Effects of lime pretreatment on biogas production from dry dairy cattle manure

Aim. The main goal of the current study was improvement of biogas production from cattle manure with Ca(OH)(2) pretreatment. Methods. Effects of temperature (20 degrees C and 60 degrees C), time (10 min, 2, and 12 h), and pH (9, 10, 11, and 12) on liming of the manure on biogas production was investigated. Cattle manure treated at different alkali conditions was subjected to anaerobic digestion and the methane produced during 45 days was measured. Results. The results showed that alkaline treatment at 20 degrees C did not affect the biogas production, while the manure treated at 60 degrees C produced more methane than the untreated one. The biogas production was increased by increasing the pH and treatment time. Maximum improvement in methane production was achieved by pretreatment at pH 12 for 12 h, and resulted in 225 ml CH4/g VS which was 76% higher than the methane yield obtained from untreated manure. The analysis of the treated and untreated manure showed that the alkali treatment eliminated 22.7% of the total lignin. Lignin removal may be the reason of improvement in digestibility of the manure and consequently the yield of biogas Conclusion. Lime pretreatment is a promising method for improvement of biogas production from cattle manure

Effects of lime pretreatment on biogas production from dry dairy cattle manure

Aim. The main goal of the current study was improvement of biogas production from cattle manure with Ca(OH)(2) pretreatment. Methods. Effects of temperature (20 degrees C and 60 degrees C), time (10 min, 2, and 12 h), and pH (9, 10, 11, and 12) on liming of the manure on biogas production was investigated. Cattle manure treated at different alkali conditions was subjected to anaerobic digestion and the methane produced during 45 days was measured. Results. The results showed that alkaline treatment at 20 degrees C did not affect the biogas production, while the manure treated at 60 degrees C produced more methane than the untreated one. The biogas production was increased by increasing the pH and treatment time. Maximum improvement in methane production was achieved by pretreatment at pH 12 for 12 h, and resulted in 225 ml CH4/g VS which was 76% higher than the methane yield obtained from untreated manure. The analysis of the treated and untreated manure showed that the alkali treatment eliminated 22.7% of the total lignin. Lignin removal may be the reason of improvement in digestibility of the manure and consequently the yield of biogas Conclusion. Lime pretreatment is a promising method for improvement of biogas production from cattle manure

Economic impact of NMMO pretreatment on ethanol and biogas production from pinewood

Processes for production of ethanol and biogas (scenario 1) and biomethane (scenario 2) frompinewood improved byN-methyl morpholine-N-oxide(NMMO)pretreatnmentweredeveloped and simulated by Aspen plus®.These processes were compared with twoprocesses using steam explosion instead ofN-methyl morpholine-N-oxide(NMMO)pretreatmentfor production of ethanol (scenario 3) and biomethane (scenario 4),and the economies of these four processes wereevaluated by Aspen Process EconomicAnalyzer (PEA).The gasoline equivalent prices of the products including25% value addedtax (VAT)andselling and distributionexpenses for the scenarios1 to 4were respectively1.40, 1.20, 1.24, and 1.04 €/l, whicharelower than gasoline price (1.65 €/l average in 2013 inSweden). Theprofitability indexesfor the scenarios 1 to 4 were1.14, 0.93, 1.16, and 0.96,respectively. Despitethelower manufacturing costs of biomethane, theprofitability indexesof these processes werelowerthan that of the bioethanol processes, because of higher capitalrequirements. Theresults showed thattaxing rule is an effective parameter on the economy ofthe biofuels. The gasoline equivalent prices ofthe biofuels were 18-39% lower than gasoline;however, 37% of the gasoline price contributes to energy and carbon dioxide taxwhich arenot included in the prices of biofuelsbased on the Swedish taxation rules