Influence of Lime/Limestone Addition on the SO₂ and NO Formation during the Combustion of Coke Pellet

Abstract

Isothermal combustion experiments of coke pellet mixed with lime/limestone had been performed to investigate the effect of lime/limestone addition on the reduction of NO and SO₂ emission. The coke pellets were combusted between 700°C and 1300°C under pure oxygen atmosphere. Combustion kinetics and conversion data of SO₂ and NO were obtained from the thermogravimetry of coke pellet and gas analysis data. Adsorption of NO by lime mixed with coke was not occurred in the experimental ranges. It was possible to reduce most of SO₂ emission below 900°C by adding lime/limestone to coke. However, the reduction efficiency of SO₂ by the addition of lime/limestone decreased with increasing temperature due to the decomposition reaction of CaSO₄. The variation of the conversion to NO and SO₂ with the combustion conditions during the combustion of coke pellet was compared with the results of thermodynamic calculation.