After long-term operation, the air separation unit may produce deposits such as ice, dry ice, hydrocarbons, etc. in the low-temperature vessels and pipelines of the fractionation tower system, resulting in gradually increasing resistance and energy consumption of the unit, which affects the purity and yield of the products. Therefore, after each cycle of operation of the device, the fractionation tower system should generally undergo comprehensive heating and thawing to remove these sediments.
If the resistance of the heat exchanger and distillation tower increases or the inlet pressure of the turbine expander decreases sharply during the operation of the device, the fractionation should be heated and thawed in advance, or the turbine expander should be locally heated. This situation is often related to improper operation and maintenance. The heating gas source of the device is room temperature dry air purified by a molecular sieve purifier. The heating principle is from top to bottom and from inside to outside, trying to achieve a slow and uniform temperature rise in all parts of the device, avoiding large temperature differences caused by rapid temperature rise, which can lead to large thermal stress and damage to equipment or pipelines. When heating, all instrument detection pipelines must also be heated and blown off simultaneously.
Daily maintenance and preventive measures, such as improving filtration systems and controlling water inflow, are also key to reducing sediment formation, effectively extending the lifespan of air separation equipment, improving fractionation efficiency, and reducing safety risks and environmental pressures.
