Abstract: Parts to be cleaned, degreased, or having paint stripped therefrom, by a solvent such as a halogenated hydrocarbon are lowered into and lifted out of a tank via an enclosure disposed above the tank. A pair of doors at the top opening and a second pair of doors at the bottom opening of the enclosure allow isolation of the enclosure from the tank below and from the outside environment above. Parts are lowered into the enclosure with the top doors open and the bottom doors closed. They are then further lowered into the tank for cleaning, degreasing or paint stripping with the top doors closed and the bottom doors open. After cleaning, degreasing or paint stripping, the parts are lifted back into the enclosure and the bottom doors are closed.

Abstract: Gasoline hydrocarbons are produced by a catalytic conversion of methanol under a pressure of about 5 to 100 bars and at temperatures of about 250.degree. to 500.degree. C. The high-hydrocarbon product of the conversion is cooled so as to condense gasoline hydrocarbons. Tail gas is separated and then compressed and recycled to the conversion. In a heating step, liquid methanol is injected into a mixture of tail gas and methanol vapor and the liquid methanol is entirely evaporated. The resulting mixture of tail gas and methanol vapor is heated by about 10.degree. to 40.degree. C. by an indirect heat exchange with the high-hydrocarbon product. The heating step consists of the injection of liquid methanol and of the heating of the mixture of tail gas and methanol vapor and is repeated at least twice. The mixture at a temperature of about 280.degree. to 360.degree. C. is supplied to the catalytic conversion.