Review of Porous Ceramics for Hot Gas Cleanup of Biomass Syngas Using Catalytic Ceramic Filters to Produce Green Hydrogen/Fuels/Chemicals

Abstract

Biomass gasification is one of the most promising routes to produce green hydrogen, power, fuels, and chemicals, which has drawn much attention as the world moves away from fossil fuels. Syngas produced from gasification needs to go through an essential gas cleanup step for the removal of tars and particulates for further processing, which is one of the cost-inducing steps. Existing hot gas cleanup strategies involve the particulate removal step followed by catalytic tar reforming, which could be integrated into a single unit operation using porous ceramics owing to their advantages including high-temperature resistance, high corrosion resistance, flexibility, and robust mechanical integrity. Ceramic filters have proven to be effective at filtering particulates from hot gas streams in various applications including combustion, incineration, gasification, and pyrolysis. These materials have also been evaluated and used to an extent as catalyst support to remove contaminants such as nitrogen oxides (NOx), volatile organic compounds (VOC), and in particular, tars, however, the use of these ceramic materials to remove both tars and particulates in one unit has not received much attention, although it has a promising potential to be a cost-effective hot gas cleanup strategy. Thus, this review presents the ability of catalytic ceramic filters to boost energy efficiency by converting unwanted byproducts while simultaneously eliminating PM in a single unit and is shown to be valuable in industrial processes across the board. This article presents a comprehensive and systematic overview and current state of knowledge of the use of porous ceramics for catalytic hot gas filtration applications with an emphasis on biomass syngas cleanup. In addition, a similar strategy for other applications such as combustion exhaust streams is presented. Prospects and challenges of taking this approach, and the necessary research and development to advance the novel use of reactive ceramic filters within biomass-fed thermal systems are presented. Major challenges include the low surface area of the ceramic filter media and high-pressure drop across the filter media, which can be overcome by wash coating or dip coating mechanisms and porosity tailored to meet the requirements. Owing to limited R&D efforts in this area, a systematic approach toward developing these integrated hot gas filtration systems is much needed, which will ultimately contribute to cost-effective green hydrogen production.

The Bulk Density and Cohesion of Submicron Particles Emitted by a Residential Boiler When Burning Solid Fuels

“…The pores of the filter are, in most cases, significantly larger in size than the particles to be captured. The capture process requires the bridging of the particles in the initial stage of filtration, thus partially clogging the pores and increasing the filtration efficiency for the fine particles; see Figure 8 (adapted from [29,30]). On the other hand, particle cohesion can also have an undesirable effect, for example, when particles are captured in impactors.…”

“…Particles that are easy to bond permanently form narrow but relatively high structures (towers) on the impaction surface, which restrict the function of the impactor, even though the mass of the captured particles has not reached the desired value. [29,30]).…”

Advancing Sustainable Decomposition of Biomass Tar Model Compound: Machine Learning, Kinetic Modeling, and Experimental Investigation in a Non-Thermal Plasma Dielectric Barrier Discharge Reactor

“…Typically, producer gas consists of H 2 , CO, CO 2 , CH 4 , as well as other hydrocarbons, and N 2 if air is used as a gasifying agent [9][10][11][12]. Among the variety of hydrocarbons produced during gasification, one should distinguish tars, which are problematic in terms of downstream processing of the producer gas [13][14][15][16].…”