Heat exchanger

In the air separation plant, the main heat exchanger is the key equipment to ensure the performance of the whole set of equipment. The function of the main heat exchanger in the molecular sieve pre purification process air separation equipment is to ensure the temperature difference at the hot end to be kept at the design value by recovering the cold quantity of the backflow gas, provide sufficient expander gas to expander, make up for the cold quantity loss of the equipment, and provide the raw gas under the design condition for the lower tower.

The most likely leakage of switching heat exchanger is the welding line, especially the joint of the head and the pipeline. Most of the causes of leakage are the quality problems of manufacture and installation, which are also related to maintenance. The working condition of switching heat exchanger is poor. It is not only impacted by alternating airflow, but also changes greatly in airflow temperature. In long-term operation, the weak parts are easy to leak. Therefore, the welding quality should be strictly guaranteed during manufacture and installation. After installation, strict leak detection and pressure test must be carried out before driving, and problems should be dealt with timely to avoid passivity after driving. There are three methods to check whether the switching heat exchanger leaks in operation: 1) flow method. When a large amount of leakage occurs between the channel of product oxygen or product nitrogen and air channel, the output of oxygen or nitrogen increases ob...