Alkali removal with mineral sorbents - Part I: Sorption capacity and reaction kinetics

Aluminosilicate sorbents show the potential to reduce alkali-related problems during solid fuel conversion such as deposit build-up and corrosion damages. The alkali capacity, the reaction kinetics and the surface area devel-opment of the sorbents under operating conditions are essential parameters for the mathematical description of the alkali sorption. In this work, three sorbents, kaolin, bauxite and bentonite, are characterized in this regard by thermogravimetric analysis. The sorption behavior of kaolin surpasses the other sorbents dueto the highest load-ing capacity and the temperature-stability of the porous structure. However, the suitability as sorbent in solid fuel conversion processes is given for all materials. A mathematical sorption model is applied to the experimental data in order to derive kinetic parameters of the sodium and potassium sorption under syngas and flue gas atmo-sphere. Thus, this work provides the necessary dataset for the design and optimization of the sorbent use in in-dustrial processes. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Aluminosilicate sorbents have the potential to reduce alkali-related problems in solid fuel conversion, such as deposit build-up and corrosion damages. This study characterized three sorbents and found that kaolin has the highest loading capacity and temperature stability of the porous structure, making it superior in alkali sorption. However, all materials are suitable for use as sorbents in solid fuel conversion processes.