Hydrogen fuel cell waste heat recovery system

Abstract

The utility model discloses a hydrogen fuel cell waste heat recovery system which comprises a hydrogen fuel cell and a hydrogen purification device, a hydrogen inlet of the hydrogen fuel cell is connected with the hydrogen purification device through a pipeline, byproduct hydrogen is introduced into the hydrogen purification device through a pipeline, and air is introduced into an air inlet of the hydrogen fuel cell through a pipeline. A waste gas outlet of the hydrogen fuel cell discharges waste gas through a pipeline, a water outlet of the hydrogen fuel cell is connected to a hot water inlet of the heat exchanger through a pipeline, and a hot water outlet of the heat exchanger is sequentially connected with a circulating pump and a water inlet of the air cooler through pipelines. And a water outlet of the air cooler is connected to a water inlet of the hydrogen fuel cell through a pipeline. According to the utility model, the waste heat generated in the running process of the hydrogen fuel cell is utilized in a thermodynamic system of a thermal power plant, so that the energy is utilized in a gradient manner, and the energy utilization efficiency is effectively improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of energy recovery, and particularly relates to a waste heat recovery system for a hydrogen fuel cell. Background Art

[0002] Hydrogen energy is an efficient and environmentally friendly energy source. A hydrogen fuel cell can convert hydrogen chemical energy into electrical energy, and the current mainstream hydrogen fuel cell conversion efficiency is about 50% - 60%. During the operation of a hydrogen fuel cell, a large amount of waste heat is generated. If this part of waste heat cannot be utilized, it will cause energy waste.

[0003] Meanwhile, in the field of chemical production, a large amount of by-product hydrogen is generated, so this part of by-product hydrogen can be effectively utilized. Similarly, during the chemical production process, a heat supply unit is required to supply heat, and there is a large amount of thermal energy in the heat supply unit that matches the waste heat of the hydrogen fuel cell. Therefore, there is an urgent need for an energy system that can match the hydrogen fuel cell with the heat supply unit, consume the by-product hydrogen nearby, and form an effective complementarity.

[0004] Chinese Patent with Publication No. CN211829036U discloses a fuel cell cooling system, a hydrogen fuel cell and a hydrogen fuel cell engine. The fuel cell cooling system includes an intake air cooling system for cooling the cathode intake air of the battery stack. The intake air cooling system includes an intake air heat exchanger, and a cathode gas flow path and a cooling medium flow path are formed inside the intake air heat exchanger; the outlet of the cathode gas flow path of the intake air heat exchanger is communicated with the cathode intake port of the battery stack, and the inlet of the cooling medium flow path of the intake air heat exchanger is communicated with the cathode exhaust port of the battery stack to introduce the exhaust gas discharged from the cathode exhaust port into the intake air heat exchanger to cool the cathode intake air. In this utility model, the fuel cell is directly communicated with the stack cooling system to cool the discharged refrigerant flow, which causes a certain degree of energy waste. Summary of the Utility Model

[0005] The utility model provides a waste heat recovery system for a hydrogen fuel cell, aiming to solve the problem that the waste heat generated during the operation of a hydrogen fuel cell cannot be effectively utilized during the electric energy conversion process, resulting in energy waste.

[0006] To solve the above technical problems, the present utility model proposes a hydrogen fuel cell waste heat recovery system, which includes a hydrogen fuel cell and a hydrogen purification device. The hydrogen inlet of the hydrogen fuel cell is connected to the hydrogen purification device through a pipeline. The hydrogen purification device is connected to by-product hydrogen through a pipeline. The air inlet of the hydrogen fuel cell is connected to air through a pipeline. The waste gas outlet of the hydrogen fuel cell discharges waste gas through a pipeline. The water outlet of the hydrogen fuel cell is connected to the hot water inlet of a heat exchanger through a pipeline. The hot water outlet of the heat exchanger is sequentially connected to the water inlet of a circulating pump and an air cooler through pipelines. The water outlet of the air cooler is connected to the water inlet of the hydrogen fuel cell through a pipeline.

[0007] Further, desalted water is introduced into the desalted water inlet of the heat exchanger through a pipeline. A first regulating valve is provided on the pipeline through which the heat exchanger is connected to the desalted water. The desalted water outlet of the heat exchanger is also connected to the water inlet of a deaerator through a pipeline. A branch pipeline is provided in front of the first regulating valve on the pipeline through which the heat exchanger is connected to the desalted water. The branch pipeline is connected to the pipeline through which the heat exchanger is connected to the deaerator, and a second regulating valve is provided on the branch pipeline.

[0008] Further, the feed water outlet of the deaerator is connected to the inlet of a feed water pump through a pipeline. The outlet of the feed water pump is connected to the feed water inlet of a boiler through a pipeline. The main steam outlet of the boiler is connected to the main steam inlet of a back pressure turbine through a pipeline. The exhaust steam outlet of the back pressure turbine is connected to an external heat supply pipeline through one pipeline and to the deaerating steam inlet of the deaerator through the other pipeline.

