Resource utilization system for desorbed gas byproduct of methanol hydrogen production

Abstract

A resource utilization system for a desorbed gas byproduct of methanol hydrogen production, comprising: a methanol steam reforming unit, comprising a reforming reactor and a PSA hydrogen extraction apparatus, the PSA hydrogen extraction apparatus being in communication with a desorbed gas byproduct outlet pipe; and a regenerative thermal oxidation unit, comprising a tail gas oxidation furnace and a thermally conductive oil heat supply loop, the tail gas oxidation furnace being in communication with the desorbed gas byproduct outlet pipe, the thermally conductive oil heat supply loop being in communication with a cold side pipeline of a countercurrent heat exchanger and the reforming reactor in sequence, a hot side pipeline of the countercurrent heat exchanger being connected in series to an exhaust pipe of the tail gas oxidation furnace, and a cold side outlet of the countercurrent heat exchanger being in communication with the reforming reactor, to supply heat to the reforming reactor until a temperature required for a reforming reaction is reached. The present application uses a tail gas oxidation furnace and, by means of thermal oxidation using methane as fuel, oxidizes and decomposes a combustible desorbed gas byproduct. The flue gas of the tail gas oxidation furnace and the circulating thermally conductive oil undergo convective heat transfer, to heat the thermally conductive oil to a specified temperature required by the reforming reactor, so as to provide heat for the reaction, thereby improving the safety and reliability of the device, and reducing environmental pollution and energy waste.

Description

A resource utilization system for desorbed gas produced as a by-product of methanol-to-hydrogen production Technical Field

[0001] The utility model belongs to the technical field of methanol hydrogen production, and relates to a resource utilization system of desorbed gas, a by-product of methanol hydrogen production. Background Art

[0002] Methanol-to-hydrogen production involves the catalytic action of methanol and water vapor at a certain temperature and pressure to produce hydrogen and carbon dioxide through a methanol cracking reaction and a carbon monoxide shift reaction. It is a multi-component, multi-reaction gas-solid catalytic reaction system. The reactions are as follows:

[0003] CH3OH→CO+2H2-90.8KJ / mol

[0004] CO + H2O → CO2 + H2 + 43.5 kJ / mol

[0005] The cracking reaction is a highly endothermic reaction, while the shift reaction is exothermic. The entire reaction process within the reactor is endothermic, requiring heating for the vaporizer and methanol decomposition reactor. The heat required for the reaction is typically supplied by a thermal oil system, which uses circulating thermal oil to heat the reactor, typically at around 250°C. However, this thermal oil system requires equipment such as a high-temperature oil pump, expansion tank, and thermal oil furnace. This system is complex, difficult to integrate, and expensive. Furthermore, it is an open-flame device. Refer to Table 5.2.1 of GB50160-2018 for spacing requirements between open-flame equipment and the reaction unit, resulting in a large footprint and investment.

[0006] In addition, in the methanol-to-hydrogen process, the hydrogen obtained is mixed with a variety of impurity gases. The process usually uses pressure swing adsorption technology to purify the hydrogen. Currently, while the PSA unit purifies the hydrogen, the by-product desorption gas (containing carbon dioxide, hydrogen, a small amount of methanol and carbon monoxide) will be directly released into the atmosphere, causing environmental pollution and waste of resources. Technical Solutions

[0007] In response to the problems of by-product desorption gas from the PSA hydrogen extraction unit of a methanol hydrogen production device being discharged into the atmosphere and the complex and large thermal oil furnace system, the purpose of the utility model is to provide a resource utilization system for the by-product desorption gas from methanol hydrogen production. The system adopts a tail gas oxidation furnace and uses methanol as fuel through thermal oxidation to oxidize and decompose the combustible by-product desorption gas. The flue gas from the tail gas oxidation furnace and the circulating thermal oil transfer heat by convection, and the thermal oil is heated to the specified temperature required by the reforming reactor to provide heat for the reaction, thereby improving the safety and reliability of the device and reducing environmental pollution and energy waste.

[0008] In order to achieve the above purpose, the technical solutions adopted by this utility model are as follows:

[0009] A resource utilization system for desorbed gas produced as a by-product of methanol-to-hydrogen production, comprising:

[0010] A methanol steam reforming unit comprising a reforming reactor and a PSA hydrogen extraction device, wherein the PSA hydrogen extraction device is connected to a by-product desorption gas outlet pipe;

[0011] The regenerative oxidation unit includes a tail gas oxidation furnace and a thermal oil heat supply circuit. The tail gas oxidation furnace is connected to the by-product desorption gas outlet pipe. The thermal oil heat supply circuit is connected in sequence to the cold side pipeline of the countercurrent heat exchanger and the reforming reactor. The hot side pipeline of the countercurrent heat exchanger is connected in series to the flue gas exhaust pipeline of the tail gas oxidation furnace. The cold side outlet of the countercurrent heat exchanger is connected to the reforming reactor for supplying heat to the reforming reactor to the temperature required for the reforming reaction.

