DEAR Liquid air separation unit.Open the small cover plate of the top cover of the fractionator and fill it with pearlite; install the safety valve (the starting and tripping pressure should be checked in advance), thermometer, liquid level gauge, flowmeter and other accessories; install the connecting pipeline and accessories of the heating furnace and fractionator, and check the air tightness of 0.5MPa.In chemical industry, in the process of chemical fertilizer production from synthetic ammonia, in addition to nitrogen as the main feed gas, oxygen is used in high temperature cracking of heavy oil, gasification of pulverized coal and other processes to strengthen the process and increase the output of chemical fertilizer. Generally, a 100000 t / a ammonia plant needs to be equipped with a 10000 m3 / h oxygen generator. In addition, a large amount of oxygen is consumed in the production of methanol, ethylene and propylene from natural gas reforming, oxidation, desulfurization and recovery. When the oxygen consumption per ton of product is in the range of 300-1000m3 / T, 10000-30000m3 / h oxygen generator should be equipped.
DEAR Liquid air separation unit.At this time, because the temperature of the positive flow air into the main heat exchanger also increases, the maximum reheating temperature of the low-temperature and low-pressure gas in the backflow can be equal to the inlet air temperature T ′ 2, that is, t ′ 4 = t ′ 2. Accordingly, the enthalpy is h ′ 4.DEAR Liquid air separation unit.The air tightness test of fractionator has been done before leaving factory, but the equipment may be damaged due to vibration during transportation. Therefore, air tightness should be checked again before installation. In addition, if severe frosting is found on the shell of the air separation tower after operation, or after overhaul, air tightness inspection is also required.The extraction rate of oxygen in the process air is further reduced, and the output of oxygen is reduced. Therefore, for 1000m3 / h air separation plant, it is not suitable to extract some liquid products. For a 50m3 / h small medium pressure air separation plant, if 4 L liquid nitrogen is extracted per hour, the air pressure should be increased by 0.3-0.4 MPa.
DEAR Liquid air separation unit.For medium pressure air separation unit, it is composed of expansion air and air which is throttled and depressurized by throttle-1 valve after leaving heat exchanger. Under normal conditions, their comprehensive state into the tower has a certain "moisture content" (liquefaction rate). The air condition into the tower is guaranteed by the heat exchange system and the cooling system in the air separation unit.If two expanders operate at the same time, the total expansion capacity is 3500m3 / h due to throttling in front of the expander, and the parameters before the expander are P1 = 0.50mpa, T1 = 113k; the parameters after the expander are P2 = 0.125mpa, T1 = 83k, then the unit cooling capacity is ah = h1-h2 = 7955 (kJ / KMOL) - 7200 (kJ / KMOL) = 755kj / KMOL.DEAR Liquid air separation unit.The oxygen content in nitrogen should be reduced in the adjustment. Extend the continuous operation cycle of the equipment, reduce the downtime maintenance time. Therefore, it is necessary to strengthen the daily maintenance of the equipment and overhaul the equipment regularly. To ensure the removal effect of water and carbon dioxide. Absolutely avoid the leakage of low temperature liquid and gas in the tower. When heating the single equipment, the temperature should not be too high.