[0009] Further, the output shaft of the back pressure turbine is connected to a generator. The power interface of the generator is connected to the plant power system through a power cable.

[0010] Further, the power interface of the hydrogen fuel cell is connected to a connection module through a power cable. The connection module is respectively connected to an energy storage unit and a power conditioning unit. The power conditioning unit is connected to the plant power system through a power cable.

[0011] Further, the heat exchanger is a plate heat exchanger.

[0012] Further, the hydrogen fuel cell is a set of parallel-connected battery packs.

[0013] Compared with the prior art, the present utility model has the following technical effects:

[0014] 1. By setting a heat exchanger, the present utility model utilizes the waste heat generated during the operation of the hydrogen fuel cell in the thermal system of a thermal power plant, enabling cascaded utilization of energy and effectively improving the energy utilization efficiency.

[0015] 2. By setting the regulating valve, the utility model can adjust the flow rate of demineralized water entering the heat exchanger, achieving the effect of controlling the inlet temperature of water in the hydrogen fuel cell. The air cooler can be used as a backup under extreme working conditions.

[0016] 3. The utility model utilizes industrial by-product hydrogen through a hydrogen fuel cell for utilization in a heat supply unit, which can reduce the coal consumption of the unit, and the power generation of the hydrogen fuel cell can be used as a supplement to the plant electricity of the back-pressure unit.

[0017] 4. By setting a power regulation unit to dispatch the output power of the hydrogen fuel cell, the utility model can obtain a more stable power output. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of the hydrogen fuel cell waste heat recovery system according to an embodiment of the utility model.

[0019] Reference numerals: 1, hydrogen fuel cell; 2, hydrogen purification device; 3, heat exchanger; 4, circulation pump; 5, air cooler; 6, first regulating valve; 7, deaerator; 8, second regulating valve; 9, feed water pump; 10, boiler; 11, back-pressure machine; 12, generator; 13, plant electricity system; 14, connection module; 15, energy storage unit; 16, power regulation unit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] To make the objectives, technical solutions, and advantages of the utility model clearer, the technical solutions of the utility model will be clearly and completely described below in conjunction with specific embodiments of the present application and with reference to the accompanying drawings.

[0021] In the original process, the water outlet of the hydrogen fuel cell is connected to the air cooler, directly cooling the waste heat during the operation of the hydrogen fuel cell through the air, resulting in waste of energy. Therefore, this embodiment provides a hydrogen fuel cell waste heat recovery system. Refer to Figure 1 As shown, it includes a hydrogen fuel cell 1 and a hydrogen purification device 2. The hydrogen inlet of the hydrogen fuel cell 1 is connected to the hydrogen purification device 2 through a pipeline. The hydrogen purification device 2 is connected to by-product hydrogen through a pipeline. The air inlet of the hydrogen fuel cell 1 is connected to air through a pipeline. The waste gas outlet of the hydrogen fuel cell 1 discharges waste gas through a pipeline. The water outlet of the hydrogen fuel cell 1 is connected to the hot water inlet of the heat exchanger 3 through a pipeline. The hot water outlet of the heat exchanger 3 is sequentially connected to the water inlet of the circulation pump 4 and the air cooler 5 through a pipeline. The water outlet of the air cooler 5 is connected to the water inlet of the hydrogen fuel cell 1 through a pipeline.

[0022] Desalted water is introduced into the desalted water inlet of the heat exchanger 3 through a pipeline. A first regulating valve 6 is provided on the pipeline through which the desalted water enters the heat exchanger 3. The desalted water outlet of the heat exchanger 3 is also connected to the water inlet of the deaerator 7 through a pipeline. A branch pipeline is provided in front of the first regulating valve 6 on the pipeline through which the desalted water enters the heat exchanger 3. The branch pipeline is connected to the pipeline connecting the heat exchanger 3 and the deaerator 7, and a second regulating valve 8 is provided on the branch pipeline.

[0023] The water supply outlet of the deaerator 7 is connected to the inlet of the feed water pump 9 through a pipeline. The outlet of the feed water pump 9 is connected to the feed water inlet of the boiler 10 through a pipeline. The main steam outlet of the boiler 10 is connected to the main steam inlet of the back pressure turbine 11 through a pipeline. The exhaust steam outlet of the back pressure turbine 11 is connected to the external heating pipeline through one pipeline and to the deaeration steam inlet of the deaerator 7 through the other pipeline.

[0024] The output shaft of the back pressure turbine 11 is connected to the generator 12 for power generation. The power interface of the generator 12 is connected to the plant power system 13 through a power cable.

[0025] The power interface of the hydrogen fuel cell 1 is connected to the connection module 14 through a power cable. The connection module 14 is respectively connected to the energy storage unit 15 and the power conditioning unit 16. The power conditioning unit 16 is connected to the plant power system 13 through a power cable.

[0026] Further, the heat exchanger 3 can be a plate heat exchanger.