[0012] In some technical solutions, the exhaust pipe of the tail gas oxidation furnace is connected to the hot side pipe of the air preheater, the cold side inlet of the air preheater is connected to the air source, and the cold side outlet is connected to the tail gas oxidation furnace.

[0013] In some technical solutions, the exhaust pipe outlet of the tail gas oxidation furnace is divided into two routes, one of which is connected back to the tail gas oxidation furnace to form a combustion air branch, and a hot air circulation blower is arranged on the combustion air branch; the other route is connected to the chimney.

[0014] In some technical solutions, the thermal oil heat supply circuit is connected to a raw material vaporizer, the hot side of the raw material vaporizer is connected to the connecting pipeline between the thermal oil outlet of the reforming reactor and the cold side inlet of the countercurrent heat exchanger, the reforming reactor is connected to a raw material inlet pipe, and the cold side of the raw material vaporizer is connected to the raw material inlet pipe.

[0015] In some technical solutions, an oil-gas separator is provided on the pipeline between the hot side outlet of the raw material vaporizer and the cold side inlet of the countercurrent heat exchanger.

[0016] In some technical solutions, the methanol steam reforming unit also includes a raw material preheater, the reforming reactor is connected to a reaction gas outlet pipe, the hot side of the raw material preheater is connected to the reaction gas outlet pipe, and the raw material inlet pipe is sequentially connected to the cold side of the raw material preheater and the cold side of the raw material vaporizer.

[0017] In some technical solutions, the methanol steam reforming unit also includes a separator connected in series to the pipeline between the reforming reactor and the PSA hydrogen extraction device, and the liquid phase outlet of the separator is backconnected to the raw material buffer tank, which is arranged on the feed pipeline of the reforming reactor.

[0018] In some technical solutions, the methanol steam reforming unit further includes a cooler connected in series to the pipeline between the reforming reactor and the separator.

[0019] In some technical solutions, the reforming reactor is connected to a raw material inlet pipe, a raw material buffer tank is provided on the raw material inlet pipe, a liquid supply branch is provided at the inlet end of the raw material buffer tank, one end of the liquid supply branch is connected to the methanol inlet, and the other end is connected to the exhaust gas oxidation furnace.

[0020] In some technical solutions, the resource utilization system for the desorption gas produced as a by-product of methanol-to-hydrogen production is a skid-mounted equipment. Beneficial effects

[0021] The above technical solution adopted by the present invention has at least the following beneficial effects:

[0022] 1. The resource utilization system for methanol-to-hydrogen by-product desorption gas proposed in this utility model solves the problem of by-product desorption gas emissions by adding a tail gas oxidation furnace, thereby reducing environmental pollution, safety hazards and energy waste;

[0023] 2. The resource utilization system for methanol-to-hydrogen byproduct desorption gas proposed in this utility model uses the flue gas from the tail gas oxidation furnace as the heat source, convection heating the circulating thermal oil. Because the tail gas oxidation furnace is not treated as an open flame device, it is not required to comply with Table 5.2.1 of GB50160-2018, thus effectively reducing the floor space required.

[0024] 3. The utility model proposes a resource utilization system for the desorbed gas produced as a byproduct of methanol-to-hydrogen production. The heat transfer oil obtained through heat exchange with the flue gas from the tail gas oxidation furnace is used to provide the heat required by the reforming reactor and the raw material vaporizer.

[0025] 4. In the resource utilization system for methanol-to-hydrogen byproduct desorption gas proposed in this utility model, the flue gas discharged from the exhaust oxidation furnace can also preheat the air entering the exhaust oxidation furnace. At the same time, a portion of the flue gas can be circulated to the exhaust oxidation furnace as combustion-supporting air through the hot air circulation blower.

[0026] 5. The resource utilization system for the desorbed gas produced as a by-product of methanol-to-hydrogen production proposed in this utility model adopts skid-mounted equipment, which has a compact structure, saves space, greatly reduces the floor space, and is easy to dismantle and save costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following is a brief introduction to the drawings and their markings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] FIG1 is a schematic structural diagram of a system for resource utilization of desorbed gas produced as a by-product of methanol-to-hydrogen production according to an embodiment of the present invention.

