Development and energy potential of co-firing fuel from blends of several biomasses and low rank coal at optimal condition

Abstract

Briquette making business is not widely popular in Northern Nigeria, even though it plays a vital role in enhancing the efficient use of solid fuels in the region. The study aimed to produce bio-coal briquettes from low-rank coal and several biomasses under optimal conditions. Briquette produced using a manually operated briquetting machine was tested to evaluate the impact of the briquettes’ combustion and physicochemical properties with respect to coal-biomass variation ratio, gasification temperature and compressive strength. Based on the experimental data, mathematical models were developed to predict the gross caloric value, ash content, moisture content, and relaxed density. To streamline repetitive tasks and lower experimental costs, Design Expert software was used to refine and optimize the briquetting process. Results of the study effectively revealed the impact of each dependent variable on achieving optimal bio-coal briquette production. The optimized results indicated that the calorific value increased from (27.10 to 27.74) MJ/kg, while the volatile matter content rose from (41.4 to 47.94) % by weight. Ash content and moisture content were reduced from (7.31 to 6.35) % and (11.9 to 9.8) % by weight respectively, while relaxed density and compressive strength were adjusted to meet target ranges of (0.8 to 1.09) KN/m² to (0.9 to 1.99) m³/Kg respectively.The newly produced bio-coal briquette represents an improved, environmentally friendly solid fuel that can be effectively used in any type of charcoal stove.