Process for the production of hydrogen from methanol

Abstract

The present application relates to hydrogen production technology field, especially to a kind of methanol hydrogen production method, comprising the following steps: S10: methanol water is heated and vaporized to obtain methanol water vapor;S20: methanol reforming reaction obtains hydrogen mixture gas;S30: after cooling treatment to hydrogen mixture gas, through water washing tower absorption unreacted methanol water, then, adjust the relative humidity and temperature of hydrogen mixture gas;S40: hydrogen mixture gas is input into carbon dioxide absorption tower to remove carbon dioxide;S50: after removing carbon dioxide, product hydrogen is obtained and input hydrogen tank storage to supply user end.The above-mentioned methanol hydrogen production method, by methanol water vapor reforming hydrogen treatment, obtains hydrogen mixture gas.Again, hydrogen mixture gas is purified to obtain product hydrogen with very low carbon monoxide content, with raw material easy to transport, the hydrogen purity of output is high, equipment construction cost is low, and energy consumption is low and the like advantages, reach the purpose of expanding hydrogen application range.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production technology, and in particular to a method for producing hydrogen from methanol. Background Technology

[0002] Hydrogen is a versatile gas. For example, its flammability allows it to react with oxygen, releasing a large amount of heat; the oxyhydrogen flame can reach temperatures of 3000°C, which can be used for welding or cutting metals. Its reducing properties also allow for the smelting of important metals. Hydrogen can be used to inflate balloons or airships, as a heat-conducting material in dual-hydrogen internally cooled generators, in the smelting of non-ferrous metals and high-purity germanium and silicon, in the synthesis of ammonia and hydrochloric acid, in petroleum hydrotreating, in the production of hardened oils, and as a high-efficiency fuel. Simultaneously, hydrogen is an important chemical raw material. For instance, hydrogen and nitrogen can be directly synthesized into ammonia under high temperature, high pressure, and the presence of a catalyst. Currently, many processes in the petroleum industry require hydrogen, such as hydrocracking, hydrorefining, hydrodesulfurization, and catalytic hydrogenation.

[0003] With the advent of the new energy era, the demand for hydrogen is becoming increasingly prominent. For regions without convenient hydrogen sources, the traditional method of producing hydrogen by separating hydrogen from petroleum, natural gas, or coal requires huge investments. For small and medium-sized users, water electrolysis can easily produce hydrogen, but it consumes a lot of energy, produces hydrogen with low purity and many impurities, and its scale is also limited. Therefore, there is a need to develop a hydrogen production method that uses easily transportable raw materials, produces high-purity hydrogen, has low equipment construction costs, and low energy consumption, in order to expand the application range of hydrogen. Summary of the Invention

[0004] Based on this, the present invention provides a method for producing hydrogen from methanol, which has the advantages of easy transportation of raw materials, high purity of produced hydrogen, low equipment construction cost, and low energy consumption, thereby achieving the goal of expanding the application range of hydrogen.

[0005] A method for producing hydrogen from methanol, comprising the following steps:

[0006] S10: The methanol-water mixture is heated to vaporize it and obtain methanol-water vapor.

[0007] S20: Methanol steam is fed into the methanol reforming reactor to react and produce a hydrogen mixture.

[0008] S30: After cooling the hydrogen mixture, the unreacted methanol water is absorbed in the water washing tower. Then, the relative humidity and temperature of the hydrogen mixture are adjusted. At this time, the volume percentage of each component in the hydrogen mixture is: carbon monoxide 0-1%, carbon dioxide 24%-25%, and hydrogen 74%-75%.

[0009] S40: The hydrogen-gas mixture is fed into the carbon dioxide absorption tower, and the decarbonization liquid is sprayed to absorb the carbon dioxide in the hydrogen-gas mixture.

[0010] S50: After removing carbon dioxide, product hydrogen is obtained and stored in a hydrogen tank for supply to users.

[0011] The above-described methanol-to-hydrogen method involves reforming methanol with steam to produce a hydrogen mixture. This mixture is then purified to yield hydrogen with very low carbon monoxide content. This method offers advantages such as easy transport of raw materials, high purity of the produced hydrogen, low equipment construction costs, and low energy consumption, thus expanding the application range of hydrogen.

[0012] In one embodiment, in step S30, before entering the water washing tower, the hydrogen mixture is fed into a heat exchanger to pre-exchange heat with the methanol-water mixture for cooling. Utilizing the heat exchanger to achieve heat exchange between the methanol-water mixture and the hydrogen mixture not only cools the hydrogen mixture but also utilizes its thermal energy to preheat the methanol-water mixture, reducing the energy consumption of the methanol-water heating process in step S10, achieving heat energy recovery and utilization, and ultimately reducing overall energy consumption.

[0013] In one embodiment, in step S30, the relative humidity and temperature of the hydrogen mixture are adjusted by: inputting the hydrogen mixture into a buffer tank for cooling, so that the water vapor in the hydrogen mixture is liquefied, and controlling the relative humidity and temperature of the gas outlet of the buffer tank.

