Hydrogen purification system for power generator based on combined process of pressure swing adsorption and membrane separation

Abstract

The utility model discloses a generator hydrogen purification system based on pressure swing adsorption and membrane separation combined process, include: compressor, with generator high pressure side connection, pressure swing adsorption mechanism, its inlet is connected with compressor through the pipeline, and the bottom of pressure swing adsorption mechanism is connected to the blowdown pipeline, membrane separation mechanism, its inlet is connected with pressure swing adsorption mechanism, and the export is connected to generator low pressure side. The present application is through setting pressure swing adsorption mechanism and membrane separation mechanism, to pressure swing adsorption as preprocessing technique, utilize pressure swing adsorption mechanism one step to remove water, oil and part impurity gas in hydrogen, then use membrane separation technology to carry out the depth purification, can realize the purification effect maximization, and this purification system faces the technical demand that the working condition is mild, hydrogen recovery rate is high, and the area of land is small for generator hydrogen purification, can realize on -line purification, solves the problem that the generator hydrogen purity drops too fast, guarantees the safe and stable operation of unit.

Description

Technical Field

[0001] This utility model relates to the field of gas purification and enhancement, specifically to a generator hydrogen purification system based on a combined process of pressure swing adsorption and membrane separation. Background Technology

[0002] Hydrogen has low viscosity, high thermal conductivity, and significantly better insulation and arc-quenching effects than air. It offers excellent cooling, insulation, and reduced generator ventilation losses, thus rapidly replacing air as the superior cooling medium for generators and becoming widely applicable to large generator sets ranging from 300MW to 1000MW. However, generator efficiency is closely related to hydrogen purity. According to the "DL / T 1164-2012 Operating Guidelines for Steam Turbine Generators," the hydrogen purity inside water-hydrogen-cooled and fully hydrogen-cooled generators must be maintained above 96%, and ideally above 98% for even better operating efficiency. However, during unit operation, hydrogen purity can decrease due to defects in the sealing oil system, valve leaks, and other factors. Therefore, developing a process suitable for hydrogen purification in generators is a technical problem that needs to be solved.

[0003] In the chemical industry, hydrogen, as a major byproduct, has well-established and widely applied separation and purification processes. For example, pressure swing adsorption (PSA) and cryogenic distillation are used to separate hydrogen from mixed gases, and these methods can all increase hydrogen purity to over 98%, meeting the operational requirements of generator units. However, unlike the chemical industry, power plants typically implement hydrogen purification measures when the hydrogen purity reaches around 95% to meet production needs, and the purification scale is usually relatively small. Furthermore, most units have technical requirements for daily hydrogen emissions, necessitating strict control of the hydrogen content in the exhaust gas. Therefore, the technical requirements for generator hydrogen purification are fundamentally different from those in the chemical industry, and chemical purification technologies or equipment cannot be simply applied to generator hydrogen purification. Research indicates that impurities in generator hydrogen systems mainly include water, oil, gas, and other impurity gases. Considering the actual operating environment of power plants, it is necessary to develop a purification device with mild operating conditions, high hydrogen recovery rate, and small footprint. Utility Model Content

[0004] The technical problem to be solved by this utility model is: how to purify hydrogen in the generator hydrogen system online and solve the problem of the rapid decline in the purity of generator hydrogen.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0006] A generator hydrogen purification system based on a combined pressure swing adsorption and membrane separation process includes:

[0007] The compressor is connected to the high-voltage side of the generator;

[0008] The pressure swing adsorption mechanism has its inlet connected to the compressor via a pipeline, and its bottom connected to the sewage discharge pipeline.

[0009] The membrane separation unit has its inlet connected to the pressure swing adsorption unit and its outlet connected to the low-pressure side of the generator.

[0010] This application incorporates a pressure swing adsorption (PSA) mechanism and a membrane separation mechanism. PSA is used as a pretreatment technology to remove water, oil, and some impurities from hydrogen in a single step. Membrane separation technology is then used for further purification, maximizing the purification effect. This purification system addresses the technical requirements of generator hydrogen purification, demanding mild operating conditions, high hydrogen recovery rates, and a small footprint. It enables online purification, solves the problem of rapid hydrogen purity degradation in generators, and ensures the safe and stable operation of the unit.

