Abstract: In a coal-water slurry producing system, low grade coal is wet-ground to not greater than 3 mm in particle size to produce a ground coal slurry. An upgrading treatment is applied to the ground coal slurry under a pressurized hydrothermal atmosphere not less than 300.degree. C. to produce an upgraded coal slurry. The upgraded coal slurry is subjected to a dehydration treatment to produce an upgraded coal cake and a filtrate. A final coal-water slurry is produced from the upgraded coal cake. The filtrate is recycled for producing the ground coal slurry. A slurry transfer mechanism is provided in the coal-water slurry producing system for ensuring a stable transfer of the upgraded coal slurry from a high-pressure slurry vessel to a low-pressure slurry vessel.

Abstract: Disclosed is a method of producing water slurry of SDA asphaltene by dispersing residue resulting from solvent deasphalting of petroleum vacuum residue produced in refineries, which has low viscosity even at a high solid concentration and is stable for a long period of time, in industrial scale under stable operation. The method comprises a grinding step of grinding the SDA asphaltene with water in a grinding apparatus in the presence of a dispersing agent, followed by a stabilizing step of stirring the resulting slurry to stabilize it. In the grinding step a suitable amount of a thickener such as carboxymethyl cellulose is added. Grinding is preferably carried out at a temperature not higher than 80.degree. C. Jacketed ball mills are conveniently used. In the stabilizing step a stabilizer such as Attapulgus clay is added after stirring the slurry to decrease viscosity thereof and stirring is continued.

Abstract: The present invention relates to a process for the manufacture of hydrogen sulfide by reacting sulfur and hydrogen which comprises two hydrogenation reactions. The first hydrogenation reaction of the present invention comprises the steps of supplying hydrogen gas in a reactor containing sulfur at least a part of which is in a liquid phase at a temperature of not lower than 250.degree. C., and reacting the liquid sulfur and the hydrogen gas to produce a crude hydrogen sulfide effluent gas in the reactor. The sulfur vapor contained in the effluent gas is further reacted with fleshly added hydrogen gas in the second hydrogenation reaction to further concentrate the resulting hydrogen sulfide.

Abstract: It has been believed that the Claus reaction in water without additive gives no more than very low conversion and some additive such as buffer or catalyst must be used to attain satisfactory H.sub.2 S conversion.However, it was discovered that when H.sub.2 S and SO.sub.2 are introduced in water simultaneously and continuously for hours, the conversion increased gradually and became steady at high level. The present invention was accomplished base on this inventive knowledge.