Air separation system's purification system

Air separation unit purification system

The adsorbers used in the purification system include vertical axial flow, horizontal double bed and vertical radial flow.

Vertical axial flow is mainly used for supporting air separation equipment below 10000 grade (with a diameter of 4.6m). The bed thickness is 1550 ∽ 2300mm. It can be arranged in double layers and single layers. The vertical axial flow adsorber has the best air distribution.

The horizontal double-layer bed is mainly used for supporting large and medium-sized air separation equipment. The bed thickness is 1150mm (molecular sieve) +350mm (aluminum glue).

The vertical radial flow adsorber can effectively use the internal space of the vessel, so that the area of the adsorption layer with the same diameter can be expanded by about 1.5 times, which can effectively reduce the height of the tower. At the same time, the floor area of the vertical installation method is small. Due to the uniform air flow distribution, unlike the horizontal adsorber, the amount of molecular sieve is reduced by 20% and the regeneration energy consumption is also saved by 20%.

However, the disadvantage of vertical radial flow is that the gas flow center is concentrated (sector), which makes it faster than horizontal penetration time (CO2 < 0.5ppm). The bed thickness is 1000mm+200mm, and the vertical radial flow can meet the configuration of air separation equipment above 20000 grade.

There are two ways of regeneration heating: electric heater and steam heater.

Steam heaters are horizontal (below 40000 grade), vertical (above 40000 grade), and vertical high-efficiency steam heaters (with high steam utilization rate and energy saving of 20%) are arranged as follows: one steam heater (with H2O leakage measuring point); Electric heaters (dual-use and one standby or one for use and one for standby) are connected in parallel (high temperature and low flow interlock stop setting to prevent burnout. The heating tube is made of 1Cr18Ni9Ti); Electric heater (meeting activation regeneration, 250 ∽ 300 ℃) is connected in parallel with steam heater; The electric heater is connected in series with the steam heater (when the steam temperature is low, it will cause large regeneration resistance).

The purification system also needs to be equipped with throttling regeneration pipeline to meet the start-up needs. In addition, a safety valve is set at the regeneration gas side and a safety valve is set at the steam heater side to prevent leakage or overpressure at the high pressure side of the equipment or valve and throttling overpressure.

The regeneration flow path is equipped with a manual butterfly valve to adjust the resistance, so as to make the main tower operate stably (or if it is not set, it is adjusted by the timing of the regulating valve set in the main pipe).