[0011] As a further embodiment of this utility model: the pressure swing adsorption mechanism includes adsorption tower A and adsorption tower B, and the compressor is connected to adsorption tower A and adsorption tower B respectively through a three-way pipeline;

[0012] The outlets of adsorption tower A and adsorption tower B are both connected to the membrane separation unit via pipelines, and a branch pipe is also branched off from the outlets of adsorption tower A and adsorption tower B to connect the two to each other. A balancing valve is installed on this branch pipe.

[0013] As a further embodiment of this utility model: the pipeline connecting the compressor to adsorption tower A and adsorption tower B is equipped with an inlet flow meter and an inlet valve; the pipeline connecting the membrane separation mechanism to adsorption tower A and adsorption tower B is equipped with an inlet pressure gauge A and an outlet valve.

[0014] As a further embodiment of this utility model: the membrane separation mechanism includes a membrane separator A, and a hydrogen outlet valve and a product gas flow valve are provided on the pipeline connecting the membrane separator A and the generator. The product gas separated by the membrane separator A is controlled by the hydrogen outlet valve to return to the engine.

[0015] As a further embodiment of this utility model: a membrane separator B for tail gas recovery is connected to one side of the membrane separator A, and a membrane pressure gauge B is provided on the connecting pipeline between the two. The secondary permeate gas generated by the membrane separator B is returned to the purification pipeline before the compressor through the return pipeline or enters the pressure swing adsorption mechanism for regeneration.

[0016] As a further embodiment of this utility model, a secondary permeate flow meter is provided on the return pipe.

[0017] As a further embodiment of this utility model: the bottom outlet of the membrane separator B is connected to a sewage pipe, and a waste gas flow meter is installed on the sewage pipe.

[0018] As a further embodiment of this utility model, it also includes a control cabinet, inside which is a hydrogen purity detector, which is connected to several sampling pipes.

[0019] Several sampling pipes include sampling pipe 1, which is connected to the hydrogen inlet pipe of the compressor; sampling pipe 2, which is connected to the outlet pipe of the pressure swing adsorption unit; and sampling pipe 3, which is connected to the outlet pipe of the membrane separation unit.

[0020] As a further embodiment of this utility model, sampling valves are provided on sampling pipe one, sampling pipe two and sampling pipe three.

[0021] As a further embodiment of this utility model, the control cabinet is also equipped with a controller, a start / stop switch, and a gas leak alarm.

[0022] Compared with the prior art, the beneficial effects of this utility model are:

[0023] First, this application sets up a pressure swing adsorption (PSA) mechanism and a membrane separation mechanism. Using PSA as a pretreatment technology, the PSA mechanism removes water, oil, and some impurity gases from hydrogen in one step. Then, membrane separation technology is used for deep purification, which can maximize the purification effect. This purification system is designed to meet the technical requirements of mild working conditions, high hydrogen recovery rate, and small footprint required for hydrogen purification in generators. It can realize online purification, solve the problem of rapid decline in hydrogen purity in generators, and ensure the safe and stable operation of the unit.

[0024] Secondly, this purification system incorporates a reflux pipeline for secondary separation and recovery of the permeate gas purified by membrane separation. The recovered secondary permeate gas can be used in the pressure swing adsorption pretreatment section or returned to the purification system inlet for further purification, effectively improving the hydrogen recovery rate. Furthermore, both membrane separation and pressure swing adsorption technologies can be performed at room temperature, enhancing the safety of this purification system. Attached Figure Description

[0025] Figure 1 This is a block diagram of a generator hydrogen purification system using a combined pressure swing adsorption and membrane separation process according to an embodiment of this utility model.

