Classification of the safest refrigeration process

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Classification of safe refrigeration process in chemical industry

I. classification according to refrigeration process

(1) vapor compression refrigeration is referred to as compression refrigeration for short. At present, the most widely used refrigeration is vapor compression refrigeration. It uses the compressor to do work, compress, cool and condense the gas phase working medium into liquid phase, and then make it expand and vaporize (evaporate) under reduced pressure. It takes heat from the low-temperature heat source and reaches the high-temperature heat source. The fatigue life prediction of the rubber damping products has the methods of virtual analysis and fatigue experiment. This process is similar to using a pump to transfer fluid from low to high, so it is sometimes called a heat pump, as shown in Figure 163

(2) absorption refrigeration uses some kind of absorbent to absorb the refrigerant vapor generated from the evaporator, and then uses the heated type of machine to test the mechanical properties of plastics. It is the preferred method to desorb under the pressure of the condenser. That is, the refrigerant vapor is taken out of the low-pressure evaporator and sent to the high-pressure condenser by the absorption and desorption of the absorbent. The absorption system is used to replace the compressor, and the thermal energy is used to replace the mechanical energy for refrigeration operation

common absorption refrigeration systems in industrial production include: ammonia water system, which has been used in practice. Ammonia is used as refrigerant and water as absorbent in the production of synthetic ammonia to separate ammonia from the condensation of mixed gas; Water lithium bromide solution system, which uses water as refrigerant and lithium bromide solution as absorbent, has been widely used in air conditioning technology

(3) steam injection refrigeration uses high-pressure steam injection to create a vacuum, so that the performance characteristics of the gas spring performance tester and the operating environment of the refrigerant under low pressure evaporate and absorb the heat of the cooled material to achieve the purpose of refrigeration. The higher the vacuum, the lower the refrigeration temperature, but not lower than 0 C. Because the latent heat of vaporization of water is large and non-toxic, it is easy to obtain, but its evaporation temperature is high. In industrial production, it is often used to produce frozen water above 0 ℃ or as the cold source of air conditioning

II. Classification by refrigeration degree

(1) the temperature range of ordinary refrigeration is within 173k

(2) the refrigeration temperature range of deep refrigeration is below 173k. Theoretically, all gases can be liquefied as long as they are cooled below the critical temperature. Therefore, deep refrigeration technology can also be called gas liquefaction technology. In industrial production, cryogenic technology is used to effectively separate nitrogen, oxygen, argon, neon and other rare components in the air, and successfully separate methane, ethylene, propane, propylene and other gases in petroleum cracking gas. Cryogenic technology is also widely used in modern medicine and other high-tech fields

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