SO₂ Removal by Limestone in a 71MWe Pressurized Fluidized Bed Combustor

Part.2 SO₂ Removal during Petroleum Coke/Coal Mixture Combustion

Abstract

SO₂ capture by limestone was conducted within a 71MWe pressu-rized fluidized bed combustor. Mixtures of high-sulfur petroleum coke and low-sulfur coal with different mixing proportion were used as fuels. The effect of the size distribu-tion of limestone on SO₂ removal efficiency was evaluated. The SO₂ removal efficiency was well correlated with feed rate of external surface area of limestone greater than the cut size of cyclone that recycled elutriated fine particle into the bed. A semi-theoretical correlation between size distribution of fed limestone and SO₂ removal efficiency was proposed. This model assumed the uniform formation of SO₂ in the dense bed, SO₂ cap-ture in the dense bed by fresh limestone of fractions greater than elutriation size, and SO₂ capture in the freeboard by fresh limestone of fractions smaller than the elutriation size but greater than the cyclone cut size.