Abstract: A method is provided for removing nitrogen oxides from waste gases, said method comprising the steps of oxidizing the nitrogen oxides in the waste gases by contacting the waste gases in a gas phase with an oxidizing agent to form NO.sub.2 ; absorbing the formed NO.sub.2 in an absorbing stage by contacting the oxidized waste gases with an absorbing agent to form an absorbing product while substituting fresh water for vaporized water in corresponding amounts; and processing the resultant absorbing product as a solution.

Abstract: A method of simultaneously removing SO.sub.x and NO.sub.x from waste gases. Using a known desulfurization process the waste gases free of the acidic components are contacted with an oxidizing agent in the gas phase for the oxidation of the oxygen of nitrogen contained in the waste gases. The formed NO.sub.2 is absorbed in a subsequent absorbing stage under previous addition of NH.sub.3 and the thereby obtained absorbing product is oxidized to form ammonium nitrate in a subsequent oxidation stage with atmospheric oxygen and then reconveyed into the desulfurization process.

Abstract: A method of manufacturing ammonium sulfate granules in which a starting solution of ammonium sulfate is spray dried, thereafter granulated by the addition of finely sprayed, highly concentrated water solution of ammonium sulfate.

Abstract: A process for removing acidic and other polluting components from flue gases exhausted from a boiler installation and passed through a preliminary air heater, then through a dust separator and desulphurization means; a partial current of the flue gases is branched off upstream of the air heater and passed through an auxiliary dust separator and a spray drier which is supplied with washing liquid from the desulphurization means, and thereupon the partial current is reunited with the main gas current downstream of the air preheater.

Abstract: Flue gas containing sulfur dioxide, carbon dioxide and other acidic components is desulfurized by washing it with an aqueous washing solution to which ammonia has been added in the stoichiometrically necessary amount for reaction with the sulfuroxides. The addition of the ammonia is so controlled that a predetermined amount of ammonium carbonate is maintained in the washing solution.

Abstract: Ammonium sulfate in dissolved form is dried in a gas current to obtain the ammonium sulfate in finely divided form. Thereafter the ammonium sulfate is quickly placed into a pelletizing device, subjected to a fine water spray, pelletized to substantially uniform grain size, and dried if necessary and/or desired.

Abstract: A pyrolysis reactor is operated by passing the waste products into a reactor provided with a heating unit; after completion of the pyrolysis passing the gaseous and vaporous products including suspended solids resulting from said pyrolysis into a partial oxidation zone wherein preheated air is added in an amount insufficient for complete combustion but sufficient to cause the exiting gas to have a temperature of at least 1000.degree., thereby causing decomposition of substantially all hydrocarbons present; then passing the partially oxidized gas through separate heat exchange means in contact, successively, with (1) the purified gas, (2) the air to be fed into the heating unit of the reactor and (3) with the air for said partial oxidation; then subjecting the partial oxidation gas to a purification; introducing air separately to said oxidation zone and heating means of the reactor; and passing the purified gas together with part of said added air into the heating unit of the reactor.

Abstract: Waste gas is contacted with a solution of a salt from a pollutant of the gas. This solution is obtained from another stage of the process used for cleansing or purifying the gas. The resulting mixture of gas and solution is subjected to vaporization so as to obtain a dry gaseous substance constituted by the waste gas and the evaporated solvent for the salt. The gaseous substance thus formed contains crystals of the salt as well as the pollutant present in the original waste gas. The salt crystals and other solid particles are removed from the gaseous substance in the form of a dry solids mixture. The gaseous substance is subsequently mixed with an absorption fluid such as an ammonia solution in order to wash out and redissolve any salt crystals which may remain in the gaseous substance and in order to remove the pollutant present in the original waste gas from the gaseous substance.