Ammonia (gaseous) is cracked into 75% hydrogen and 25% nitrogen under the action of a catalyst (Southwest Institute Z204) at a certain temperature, and absorbs 21.9 kcal of heat. The main reaction is: 2NH3-3H2+N2-21.9 kcal Because the process is an endothermic expansion reaction, increasing the temperature is conducive to ammonia cracking, and at the same time it is a volume expansion reaction, reducing the pressure is conducive to the decomposition of ammonia, and the ammonia decomposition hydrogen production equipment is in the best state.