Traditional natural gas hydrogen production process
The process flow of hydrogen production from natural gas consists of four units: feed gas treatment, steam conversion, CO conversion and hydrogen purification.
(1) The feed gas treatment unit is mainly used for desulfurization of natural gas, and MnO and ZnO desulfurizers are used to remove H2S and SO2.The processing capacity of feed gas is large, so a large centrifugal compressor is selected when compressing feed gas.
(2) Steam conversion unit. Water vapor is used as oxidant to convert hydrocarbons under the action of nickel catalyst to obtain conversion gas for hydrogen production. The type and structure of reformer have their own characteristics, and the structure, thermal compensation mode and fixing mode of upper and lower gas collectors are also different. Although the heat exchangers in the convection section are set differently, the process operation parameters of high-temperature conversion and relatively low water carbon ratio are adopted in the steam conversion unit, which is conducive to improving the conversion depth and saving raw material consumption.
(3) CO conversion unit. The feed gas sent from the reformer contains a certain amount of Co. the function of transformation is to make co react with steam to generate CO2 and H2 in the presence of catalyst. According to the transformation temperature, the transformation process can be divided into high temperature transformation (350 ~ 400 ℃) and medium temperature transformation (lower than 300 ~ 350 ℃).In recent years, due to the emphasis on resource conservation, the two-stage conversion process setting of CO high-temperature conversion and low-temperature conversion has been adopted in the process setting of the conversion unit, so as to further reduce the consumption of raw materials.
(4) Hydrogen purification unit. In the process, each hydrogen production company has adopted the pressure swing adsorption (PSA) purification and separation system with low energy consumption to replace the decarbonization and purification system and methane chemical process with high energy consumption, so as to achieve the goal of energy saving and simplifying the process, and hydrogen with purity up to 99.9% can be obtained at the outlet of the unit.
Post time: Nov-10-2021
