Sustainability analysis of dry treatment technologies for acid gas removal in waste-to-energy plants

摘要

Emission control from waste-to-energy plants asks for flue gas cleaning technologies for the removal of acid gases (mostly, HCI and SO2). Single stage dry injection of sodium bicarbonate is currently one of the most widely used among the best available techniques identified by the Industrial Emissions Directive in Europe, but several new waste-to-energy plants are implementing two-stage systems, coupling the injection of bicarbonate with a preliminary injection of calcium hydroxide. The present study aims at a comparative analysis of the environmental and economic viability of alternative dry treatment technologies. A life cycle perspective is adopted, encompassing production, transportation and disposal of the main reactants and products of the treatments. The optimal operating conditions for the two-stage system are identified and compared with single stage benchmark options. The two-stage treatment emerged as a flexible solution, which can couple cost-effectiveness and environmental compatibility. This performance was confirmed also under reasonable variations of factors such as waste composition, emission limit values and uncertainties in the input data. (C) 2017 Elsevier Ltd. All rights reserved.