Methane hydrogen recovery device

Abstract

The utility model relates to the technical field of chemical production, and discloses a methane hydrogen recovery device which comprises a regeneration gas unit, a regeneration gas separation tank, a methane hydrogen compressor, a first overline pipeline and a second overline pipeline, the regeneration gas separation tank is connected with the regeneration gas unit through a second main pipeline, the methane hydrogen compressor is connected with the regeneration gas separation tank through a third main pipeline, and the methane hydrogen compressor is connected with the hydrogen production device through a fourth main pipeline; the first overline pipeline is connected with the first main pipeline and the second main pipeline, the second overline pipeline is connected with the first main pipeline and the third main pipeline, and each overline pipeline is provided with a regulating valve. Compared with the prior art, the methane hydrogen recovery device fully recovers the surplus methane hydrogen of the ethylene device and uses the surplus methane hydrogen as a raw material of the hydrogen production device, so that the problem that the surplus methane hydrogen of the ethylene device in the prior art can only release a torch is solved.

Description

Technical Field

[0001] This utility model relates to the field of chemical production technology, and in particular to a methane hydrogen recovery device. Background Technology

[0002] Ethylene plants use hydrocarbons as feedstock to primarily produce ethylene and propylene, with methane hydrogen, a byproduct, being a major source of fuel gas for chemical production. To avoid pipeline overpressure and ensure safe operation, most existing ethylene plants directly discharge excess methane hydrogen into the flare system to balance pipeline pressure. This reduces the comprehensive utilization rate and economic efficiency of ethylene plant byproducts, leading to increased energy consumption, resource waste, and environmental pollution. Furthermore, the methane hydrogen produced by ethylene plants typically consists of 95% methane and 5% hydrogen. However, daily production operations, including reactor regeneration, dryer regeneration, and flare gas recovery, cause frequent changes in the composition of methane hydrogen due to the addition of olefins. These changes affect the calorific value, and the increased olefin content limits external methane hydrogen distribution to systems with relatively crude combustion temperature control without modifications. This significantly restricts external methane hydrogen distribution and may even lead to the inability to find suitable users, ultimately necessitating flaring for disposal.

[0003] Therefore, how to optimize the methane hydrogen transmission device to fully recover and utilize the surplus methane hydrogen from the ethylene plant is a technical problem that urgently needs to be solved. Utility Model Content

[0004] To address the aforementioned technical problems, this utility model provides a methane hydrogen recovery device. This application adds a methane hydrogen bypass line, which directly sends the methane hydrogen from the cold box outlet to the inlet of the methane hydrogen compressor. This portion of the methane hydrogen does not pass through the regeneration gas separator, which can adapt to changes in fuel gas composition, avoid the impact of regeneration gas on externally supplied methane hydrogen, and maintain the normal and stable production of the hydrogen production unit.

[0005] To solve the above-mentioned technical problems, this utility model provides a methane hydrogen recovery device, which includes:

[0006] A regeneration gas unit is connected to a cold box via a first main pipeline, which is used to transmit methane hydrogen to the regeneration gas unit.

[0007] A regenerated gas separator tank is connected to the regenerated gas unit via a second main pipeline, the second main pipeline being used to transfer regenerated gas from the regenerated gas separator tank to the regenerated gas separator tank.

[0008] A methane-hydrogen compressor is connected to the regeneration gas separator via a third main pipeline. The third main pipeline is used to transfer dried methane-hydrogen to the methane-hydrogen compressor. The methane-hydrogen compressor is connected to a hydrogen production unit via a fourth main pipeline.

[0009] The first cross-line pipeline has an air inlet connected to the first main pipeline and an air outlet connected to the second main pipeline. The first cross-line pipeline is equipped with a regeneration gas differential pressure control valve.

[0010] The second cross-line pipeline has its inlet connected to the first main pipeline and its outlet connected to the third main pipeline. The second cross-line pipeline is equipped with a methane-hydrogen cross-line regulating valve.

[0011] In some embodiments of this application, a fifth main pipeline is also included, which is connected to the regeneration gas separator and is used to transfer dried methane hydrogen to the fuel gas system.

[0012] In some embodiments of this application, when the opening of the regeneration gas differential pressure control valve exceeds 30%, the methane hydrogen cross-line regulating valve increases its opening to reduce the intake volume of the main pipeline.

