Abstract: The scaling of flue gas turbine in fluid catalytic cracking unit (FCCU) causes the high failure rate of the turbine. The wear of catalyst particle was confirmed by analyzing the chemical composition of powder, fouling materials and catalyst in the trouble machine in a petrochemical corporation. It is found that the densification of deposited fine powder is a sintering process, proved by measuring the specific surface areas and pore volumes of the fresh catalyst, equilibrium catalysts and powder. It is the powder deposition and subsequent sintering that leads to the failure of the flue gas turbine.ine.