Recent developments in dry hot syngas cleaning processes

Upgrading of Raw Gas from Biomass and Waste Gasification: Challenges and Opportunities

“…However, it is a challenge considering the corrosion and material fatigue problems occurring at high temperatures with gases containing sulphur, chlorine and alkaline compounds. Consequently, gas impurities need to be removed prior to filtration or alternatively novel methods for dust cake removal have to be introduced [46,47]. The effects of poisons and trace impurities need to be examined more in depth.…”

“…Additionally, the forced reverse cleaning also result in a minor penetration of fine particles and impurities through the filter since the dust cake where the efficient filtration occurs is removed. To improve the lifetime of traditional candle filters and possibly also increase the operational temperature, sorbents to remove impurities, such as alkalis, chlorine and sulphur, to favourable concentrations could be applied [47]. This would reduce the risks for weakening by high temperature corrosion.…”

“…Alkalis could be removed in fixed beds with sorbents, such as, bentonites or bauxites [48,49]. Sulphur and chlorine by adding sorbents, such as CaO [47], to be removed as CaS and CaCl 2 either in a fixed bed or a cyclone, upstream the particulate candle filter.…”

“…A promising example to overcome the limitations present in traditional high temperature ceramic candle filters is filtration, based on a novel pulse less filter technology, proposed by Sharma et al [47]. The novel concept shown in Fig.…”

“…Sharma et al [47], also mentioned the possibility to integrate catalytically active filter elements in pulse less filters, combining a durable filter concept with tar cracking abilities at higher temperatures than possible today.…”