In 2017, many steel company enlarged their oxygen capacity and invest to build large oxygen plants. One of the efficient and popular oxygen generating methods is VPSA oxygen technology.

PSA oxygen technology is one of the air separating technology for oxygen booming in recent ten years. Compared with traditional cryogenic technology, PSA oxygen technology is known for its low investment, low consumption, low operation-maintenance fee, mild process conditions, simple process flow, high automation, high operation flexibility, short construction duration, and safe performance. Up to now, PSA oxygen technology can replace cryogenic in many circumstances, and the PSA oxygen technology is more economic than cryogenic in running.

The main components of air are nitrogen and oxygen, so oxygen can be generated through a selective adsorbent which can separate oxygen from nitrogen in a suitable operation condition. In a pressurized condition, when air flows through adsorption beds with zeolites, nitrogen will be largely adsorbed, while little oxygen will be adsorbed, thus oxygen get enriched. When adsorbent is close to saturation, air will be stopped feeding into the bed, and will get desorbed after pressure get released, in which adsorbent get recycled. Two adsorption beds work in turns to get continual oxygen.

We can know from the principles above that PSA oxygen technology must contain two steps: one is adsorption (high pressure in relative) and the other is desorption (low pressure in relative), and such two steps repeat in turns. So, if there is only one adsorption bed, the oxygen is generated discontinuously. In order to get oxygen continuously, two adsorption beds are set in the process. Additionally, from the point of consumption and stability, some other assisted steps are also included into the process, such as equalization and purge.

According to desorption pressure, there are two specific PSA oxygen technology:

1. PSA Process: Pressurized adsorption (0.2~0.6MPa) and ordinary pressure desorption. This technology has a simple process and low investment, but low recovery rate and high consumption, so it is best for small plant (