基于TG-FTIR技术的猪粪与稻草混合厌氧发酵产甲烷特性研究

Evaluation of methane production by anaerobic co-digestion of pig manure and rice straw based on TG-FTIR technology

采用全自动甲烷潜力测试系统(AMPTS)和热重红外联用技术(TG-FTIR),对中温(37℃)下猪粪和稻草按不同挥发性固体(VS)比例(1:0、0:1、2:1、1:1、1:2、1:3)混合发酵产甲烷特性进行分析。AMPTS测试结果表明:稻草和猪粪混合比例为1:1时,发酵协同作用最好,实际甲烷产量比理论值提高了9.78%。TG-FTIR分析表明:1:1发酵时,残渣TG总失重率为47.84%,明显低于其它实验组; DSC曲线在250—350℃和400—550℃有2个明显放热峰,且1:1时放热量最少,说明该比例下有机物消耗最多,底物利用性更好,发酵稳定性更高;FTIR分析表明发酵残渣燃烧释放气体主要为水汽、CO_2、NH_3和少量挥发酸; 200—350℃和400—550℃温区下CO_2的峰值差异说明发酵中易消化有机物大量降解,残渣中较难氧化的芳香族结构和木质纤维素比例增加,发酵稳定性提高。研究结果阐明了混合厌氧发酵技术在农业废弃物甲烷化利用中的应用潜力及TG-FTIR技术在发酵产气特性及底物稳定性分析中的作用。

The characteristics of methane production from mesophilic co-digestion of pig manure and rice straw at different VS ratios(1:0,0:1,2:1,1:1,1:2,1:3)were investigated by AMPTS and TG-FTIR.The results showed that the best synergistic effect of co-digestion was achieved under the mixing ratio of 1:1,with a 9.78%increases of methane yield occurred compared to the theoretical value.The TG-FTIR analysis showed that the total weight loss rate of residue was 47.84%at the mixing ratio of 1:1,and was significantly lower than other experimental groups.The DSC curves from co-digestion digestates showed two exothermic peaks at 250-350℃and 400-550℃,respectively.The lower intensity of exothermic peak correlated with smaller amounts of organic matter undergoing oxidation,indicated that a better substrate utilization and a higher co-digestion stability were achieved under the 1:1 mixing ratio.The FTIR analysis results showed that release gas was mainly composed of water vapor,CO2,NH3 and a small amount of volatile acid.The difference of intensity of CO2 peaks between temperature area of 200-350℃and 400-550℃indicated an obvious degradation of digestible organic matters and an increased proportion of aromatic structure and lignocellulose residue,and the co-digestion stability was improved.The results indicated the application potential of anaerobic co-digestion in methane utilization of agricultural wastes and the role of TG-FTIR technology in analyzing gas production characteristics and substrate stability.