To prevent corrosion of carbon steel in the heat exchanger, two measures have also been taken: first, the material of the central tubes of the two molecular sieve purifiers has been changed from carbon steel to stainless steel; The second is to replace the carbon steel structure of the expansion cooler with a stainless steel structure to ensure the safe and long-term operation of the air separation unit.

To avoid further blockage faults in the main heat exchanger, the following measures can be taken:

1) Increase monitoring points. During the renovation of the air separation unit, temperature measurement points were added to the inlet and outlet pipelines of each channel in each plate unit of the main heat exchanger in the horizontal screw centrifuge.

2) Clean the main heat exchanger. Clean the main heat exchanger and add auxiliary heat exchanger units.

3) Strengthen on-site maintenance and construction management. Require full process control of maintenance. Before loading and unloading molecular sieves, blind plates must be installed at the flange on the central tube. And adopt a dedicated person responsible and focused supervision approach, strictly implement the equipment maintenance and acceptance procedures, and strictly control the quality of maintenance. Further improve the process treatment steps after maintenance. Fully evaluate the potential hazards and hidden dangers that the maintenance process may cause to the equipment, and develop corresponding emergency plans to minimize the possibility of malfunctions.