Metallgesellschaft Aktiengesellschaft

Werner Weisweiler

Wolfgang Fennemann

Erhard Herrmann

Harald Sauer

Bernd Thone

Bernd Hochstein

Burkhard Retzlaff

The process of removing dust, sulfur compounds and nitrogen oxides from combustion exhaust gases, comprising mixing a combustion exhaust gas with ammonia; feeding Ca(OH).sub.2 and FeSO.sub.4 to a fluidized bed reactor containing mixed solids including fly ash, iron sulfates and calcium compounds, especially Ca(OH).sub.2, CaCO.sub.3, CaO, CaSO.sub.4 and CaSO.sub.3 ; supplying an ammonia-containing exhaust gas mixture to the fluidized bed reactor as a fluidizing gas; operating the fluidized bed reactor at a temperature between 300.degree. and 450.degree. C. to form a reacted exhaust gas; supplying the reacted exhaust gas to a multistage electrostatic precipitator having a first stage and additional stages; recycling solids collected in the first stage to the fluidized bed reactor; and recycling one portion of additional solids collected in the additional stages to the fluidized bed reactor and discharging another portion of the additional solids.

Process and apparatus for removing dust, sulfur compounds and nitrogen

A process is disclosed wherein NO contained in a gas is reduced by means of NH.sub.3 as a reducing agent. A mixture of the NO-containing gas and NH.sub.3 is reacted at 290.degree. to 450.degree. C. in the presence of a catalyst, which comprises a support of SiO.sub.2 and contains 5 to 15% by weight manganese sulfate and iron sulfate. The mole ratio of manganese sulfate and iron sulfate, which is calculated as FeSO.sub.4, is between 1:10 and 10:1. The support has a pore volume of 0.6 to 1.6 ml/g and an average pore diameter of 10 to 100 nm.

Process of catalytically reducing NO

A process of catalytically reducing NO contained in a gas which contains SO.sub.2. The NO is reduced with NH.sub.3, which is admixed to the gas which contains SO.sub.2 and NO. The mixture is supplied to the catalyst at a rate of 0.2 to 20 standard liters per minute and per gram of catalyst and is reacted with the latter in a fluidized bed at a temperature between 185.degree. and 500.degree. C. and under normal pressure. The catalyst has a particle size between 0.1 and 3 mm and is composed of an acid support and an active component, which consists of V.sub.2 O.sub.5, MnO.sub.2, CuO, Fe.sub.2 O.sub.3, NiO and/or Y.sub.2 O.sub.3 and has been applied to the support in a quantity of 0.5 to 20% by weight. It is proposed that part of the catalyst is removed from the fluidized bed and is regenerated and returned to the fluidized bed.

Growing community of inventors

Remchingen-Singen, Germany

Werner Weisweiler