There is a certain relationship between thermal state parameters, and different for different substances. This relationship reflects its thermal properties. Usually, if any two independent state parameters are known, the value of other parameters can be determined. For example, enthalpy h, entropy 5, etc. can be determined according to temperature Ding and pressure P. The air separation equipment manufacturer should improve the pressure of the upper tower during the process of liquid accumulation. When the equipment cools to the liquefaction temperature, liquid begins to appear. The latent heat of condensation decreases because the liquefaction temperature increases with the increase of pressure. Therefore, in the stage of liquid accumulation, the pressure of the upper tower is increased from 0.04MPa to 0.065mpa, and the liquefaction temperature of oxygen can be increased from -180 ℃ to -178.3 ℃. It can accelerate the liquefaction speed;
The foundation of the tank shall be more than 1m higher than the center of the liquid oxygen pump to ensure that the pump inlet has a high static pressure (higher than the saturation pressure corresponding to the temperature); Minimize the length of the pipe from the tank to the pump inlet to reduce the pressure drop due to flow resistance. A section of bellows and filter is installed at the inlet of the pump; Strengthen the heat preservation of the inlet pipeline to reduce the temperature rise caused by the external heat transfer; The valve of air separation equipment manufacturer shall be positioned before the pipeline installation. The piping should be natural, and the position should not be pulled hard to avoid leaving prestress; Before positioning, the low temperature valve should be opened and closed in cold state (such as in liquid nitrogen), and it is required to be flexible without shell jam;
If the outlet temperature of the purifier rises suddenly during the use, it means that the air has brought the water in the air cooling tower into the adsorber, and it should be treated urgently. At the beginning of the switch, there is a large temperature difference between the inlet and the outlet, even up to 20 ℃. This is because the process of the adsorber is a step-up process during the process of switching to charging, and the adsorption capacity of the molecular sieve increases. Air separation equipment manufacturers can see that the cold quantity is only a special term for a certain heat. This heat absorption ability is obtained at a cost, and it is more precious. In quantity, it is equal to the heat taken from the low-temperature object during refrigeration, and also the heat absorbed by the low-temperature object (all based on the ambient temperature).
In pipe test of heat exchanger of air separation equipment manufacturer. Close the high pressure air throttle valve and the high pressure air inlet valve of expander, install the high pressure gauge and open the valve. Open one blow off valve of lower tower and upper tower, and air source is introduced from blow-2 valve. Open valve 1 to check whether there is air discharge, and then close. When the pressure of heat exchanger rises to 1MPa, pause the air intake and check whether there is air leakage at the external connection. It is also an effective way to shorten the start time by using external cold source. When the main cooling is over, liquid oxygen, liquid air or liquid nitrogen are input from the outside when liquid appears. The infusion method is to connect the liquid source with the liquid oxygen discharge valve, open the liquid oxygen discharge valve, and inject the external liquid into the main cooling.
Before the liquid level of main cooling occurs, the air separation equipment manufacturer first paves a layer of liquid on each tower plate from liquid air feed port to main cooling, and there is rising steam which is constantly generated through the liquid layer on each tower plate. The resistance of the steam through the tray can be reflected from the lower resistance meter. In the start-up stage, when the upper tower lower resistance meter has been indicated, it can be estimated that the liquid oxygen surface will appear. This kind of liquid with temperature lower than saturation temperature is called "supercooled liquid"; The temperature lower than the saturation temperature is called "supercooling". Generally, the liquid has a supercooling degree of 6-7 ℃ after passing the subcooler, and the energy (enthalpy H1) of the corresponding liquid decreases.
