article · Scientific Reports
Research investigated the production of solid fuel briquettes combining subbituminous coal and torrefied biomass bound with bentonite clay. A mixture of ninety-five percent coal and five percent biomass was compacted with varying proportions of bentonite, between two and ten percent, under high pressure and thermally cured under inert conditions. Testing showed that adding bentonite increased the density of the briquettes and provided strong mechanical durability through oxygen and silica bridges. However, higher bentonite concentrations reduced water resistance, fixed carbon, and overall calorific values. Briquettes prepared with two percent bentonite achieved the best balance, maintaining high mechanical strength without significantly compromising energy content. These findings demonstrate that low concentrations of bentonite effectively bind blended coal and torrefied biomass into resilient fuel blocks suitable for industrial thermal uses.
Blending coal with renewable torrefied biomass reduces reliance on pure fossil fuels, but composite solid fuels often crumble during handling and transport. Utilising a small proportion of bentonite clay as an inorganic binder produces durable briquettes that resist physical impact while maintaining high energy yields, offering a practical method to improve fuel handling for industrial processes.
The briquettes are recommended as feedstock for thermal and metallurgical applications, which could interest heavy industrial facilities and energy producers seeking sturdier composite solid fuels. The study represents applied laboratory testing, having evaluated physical durability, combustion properties, and microstructural bonding under controlled experimental conditions. Moving towards commercial adoption would require scaling production beyond laboratory hydraulic presses and assessing performance in operational industrial furnaces.
AI-generated from the published abstract. Always read the original work before citing.
Abstract The use of inorganic binder for briquetting of subbituminous coal and torrefied biomass for energy generation is scarce. The present study focuses on the physicomechanical durability and energy content of briquettes produced from subbituminous coal (SubC) and torrefied biomass (TM) using bentonite as binder. Briquettes were produced using 95% SubC and 5% TM. Bentonite was varied at 2–10% of the total SubC and TM weight. The briquettes were produced with a constant pressure (28 MPa) in a hydraulic press. The briquettes were primarily cured at room temperature and then at 300 $$^\circ{\rm C}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow/> <mml:mo>∘</mml:mo> </mml:msup> <mml:mi>C</mml:mi> </mml:mrow> </mml:math> in a tubular furnace under an inert condition for 60 min. The density and water resistance (WRI) of the briquettes were evaluated. Drop to fracture (DF), impact resistance index (IRI), cold crushing strength (CCS) and tumbling strength index (TSI +3 mm ) of the briquette were obtained. The reactivity index (RI), proximate, ultimate and calorific values analyses were assessed based on different ASTM standards. Microstructural studies and elemental mapping were carried out using scanning electron microscope equipped with EDS and electron probe microanalyzer. The density increased with increment in bentonite content. The WRI decreased with increase in bentonite while the least (95.21%) was obtained at 10% binder content. The DF and IRI ranges from 100 to 150 and 2000–3000, respectively. The CCS were in the range of 19.71 to 40.23 MPa. The RI varies from 34 to 50%. Fixed carbon, carbon and calorific values were impaired as the bentonite content in the briquette increases. Oxygen and silica bridges with mechanical interlocking were observed on the micrographs of the briquettes. The briquettes produced with 2% bentonite content have better physicomechanical durability with equivalent energy content. It is recommended as feedstock for thermal and metallurgical applications.
This page summarises published work. The authoritative version sits with the publisher.
DOI: 10.1038/s41598-022-12685-5
Is something wrong with this record? Report it or request removal.
Discussion
Have you built on this work, tried to replicate it, or seen it applied in practice? Share what you know. Verified researchers and MARATTO™ domain experts can open a discussion, and any member can reply. Contributions are reviewed before they appear.
No discussion yet. Open the first thread.
New to MARATTO™? Create a free account.