[0014] In one embodiment, after adjusting the relative humidity and temperature in step S30, the relative humidity of the hydrogen mixture is ≤80% and the temperature is 40℃~50℃.

[0015] In one embodiment, in step S40, the pressure inside the carbon dioxide absorption tower is 300 kPa to 800 kPa, and the temperature of the decarbonization liquid is 40°C to 55°C.

[0016] In one embodiment, in step S40, the weight ratio of each component in the decarbonization liquid is: ethanolamine 10%–30%, anhydrous piperazine 4%–8%, sodium metavanadate 0%–0.8%, and the remainder is deionized water.

[0017] In one embodiment, step S40 further includes: conveying the decarbonized liquid after absorbing carbon dioxide to the desorption tower for desorption and regeneration; the desorbed carbon dioxide is cooled and then stored in a carbon dioxide storage tank or vented; and the regenerated decarbonized liquid is returned to the carbon dioxide absorption tower.

[0018] In one embodiment, the regenerated decarbonized liquid is cooled before being returned to the carbon dioxide absorber.

[0019] In one embodiment, the temperature of the decarbonized liquid after cooling is 40°C to 55°C.

[0020] In one embodiment, the pressure inside the analytical column is 0–300 kPa and the temperature is 100°C–115°C. Attached Figure Description

[0021] Figure 1 This is a flowchart of a methanol-to-hydrogen method according to an embodiment of the present invention. Detailed Implementation

[0022] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0027] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0028] like Figure 1 As shown, this is an embodiment of the methanol-to-hydrogen method of the present invention.

[0029] like Figure 1 As shown, the methanol-to-hydrogen method includes the following steps:

[0030] S10: The methanol-water mixture is heated to vaporize it and obtain methanol-water vapor.

[0031] Methanol-water is a raw material for hydrogen production; it is inexpensive and easy to transport. Methanol-water is heated to produce methanol-water vapor. For example, methanol-water can be stored in a raw material storage tank and then pumped to a methanol-water vaporization chamber (also called a methanol-water evaporator) for vaporization, yielding methanol-water vapor.

[0032] S20: Methanol steam is fed into the methanol reforming reactor to react and produce a hydrogen mixture.

[0033] S30: After cooling the hydrogen mixture, the unreacted methanol water is absorbed in the water washing tower. Then, the relative humidity and temperature of the hydrogen mixture are adjusted. At this time, the volume percentage of each component in the hydrogen mixture is: carbon monoxide 0-1%, carbon dioxide 24%-25%, and hydrogen 74%-75%.

[0034] A water washing tower can wash the hydrogen mixture to absorb any unreacted methanol-water residue. Water is then removed from the hydrogen mixture by adjusting relative humidity and temperature. For example, in this embodiment, in step S30, the volume ratio of the components in the resulting hydrogen mixture is: carbon monoxide 1%, carbon dioxide 24.5%, and hydrogen 74.5%.

[0035] In this embodiment, after adjusting the relative humidity and temperature in step S30, the relative humidity of the hydrogen mixture is ≤80% and the temperature is 40℃~50℃.

[0036] When methanol vapor is fed into the methanol reforming reactor, it reacts to produce a high-temperature hydrogen mixture. At this point, the heat energy of the hydrogen mixture can be recovered and used to heat the methanol-water mixture in step S10, achieving heat energy recovery and utilization, thus reducing energy consumption. For example, in step S30, before entering the water washing tower, the hydrogen mixture is fed into a heat exchanger to pre-exchange heat with the methanol-water mixture for cooling (i.e., a heat exchanger for preheating is installed before the methanol-water vaporization chamber, which facilitates heat exchange between the methanol-water mixture and the hydrogen mixture). Utilizing the heat exchanger to achieve heat exchange between the methanol-water mixture and the hydrogen mixture not only cools the hydrogen mixture but also utilizes its heat energy to preheat the methanol-water mixture, reducing the energy consumption of the methanol-water heating process in step S10, achieving heat energy recovery and utilization, and ultimately reducing overall energy consumption.

[0037] There are various ways to adjust the relative humidity and temperature of the hydrogen mixture. For example, in this embodiment, in step S30, the relative humidity and temperature of the hydrogen mixture are adjusted by: feeding the hydrogen mixture into a buffer tank for cooling, causing the water vapor in the hydrogen mixture to liquefy, and controlling the relative humidity and temperature at the gas outlet of the buffer tank.

[0038] S40: The hydrogen-to-carbon dioxide mixture is fed into the carbon dioxide absorption tower, and the decarbonization liquid is sprayed to absorb the carbon dioxide in the hydrogen-to-carbon dioxide mixture.

[0039] Because the hydrogen mixture obtained from the methanol reforming reaction contains a relatively high amount of carbon dioxide, it is necessary to purify the hydrogen mixture to remove the carbon dioxide in order to obtain hydrogen with higher purity. In a carbon dioxide absorption tower, decarbonization liquid is sprayed down from the top of the tower to absorb the carbon dioxide in the hydrogen mixture.

