Air separation plant.Overpressure on the upper tower is very dangerous. If it is not handled in time, it will cause explosion on the upper tower. The main reasons for the sudden rise of the pressure in the upper tower of the full low pressure oxygen generator are that the sewage nitrogen switch valve can not be opened and the gas discharge of the upper tower suddenly decreases, or the automatic valve fails and a large amount of positive air flows into the sewage nitrogen channel.Its temperature can be lower than that of the cooled medium (chilled water, etc.), so it can absorb heat Q2 from the cooled medium in evaporator 4, and the refrigerant will evaporate into low-pressure steam and return to the compressor for circulation. Therefore, compared with the refrigeration in the oxygen generator, the common point of the refrigeration in the refrigerator is that the compressor needs to consume work.Air separation plant.The basic method of extracting rare gases is to use their different boiling points and molecular differences. But because their content is very small, they often need to be concentrated step by step and purified in stages, that is, after two stages of rough and refined, so the process is more complex.
Large size gate valves and pneumatic control valves should be installed vertically to avoid deviation due to the heavy weight of the valve core, which will increase the mechanical wear between the valve core and the bushing and cause leakage; when tightening the compression screw, the valve should be slightly open to avoid damaging the top sealing surface of the valve;Air separation plant.At the same time, open the blow off valve on the liquid oxygen side, and use the expansion air and liquid air entering the upper tower to reduce the main cooling temperature. Some equipment adds a branch pipe for main cooling on the liquid nitrogen pipeline. When cooling the main cooler, open the valve 6 to make the cold air flow through the nitrogen channel of the main cooler, and then send it to the expander or as purge gas. After cooling, close valve 6.Air separation plant.It is generally believed that under normal working conditions, the cooling capacity of expander accounts for 85% - 90% of the total cooling capacity, and the cooling capacity of throttling effect accounts for 10% - 15% of the total cooling capacity. When the unit is started up or some liquid products are produced, the refrigeration capacity of the expander will be increased to make up for it, which will account for a larger proportion.
Air separation plant.When the cooling loss of the unit increases, the cooling capacity is insufficient, which reduces the moisture content of the air entering the lower tower. The amount of nitrogen required to condense in the main cooling increases, and the heat load of the main cooling increases. Correspondingly, the evaporation capacity of liquid oxygen increases, and the liquid oxygen level decreases;Under the condition of constant water vapor content, due to the decrease of temperature, the original unsaturated water vapor in the air can become saturated vapor, and the excess water will be separated out. The temperature at which water vapor reaches saturation is called the dew point.Air separation plant.In many practical problems, even if the absolute humidity is the same, due to different temperatures, the corresponding saturation content is also different, that is, the amount of moisture that can be contained in the air is also different. Therefore, the speed of evaporation is different. In order to express the distance of moisture content in air from saturation state, the concept of relative humidity is adopted.
