Abstract: A cooling method of a hydrotreating plant having a desulfurization section (1) including a furnace (12) for heating liquid to be processed, reactors (14, 15) for hydrotreating sulfur to generate hydrogen sulfide, a hydrogen sulfide absorber (19) for absorbing the hydrogen sulfide generated in the reactors (14, 15), and a compressor (21) for compressing and transferring fluid from the hydrogen sulfide absorber (19) toward the reactors (14, 15), the cooling method comprising the steps of gradually depressurizing the hydrotreating plant at the desulfurization section (1) to a pressure level at which reactor material does not embrittle and gas does not leak due to difference of mechanical thermal expansion in the plant after stopping supply of the liquid to be processed, operating the compressor (21) approximately at the maximum rotation number, and completely extinguishing burners (12A, 12B) in the furnace (12) during plant shutdown operation.

Abstract: A cooling method of a hydrotreating plant having a desulfurization section (1) including a furnace (12) for heating liquid to be processed, reactors (14, 15) for hydrotreating sulfur to generate hydrogen sulfide, a hydrogen sulfide absorber (19) for absorbing the hydrogen sulfide generated in the reactors (14, 15), and a compressor (21) for compressing and transferring fluid from the hydrogen sulfide absorber (19) toward the reactors (14, 15), the cooling method comprising the steps of gradually depressurizing the hydrotreating plant at the desulfurization section (1) to a pressure level at which reactor material does not embrittle and gas does not leak due to difference of mechanical thermal expansion in the plant after stopping supply of the liquid to be processed, operating the compressor (21) approximately at the maximum rotation number, and completely extinguishing burners (12A, 12B) in the furnace (12) during plant shutdown operation.

Abstract: A process for the production of a high viscosity index, low viscosity lubricating base oil having a kinematic viscosity of 3.0 to 7.5 mm.sup.2 /s at 100.degree. C., a viscosity index of 120 or more and a pour point of -10.degree. C. or less, while simultaneously producing a high quality fuel oil, which includes subjecting a mixture stock oil of (a) at least one of a heavy gas oil fraction and a vacuum gas oil fraction and (b) a slack wax to hydrocracking in the presence of an amorphous silica alumina catalyst, separating the cracked product into a fuel oil fraction and a lubricating oil fraction by atmospheric distillation, and subsequently subjecting the lubricating oil fraction to dewaxing, optionally applying at least one of solvent refining and hydrofinishing.

Abstract: This invention relates to a method for preparing fine graphite particles which can be used as a highly functional graphite material in wide applications. According to this method, foliated fine graphite particles having a high aspect ratio and hence well-developed anisotropy can be prepared, without formation of secondary particles, by dispersing expanded graphite particles into a liquid and then exposing them to ultrasonic waves. Articles molded of the resulting foliated fine graphite particles exhibit high electrical conductivity and thermal conductivity.