When the purity of liquid oxygen is constant, the evaporation temperature increases with the increase of pressure. For example, when the purity of liquid oxygen is 99.55%, if the absolute pressure increases from 0.14MPa to 0.15Mpa, the evaporation temperature will increase from 93.5k to 94.25k. For the condensation process of gas nitrogen, when the pressure is constant, the purity of gas nitrogen increases, and the condensation temperature decreases.The installation of stop valve should make the medium flow direction consistent with the arrow marked on the valve body, so that when the valve is closed, the pressure is applied on the cone at the top of the valve, and the packing is not loaded. However, for valves that are not frequently opened and closed but need to be strictly guaranteed not to leak in the closed state (such as heating valves), they can be consciously reversed to make them tightly closed with the help of medium pressure;DEAR Air separation unit.Because of the low concentration of oxygen in the liquid air, the purity of oxygen will decrease and the yield of oxygen will decrease. Therefore, the best distillation condition of the lower column is to increase the amount of liquid nitrogen as much as possible when the purity of liquid nitrogen meets the requirements. On the one hand, more reflux is provided for the upper column distillation section;
If the temperature is increased by 1 ℃, the energy consumption of the air separation unit will increase by about 2%. Lowering the inlet air temperature can not only improve the economy of the air separation plant, but also reduce the saturated moisture content in the air. For example, when the absolute pressure of air is 0.6MPa and the air temperature drops from 40 ℃ to 30 ℃, the saturated moisture content in every 1kg of air will be reduced by about 40%.DEAR Air separation unit.In this way, continuous refrigeration can be realized. In the oxygen generator, it is also a refrigeration process to reduce the air temperature to the liquefying temperature. Therefore, there must be a compressor at the cost of power consumption. Only in the oxygen generator, air is used as the working medium, and the purpose of cooling is achieved by first compressing and then expanding the air. Then cool the air itself until it reaches the liquefying temperature.Low pressure small diameter has threaded flange, high pressure and low pressure large diameter are welded flange, different pressure flange thickness and connecting bolt diameter and quantity are different. According to different levels of pressure, flange gasket also has different materials, from low pressure asbestos gasket, high pressure asbestos gasket to metal gasket.
In the condensing evaporator, the liquid oxygen from the bottom of the upper tower is heated and evaporated by the gas nitrogen from the top of the lower tower, part of which is extracted as oxygen product, and part of which is used as rising gas to participate in the distillation of the upper tower; the gas nitrogen releases heat and condenses into liquid nitrogen, part of which is used as reflux to participate in the distillation of the lower tower, and part of which is throttled to participate in the distillation of the upper tower. This shows that the temperature of gas nitrogen is higher than that of liquid oxygen in condensing evaporator.No matter what kind of heating method, we should pay attention to the temperature curve changes of heating and cold blowing in the regeneration process of adsorber. The abnormal change of temperature curve indicates that the regenerative heat source (steam or electricity) is insufficient or the gas volume is insufficient; the reason for the change of adsorber load (especially adsorption water volume) should be found out.
