Abstract:
Biodiesel and Briquetted Production from Spent Coffee Grounds (SCG) performed in laboratory scale and Response Surface Methodology (RSM) for compared observed results and predicted results. Central Composite Design (CCD) with less than 5% configuration error of 3 parameters was designed for this study. The results indicated that the highest %Yield of crude SCG oil (12.41%, R2 = 98.48) was found in the extracted condition of 35 kHz of Ultrasonic frequency, 5:1 of hexane as solvent/SCG, 65 C and 60 min. Gas Chromatography - Flame Ionization Detector (GC-FID) was applied for type and composition of fatty acid (FA) analysis. Mostly composition of FA in crude SCG oil were 43.71% Linoleic acid (C18:2) and 35.25% Palmitic acid (C16:0) with 5.18% free fatty acid. Biodiesel Production from crude SCG oil was synthesized under 2 steps processes; Esterification and Transesterification. The best condition for Biodiesel production (%FAME=77.87%, R2 = 88.82) was conducted under 18:1 of Methanol(mole)/SCG biofuel catalyzed with 0.15 N Potassium hydroxide for 60 min. SCG residue from biofuel extraction step was furnace for Briquetted. The best heating value (6,529 kcal/kg, R2 = 96.13) and density (0.4874 g/cm') of Briquetted occurred in the ratio of 10 SCG residue: 2 cassava starch: 20 waters with 30 kg/cm' of compressive strength. Total variable cost of SCG Biodiesel and Briquetted Production were 1,084.39 baht/kg and 7.32 baht/kg, respectively. It can summarize here that this research showed the alternative scenario for value added and waste utilization throughout the supply chain of coffee drinking business.