Method for producing electronic grade hydrogen cogeneration of LNG from coke oven gas

Abstract

The application discloses a method for producing electronic-grade hydrogen and co-producing LNG from coke oven gas, and the method comprises cryogenic rectification purification, PSA hydrogen production purification and purifier purification, the cryogenic rectification comprises compression, precooling and rectification, the PSA hydrogen production purification comprises a pressure swing adsorption process and a deoxidization and drying process, and the purifier purification comprises an adsorption and regeneration process. The application realizes comprehensive utilization of coke oven gas, production of electronic-grade hydrogen and LNG products, and improvement of the economic value of the coke oven gas.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for producing hydrogen and co-producing LNG, more specifically, to a method for producing electronic-grade hydrogen and co-producing LNG from coke oven gas, and belongs to the field of coke oven gas utilization. BACKGROUND

[0002] High-purity hydrogen has important applications in the electronic industry, and is required in the growth of crystals and the preparation of substrates, oxidation processes, epitaxy processes, and chemical vapor deposition. In the process of manufacturing semiconductor devices, the purity of hydrogen is of great significance to the quality and performance of chips, and the purity of hydrogen needs to be strictly controlled to ensure the quality and reliability of products.

[0003] At present, using coke oven gas for power generation is an uneconomical treatment method and pollutes the environment to some extent. The traditional process is limited to hydrogen production from coke oven gas or LNG production from coke oven gas, and the separate production of one product results in the waste of another product, so the value of coke oven gas cannot be fully utilized. SUMMARY

[0004] In order to solve the above-mentioned prior art problems, the present application provides a method for producing electronic-grade hydrogen and co-producing LNG from coke oven gas, which has the technical characteristics of being able to produce electronic-grade hydrogen and co-produce LNG, improving the utilization value of coke oven gas, reducing pollutant emissions, protecting the environment, and amplifying economic benefits.

[0005] In order to achieve the above-mentioned purpose, the present application is realized by the following technical scheme:

[0006] A method for producing electronic-grade hydrogen and co-producing LNG from coke oven gas, the method comprising the following steps:

[0007] Step 1) purification treatment: purifying the coke oven gas, compressing it to 0.4-1.2 MPa by a compressor, and sending it into a temperature swing adsorption device to remove harmful components in the raw gas, and then entering step 2); the harmful components include tar, benzene, naphthalene, sulfides, alkanes, and aromatic hydrocarbons;

[0008] Step 2) cryogenic rectification purification: the cryogenic rectification purification includes compression, precooling, and rectification by passing in liquid nitrogen to obtain LNG products and hydrogen-rich gas, the LNG products are collected, and the hydrogen-rich gas enters step 3);

[0009] Step 3) PSA hydrogen production purification: the PSA hydrogen production purification includes pressure swing adsorption and deoxygenation drying, and after PSA hydrogen production purification, it enters step 4);

[0010] Step 4) purifier purification: the purifier purification is hydrogen purification to obtain electronic-grade H2 products.

[0011] Preferably, step 2) is specifically: the purified coke oven gas is sent into a compressor for compression, cooled and separated from water in precooling after obtaining the actual required pressure, sent into a cold box for cooling to the actual set temperature through a heat exchanger, and then sent into a rectification tower for rectification, and liquid nitrogen is poured from the top of the rectification tower for participating in the rectification process, the LNG product is obtained at the bottom of the rectification tower, and the hydrogen-rich gas is obtained at the top of the rectification tower, which is reheated through the heat exchanger and sent to the cold box.

[0012] Preferably, step 3) is specifically: high-pressure adsorption and low-pressure desorption in a PSA hydrogen extraction device, and 99.999% high-purity hydrogen gas is obtained through pressure swing adsorption, but there is still a small amount of oxygen, the high-purity hydrogen gas is sent into a deoxidizing and drying device, oxygen reacts with hydrogen to generate water under the action of a deoxidizing catalyst, the oxygen in the gas is removed, and the hydrogen gas is cooled to room temperature through a hydrogen cooler and then enters a drying machine system for deep dehydration.

