การผลิตถ่านชีวภาพภายใต้กระบวนการไพโรไลซิสจากสาหร่ายชุมชนร่วมกับผงกาแฟใช้แล้ว

Abstract

In this study, biochar yield and some properties such as higher heating value, pH, nitrogen content and BET surface area from co-pyrolysis of coffee ground (CG) and native microalgae consortium (NMC) of which the main population were Spirogyra Sp., Cladophora Sp., Microspora, and Rhizoclonium at various mass ratios were investigated. The biochar production was performed from the raw material at 150 g in a slow pyrolysis cylindrical fixed bed reactor at 5-10°C/min heating rate with 100 ml/min flow rate of nitrogen as sweeping gas. The reactor temperature was up to 400°C and the holding time was 1 h. Decrease of CG/NMC ratio gave higher percentage of biochar yield within a range of 43.5-45.5 %. The higher heating value of pure CG was rather high and suitable to be used as solid fuel but the value decreased with the increase in NMC composition. The pH value and nitrogen content in the biochar were found to be improved with the decrease of CG/NMC ratio. The pores generated in the co-pyrolyzed biochars were mesopores of which the specific surface area and the total pore volume increased with the NMC content then the biochars were suitable for soil amendment and taken as absorber to remove some toxic organic and inorganic pollutants in water and air treatments. Since the electrical conductivity of the biochar was higher with the increase of NMC content, the amount of the biochar having NMC composition for soil amendment should be carefully estimated to avoid high soil salinity and nutrient imbalances.