Softwood and solid recovered fuel gasification residual chars as sorbents for flue gas mercury capture

Abstract

The scope of this paper is focused on gasification char (GC) utilisation as a direct sorbent for mercury capture from coal combustion flue gas. GC, being a waste material from thermochemical conversion, can represent an economically feasible variation of active coal-based sorbent. The aim of this study is to determine the absorption capacities of GC produced from softwood pellets (SWP) and solid recovered fuel (SRF). The influence of particle size and hot steam activation was examined. The carbon content in produced GC was between 73.7 and 93.4% wt., and SBET parameter up to 737.2 m2middotg-1. The Hg removal efficiency eta Hg was determined by a continuous mercury monitoring system. Promising removal efficiency results were obtained in the case of 0.5-2 mm particle size, hot-steam activated with 76.5 and 62.3% for SWP and SRF GC material, respectively. The results clearly suggest a promising, unconventional approach to waste utilisation in energetics, avoiding its inconvenient disposal. Thus, GC utilisation in the proper way may help to improve the sustainability of the circular economy on both small and big scales and, consequently, have a positive impact on various environmental aspects, such as air pollution control or extraction of resources minimalization.