城市生活垃圾填埋气发电内燃机余热梯级利用分布式冷热电联供技术的基础研究

Aiming to improve the overall efficiency of the municipal solid waste landfill gas fueled internal combustion engine power generation system, the project suggests cascade utilization of waste heat of the landfill gas fueled internal combustion engine to achieve CCHP，the CCHP system utilizes flue gas waste heat of the internal combustion engine to drive high temperature and low temperature two-stage ORC for power generation, utilizes waste heat of lubricant, cylinder jacket and compressed air for heating, supplying sanitary hot water or driving LiBr absorption chillers to supply cooling water. The system utilizes Zeotropic Mixture Working Fluid as ORC's working fluid, and adds nanoparticles into Mixture Working Fluid to form Nano-mixture fluid to enhance heat transfer, utilizes heat pipe heat exchanger using Nanofluid as working fluid to achieve pure counter-flow pattern during heat transfer process, thus, to reduce exergy losses. Through the researches on the characteristics of waste heat released from the landfill gas fueled internal combustion engine,the physical and chemical properties of Mixture Working Fluids, the performances of ORC system, the regularities of Mixture Working Fluid's heat transfer process and the mechanism of heat transfer enhancement of nanoparticles,and the researches on the regularities of heat transfer and flow process inside main thermal units or subsytems, the thermodynamic methodology to select the best matching components and the best make-up ratio to form the ORC's Mixture Working Fluid, also the methodology to select the best working fluid for heat pipe will be established; the optimal design methodology of the landfill gas fueled internal combustion engine flue gas driven ORC using Zeotropic Mixture and its efficiently enhanced heat transfer equipments can be obtained;the optimal design theory and methodology to achieve disributed CCHP through cascade utilization of waste heat released by municipal solid waste landfill gas fueled internal combustion engine can inevitably be constructed.

为了提高城市生活垃圾填埋气内燃机发电系统综合效率，本项目提出梯级利用填埋气内燃机余热实现分布式冷热电联供，即用内燃机排烟余热驱动高低温两级ORC发电，用润滑油、气缸水套及压气机出口压缩空气余热供暖、供应生活热水或驱动溴化锂吸收式制冷机供冷。用非共沸混合工质作ORC循环工质，在混合工质里添加纳米粒子成纳米混合工质强化传热，用纳米工质热管换热器使冷热流体间逼近纯逆流换热，减少（火用）损。通过研究填埋气内燃机余热特性、混合工质物化性质、ORC系统性能、混合工质传热规律、纳米粒子强化传热机理及系统主要热力单元传热与流动规律，形成城市生活垃圾填埋气内燃机烟气余热驱动ORC混合工质的组元匹配与配比优化热力学方法、热管工质优选方法；获得填埋气内燃机烟气余热驱动混合工质ORC循环/换热设备的优化设计方法及强化传热技术；构建城市生活垃圾填埋气发电内燃机余热梯级利用分布式冷热电联供系统的优化设计理论和方法。

项目执行期间，按照计划书要求对城市生活垃圾填埋气发电内燃机余热梯级利用分布式冷热电联供方面作了深入研究，完成了相关理论体系的建立。研究了城市生活垃圾填埋气内燃机余热特性以及内燃机排烟余热驱动高低温两级ORC发电，用润滑油、气缸水套及压气机出口压缩空气余热供暖、供应生活热水或驱动溴化锂吸收式制冷机供冷过程，并分析了内燃机热力过程ORC系统性能及排烟余热物性及其所具有的能量；研究了以非共沸混合工质作ORC循环工质并在其中添加纳米粒子强化传热，并研究了用纳米工质热管换热器使冷热流体间逼近纯逆流的换热以减少㶲损；并通过研究填埋气内燃机余热梯级利用系统中混合工质物化性质混合工质传热规律、纳米粒子强化传热机理及系统主要热力单元传热与流动规律，形成城市生活垃圾填埋气内燃机烟气余热驱动ORC混合工质的组元匹配与配比优化热力学方法、热管工质优选方法。从而获得填埋气内燃机烟气余热驱动混合工质ORC循环/换热设备的优化设计方法及强化传热技术。基于以上研究，建立了城市生活垃圾填埋气发电内燃机余热梯级利用分布式冷热电联供系统及其优化的理论体系。