DEAR Air separation plant.The left half of the saturation curve is the saturated liquid line, the right half is the saturated vapor line, and the vertex is called the critical point. The region below the saturation curve is the wet vapor region, and the region is the mixture of gas and liquid, indicating that some of them are liquid.DEAR Air separation plant.Make up pebbles can be added from the pebble make-up port at the upper part of the accumulator without stopping. The filling ports are equipped with sealing devices to prevent air leakage and cooling during filling. Before filling, pebbles should be cleaned to prevent weeds, silt and other debris from entering the accumulator, affecting heat transfer and increasing resistance.DEAR Air separation plant.The liquid air subcooler is blocked and the liquid air quantity is reduced, which makes the temperature of sewage nitrogen low and causes the air liquefaction at the cold end of the switching heat exchanger. When several expanders are running at the same time during the liquid accumulation stage of the start-up process, the cold capacity of the expander is too large, and the liquefier can not be fully recovered, the cold end of the accumulator (or switching heat exchanger) may also have air liquefaction.
The convective heat transfer process of heat transfer from wall 2 to cold fluid (temperature is TF2). The process of heat transfer in inter wall heat exchanger is generally composed of three stages: convection heat conduction convection. For example, in a plate fin heat exchanger, the air first transfers heat to the fins and baffles, and then to the backflow gas to reheat oxygen, pure nitrogen and dirty nitrogen, and the air temperature decreases due to heat release.Safety valve is an automatic valve, its function is to ensure that the machine or equipment will not be damaged due to overpressure. When the working pressure P ≥ 0.6MPa, the take-off pressure of the safety valve should be 1.05 ~ 1.1 times of the working pressure; when the working pressure P < 0.6MPa, it should be 1.2 ~ 1.25 times of the working pressure.DEAR Air separation plant.If there is air leakage, the gas shall be discharged and the pressure shall be increased again after elimination. Stop air intake and check once every 1MPa rise until the maximum allowable working pressure of the equipment is reached. Remove the air inlet pipe connector. Check the high pressure air inlet flange, expander inlet valve, high pressure blow off valve and pressure gauge for air leakage with soapy water.
The crude argon column can only be put into operation when the working condition of the air separation unit is particularly stable and the purity of oxygen and nitrogen meet the requirements. When the argon fraction does not meet the requirements and the nitrogen content is too high, the oxygen supply valve can be turned down and the nitrogen discharge valve can be turned up. At the same time, the oxygen content increases and the argon content decreases.After the fractionator is in place, put through the vertical line, adjust the pad iron to make the verticality of fractionator less than 1 / 1000, and install the foot screw. There are two installation methods of foot screw: one is to use the bottom plate hole of fractionator, the other is to press the bottom plate with pressing plate. And grouting once.Temperature method. When the leakage occurs between the air channel and the polluted nitrogen channel, the temperature in the middle will change obviously, and the leakage unit can be determined from the temperature change. Moreover, the amount of air intake will also increase. Repair welding shall be carried out after identifying the leakage position. If it is an individual channel leakage, the channel can be sealed. When serious leakage cannot be solved, the heat exchanger unit shall be replaced.
