Full liquid air separation process

The purified air enters the fractionator and exchanges heat with the returned polluted nitrogen, oxygen and nitrogen through the main heat exchanger. After cooling, a small part of it is liquefied, and the gas-liquid mixed air is throttled to the pressure of 0.55 MPa. After distillation, 99.999% pure nitrogen is obtained at the top of the lower column, and then it enters the main cooling column, and is condensed into liquid nitrogen by evaporation of liquid oxygen in the upper column. A part of liquid nitrogen is returned to the lower column as reflux liquid, and the remaining liquid nitrogen is throttled after cooling. Enter the sprayer at the top of the upper column. The bottom residue is liquid air containing 38% oxygen. After passing through the liquid air subcooler, it enters the middle of the upper column to participate in distillation. At the same time, the polluted liquid nitrogen flow is drawn out from the middle of the lower column and then enters the upper column as reflux l

There must be enough smooth straight pipe sections before and after the flow orifice plate. The distance is 10 times of pipe diameter in front of the orifice plate and 5 times of the pipe diameter behind the orifice plate, and no factors affecting the measurement accuracy (such as pipe joint, etc.) are allowed. The inner surface of the pipe weld should also be ground smooth, and the gasket should not extend into the inner diameter of the pipe. And carefully check the installation direction of the orifice plate, do not install it in reverse. (judgment method: the small exit is the entrance, and the large exit is the outlet)