Heat recovery system of methanol hydrogen production device

Abstract

The utility model discloses a heat recovery system of a methanol hydrogen production device. The heat recovery system comprises a reforming reactor, a pressure swing adsorber, a purifier and a heat exchanger, the reforming reactor, the pressure swing adsorber and the purifier are sequentially connected in series; the reforming reactor is provided with a methanol water inlet; the pressure swing adsorber is provided with an adsorber inlet, an adsorbed hydrogen outlet and a desorbed gas outlet; the device is characterized in that the heat exchanger is arranged in front of a methanol water inlet of the reforming reactor; the heat exchanger comprises a first heat exchanger, a second heat exchanger and a third heat exchanger which are sequentially connected in series; each heat exchanger is provided with a material inlet, a material outlet, a heat exchange inlet and a heat exchange outlet; methanol water is introduced into a material inlet of the first heat exchanger; and the adsorbed hydrogen outlet is communicated with a heat exchange inlet of the first heat exchanger. According to the technical scheme, the energy consumption of the methanol reforming hydrogen production device can be greatly reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of methanol hydrogen production, in particular to a heat recovery system of a methanol hydrogen production device. Background Art

[0002] Currently, 5,000 kg / d methanol reforming hydrogen production units all utilize a low-temperature catalyst coupled with a pressure swing adsorption purification process. The primary research direction for process innovation within these units is focused on combining rapid pressure swing adsorption with palladium membrane purification technology to optimize the methanol reforming process flow and footprint, while also increasing hydrogen yield and purity.

[0003] However, since the catalysts used in palladium membrane purification technology are all high-temperature catalysts, pressure swing adsorption purification needs to be carried out at a lower temperature, and the reforming hydrogen production reaction also needs to be carried out at 400-500°C, this combined purification technology solution will cause waste of heat energy. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the present invention provides the following technical solutions:

[0005] Provided is a heat recovery system for a methanol-to-hydrogen device, comprising a reforming reactor, a pressure swing adsorber, a purifier, and a heat exchanger; the reforming reactor, pressure swing adsorber, and purifier are connected in series in sequence; the reforming reactor is provided with a methanol-water inlet; the pressure swing adsorber is provided with an adsorber inlet, an adsorbed hydrogen outlet, and a desorption gas outlet; the heat exchanger is provided before the methanol-water inlet of the reforming reactor; the heat exchanger comprises a first heat exchanger, a second heat exchanger, and a third heat exchanger connected in series in sequence; the heat exchangers are all provided with a material inlet, a material outlet, a heat exchange inlet, and a heat exchange outlet; and the material inlet of the first heat exchanger is fed with methanol-water.

[0006] Preferably, the heat exchanger includes a fourth heat exchanger; the reforming reactor also includes a reformed mixed gas outlet, and the purifier includes a purifier inlet, a purified hydrogen outlet, and a purified tail gas outlet; the material inlet of the fourth heat exchanger is connected to the reformed mixed gas outlet, and the material outlet of the fourth heat exchanger is connected to the adsorber inlet; the desorption gas outlet is connected to the heat exchange inlet of the fourth heat exchanger, and the heat exchange outlet of the fourth heat exchanger is connected to the purifier inlet; the purified hydrogen outlet is connected to the heat exchange inlet of the second heat exchanger.

[0007] Preferably, the heat recovery system also includes a catalytic oxidizer, which is provided with an oxidizer inlet and a combustion gas outlet; the reformer reactor includes a reformer heat exchange inlet and a reformer heat exchange outlet; the oxidizer inlet is connected to the purified tail gas outlet; the combustion gas outlet is connected to the reformer heat exchange inlet; the reformer heat exchange outlet is connected to the heat exchange inlet of the third heat exchanger.

[0008] Preferably, the heat exchanger further includes a fifth heat exchanger; air is introduced into the material inlet of the fifth heat exchanger, and the material outlet of the fifth heat exchanger is connected to the oxidizer inlet; the heat exchange inlet of the fifth heat exchanger is connected to the heat exchange outlet of the third heat exchanger.

[0009] Preferably, the heat recovery system further includes a circulation compressor, which is provided with a gas inlet and a gas outlet; the gas inlet is provided at the heat exchange outlet of the fifth heat exchanger; and the gas outlet is provided at the material inlet of the fifth heat exchanger.

