In any industrial process of generating syngas, it is an essential link to use the progress of water gas shift reaction to convert CO into hydrogen. This reaction is a reversible exothermic reaction. The higher the temperature, the lower the corresponding equilibrium conversion. At the same time, this reaction is a typical catalytic reaction. When there is no catalyst, it is difficult to react at 700. In the presence of catalyst, the reaction temperature is greatly reduced. When using high temperature shift catalyst, the reaction temperature is 300 ~ 500 ° C; When the low temperature shift catalyst is used, the reaction temperature is 200-400 ° C (table 22). Because the reaction is an isomolecular reaction, the pressure has no effect on the reaction equilibrium, but the pressure operation can improve the production intensity and reaction rate. At the initial stage of the reaction, the process is far from the equilibrium limit and is controlled by kinetics. Increasing the temperature can greatly improve the reaction rate and improve the process efficiency. In the later stage of the reaction, the conversion of the process is limited by thermodynamic equilibrium. The thermodynamic equilibrium conversion at high temperature is relatively low. Therefore, in the later stage of the reaction, low temperature operation should be adopted to improve the CO conversion. The thermodynamic and kinetic characteristics of the process determine that the CO conversion process should adopt variable temperature operation. At the initial stage of the reaction, the process is far from the equilibrium limit and is controlled by kinetics. Increasing the temperature can greatly improve the reaction rate and improve the process efficiency. In the later stage of the reaction, the conversion of the process is limited by thermodynamic equilibrium. The thermodynamic equilibrium conversion at high temperature is relatively low. Therefore, in the later stage of the reaction, low temperature operation should be adopted to improve the CO conversion. The thermodynamic and kinetic characteristics of the process determine that the CO conversion process should adopt variable temperature operation. Due to the restriction of reaction balance, although CO is deeply converted after low-temperature water gas conversion, its content is still about 1%, which can not meet the use requirements of many subsequent processes. In industry, it is usually removed by some chemical reactions. The selective oxidation of CO and O2 in the presence of a large amount of hydrogen generates CO2, and hydrogen and O2 are also easy to react. Therefore, the process strictly depends on the reaction temperature and the type of catalyst [29301]. Another industrialized process is the hydrogenation of CO with a large amount of existing hydrogen directly on nickel based catalyst to produce methane. After water gas transformation and CO removal, the main components of the gas become H2 and CO2. In the synthetic ammonia industry, CO2 needs to be separated first. These CO2 can continue to react with ammonia generated by hydrogen in the subsequent section to generate ammonium bicarbonate, ammonium carbonate or urea and other chemical fertilizers to realize the maximum utilization of CO2. In this process, the separation technology of CO2 and H2 is mainly to ensure that CO2 can be recycled use. For hydrogen applications such as proton membrane fuel cells, only hydrogen is used instead of CO2. CO2 becomes useless emissions, which may need to be combined with other mineralization processes (such as the production of food grade calcium carbonate). However, in all processes of CO2 separation, it is a better way to use organic amine or methanol to absorb CO2. Especially in the process of CO2 absorption by methanol at low temperature, the solubility of many gases will become higher at low temperature. Only the solubility of hydrogen is not limited by temperature, and the lower the temperature, the lower the solubility. It shows a good selectivity for H2 separation. In the process of recovering CO2, on the premise of avoiding damage to hydrogen yield, try to avoid using expensive reagents (such as caustic soda) that can strongly combine with CO, so as to ensure the economy of the process.