First of all, the steam pressure and flow rate required for the molecular sieve heating should meet the requirements of process design. Heating regeneration process can be judged by regeneration temperature curve. Pressure relief stage: due to the decrease of pressure, the adsorption capacity of molecular sieve decreases, and the water and carbon dioxide molecules that were originally adsorbed are partially desorbed, resulting in the decrease of temperature.DEAR Air separation plant.The temperature difference between nitrogen and air is increased from 4 ℃ to 6.5 ℃ and the temperature difference between oxygen and air is increased from 5 ℃ to 18.5 ℃ because the temperature of air entering the device is increased from 30U to 51.5 ℃. At this time, we should check the cause of air temperature rise into the tower and eliminate it.In terms of manufacturing process, limited by the size of salt bath furnace, the maximum length of plate unit can only be 2.1m, and the section size is 750mm × 700mm ~ 1100mm × 1000mm. At present, with the development of technology, the longest plate unit can be 6m long.
According to the maximum cooling capacity and the cooling capacity required for cooling and liquid accumulation, the start-up time of the unit also needs to be more than 36 hours. Large air separation units are generally equipped with liquid oxygen storage tanks as emergency standby oxygen. If necessary, it is theoretically possible to fill the tower with liquid oxygen to shorten the start-up time of the air separation unit.DEAR Air separation plant.The temperature difference between the air inlet and the reflux outlet of the fractionator is measured by thermometers. The difference between the inlet air temperature and the outlet reflux air temperature is called "hot end temperature difference", which is one of the important bases for operation. Glass thermometer is often used to measure the temperature of small air separation unit. If the thermometer is not installed correctly and the indication value is not accurate, it may cause misoperation.DEAR Air separation plant.The liquid level should be stable. The stability of liquid oxygen level indicates the balance of cooling capacity of the equipment. If the liquid oxygen level changes from high to low, it is very difficult to adjust the purity. The expansion volume and the opening of liquid air and liquid oxygen control valves should be adjusted reasonably to make the liquid oxygen surface stable.
In general, it will not exceed the allowed air volume of the upper tower, so it is not necessary to pump dirty liquid nitrogen to directly increase the reflux ratio of the distillation section. The extraction port, pipeline and valve are reduced, and the process is simplified. Generally, the lower tower of oxygen generator with large output of pure gas nitrogen product does not pump liquid nitrogen.When the pressure exceeds the specified value, the valve will open automatically, and the valve will close automatically when the pressure is restored by removing part of the gas. Before installation, the safety valve should be debugged according to the usage before installation. The safety valve is generally calibrated at least once a year. The safety valve should be adjusted on the system, and should not leak under the working pressure, and then be lead sealed.Due to the large amount of molecular sieve, the molecular sieves produced by different kilns are different. Therefore, the molecular sieves from the same batch of kilns should be evenly filled into two molecular sieve tanks. After the completion of filling, use the flattening mechanism to flatten, and check whether the molecular sieve filling reaches the standard height (the ring chamber has been buried under the molecular sieve). The molecular sieve is leveled again until the molecular sieve on the sieve bed is smooth and there is no concave convex problem. If there is no problem, it can be considered that the filling work is finished.