[0013] Preferably, step 4) is specifically: the hydrogen gas from which the oxygen and water are removed is sent to a hydrogen ultra-low temperature purifier for purification treatment, through an adsorption tower soaked in liquid nitrogen, impurities in the hydrogen gas are adsorbed due to solidification or liquefaction at low temperature, and the hydrogen gas still flows out in the form of gas, and 99.9999999% purity electronic-grade hydrogen gas is obtained through purification.

[0014] Preferably, the hydrogen purifier in step 4) uses a low-temperature purifier, liquid nitrogen is used as a cold source to soak the adsorption tower, and the hydrogen gas purification removes impurities including CO, CO2, NMHC, CH4, N2 and Ar.

[0015] Beneficial effects: the coke oven gas can be comprehensively utilized to produce electronic-grade hydrogen gas and co-produce LNG, the energy is comprehensively utilized, the economic value of the coke oven gas is improved, the problems of the original process complexity and single product are solved, the process is simple and easy to implement, the on-site operation is simpler, and the value of the hydrogen gas is improved through the purification step. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a process schematic diagram of the present application. DETAILED DESCRIPTION

[0017] The present application is further described below in conjunction with the drawings of the specification, but the present application is not limited to the following examples.

[0018] The present application is creatively completed by mainly using the following process to produce electronic-grade hydrogen gas and co-produce LNG from coke oven gas.

[0019] Three purification processes: cryogenic rectification purification, hydrogen purification by PSA, and purifier purification. The cryogenic rectification includes compression, precooling, and rectification, and the hydrogen purification by PSA includes pressure swing adsorption and deoxygenation drying. The purifier purification includes adsorption and regeneration. Finally, electronic-grade hydrogen gas product is produced from the coke oven gas, and energy is comprehensively utilized to obtain LNG product.

[0020] As shown in Figure 1 is a specific embodiment of a method for producing electronic-grade hydrogen gas from coke oven gas and co-producing LNG, which is a method for producing electronic-grade hydrogen gas from coke oven gas and co-producing LNG, comprising the following steps:

[0021] Step 1) Purification treatment: The coke oven gas is purified and compressed to 0.4-1.2 MPa by a compressor, and then sent to a temperature swing adsorption device to remove harmful components in the raw gas, and then enters step 2); the harmful components include tar, benzene, naphthalene, sulfides, alkanes, and aromatic hydrocarbons;

[0022] Step 2) Cryogenic rectification purification: the cryogenic rectification purification includes compression, precooling, and rectification with liquid nitrogen to obtain LNG product and hydrogen-rich gas, and the LNG product is collected and the hydrogen-rich gas enters step 3);

[0023] Specifically, the purified coke oven gas is sent to a compressor to obtain the actual required pressure, cooled and separated from water in precooling, sent to a cold box and cooled to the actual set temperature by a heat exchanger, then sent to a rectification tower for rectification, and liquid nitrogen is poured from the top of the rectification tower to participate in the rectification process, and LNG product is obtained at the bottom of the rectification tower, and hydrogen-rich gas is obtained at the top of the rectification tower, and the hydrogen-rich gas is reheated by a heat exchanger and sent to the cold box; wherein the liquid nitrogen is sent to the rectification device as a cold source for rectification heat exchange;

[0024] Step 3) Hydrogen purification by PSA: the hydrogen purification by PSA includes pressure swing adsorption and deoxygenation drying, and after the hydrogen purification by PSA, it enters step 4); specifically, high-pressure adsorption and low-pressure desorption are carried out in the PSA hydrogen extraction device, and 99.999% high-purity hydrogen gas is obtained through pressure swing adsorption, but there is still a small amount of oxygen, the high-purity hydrogen gas is sent to a deoxygenation drying device, under the action of a deoxygenation catalyst, oxygen reacts with hydrogen gas to generate water, the oxygen in the gas is removed, and the hydrogen gas is cooled to room temperature by a hydrogen cooler, and then enters a drying machine system for deep dehydration.

