Hydrogen production system with liquid water cooling and same-side heat exchange

Abstract

This utility model discloses a hydrogen production system with liquid water cooling and a single-sided heat exchange, belonging to the technical field of hydrogen production systems. It includes a high-pressure steam pipeline connected to a first gas mixer; an anode inlet connected to an air heater, which in turn connects 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 output end of an air blower. One end of the first heat exchange side is connected to the anode outlet, and the other end is connected to a first cooler. The first cooler has a second medium side and a second heat exchange side. One end of the second heat exchange side is connected to the first heat exchange side, and the other end is connected to a tailpipe. One end of the second medium side is connected to liquid water, and the other end is connected to the first gas mixer. By supplying steam externally, there is no need to install a steam generator within the system, ensuring sufficient steam supply. By installing the first cooler, the liquid water is heated to generate steam, reducing the need for external steam supply.

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 liquid water cooling. 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.

[0004] To address the aforementioned issues, existing technology discloses an electrolytic water hydrogen production system. An evaporative heat exchanger is installed between a water tank and a steam heater. The evaporative heat exchanger is connected to the cathode outlet of the fuel cell stack and an air heat exchanger. After entering the evaporative heat exchanger, liquid water can exchange heat with the anode tail gas and vaporize into water vapor. The cathode tail gas is separated into water and hydrogen in a steam separator, and the hydrogen is finally transported to a hydrogen storage tank.

[0005] In the above scheme, the anode exhaust gas exchanges heat with liquid water through an evaporative heat exchanger, causing the liquid water to vaporize into water vapor, thus replacing the steam generator and reducing system costs; however, the following problems exist:

[0006] In the system architecture, the water vapor required for the reaction is entirely heated by the anode tail gas. However, the heat of the anode tail gas is limited, which results in a limited water vapor production and restricts the operation of the system. The anode tail gas cross-heating, which heats the liquid water first and then preheats the air, is inefficient and increases the burden on the air heater. In addition, in the above scheme, the gas circulation of the cathode tail gas adopts a low-temperature cycle, and only a portion of the hydrogen is ultimately recycled into the hydrogen production system. Utility Model Content

[0007] To address the aforementioned issues, this invention provides a hydrogen production system with liquid water cooling on the same side of the heat exchanger. The system architecture is changed from the traditional liquid water-to-steam supply architecture to an externally supplied steam 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. By installing a first cooler on the anode side, some liquid water is heated using anode tail gas to generate steam, reducing the external steam supply. This further optimizes the utilization of the heat (waste heat) from the anode tail gas while lowering its discharge temperature, increasing system safety. Furthermore, by reintroducing some of the cathode tail gas after heat exchange with the mixed fuel gas into the hydrogen production system, the presence of hydrogen in the mixed fuel gas is ensured, and some steam is introduced, further 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 hydrogen production system with liquid water cooling and same-side heat exchange 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 first gas mixer.

[0010] The anode inlet is connected to an air heater, and the air heater 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 air fan output. One end of the first heat exchange side is connected to the anode outlet, and the other end is connected to the first cooler.

[0011] The first cooler has a second medium side and a second heat exchange side. One end of the second heat exchange side is connected to the first heat exchange side, and the other end is connected to the tailpipe. One end of the second medium side is connected to the liquid water pipe, and the other end is connected to the first gas mixer.

[0012] Preferably, the first gas mixer has three gas inlets and one gas outlet, a high-pressure steam pipeline is connected to the first gas inlet of the first gas mixer, and the second medium side is connected to the second gas inlet of the first gas mixer.

[0013] Preferably, the cathode inlet is connected to a gas heater, the gas heater is connected to a cathode heat exchanger, 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 the gas heater, and the other end is connected to the gas outlet of the first gas mixer.

[0014] Preferably, one end of the third heat exchange side is connected to the cathode outlet, and the other end is connected to the splitter.

[0015] Preferably, the distributor has one distributor inlet and two distributor outlets, one of which is connected to a circulation pump; one end of the circulation pump is connected to the distributor, and the other end is connected to the third gas inlet of the first gas mixer.

[0016] 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.

