Current situation and development trend of analytical refrigerants
Recently, the refrigerant industry has suddenly become hot. The growth of HCFC-22 (R22) in March and April reached about 18% and 12% respectively. The stock prices of related refrigerant listed companies rose and stopped in the middle of May. Enterprises producing R22 and other products started to realize full load.
Refrigerant is also known as refrigeration working medium, which is commonly known as snow seed in some areas of the south. It is the working substance that circulates continuously in the refrigeration system and realizes refrigeration through its own state change. The phase change of refrigerant is used to transfer heat. The refrigerant absorbs the heat of the cooling medium (water or air, etc.) in the evaporator and vaporizes. In the condenser, the heat is transferred to the surrounding air or water and condenses. At present, there are more than 80 kinds of substances that can be used as refrigerants, the most commonly used are ammonia, freon, water and a few hydrocarbons.
Refrigerant classification and use
There are several kinds according to the composition.
1. Single refrigerant
2. Mix the refrigerant. (Note: a single refrigerant contains only one chemical substance, and its thermophysical performance parameters are constant. For example, R134a, R152a and other refrigerants have high energy efficiency. A mixed refrigerant is a mixture of two or more refrigerants.)
The detailed classification is as follows:
(1) Inorganic compounds. Water, ammonia, carbon dioxide, etc.
(2) A derivative of saturated hydrocarbons, commonly known as Freon. Mainly derivatives of methane and ethane. Such as R12, R22, R134a, etc.
(3) Saturated with hydrocarbons. Such as propane, isobutane, etc
(4) Unsaturated hydrocarbons. Such as ethylene, propylene, etc.
(5) Azeotropic refrigerant mixture. Such as R502.
(6) Non azeotropic refrigerant mixture. Such as R407C, r410, etc.
Usually according to the standard evaporation temperature of refrigerant, it can be divided into three cateries: high, medium and low temperature. Standard evaporation temperature refers to the evaporation temperature under standard atmospheric pressure, that is, boiling point.
(1) High temperature (low pressure): Standard evaporation temperature (TS) > 0 ℃, condensation pressure (PC) ≤ 0.2-0.3mpa, common R123, etc.
(2) Medium temperature (medium pressure): 0 ℃ > TS > - 60 ℃, 0.3MPa < PC < 2.0MPa, commonly used ammonia, R12, R22, R134a, propane, etc.
(3) Low temperature (high pressure): TS ＜ - 60 ℃, commonly used R13, ethylene, R744 (CO2), etc.