A hydrogen production system with air cooling and waste heat recovery system

Abstract

The utility model discloses a same side heat exchange hydrogen production system with air cooling and waste heat recovery system belongs to hydrogen production system technical field, including high pressure steam pipeline, high pressure steam pipeline one end is connected outside steam source, and the other end is connected gas mixer, anode entrance connects air heater, and air heater connects anode heat exchanger, and the first medium side one end of anode heat exchanger is connected air heater, and the other end is connected cathode cooler. Through the external supply water vapor, need not set up steam generator in the system, through the cathode tail gas, anode tail gas carries out two step preheating to air, reduces the load of air heater, and the heat of cathode tail gas reduces also can reduce the load of condenser after cathode tail gas passes two step heat exchange, part cathode tail gas is introduced into hydrogen production system again, can guarantee having hydrogen in mixed gas again, can introduce part water vapor, reduces the supply amount of external water vapor, has reduced energy loss as far as possible.

Description

Technical Field

[0001] This utility model belongs to the technical field of hydrogen production systems, specifically relating to a same-side heat exchange hydrogen production system with air cooling and waste heat recovery systems. Background Technology

[0002] The statements in this section are merely background information related to this utility model and do not necessarily constitute prior art.

[0003] Hydrogen production systems using water electrolysis generally require steam as the electrolysis feedstock. In the past, most water electrolysis hydrogen production systems used a liquid water architecture, employing a single liquid water source and heating the water through a steam generator to generate steam to supply the fuel cell reactor. The steam generator required external energy.

[0004] To address the aforementioned issues, existing technology discloses an adaptive, energy-saving SOEC water electrolysis hydrogen production system. This system includes a water preheater, a steam generator, an ejector, and a steam preheater installed on the steam pipeline. The exhaust gas from the anode outlet of the SOEC electrolysis cell stack passes through an air preheater and a water preheater for heat exchange before being discharged to the external environment. The ejector's hydrogen inlet draws in 5% volumetric flow rate of ambient-temperature hydrogen from the hydrogen bypass. After thorough mixing of the steam and hydrogen in the ejector, the mixture enters a mixer for secondary mixing.

[0005] In the above scheme, the anode exhaust gas exchanges heat with liquid water through a water preheater to heat the liquid water and reduce the load on the steam generator. However, the following problems exist:

[0006] In the system architecture, the water vapor required for the reaction is provided by liquid water. Although relying on anode tail gas can reduce the load on the steam generator to some extent, the heat of the anode tail gas after heat exchange is limited when the system is running at high efficiency, and the load on the steam generator is still high. Using only anode tail gas to preheat the air results in a high load on the air heater. In addition, the cathode tail gas still has a high amount of residual heat after exchanging heat with the fuel gas. When the water vapor in the cathode tail gas is cooled into water by passing through the water cooler, it will increase the load on the water cooler. Utility Model Content

[0007] To address the aforementioned issues, this invention provides a hydrogen production system with a same-side heat exchanger and an air cooling and waste heat recovery system. The system architecture is changed from the traditional liquid water-to-steam supply architecture to an external steam supply architecture, with most of the steam required for the reaction provided by a high-pressure steam pipeline. This eliminates the need for a separate steam generator within the system, ensuring sufficient steam supply for system operation. Two-step preheating of the air using cathode and anode tail gas reduces the load on the air heater. Simultaneously, the reduced heat of the cathode tail gas after the two-step heat exchange also lowers the load on the condenser. A medium-temperature circulation method is used to reintroduce some of the cathode tail gas into the hydrogen production system, ensuring the presence of hydrogen in the mixed fuel gas while introducing some steam, reducing the external steam supply and minimizing energy loss.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A same-side heat exchange hydrogen production system with air cooling and waste heat recovery system includes an electric stack, which has an anode and a cathode. The cathode has a cathode inlet and a cathode outlet, and the anode has an anode inlet and an anode outlet. It also includes a high-pressure steam pipeline, one end of which is connected to an external steam source and the other end of which is connected to a gas mixer.

[0010] The anode inlet is connected to an air heater, which is connected to an anode heat exchanger. The anode heat exchanger has a first medium side and a first heat exchange side. One end of the first medium side is connected to the air heater, and the other end is connected to the cathode cooler. One end of the first heat exchange side is connected to the anode outlet of the fuel cell stack, and the other end is connected to the tailpipe.

[0011] The cathode cooler has a second medium side and a second heat exchange side. One end of the second medium side is connected to the first medium side, and the other end is connected to the output end of the air fan. One end of the second heat exchange side is connected to the cathode heat exchanger, and the other end is connected to the distributor.

