Abstract:

According to the leakage of reaction product air cooler in the 1.8 Mt/a continuous catalytic reforming unit of a company after the overhaul, the process flow of reforming reaction system and the operating parameters of air cooler are introduced. The overhaul methods for air cooler tube bundle and the various schemes tried in leakage treatment are described. Without inlet and outlet valves, on-line replacement of air cooler tube bundle is realized. Through the macro inspection of leakage points and the analysis of process media and scale inside tube bundle, it is concluded that the deposition of ammonium chloride during daily operation and the humid environment during overhaul and start-up and shutdown cause the under-deposit corrosion, which eventually leads to the perforation and leakage of tube bundle. Some countermeasures are put forward such as strengthening the monitoring of corrosive elements in raw materials, increasing leakage monitoring and alarm means, optimizing the shutdown and start-up steps, reducing the water content in the system, and enriching the detection, inspection and identification methods for tube bundles, which provide reference for the long-term operation of air cooler tube bundles.

Key words:

continuous catalytic reforming/CCR')">"> continuous catalytic reforming/CCR, reaction product air cooler, ammonium chloride, under-deposit corrosion