Principle of nitrogen production of cryogenic air separation

For the pipeline with pressure, the easiest problem in the production process is the leakage at the connection flange. Once leakage is found, do not tighten the bolt under pressure. There are some reasons for the leakage in the process of operation, such as gasket damage, pipeline under thermal stress, etc. At this time, the problem can't be solved only by twisting the bolt, and often screw the Bolt hard because the leakage has not been eliminated until the bolt is broken and the high pressure gas in the pipe sprays out, causing injury accidents. There have been several factories which have suffered from the accident of Bolt fracture caused by the screw bolt with pressure and the casualty of flange plate flying out. Therefore, it is necessary to strictly abide by the regulation that the screw bolts with pressure are not allowed, and it is not allowed to hold fluke mentality and violate the operation regulations in order to seize time and catch up with tasks.

The pressure value measured by the pressure gauge reflects the pressure level, but it is not the actual pressure. According to the working principle of the pressure gauge, the measured pressure is the difference between the actual pressure (absolute pressure) and the surrounding atmospheric pressure. When the actual pressure is higher than the atmospheric pressure, the measured pressure is called surface pressure. Absolute pressure should be equal to surface pressure plus atmospheric pressure: absolute pressure = surface pressure when the actual pressure is lower than the atmospheric pressure, the measured pressure is called vacuum degree, which is also called negative pressure. Absolute pressure is equal to atmospheric pressure reduce vacuum degree: absolute pressure = atmospheric pressure-vacuum degree because the atmospheric pressure is approximately equal to 0.1MPa, when the pressure is relatively high, the surface pressure plus this value is approximately equal to absolute pres...