[0012] Preferably, the gas mixer has three gas inlets and one gas outlet, with a high-pressure steam line connected to the first gas inlet of the gas mixer.

[0013] Preferably, the cathode inlet is connected to a gas heater, and the gas heater is connected to a cathode heat exchanger.

[0014] Preferably, the cathode heat exchanger has a third medium side and a third heat exchange side, with one end of the third medium side connected to a gas heater and the other end connected to the gas outlet of a gas mixer.

[0015] Preferably, one end of the third heat exchange side is connected to the cathode outlet, and the other end is connected to one end of the second heat exchange side.

[0016] Preferably, the diverter has one diverter inlet and two diverter outlets, one of which is connected to a circulation pump.

[0017] Preferably, one end of the circulating pump is connected to a distributor, and the other end is connected to the third gas inlet of the first gas mixer.

[0018] Preferably, another branch outlet of the distributor is connected to a condenser, which is connected to a gas-liquid separator, which is connected to a hydrogen storage tank and a water tank, respectively.

[0019] Preferably, an anode cooler is added between the anode heat exchanger and the tailpipe.

[0020] Preferably, the anode cooler has a fourth medium side and a fourth heat exchange side. One end of the fourth medium side is connected to a liquid water pipeline, and the other end is connected to the third gas inlet of the gas mixer. One end of the fourth heat exchange side is connected to the first heat exchange side, and the other end is connected to the tailpipe.

[0021] Compared with the prior art, the advantages and positive effects of this utility model are:

[0022] In this invention, the hydrogen production system architecture is changed from the traditional liquid water-to-steam supply architecture to an architecture with direct external steam supply. Most of the steam required for the reaction is provided by high-pressure steam pipelines. There is no need to install a steam generator in the system, ensuring sufficient steam supply and operation. The air is preheated in two steps through cathode and anode tail gas, reducing the load on the air heater. At the same time, the reduced heat of the cathode tail gas after the two-step heat exchange also reduces the load on the condenser. By adopting a medium-temperature circulation method, some of the cathode tail gas is reintroduced into the hydrogen production system, which ensures that hydrogen is present in the mixed fuel gas and introduces some steam, reducing the external steam supply and minimizing energy loss. Attached Figure Description

[0023] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0024] Figure 1 This is a schematic diagram of the hydrogen production system according to Embodiment 1 of this utility model;

[0025] Figure 2 This is a schematic diagram of the hydrogen production system according to Embodiment 2 of this utility model;

[0026] In the picture:

[0027] 1. Fuel cell stack; 2. High-pressure steam pipeline; 3. Gas mixer; 4. Air heater; 5. Anode heat exchanger; 6. Air fan; 7. Cathode cooler; 8. Gas heater; 9. Cathode heat exchanger; 10. Diverter; 11. Circulating pump; 12. Condenser; 13. Gas-liquid separator; 14. Water tank; 15. Anode cooler. Detailed Implementation

[0028] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0029] The present invention will now be described in detail with reference to the accompanying drawings.

[0030] Example 1

[0031] This embodiment discloses a same-side heat exchange hydrogen production system with air cooling and waste heat recovery systems, such as... Figure 1 As shown, the system includes a fuel cell stack 1, which has a fuel cell anode and a fuel cell cathode. The fuel cell cathode has a cathode inlet and a cathode outlet, and the fuel cell anode has an anode inlet and an anode outlet. The anode side of the system is an air path, and the cathode side is a fuel gas path. The fuel gas mainly consists of high-temperature water vapor and hydrogen. The gas that actually participates in the reaction is high-temperature steam. The presence of hydrogen is to prevent the fuel cell stack from being oxidized when the temperature is too high.

[0032] Specifically, air at a set temperature is introduced into the anode inlet to provide heat energy to the fuel cell stack 1, ensuring that the fuel cell stack 1 can carry out electrochemical reactions normally; a mixture of hydrogen and water vapor is introduced into the cathode inlet. The water vapor undergoes an electrochemical reaction in the fuel cell stack 1, and the oxygen produced is discharged from the anode outlet along with the air as anode tail gas. The hydrogen produced and the unreacted water vapor are discharged from the cathode outlet as cathode tail gas. Both the anode tail gas and the cathode tail gas have high temperatures and contain abundant heat energy.

[0033] It also includes a high-pressure steam pipeline 2 located on the cathode side of the fuel cell stack. One end of the high-pressure steam pipeline 2 is connected to an external steam source, and the other end is connected to a gas mixer 3. The function of the high-pressure steam pipeline 2 is to provide the system with a large amount of high-temperature steam required for the reaction.