[0040] In this embodiment, in step S40, the pressure inside the carbon dioxide absorption tower is 300 kPa to 800 kPa, and the temperature of the decarbonization liquid is 40°C to 55°C.

[0041] In this embodiment, in step S40, the weight ratio of each component in the decarbonization solution is: ethanolamine 10%–30%, anhydrous piperazine 4%–8%, sodium metavanadate 0–0.8%, and the remainder is deionized water. Ethanolamine is the main absorbent, piperazine is the co-absorbent, and sodium metavanadate is the corrosion inhibitor.

[0042] Furthermore, to establish a hydrogen-mixed gas purification system capable of cyclic operation, the decarbonized liquid after absorbing carbon dioxide can be regenerated through analysis and then returned to the carbon dioxide absorption tower. For example, in this embodiment, step S40 further includes: conveying the decarbonized liquid after absorbing carbon dioxide to an analysis tower for analysis and regeneration; the analyzed carbon dioxide is cooled and then stored in a carbon dioxide storage tank or vented; and the regenerated decarbonized liquid is returned to the carbon dioxide absorption tower. After absorbing carbon dioxide, the decarbonized liquid can be conveyed to the analysis tower for regeneration through pressure differential. The regenerated decarbonized liquid is then transported back to the carbon dioxide absorption tower via a circulation pump.

[0043] The pressure inside the analytical tower is 0–300 kPa, and the temperature is 100–115 °C.

[0044] Furthermore, since the temperature of the regenerated decarbonized liquid is higher than that of the decarbonized liquid in the carbon dioxide absorption tower, in order to improve the carbon dioxide absorption effect, the temperature of the regenerated decarbonized liquid can be cooled to match the temperature of the decarbonized liquid in the carbon dioxide absorption tower. For example, in this embodiment, the regenerated decarbonized liquid is cooled before being returned to the carbon dioxide absorption tower. For example, the temperature of the cooled decarbonized liquid is 40°C to 55°C.

[0045] S50: After removing carbon dioxide, product hydrogen is obtained and stored in a hydrogen tank for supply to users.

[0046] After carbon dioxide removal treatment, the carbon dioxide removal rate is ≥99%, and the resulting hydrogen mixture is product hydrogen containing low carbon monoxide.

[0047] The above-described methanol-to-hydrogen method involves reforming methanol with steam to produce a hydrogen mixture. This mixture is then purified to yield hydrogen with very low carbon monoxide content. This method offers advantages such as easy transport of raw materials, high purity of the produced hydrogen, low equipment construction costs, and low energy consumption, thus expanding the application range of hydrogen.

[0048] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0049] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A method for producing hydrogen from methanol, characterized by, The method comprises the steps of: S10: heating the methanol water to vaporize the methanol water to obtain methanol water vapor; S20: inputting the methanol water vapor into a methanol reforming reactor to obtain a hydrogen mixture gas; S30: after cooling treatment, absorbing unreacted methanol water through a water washing tower, then adjusting the relative humidity and temperature of the hydrogen mixture gas to make the relative humidity of the hydrogen mixture gas ≤80% and the temperature 40-50°C; at this time, the volume ratio of each component in the hydrogen mixture gas is: carbon monoxide 0-1%, carbon dioxide 24-25%, and hydrogen 74%; S40: inputting the hydrogen mixture gas into a carbon dioxide absorption tower, spraying a decarburization liquid to absorb carbon dioxide in the hydrogen mixture gas to make the carbon dioxide removal rate ≥99%; The pressure in the carbon dioxide absorption tower is 300-800 KPa; the temperature of the decarburization liquid is 40-55°C, and the weight ratio of each component in the decarburization liquid is: ethanolamine 10-30%, anhydrous piperazine 4-8%, sodium metavanadate 0-0.8%, and the rest is deionized water; the decarburization liquid after absorbing carbon dioxide is transported to a desorption tower for desorption and regeneration; the pressure in the desorption tower is 0-300 KPa, and the temperature is 100-115°C; the desorbed carbon dioxide is cooled and stored in a carbon dioxide storage tank or discharged; the regenerated decarburization liquid is cooled to 40-55°C and then returned to the carbon dioxide absorption tower; S50: after removing the carbon dioxide, product hydrogen is obtained and input into a hydrogen tank for storage to supply a user end.

2. The method of claim 1, wherein, In step S30, before entering the water washing tower, the hydrogen mixture gas is input into a heat exchanger to pre-heat with the methanol water to achieve cooling treatment.

3. The method of claim 1, wherein the methanol is provided at a temperature of 20- 30°C. In step S30, the relative humidity and temperature of the hydrogen mixture gas are adjusted by inputting the hydrogen mixture gas into a buffer tank for cooling to liquefy the water vapor in the hydrogen mixture gas, and controlling the relative humidity and temperature of the gas outlet of the buffer tank.

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