[0010] Preferably, the heat recovery system further comprises a heater, which is provided between the heat exchange outlet of the fourth heat exchanger and the inlet of the purifier.

[0011] Preferably, the heat recovery system further comprises a water separator, which is provided between the adsorbed hydrogen outlet of the pressure swing adsorber and the heat exchange inlet of the first heat exchanger.

[0012] Preferably, the heat recovery system further includes a water cooler, which is arranged at the heat exchange outlet of the second heat exchanger.

[0013] Preferably, the heat recovery system is further provided with a methanation device, and the methanation device is provided between the purified hydrogen outlet and the heat exchange inlet of the second heat exchanger.

[0014] Preferably, the adsorbed hydrogen outlet is communicated with the heat exchange inlet of the first heat exchanger.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] Under the conditions of adopting rapid pressure swing adsorption-palladium membrane combined purification technology, by setting up multiple heat exchangers in the entire process flow, the various fluids in the hydrogen production process undergo multiple heat exchanges, which greatly improves the thermal utilization rate of the hydrogen production device; the heat in the system is efficiently utilized, and the energy consumption of the methanol reforming hydrogen production device is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of the heat recovery system in Examples 1 and 2 of the present application;

[0018] Figure 2This is a schematic structural diagram of the heat recovery system in Example 3 of the present application. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] Example 1:

[0021] like Figure 1 As shown, a heat recovery system of a methanol hydrogen production device includes a reforming reactor 1, a pressure swing adsorber 2, a purifier 3 and a heat exchanger 4; the reforming reactor 1 is used to catalyze a methanol-water reaction to obtain a reformed mixed gas containing hydrogen; the pressure swing adsorber 2 is used to perform a first purification of the reformed mixed gas; the purifier 3 is used to further purify the desorption gas generated by the pressure swing adsorber; the heat exchanger is used to recover the residual heat energy in the methanol hydrogen production process and recycle it for use in the methanol hydrogen production process.

[0022] Specifically, the heat exchanger is located before the methanol-water inlet of the reforming reactor 1. The heat exchanger comprises a first heat exchanger 4, a second heat exchanger 5, and a third heat exchanger 6, connected in series. Each heat exchanger is equipped with a material inlet, a material outlet, a heat exchange inlet, and a heat exchange outlet. The first heat exchanger 4 is used to preheat the methanol-water, the second heat exchanger 5 is used to reheat the preheated methanol-water, and the third heat exchanger 6 is used to vaporize the reheated methanol-water to reach the reforming reaction temperature. The reforming reactor 1 is equipped with a methanol-water inlet 11, a reformed mixed gas outlet 12, a reformer heat exchange inlet 13, and a reformer heat exchange outlet 14. The pressure swing adsorber 2 is equipped with an adsorber inlet 21, an adsorbed hydrogen outlet 22, and a desorbed gas outlet 23. The purifier 3 is equipped with a purifier inlet 31, a purified hydrogen outlet 32, and a purified tail gas outlet 33. The first heat exchanger 4 , the second heat exchanger 5 and the third heat exchanger 6 are arranged between the methanol water storage tank (not shown in the figure) and the reforming reactor 1 .

[0023] The material inlet of the first heat exchanger 4 is connected to the methanol water tank, the material outlet of the first heat exchanger 4 is connected to the material inlet of the second heat exchanger 5, and the material outlet of the second heat exchanger 5 is connected to the material inlet of the third heat exchanger 6; the material outlet of the third heat exchanger 6 is connected to the methanol water inlet 11 of the reforming reactor 1, the reformed mixed gas outlet 12 of the reforming reactor 1 is connected to the adsorber inlet 21 of the pressure swing adsorber 2, the decomposed gas outlet 33 is connected to the purifier inlet 31, and the hydrogen obtained by the first purification by the pressure swing adsorber 2 flows out from the adsorbed hydrogen outlet 22 of the pressure swing adsorber 2.

[0024] To fully utilize the thermal energy in the methanol-to-hydrogen device, the adsorbed hydrogen outlet 22 of the pressure swing adsorber 2 is connected to the heat exchange inlet of the first heat exchanger 4, and flows out through the heat exchange outlet of the first heat exchanger 4. The purified hydrogen outlet 32 ​​of the purifier 3 is connected to the heat exchange inlet of the second heat exchanger 5, and flows out through the heat exchange outlet of the second heat exchanger 5. In addition, to store hydrogen, the heat exchange outlets of the first heat exchanger 4 and the second heat exchanger 5 are both connected to the hydrogen buffer tank 18.

