Aluminosilicate Clay Minerals: Kaolin, Bentonite, and Halloysite as Fuel Additives for Thermal Conversion of Biomass and Waste

Abstract

The current focus on renewable energy sources and the circular economy favors the thermal conversion of low-quality fuels, such as biomass and waste. However, the main limitation of their usability in the power sector is the risk of slagging, fouling, ash deposition, and high-temperature corrosion. These problems may be avoided or significantly mitigated by the application of aluminosilicate clay minerals as fuel additives. In this paper, the three most commonly occurring aluminosilicates are reviewed: kaolin, halloysite, and bentonite. Their application has been proven to minimize combustion-related problems by bonding alkalis in high-melting compounds, thus increasing ash melting temperatures, reducing ash deposition tendencies, and decreasing the particulate matter emission. Due to excellent sorption properties, aluminosilicates are also expected to fix heavy metals in ash and therefore decrease their emissions into the atmosphere. The application of aluminosilicates as fuel additives may be a key factor that increases the attractiveness of biomass and other low-quality fuels for the power sector.

Performance of Corn Cob Combustion in a Low-Temperature Fluidized Bed

“…of volatile alkaline elements in the fuel used. Research has shown that blending low-quality fuel with additives can lead to a decrease in the formation of solid particles and other combustion by-products, such as NOx, SO2, and HCl, during the combustion process [23].…”

“…Using additives and combined fuel aims to change the composition of the raw material and additionally reduce the share of volatile alkaline elements in the fuel used. Research has shown that blending low-quality fuel with additives can lead to a decrease in the formation of solid particles and other combustion by-products, such as NOx, SO 2 , and HCl, during the combustion process [23]. During gasification, dolomite undergoes calcination to yield CaO, which acts to prevent agglomeration by favoring the formation of K 2 CO 3 over K 2 OnSiO 2 [24].…”

Possibilities of RDF Pyrolysis Products Utilization in the Face of the Energy Crisis

“…(6) Continuous and intensive research on the pyrolysis process and the possibilities of managing its products enrich the world of science and bring the economy and industry closer to the introduction of pyrolysis for use on an industrial scale. (7) Finding new applications for pyrolysis products. Proposal to use pyrolysis gas and biochar for energy purposes, reducing the consumption of conventional fuels.…”

“…Improper management of MSW not only has a negative impact on the environment, but also poses a threat to public health and raises other socio-economic problems. Waste-to-energy (WtE) technologies such as pyrolysis, gasification, incineration and biomethanization [7] can convert MSW into usable energy (electricity and heat) in a safe and environmentally friendly way [8].…”

Synthesis and Characterization of Nanocomposite Hydrogels Based on Poly(Sodium 4-Styrene Sulfonate) under Very-High Concentration Regimen of Clays (Bentonite and Kaolinite)

“…Clays encompass a diverse group of natural minerals with layered structures, including montmorillonite, kaolinite, smectite, among others. The unique arrangement of layers provides clays with exceptional properties, such as high surface area, swelling capacity and ion exchange capacity [ 23 , 24 ]. Specifically, bentonite and kaolinite are two types of clays with significant differences in their chemical composition, crystal structure, and physicochemical properties, making them useful in the petroleum and gasification industry for the purposes of ceramic manufacturing and wastewater treatment [ 25 , 26 ].…”