Function of subcooler in distillation column

Conventional liquid air separation plants are cooled by isothermal throttling refrigeration and expander refrigeration, LNG cold energy air separation eliminates the need for an expander and utilises the cooling capacity of LNG and isothermal throttling refrigeration. The air separation unit uses circulating nitrogen gas to liquefy into liquid nitrogen in a liquefier, which is fed into the lower tower, where the cold is transferred to the distillation system to pump the dirty liquid nitrogen thr...

Cryogenic air separation nitrogen production uses air as raw material, which is compressed, purified and heat exchanged to liquefy gas air into liquid air. Liquid air is mainly a mixture of liquid oxygen and liquid nitrogen. Liquid oxygen and liquid nitrogen have different boiling points and are separated by distillation to obtain nitrogen. 1. Air compression and purification The air passes through the air strainer to remove dust and mechanical impurities, then enters the air compressor, compresses to the required pressure, and then goes to the air cooler to reduce the air temperature. It then enters the air drying purifier to remove moisture, carbon dioxide, acetylene and other hydrocarbons from the air. 2. Air separation The purified air enters the main heat exchanger in the air separation column, and is cooled to the saturation temperature by the reflux gas (production nitrogen gas, waste gas), and is sent to the bottom of the distillation column. The nitrogen is obtained fr