Studies on Sulfur Oxides Removal from Flue Gas by Dry Limestone Injection Process (I)

Abstract

The dry limestone injection process was considered to be one of the most simplest processes for removing sulfur oxides from flue gas in a steam power plant boiler. Therefore, researches of the process were conducted earnestly in Germany, U. S. A. and Japan.This is the first report of our research on the dry limestone injction process which were carried out at the Central Research Institute of Electric Power Industries. This report contains the results of thermodynamic considerations on the reaction of the dry limestone injection process in a boiler which involve limestone calcination and sulfur dioxide fixation.Their results are concluded as follows.(1) Limestones or hydrated limes decompose to calcium oxide at above 770°C or 400°C, respectively, when the carbon dioxide and water vapor concentrations are 12 and 10 per cent in flue gases.(2) The reaction of calcium oxide with sulfur dioxide will occure at below 1250°C when the concentrations of sulfur dioxide and oxygen are 0.2 and 3 per cent in flue gas.