[0013] When the opening degree of the regeneration gas differential pressure control valve is less than 30%, the methane hydrogen cross-line regulating valve reduces its opening degree to increase the intake volume of the main pipeline.

[0014] This utility model provides a methane hydrogen recovery device, which has the following advantages compared with the prior art:

[0015] This application solves the problem that in the prior art, the surplus methane hydrogen in ethylene plants can only be released through a flare. By setting up a regeneration gas unit and a regeneration gas separator, the surplus methane hydrogen in the ethylene plant can be fully recovered and used as a raw material for hydrogen production, which saves energy, reduces emissions and improves economic efficiency.

[0016] This application, through the design of adding a second cross-line pipeline, ensures that the portion of the methane hydrogen entering the methane hydrogen compressor is not affected by the regeneration system, thereby preventing the methane hydrogen from continuing to react and generate system gases in the regeneration system, effectively limiting the olefin content in the methane hydrogen gas, and making it highly applicable to various ethylene plants.

[0017] This application adjusts the opening of the methane-hydrogen cross-line regulating valve according to the valve position change of the regeneration gas differential pressure control valve, ensuring normal regeneration gas differential pressure and valve position, and ensuring sufficient regeneration gas supply to the dryer. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the structure of the methane hydrogen recovery device according to an embodiment of this utility model.

[0019] In the diagram, 1 is the first main pipeline; 2 is the regenerated gas unit; 3 is the second main pipeline; 4 is the regenerated gas separator; 5 is the third main pipeline; 6 is the methane-hydrogen compressor; 7 is the fourth main pipeline; 8 is the first cross-line pipeline; 9 is the regenerated gas differential pressure control valve; 10 is the second cross-line pipeline; 11 is the methane-hydrogen cross-line regulating valve; and 12 is the fifth main pipeline. Detailed Implementation

[0020] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0021] In the description of this utility model, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] like Figure 1 As shown in the figure, the methane hydrogen recovery device provided in this embodiment includes a first main pipeline 1, a regeneration gas unit 2, a second main pipeline 3, a regeneration gas separator 4, a third main pipeline 5, a methane hydrogen compressor 6, a fourth main pipeline 7, a first cross-line pipeline 8, and a second cross-line pipeline 10. The regeneration gas unit 2 is connected to a cold box through the first main pipeline 1, which is used to transfer methane hydrogen to the regeneration gas unit 2. The regeneration gas separator 4 is connected to the regeneration gas unit 2 through the second main pipeline 3, which is used to transfer the regeneration gas from the regeneration gas separator 4 to the regeneration gas separator 4. The methane hydrogen compressor 6 is connected to the first main pipeline 1 through the third main pipeline 5, a second main pipeline 6, a third main pipeline 7, a fourth main pipeline 8, a first cross-line pipeline 8, and a second cross-line pipeline 10. The main pipeline 5 is connected to the regeneration gas separator 4. The third main pipeline 5 is used to transfer the dried methane hydrogen to the methane hydrogen compressor 6. The methane hydrogen compressor 6 is connected to the hydrogen production unit through the fourth main pipeline 7. Furthermore, the inlet of the first cross-line pipeline 8 is connected to the first main pipeline 1, and the outlet of the first cross-line pipeline 8 is connected to the second main pipeline 3. The first cross-line pipeline 8 is equipped with a regeneration gas differential pressure control valve 9. The inlet of the second cross-line pipeline 10 is connected to the first main pipeline 1, and the outlet of the second cross-line pipeline 10 is connected to the third main pipeline 5. The second cross-line pipeline 10 is equipped with a methane hydrogen cross-line regulating valve 11.

