The strict requirements for pressure and leak testing of air separation units are crucial, mainly due to their multiple impacts on the operational safety, production efficiency, equipment life, and economy of air separation units.
The air separation unit processes low-temperature media such as liquid oxygen and liquid nitrogen. If there is a leak in the pipeline or equipment, direct contact of the low-temperature liquid with air can cause the failure of the pearl sand insulation layer, and the cold box wall may freeze or even crack. Leakage of liquid oxygen in contact with combustible materials may also cause explosions. The cold box uses high-purity nitrogen as the sealing gas. If liquid oxygen leaks, it will cause the oxygen content in the sealing gas to exceed the standard, the pressure to rise abnormally, and even cause dangers such as sandblasting and cold box deformation. Leakage can result in the inability to recover the cooling capacity of low-temperature media, increase cooling loss, and force equipment to compensate for the cooling capacity gap by increasing expansion capacity. If the leakage is not detected in a timely manner, it may cause equipment overpressure, abnormal temperature, and other problems, leading to forced shutdown. Leakage may cause severe fluctuations in pressure and temperature, leading to stress damage to equipment and pipelines and shortening their service life. If the leakage is not detected in a timely manner, it may lead to more serious equipment damage and significantly increase maintenance costs.
Pressure testing and leak detection can ensure effective recovery of low-temperature medium cooling capacity, reduce cooling capacity loss caused by leakage, and improve overall energy efficiency. By reducing cold loss, energy consumption, and maintenance costs, pressure testing and leak detection can significantly reduce the operating costs of air separation units and improve economic benefits.
