Process and apparatus for removing dust, sulfur compounds and nitrogen oxides from combustion exhaust gases

US5219543A · kind A · utility

Assignee

• Metallgesellschaft AG · DE

Inventors

• Werner Weisweiler · Remchingen, DE
• Erhard Herrmann · Leverkusen, DE
• Wolfgang Fennemann · Karben, DE
• Harald Sauer · Frankfurt am Main, DE
• Bernd Thone · Friedberg, DE

Key dates

• Filing date: Dec 5, 1991
• Grant date: Jun 15, 1993
• Expiry date: Dec 5, 2011

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02A50/20
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

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.