Coal hydrogen production is based on coal as a reducing agent and water vapor as an oxidant. At high temperature, carbon is converted into CO and H2-based syngas, and then hydrogen is produced through gas purification, CO conversion and H2 purification. Coal can be subjected to various vaporization treatments, such as fluidized bed, jet bed, fixed bed, etc., to achieve hydrogen production from coal. The basic principle of hydrogen production from coal can be expressed by chemical reaction equation. The chemical reaction process is : C ( s ) + H2O + heat → CO + H2
This reaction process is an endothermic process. The reforming process requires additional heat, and the heat released by coal and air combustion provides the heat required for the reaction. The CO in the product is further converted into CO2 and H2 by water vapor transfer reaction : CO + H2O → CO2 + H2 + heatThe technology of hydrogen production from coal has been quite mature and has been commercialized. However, this process of hydrogen production is complicated and the cost of hydrogen production is high. The CO2 produced in the preparation process can cause the greenhouse effect of the earth. However, due to the abundant coal reserves in the world, this method is still the main method for hydrogen production.