Coal liquefaction catalysis: Metals deposition in the presence or absence of coal ash

Abstract

Catalysts, aged in an ebullating bed reactor, have been characterized for carbon and metals deposition. It appears that the amount of carbon on the catalyst is more dependent upon the reactor temperature than on coal type; this carbon deposition attains a maximum value within the first few days of a run. Metals deposition does vary with coal. The presence of coal ash in a hydrotreater feed may significantly alter metals deposition. For iron, calcium and vanadium deposition is less when coal ash is present and the maximum content of these metals is attained at an earlier time on-stream when ash is present. Sodium, on the other hand, may be deposited to a much greater extent when coal ash is present. Titanium deposition appears to be independent of the coal ash concentration.