[0023] Based on the above structure, during use, the methane hydrogen flowing out of the cold box is divided into three streams according to the pipeline configuration. One stream enters the regeneration gas unit 2 as regeneration gas, and dries the gas produced by the ethylene unit. Another stream, as fuel gas, passes through the first cross-line pipeline 8 and is regulated by the regeneration gas differential pressure control valve 9 before heading to the regeneration gas separator 4. The third stream passes through the second cross-line pipeline 10 and is regulated by the methane hydrogen cross-line regulating valve 11 before heading to the methane hydrogen compressor 6 and finally being sent to the hydrogen production unit. Thus, the methane hydrogen from the cold box outlet passes through the first cross-line pipeline 8, bypasses the regeneration gas unit 2, and directly flows into the feed line (i.e., the second main pipeline 3) of the regeneration gas separator 4. With a constant outlet gas rate from the cold box, adjusting the opening of the regeneration gas differential pressure control valve 9 regulates the flow rate of methane hydrogen gas to the first cross-line pipeline 8, thereby regulating the flow rate of methane hydrogen gas entering the regeneration gas unit 2. Furthermore, the methane hydrogen from the cold box outlet also passes through the second cross-line pipeline 10, bypasses the regeneration gas unit 2 and the regeneration gas separator 4, and directly flows into the feed line (i.e., the third main pipeline 5) of the methane hydrogen compressor 6. With a constant outlet gas rate from the cold box outlet, adjusting the opening of the methane hydrogen cross-line regulating valve 11 regulates the flow rate of methane hydrogen gas to the second cross-line pipeline 10. Simultaneously, the methane hydrogen in the second cross-line pipeline 10 is unaffected by the regeneration system, maintaining stable composition, which helps reduce the olefin content entering the methane gas compressor and ensures the purity of the methane hydrogen gas delivered to the hydrogen production unit.

[0024] Specifically, the second cross-line pipeline 10 controls the flow rate of cross-line methane hydrogen by adjusting the opening of the methane hydrogen cross-line regulating valve 11. When the opening of the regeneration gas differential pressure control valve 9 is above 30%, the methane hydrogen cross-line regulating valve 11 is opened as wide as possible to be fully open. When the flow rate of regeneration gas supplied to the dryer of regeneration gas unit 2 increases, the regeneration gas differential pressure control valve 9 will be closed slightly. When the opening of the regeneration gas differential pressure control valve 9 is closed to less than 30%, the methane hydrogen cross-line regulating valve 11 is manually closed to reopen the regeneration gas differential pressure control valve 9 to above 30%. Therefore, under the conditions of ensuring sufficient regeneration gas supply to the dryer and maintaining the normal differential pressure of the regeneration gas system, the methane hydrogen from the cold box outlet is sent to the methane hydrogen compressor 6 across the regeneration gas system as much as possible.

[0025] Furthermore, the methane hydrogen recovery device of this application also includes a fifth main pipeline 12, which is connected to the regeneration gas separator 4. The fifth main pipeline 12 is used to transfer the dried methane hydrogen to the fuel gas system. Based on the above structure, the dried methane hydrogen produced by the regeneration gas separator 4 can also be transported to the fuel gas system for combustion through the fifth main pipeline 12 to provide energy for the operation of other devices.

[0026] In summary, the methane hydrogen recovery device of this utility model fully recovers the surplus methane hydrogen from the ethylene plant and uses it as a raw material for the hydrogen production unit by setting up a regeneration gas unit 2 and a regeneration gas separator 4, thereby saving energy, reducing emissions, and improving economic efficiency. The design of the newly added second cross-line pipeline 10 ensures that some of the methane hydrogen entering the methane hydrogen compressor 6 is not affected by the regeneration system, preventing the methane hydrogen from continuing to react and generate system gases in the regeneration system, effectively limiting the olefin content in the methane hydrogen gas, and making it highly applicable to various ethylene plants. The opening of the methane hydrogen cross-line regulating valve 11 is adjusted according to the valve position change of the regeneration gas differential pressure control valve 9 to ensure that the regeneration gas differential pressure and valve position are normal, ensuring that the amount of regeneration gas supplied to the dryer is sufficient.

