A method for dehydrogenation of high concentration carbon monoxide

Abstract

The application discloses a method for dehydrogenation of high-concentration carbon monoxide gas, at least two catalytic converters are set up, at least one active-state converter is called a working tower, raw gas containing hydrogen ≤1%, carbon monoxide ≥99% and pressure ≥0.3MPa is sent in, the working tower is filled with active-state composite catalyst, the reaction of the composite catalyst is combination of three types of catalysts, namely, Fischer-Tropsch catalyst, shift catalyst and carbon dioxide absorption catalyst; the composite catalyst converts hydrogen and carbon monoxide into hydrocarbons, alcohols, ethers and carbonates, pressure ≥0.25MPa and hydrogen concentration reduced to below 50ppm are called dehydrogenated gas, the dehydrogenated gas is sent to a pressure swing adsorption device to purify carbon monoxide, the obtained product carbon monoxide gas has a concentration of above 99.9% and hydrogen concentration below 50ppm; when hydrogen concentration in the dehydrogenated gas is above 50ppm, the working tower becomes an activation tower, raw gas is switched to another working tower; the activation tower uses high-temperature steam to remove generated elemental carbon into gas to escape, heats and decomposes carbonates into oxides and carbon dioxide to escape, thereby recovering catalytic activity, the activation tower recovering catalytic activity becomes a working tower; and the method realizes the purpose of continuous conversion and hydrogen removal through cyclic operation.

Description

Technical Field

[0001] This invention relates to the field of gas purification, and in particular to the removal of trace amounts of hydrogen from high concentrations of carbon monoxide gas. Background Technology

[0002] As is well known, industrial feedstock gases used for carbon monoxide separation include: syngas from natural gas and petroleum conversion, water gas, semi-water gas, and tail gas from steel plants, calcium carbide plants, and yellow phosphorus plants. The main existing method for carbon monoxide separation and purification is pressure swing adsorption (PSA). Several companies in my country have developed new PSA technologies for carbon monoxide separation, especially highly efficient adsorbents with extremely high adsorption capacity and selectivity for carbon monoxide. This can solve the problem of separating high-purity carbon monoxide from feedstock gases with high nitrogen or methane content, and allows for the design and construction of large-scale carbon monoxide separation and purification units.

[0003] Currently, the dehydrogenation catalysts reported domestically and internationally mainly include Pd / Al2O3 and CoMo / Al2O3, as well as dehydrogenation agents based on manganese-based metal oxides. However, these catalysts or dehydrogenation agents are generally used for the dehydrogenation and purification of non-reducing gases such as high-purity nitrogen, high-purity oxygen, and carbon dioxide. In the presence of carbon monoxide reducing gas, these catalysts exhibit low hydrogen removal rates and high carbon monoxide loss rates. Chinese National Invention Patent CN971918058 discloses a method and catalyst for catalytic oxidative dehydrogenation, using a carbon monoxide mixture with a hydrogen content of 10% as raw material, at a reaction temperature of 220℃ and a volume hourly space velocity of 3000 h⁻¹. -1 Under conditions of an oxygen / hydrogen molar ratio of 0.6:1 and a reaction pressure of 0.5 MPa, the carbon monoxide loss rate reached as high as 1.5%, and the hydrogen content in the reaction effluent reached as high as 1000 ppm. Chinese National Invention Patent CN201110045473 discloses a method for the oxidative dehydrogenation of a raw material containing carbon monoxide gas. By using carbon monoxide-containing gas as a raw material, and at a reaction temperature of 80–180 °C and a volume hourly space velocity of 100–10000 h⁻¹, the method achieves the desired dehydrogenation. -1 Under conditions where the oxygen / hydrogen molar ratio is 0.5–10:1 and the reaction pressure is -0.08–5.0 MPa, the raw material comes into contact with a noble metal catalyst, and the hydrogen in the raw material is oxidized to water. The key feature is that the noble metal catalyst uses palladium as the active component, manganese as an auxiliary agent, and alumina as a support. The catalyst comprises 0.003–2 parts by weight of palladium, 0.005–15 parts by weight of manganese, and 40–99.5 parts by weight of alumina. This technical solution effectively solves the problem, removing 100% of the hydrogen from the raw material while achieving a carbon monoxide loss rate of less than 0.4%, thus achieving good technical results.

[0004] Nevertheless, the above technologies all employ catalytic oxidation dehydrogenation with the participation of oxygen. In contrast, this invention removes a small amount of hydrogen from high-concentration carbon monoxide gas in the absence of oxygen. This invention not only solves the technical problems of low hydrogen removal rate and high carbon monoxide loss rate in previous literature, but also provides a new method for dehydrogenating carbon monoxide-containing gas. Summary of the Invention

[0005] The technical solution adopted in this invention is as follows: At least two catalytic converters are set up, at least one of which is called the working tower, which is fed with feed gas containing ≤1% hydrogen, ≥99% carbon monoxide, and a pressure ≥0.3MPa. The working tower is filled with an activated composite catalyst, which is a combination of three types of catalysts: Fischer-Tropsch catalyst, shift catalyst, and carbon dioxide absorption catalyst. The composite catalyst converts hydrogen and carbon monoxide into hydrocarbons, alcohols, ethers, and carbonates. When the pressure is ≥0.25MPa and the hydrogen concentration is reduced to below 50ppm, it is called dehydrogenated gas, which is then sent to a pressure swing adsorption unit to purify carbon monoxide. The resulting product has a carbon monoxide concentration of ≥99.9% and a hydrogen concentration of less than 50ppm. When the hydrogen concentration in the dehydrogenated gas is higher than 50ppm, the working tower becomes the tower to be activated, and the feed gas is switched to another tower to be activated. The tower to be activated uses high-temperature steam to remove the generated elemental carbon as gas, and then heats and decomposes the carbonates into oxides and carbon dioxide, thereby restoring catalytic activity. The tower to be activated with restored catalytic activity becomes the tower to be activated. The cycle operation achieves the purpose of continuous conversion and removal of hydrogen.

