Abstract: The present invention relates to a process for the purification of off-gases containing nitrogen oxides. An off-gas is passed through a reactor in admixture with ammonia or an ammonia precursor over a plurality of spaced catalyst beds under conditions to reduce the nitrogen oxides to nitrogen gas while heat is liberated. After the gas stream has obtained a desired temperature, the gas flow is reversed.

Abstract: The present invention relates to the production of elemental sulphur from sulphur dioxide and hydrogen sulphide by the Claus reaction.To obtain elemental sulphur, into a catalyst bed divided into at least two parts the reaction gas having temperature of not less than 120.degree. C. is introduced in the direction perpendicular to the cross-section along which the catalyst bed is divided. At least into one part of the catalyst bed sulphur dioxide and hydrogen sulphide are introduced at a temperature below the dew point of sulphur. Between parts of the catalyst bed resulting from its division intermixing and/or cooling of the reaction gas is effected. In at least one part of the catalyst bed the direction of supply of the reaction gas is reversed when the difference in temperatures of this gas at the inlet and outlet of the second part of the catalyst bed reaches 50.degree.-150.degree. C.

Abstract: A method of preparing methanol consists in that a synthesis-gas containing carbon oxides and hyddrogen is passed through a fixed bed of a copper-containing catalyst under pressure of 3.0-15.0 MPa at a temperature of from 150.degree. to 300.degree. C. The catalyst is divided into two parts either in an equal proportion or in a smaller/greater ratio equal to 0.5-1. The gaseous mixture obtained after passing the first part of the catalyst bed is stirred prior to the supply thereof to the second part of the catalyst bed. As a result, the reaction mixture is formed containing the aim product. Each subsequent direction of passing the synthesis-gas through the catalyst bed and that of removing the reaction mixture are changed to opposite with respect to the previous direction.

Abstract: The method of catalytic cleaning of exhaust gases from organics and carbon monoxide consists in that an exhaust gas is passed through a bed of deep oxidation catalyst. The process is carried out with a temperature of 250.degree.-700.degree. C. The catalyst is made up of two parts. The exhaust gas is passed through a first part of the catalyst bed, stirred and passed through a second part of the catalyst bed. The stirring is continued until the temperature drop in the stream of the gas which is being cleaned is not over 50.degree. C. at the entrance into the second part of the catalyst bed, and the flow of the gas is reversed at regular intervals during the cleaning.

Abstract: A method of preparing sulphur trioxide by the oxidation of sulphur dioxide contained in a reaction mixture in a stationary catalyst bed wherein the direction of the movement of the reaction mixture flow along the catalyst bed is reversed periodically each 10-200 minutes, or the temperature of said reaction mixture is changed in front of the catalyst bed from a temperature of 20.degree.-200.degree. C. to a temperature of 350.degree.-600.degree. C. each 10-200 minutes.