Experimental evaluation and net energy analysis of methane gas production through anaerobic digestion of jatropha press-cake and pig manure

• Main Author: Gonzaga, Jeremias A.
• Format: text
• Language: English
• Published: Animo Repository 2013
• Subjects: Swine—Manure; Biogas; Manure gases; Jatropha; Energy Systems; Mechanical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/4459; https://animorepository.dlsu.edu.ph/cgi/viewcontent.cgi?article=11297&context=etd_masteral
• Institution: De La Salle University

Anaerobic digestion is a widely-used technology in biogas production which converts biomass feedstock into a biogas a robust renewable fuel. In anaerobic digestion, not only renewable biogas is produced but at the same time a byproduct is generated which could address waste management and pollution control as well. Jatropha press-cake in particular is a byproduct of biodiesel production however, the use of it is not yet fully realized. In this study pig manure was used as the co-digestion material since it shows a high potential in biogas production and because of the likelihood of the Philippines to produce sufficiently large amount of it. The combination of jatropha press-cake and pig manure has not been explored in current literature which shows a potential area in biogas production. This study focused on the biogas production of jatropha press-cake in different mixing levels of pig manure in co-digestion with water dilution ratios of 1:4 and 1:3 in order to determine the best possible mixing ratio. The methane gas content of the substrates percent mixture ratios 80JPC:20PM & 90JPC:10PM (1:3 WDR) and 90JPC:10PM (1:4 WDR) were found to be 172.97, 158.77and 133.35 L/kg VSdestructed respectively. A net energy analysis was conducted in order to evaluate the energy generated from production of biogas. A comparative analysis was done with the thermal gasification. In the production of biogas, two scenarios were considered: 1) water supply is obtained from conventional system provider (private concessionaires) and 2) water supply is obtained from deep well that uses common small electric water pump. In scenario 1, the substrates mix 80JPC:20PM percent ratio with water dilution ratio of 1:3 the net energy produced was found to be 6,195.477 KJ/kg (VSdestructed). In scenario 2, substrates mix 80JPC:20PM percent ratio with water dilution ratio of 1:3 the net energy produced was found to be 6,197.267 KJ/kg (VSdestructed). Based on the net energy evaluation of thermally gasified jatropha press-cake, the net energy produced was calculated to be 16,490 KJ/kg (gasification eff. of 65.96 %) and 17,077.5 KJ/kg (gasification eff. of 68.31 %) respectively.