三种能源草厌氧发酵制备生物燃气初步研究

摘要

The three kinds of energy grasses: Pennisetum purpureu, Miscanthus sinensis and Miscanthus floridulus from the Southchina area were conducted for biogas by using batch anaerobic digestion technical process at mesophilic temperature (35 ± 1oC), in this paper. The experiment results showed that the three kinds of energy grasses had different anaerobic fermentation performances:the highest daily biogas production were 31.33, 24.84 and 19.51 Nml·(gVSadded)−1·d−1, the cumulative biogas production were 355.78, 285.58 and 235.38 Nml·(gVSadded)−1, and the cumulative CH4 production were 166.43, 109.89 and 97.20 Nml·(gVSadded)−1, accounted for 33.83%, 21.67% and 19.48% of the theoretical CH4 production, respectively. Biogas yield of Pennisetum purpureu was obviously higher than that of the others, which was mainly because it had higher content of easily biodegradable organics. Modified Gompertz equation could be used well to fit the anaerobic digestion process of energy grass producing biogas. The simulation results were that the cumulative biogas production of the three kinds of grasses were 344.81, 290.11 and 279.01 Nml·(gVSadded)−1, and the delay times of anaerobic digestion tests were 5.96, 0.71 and 0 d.%以华南地区生长的多年生草本植物象草、芒草和五节芒为原料，采用序批式中温（35±1℃）厌氧发酵工艺，研究这三种能源草制备生物燃气的性能。结果表明：象草、芒草和五节芒的最高日产气率分别为31.33、24.84和19.51 Nml·(gVSadded)−1·d−1，原料产气率分别为355.78、285.58和235.38 Nml·(gVSadded)−1，产甲烷率分别为166.43、109.89和97.20 Nml·(gVSadded)−1，占理论产甲烷率的33.83%、21.67%和19.48%，象草的厌氧发酵性能优于芒草和五节芒的主要原因是象草中纤维素、半纤维素等易降解的有机物含量较高。修正的Gompertz方程拟合效果较好，象草、芒草和五节芒的累积产气量分别为344.81、290.11和279.01 Nml·(gVSadded)−1，延滞期分别为5.96、0.71和0 d。