When the hydrogen from the ammonia decomposition plant is qualified, the hydrogen is purified for further purification. The purity of the cracked hydrogen is very high, with only trace amounts of ammonia and water as the volatile impurities. 

The gas purification is carried out by variable temperature adsorption technology. Variable temperature adsorption (TSA) is a gas separation and purification process based on the different adsorption properties of gas molecules on the internal surface of the adsorbent (porous solid material) at different temperatures. The surface of molecular sieve is full of microporous, which can be adsorbed at room temperature and pressure equivalent to 20% of its own weight (water and impurities during static adsorption, while at 350℃ or so, it can be completely regenerated and switched every 24 hours to get the product gas with qualified purity and impurity content. The absorption towers are used in parallel and alternately with two towers, allowing for continuous gas supply.