Air separation plant production standard

At present, there are two types of common condensing evaporators in domestic air separation units, plate fin condensing evaporator and tubular condensing evaporator. Tubular condensing evaporator is divided into three types: long tube, short tube and coil. The long tube and short tube are all in row. The tube is made of red copper and the tube sheet is made of brass. It is generally used in small and medium-sized air separation plants. Coil type is generally used for auxiliary condensing evaporator. Because there is no fixed liquid level in the coil, the heat transfer coefficient is small, so it has been gradually eliminated. The plate fin condenser evaporator is made of all aluminum structure, and the plate unit is arranged in vertical star shape. Its characteristics are compact structure, light weight, small volume and easy to manufacture. It is widely used in large and medium air separation plants. Due to the gradual enlargement of the air separation unit, the heat excha

During the start-up phase, when the liquid volume accumulates in the condensing evaporator, the gas and liquid mixture will pass through the liquid air and liquid nitrogen throttle valves. When the throttle valve begins to close, due to the large opening of the valve, when the amount of gas and liquid mixture from the lower column to the upper column changes little, and the pressure of the lower column does not increase significantly, it means that the temperature difference of the condensing evaporator has not increased. At this time, the condensing evaporator and the surrounding insulation have been cooled to the low temperature required by the liquid accumulation stage. Due to a large amount of cold production and a large amount of gas liquefaction, the liquid evaporation in the condensing evaporator is also increased. The rising steam produced prevents the flow of liquid from the sieve plate hole, and gradually accumulates liquid on the tray, so the liquid level will drop. In ad