It has been widely used in large and medium air separation plants. The plate unit is generally arranged in a vertical star shape. Because the height of plate unit is limited by safety, the heat exchange area that can be arranged in the range of tower diameter is limited, and the double-layer or multi-layer (four layer) star arrangement is used in large air separation units.DEAR Air separation equipment.The valve should be positioned before pipeline installation. The piping shall be natural and cannot be pulled hard in the wrong position to avoid prestress; the opening and closing test of low-temperature valve shall be conducted in cold state (such as in liquid nitrogen) as far as possible before positioning, and the valve shall be flexible without jamming;DEAR Air separation equipment.At the beginning of pumping, the main thing is to master the speed of pumping. If the air extraction speed is too slow and the air extraction volume is too small, the temperature in the middle of the accumulator will not drop for a long time, and the temperature difference at the cold end is large, which is not conducive to the establishment of the self cleaning condition of the accumulator; if the air extraction speed is too fast, the temperature of the CO2 adsorber will rise, and the temperature in front of the unit will rise, resulting in the temperature rise at the cold end.
Overpressure on the upper tower is very dangerous. If it is not handled in time, it will cause explosion on the upper tower. The main reasons for the sudden rise of the pressure in the upper tower of the full low pressure oxygen generator are that the sewage nitrogen switch valve can not be opened and the gas discharge of the upper tower suddenly decreases, or the automatic valve fails and a large amount of positive air flows into the sewage nitrogen channel.There is also a process of understanding and practice whether the plate unit of plate fin condensing evaporator adopts full immersion operation. When the plate fin condensing evaporator was introduced from abroad, the liquid oxygen surface impregnation rate was about 70%. Of course, this can meet the requirements of heat transfer without affecting the distillation conditions.DEAR Air separation equipment.The typical adsorption temperature of Molecular Sieve Purifier generally, as long as the air precooling system is normal, the temperature of air entering the purifier will not change, and the temperature curve is basically a horizontal straight line. The temperature of the air out of the adsorber is slightly higher than the inlet temperature due to the influence of adsorption heat release, and it is approximately a straight line most of the time.
DEAR Air separation equipment.If the temperature difference at the hot end of each backflow gas is equal, the sum of their air volume is equal to the positive flow air volume. When the temperature difference at the hot end increases by 1 ℃, the incomplete heat exchange loss will increase by 1.31kj/m3, which will increase the total cooling loss by more than 10%. Therefore, it is of great significance to reduce the total cooling loss of the device by reducing the temperature difference at the hot end as much as possible. Especially when it is found that the temperature difference at the hot end is larger than the specified value, we should pay attention to find out the reasons and take corresponding measures.If circulation is not used, the temperature in front of expander will be - 150 ℃, and the temperature in back of expander will be below - 185 ℃, so liquid may be produced in expander. Therefore, circulation must be used before the cold end reaches - 150 ℃.With a large amount of oxygen condensing, the oxygen content in gas phase decreases, and the argon condensing relatively increases. Therefore, the argon content in gas phase gradually decreases, and it is only 0.0% after reaching the top of the tower. Because oxygen and argon are difficult to volatilize to nitrogen, they condense into liquid phase more than nitrogen, so the concentration of oxygen and argon in liquid phase is higher than that in gas phase.
