Severe hydrotreating of diesel can cause fuel-injector pump failure

Abstract

The US and Europe are increasingly tightening diesel-fuel quality specifications, particularly with respect to sulfur content. This trend is directing the oil industry toward progressively more severe types of hydrocatalytic manufacturing. Although usually beneficial in emissions terms, the overall consequences of such processing routes are not necessarily universally beneficial. In fact, there is strong evidence that automotive diesel fuel manufactured by severe hydrotreating may increase the risk of premature mechanical failure of certain classes of automotive fuel-injection pumps. Recent events in Sweden -- where strict, environmentally driven fuel specifications have been introduced -- have confirmed the existence of this risk. In response to these events, the Royal Dutch/Shell Group of companies has attempted to quantify and solve the problem of reduced diesel fuel lubricity in that market. These circumstances in Sweden, however, have potential implications for other markets. In the US, for instance, comparable pressures are driving manufacturers toward highly processed fuels that may lead to similar problems. The paper discusses lubricity, diesel fuel quality, quality advances, lubricity implications, field trials, test-bench results, lubricity improvement, and the global picture.