[0029] The meanings of the symbols in the figure are as follows:

[0030] 11 - raw material buffer tank, 12 - raw material pump, 13 - raw material preheater, 14 - raw material vaporizer, 15 - reforming reactor, 16 - cooler, 17 - separator, 18 - PSA hydrogen extraction device;

[0031] 21—Tail gas oxidation furnace, 22—Convection heat exchanger, 23—Air preheater, 24—Air blower, 25—Hot air circulation blower, 26—Chimney, 27—Oil-gas separator. Modes for Carrying Out the Invention

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without inventive work.

[0033] To simplify the drawings, only the parts relevant to the utility model are schematically shown in each figure; they do not represent the actual structure of the product. Furthermore, to simplify the drawings and facilitate understanding, in some figures, only one of the components with the same structure or function is schematically depicted or labeled. In this document, "one" not only means "only one" but also "more than one."

[0034] It should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they can refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on the specific circumstances.

[0035] According to a specific embodiment of the present invention, please refer to Figure 1, which shows a resource utilization system for by-product desorption gas from methanol hydrogen production, including a methanol steam reforming unit and a regenerative oxidation unit, the methanol steam reforming unit including a reforming reactor 15 and a PSA hydrogen extraction device 18, wherein the PSA hydrogen extraction device 18 is connected to a by-product desorption gas outlet pipe; the regenerative oxidation unit includes a tail gas oxidation furnace 21 and a thermal oil heat supply circuit, the tail gas oxidation furnace 21 is connected to the by-product desorption gas outlet pipe, the thermal oil heat supply circuit is connected in sequence to the cold side pipeline of the countercurrent heat exchanger 22 and the reforming reactor 15, the hot side pipeline of the countercurrent heat exchanger 22 is connected in series to the exhaust pipe of the tail gas oxidation furnace 21, and the cold side outlet of the countercurrent heat exchanger 22 is connected to the reforming reactor 15, for supplying heat to the reforming reactor 15 to the temperature required for the reforming reaction.

[0036] In this embodiment, the by-product desorbed gas produced by the methanol steam reforming unit is not directly discharged into the atmosphere to pollute the environment. Instead, the by-product desorbed gas is introduced into the tail gas oxidation furnace 21 for full combustion, and the flue gas formed by the combustion is subjected to convection heat exchange with the thermal oil to recover the oxidation heat. This avoids the use of open flame equipment, effectively reducing investment and floor space. The thermal oil heat exchanged by the flue gas is used to supply heat to the reforming reactor 15 to the temperature required for the reforming reaction. The by-product desorbed gas resource utilization system of the present application is novel in design. By oxidizing and burning the by-product desorbed gas and recycling the heat energy, it fully utilizes the surplus energy, solves the layout limitations of the thermal oil, and significantly reduces the production cost of the methanol hydrogen production process.

[0037] In the above embodiment, the reforming reactor 15 is connected to a raw material inlet pipe and a reaction gas outlet pipe. The raw material inlet pipe connects the raw material pump 12 and the raw material buffer tank 11. The inlet end of the raw material buffer tank 11 is provided with two parallel streams, one connected to the methanol inlet and the other connected to the desalted water inlet; the reaction gas outlet pipe is connected to the hot side of the raw material preheater 13, and the cold side of the raw material preheater 13 is connected to the raw material inlet pipe.

[0038] Furthermore, the raw material inlet pipe is connected in sequence to the cold side of the raw material preheater 13 and the cold side of the raw material vaporizer 14, and the hot side of the raw material vaporizer 14 is connected to the connecting pipeline between the heat transfer oil outlet of the reforming reactor 15 and the cold side inlet of the countercurrent heat exchanger 22.

[0039] In this embodiment, the raw materials are first preheated by the reaction gas produced by the reforming reactor 15, and then the raw materials are vaporized by heat exchange with the thermal oil. On the one hand, the residual energy of the reaction gas can be recovered, and on the other hand, the time for vaporizing the raw materials with the thermal oil can be shortened, thereby improving the vaporization efficiency, allowing the methanol steam reforming reaction to proceed continuously, and further improving the reforming reaction conversion efficiency.

[0040] In the above embodiment, the methanol steam reforming unit also includes a cooler 16 and a separator 17 connected in series to the pipeline between the reforming reactor 15 and the PSA hydrogen extraction device 18, wherein the cooler 16 is used to cool the reaction gas to 40°C by heat exchange with circulating water, and the cooled reaction gas enters the separator 17, the liquid phase outlet of the separator 17 is backconnected to the raw material buffer tank 11, and the gas phase outlet enters the PSA hydrogen extraction device 18.

