Metallgesellschaft Aktiengesellschaft

Amec Foster Wheeler Energia Oy

Vereinigte Aluminium-werke Aktiengesellschaft

Sumitomo Shi Fw Energia Oy

Rolf Graf

Lothar Reh

Reijo Kuivalainen

Martin Hirsch

Ludolf Plass

Volker Sparwald

Winfried Gutperl

Ernst Weckesser

Tobias Brand

Harald Kessler

Eberhard Bohm

Maria-Helena Möbs

Michael Schroter

Sulfurous fuel and CaCO-containing sorbent are combusted in a furnace of a circulating fluidized bed boiler. A dry circulating fluidized bed scrubber includes a reactor with water and Ca(OH)feeds for converting SOin the exhaust gas to CaSOand CaSOand a dust separator in gas flow connection with the reactor. A discharge removes CaO-containing bottom ash from the furnace. A classifier classifies a portion of the removed CaO-containing bottom ash into coarse and finer portions. A fine ash channel conveys some of the finer bottom ash portion from the classifier to a grinder. A ground ash channel conveys some of the ground bottom ash portion from the grinder to a hydrator to hydrate CaO in the ash to Ca(OH). A hydrated ash channel conveys some of the Ca(OH)from the hydrator to the dry circulating fluidized bed scrubber as a sorbent.

Method of and apparatus for combusting sulfurous fuel in a circulating fluidized bed boiler

A scrubber for removing pollutant compounds from a gas stream. At least one gas channel introduces the gas stream to a lower portion of the scrubber. An inlet chamber directs the gas stream upwards to form a vertical gas stream. A constriction section has a vertical axis of symmetry and includes a centrally arranged venturi nozzle, and is above and in flow connection with an upper end of the inlet chamber for accelerating the vertical gas stream. A reaction chamber is arranged above and in flow connection with the constriction section. A reagent in the reaction chamber converts pollutant compounds in the gas stream to reaction products. A discharge channel in flow connection with the reaction chamber discharges gas and particles including the reaction products from the reaction chamber. A particle separator separates particles from the gas. A return channel recycles a portion of the particles to the reaction chamber.

Method of and a scrubber for removing pollutant compounds from a gas stream

Disclosed is a process of carrying out a combined gas turbine and steam turbine process of increased efficiency. A fuel gas is produced at a temperature of from 900.degree. to 1100.degree. C. in a circulating fluidized bed by a gasification of 70 to 95 wt. % of the carbon contained in the carbonaceous material and is treated at a temperature of from 850.degree. to 950.degree. C. with suspended solids consisting of calcium hydroxide, calcium oxide and/or calcium carbonate-containing solids to remove pollutants. The main portion of the fuel gas is burnt to produce a gas which is used to operate the gas turbine and which contains at least 5% by volume oxygen and is at a temperature of at least 1000.degree. C. Combustion of the carbonaceous gasification residue to produce process steam is performed in a second circulating fluidized bed at a temperature of from 800.degree. to 950.degree. C. under near-stoichiometric conditions by a treatment with oxygen-containing gases, which are supplied on different levels in at least two partial streams and mainly consist of exhaust gas from the gas turbine. The desulfurized fuel gas is preferably cooled to a temperature in the range from 350.degree. to 600.degree. C. and is freed from halides.

Combined gas and steam turbine process

Disclosed is a process for removing sulfur oxides and optionally other gaseous pollutants from flue gases by means of a reactant which is contained in a circulating fluidized bed and contains sodium, potassium, calcium and/or magnesium as a cation and oxide, hydroxide and/or carbonate as an anion. The adaptation to all operating conditions of the plants by which the flue gas is supplied is simplified in that pollutants are removed from the flue gases when the temperature of the mixture of flue gas and reactant is not in excess of 50.degree. C. above the dew point temperature of water vapor. The reactant is selectively charged at different locations in a dry form, on the one hand, and as an aqueous solution or suspension, on the other hand, the form in which the reactant is charged being controlled in dependence of the temperature and the SO.sub.2 content of the purified gas. If the reactant is charged in a liquid phase it has suitably a solids content of 5 to 30 wt. %, the temperature of the mixture of flue gas and reactant is maintained between 3.degree. and 30.degree. C. above the dew point temperature of water vapor and the means suspension density in the fludized bed reactor is maintained between 0.2 and 2 kg/m.sup.3.

Process of removing pollutants from flue gas

In a process of removing pollutants consisting substantially of sulfur oxides from exhaust gases at temperatures below 150.degree. C. by means of a sorbent which contains calcium carbonate, calcium oxide and/or calcium hydroxide and which is included in a circulating fluidized bed system consisting of a fluidized bed reactor, a separator and a return line, a complete utilization of the sorbent is achieved in that a partial stream of laden sorbent is withdrawn from the circulating fluidized bed and is subjected at a temperature of 600.degree. to 1200.degree. C. to an oxidizing treatment, a major part of the sorbent that has been subjected to an oxidizing treatment is recycled to the circulating fluidized bed, and a partial stream which contains the sorbent mainly in the form of calcium sulfate is removed from the process. Fresh sorbent is supplied to the circulating fluidized bed and/or to the stage for the oxidizing treatment at the rate at which said partial stream is removed from the process.

Process of removing pollutants from exhaust gases

Hydrogen fluoride is removed from gases by introducing the gases into a fluidized-bed reactor to form a gas-solid suspension, entraining a major part of the solids in an upward direction separating the solids entrained by the gases without prior removal of the solids from the gas-solid suspension, by means of an electrostatic precipitator.

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Friedrichsdorf, Germany

Rolf Graf