I. Brief introduction of ammonia decomposition hydrogen production process:
Using liquid ammonia as a raw material, after ammonia cracking, ammonia cracking per kilogram of liquid can produce a mixed gas of 2.64 Nm3, which contains 75% hydrogen and 25% nitrogen. The obtained gas contains less impurities (about 2 g/m3 of water vapor in the impurities, about 1000 ppm of residual ammonia), and then passes through a molecular sieve (UOP) adsorption purifier, and the dew point of the gas can be reduced to below -60 ° C, and the residual ammonia can be Reduced to below 3PPM. Ammonia cracking hydrogen furnace can be used for bright annealing of metallic materials and parts such as non-ferrous metals, silicon steel, chrome steel and stainless steel, decarburization of silicon steel sheets, copper-based, iron-based powder metallurgy sintering, and electric vacuum devices. Hydrogen treatment of metal parts, protection sintering and sealing of semiconductor devices, and diffusion of purified raw material gas of hydrogen by palladium alloy film.
The raw material ammonia is easy to obtain, the price is low, and the raw material consumption is small. Ammonia cracking to obtain protective gas has the advantages of low investment, small volume and high efficiency.
Second, ammonia decomposition hydrogen production working principle:
At a certain temperature, ammonia (gaseous) cracks 75% of hydrogen and 25% of nitrogen by catalyst, and absorbs 21.9 kcal of heat. The main reaction is: 2NH3=3H2+N2-21.9 kcal, the whole process It is an endothermic expansion reaction. Increasing the temperature is beneficial to ammonia cracking. At the same time, it is a volume-enlarged reaction. The pressure reduction is beneficial to the decomposition of ammonia. The ammonia decomposition hydrogen production equipment is in an optimal state.
Third, the working principle of hydrogen purification:
When the hydrogen produced by the ammonia decomposition hydrogen production equipment is qualified, it is further purified by hydrogen purification for further purification. The purity of the cracked hydrogen is high, and the volatile impurities have only a trace amount of residual ammonia and water, and it is only necessary to remove a trace amount of residual ammonia and moisture. High purity gas is available.
Gas purification uses temperature swing adsorption technology. Temperature swing adsorption (TSA) technology is a gas separation and purification process based on adsorbent (porous solid matter) and internal surface on the adsorption performance of gas molecules at different temperatures. The impurity gas is adsorbed at normal temperature, and the impurity gas is removed when heated. The surface of the molecular sieve is all microporous, and the moisture and impurities corresponding to 20% static weight can be adsorbed at normal temperature and pressure, and at a temperature of about 350 ° C, It can be completely regenerated and switched every 24 hours to obtain a product gas with acceptable purity and impurity content.
