The working pressure of the full low pressure air separation unit is about 0.6MPa, so the refrigeration capacity of throttling effect is very small. For each cubic meter of process air, it is only 1.36kj/m3. For each cubic meter of process air, the cooling loss of the unit is 4.2-7.5kj/m3, and the incomplete heat exchange loss is about 3.9kj/m3 when the temperature difference at the hot end is 3 ℃.In addition to oxygen, nitrogen and argon, the air also contains a very small amount of rare gases such as neon, helium, krypton and xenon. According to the volume fraction, neon accounts for about 15 × 10-6 ~ 18 × 10-6, helium accounts for 4.6 × 10-6 ~ 5.3 × 10-6. Krypton is only 1.08 × 10-6, xenon is 0.08 × 10-6, commonly known as "gold gas". Because of their small content and complex extraction process, only when the capacity of the oxygen generator is more than 10000 m3 / h can the extraction device be considered.DEAR Cryogenic air separation unit.In order to liquefy the air, it is necessary to cool the air to a temperature below 100k, which is called deep freezing; and the process of separating liquid from air by using boiling point difference is called distillation process. Low temperature air separation is the combination of cryogenic and distillation, which is the most widely used air separation method at present.
The size of temperature change is also related to the amount of material (flow). The same amount of heat, more material, the temperature change is small. The product of specific heat capacity C and quantity m is called "heat capacity". In the intercooler, the heat Q1 released by the air is equal to the heat Q2 absorbed by the cooling water.DEAR Cryogenic air separation unit.When the pressure exceeds the specified value, the valve will open automatically, and the valve will close automatically when the pressure is restored by removing part of the gas. Before installation, the safety valve should be debugged according to the usage before installation. The safety valve is generally calibrated at least once a year. The safety valve should be adjusted on the system, and should not leak under the working pressure, and then be lead sealed.DEAR Cryogenic air separation unit.First of all, the steam pressure and flow rate required for the molecular sieve heating should meet the requirements of process design. Heating regeneration process can be judged by regeneration temperature curve. Pressure relief stage: due to the decrease of pressure, the adsorption capacity of molecular sieve decreases, and the water and carbon dioxide molecules that were originally adsorbed are partially desorbed, resulting in the decrease of temperature.
In the production of rare gases krypton and xenon, with the concentration of krypton and xenon, N2O is also concentrated. The content of N2O can reach 100 × 10-6 ~ 150 × 10-6. N2O itself does not burn, but can decompose. This will affect the removal of CH4 from crude krypton and xenon and the adsorption of water and carbon dioxide by molecular sieve.The mass of different gases is different, 1.429kg for oxygen, 1.25Kg for nitrogen and 1.293kg for air. However, for different gases, when their mass is equal to their molecular relative mass, they all have the same standard volume. That is to say, 32kg oxygen, 28KG nitrogen, 39.95kg argon and other gases account for 22.4m3 of the standard volume.The bubbles of liquid in the cavity grow up rapidly, break away, penetrate the surface and finally break. The bubble core grows up in the cavity and becomes the core of the next bubble. In this way, with the help of surface tension, the liquid continuously enters the cavity and evaporates in the cavity.
