Tumbling strength and reactivity characteristics of hybrid fuel briquette of coal and biomass wastes blends

Abstract

This paper presents an assessment of the tumbling strength and reactivity behaviour of hybrid fuel briquette (HFB) produced from coal and torrefied woody biomass wastes. Briquettes were produced using 97% coal and 3% torrefied biomass with the blend of pitch and molasses in different ratios as a binder. The briquettes were treated in an inert environment at 200–300 °C for a residence time of 60 and 120 min in a tubular furnace. Fourier Transform Infrared Spectrophotometer (FTIR) was used to obtain the functional groups in the raw materials and the HFB. HFB were exposed to tumbling test (TSI+3mm) after curing and high temperature (1200 °C) exposure. Reactivity test (RI) of the HFB was carried out based on ASTM D5341M-14 standard. The FTIR spectra of the HFB show the presence of aromatic CC bonds and phenolic OH group. The TSI+3mm of the HFB samples drastically reduced from 95.5–98.3% for the treated to 57.4–77.4% for the samples exposed to 1200 °C. The reactivity indices of the HFB were in the range of 48–56%, which indicated that the HFB were highly reactive. Based on the TSI+3mm and RI, the HFB are suitable carbonaceous material in direct reduced iron making through rotary kiln.