In the small water gas production of ammonia plant, the proportion of nitrogen to hydrogen ratio is table after adding the nitrogen, which smooths the operation and reduce the consumption of synthetic ammonia; In addition, it also use the refined nitrogen (99.99%) to protect the catalyst; With pure liquid nitrogen washing refined Hydrogen and nitrogen mixture, so that the inert gas (methane and hydrogen) is 
extremely small, the contact of carbon monoxide and oxygen are no more than 20PPm. The consumption of nitrogen wash and nitrogen are about 750m3/t ammonia. Oxygen is functioned as the evaporator of pulverized coal or heavy oil, nitrogen involved in the synthesis and function as raw materials for gas, and be the safety gas of device (catalyst coal protection will use 99.99% pure nitrogen).
