Canarium schweinfurthii resin as an organic binder for carbonized briquettes

Abstract

Charcoal is the predominant fuel used in many developing countries for domestic and commercial purposes. Transport and handling of charcoal produces fines amounting to 10-20% by weight. The fines can be turned into lumps of charcoal by briquetting using suitable binders. This study investigated the use of Canarium Schweinfurthii resin as a binder for production of carbonized briquettes from charcoal fines. The binder and charcoal fines were characterized through proximate analysis, ultimate analysis, higher heating value (HHV), and SEM. Four briquette samples (B25, B30, B35, and B40) with a ratio of charcoal fines: binder of 3:1, 7:3, 13:7, and 3:2, respectively were produced at a compaction pressure of 5.92-7.96 MPa. The physical properties of briquettes determined were bulk density, impact resistance index (IRI), compressive strength (CS), splitting tensile strength (STS), water resistance index (WRI), and morphology. The chemical properties of briquettes determined were proximate analysis, ultimate analysis, HHV, and energy density. The physical properties of briquettes were analysed using Design Expert. One way ANOVA and Fisher’s LSD were used to analyse the chemical properties of briquettes. The phases of the Water Boiling Test (WBT) considered were Cold Start High Power, Hot Start High Power and Simmer phases. Ignition properties, combustion properties, gas temperature, water temperature, ambient temperature, emissions, and WBT performance metrics were investigated using the Laboratory Emission Monitoring System. The ignition properties included ignition time, flame and incandescence. The combustion properties included smoke, flame, soot, and ash. The emissions measured were PM2.5, S𝑂2, 𝑁𝑂𝑥, 𝐶𝑥𝐻𝑦, 𝐶𝑂, and 𝐶𝑂2. The WBT performance metrics evaluated were time to boil, burning rate, thermal efficiency, specific fuel consumption, firepower, total emissions, specific emissions, emissions per MJ, and emissions rate. The ash from charcoal fines was analysed using x-ray diffraction. The briquettes had a bulk density of 0.770-1.036 g/cm3 , IRI of 2.90-73.33, CS of 2.25-10.94 MPa, STS of 0.09-0.42 MPa, WRI of 99.26-99.29, and an HHV of 29.7-31.3 MJ/kg. The ignition time was 6.47-7.01 min, time to boil was 14.7-41.9 min, burning rate was 1.1-8.2 g/min, thermal efficiency was 21.79-54.61%, specific fuel consumption was 21.7-70.1 g/L, and firepower of 535.9-4123.2 W. The ash was found to contain 𝐶𝑎𝐶𝑂3 (76.6 wt%), 𝐶𝑎𝑂 (13.1 wt%) and amorphous compounds (10.3 wt%). Design Expert predicted briquette B40 with the optimum physical properties. The produced briquettes can be used as an alternative source of fuel to wood fuel since they exhibit similar combustion properties.