Sewage sludge ashes as a primary catalyst for the abatement of tar in biomass gasification: Bubbling versus spouted‐fluidized bed configuration

Abstract

Sewage sludge (SS) ashes, rich in iron and calcium, have been tested as a primary catalyst during air gasification of commercial wood pellets in a pre‐pilot scale fluidized bed (FB) reactor. The shifting from a conventional fluidized bed to a spouted‐fluidized bed configuration has been assessed on the catalyst performance. Specifically, at constant total air inlet flow rate, two different values of the air flow rate in a central spouting nozzle have been adopted, which correspond to 20% and 37.5% of the total inlet gas flow rate. Under the conventional fluidized bed configuration (i.e., bubbling regime), SS ashes exhibit good performance in term of tar reduction (about 20% decrease compared to a bed of inert silica sand), without significantly affecting the syngas composition. Concerning the transition to the spouted‐fluid bed configuration, the gas‐solid contact efficiency is enhanced at lower air flow rates through the central nozzle, with respect to the FB regime, leading to better gasification performance in terms of tar reduction (around 40% less) and syngas quality. A slightly worse gasification performance is obtained at high values of air flow rate in the central nozzle, due to a progressive increase of gas bed bypassing. Furthermore, moving from the conventional FB configuration to the spouted‐fluid bed one dramatically boosts the elutriation rate of carbon fines as well as the attrition of catalyst particles.

A comprehensive review of primary strategies for tar removal in biomass gasification

“…These catalysts may be used as primary catalysts directly in the gasifier, or as secondary catalysts in downstream catalytic processes. The use of in situ primary catalysts is a promising method to reduce the tar concentration in comparison with the use of a more expensive secondary catalytic cracking reactor downstream [58,242,243]. A large number of materials with significant activity for tar cracking and reforming have been examined as primary catalysts.…”

Special issue in honour of Professor Jamal Chaouki

“…99, issue 12) with 12 papers as Part II. [17][18][19][20][21][22][23][24][25][26][27][28] The special issue and special section cover experiments, modelling and simulation of multiphase reactors, pyrolysis and gasification, mineral processing, and applied catalysis.We would like to take this opportunity to thank all the contributors, reviewers, Dr. João B. P. Soares, and Kyra Van Den Bos, who, as the Managing Editor for this special issue, led the support team, which includes Tiffany Noel, Production Editor, and Lisa Olsen, Editorial Coordinator, in the publishing process. Above all, on behalf of all the contributors, we would like to take this opportunity to express our gratitude to Dr. Chaouki for his decades of dedication to teaching, mentoring, research, and community services in Canada, Morocco, and worldwide, and wish him and his well-respected family all the best in the future.…”

“…99, issue 12) with 12 papers as Part II. [17][18][19][20][21][22][23][24][25][26][27][28] The special issue and special section cover experiments, modelling and simulation of multiphase reactors, pyrolysis and gasification, mineral processing, and applied catalysis.…”

A Numerical Simulation and Experimental Study of Fluidization Characteristics of a Bubbling Fluidized Bed in Biomass Gasification

“…Furthermore, the bed material of the fluidized bed particles has an important influence on the heat and mass transfer [35][36][37]. And a large amount of material was used as fluidized bed particles to assist in biomass gasification.…”