Method and apparatus for cleaning flue gases

US6508994B1 · kind B1 · utility

Assignee

• ABB Fläkt AB · SE

Inventors

• Stefan Ahman · Växjö, SE
• Nils Bringfors · Cervera de Pisuerga, ES

Key dates

• Filing date: Nov 15, 2000
• Grant date: Jan 21, 2003
• Expiry date: Nov 15, 2020

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01D2251/404
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

A method and an apparatus for cleaning flue gases with particulate slaked lime are described. In the method, burnt lime is dry-slaked with water to a moisture content of at least 5% by weight, and the slaked lime is contacted with the flue gases within 1 minute of the slaking. Preferably, the slaked lime is mixed with recirculated powdered lime from the flue gas cleaning before contacting it with the flue gases. The apparatus for dry-slaking of slaked lime comprises a feeding end for feeding burnt lime and, a discharge end for discharging slaked lime, a device for adding water, and mixers between the feeding and the discharge end, and the apparatus is characterized in that it comprises between the feeding end and the discharge end a first section and a second section which are separated by a first overflow edge, the sections comprising mixers which have rotatable horizontal shafts extending in the transverse direction of the apparatus, for mixing and feeding of burnt lime and water in the longitudinal direction of the apparatus from the feeding end towards the first overflow edge and from the first overflow edge towards a second overflow edge which is arranged at the discharge end.