Basf Aktiengesellschaft

Texaco Development Corporation

Hans Gettert

Knut Kaempfer

Franz J Broecker

Bruno Sander

Hans Henning Schneehage

Ernst-Juergen Schier

Dietmar Werner

Siegfried Marquardt

Arnulf Jeck

Hermann Dieter Fromm

Wilhelm Berkel

K Robert Mueller

Martin Molzahn

Wastewaters which contain carbon black and ash and originate from high temperature processes and in which the carbon black is present in a very finely divided state and partially in a colloidal state are treated and disposed of by a process in which the wastewater is treated with calcium carbonate or calcium hydroxide and an organic flocculant and subjected to a two-stage filtration and the resulting filter cake containing carbon black and ash is subjected to an aftertreatment with an aqueous iron salt solution.

Treatment and disposal of wastewaters containing carbon black and ash

H.sub.2 S-containing gases are desulfurized by direct catalytic oxidation of the H.sub.2 S to elemental sulfur with an oxygen-containing gas at elevated temperatures by a method in which the catalyst used is a supported titanium dioxide catalyst containing from 0.1 to 25% by weight of nickel oxide and from 0 to 10% by weight of aluminum oxide, the percentages being based on the supported catalyst.

Desulfurization of H.sub.2 S-containing gases

Gases containing CO and/or CO.sub.2 are purified by removing sulfur compounds and other impurities by catalytic reaction at elevated temperatures by a process in which the gases to be purified are passed directly through a catalyst charge containing a Cu/ZnO catalyst prepared by thermal decomposition of a mixed crystalline compound of zinc hydroxide carbonate, and the space velocity is set at 500-5,000 m.sup.3 (S.T.P.) per m.sup.3 of catalyst per hour. Preferably, the catalyst used is a Cu/ZnO catalyst which is prepared by thermal decomposition of a catalyst precursor of the general formula

Purification of gases containing CO and/or CO.sub.2

H.sub.2 S-containing gases are desulfurized by direct catalytic oxidation of the H.sub.2 S to elementary sulfur by means of oxygen-containing gases in a tube reactor, with indirect removal of the heat of reaction by means of a coolant and with condensation of the sulfur formed, wherein either the catalyst is present in the jacket space around the tubes and the coolant is present in the tubes of the reactor or the coolant is present in the jacket space around the tubes and the catalyst is present in the tubes of the reactor, and the catalyst fills the tubes of the tube reactor or the jacket space around the tubes over the entire cross-section of the tubes or the jacket space respectively, the exit temperature of the gaseous reaction mixture leaving the tube reactor is kept at 180.degree.-400.degree. C. and the sulfur formed in the tube reactor is separated out of the reaction mixture, obtained in the reactor, in a condensation stage downstream of the reactor.

A process for preventing deposits in the pipes of waste heat boilers employed for cooling gases in the partial autothermal oxidation of fossil fuels to prepare hydrogen or synthesis gases, wherein the pipes are flushed, at the operating temperature, with hydrogen-containing gases which contain little or no H.sub.2 S.

Method of prevention of deposits in the pipes of waste heat boilers

To isolate ammonia from gas mixtures containing ammonia and carbon dioxide, the gas mixture is first partially absorbed in a solvent, with residence times of at most 0.1 second, and the non-absorbed gas is then separated from the solution obtained. The solution is then subjected to a first desorption stage, in which only the ammonia present in an excess over a molar ratio of 3 parts of ammonia to 1 part of carbon dioxide is expelled by heating, and the entrained carbon dioxide is washed out of the expelled ammonia by means of solutions containing free ammonia. The solution remaining after the first desorption stage is substantially freed from ammonia and carbon dioxide in a second desorption stage and the expelled gas, containing solvent, together with fresh gas mixture is fed to the adsorption stage, while the solvent obtained from the second desorption stage is employed for the absorption.

Isolation of pure ammonia from gas mixtures containing ammonia and

The reaction zone of a free-flow refractory lined partial oxidation gas generator is preheated by the complete combustion of fuel gas, supplied by means of a preheat burner, with air at atmospheric pressure. The preheat burner is replaced by the main process burner and the heating is continued by the complete combustion of said fuel gas and air at atmospheric pressure. The main burner is then made pressure tight to the reaction zone, and the heating is continued. When the temperature of the reaction zone reaches the temperature for ignition of the autothermal partial oxidation reaction of the liquid hydrocarbonaceous fuel and free-oxygen containing gas in the presence of a temperature moderator, fuel gas and air are cut-off, and are respectively replaced by a stream of said liquid hydrocarbonaceous fuel, optionally in admixture with a temperature moderator, and a separate stream of free-oxygen containing gas, optionally in admixture with a temperature moderator. After ignition, the partial oxidation reaction takes place in the reaction zone, and the gas generator is brought up to operating pressure. In the event of temporary shut down of the gas generator, the streams of liquid hydrocarbonaceous fuel, steam, and free-oxygen containing gas are shut-off and a stand by temperature may be maintained in the reaction zone to allow quick start-up by switching the feedstreams to the main burner back to fuel gas and air.

Process for the partial oxidation of liquid hydrocarbonaceous fuels

Gas mixtures containing ammonia and carbon dioxide are separated by fractional absorption in a solvent. The gas mixture and solvent are intimately mixed in a zone, the residence time of the gas in the mixing zone being restricted to a maximum of 0.1 second. Non-absorbed gas and solvent are then separated from one another and the gas separated off is subjected to a further absorption if necessary.

Growing community of inventors

Gross-Sachsen, Germany

Hans Gettert