Abstract: A contamination purification system which can be installed in a narrow space to efficiently treat soil contaminated with a volatile organic compound, even when it is at a relatively low concentration, without needing a large-scale purification unit, and can effectively utilize the recovered volatile organic compound by its combustion/electric power generation unit.

Abstract: A combustion method for an internal combustion engine which prevents the occurrence of engine knock and improves fuel consumption and economy, by spray injecting part of the fuel used in one cycle into a combustion chamber, performing preliminary combustion of a diluted air-fuel mixture below combustible limits at a temperature lower than the self-igniting temperature of the fuel, then injecting the remaining fuel into the combustion chamber, and performing main combustion by flame propagation using spark plugs as ignition sources. Accordingly, the combustion method for an internal combustion engine of the present invention can attain stable combustion even at high air-fuel ratios and makes high compression ratios possible.

Abstract: There is disclosed a catalyst which hydrotreats hydrocarbons without need of presulfiding. The catalyst comprises a carrier of an inorganic oxide containing a sulfurizing agent and a water-soluble compound of two metals one of which belongs to the Group VI of the Periodic Table, while the other belongs to the Group VIII. The carrier has pores in which a precursor of a sulfide is formed. The coordination number of the closest Group VI metal found from the radial distribution function around the Group VI metal is less than 0.25. The function is obtained from the Fourier transform of the extended x-ray absorption fine structure of the precursor.

Abstract: A new catalyst, which is Ni-Mo metal loaded on zeolite-alumina carrier, provides efficient hydrotreatment of solvent for coal liquefaction and cracking of high boiling fractions, especially high boiling n-paraffins, whereby undesired accumulation of n-paraffins can be prevented and liquefaction operations can be stably performed over long periods of time.

Abstract: Disclosed is a catalyst for hydrotreating a coal liquefaction and circulation solvent, in which .gamma.-alumina carrier carries at least one metal of Group VI of the Periodic Table in an amount of from 15 to 15% by weight as the oxide thereof and at least one metal of Group VIII of the same Table in an amount of from 3 to 10% by weight as the oxide thereof and the pore distribution as measured by mercury pressure porosimetry satisfies the conditions that the pores having a diameter of from 40 to 600 .ANG. have a mean diameter of from 9 to 150 .ANG. and the capacty of the pores having a diameter falling within the range of the mean diametr plus/minus 10 .ANG. is 65% or more of the capacity of the pores having a diameter of from 40 to 600 .ANG.. The catalyst is highly active for both hydrogenation and denitrogenation of coal-liquefying solvents.