The pressure change of the lower tower is related to the following factors:
1) if the air and liquid nitrogen throttle are opened too big, the pressure of the lower tower will drop; if the closing is small, the pressure of the lower tower will rise (but the normal range is not obvious );
2) the enthalpy value of the air entering the tower decreases, and the pressure of the lower tower decreases (because of the increase of moisture content, the vapour decreases. If it is too cold, the high pressure and medium pressure will decrease significantly ). If the air enthalpy increases, the pressure of the lower tower will increase;
3) when the liquid oxygen level in the condensing evaporator is too low, the heat transfer surface appears to be insufficient. In order to ensure the condensation of nitrogen vapor in the lower tower, the temperature difference of heat transfer will be enlarged, which will lead to the rise of pressure in the lower tower;
4) neon-helium gas accumulates in the condenser, which affects the heat transfer effect and makes the pressure of the lower tower rise;
5) when the processing air volume increases, the heat load of the condensing evaporator increases and the pressure of the lower tower rises;
6) when the tower plate is dirty or its pores are blocked by solid carbon dioxide and ice flowers at the end of the cycle, the resistance of steam rising will increase, which will lead to the rise of pressure in the lower tower. This situation is easy to cause liquid suspension. When the resistance increases to a certain extent, the pressure of the lower tower fluctuates periodically, and the fluctuation becomes more and more frequent. As a result, the resistance, purity, liquid level and other parameters fluctuate, which indicates that the air separation Tower has produced liquid suspension and needs to be stopped and heated;
7) when the liquid throttle is blocked, the main cold liquid oxygen level will drop, and the liquid level will rise. If it is not handled in time, the liquid level will be too full, and the lower tower pressure gauge needle will shake, leading to the rise of the lower tower pressure;
8) when the high pressure throttle or the Cam switch of the expansion machine is on, the pressure of the lower tower will fluctuate temporarily;
9) when the opening height of the inlet and outlet valves of the expansion machine is not enough, the pressure of the lower tower will drop; when the closing is slow or not strict, the pressure of the lower tower will rise;
10) when the opening of the high pressure throttle is too small or blocked, the pressure of the lower tower will drop;
11) the pressure of the lower tower is related to the purity of liquid oxygen and nitrogen (the top of the lower tower. The higher the purity of liquid oxygen is, the higher the purity of nitrogen on the top of the lower tower is, and the higher the pressure of the lower tower is; otherwise, the lower the pressure is;
12) the pressure of the lower tower will rise and fall as the pressure of the upper tower rises and falls.
