餐厨垃圾厌氧消化水解机理及动力学模型研究

The mechanism and kinetics of hydrolysis in the anaerobic digestion of kitchen wastes

对餐厨垃圾厌氧消化水解产物溶出规律进行了研究,证实扩散限制作用是导致水解速率出现滞后现象的主要原因.在考虑扩散作用影响的前提下,对餐厨垃圾水解机理作了必要补充阐述,并根据补充后的水解机理建立了餐厨垃圾水解分段动力学模型,并在模型中引入了扩散阻力系数.通过试验求得不同粒径(20mm、40mm、60mm)餐厨垃圾的扩散阻力系数分别为1.42、2.12、2.78.进一步分析表明,扩散阻力系数的变化基本符合指数函数规律,可将分段模型合并为统一的经验动力学模型.模型验证结果表明,预测值与实验值较为接近,能够描述餐厨垃圾的水解过程.

The profile of hydrolysates produced during the anaerobic digestion of kitchen wastes was investigated experimentally and theoretically. The experimental results showed that the hysteresis of the hydrolysis rate was mainly controlled by the diffusion effect. The hydrolytic mechanism of kitchen wastes is elaborated taking the diffusion effect into consideration. A partitioning model of the hydrolysis of kitchen waste is formulated including the coefficient of diffusion resistance in the model. The coefficients of diffusion resistance for different particle sizes （20mm,40mm, 60mm） are 1.42, 2.12, and 2.78 based on the experimental data, in which the coefficient of diffusion resistance vs. particle size conforms to an exponential function. So, the partitioning kinetic model could be integrated as a unified experience model. Verification of the model by comparison with the experimental data showed that the model could predict the concentration of organic substances during the anaerobic digestion of kitchen wastes.