[0041] In this embodiment, the reaction gas is cooled and separated in sequence, and the unreacted liquid is returned to the raw material buffer tank 11 to be mixed with the raw material and enter the subsequent methanol steam reforming hydrogen production process, thereby saving raw material resources.

[0042] The outlet of the above-mentioned PSA hydrogen extraction device 18 is divided into two routes, one route outputs product gas, and the other route guides by-product desorption gas to the tail gas combustion furnace. A liquid supply branch is set at the inlet end of the raw material buffer tank 11, one end of the liquid supply branch is connected to the methanol inlet, and the other end is connected to the tail gas oxidation furnace 21, supplying fuel methanol to the tail gas oxidation furnace 21; the exhaust pipe of the tail gas oxidation furnace 21 is connected to the hot side pipe of the air preheater 23, the cold side inlet of the air preheater 23 is connected to the air blower 24, and the cold side outlet is connected to the tail gas oxidation furnace 21.

[0043] In this embodiment, the waste heat of the flue gas is further used to preheat the air, so that the waste energy of the flue gas can be completely recycled.

[0044] In one specific embodiment, the exhaust pipe outlet of the exhaust gas oxidation furnace 21 is divided into two paths. One path is connected back to the exhaust gas oxidation furnace 21 to form a combustion air branch, which is equipped with a hot air circulation blower 25; the other path is connected to a chimney 26 for external exhaust. In this case, the exhaust gas, after being fully oxidized, avoids environmental pollution and is more environmentally friendly.

[0045] In the above embodiment, an oil-gas separator 27 is further provided on the heat transfer oil heat supply circuit. The oil-gas separator 27 is preferably provided between the hot side outlet of the raw material vaporizer 14 and the cold side inlet of the countercurrent heat exchanger 22 .

[0046] Preferably, the present application adopts skid-mounted equipment, which has a compact structure, saves space, greatly reduces the floor space, is easy to dismantle, and saves costs.

[0047] This application adopts a tail gas oxidation furnace 21, which uses methanol as fuel through thermal oxidation to oxidize and decompose the combustible by-product desorption gas. The flue gas of the tail gas oxidation furnace 21 and the circulating heat transfer oil are convectively heat-transferred to heat the heat transfer oil to the specified temperature required by the reforming reactor 15 to provide heat for the reaction, thereby improving the safety and reliability of the device and reducing environmental pollution and energy waste.

[0048] The oxidized flue gas is further exchanged with air to fully utilize the waste heat, and the raw materials are vaporized with heat transfer oil to further utilize the waste energy. The process is smooth, the operation is simple, the equipment is compact, the cost is saved, and the hydrogen production efficiency is significantly improved.

[0049] In order to have a clear understanding of the technical solution and technical effects of this application, the process flow of the resource utilization system of the desorbed gas produced as a by-product of methanol-to-hydrogen production is now described in detail:

[0050] Methanol raw material and desalted water are mixed in a certain proportion in the raw material buffer tank 11, and then pressurized by the raw material pump 12 and sent to the raw material preheater 13 for heat exchange with the reaction gas to increase the temperature. The heated methanol-water solution then enters the raw material vaporizer 14, and is heated and vaporized to the reaction temperature by high-temperature circulating heat transfer oil. The vaporized methanol and water vapor enter the reforming reactor 15, and undergo cracking and shift reactions under the action of the catalyst. The cracking reaction is a strongly endothermic reaction, and the shift reaction is an exothermic reaction. The entire reaction process in the reforming reactor 15 is endothermic, and the heat required for the reforming reactor 15 and the raw material vaporizer is provided by the circulating heat transfer oil.

[0051] After heat exchange with the reaction feed, the reaction gas from reforming reactor 15 enters cooler 16 and is cooled to 40°C. It is then separated in separator 17 and fed to PSA hydrogen extraction unit 18. The unreacted liquid in separator 17 is returned to the feed buffer tank and mixed with the feed. The reaction gas is purified by PSA hydrogen extraction unit 18, and the product hydrogen exits the unit. The by-product desorbed gas enters the tail gas oxidation furnace 21.

[0052] The circulating heat transfer oil is separated by the oil-gas separator 27, pressurized by the heat transfer oil circulation pump, and enters the convection heat exchanger 22 for convection heat transfer with the flue gas, heating the heat transfer oil to the specified temperature required by the reforming reactor 15 to provide heat for the reaction.

