基于生物质—水蒸气气化的冷热电联供系统研究

发布时间：2018-08-06 12:06

【摘要】：当前能源短缺、环境污染等问题十分严重,可再生能源的利用比例不断上升。生物质能作为一种可再生能源,资源丰富,污染小,已成为许多国家的重要战略选择。本文基于生物质-水蒸气气化的方法,将其与冷热电联供系统集成,提出了一种合理利用生物质能源的方法。首先,本文提出了两种生物质-水蒸气气化的冷热电联供集成系统,分别通过燃烧生物质气和利用电加热来提供生物质气化所需要的热量。集成系统采用热管式气-液换热器对生物质气的余热进行回收利用来制取气化反应所需要的水蒸气,不再借助于其他蒸汽发生装置,实现了能量的梯级利用。建立了生物质-水蒸气气化两个子系统和冷热电联供子系统的热力学数学模型,并进行了相应的验证。。其次,给出了生物质-水蒸气气化冷热电系统三种不同的运行工况:夏季工况、冬季工况和过渡季工况。以北京市某宾馆的冷热电负荷为例,基于热力学第一、第二定律,分析比较了两种集成系统中在设计工况下的热力学性能,并与生物质-空气气化冷热电联供系统的性能进行了比较;选取夏季和冬季的两个典型日的逐时冷热电负荷进行了变负荷性能分析,揭示了不同负荷条件下系统的热力性能变化。最后,基于(火用)经济性理论,结合品位的概念,修正建立了生物质-水蒸气气化冷热电联供系统的产品分摊模型,探究了在设计工况下系统各个部件的(火用)经济性,得到了冬夏两种工况下电、冷冻水(供热水)和生活热水的单位(火用)成本,通过变参数敏感性分析,揭示了生物质的单价、系统初投资、利率和运行时间等关键因素对联供系统产品单位(火用)成本的影响。
[Abstract]:Current energy shortage, environmental pollution and other problems are very serious, the proportion of renewable energy use is increasing. As a kind of renewable energy, biomass energy has become an important strategic choice in many countries because of its rich resources and low pollution. Based on the method of biomass steam gasification, this paper presents a reasonable method of utilizing biomass energy by integrating it with the combined cooling and heat supply system. Firstly, this paper presents two integrated systems for biomass gasification, which provide the heat needed by biomass gasification by burning biomass gas and using electric heating, respectively. The integrated system uses the heat pipe gas-liquid heat exchanger to recover the waste heat from biomass gas to produce the steam needed for gasification reaction, and the cascade utilization of energy is realized without the help of other steam generating devices. The thermodynamic mathematical models of two subsystems of biomass steam gasification and combined cooling and heat supply are established and verified. Secondly, three different operating conditions of biomass steam gasification cold, thermal and electric system are given: summer condition, winter condition and transitional season condition. Based on the first and second laws of thermodynamics, the thermodynamic performance of the two integrated systems under the design conditions is analyzed and compared, taking the cold thermoelectric load of a hotel in Beijing as an example. The performance of the system is compared with that of biomass air gasification combined cooling and heat supply system, and the variable load performance is analyzed on two typical days in summer and winter. The variation of thermodynamic performance of the system under different load conditions is revealed. Finally, based on the exergy economy theory and the concept of grade, the product allocation model of biomass steam gasification combined cooling and heat supply system is established, and the exergy economy of each part of the system under the design condition is explored. The unit exergy cost of electricity, refrigerated water (hot water supply) and domestic hot water under winter and summer conditions were obtained. The unit price of biomass and the initial investment of the system were revealed by the sensitivity analysis of variable parameters. The effect of key factors such as interest rate and operating time on unit exergy cost of co-supply system.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU83;TM61

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