[0026] Figure 2 This is a system block diagram showing the sampling pipeline hidden in an embodiment of the present invention;

[0027] Explanation of reference numerals in the attached figures:

[0028] 11. Generator; 12. Compressor; 13. Adsorption tower A; 14. Adsorption tower B; 15. Control cabinet; 16. Membrane separator A; 17. Membrane separator B;

[0029] 21. Hydrogen inlet valve; 22. Inlet valve A; 23. Inlet valve B; 24. Outlet valve A; 25. Outlet valve B; 26. Hydrogen outlet valve; 27. Reflux valve; 28. Balance valve;

[0030] 31. Drain valve A; 32. Drain valve B; 33. Drain valve C;

[0031] 41. Hydrogen inlet sampling valve; 42. Pressure swing adsorption outlet sampling valve; 43. Secondary permeate reflux port sampling valve; 44. Hydrogen outlet sampling valve;

[0032] 51. Inlet air flow meter; 52. Membrane inlet pressure gauge A; 53. Exhaust gas flow meter; 54. Secondary permeate gas flow meter; 55. Product gas flow valve; 56. Membrane inlet pressure gauge B. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below in conjunction with the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0034] Reference Figure 1 and Figure 2 A generator hydrogen purification system based on a combined pressure swing adsorption and membrane separation process includes a compressor 12, an adsorption tower A13, an adsorption tower B14, a membrane separator A16, a membrane separator B17, and a control cabinet 15.

[0035] Reference Figure 1 and Figure 2 The compressor 12 is connected to the high-pressure side of the generator 11 via a pipeline. A hydrogen inlet valve 21 is provided on the pipeline between the compressor 12 and the generator 11. The outlet end of the compressor 12 is connected to the adsorption tower A13 via a pipeline. An inlet flow meter 51 is provided on the pipeline between the adsorption tower A13 and the compressor 12. The flow rate of gas entering the compressor 12 is controlled by the hydrogen inlet valve 21, and the inlet flow meter 51 detects the inlet flow rate entering the adsorption tower A13.

[0036] Reference Figure 1 and Figure 2 Adsorption towers A13 and B14 are connected in parallel after compressor 12. That is, the outlet of compressor 12 is connected to the inlet of adsorption tower A13 and adsorption tower B14 respectively through a pipeline. The inlet of adsorption tower A13 and adsorption tower B14 is controlled by inlet valve A22 and inlet valve B23 respectively.

[0037] The bottoms of adsorption towers A13 and B14 are connected to the sewage discharge pipe via pipes. Sewage discharge valves A31 and B32 are respectively installed at the bottom sewage discharge ports of adsorption towers A13 and B14 to control the sewage discharge of the two towers.

[0038] The top outlets of adsorption tower A13 and adsorption tower B14 are connected to the inlet of membrane separator A16 via pipelines. Outlet valves A24 and B25 are respectively installed on the top outlet pipelines of adsorption tower A13 and adsorption tower B14 to control the exhaust of the two towers.

[0039] A branch line connects the outlet pipes of adsorption tower A13 and adsorption tower B14. This branch line connects the outlets of adsorption tower A13 and adsorption tower B14. A balancing valve 28 is installed on this branch line to control the pressure equalization between the two towers.

[0040] Reference Figure 1 Membrane separators A16 and B17 are connected sequentially after adsorption towers A13 and B14 to perform deep separation and purification of the raw gas after adsorption and purification.

[0041] A membrane inlet pressure gauge A52 is installed on the pipeline connecting the outlet of adsorption tower A13 and adsorption tower B14 to membrane separator A16. The membrane inlet pressure is detected by the membrane inlet pressure gauge A52, and the outlet valve A24 or outlet valve B25 controls the flow rate of the gas entering the membrane.

[0042] The outlet side of the membrane separator A16 is connected to the low-pressure side of the generator via a pipeline. The pipeline is equipped with a hydrogen outlet valve 26 and a product gas flow valve 55. The product gas separated by the membrane separator A16 is controlled by the hydrogen outlet valve 26 at the outlet of the membrane separator A16 to return to the low-pressure side of the engine. The product gas flow valve 55 is used to detect the product gas flow rate at this location.

