Abstract
Victorian brown coal was hydroliquefied with two kinds of solvents in the presence of iron/sulfur catalyst using a process development unit (PDU) with three stirred tank reactors in series.
The effects of solvent properties on the progress of the liquefaction reaction and the actual state in the plural reactors were investigated by analysing product yields and liquid samples from each reactor. Vaporization of solvent fraction and actual residence time of the liquid phase in the reactors were also determined by using the results of these analyses.
The solvents used were a creosote oil and a recycling solvent recovered from other PDU operations.
Oil yield with the recycling solvent in the first reactor was higher than that with the creosote oil although the liquefaction reactions mainly took place in the first reactor with both solvents. However, oil yield through three reactors was almost the same with both solvents. These results indicate that the hydrogen donation from the solvent was effective at the early stages of liquefaction, and the hydrogen shuttling by solvent with catalyst was effective for hydroliquefaction of heavy products such as preasphaltenes derived from the coal. These conclusions were supported by analyses of the amount of transferred hydrogen to the products and liquid phase in the reactor.
These results show that the vaporization and actual residence time of hydrogenated solvent were larger than that of non-hydrogenated solvent such as creosote oil.