[0006] The technical solution of this invention can remove hydrogen from carbon monoxide gas to below 50 ppm. The invention is further illustrated below by examples, but is not limited to these examples. Detailed Implementation

[0007] Example 1: Two catalytic converters are set up, and a feed gas containing 0.3% hydrogen and 99.7% carbon monoxide at a pressure of 0.3 MPa is fed in. The working column is filled with a Fischer-Tropsch catalyst, a shift catalyst, and a carbon dioxide absorption catalyst. This composite catalyst reacts hydrogen and carbon monoxide into hydrocarbons, alcohols, ethers, and carbonates. The dehydrogenated gas is then sent to a pressure swing adsorption unit to purify the carbon monoxide. The resulting product has a carbon monoxide concentration of over 99.9% and a hydrogen concentration of 45 ppm. When the hydrogen concentration in the dehydrogenated gas exceeds 50 ppm, the working column becomes a column to be activated, and the feed gas is switched to another column to be activated. The column to be activated uses high-temperature steam to remove the generated elemental carbon, which escapes as gas. Heating decomposes the carbonate into oxides and carbon dioxide, thereby restoring catalytic activity. The column to be activated with restored catalytic activity becomes the column to be activated. This cyclical operation achieves the purpose of continuous conversion and dehydrogenation of hydrogen.

[0008] Example 2: Three catalytic converters are set up, and a feed gas containing 0.5% hydrogen and 99.5% carbon monoxide at a pressure of 0.5 MPa is fed in. The working column is filled with a Fischer-Tropsch catalyst, a shift catalyst, and a carbon dioxide absorption catalyst. This composite catalyst reacts hydrogen and carbon monoxide into hydrocarbons, alcohols, ethers, and carbonates. The dehydrogenated gas is then sent to a pressure swing adsorption unit to purify the carbon monoxide. The resulting product has a carbon monoxide concentration of over 99.9% and a hydrogen concentration of 35 ppm. When the hydrogen concentration in the dehydrogenated gas exceeds 50 ppm, the working column becomes a column to be activated, and the feed gas is switched to another column to be activated. The column to be activated uses high-temperature steam to remove the generated elemental carbon, which escapes as gas. Heating decomposes the carbonate into oxides and carbon dioxide, thereby restoring catalytic activity. The column to be activated with restored catalytic activity becomes a column to be activated. This cyclical operation achieves the purpose of continuous conversion and dehydrogenation of hydrogen.

[0009] Example 3: Five catalytic converters are set up, and a feed gas containing 1.0% hydrogen and 99.0% carbon monoxide at a pressure of 5.0 MPa is fed in. The working column is filled with a Fischer-Tropsch catalyst, a shift catalyst, and a carbon dioxide absorption catalyst. This composite catalyst reacts hydrogen and carbon monoxide into hydrocarbons, alcohols, ethers, and carbonates. The dehydrogenated gas is then sent to a pressure swing adsorption unit to purify the carbon monoxide. The resulting product has a carbon monoxide concentration of over 99.9% and a hydrogen concentration of 40 ppm. When the hydrogen concentration in the dehydrogenated gas exceeds 50 ppm, the working column becomes a column to be activated, and the feed gas is switched to another column to be activated. The column to be activated uses high-temperature steam to remove the generated elemental carbon, which escapes as gas. Heating decomposes the carbonate into oxides and carbon dioxide, thereby restoring catalytic activity. The column to be activated with restored catalytic activity becomes a column to be activated. This cyclical operation achieves the purpose of continuous conversion and dehydrogenation of hydrogen.

Claims

1. A method for dehydrogenation of a high concentration carbon monoxide gas, characterized by At least two catalytic converters are set up, at least one of which is called working tower, and the raw material gas containing hydrogen ≤1%, carbon monoxide ≥99% and pressure ≥0.3MPa is sent in, the working tower is filled with activated composite catalyst, the reaction of the composite catalyst is composed of three types of catalysts, namely Fischer-Tropsch catalyst, shift catalyst and carbon dioxide absorption catalyst; the composite catalyst converts hydrogen and carbon monoxide into hydrocarbons, alcohols, ethers and carbonates, the pressure is ≥0.25MPa, the hydrogen concentration is reduced to below 50ppm, which is called dehydrogenation gas, and then sent to a pressure swing adsorption device to purify carbon monoxide, thereby obtaining product carbon monoxide gas with a concentration of 99.9% or more and a hydrogen concentration of less than 50ppm; when the hydrogen concentration in the dehydrogenation gas is higher than 50ppm, the working tower becomes an activation tower, and the raw material gas is switched to another working tower; the activation tower uses high-temperature steam to remove the generated elemental carbon into gas and escape, and heats and decomposes the carbonates into oxides and carbon dioxide to escape, thereby restoring the catalytic activity, and the activated tower that has restored the catalytic activity becomes a working tower; the purpose of continuous conversion and removal of hydrogen is achieved through cyclic operation.