[0053] The tail gas oxidation furnace 21 burns methanol as fuel to oxidize and decompose the combustible desorbed gas produced as a by-product of the PSA hydrogen extraction device 18. The generated flue gas exchanges heat with the heat transfer oil circulating in the system and enters the air preheater 23 to exchange heat with the air entering the tail gas oxidation furnace 21. After that, a part of it is circulated to the tail gas oxidation furnace 21 as combustion-supporting air through the hot air circulation blower 25, and a part of it is discharged into the atmosphere through the chimney 26.

[0054] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the scope of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A system for resource utilization of by-product desorption gas from methanol hydrogen production, characterized in that: include: A methanol steam reforming unit, comprising a reforming reactor and a PSA hydrogen extraction device, wherein the PSA hydrogen extraction device is connected to a by-product desorption gas outlet pipe; The regenerative oxidation unit comprises a tail gas oxidation furnace and a heat transfer oil heat supply circuit, wherein the tail gas oxidation furnace is connected to the by-product desorption gas outlet pipe, the heat transfer oil heat supply circuit is connected in sequence to the cold side pipeline of the countercurrent heat exchanger and the reforming reactor, the hot side pipeline of the countercurrent heat exchanger is connected in series to the exhaust pipe of the tail gas oxidation furnace, and the cold side outlet of the countercurrent heat exchanger is connected to the reforming reactor for supplying heat to the reforming reactor to the temperature required for the reforming reaction.

2. The resource utilization system of methanol hydrogen production by-product desorption gas according to claim 1, characterized in that: The exhaust pipe of the tail gas oxidation furnace is connected to the hot side pipe of the air preheater, the cold side inlet of the air preheater is connected to the air source, and the cold side outlet is connected to the tail gas oxidation furnace.

3. The resource utilization system of methanol hydrogen production by-product desorption gas according to claim 1 or 2, characterized in that: The exhaust pipe outlet of the tail gas oxidation furnace is divided into two paths, one of which is connected back to the tail gas oxidation furnace to form a combustion air branch, and a hot air circulation blower is arranged on the combustion air branch; the other is connected to the chimney.

4. The resource utilization system of methanol hydrogen production by-product desorption gas according to claim 1, characterized in that: The heat transfer oil heat supply circuit is connected to a raw material vaporizer, the hot side of the raw material vaporizer is connected to a connecting pipeline between the heat transfer oil outlet of the reforming reactor and the cold side inlet of the countercurrent heat exchanger, the reforming reactor is connected to a raw material inlet pipe, and the cold side of the raw material vaporizer is connected to the raw material inlet pipe.

5. The resource utilization system of methanol hydrogen production by-product desorption gas according to claim 4, characterized in that: An oil-gas separator is arranged on the pipeline between the hot side outlet of the raw material vaporizer and the cold side inlet of the countercurrent heat exchanger.

6. The resource utilization system of methanol hydrogen production by-product desorption gas according to claim 4, characterized in that: The methanol steam reforming unit also includes a raw material preheater. The reforming reactor is connected to a reaction gas outlet pipe. The hot side of the raw material preheater is connected to the reaction gas outlet pipe. The raw material inlet pipe is sequentially connected to the cold side of the raw material preheater and the cold side of the raw material vaporizer.

7. The resource utilization system of methanol-to-hydrogen by-product desorption gas according to claim 1, characterized in that: The methanol steam reforming unit also includes a separator connected in series to the pipeline between the reforming reactor and the PSA hydrogen extraction device, and the liquid phase outlet of the separator is back-connected to the raw material buffer tank, which is arranged on the feed pipeline of the reforming reactor.

8. The resource utilization system of methanol hydrogen production by-product desorption gas according to claim 7, characterized in that: The methanol steam reforming unit further includes a cooler connected in series to the pipeline between the reforming reactor and the separator.

9. The resource utilization system of methanol-to-hydrogen by-product desorption gas according to claim 1, characterized in that: The reforming reactor is connected to a raw material inlet pipe, a raw material buffer tank is arranged on the raw material inlet pipe, a liquid supply branch is arranged at the inlet end of the raw material buffer tank, one end of the liquid supply branch is connected to the methanol inlet, and the other end is connected to the tail gas oxidation furnace.

10. The resource utilization system of methanol-to-hydrogen by-product desorption gas according to claim 1, characterized in that: The resource utilization system of the by-product desorption gas from methanol to hydrogen is a skid-mounted equipment.

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