DEAR Air separation equipment.The long tube condensing evaporator is evaporation inside the tube and condensation outside the tube. Its boiling intensity and condensation intensity are related to the geometric size of the tube. The experimental results show that when the unit heat load Q (heat transfer per unit area and time) is constant, the larger the ratio L / Di of tube length L to tube inner diameter Di, the stronger the boiling heat release.The gas in the channel does not switch, so a higher flow rate can be adopted in the design to improve the heat transfer coefficient, and the heat transfer temperature difference of the cross section is not limited by the self cleaning condition. In order to reduce the loss of incomplete recovery of cooling capacity at the hot end, the temperature difference at the hot end is still small (2 ~ 3 ℃).DEAR Air separation equipment.Pearlite has good fluidity, and its density is lower than that of water. If people fall into the pearlite layer, they will be drowned and suffocated. Therefore, the manhole on the top of the cold box and the loading position should all be installed with a square grid shaped safety iron grid welded with 8-10mm steel bars to prevent accidents.
DEAR Air separation equipment.At the beginning of pumping, the main thing is to master the speed of pumping. If the air extraction speed is too slow and the air extraction volume is too small, the temperature in the middle of the accumulator will not drop for a long time, and the temperature difference at the cold end is large, which is not conducive to the establishment of the self cleaning condition of the accumulator; if the air extraction speed is too fast, the temperature of the CO2 adsorber will rise, and the temperature in front of the unit will rise, resulting in the temperature rise at the cold end.Discharge non condensable gas. When the air is liquefied in the liquefier, neon and helium with low boiling point will not condense in the liquefier, which will gradually accumulate and occupy part of the heat transfer area, affecting the heat transfer effect, so they should be discharged in time.The heat transfer coefficient K increases with the increase of fluid velocity. However, increasing the flow rate will increase the flow resistance and increase the energy consumption of conveying fluid, so we can not unilaterally emphasize increasing the flow rate. The strength of heat conduction through the wall is not only related to the material and thickness of the wall, but also related to the pollution of the wall.
If the air is compressed to 0.6MPa and the temperature is still 30 ℃, the saturated moisture content in each cubic meter of air is still 30.3g/m3. However, when the pressure increases, the air quality contained in each cubic meter of air increases, and the moisture content increases accordingly. When the temperature is constant and the saturation content is constant, the excess water will precipitate in liquid state.For the plate fin heat exchanger with separate cold section and hot section, the hot section is usually arranged at the top and the cold section is at the bottom; for the plate fin heat exchanger with integral cold section and hot section, the hot section is arranged at the top and the cold section is arranged at the bottom. The advantage of this arrangement is that the pipe from the air passing through the cold end to the lower tower can be shorter and the resistance is smaller.In the actual operation, the situation is much more complicated than the design situation. The main factors affecting the operation cycle include the continuous working ability of the oxygen generator equipment and operating machinery, the quality of heating and blowing before starting, the level of operation in the starting stage and normal operation, the size of air load, etc.
