有机垃圾组分种群增长及修正一级产气动力学研究

Population growth and the modified first order kinetics for biogas yield from each component of organic waste

以米饭、鸡蛋清、生菜、肥肉馅为原料,分别代表淀粉、蛋白质、纤维素、脂肪进行厌氧消化产沼气实验,并用种群增长模型和修正一级产气模型进行拟合.结果表明:脂肪的厌氧消化过程用修正Gompertz方程拟合效果较好,其余物料用Logistic方程拟合效果较好;脂肪的延滞期最长,为13 d,其次是蛋白质、纤维素,其值分别为8.72 d、6.24 d,淀粉的延滞期接近零.同时,建立了修正一级产气模型,并在延滞期之后用其模拟4种有机物厌氧消化产气过程,发现淀粉水解过程更趋向于遵循圆柱形颗粒模型,蛋白质、纤维素和脂肪水解过程更趋向于片状颗粒模型,淀粉和蛋白质的水解产气速度较快,脂肪稍慢,纤维素最慢;在延滞期内蛋白质和纤维素累积沼气产率都遵循零级水解动力学,脂肪的累积沼气产率遵循三次函数模型.在综合分析的基础上,得到了整个实验周期的产气动力学模型.

Batch anaerobic digestion was conducted for rice, egg white, lettuce, fat meat stuffing which stranded for starch, protein, cellulose and fat at 37 ℃. Population growth and modified first order kinetics model were used to simulate the biogas yield. The results showMedified Gompertz model better fits the experimental data for fat, compared with the Logistic equation; the biogas yield of starch, protein, cellulose preferred to follow the Logistic equation. Fat had the longest lag phase time of 13 days, followed by protein and cellulose with the lag phase time of 8.72 and 6.24 days. Starch almost had no lag phase time. Modified first order kinetics model was established to simulate the process of biogas yield for four kinds of organics after the lag phase time. The experimental data and the results of curve fitting by models show that the hydrolysis of starch preferred to follow the model of cylindrical particulates, and the hydrolysis of other three components preferred to follow the model of plat particulates. Starches exhibited higher biogas yield rate than protein, fat and cellulose. Accumulated biogas yield followed zero order hydrolysis kinetics for protein and cellulose and cubic function model for fat within the lag phase time. Based on the comprehensive analysis, biogas yield kinetics model was obtained during the whole experimental period.