33. The compressed tail gas enters the second gas-liquid separator 3 through the second gas-liquid separator input pipeline 33. A second gas-liquid separator outlet pipeline 34 is provided on the second gas-liquid separator 3. A liquid level gauge 31 is provided inside to measure the condensate liquid level in the first gas-liquid separator 3. A second pressure gauge 32 is also provided to measure the pressure in the second gas-liquid separator 3. A fourth solenoid valve 341 is provided on the second gas-liquid separator outlet pipeline 34. A drainage pipeline 26 is provided at the bottom of the first gas-liquid separator 2. A second drainage solenoid valve 261 is provided on the drainage pipeline 26. The pressure swing adsorption device (PSA) 5 is provided with two outlet pipelines, one is an analysis gas pipeline 51 and the other is a high-purity hydrogen pipeline 52.

[0021] The first liquid level gauge 21 has upper and lower limits and is electrically connected to the first solenoid valve 231, the second solenoid valve 241, the third solenoid valve 331, the fourth solenoid valve 341 and the first drainage solenoid valve 261. Specifically, when the reading of the first liquid level gauge 21 reaches the upper limit, the third solenoid valve 331 and the fourth solenoid valve 341 are first controlled to open through an electrical signal, then the first solenoid valve 231 and the second solenoid valve 241 are controlled to close, and the second gas-liquid separator device 3 is switched to the working state. Finally, the first drainage solenoid valve 261 is controlled to open. When the reading of the first liquid level gauge 21 drops to the lower limit, the first drainage solenoid valve 261 is controlled to close through an electrical signal, and the first gas-liquid separator 2 is switched to the standby state.

[0022] Similarly, the second liquid level gauge 31 is provided with upper and lower limits and is electrically connected to the first solenoid valve 231, the second solenoid valve 241, the third solenoid valve 331, the fourth solenoid valve 341, and the second drain solenoid valve 361. Specifically, when the reading of the second liquid level gauge 31 reaches the upper limit, the first solenoid valve 231 and the second solenoid valve 241 are first controlled to open through an electrical signal, then the third solenoid valve 331 and the fourth solenoid valve 341 are controlled to close, and the first gas-liquid separator device 2 is switched to the working state. Finally, the second drain solenoid valve 361 is controlled to open. When the reading of the second liquid level gauge 31 drops to the lower limit, the second drain solenoid valve 361 is controlled to close through an electrical signal, and the second gas-liquid separator 2 is switched to the standby state.

[0023] In some embodiments, a first pressure compensation pipeline 25 is further provided on the first gas-liquid separator 2, and a fifth solenoid valve 251 is provided on the first pressure compensation pipeline 25. The fifth solenoid valve 251 is electrically connected to the first pressure gauge 22. Specifically, when the first drain solenoid valve is closed, the reading of the first pressure gauge 22 drops to the lowest and stops dropping, and an electrical signal is sent to control the fifth solenoid valve 251 to open, and pressure is supplemented into the first gas-liquid separator 2 through the first pressure compensation pipeline 25. When the pressure of the first pressure gauge 22 does not increase, an electrical signal is sent to control the fifth solenoid valve 251 to close. At this time, the pressure in the first gas-liquid separator 2 in the standby state is equal to the pressure in the second gas-liquid separator device 3 in the working state, so that there will be no pressure fluctuation during the drainage switching, which affects the subsequent working conditions.

[0024] Similarly, a second pressure compensation pipeline 35 is further provided on the second gas-liquid separator 3, and a sixth solenoid valve 351 is provided on the second pressure compensation pipeline 35. The sixth solenoid valve 351 is electrically connected to the second pressure gauge 32. Specifically, when the second drain solenoid valve is closed, the reading of the second pressure gauge 32 drops to the lowest and stops dropping, and an electrical signal is sent to control the sixth solenoid valve 351 to open, and pressure is supplemented into the second gas-liquid separator 3 through the second pressure compensation pipeline 35. When the pressure of the second pressure gauge 22 does not increase, an electrical signal is sent to control the sixth solenoid valve 351 to close. At this time, the pressure in the second gas-liquid separator 3 in the standby state is equal to the pressure in the first gas-liquid separator device 2 in the working state, so that there will be no pressure fluctuation during the drainage switching, which affects the subsequent working conditions.

[0025] In some embodiments, a first liquid capture device 27 is provided in the first gas-liquid separator 2. The main body 271 of the liquid capture device 27 is a hollow steel plate. A number of holes 272 for gas passage are provided on the main body 271. A refrigerant feed pipe 273 and a refrigerant discharge pipe 274 are connected to the main body 271. Circulating refrigerant can be introduced into the liquid capture device 27 through the refrigerant feed pipe 273 and the refrigerant discharge pipe 274. In this way, when the compressed tail gas flows through the holes 272 and contacts the low-temperature main body 271 of the liquid capture device 27, it is more likely to be condensed and collected.

[0026] Similarly, a second liquid capture device 37 can also be provided in the second gas-liquid separator 2. The structure is the same as that of the first liquid capture device 27 and will not be repeated here.

