【作者】 李洪强；

【导师】 金红光； 蔡睿贤；

【作者基本信息】 中国科学院研究生院（工程热物理研究所） ， 工程热物理， 2009， 博士

【摘要】 化工、动力和环境等领域与学科的交叉已经成为当代能源科学发展的趋势。寻求资源、能源高效利用的有效途径与方法，逐步成为人类可持续发展的重要问题之一。本学位论文依托国家自然科学基金及973项目等科研任务，研究单一能源输入以及多能源互补的多联产系统中的若干问题。主要包含以天然气重整为案例分析化学能梯级利用在化学反应过程中的应用，以及基于此提出的新型多联产系统开拓研究两个层面。从化学反应动力学结合化学热力学角度出发，建立了天然气重整过程所需要外界提供的时间能耗与反应进度之间的关系式；从吉布斯自由能前后变化角度出发，分析了重整过程吉布斯自由能的变化与反应进度之间的关系。计算与分析结果表明，当重整率比较高(＞0．6)时，单位天然气重整所需要的能耗和时间大幅增加，而吉布斯自由能将大幅降低，这将会导致单位天然气的平均重整代价骤然增加。这种现象普遍存在于其它很多基元反应非零次方的化学反应过程，可以将适度反应潜在节能拓延其应用范围到其它化工生产领域以及动力领域，通过耦合化工与动力两个生产过程，可以突破传统化工系统追求单一产品转化率所带来的单位产品高能耗的弊端，实现燃料化学能、物理能的综合梯级利用。研究提出天然气部分重整的甲醇动力串联型多联产系统。该系统的特点为：依据化学能梯级利用原则，该系统采用了天然气部分重整，降低单位合成气的生产能耗；根据“组分对口、分级转化”系统集成原则，将合成气中适合甲醇生产成分用于化工生产进行资源化利用，剩余成分作为动力系统燃料进行能量化利用。对此系统进行火用平衡分析表明系统的关键过程为重整过程和甲醇合成过程，并通过图像火用(EUD)分析揭示过程内部能量释放、交换以及蕴含的节能潜力。与分产系统进行性能比较，采用该多联产方式生产同样的甲醇和电力时，可以实现节能5-10个百分点。针对可再生能源中生物质能所特有的碳氢结构特点，提出了以生物质气化为龙头的甲醇动力串联型多联产系统。该系统将化工生产过程与热力过程有机结合起来，通过先资源化利用后能量化利用逐级释放生物质能，从而实现了生物质化学能、物理能的梯级利用。与生物质基甲醇分产与动力分产火用效率仅有44％和41％相比，该多联产系统通过调节未反应气的循环量，在输出化动比0．6-1．8之内，能够获得7％-10％的节能率以及44％-49％的系统火用效率。根据天然气资源和生物质能源二者不同碳氢比例成分特点，提出了天然气与生物质互补的甲醇动力串联型多联产系统(包含两种方案)。在该多联产系统中将天然气—水蒸气部分重整造气和生物质气化造气结合起来，通过纯物理混合的方式实现了甲醇合成气的最佳碳氢配比，并利用适度反应潜在的节能优势耦合了甲醇生产与电力生产过程。不但实现了天然气和生物质的碳氢组分互补，还实现了合成气化学能的梯级利用。对该多联产系统进行性能分析表明，在甲醇合成气一次性通过系统中，天然气与生物质的输入比在0．5-8范围内变化时，系统能够获得8-10％的节能率；在未反应气采取部分循环时，系统能获得9．5％上的节能率。更多还原

【Abstract】 Synthetically combining the power generation,the chemical production andenvironment protection is the trend and character of the development of energy science.Searching the effective methods to make good use of resources and energy has becomevery important for continuous development.Focusing on this objective,the main study ofthis dissertation proposes the novel polygeneration systems based on natural gas andbiomass individually and on both of them as co-feed.The work was supported by theNational Natural Science Foundation of China and the Hi-tech Research and DevelopmentProgram of China,the researches include the mechanism of natural reforming,which willreveal the cascaded utilization of chemical energy during the chemical reaction,and theproposal of the novel polygeneration systems based on that principle.From the viewpoint of chemical kinetics and thermodynamics,the relation formula ofthe energy and time consumption supplied by outside with the extend of reaction was setup;moreover,from the viewpoint of Gibbs free energy,the relation of the change of Gibbsfree energy and the extend of reaction was also analysied.The results of calculation andanalysis shown that,when the extend of reaction over 0.6,the energy and timeconsumption will grow rapidly,and at the same time,the Gibbs free energy will decreasevery quickly.That is to say,the costs for per mole methane reforming will grow very highwith a higher extend of reaction.The phenomenon is very common in many reactionswhose elementary reaction with nonzero capital,thus the mechanisms can be extended itsrange of application,such as the chemical industry and power field.Coupling the chemicalprocess and power generation,can reduce the high energy and time consumption of perproduct in traditional chemical process for purchasing very high conversion ratio of rawmaterials,and realize the cascaded utilization of fuel.A new polygeneration system based on natural gas partial reforming is proposed, which produces methanol and power with tandem type.The characters of this systemincludes:Based the principle of cascaded utilization of chemical energy,this systemadopts partial reforming of natural gas,which aims to reduce the energy consumption forper mole syngas production;Based on the principle of cascade conversion of materialaccording to the compositions,a part of syngas that suites for chemical production is usedin the chemical process and the left is sent to gas turbine as fuel.By the analysis of systemexergy balance,found out that,the key processes are reforming process and methanolsynthesis process,more over,the EUD methodology is selected in order to reveal the innerenergy release,exchange and energy saving potential.Comparing with individual systems,this polygeneration system can realize 5-10% energy saving potential.According to thecomposition characters of biomass,a new polygeneration system based on biomassgasification is proposed,which produces methanol and power.This system coupled themethanol syntheis subsystem and power generation subsystem,so as to realize the cascadeutilization of the chemical energy in gasification gas.Comparing with the individualsystems,this polygeneration system can realize 7%-10% energy saving potential andobtain exergy efficiency between 44%-49%.The energy in biomass can be released stepby step in this system,which will bring the high effective utilization of bio energy.Taking into account of the different carbon and hydrogen ratio in natural gas andbiomass,a new polygeneration system with two schemes based on biomass and naturalgas as co-feed is presented here.By coupling the partial reforming of natural gas andgasification of biomass to produce syngas,the best ratio of carbon to hydrogen formethanol production can be obtained easily without any energy penalty.More over,thissystem can realize not only the complementation of natural gas and biomass but also thecascaded utilization of syngas by coupling chemical process and power generation.Thesystem performance shown that,the system with the syngas once through scheme,cansave 8%-10% energy when the input ratio of natural gas to biomass range from 0.5 to 8;with the partial recycling of unreacted syngas scheme,the system can realize energysaving ratio at least 9.5%.更多还原