[0043] Membrane separator B17 is used to recover the permeate gas from membrane separator A16. Membrane separator B17 and membrane separator A16 are connected by a pipeline, and an inlet pressure gauge B56 is installed on the connecting pipeline between the two. The bottom drain port of membrane separator B17 is connected to a drain pipe, and a drain valve C33 is installed at the drain port. An exhaust gas flow meter 53 is installed on the drain pipe. The inlet pressure is detected by the inlet pressure gauge B56, and the generated impurities and exhaust gas are discharged through the drain valve C33. The exhaust gas flow rate is detected by the exhaust gas flow meter 53.

[0044] Furthermore, the secondary permeate gas generated by the membrane separator B17 is returned to the purification system inlet via a reflux pipeline (i.e., the reflux pipeline is connected to the pipeline between the compressor 12 and the generator) or used for regeneration in the pressure swing adsorption process (i.e., the reflux pipeline is connected to the branch between the adsorption tower A13 and the adsorption tower B14, and a reflux valve 27 is provided at the connection between the two, and the reflux valve 27 controls the reflux of the secondary permeate gas). A secondary permeate gas flow meter 57 is provided on the reflux pipeline.

[0045] Reference Figure 1 The control cabinet 15 is equipped with a hydrogen purity detector, which is connected to four sampling pipelines: sampling pipeline 1, which is connected to the hydrogen inlet pipeline of the compressor; sampling pipeline 2, which is connected to the outlet pipeline of adsorption tower A13; sampling pipeline 3, which is connected to the outlet pipeline of membrane separator A16; and sampling pipeline 4, which is connected to the reflux pipeline of membrane separator B17.

[0046] The sampling pipeline is equipped with a hydrogen inlet sampling valve 41 on the first sampling pipeline, a pressure swing adsorption outlet sampling valve 42 on the second sampling pipeline, a hydrogen outlet sampling valve 44 on the third sampling pipeline, and a secondary permeate reflux port sampling valve 43 on the fourth sampling pipeline. The sampling pipeline can automatically detect the hydrogen purity, or it can be manually detected through the hydrogen inlet sampling valve 41, the hydrogen outlet sampling valve 44, the pressure swing adsorption outlet sampling valve 42, and the secondary permeate reflux port sampling valve 43.

[0047] The specific hydrogen purification process in this embodiment is as follows:

[0048] Step 1: The compressor drives the raw gas from the high-pressure side of the generator into the purification system. The inlet flow meter 51 and the hydrogen inlet valve 21 jointly control the inlet flow. After the raw gas enters the pressure swing adsorption step, the inlet valve A22 is opened, and the adsorption tower A13 completes the pollutant adsorption process. The inlet valve B23 is normally closed.

[0049] This step can remove water, oil and a small amount of gaseous impurities from the raw gas in one step. The gas purified by adsorption is discharged through outlet valve A24.

[0050] Step 2: After adsorption and purification, the raw gas enters the membrane separator A16 for membrane separation. The inlet pressure is detected by the inlet pressure gauge A52. After membrane separation and purification, the product gas is controlled by the hydrogen outlet valve 26 to return to the high-pressure side of the generator.

[0051] Tail gas recovery procedure: The primary permeate gas generated by membrane separator A16 enters membrane separator B17 for tail gas recovery, and the pressure is detected by inlet pressure gauge B56. The secondary permeate gas generated by membrane separator B17 returns to the purification system inlet through the reflux pipeline or is used for regeneration in the pressure swing adsorption step.

[0052] Adsorption-regeneration cycle process: When the adsorption capacity of adsorption tower A13 is saturated, open the balance valve 28 to activate the pressure equalization and discharge the "dead gas" at the top of adsorption tower A13 into adsorption tower B14. After the dead gas is discharged, open the drain valve A31 to enter the depressurization desorption and regeneration step; at this time, the inlet valve B23 should be opened to switch to adsorption tower B operation, forming the adsorption-regeneration cycle process.

[0053] Testing process: The control cabinet 15 is connected to the sampling pipeline and can automatically detect the hydrogen purity at the hydrogen inlet, hydrogen outlet, pressure swing adsorption outlet and secondary permeate return port; at the same time, the hydrogen purity can also be manually detected at the hydrogen inlet sampling valve 41, hydrogen outlet sampling valve 44, pressure swing adsorption outlet sampling valve 42 and secondary permeate return port sampling valve 43.

