Ultra-low discharge pressure

Special pressure-bearing equipment generally bears internal pressure, that will cause tensile stress inside the shell, which is called working stress. The working stress is directly proportional to the pressure and diameter, and inversely proportional to the vessel wall thickness. The axial stress is half of the circumferential stress. Therefore, for cylindrical vessels, the stress of longitudinal weld is twice that of girth weld. Because the geometric shape of the spherical shell is symmetrical to the spherical center, and the axial stress is equal to the circumferential stress in numerical value. Therefore, the wall thickness of the spherical vessel can be reduced by half as much as that of the cylindrical vessel under the same pressure and diameter.

The load regulation range of low pressure air separation unit is related to the regulating performance of feed air compressor, the regulating performance of expander and the structural characteristics of distillation column. At present, the flow regulation range of turbine air compressor with inlet guide vane is 75% to 100%, and that of turbocharged expander with adjustable nozzle is 65% to 100%. Next, the most important thing is to adjust the residual of the distillation column. At present, the load regulation range of distillation column with structured packing can reach 50% - 100%, while that of traditional sieve tray column is 70% - 100%. If the load is too low, it will cause liquid leakage because the speed of steam passing through the sieve is too slow. When oxygen is sufficient and the oxygen output needs to be reduced, first reduce the output of oxygen products, then reduce the air flow accordingly, and adjust the expansion air volume according to the main cooling level. The