[0027] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A methane hydrogen recovery device, characterized by, The application relates to a regenerative gas unit (2) connected with a cold box through a first main pipeline (1) for transmitting methane hydrogen to the regenerative gas unit (2), a regenerative gas separation tank (4) connected with the regenerative gas unit (2) through a second main pipeline (3) for transmitting regenerative gas of the regenerative gas separation tank (4) to the regenerative gas separation tank (4), a methane hydrogen compressor (6) connected with the regenerative gas separation tank (4) through a third main pipeline (5) for transmitting dried methane hydrogen to the methane hydrogen compressor (6), the methane hydrogen compressor (6) being connected with a hydrogen production device through a fourth main pipeline (7), a first cross-pipeline (8) with an air inlet connected with the first main pipeline (1) and an air outlet connected with the second main pipeline (3), the first cross-pipeline (8) being provided with a regenerative gas differential pressure control valve (9), a second cross-pipeline (10) with an air inlet connected with the first main pipeline (1) and an air outlet connected with the third main pipeline (5), the second cross-pipeline (10) being provided with a methane hydrogen cross-line regulating valve (11), a fifth main pipeline (12) connected with the regenerative gas separation tank (4) for transmitting dried methane hydrogen to a fuel gas system, and the regenerative gas differential pressure control valve (9) having an opening degree exceeding 30%, the methane hydrogen cross-line regulating valve (11) increasing the opening degree to reduce the air inlet amount of the main pipeline, and the regenerative gas differential pressure control valve (9) having an opening degree less than 30%, the methane hydrogen cross-line regulating valve (11) decreasing the opening degree to increase the air inlet amount of the main pipeline. The application relates to a regenerative gas unit (2) connected with a cold box through a first main pipeline (1) for transmitting methane hydrogen to the regenerative gas unit (2), a regenerative gas separation tank (4) connected with the regenerative gas unit (2) through a second main pipeline (3) for transmitting regenerative gas of the regenerative gas separation tank (4) to the regenerative gas separation tank (4), a methane hydrogen compressor (6) connected with the regenerative gas separation tank (4) through a third main pipeline (5) for transmitting dried methane hydrogen to the methane hydrogen compressor (6), the methane hydrogen compressor (6) being connected with a hydrogen production device through a fourth main pipeline (7), a first cross-pipeline (8) with an air inlet connected with the first main pipeline (1) and an air outlet connected with the second main pipeline (3), the first cross-pipeline (8) being provided with a regenerative gas differential pressure control valve (9), a second cross-pipeline (10) with an air inlet connected with the first main pipeline (1) and an air outlet connected with the third main pipeline (5), the second cross-pipeline (10) being provided with a methane hydrogen cross-line regulating valve (11), a fifth main pipeline (12) connected with the regenerative gas separation tank (4) for transmitting dried methane hydrogen to a fuel gas system, and the regenerative gas differential pressure control valve (9) having an opening degree exceeding 30%, the methane hydrogen cross-line regulating valve (11) increasing the opening degree to reduce the air inlet amount of the main pipeline, and the regenerative gas differential pressure control valve (9) having an opening degree less than 30%, the methane hydrogen cross-line regulating valve (11) decreasing the opening degree to increase the air inlet amount of the main pipeline. The application relates to a regenerative gas unit (2) connected with a cold box through a first main pipeline (1) for transmitting methane hydrogen to the regenerative gas unit (2), a regenerative gas separation tank (4) connected with the regenerative gas unit (2) through a second main pipeline (3) for transmitting regenerative gas of the regenerative gas separation tank (4) to the regenerative gas separation tank (4), a methane hydrogen compressor (6) connected with the regenerative gas separation tank (4) through a third main pipeline (5) for transmitting dried methane hydrogen to the methane hydrogen compressor (6), the methane hydrogen compressor (6) being connected with a hydrogen production device through a fourth main pipeline (7), a first cross-pipeline (8) with an air inlet connected with the first main pipeline (1) and an air outlet connected with the second main pipeline (3), the first cross-pipeline (8) being provided with a regenerative gas differential pressure control valve (9), a second cross-pipeline (10) with an air inlet connected with the first main pipeline (1) and an air outlet connected with the third main pipeline (5), the second cross-pipeline (10) being provided with a methane hydrogen cross-line regulating valve (11), a fifth main pipeline (12) connected with the regenerative gas separation tank (4) for transmitting dried methane hydrogen to a fuel gas system, and the regenerative gas differential pressure control valve (9) having an opening degree exceeding 30%, the methane hydrogen cross-line regulating valve (11) increasing the opening degree to reduce the air inlet amount of the main pipeline, and the regenerative gas differential pressure control valve (9) having an opening degree less than 30%, the methane hydrogen cross-line regulating valve (11) decreasing the opening degree to increase the air inlet amount of the main pipeline. ​ ​ ​ 2. The methane hydrogen recovery device according to claim 1, characterized by ​ 3. The methane hydrogen recovery device according to claim 1, characterized by ​ ​

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