[0025] Step 4) Purifier purification: the purifier purification is hydrogen purification, to obtain electronic grade H2 product. Specifically: the hydrogen gas after removing oxygen and moisture is sent to the hydrogen ultra-low temperature purifier for purification treatment, through the adsorption tower soaked by liquid nitrogen, the impurities in the hydrogen gas are adsorbed due to solidification or liquefaction at low temperature, and the hydrogen gas still flows out in the form of gas, and the electronic grade hydrogen gas with a purity of 99.9999999% is obtained. In step 4), the hydrogen purifier uses a low-temperature purifier, the adsorption tower is soaked by liquid nitrogen as a cold source, and the hydrogen gas is purified to remove impurities including CO, CO2, NMHC, CH4, N2 and Ar.

[0026] Finally, it should be noted that the present application is not limited to the above embodiments, but can have many variations. All variations that can be directly derived or inferred from the disclosure of the present application by those of ordinary skill in the art should be considered within the scope of the present application.

Claims

1. A method for producing electronic-grade hydrogen and co-producing LNG from coke oven gas, characterized in that... The method includes the following steps: Step 1) Purification treatment: The coke oven gas is purified by being compressed to 0.4-1.2 MPa by a compressor and then sent to a temperature-switching adsorption device to remove harmful components from the raw gas before proceeding to Step 2); the harmful components include tar, benzene, naphthalene, sulfides, alkanes, and aromatics. Step 2) Cryogenic distillation purification: The cryogenic distillation purification includes compression, precooling, and distillation with liquid nitrogen to obtain LNG product and hydrogen-rich gas. The LNG product is collected, and the hydrogen-rich gas enters step 3). Step 3) PSA hydrogen production and purification: The PSA hydrogen production and purification includes pressure swing adsorption and deoxygenation drying. After PSA hydrogen production and purification, the process proceeds to step 4). Step 4) Purification by purifier: The purifier purifies the gas to hydrogen, yielding electronic-grade H2 product; Step 2) Specifically: The purified coke oven gas is sent to the compressor for compression. After obtaining the actual required pressure, it is cooled and separated from the water in the precooling process. It is then sent to the cold box and cooled to the actual set temperature by the heat exchanger before being sent to the distillation column to participate in the distillation. Liquid nitrogen is injected from the top of the distillation column to participate in the distillation process. LNG product is obtained at the bottom of the distillation column, and hydrogen-rich gas is obtained at the top of the distillation column. The hydrogen-rich gas is reheated by the heat exchanger and sent to the cold box. Step 3) Specifically: High-pressure adsorption and low-pressure desorption are performed in the PSA hydrogen extraction unit. After pressure swing adsorption, 99.999% high-purity hydrogen is obtained. The high-purity hydrogen is sent to the deoxygenation drying unit. Under the action of the deoxygenation catalyst, oxygen and hydrogen react to produce water, removing oxygen from the gas. The gas is then cooled to room temperature by a hydrogen cooler and then enters the drying system for deep dehydration. Step 4) Specifically, the hydrogen gas, after being deoxygenated and dehydrated, is sent to a hydrogen cryogenic purifier for purification. Through an adsorption tower immersed in liquid nitrogen, impurities in the hydrogen gas are adsorbed due to solidification or liquefaction at low temperature, and the hydrogen gas still flows out in gaseous form, thus obtaining electronic-grade hydrogen gas with a purity of 99.9999999%.

2. The method for producing electronic-grade hydrogen and co-producing LNG from coke oven gas according to claim 1, characterized in that: In step 4), a low-temperature purifier is used for hydrogen purification. Liquid nitrogen is used as a cold source to soak the adsorption tower. The hydrogen purification removes impurities including CO, CO2, NMHC, CH4, N2, and Ar.

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