[0034] It should be explained that a gas mixer is a device used to mix two or more gases, typically consisting of a mixing chamber and multiple gas inlets / outlets. In this embodiment, the gas mixer 3 has three gas inlets and one gas outlet.

[0035] In this embodiment, the architecture of the hydrogen production system is changed from the traditional liquid water architecture to a steam architecture, and most of the steam required for the reaction is provided by the high-pressure steam pipeline 2.

[0036] In this embodiment, the water vapor consists of two parts: one part is the externally supplied steam source provided by the high-pressure steam pipeline 2; the second part is the water vapor in the circulating gas supplied by the cathode. The two sources of gas serve two purposes: firstly, to ensure a sufficient supply of water vapor to the hydrogen production system, thereby guaranteeing its efficient operation; and secondly, considering that the cathode exhaust gas in the hydrogen production system contains water vapor, rationally utilizing and recycling the water vapor in the cathode exhaust gas can reduce the introduction of external water vapor and reduce energy loss.

[0037] like Figure 1 As shown, in this embodiment, the first gas inlet of the gas mixer 3 is connected to the high-pressure steam pipeline 2, and the cathode exhaust gas provided by the cathode enters the second gas inlet of the gas mixer 3; the gas mixer 3 can fully mix the water vapor and the cathode exhaust gas.

[0038] Understandably, the third gas inlet is closed at this time.

[0039] Specifically, such as Figure 1 As shown, on the anode side of the fuel cell stack 1, the anode inlet is connected to an air heater 4, the air heater 4 is connected to an anode heat exchanger 5, the anode heat exchanger 5 has a first medium side and a first heat exchange side, one end of the first medium side is connected to the air heater 4, and the other end is connected to the cathode cooler 7.

[0040] The cathode cooler 7 has a second medium side and a second heat exchange side. One end of the second medium side is connected to the first medium side, and the other end is connected to the output end of the air fan 6. One end of the first heat exchange side is connected to the anode outlet of the fuel cell stack 1, and the other end is connected to the tailpipe.

[0041] Understandably, the air blower 6 sends air into the cathode cooler 7 for preliminary preheating. The preheated air then enters the anode heat exchanger 5 for a second heat exchange with the anode exhaust gas, further increasing its temperature. The air then enters the air heater 4 for heating. After being heated to the set temperature, the air is sent into the fuel cell stack 1 and becomes the anode exhaust gas. It then enters the first heat exchange side of the anode heat exchanger 5 for further preheating before being discharged through the tailpipe. By preheating the air in two steps, the heating load on the air heater is reduced.

[0042] In this embodiment, the air heater 4 can specifically be an electric heater; in other embodiments, it can also be selected as a fuel heater as needed. The air blower 6 can specifically be an air compressor, used to compress air and deliver it to the air heater 4.

[0043] like Figure 1As shown, on the cathode side of the fuel cell stack 1, the cathode inlet is connected to the gas heater 8, the gas heater 8 is connected to the cathode heat exchanger 9, the cathode heat exchanger 9 has a third medium side and a third heat exchange side, one end of the third medium side is connected to the gas heater 8, and the other end is connected to the gas outlet of the gas mixer 3; one end of the third heat exchange side is connected to the cathode outlet, and the other end is connected to one end of the second medium side, and the other end of the second medium side is connected to the distributor 10.

[0044] In this embodiment, the gas heater 8 can be an electric heater. In other embodiments, it can also be selected as a fuel heater as needed.

[0045] Understandably, the mixed gas in the gas mixer 3 enters the third medium side, exchanges heat with the cathode tail gas in the third heat exchange side, and then passes through the gas heater 8. After being heated to the set temperature, it enters the fuel cell 1 through the cathode inlet and reacts. After the reaction, cathode tail gas containing water vapor and hydrogen is formed. The cathode tail gas exits from the cathode outlet and then enters the third heat exchange side to preheat the mixed gas from the gas mixer 3. The cathode tail gas, which still has residual heat, enters the second heat exchange side to preheat the air passing through it for the first time. After that, the cathode tail gas enters the splitter 10.

[0046] The splitter 10 has one split inlet and two split outlets, one of which is connected to the circulation pump 11. One end of the circulation pump 11 is connected to the splitter 10, and the other end is connected to the second gas inlet of the gas mixer 3. The circulation pump 11 is used to send some water vapor and hydrogen into the gas mixer 3, mix them with the water vapor provided by the high-pressure steam pipeline 2, and then enter the fuel cell stack 1 to participate in the reaction after heat exchange and heating.

