Optimizing the mechanical properties of coal-fines briquettes produced with steam-exploded sugarcane bagasse as a binder

Co-briquetting of coal fines and lignocellulosic biomass is a possible path for incorporating biomass energy into the current coal-based infrastructure, although the cost and performance of conventional binders remain problematic. The use of steam-exploded sugarcane bagasse (SE SCB) as a binder for coal fines briquetting was therefore investigated. SE SCB (produced at 140-220 degrees C for 15 min) was mixed with high-ash bituminous coal-fines at various concentrations (0-18%), and briquetted at a pressure value of 24 MPa and at various temperatures (25-180 degrees C). Following multivariate optimization, an optimal steam explosion temperature range of 185-195 degrees C was found. At these pretreatment temperatures, sufficient disruption of the lignocellulosic structure occurred, resulting in increased binding between coal fines and SCB, while higher temperatures resulted in detrimental destruction of fiber structure and reduction in binding performance. A synergistic interaction between briquetting temperatures and SE SCB content above 100 degrees C and 13%, respectively, substantially improved briquette properties. At these optimum conditions, the briquettes had a compressive strength of 1205 kPa, an abrasion resistance of 97%, water absorption index of 82%, and a wet compressive strength of 501 kPa. Briquettes maintained structural integrity when pyrolyzed at 700 degrees C and had a post-pyrolysis compressive strength of 134 kPa, indicating that SE SCB could potentially be a suitable binder for coal fines briquetting.

Automated summary

Steam-exploded sugarcane bagasse (SE SCB) can be used as a binder for coal fines briquetting, with an optimum temperature range of 185-195 degrees Celsius. At these temperatures, the binding between coal fines and SCB is improved, but higher temperatures result in detrimental destruction of fiber structure and reduction in binding performance. Briquettes made under these optimal conditions have higher compressive strength and abrasion resistance, indicating that SE SCB could potentially be a suitable binder for coal fines briquetting.