Mini-Review on Hot Gas Filtration in Biomass Gasification: Focusing on Ceramic Filter Candles

Abstract

Biomass gasification is increasingly attracting interest in the research of biorenewable energy all over the world, as a carbon-neutral supplement to the conventional fossil energy. It can convert biomass to the burnable producer gas for heat and power production or synthesis of fuels and chemicals. However, its commercial applications are seriously interfered by the minor but unavoidable contaminants or impurities in the raw product gas, which cause severe problems in the downstream equipment. This paper reviews the recent progress on the hot gas filtration technologies for removing particulate matters (PMs) and tars from the biomass-derived product gas, focusing on ceramic filter candles, which are widely applied in the biomass gasification systems. Developments of PM characterization, hot gas catalytic filtration, and oxidative filtration as well as the numerical simulation of computational fluid dynamics in hot gas filtration are summarized in detail. It also critically discusses the major challenges and future opportunities in hot gas filtration and concludes that the combined oxidative filtration and catalytic filtration with highly efficient catalyst at moderate temperatures (<600 °C) should be the most economical option for the widespread commercial small-scale biomass gasification systems.

Towards Biomass Gasification Enhanced by Structured Iron-Based Catalysts

“…Therefore, it would be necessary to filter the gas coming from the gasifier before their entry into the secondary reactor. Hot gas particulate cleanup is one of the most important improvements to commercial applications of biomass and coal gasification in the past 30 years [11]. This operation should then be carried out with filtering systems operating at high temperatures (400-550 • C), which themselves can face clogging/deactivation problems by the coke that can form as a result of any cracking reactions of the tar contained in the gas stream to be filtered [12,13].…”