[0054] Control process: The control cabinet should have functions such as automatic detection of hydrogen purity, remote start and stop, leakage alarm, and valve control. The hydrogen purity can be preset, and the purification process will be started when the hydrogen purity drops to the set value.

[0055] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A generator hydrogen purification system based on a combined pressure swing adsorption and membrane separation process, characterized in that, include: The compressor (12) is connected to the high-voltage side of the generator; The pressure swing adsorption mechanism has its inlet connected to the compressor (12) via a pipeline, and its bottom is connected to the sewage pipe. The membrane separation unit has its inlet connected to the pressure swing adsorption unit and its outlet connected to the low-pressure side of the generator. The membrane separation mechanism includes a membrane separator A (16), and a membrane separator B (17) for tail gas recovery is connected to one side of the membrane separator A (16). A membrane pressure gauge B (56) is provided on the connecting pipeline between the two. The secondary permeate generated by the membrane separator B (17) is returned to the purification pipeline before the compressor (12) through the return pipeline or enters the pressure swing adsorption mechanism for regeneration.

2. The generator hydrogen purification system based on a combined pressure swing adsorption and membrane separation process according to claim 1, characterized in that: The pressure swing adsorption mechanism includes an adsorption tower A (13) and an adsorption tower B (14), and the compressor (12) is connected to the adsorption tower A (13) and the adsorption tower B (14) respectively through a three-way pipeline; The outlets of adsorption tower A (13) and adsorption tower B (14) are connected to the membrane separation mechanism through pipelines, and a branch pipe is also branched off from the outlets of adsorption tower A (13) and adsorption tower B (14) to connect the two to each other. A balance valve (28) is provided on the branch pipe.

3. The generator hydrogen purification system based on a combined pressure swing adsorption and membrane separation process according to claim 2, characterized in that: The compressor (12) is connected to the adsorption tower A (13) and adsorption tower B (14) by a flow meter (51) and an inlet valve; the membrane separation mechanism is connected to the adsorption tower A (13) and adsorption tower B (14) by a membrane pressure gauge A (52) and an outlet valve.

4. The generator hydrogen purification system based on a combined pressure swing adsorption and membrane separation process according to claim 1, characterized in that: The membrane separator A (16) is connected to the generator via a hydrogen outlet valve (26) and a product gas flow valve (55). The product gas separated by the membrane separator A (16) is controlled by the hydrogen outlet valve (26) to return to the engine.

5. The generator hydrogen purification system based on a combined pressure swing adsorption and membrane separation process according to claim 1, characterized in that: The return pipe is equipped with a secondary permeate flow meter (54).

6. The generator hydrogen purification system based on a combined pressure swing adsorption and membrane separation process according to claim 1, characterized in that: The bottom outlet of the membrane separator B (17) is connected to the sewage pipe, and the sewage pipe is equipped with an exhaust gas flow meter (53).

7. The generator hydrogen purification system based on a combined pressure swing adsorption and membrane separation process according to claim 1, characterized in that: It also includes a control cabinet (15), inside which is a hydrogen purity detector, which is connected to several sampling pipes.

8. The generator hydrogen purification system based on a combined pressure swing adsorption and membrane separation process according to claim 7, characterized in that: Several sampling pipes include sampling pipe 1, which is connected to the hydrogen inlet pipe of the compressor; sampling pipe 2, which is connected to the outlet pipe of the pressure swing adsorption unit; and sampling pipe 3, which is connected to the outlet pipe of the membrane separation unit.

9. The generator hydrogen purification system based on a combined pressure swing adsorption and membrane separation process according to claim 7, characterized in that: Sampling valves are installed on sampling pipe one, sampling pipe two and sampling pipe three.

10. The generator hydrogen purification system based on the combined process of pressure swing adsorption and membrane separation according to claim 7, characterized in that: The control cabinet (15) is also equipped with a controller, start / stop switch and gas leak alarm.

Images