[0025] During operation, after the methanol-water mixture flows out from the methanol-water tank, it flows into the first heat exchanger 4 through the material inlet of the first heat exchanger 4. In the first heat exchanger 4, the methanol-water exchanges heat with the hydrogen flowing out from the adsorbed hydrogen outlet 22, thereby preheating the methanol-water; the preheated methanol-water flows out from the material outlet of the first heat exchanger 4, flows into the second heat exchanger 5 through the material inlet of the second heat exchanger 5, and exchanges heat with the high-temperature hydrogen flowing out from the purified hydrogen outlet 32 ​​in the second heat exchanger 5, thereby heating the preheated methanol-water; the heated methanol-water flows out from the material outlet of the second heat exchanger 5, flows into the third heat exchanger 6 through the material inlet of the third heat exchanger 6, and the heated methanol-water in the third heat exchanger 6 is heated again and vaporized to obtain methanol-water vapor, which then flows out from the material outlet of the third heat exchanger 6 and passes through the methanol inlet of the reforming reactor 1. The alcohol-water inlet 11 flows into the reforming reactor 1, where a reforming reaction is carried out to obtain a reformed mixed gas. After being cooled, the reformed mixed gas flows into the pressure swing adsorber 2 from the adsorber inlet 21, where the first hydrogen purification is carried out in the pressure swing adsorber 2. The purified hydrogen flows out from the adsorbed hydrogen outlet 22, then flows through the heat exchange inlet of the first heat exchanger 4, passes through the first heat exchanger 4, and then flows into the hydrogen buffer tank 18 after heat exchange; the remaining decomposed gas after purification flows out from the decomposed gas outlet 23, and flows into the purifier 3 through the purifier inlet 31 for a second hydrogen purification; the hydrogen after the second purification flows out from the purified hydrogen outlet 32 ​​of the purifier 3, flows through the heat exchange inlet of the second heat exchanger 5, passes through the second heat exchanger 5, and then flows into the hydrogen buffer tank 18 for buffering; the remaining purified tail gas after the second purification flows out of the purifier through the purified tail gas outlet.

[0026] Example 2:

[0027] Since the reforming reaction requires a very high temperature, the reformed mixed gas obtained by the reforming reaction also carries a lot of heat energy. At the same time, the pressure swing adsorber 2 needs to be at about 40°C to achieve a higher purification efficiency. Moreover, the purified tail gas remaining after purification by the purifier 3 also contains combustible heat-releasing gases such as hydrogen, carbon monoxide, and methane. Therefore, in order to improve the system thermal efficiency of the methanol hydrogen production device, the difference between this embodiment and embodiment 1 is that, Figure 2 As shown, the heat exchanger also includes a fourth heat exchanger, and the heat recovery system is further provided with a catalytic oxidizer 8; the fourth heat exchanger is provided with a material inlet, a material outlet and a heat exchange inlet, a heat exchange outlet; the catalytic oxidizer 8 is provided with an oxidizer inlet 81 and a combustion gas outlet 82.

[0028] The material inlet of the fourth heat exchanger is connected to the reformed mixed gas outlet 12, and the material outlet of the fourth heat exchanger is connected to the adsorber inlet 31; the heat exchange inlet of the fourth heat exchanger is connected to the desorbed gas outlet 23. By exchanging heat between the reformed mixed gas and the desorbed gas, the temperature of the reformed mixed gas can be lowered, enabling more efficient purification by the pressure swing adsorber. Furthermore, since the purification reaction in the purifier requires high heat, the low-temperature desorbed gas is passed through the fourth heat exchanger for heat exchange with the high-temperature reformed mixed gas. This not only lowers the temperature of the reformed mixed gas but also increases the temperature of the desorbed gas, thereby more effectively utilizing the system's thermal energy.

[0029] Furthermore, in order to ensure that the heating temperature of the desorbed gas meets the requirements of the second purification, the system is also provided with a heater 7, which has a heater inlet and a heater outlet, wherein the heater inlet is connected to the heat exchange outlet of the fourth heat exchanger, and the heater outlet is connected to the purifier inlet 31.

