Granular Bed Filtration of Coal Pyrolysis Gas: Effects of Media Reactivity on Dust Removal and Products

ABSTRACT

Granular bed filtration is a promising technology for removing dust from high‐temperature coal pyrolysis gas. In this work, the reactivity of coal pyrolysis products over ceramsite, char, ultrastable Y‐type (USY) zeolite, and quartz particles was compared. Based on laboratory results, a moving granular bed filter was designed and integrated into a 10 t·day ⁻¹ pilot‐scale coal pyrolysis facility to evaluate filtration performance and product changes. This work quantitatively decouples the physical dust‐removal effect from the catalytic secondary‐cracking effects of different filtration media at the pilot scale, establishing a baseline for isolating chemical effects and offering a practical criterion for media selection. Filtration reduced tar yield while increasing gas yield, with media‐specific effects. Ceramsite exhibited limited cracking activity, preserving tar yield at 91.56% of that with quartz, while enriching phenolics and aromatics, and boosting CH₄ and H ₂ yields. In contrast, char and USY zeolite demonstrated strong cracking activity, reducing tar yields to 82.96% and 62.37% of quartz levels, respectively, with decreased phenolics and oxygenates, and significantly increased yields of CH₄, H ₂ , CO ₂ , and CO. Pilot‐scale tests using ceramsite achieved a collection efficiency of 97% and an average pressure drop of approximately 500 Pa. After filtration, tar yield decreased from 5.20% to 4.20%, whereas gas yield rose from 9.24% to 9.94%. Tar composition shifted toward aliphatic and polycyclic aromatic hydrocarbons and away from monocyclic aromatics, with no significant change in gas composition. These findings provide critical insights for optimizing granular bed filtration in coal pyrolysis processes.