Development, properties and potential applications of high-energy fuel briquettes incorporating coal dust, biowastes and post-consumer plastics

Abstract

The conversion of waste to energy through briquetting has the potential for providing energy, while simultaneously reducing wastes and their environmental health risks. The current study developed and evaluated high-energy fuel briquettes from mixtures of coal dust, biowastes and postconsumer plastics. Five waste mix ratios (wt%) of coal dust (C), postconsumer plastics (P) and sawdust (S) were tested: (1) C50-40-S10, (2) C-60-P30-S10, (3) C70-P20-S10, (4) C-80-P20-S0 and (5) C-80A-P0-S20. Waste mix ratio had a significant effect (p < 0.05) on water absorption, shatter index, compressive strength and energy values, but had no effect on density. The densities (1.1-1.3 g/cm 3 ) and shatter indices (94-98%) of all briquettes conformed to international standard specifications for fuel briquettes, indicating that the briquettes had acceptable handling properties. A waste mixture ratio of 50% coal dust, 40% plastics and 10% sawdust (C50-P40-S10) produced a briquette with the best overall combination of handling and energy properties. The high-energy briquettes had calorific values of 26.5-33.8 MJ/kg, which were significantly higher than or comparable to the maximum values reported for high-energy coal (27 MJ/kg), while the compressive strength was 0.7 MPa. Potential applications of the briquettes include (1) household and institutional heating and cooking and (2) industrial heating in kilns, furnaces, smelters, curing and drying of crops (e.g., tobacco barns. Further work is required to address the following:(1) evaluation of the detailed physicochemical, combustion and emission properties, (2) optimization of the briquetting process, (3) cost estimation of the briquettes relative to existing competing solid fuels and (4) comparative performance evaluation of the briquettes versus conventional solid fuels in the various applications.

Characterisation of briquettes from forest wastes: Optimisation approach

“…The density of the briquette was found to have a mean value of 0.662 kg•m -3 with a range of 0.535 to 0.809 kg•m -3 at the corresponding mixing ratios of 25 : 75 and 100 : 0, while the quantity of the binder in each mixing ratio was 60 and 70 g, respectively. The optimum density of the briquette was found to be 0.70 kg•m -3 at a mixing ratio and binder quantity of 75 : 25 and 60 g. The values of the density are commensurate with what is obtainable in the literature (Prasityousila and Muenjina 2013;Gwenzi et al 2020;Olugbade and Ojo 2021). The variation in the mixing ratio and quantity of the binder in the briquette has a significant impact on the density of the briquette as depicted in Table 3.…”

“…The influence of the variation in the mixing proportion and quantity of the binder on the water resistance of the JSS-EcWS briquette was established; the water resistance of the briquette was found to have a mean value of 91.12% with a range of 72.04 to 97.45% at the corresponding mixing ratios of 25 : 75 and 75 : 25, while the quan- https://doi.org/10.17221/6/2021-RAE of 99.22 to 99.88% at the corresponding mixing ratios of 25 : 75 and 75 : 25, while the quantity of the binder in each mixing ratio was 60 g respectively. The optimum shatter index of the briquette was found to be 99.86% at a mixing ratio and binder quantity of 75 : 25 and 60 g. These values were above the recommended value of 90%, thus indicating the ability of the briquette to retain their form after being subjected to an impact force (Borowski 2007;Borowski and Hycnar 2013;Gwenzi et al 2020). The range obtained for the shatter index of the JSS-EcWS briquette is similar to that of a sawdust briquette blended with neem powder (Rajaseenivasan et al 2016) and a corn cob and oil palm trunk bark briquette .…”

Empirical Studies on Biomass Briquette Production: A Literature Review

“…Already the briquettes made up of 75% pine wood and 25% of other residues resulted in excellent properties of equilibrium moisture content (9-11% by weight), tensile strength (415-569 kgf), apparent density (1107-1163 kg•m −3 ) and energy density (19,,899 MJ•m −3 ). (%) [29] 100 [43] 65 [28] 10 * 90 [44] 10 [13] 75 100 [34] 75 [30] 90 [39] 50 * 100 [31] 90 [46] 100 * Optimal values indicated by the authors, [29] Corncobs (CC), [43] Cashew nut shells (CNS) and contain 10 to 20% of cassava flour, [28] Cornhusk (CH), [44] Sawdust (S), [13] Pine wood, [34] Sugar cane bagasse, [30] Date palm trunk biomass, [39] Charcoal fines, [31] Coke, [46] Coconut fiber (FC).…”

Climate Change, Water Quality and Water-Related Challenges: A Review with Focus on Pakistan

“…For instance, watershed management with dam systems might alleviate drought and floods. Developing effective treatment methods e.g., [ 172 , 173 , 174 ], for addressing the sixth United Nations sustainable development goal, which deals with fecal contamination (69% fecal pollution has been reported in 23 major cities) and provision of safe drinking water to the general public. Adaptation strategies such as protection of water resources and watershed management should be adopted to cope with unforeseen situations and to decrease the water-related disease burden.…”

“…Developing effective treatment methods e.g., [ 172 , 173 , 174 ], for addressing the sixth United Nations sustainable development goal, which deals with fecal contamination (69% fecal pollution has been reported in 23 major cities) and provision of safe drinking water to the general public.…”