Abstract: In methods for transporting an aqueous slurry of particulate solids in a pipeline wherein the aqueous slurry has an effective viscosity greater than water and is pumped through the pipeline by at least one centrifugal pump wherein a flushing fluid is used to maintain the bearing surfaces in the centrifugal pump free of particulate solids, an improvement comprising; the use of a thickened aqueous flushing fluid having a viscosity equal to at least about 80 percent of the viscosity of the aqueous slurry.

Abstract: Low-sulfur and low-ash gaseous, liquid and solid fuels are made from coal by a process which first subjects the coal to solvent extraction and hydrotreatment under hydrodesulfurizing conditions in a coal liquefaction zone to reduce the organic sulfur content of the coal. The effluent is divided into a low-solids product which contains most of the extract and a high-solids product which contains most of the remaining inorganic sulfur and other mineral matter. The low-solids product stream which contains extract and solvent is subjected to a forming step to yield low-ash and low-sulfur pellets. The high-solids product stream is subjected to gasification to yield hydrogen for use in the liquefaction step. The process is particularly adapted to supply the energy needs of a steel plant, including the required coke.