Producing Methane Enriched Biogas using Solvent Absorption Method

Abstract

Waste-to-energy (WTE) production is one of the sustainable solutions to fulfill energy demands and minimize the environmental problems associated with waste landfilling. This work investigates the biogas production and methane (CH4) enrichment for anaerobic digestion (AD) of fruit and vegetable waste (FVW). The effect of pH and temperature were studied using a lab scale batch anaerobic digester. The raw biogas was pebbled through water, NaOH, Ca(OH)2 and triethanolamine (TEA) for biogas purification and CH4 enrichment. The results showed that mixed fruit waste (MFW) provides 10 % more biogas yield than mixed fruit vegetable waste (MFVW). The maximum biogas yield of 0.030 (g/g volatile solids) was achieved at thermophilic temperature (TT). The optimum pH range under mesophilic temperature (MT) and TT condition was in between 8.3 - 8.8. The use of NaOH, Ca(OH)2 and TEA increased CH4 enrichment upto 5 %, 9 % and 7 %. Biogas having 71 % CH4 contents with 28 % reduced CO2 and 150 ppm H2S was produced using Ca(OH)2.