The purity issue of pre-hydrogenated recycle hydrogen?
Thread Content
Why is the purity of the pre-hydrogenated recycle hydrogen higher than that of the make-up hydrogen coming after reprocessing and recollection? 1. During the pre-hydrogenation reaction, impurities such as H2S, NH3, and H2O are generated. 2. The initial purity of the hydrogen supplied after reformation is 91%, while the purity of the recycle hydrogen used in pre-hydrogenation is 96%-98%. Please help to explain this, experts~
The low purity of the reformed hydrogen is mainly due to the relatively low pressure of the hydrogen delivered from continuous reforming processes, which is around 1.5 MPa. When this hydrogen enters the pre-hydrogenation system, impurities such as hydrogen sulfide and ammonia are added; however, the light hydrocarbon components C1-C4, which have a significant impact on purity, are separated from the gas phase in the pre-hydrogenation cold separation tank (where the pressure is 3.2 MPa, much higher than that in the recapture tank), and their proportion is greatly reduced as a result, thereby improving the purity of the hydrogen. This is also why it is said that the one-pass reformation pre-hydrogenation process yields hydrogen of higher purity compared to the circulating hydrogen process. Personal opinion~~