[0047] Under normal circumstances, the condenser converts gas or vapor into liquid and quickly transfers the heat in the tubes to the air near the tubes. The condenser operation is an exothermic process, so the condenser temperature is relatively high and an exhaust fan is needed for heat dissipation.

[0048] Understandably, the cathode exhaust gas undergoes two-step heat exchange with the mixed combustion gas and air. The cathode exhaust gas entering the splitter 10 has a lower temperature than the cathode exhaust gas that only exchanges heat with the mixed combustion gas. After two heat exchanges (cooling), the cathode exhaust gas flows through the condenser and gas-liquid separator. The temperature of the condenser is lower than that of the cathode exhaust gas that only undergoes one heat exchange, thereby reducing the power consumption of the condenser exhaust fan.

[0049] In the hydrogen production system architecture of this embodiment, after the cathode tail gas is heated by the cathode heat exchanger 9 to heat the mixed gas, the cathode tail gas, which still has residual heat, enters the cathode cooler 7 to heat the air. Then, a portion is separated by the splitter 10 and recycled to the gas mixer 3. The residual heat of the cathode tail gas is fully utilized, reducing the heating load of the air heater.

[0050] The cathode exhaust gas contains water vapor and hydrogen, which mixes with the water vapor in the high-pressure steam pipeline 2 and is then circulated into the gas mixer 3. This means that some of the steam and hydrogen can be recycled into the hydrogen production system. A medium-temperature cycle is used, and the gas recycled back from the cathode is a mixture of steam and hydrogen. This reduces the amount of water vapor supplied by the high-pressure steam pipeline 2 and provides hydrogen for the mixed gas, preventing the fuel cell stack from being oxidized at excessively high temperatures. There is no need to draw a separate pipeline from the hydrogen storage tank to mix it separately with the water vapor.

[0051] like Figure 1 As shown, another branch outlet of the splitter 10 is connected to the condenser 12. The condenser 12 cools the cathode tail gas flowing through it, and the water vapor in it forms water. The condenser 12 is connected to the gas-liquid separator 13, which is connected to the hydrogen storage tank and the water tank 14 respectively. The gas-liquid separator 13 is used to separate hydrogen and water in the cathode tail gas flowing through it. The separated hydrogen is sent to the hydrogen storage tank for storage, and the water is sent to the water tank 14.

[0052] Working principle:

[0053] During system operation, air passes sequentially through air fan 6, cathode cooler, anode heat exchanger, and air heater before entering fuel cell stack 1. In this process, the air undergoes three steps: cathode tail gas preheating, anode tail gas preheating, and heating. The phased preheating in the first two steps reduces the heating load of the air heater and effectively utilizes the waste heat of the tail gas in the hydrogen production system.

[0054] The mixed gas enters the fuel cell stack 1 through the cathode heat exchanger 9 and the gas heater 8 in sequence. When the mixed gas passes through the cathode heat exchanger 9, it exchanges heat with the cathode exhaust gas of the fuel cell stack 1. At this time, the mixed gas enters the gas heater 8 after preheating. The gas heater 8 heats the mixed gas a second time to the set temperature, so that the temperature of the mixed gas reaches the temperature requirement for entering the fuel cell stack 1.

[0055] After the mixed gas is discharged from the cathode outlet of the fuel cell stack 1, it becomes high-temperature cathode tail gas. The cathode tail gas exits from the cathode outlet and is preheated by the cathode heat exchanger 9. The cathode tail gas, which still has residual heat, enters the cathode cooler 7 to preheat the air, and then enters the distributor 10. A portion of the cathode tail gas is sent to the gas mixer 3 through the circulation pump 11 to mix with the water vapor in the high-pressure steam pipeline 2. After heat exchange and heating, it re-enters the fuel cell stack 1 to participate in the reaction.

[0056] In this embodiment, the architecture of the hydrogen production system is changed from the traditional architecture of generating water vapor from liquid water to an architecture of direct external water vapor supply. Most of the water vapor required for the reaction is provided by high-pressure steam pipelines; there is no need to set up a steam generator in the system, thereby ensuring that the system has sufficient steam supply and ensuring the operation of the system.

[0057] Furthermore, by installing a cathode cooler on the cathode side, the air is preheated in the first step using the cathode exhaust gas, and then preheated in the second step using the anode heat exchanger. This reduces the heating load on the air heater and effectively utilizes the waste heat from the exhaust gas in the hydrogen production system. Reintroducing some of the cathode exhaust gas into the hydrogen production system ensures the presence of hydrogen in the mixed fuel gas while also introducing some water vapor, reducing the external water vapor supply and minimizing energy loss.