[0030] The purified tail gas outlet 33 is connected to the oxidizer inlet of the catalytic oxidizer 8, the combustion gas outlet of the catalytic oxidizer 8 is connected to the reforming reactor heat exchange inlet 13, and the reformer heat exchange outlet 14 is connected to the heat exchange inlet of the third heat exchanger 6. After heat exchange in the third heat exchanger 6, the cooled combustion gas flows out of the heat exchange outlet of the third heat exchanger 6.

[0031] During operation, the reformed mixed gas flows out of the reforming reactor 1 from the reformed mixed gas outlet, flows to the adsorber inlet 21 through the material inlet of the fourth heat exchanger, and undergoes the first hydrogen purification in the pressure swing adsorber 2. The remaining desorption gas flows out from the desorption gas outlet 23 and flows into the fourth heat exchanger through the heat exchange inlet of the fourth heat exchanger. After the desorption gas and the reformed mixed gas undergo heat exchange in the fourth heat exchanger, the heated desorption gas flows out from the heat exchange outlet of the fourth heat exchanger and flows into the heater through the heater inlet so that the desorption gas temperature reaches the reaction temperature required by the purifier. After the desorption gas undergoes secondary purification in the purification reactor, the remaining purified tail gas It flows to the oxidizer inlet through the purified tail gas outlet 33; in order to fully burn the remaining purified tail gas, mixed air is introduced into the oxidizer inlet at the same time, and the purified tail gas fully burned in the catalytic oxidizer 8 is converted into combustion gas carrying a large amount of heat. The combustion gas flows into the reforming reactor 1 through the heat inlet of the reforming reactor to provide heat energy for the reforming reaction, and then flows out from the heat outlet 14 of the reforming reactor, and flows into the third heat exchanger 6 through the heat inlet of the third heat exchanger 6, so that the combustion gas after heat exchange continues to exchange heat with methanol water, and finally vaporizes the methanol water; the cooled combustion gas after heat exchange flows out through the heat exchange outlet of the third heat exchanger.

[0032] Example 3:

[0033] Since the cooling combustion gas flowing out of the reforming reactor outlet still has a high temperature of 300-500°C, even after heat exchange in the third heat exchanger 6, the cooling combustion gas still has a relatively high temperature. In order to fully utilize this part of the heat energy, the difference between this embodiment and embodiment 1 or 2 is that, Figure 2 As shown, the heat recovery system is further provided with a fifth heat exchanger 9, and the fifth heat exchanger 9 is also provided with a material inlet, a material outlet, a heat exchange inlet, and a heat exchange outlet.

[0034] The heat exchange inlet of the fifth heat exchanger 9 is connected to the heat exchange outlet of the third heat exchanger, and the material outlet of the fifth heat exchanger is connected to the catalytic oxidizer inlet 81; the material inlet of the fifth heat exchanger 9 is passed into air, and the heat exchange outlet of the fifth heat exchanger flows out the re-cooled combustion gas mainly composed of carbon dioxide.

[0035] In addition, the heat recovery system is further provided with an air compressor 15 and a carbon dioxide capture device 16 . The air compressor 15 is connected to the material inlet of the fifth heat exchanger 9 ; the carbon dioxide capture device 16 is connected to the heat exchange outlet of the fifth heat exchanger 9 .

[0036] Furthermore, the heat recovery system is further provided with a circulation compressor 17. The circulation compressor 17 is provided with a gas inlet and a gas outlet. The gas inlet of the circulation compressor 17 is provided at the heat exchange outlet of the fifth heat exchanger 9, specifically, between the heat exchange outlet of the fifth heat exchanger 9 and the carbon dioxide capture device 16. The gas outlet of the circulation compressor 17 is provided at the material inlet of the fifth heat exchanger 9, specifically, between the material inlet of the fifth heat exchanger 9 and the air compressor 15.

[0037] During operation, part of the re-cooled combustion gas flows into the carbon dioxide capture device 16, and part of it is mixed with air through the circulation compressor 17 to form mixed air. The mixed air flows into the fifth heat exchanger 9 through the material inlet of the fifth heat exchanger 9, and after the mixed air and the cooled combustion gas are heat exchanged in the fifth heat exchanger 9, it flows into the catalytic oxidizer through the heat exchange outlet of the fifth heat exchanger 9, so that part of the heat continues to return to the heat recovery system to be utilized.