[0027] Further, the hydrogen fuel cell 1 can be a set of parallel-connected battery packs.

[0028] The working principle of the present utility model:

[0029] The by-product hydrogen and air after passing through the hydrogen purification device 2 enter the hydrogen fuel cell 1 through a pipeline to react, generating electricity and hot water, and the waste gas is discharged through a pipeline. The electricity can be used as a supplement to the plant power of the heating unit. The hot water heats a part of the desalted water through the heat exchanger 3, and the cooled hot water then enters the hydrogen fuel cell 1 through the circulation pump 4.

[0030] When the temperature of the hot water cooled by the heat exchanger 3 is higher than the maximum allowable temperature of the hydrogen fuel cell 1, the air cooler 5 is started to reduce the hot water temperature to the allowable temperature of the hydrogen fuel cell 1 and then enter the hydrogen fuel cell 1 to ensure the safe operation of the hydrogen fuel cell 1.

[0031] Through the flow control of the first regulating valve 6 and the second regulating valve 8, the desalted water is divided into two parts. One part enters the heat exchanger 3 for heating, and the other part passes through the bypass. The two parts of the desalted water are mixed and then enter the deaerator 7.

[0032] The boiler 10 generates steam to drive the back pressure turbine 11 to do work, and then drives the generator 12 to generate electricity. The exhaust steam of the back pressure turbine 11 is used for external heating in one way and enters the deaerator 7 in the other way. The saturated water in the deaerator 7 is transported to the boiler 10 through the feed water pump 9 to be heated to generate steam, completing a cycle.

[0033] The power regulation unit 16 can adjust the output electric power of the hydrogen fuel cell 1 according to the demand, and perform energy management and power scheduling for the hydrogen fuel cell 1 and the energy storage unit 15. The electricity output by the hydrogen fuel cell 1 is incorporated into the plant power system 13 together with the generator 12 after the scheduling management of the power regulation unit 16.

[0034] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the creative concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A waste heat recovery system for a hydrogen fuel cell, comprising a hydrogen fuel cell (1) and a hydrogen purification device (2), wherein the hydrogen inlet of the hydrogen fuel cell (1) is connected to the hydrogen purification device (2) through a pipeline, the hydrogen purification device (2) is fed with byproduct hydrogen through a pipeline, the air inlet of the hydrogen fuel cell (1) is fed with air through a pipeline, and the exhaust gas outlet of the hydrogen fuel cell (1) discharges exhaust gas through a pipeline, characterized in that: The water outlet of the hydrogen fuel cell (1) is connected to the hot water inlet of the heat exchanger (3) through a pipeline, the hot water outlet of the heat exchanger (3) is connected to the water inlet of the circulation pump (4) and the air cooler (5) in sequence through pipelines, and the water outlet of the air cooler (5) is connected to the water inlet of the hydrogen fuel cell (1) through a pipeline.

2. A hydrogen fuel cell waste heat recovery system according to claim 1, characterized in that: Desalted water is introduced into the desalted water inlet of the heat exchanger (3) through a pipeline, a first regulating valve (6) is provided on the pipeline through which the desalted water is introduced into the heat exchanger (3), the desalted water outlet of the heat exchanger (3) is also connected to the water inlet of the deaerator (7) through a pipeline, a branch pipeline is provided in front of the first regulating valve (6) on the pipeline through which the desalted water is introduced into the heat exchanger (3), the branch pipeline is connected to the pipeline connecting the heat exchanger (3) and the deaerator (7), and a second regulating valve (8) is provided on the branch pipeline.

3. A hydrogen fuel cell waste heat recovery system according to claim 2, characterized in that: The feed water outlet of the deaerator (7) is connected to the inlet of the feed water pump (9) through a pipeline, the outlet of the feed water pump (9) is connected to the feed water inlet of the boiler (10) through a pipeline, the main steam outlet of the boiler (10) is connected to the main steam inlet of the back pressure machine (11) through a pipeline, and the exhaust steam outlet of the back pressure machine (11) is connected to the external heating pipeline and the deoxygenated steam inlet of the deaerator (7) through a pipeline.

4. A hydrogen fuel cell waste heat recovery system according to claim 3, characterized in that: The output shaft of the back pressure machine (11) is connected to a generator (12), and the power interface of the generator (12) is connected to a factory power system (13) via a power cable.

5. A hydrogen fuel cell waste heat recovery system according to claim 1, characterized in that: The power interface of the hydrogen fuel cell (1) is connected to a connection module (14) via a power cable, the connection module (14) is respectively connected to an energy storage unit (15) and a power regulation unit (16), and the power regulation unit (16) is connected to a factory power system (13) via a power cable.

6. A hydrogen fuel cell waste heat recovery system according to claim 1, characterized in that: The heat exchanger (3) is a plate heat exchanger.

7. A hydrogen fuel cell waste heat recovery system according to claim 1, characterized in that: The hydrogen fuel cell (1) is a set of parallel-connected battery packs.

Images