METHOD FOR HARDENING CATALYST GAS FLOW-IN END PART

摘要

PROBLEM TO BE SOLVED: To provide a method for hardening a catalyst gas flow-in end part by which a coating layer having a proper thickness can uniformly be formed even without plentiful experience or high technique. SOLUTION: A ceramic having higher hardness than that of the catalyst is applied on the gas flow-in end part of the plate like or honeycomb like catalyst. The gas flow-in end part of the catalyst is drawn down at the rate of 0.01-1 mm/sec to be dipped into coating slurry and drawn up at the rate of 0.01-1 mm/sec from the slurry. The coating slurry is a water based slurry consisting essentially of silica and/or alumina and it is preferable that a 1st layer is formed on the whole range of 30-70 mm from the gas flow-in end part and a 2nd layer is formed on the surface ranging from the gas flow-in end part to 10-20 mm. Any of the 1st layer and the 2nd layer can be previously formed.