Metallgesellschaft Aktiengesellschaft

Basf Aktiengesellschaft

Stadtwerke Munster Gmbh

Bayer Aktiengesellschaft

Heinz Neumann

Hugo Grimm

Karl H Dorr

Gunter Lailach

Rudolf Gerken

Wolfgang Fennemann

Karl-Heinz Dorr

Arend Werner

Guenther Huber

Michael Tacke

Manfred Munzinger

Bruno Triebskorn

Egon Winkler

Walter Beitelschmidt

Hans-Juergen Bender

Norbert Olhms

Martina Schulz

Volker Esswein

Peter Ahrens

Reinhard Oettl

Matthias Stahl

Norbert Ohlms

Gerhard Ruf

Ralph Hamleser

An electrolysis cell for preparing alkali metals from a liquid alkali metal heavy metal alloy, including a tube arranged essentially horizontally having a closure device at each of the two ends of the tube. At least one solid electrolyte tube arranged concentrically in the tube and oriented with openings towards one end of the tube such that a first annular gap for conducting a liquid alkali metal, which forms an anode, is present between the inside of the tube and the outside of the solid electrolyte tube. An interior space in the solid electrolyte tube, sealed off from an alloy inlet, first annular gap and an alloy outlet, accommodates liquid alkali metal that can be used as a cathode.

Electrolysis cell for producing alkali metal

To effect a quasi-isothermal catalytic reaction of SO.sub.2 to SO.sub.3, a plurality of consecutive rows of banks of cooling tubes, are provided in the bed of shaped catalyst bodies in a contact reactor in such a manner that the banks of succeeding rows are staggered from the banks of the preceding rows. The distance between the cooling tubes in the banks is so selected that a penetration of entire catalyst bodies into the banks will virtually be prevented. The banks are so designed that the pressure drop of the gas in the banks is approximately the same as the pressure drop in the layer of catalyst between the bank. The distance between the banks is larger than the width of the banks.

Contact reactor for a quasi-isothermal catalytic oxidation of SO.sub.2

In flue gases or other humid exhaust gases which are relatively cold and contain SO.sub.2, NO.sub.2 and other gaseous pollutants, the SO.sub.2 content is oxidized to SO.sub.3 and the NO content is reduced by a catalytic treatment, the SO.sub.3 content is condensed as sulfuric acid and other gaseous pollutants are removed by being scrubbed with aqueous liquids at low temperatures. In order to heat up the flue gas to the temperature required for the catalysis, the flue gas is heated up in a first heating-up stage by an indirect heat exchange with the catalytically treated gas before the catalytic treatment, the heated-up gas is heated up further in a second heating-up stage to the temperature required for the catalytic treatment, the catalytically treated gas which has been cooled in the first heating-up stage is cooled further in an indirect heat exchanger below the dew point temperature of sulfuric acid and is subsequently fed to an SO.sub.3 condenser. The remaining sulfuric acid vapor is absorbed by sprayed dilute sulfuric acid to form a dilute sulfuric acid having a predetermined concentration, the gas leaving the SO.sub.3 condenser is scrubbed in a scrubber with a sprayed aqueous liquid and is thus cooled to 40.degree. to 60.degree. C. and the purified gas is reheated to the required chimney inlet temperature.

Process of purifying flue gases

Flue gases or other contaminated humid exhaust gases which contain SO.sub.3 are cooled by an indirect heat exchange in a heat exchanger to a temperature below the dew point temperature of sulfuric acid and are cooled further to a predetermined temperature in an SO.sub.3 condenser by means of dilute sulfuric acid, which is sprayed to flow in a countercurrent to the gas, whereby dilute sulfuric acid having a predetermined concentration is condensed. The gas leaving the SO.sub.3 condenser is scrubbed and cooled to a temperature from 40.degree. to 55.degree. C. in a fine scrubber by a treatment with a sprayed aqueous liquor. The exit gas is reheated to a predetermined temperature in a reheater by a treatment with sprayed dilute sulfuric acid from the SO.sub.3 and after the condensation of SO.sub.3 is passed through a filter. Dilute sulfuric acid from the reheater is sprayed into the SO.sub.3 condenser. The temperature of the gas in the reheater is so selected that the water which has been absorbed is not condensed but remains in the gaseous effluent. The exit temperature of the gas leaving the heat exchanger is approximately so selected that the temperature at which dilute sulfuric acid becomes available is approximately the same as the temperature of the gas in the reheater. The rate at which dilute sulfuric acid is sprayed is so adjusted that the dilute sulfuric acid withdrawn from the fine scrubber is at a temperature which is approximately the same as the required exit temperature of the gas leaving the SO.sub.3 condenser.

Cleaned flue gases normally accumulate as steam-saturated gases with temperatures of from 40.degree. to 55.degree. C. after wet cleaning processes for the removal of sulfur and/or nitrogen compounds. Before being let off through a stack, however, these gases have to be heated to at least 72.degree. C. This invention relates to a process for reheating flue gases after wet cleaning.

Process for cleaning flue gases

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Bad Konig, Germany

Heinz Neumann