[0027] The working principle of the hydrogen recovery system for ethylbenzene catalytic dehydrogenation tail gas of the present utility model:

[0028] The dehydrogenation tail gas with a pressure of about 4 kPa is compressed by the pressurizing device 1, and the pressure rises to about 2 MPa. At this time, the free water in the dehydrogenation tail gas will turn into liquid. After passing through the first gas-liquid separator 2 to remove the moisture in the compressed tail gas, it enters the oil remover 4 to remove the high-carbon impurities in the tail gas, and finally enters the pressure swing adsorption device (PSA). The hydrogen meeting the quality standard (purity 99.9%) is collected through the high-purity hydrogen pipeline 52, and the desorbed gas is collected through the desorbed gas pipeline 51. When the reading of the liquid level gauge 21 in the first gas-liquid separator 2 reaches the upper limit, the second gas-liquid separator 3 is switched to the working state, and the first gas-liquid separator 2 drains water. After draining the water, it enters the standby state. When the reading of the liquid level gauge 31 in the second gas-liquid separator 3 reaches the upper limit, the first gas-liquid separator 2 is switched to the working state, and the second gas-liquid separator 3 drains water. After draining the water, it enters the standby state. The specific switching method has been described above and will not be elaborated here.

[0029] For the hydrogen recovery system for ethylbenzene catalytic dehydrogenation tail gas of the present utility model, two gas-liquid separators are provided, which can remove the condensed moisture in the compressed tail gas. Through the switching of valves and pipelines, one can be in the working state and the other in the standby state, so that when the liquid level of any one reaches the upper limit and drainage work is carried out, it does not affect the continuous operation of the entire production line.

[0030] The above embodiments are only used to illustrate the technical solutions of the present utility model and are not intended to limit them; although the present utility model has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present utility model.

Claims

1. A hydrogen recovery system for ethylbenzene catalytic dehydrogenation tail gas, comprising a pressurizing device, a first gas-liquid separator, a second gas-liquid separator, an oil remover and a pressure swing adsorption device (PSA), which are connected in sequence through pipelines, and is characterized in that, The pressurizing device is provided with a dehydrogenation tail gas input pipeline and a pressurized tail gas output pipeline. Connected to the pressurized tail gas output pipeline are a first gas-liquid separator input pipeline and a second gas-liquid separator input pipeline. A first solenoid valve is provided on the first gas-liquid separator input pipeline. The compressed tail gas enters the first gas-liquid separator through the first gas-liquid separator input pipeline. The first gas-liquid separator is provided with a first gas-liquid separator outlet pipeline, and a second solenoid valve is provided on the first gas-liquid separator outlet pipeline. The bottom surface of the first gas-liquid separator is provided with a drainage pipeline, and a first drainage solenoid valve is provided on the drainage pipeline; the second gas-liquid separator has the same structure as the first gas-liquid separator and the same connection relationship. Specifically, a third solenoid valve is provided on the second gas-liquid separator input pipeline. The compressed tail gas enters the second gas-liquid separator through the second gas-liquid separator input pipeline. The second gas-liquid separator is provided with a second gas-liquid separator outlet pipeline, and a fourth solenoid valve is provided on the second gas-liquid separator outlet pipeline. The bottom surface of the first gas-liquid separator is provided with a drainage pipeline, and a second drainage solenoid valve is provided on the drainage pipeline.

2. The hydrogen recovery system for the ethylbenzene catalytic dehydrogenation tail gas according to claim 1, characterized in that, The pressure swing adsorption device is provided with two outlet pipelines, one is an analysis gas pipeline and the other is a high-purity hydrogen pipeline.

3. The hydrogen recovery system for the tail gas of ethylbenzene catalytic dehydrogenation according to claim 1, wherein The first gas-liquid separator is internally provided with a first liquid level gauge, which can measure the condensate liquid level in the first gas-liquid separator, and also a first pressure gauge, which can measure the pressure in the first gas-liquid separator.

4. The hydrogen recovery system for the tail gas of ethylbenzene catalytic dehydrogenation according to claim 1, characterized in that, The second gas-liquid separator is internally provided with a second liquid level gauge, which can measure the condensate liquid level in the second gas-liquid separator, and also a second pressure gauge, which can measure the pressure in the second gas-liquid separator.

5. The hydrogen recovery system for the ethylbenzene catalytic dehydrogenation tail gas according to claim 3, characterized in that, The first liquid level gauge is provided with upper and lower limits and is electrically connected to the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve, and the first drainage solenoid valve.

6. The hydrogen recovery system for the ethylbenzene catalytic dehydrogenation tail gas according to claim 4, wherein The second liquid level gauge is provided with upper and lower limits and is electrically connected to the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve, and the second drainage solenoid valve.

7. The hydrogen recovery system for the ethylbenzene catalytic dehydrogenation tail gas according to claim 6, wherein The first gas-liquid separator is further provided with a first pressure compensation pipeline, and a fifth solenoid valve is provided on the first pressure compensation pipeline; the second gas-liquid separator is further provided with a second pressure compensation pipeline, and a sixth solenoid valve is provided on the second pressure compensation pipeline.

8. The hydrogen recovery system for the ethylbenzene catalytic dehydrogenation tail gas according to claim 7, characterized in that, The fifth solenoid valve is electrically connected to the first pressure gauge, and the sixth solenoid valve is electrically connected to the second pressure gauge.

9. The hydrogen recovery system for the tail gas of ethylbenzene catalytic dehydrogenation according to claim 4, wherein The first gas-liquid separator is internally provided with a first liquid capture device, which is composed of a main body, a refrigerant feed pipe, and a refrigerant discharge pipe. The main body is internally provided with a number of holes.

10. The hydrogen recovery system for the tail gas of ethylbenzene catalytic dehydrogenation according to claim 4, characterized in that, The second gas-liquid separator is internally provided with a second liquid capture device, and the second liquid capture device has the same composition structure as the first liquid capture device.

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