Heat exchange equipment is an essential equipment to achieve air liquefaction, separation and maintain the normal operation of the device. Moreover, whether the heat exchanger works normally or not directly affects the economy of the air separation unit. Although there are many types of heat exchangers in air separation plant, they can be divided into three types according to their heat transfer principles: 1) inter wall type. 2) Regenerative. 3) Hybrid.DEAR Biogas purification unit.In the cold state, the deformation and leakage of each part should be checked in detail. The location of the leakage point can be judged according to the frosting condition, and should be marked. After freezing, the flange screws should be tightened again to make up for the screw relaxation caused by different thermal expansion coefficient at low temperature. However, attention should also be paid not to screw too tightly to prevent excessive prestress.The working temperature range of molecular sieve is generally 8 ~ 15 ℃, which can work normally. Once beyond this range, the loading capacity will increase, the adsorption effect will decrease, and even the adsorption effect will lose. When the chiller fails, the temperature of the air entering the molecular sieve adsorber increases.
The liquid gasification filling system consists of liquid storage tank, liquid pump and gasifier. In order to ensure the normal operation of the liquid pump, in addition to the reliability of the pump structure, piping technology is also very critical. Improper piping will cause "cavitation" of the liquid pump, reduce the flow rate and increase the mechanical loss of the pump; otherwise, due to the serious gasification of the liquid in the pipe, the filling pressure can not be increased and the pump can not work normally.From the point of view of heat transfer, the heat transfer capacity of the heat exchanger will be affected by the heat transfer capacity of the tube wall (or plate wall). The thermal conductivity of a material is expressed by thermal conductivity. It refers to the amount of heat (J) transferred through unit area (M2) in unit time (s) when the wall thickness is 1m and the temperature difference is 1 ℃. The unit is w / (m ·℃).In energy industry, in order to maintain the temperature of oxidation layer in the furnace, enough oxygen must be supplied during coal pressurized gasification. The purity of oxygen is not less than 95%, and the oxygen consumption per kilogram of coal varies with the type and quality of coal. It is 0.14-0.18m3/kg for lignite and 0.17-0.22m3/kg for bituminous coal. The oxygen pressure is determined by the production process requirements. The higher the pressure, the less oxygen consumption. For the IGCC unit, the oxygen demand of 1kW is about 5.6m.
In practical work, kerosene or soapy water can be used for leak detection. First, install the automatic valve in a special tool, put in 0.6MPa pressure and stop pressure for 3min. The standard of air leakage is: no more than 6 soap bubbles with diameter of 40mm can be blown out within 3min. The automatic valve qualified by pressure test shall be equipped with split pin for standby. Special attention must be paid to the split pin must be made of low temperature resistant brass or stainless steel products, and can not be replaced by general split pin.Flange connection is to fix two pipes, pipe fittings or equipment on one flange respectively, and then add flange gasket between the two flanges and fasten them together with bolts to complete the connection. Some pipe fittings and equipment have their own flange, which also belongs to flange connection. The flange is divided into threaded connection (threaded connection) flange and welding flange.DEAR Biogas purification unit.Most of the liquid flows down as reflux, and a small part is drawn out from the top as semi-finished product. The liquid with high oxygen content at the bottom of the crude argon column returns to the same tray at the distillation outlet of the main column, or 1-2 trays below the distillation outlet.