[0017] Preferably, a second cooler and a second gas mixer are added to the cathode side of the electrode.

[0018] Preferably, the second cooler has a fourth medium side and a fourth heat exchange side, and the second gas mixer has two inlets and one outlet.

[0019] Preferably, the second cooler is disposed between the cathode heat exchanger and the distributor, one end of the fourth medium side is connected to a liquid water pipeline, and the other end is connected to an inlet of the second gas mixer; one end of the fourth heat exchange side is connected to the third heat exchange side, and the other end is connected to the inlet of the distributor.

[0020] Preferably, the second gas mixer is disposed between the first cooler and the first gas mixer, and the outlet of the second gas mixer is connected to the second gas inlet of the first gas mixer; one end of the second medium side is connected to liquid water, and the other end is connected to another inlet of the second gas mixer.

[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 external steam supply architecture, with most of the steam required for the reaction provided by high-pressure steam pipelines. This eliminates the need for a separate steam generator within the system, ensuring sufficient steam supply for system operation. By installing a first cooler on the anode side, some liquid water is heated using anode tail gas to generate steam, reducing the external steam supply. This further optimizes the utilization of the anode tail gas's heat (waste heat) while lowering its discharge temperature, increasing system safety. By reintroducing some of the cathode tail gas after heat exchange with the mixed fuel gas into the hydrogen production system, the presence of hydrogen in the mixed fuel gas is ensured, and some steam is introduced, further 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. First gas mixer; 4. Air heater; 5. Anode heat exchanger; 6. Air fan; 7. First cooler; 8. Gas heater; 9. Cathode heat exchanger; 10. Diverter; 11. Circulating pump; 12. Condenser; 13. Gas-liquid separator; 14. Water tank; 15. Second cooler; 16. Second gas mixer. 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 liquid water cooling, 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 installed 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 the first 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 first 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 three parts: an externally supplied steam source provided by the high-pressure steam pipeline 2; water vapor generated by heating liquid water with heat provided by the anode tail gas; and water vapor from the circulating gas supplied by the cathode. These three sources of fuel gas serve two purposes: firstly, to ensure a sufficient supply of water vapor for the hydrogen production system, thereby guaranteeing its efficient operation; and secondly, to take into account the high waste heat generated by both the anode and cathode tail gases in the hydrogen production system, thus rationally utilizing this waste heat and minimizing energy loss.

[0037] like Figure 1 As shown, the first gas mixer 3 has three gas inlets and one gas outlet. The high-pressure steam pipeline 2 is connected to the first gas inlet of the first gas mixer 3. The water vapor provided by the anode enters the second gas inlet of the first gas mixer 3, and the cathode tail gas (containing unreacted water vapor and generated hydrogen) provided by the cathode enters the third gas inlet of the first gas mixer 3. The first gas mixer 3 is used to fully mix the three parts of water vapor and hydrogen.

[0038] 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 output end of an air blower 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 a first cooler 7.

[0039] The first cooler 7 has a second medium side and a second heat exchange side. One end of the second heat exchange side is connected to the first heat exchange side, and the other end is connected to the tailpipe. One end of the second medium side is connected to the liquid water pipe, and the other end is connected to the second gas inlet of the first gas mixer 3.

[0040] Understandably, the air blower 6 sends air into the first medium side of the anode heat exchanger 5 to exchange heat with the anode tail gas, thus preheating the air. After that, the air enters the air heater 4 and is heated to the set temperature before being sent into the fuel cell stack 1. Then, it becomes the anode tail gas and enters the first heat exchange side of the anode heat exchanger 5 to preheat the air and reduce the heating load on the air heater.

[0041] Subsequently, the still-warm anode exhaust gas reaches the second heat exchange side of the first cooler 7, heating the liquid water on the second medium side of the first cooler 7. This causes the liquid water to generate water vapor, while the anode exhaust gas is further cooled. The anode exhaust gas is then discharged from the system at a lower temperature, increasing system safety. The water vapor generated in the second medium side of the first cooler 7 flows into the first gas mixer 3 and mixes with the water vapor in the high-pressure steam pipeline 2.

