Co-pyrolysis of a mineral waste oil/coal slurry in a continuous-mode fluidized bed reactor

The main objective of this paper is to study the co-pyrolysis of a Spanish low rank coal and a mineral waste oil (MWO) slurry. The goal is to process the coal, handling it as a slurry by using a waste as the fluid component of the slurry in a continuous-mode preparative scale pyrolysis unit. It has been shown that a MWO/coal slurry can be successfully processed in a pulsed feeding fluidized bed reactor. Liquid and gases fractions have been analysed for organic products and metals. High yields of valuable light olefins such as ethylene and propylene and light aromatics as benzene, toluene, xylene and naphthalene derivatives have been obtained. The results show that both quantity and quality of gases and liquids obtained are significantly improved in relation to those obtained from coal. Special attention has been paid to the fate of metals contained in the MWO/coal slurries and their distribution into the co-pyrolysis products. In particular, the distribution of six metals (Cd, Ni, Pb, Cu, Cr, V) has been studied. The data show that metals under study are totally or partially trapped in the char formed during co-pyrolysis. This way the contents of Pb, Cu, V and Ni in the pyrolysis products leaving the reactor is substantially lower than in the feeding what will facilitate the obtention of valuable products. (C) 2002 Elsevier Science B.V. All rights reserved.