Method of regulating the amount of reducing agent added during catalytic reduction of NO.sub.x contained in flue gases

US4565679A · kind A · utility

Assignee

• L & C Steinmuller GmbH · DE

Inventors

• Stanislaw Michalak · Bergneustadt, DE
• Klaus Weber · Hamburg, DE
• Jurgen Meier · Leverkusen, DE

Key dates

• Filing date: Oct 17, 1984
• Grant date: Jan 21, 1986
• Expiry date: Oct 17, 2004

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01D53/8625
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

A method of regulating the amount of reducing agent added, especially NH.sub.3 in the case of the catalytic reduction of NO.sub.x of flue gases which originate from a combustion installation which is fired with fossil fuels. The adjustment value for the quantity to be added is determined in response to a prescribed reducing agent/NO.sub.x stoichiometry factor from the quantity of combustion air supplied to the combustion installation or from the exiting quantity of flue gas, and from the NO.sub.x concentration downstream ahead of the catalyzer. Regulation is effected by influencing the stoichiometry factor. The NO.sub.x concentration downstream after the catalyzer is returned to the regulation process as the primary correction value, and the reducing agent concentration downstream after the catalyzer, and the flue gas temperature ahead of the catalyzer, are returned to the regulation process as the secondary correction values. The set stoichiometry factor is influenced such that while maintaining the emission limit value as the desired value of the primary correction value, and while maintaining a reducing agent concentration downstream after the catalyzer below a prescribed fixed …