[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 1 As shown, on the cathode side of the fuel cell stack 1, the cathode inlet is connected to a gas heater 8, and the gas heater 8 is connected to a 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 first gas mixer 3. One end of the third heat exchange side is connected to the cathode outlet, and the other end is connected to a distributor 10. In this embodiment, the gas heater 8 can specifically be an electric heater; in other embodiments, it can also be selected as a fuel heater as needed.

[0044] Understandably, the mixed gas in the first 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 first gas mixer 3. The cathode tail gas, which still has residual heat, then enters the distributor 10.

[0045] 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 third gas inlet of the first gas mixer 3. The circulation pump 11 is used to send part of the water vapor and hydrogen into the first gas mixer 3, mix them with the other two water vapor streams, and then enter the fuel cell stack 1 to participate in the reaction after heat exchange and heating.

[0046] In the hydrogen production system architecture of this embodiment, after the cathode tail gas is cooled, the gas temperature is still relatively high. Some of the steam and hydrogen are recycled together into the first gas mixer 3, that is, some of the steam and hydrogen can be recycled into the hydrogen production system. A medium-temperature cycle is adopted. The gas recycled back from the cathode is a mixture of steam and hydrogen. This cycle method can save the external steam supply and also save the heat required to heat the liquid water.

[0047] In addition, this circulation method can also provide hydrogen to the gas-fuel side of the circulation system, preventing the fuel cell stack from being oxidized when the temperature is too high; there is no need to draw a separate pipeline from the hydrogen storage tank to mix it separately with water vapor.

[0048] like Figure 1 As shown, another branch outlet of the splitter 10 is connected to the condenser 12. The condenser 12 cools the water vapor in the cathode tail gas flowing through it, causing it to form 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 the 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.

[0049] Working principle:

[0050] When the system is running, on the anode side of the fuel cell stack 1, air enters the fuel cell stack 1 through the air fan 6, the anode heat exchanger 5 and the air heater 4 in sequence. When the air passes through the anode heat exchanger 5, it exchanges heat with the anode exhaust gas of the fuel cell stack 1. At this time, the air enters the air heater 4 after being preheated. The air heater 4 heats the air a second time to the set temperature, so that the air temperature reaches the temperature requirement for entering the fuel cell stack 1.

[0051] After the air is discharged from the anode outlet of the fuel cell stack 1, it becomes high-temperature anode tail gas. The anode tail gas is preheated by the anode heat exchanger 5, and then the externally supplied liquid water is heated to a superheated steam state by the first cooler 7, so that it becomes water vapor and enters the system as one of the steam sources of the system.

[0052] It should be explained that the anode exhaust gas on the anode side still has a high temperature after preheating the air, so it can heat some of the liquid water to a superheated steam state.

[0053] After the first gas mixer 3 mixes the three parts of water vapor or hydrogen evenly, it passes through the cathode heat exchanger 9 and the gas heater 8 in sequence and enters the fuel cell stack 1. When the mixed gas passes through the cathode heat exchanger 9, it exchanges heat with the cathode tail 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.

[0054] 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 distributor 10. A portion of the cathode tail gas is sent to the first gas mixer 3 through the circulation pump 11 to mix with the other two streams of water vapor. After heat exchange and heating, it re-enters the fuel cell stack 1 to participate in the reaction.

[0055] 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.

[0056] In addition, by setting a first cooler on the anode side, the anode tail gas is used to heat part of the liquid water to generate water vapor, reducing the supply of some external water vapor. This further optimizes the utilization of the heat (waste heat) of the anode tail gas, while reducing the discharge temperature of the anode tail gas and increasing system safety.

[0057] Finally, by reintroducing a portion of the cathode tail gas after heat exchange with the mixed gas into the hydrogen production system, it is possible to ensure that the mixed gas contains hydrogen while also introducing some water vapor, thereby further reducing the external water vapor supply and minimizing energy loss.

