Liquefaction low severity conditions : The catalyzed depolymerization as a pretreatment for coal liquefaction
This project concerns the investigation of the basic coal liquefaction process by reaction of a sub-bituminous coal in two stages of increasing severity. Process variables include the influence of the amount of Zn incorporated during the first stage, the residence time, the initial hydrogen pressure and the role of catalysts (1 wt% Mo or 5 wt% Fe) at constant temperature (400 C) and in the absence of solvent. The results suggest that the first stage or pretreatment reaction involves very mild conversions but improves the treated coal with respect to the raw coal, allowing a better coal hydrogenation during the second stage. High yields are already obtained with the lowest severity conditions used; better oils/asphaltenes ratios are obtained with longer residence times and 15 MPa of initial H(2) pressure. In an attempted simulation of a continuous process, a mixture of coal asphaltenes has been coprocessed at the above conditions, after studying the optimum asphaltenes percentage in the feed mixture. Conversions from 86 to 93% and oil/asphaltenes ratios up to 1.5 have been reached. 30 minutes of hydrogenation time and 15 MPa of initial hydrogen pressure appear to be the best conditions, as is also the case when coal is the feed.
Bibliographic Reference: EUR 13576 EN (1991) 104 pp., MF, ECU 8
Record Number: 199110594 / Last updated on: 1994-12-02
Original language: en
Available languages: en