Wear of Engine Parts Caused by Catalyst Fines in Heavy Fuel

Abstract

FCC slurry bottom oil and FCC cycle oil are getting used as base stock for making a marine heavy fuel even in Japan. The marine heavy fuel which contains FCC slurry bottom oil and FCC cycle oil contains small quantity of catalyst fines, because it can not be recovered completely by a catalyst reclaimer. The catalyst fines in a fuel oil are very abrasive ones and wear engine parts such as piston rings, a cylinder liner and parts of a fuel injection pump.
But, few data concerned with the relation between catalyst fines and engine wear have been presented, specially the quantitative relations. Therefore, influence of catalyst fines on engine wear has been investigated by the engine tests with the heavy fuels contained known quantities of catalyst fines.
The five kinds of heavy fuels which contain catalyst fines of 0, 30, 60, 100 and 150 ppm, were prepared for the engine tests. The engine test of 30 hour duration was carried out for each fuel.
Main items measured included the wears of piston rings, a cylinder liner, crank-pin metals, a plunger, a barrel, a delivery valve and a needle valve, and Fe and n-pentane insoluble contents in lubricant.
From the test results, the followings are concluded.
1. Piston ring and cylinder liner wears increase in proportion to an increase of catalyst fines content in a fuel oil.
2. In the case of a trunk piston type engine, Fe and n-pentane insoluble contents in lubricant increase in proportion to an increase of catalyst fines content in a fuel oil, and crank pin metal wear increases consequently.