Kinetic Evaluation of Lime for Medium-Temperature Desulfurization in Oxy-Fuel Conditions by Dry Sorbent Injection

Abstract

With increasing emphasis on the control of greenhouse gases, power plants may move towards oxy-fuel technologies rather than air-fired plants. This move leads to a change in the feed to the desulfurization unit, which also needs to be adapted along with the power plant. Most existing plants already have functioning desulfurization units, which need to be retrofitted for the new conditions. In the present study, three different limes have been examined as sorbents for sulfur capture in oxy-fuel conditions with varying residence times at medium temperature (150–450 ∘ C). Parameters indicative of the kinetics and competition between SO 2 and CO 2 , like SO 2 breakthrough time, total lime conversion, yield for sulfur capture and sulfur selectivity have been evaluated. The results of this study lead to the recommendation that medium temperature desulfurization should be used for moderate SO 2 capture, in combination with already existing sulfur capture systems. The effects of CO 2 and water vapor have also been analyzed. In addition, the performance of the unit irrespective of temperature strongly depends on the lime type. In addition, absence of water vapor strongly favored the desulfurization process when there was high concentration of CO 2 .

Experimental Study on Desulfurization Characteristics of Dry Sorbent Injection at Low SO2 Concentrations

“…The DSI technology uses dry injection and a distribution device to spray a high‐efficiency desulfurizer into the flue, where the desulfurizer is activated. With full contact of the desulfurizer with the flue gas, chemical reactions are carried out [6]. Acidic substances such as SO 2 in the flue gas are absorbed and removed.…”

Study on Spray Evaporation Treatment of Desulfurization Wastewater

“…Coal-fired power plants are facing the most stringent pollution discharge policy nowadays [1,2]. The limestone-gypsum wet flue gas desulfurization (WFGD) process is the most widely used technology in flue gas desulfurization (FGD) systems and often requires a significant amount of water for the scrubbing and dissolution process [3,4]. In order to control the amount of chlorine and fluoride ions in the scrubbing slurry and avoid material corrosion of the desulfurization system, part of the slurry must be periodically discharged as desulfurization wastewater.…”