The fractionator of air separation equipment is the core unit for air separation. Its internal structure is precise and complex. High-purity extraction of oxygen, nitrogen and other gases is realized through multi-stage separation. The main structure includes the following parts:
Tower body and packing layer
The fractionator usually consists of upper and lower sections (upper column and lower column). The column body is made of low-temperature resistant stainless steel, and the internal part is filled with high-efficiency structured packing (such as corrugated plate or wire mesh) or tray. The packing layer promotes the mass transfer and separation of oxygen and nitrogen by increasing the steam-liquid contact area. Packing material shall be resistant to low temperature brittleness to ensure stable operation at - 196 ℃.
Condensate evaporator
Located on the top of the upper column, it is the key heat exchange component of the fractionator. The structure is of double-casing type, with the inner pipe flowing liquid nitrogen and the outer pipe flowing gaseous oxygen. Liquid nitrogen evaporates and absorbs heat under low pressure to condense the nitrogen rising from the lower column into liquid nitrogen; At the same time, the gaseous oxygen in the outer tube is cooled and liquefied, and part of it returns to the column to maintain the rectification cycle. This process realizes the preliminary separation of nitrogen and oxygen and the recycle of cold energy.
Liquid distributor and collector
A liquid distributor is installed above the packing layer, and the return liquid is uniformly distributed to the packing surface through the spray device, so as to avoid the partial bias flow affecting the separation efficiency. A liquid collector is set at the bottom of the column to introduce the condensed liquid oxygen and liquid nitrogen into the storage tank or subcooler respectively to ensure the purity of the product.
Feed inlet and side draw outlet
Air inlet is set in the middle of the lower column, through which the air cooled by the heat exchanger enters the column. Argon fraction extraction outlet (large unit) is set on the side wall of the upper column to extract the mixture containing argon and send it to the argon column for further refining.