[0058] Example 2

[0059] The hydrogen production system with liquid water cooling on the same side of the same side of the heat exchanger disclosed in this embodiment has the same main structural composition as the hydrogen production system with liquid water cooling on the same side of the heat exchanger disclosed in Embodiment 1, the difference being:

[0060] like Figure 2 As shown, a second cooler 15 and a second gas mixer 16 are added on the cathode side. The second cooler 15 has a fourth medium side and a fourth heat exchange side, and the second gas mixer 16 has two inlets and one outlet. Specifically, the second cooler 15 is disposed between the cathode heat exchanger and the distributor, and the second gas mixer 16 is disposed between the first cooler 7 and the first gas mixer 3. One end of the second heat exchange side of the first cooler 7 is connected to the first heat exchange side, and the other end is connected to the tailpipe. One end of the second medium side is connected to the liquid water pipe, and the other end is connected to one inlet of the second gas mixer 16.

[0061] One end of the fourth medium side of the second cooler 15 is connected to a liquid water pipeline, and the other end is connected to another inlet of the second gas mixer 16. One end of the fourth heat exchange side is connected to the third heat exchange side of the cathode heat exchanger, and the other end is connected to the inlet of the distributor 10. The outlet of the second gas mixer 16 is connected to the second gas inlet of the first gas mixer 3.

[0062] This embodiment uses both cathode and anode tail gas to heat liquid water simultaneously to generate steam. This approach may increase system complexity and is mainly used in higher-power hydrogen production systems, which will greatly save on steam source costs.

[0063] 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 hydrogen production system with liquid water cooling and in-line heat exchange, comprising an electrolyzer having an electrolyzer anode and an electrolyzer cathode, the electrolyzer cathode having a cathode inlet, a cathode outlet, the electrolyzer anode having an anode inlet, 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 is connected to the first 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 air fan output. One end of the first heat exchange side is connected to the anode outlet, and the other end is connected to the first cooler. The first cooler has a second medium side and a second heat exchange side, with one end of the second heat exchange side connected to the first heat exchange side and the other end connected to the tailpipe. The second medium side is connected to a liquid water pipeline at one end and to the first gas mixer at the other end.

2. The same-side heat exchange hydrogen production system with liquid water cooling as described in claim 1, characterized in that, The first gas mixer has three gas inlets and one gas outlet. A high-pressure steam pipeline is connected to the first gas inlet of the first gas mixer, and the second medium side is connected to the second gas inlet of the first gas mixer.

3. The same-side heat exchange hydrogen production system with liquid water cooling as described in claim 1, characterized in that, The cathode inlet is connected to a gas heater, which is connected to a cathode heat exchanger. 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 the gas heater, and the other end is connected to the gas outlet of the first gas mixer.

4. A hydrogen production system with liquid water cooling on the same side as described in claim 3, characterized in that, The third heat exchange side is connected to the cathode outlet at one end and to the splitter at the other end.

5. A hydrogen production system with liquid water cooling on the same side as described in claim 4, characterized in that, The splitter has one splitting inlet and two splitting outlets, one of which is connected to a circulation pump; one end of the circulation pump is connected to the splitter, and the other end is connected to the third gas inlet of the first gas mixer.

6. A hydrogen production system with liquid water cooling on the same side as described in claim 4, 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.

7. A hydrogen production system with liquid water cooling on the same side as described in claim 1, characterized in that, A second cooler and a second gas mixer are added to the cathode side of the electrode.

8. A hydrogen production system with liquid water cooling on the same side as described in claim 7, characterized in that, The second cooler has a fourth medium side and a fourth heat exchange side, and the second gas mixer has two inlets and one outlet.

9. A hydrogen production system with liquid water cooling on the same side as described in claim 7, characterized in that, The second cooler is located between the cathode heat exchanger and the distributor. One end of the fourth medium side is connected to a liquid water pipeline, and the other end is connected to an inlet of the second gas mixer. One end of the fourth heat exchange side is connected to the third heat exchange side, and the other end is connected to the inlet of the distributor.

10. A hydrogen production system with liquid water cooling on the same side as described in claim 7, characterized in that, The second gas mixer is disposed between the first cooler and the first gas mixer, and the outlet of the second gas mixer is connected to the second gas inlet of the first gas mixer; one end of the second medium side is connected to liquid water, and the other end is connected to another inlet of the second gas mixer.

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