2014 Volume 93 Issue 11 Pages 1213-1219
Synergistic effect of hydrothermal treatment (HTT) and oil agglomeration (OA) was investigated as a preparation method of coal-solvent slurry for a brown coal liquefaction process (BCL process). OA is a method to collect coal particles from a coal-water slurry by agglomeration of the coal particles and a solvent added to the coal-water slurry. In this study, a brown coal was treated by HTT at 320 ℃, and the HTT coal in the coalwater slurry was collected by OA. The OA were effectively performed by using recycled solvents obtained in the BCL process, because they had high affinity with the coal. The contents of ash and water in the collected HTT coal decreased to approximately half and 1/5, respectively, after both HTT and OA. Consequently, combination of the HTT and OA was found to be an effective method in view points of dewatering, de-ashing and preparation of a highly concentrated coal-solvent slurry for the BCL process. These effects contribute to a realization of the stable long-term operation of the liquefaction plant and increase in the oil productivity of the process.