[0058] Example 2

[0059] The hydrogen production system with air cooling and waste heat recovery system disclosed in this embodiment has the same main structural composition as the hydrogen production system with air cooling and waste heat recovery system disclosed in Embodiment 1, the difference being:

[0060] like Figure 2 As shown, an anode cooler 15 is added between the anode heat exchanger 5 and the tailpipe. The anode cooler 15 has a fourth medium side and a fourth heat exchange side. One end of the fourth medium side is connected to the liquid water pipeline, and the other end is connected to the third gas inlet of the gas mixer 3. One end of the fourth heat exchange side is connected to the first heat exchange side, and the other end is connected to the tailpipe.

[0061] In this embodiment, by setting up an anode cooler 15, the waste heat of the anode tail gas is further utilized. The liquid water on the fourth medium side of the anode cooler 15 is heated by the anode tail gas to a superheated steam state, becoming water vapor, which serves as one of the steam sources for the hydrogen production system and is connected to the gas mixer 3. This not only reduces the emission temperature of the anode tail gas, increasing system safety, but also further utilizes the waste heat of the anode tail gas, while simultaneously reducing the amount of water vapor supplied in the high-pressure steam pipeline.

[0062] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. A same-side heat exchange hydrogen production system with air cooling and waste heat recovery system, comprising a fuel cell stack, the fuel cell stack having a fuel cell anode and a fuel cell cathode, the fuel cell cathode having a cathode inlet and a cathode outlet, and the fuel cell anode having an anode inlet and an anode outlet; characterized in that, It also includes a high-pressure steam pipeline, one end of which is connected to an external steam source and the other end to a gas mixer; The anode inlet is connected to an air heater, which is connected to an anode heat exchanger. The anode heat exchanger has a first medium side and a first heat exchange side. One end of the first medium side is connected to the air heater, and the other end is connected to the cathode cooler. One end of the first heat exchange side is connected to the anode outlet of the fuel cell stack, and the other end is connected to the tailpipe. The cathode cooler has a second medium side and a second heat exchange side. One end of the second medium side is connected to the first medium side, and the other end is connected to the output end of the air fan. One end of the second heat exchange side is connected to the cathode heat exchanger, and the other end is connected to the distributor.

2. The same-side heat exchange hydrogen production system with air cooling and waste heat recovery system as described in claim 1, characterized in that, The gas mixer has three gas inlets and one gas outlet, with a high-pressure steam line connected to the first gas inlet of the gas mixer.

3. The same-side heat exchange hydrogen production system with air cooling and waste heat recovery system as described in claim 1, characterized in that, The cathode inlet is connected to a gas heater, and the gas heater is connected to a cathode heat exchanger.

4. A same-side heat exchange hydrogen production system with air cooling and waste heat recovery system as described in claim 3, characterized in that, The cathode heat exchanger has a third medium side and a third heat exchange side. One end of the third medium side is connected to a gas heater, and the other end is connected to the gas outlet of a gas mixer.

5. A same-side heat exchange hydrogen production system with air cooling and waste heat recovery system as described in claim 4, characterized in that, One end of the third heat exchange side is connected to the cathode outlet, and the other end is connected to one end of the second heat exchange side.

6. A same-side heat exchange hydrogen production system with air cooling and waste heat recovery system as described in claim 1, characterized in that, The diverter has one diverting inlet and two diverting outlets, one of which is connected to a circulating pump.

7. A same-side heat exchange hydrogen production system with air cooling and waste heat recovery system as described in claim 6, characterized in that, One end of the circulating pump is connected to the distributor, and the other end is connected to the third gas inlet of the first gas mixer.

8. A same-side heat exchange hydrogen production system with air cooling and waste heat recovery system as described in claim 6, characterized in that, The other branch outlet of the distributor is connected to a condenser, which is connected to a gas-liquid separator, which is connected to a hydrogen storage tank and a water tank, respectively.

9. A same-side heat exchange hydrogen production system with air cooling and waste heat recovery system as described in claim 1, characterized in that, An anode cooler is added between the anode heat exchanger and the tailpipe.

10. A same-side heat exchange hydrogen production system with air cooling and waste heat recovery system as described in claim 9, characterized in that, The anode cooler has a fourth medium side and a fourth heat exchange side. One end of the fourth medium side is connected to a liquid water pipeline, and the other end is connected to the third gas inlet of the gas mixer. One end of the fourth heat exchange side is connected to the first heat exchange side, and the other end is connected to the tailpipe.

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