[0038] The heat recovery system also includes a water separator 19, a water cooler 20, and a methanation unit 24. The water separator 19 is located between the adsorbed hydrogen outlet 22 and the heat exchange inlet of the first heat exchanger 4. The water cooler 20 is located between the heat exchange outlet of the second heat exchanger 5 and the hydrogen buffer tank 18 to further cool the purified hydrogen. The methanation unit 24 is located between the purified hydrogen outlet 32 ​​of the purifier and the heat exchange inlet of the second heat exchanger 5.

[0039] It should be noted that the technical features in the above-mentioned embodiments 1 to 3 can be combined in any way, and the technical solutions formed by the combination all fall within the scope of protection of this application. In this article, terms such as "including", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements that are not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "including a..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0040] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A heat recovery system for a methanol-to-hydrogen device, comprising a reforming reactor, a pressure swing adsorber, a purifier, and a heat exchanger; the reforming reactor, the pressure swing adsorber, and the purifier are sequentially connected in series; the reforming reactor is provided with a methanol-water inlet; the pressure swing adsorber is provided with an adsorber inlet, an adsorbed hydrogen outlet, and a desorption gas outlet; characterized in that: The heat exchanger is arranged in front of the methanol water inlet of the reforming reactor; the heat exchanger includes a first heat exchanger, a second heat exchanger and a third heat exchanger connected in series in sequence; the heat exchangers are all provided with a material inlet, a material outlet and a heat exchange inlet and a heat exchange outlet; the material inlet of the first heat exchanger is introduced into methanol water.

2. The heat recovery system according to claim 1, wherein: The heat exchanger includes a fourth heat exchanger; the reforming reactor also includes a reformed mixed gas outlet, and the purifier includes a purifier inlet, a purified hydrogen outlet, and a purified tail gas outlet; the material inlet of the fourth heat exchanger is connected to the reformed mixed gas outlet, and the material outlet of the fourth heat exchanger is connected to the adsorber inlet; the desorption gas outlet is connected to the heat exchange inlet of the fourth heat exchanger, and the heat exchange outlet of the fourth heat exchanger is connected to the purifier inlet; the purified hydrogen outlet is connected to the heat exchange inlet of the second heat exchanger.

3. The heat recovery system according to claim 2, characterized in that The heat recovery system also includes a catalytic oxidizer, which is provided with an oxidizer inlet and a combustion gas outlet; the reformer reactor includes a reformer heat exchange inlet and a reformer heat exchange outlet; the oxidizer inlet is connected to the purified tail gas outlet; the combustion gas outlet is connected to the reformer heat exchange inlet; the reformer heat exchange outlet is connected to the heat exchange inlet of the third heat exchanger.

4. The heat recovery system according to claim 3, wherein: The heat exchanger also includes a fifth heat exchanger; air is introduced into the material inlet of the fifth heat exchanger, and the material outlet of the fifth heat exchanger is connected to the oxidizer inlet; the heat exchange inlet of the fifth heat exchanger is connected to the heat exchange outlet of the third heat exchanger.

5. The heat recovery system according to claim 4, characterized in that The heat recovery system further includes a circulation compressor, which is provided with a gas inlet and a gas outlet; the gas inlet is provided at the heat exchange outlet of the fifth heat exchanger; and the gas outlet is provided at the material inlet of the fifth heat exchanger.

6. The heat recovery system according to any one of claims 1 to 5, characterized in that: The heat recovery system further includes a heater, which is provided between the heat exchange outlet of the fourth heat exchanger and the inlet of the purifier.

7. The heat recovery system according to claim 6, characterized in that The heat recovery system further includes a water separator, which is provided between the adsorbed hydrogen outlet of the pressure swing adsorber and the heat exchange inlet of the first heat exchanger.

8. The heat recovery system according to claim 6, wherein: The heat recovery system further includes a water cooler, which is arranged at the heat exchange outlet of the second heat exchanger.

9. The heat recovery system according to claim 6, wherein: The heat recovery system is further provided with a methanation device, which is arranged between the purified hydrogen outlet and the heat exchange inlet of the second heat exchanger.

10. The heat recovery system according to claim 1, wherein: The adsorbed hydrogen outlet is communicated with the heat exchange inlet of the first heat exchanger.

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