农林废弃物干法消化系统中传质传热机理及关键基础

The resistances of mass transfer and heat transfer are high because of the high total solids in dry anaerobic digestion system of agricultural and horticultural wastes which leads to low biogas yield and poor process stability. Therefore, mass transfer and heat transfer are two key points in dry anaerobic digestion process. This project is intended to study the key scientific points and investigate the intensification methods and theory of the mass transfer and heat transfer in dry anaerobic digestion system. The velocity of mass transfer and heat transfer, distributions of mass and heat in porous structure will be measured with rapid transit technology. The influences of transfer medium on the surface structure, activity of microorganism and on the microbial community will be thoroughly investigated. The relationship of medium and mass transfer will be discovered and the fermentation kinetics will be studied. Considering the collision of particles and collision model, a theoretical model on the mass transfer and heat transfer of solid particles, gases and inoculum will be established using Direct Simulation Monte Carlo (DSMC) method. The mass transfer and heat transfer between particle and gas, inter-particles will be established and their intensification mechanism will be discovered. Mass concentration and heat distribution will be studied and their influence factors and regulation will be investigated. The key fundamental questions on mass transfer and heat transfer will be deeply investigated, which can lay solid foundation for industrial application of dry digestion.

干法消化系统的总固体含量高，传质和传热阻力大，导致中间产物易积累和反应不稳定问题，传质和传热是影响干法消化性能的关键。本项目拟以农林废弃物为底物，在半连续干法消化反应器中，研究废弃物床层传质传热行为，探索传质传热强化方法和理论。采用快速瞬态测试技术观测废弃物纳微孔道结构和颗粒间隙的传质和传热、瞬态温度与物质分布。研究传递介质的性质和种类对废弃物颗粒表面性质、微生物活性和菌群组成的影响，研究生物代谢反应动力学，建立代谢动力学模型，考察代谢动力学与传质的关系，揭示其动力学的控制因素。利用格子玻尔兹曼模型研究代谢产物和中间产物在颗粒孔道内部的传递以及热量的传递规律；综合考虑颗粒碰撞和生物代谢过程，利用蒙特卡洛方法建立颗粒与气体、颗粒之间的传热和传质行为的数学模型，深入研究传质传热机理及过程强化方法。本项目将对干法消化体系中传质和传热的关键基础问题进行深入研究，为产业化应用提供科学依据。

干法消化系统中总固体含量高，导致传质和传热阻力大、中间产物易积累、反应不稳定，传质和传热是影响干法消化转化效率和工艺稳定性的关键。本项目以农林废弃物为底物，在可搅拌半连续干法消化反应器中，研究了废弃物床层传质传热行为，探究了传质传热强化方法和理论。研究了传递介质的性质和种类对废弃物颗粒表面性质、微生物活性和菌群组成的影响，建立了农业废弃物代谢动力学模型，建立了代谢动力学与传质性能的关系。利用格子玻尔兹曼模型研究了搅拌杆外形、搅拌速度对代谢产物和中间产物的种类及其在颗粒孔道内部的传递以及热量的传递规律，深入研究了传质传热机理及过程强化方法；开展了厌氧消化过程中机器学习的应用并综述了最新的研究进展。本项目将对干法消化体系中传质和传热的关键基础问题进行深入研究，为产业化应用提供科学依据。