供热系统动态特性的模拟研究及在电力调峰中的应用

发布时间：2019-02-14 17:37

【摘要】：热电联产作为一种高效利用能源的生产方式,已经得到国内的外广泛认可和大力发展。但目前,供热机组大多采用“以热定电”的方式运行,随着电力峰谷差逐年增长,热电厂调峰能力不足的问题日益显著,如何解除机组热电负荷的耦合关系,使热电机组在保证供热质量的同时,为电网提供更多的调峰容量,成为亟待解决的问题。从质量及能守恒出发,假设管网已经处于水力平衡状态,建立了供热系统中主要设备的能量流动模型,并根据实际系统运行特点对模型进行适当简化,着重考虑了影响系统热动态特性方面的参数。以数学模型为基础,建立了完整的一、二次网供热系统仿真模型,以间接连接供热系统为研究对象,对系统的输送延迟和蓄热特性进行了仿真分析,并利用该特性,结合热电负荷变化特点,提出了可以使热电机组参与电力调峰的系统运行调节方式,以及有效提高供热机组电力调峰能力的方法。对所建立的一次管网进行了动态仿真,通过改变热源供热量,定量分析了一次管网的输送延迟及蓄热特性。分析结果发现,热水在管道中的流动是导致输送延迟的主要原因；在热源供热量发生变化时,管壁温度与热水温度相比变化较慢,此时管壁可以作为蓄热体发生蓄热或放热,减缓水温及输送热量的变化,从而影响用户最终所得的热负荷。对用户室内热环境进行了动态仿真,分析了建筑围护结构和内蓄热体与室内空气的换热过程,研究发现,两者都可以减缓室外温度变化以及供热负荷变化等因素对室内温度的影响。以一、二次供热系统的动态特性分析为依据,在供热系统质调节方法的基础上,提出了可以使热电机组参与电力调峰的两种系统运行调节方案,该方案采用分时段改变供热量的调节方法,根据不同时段负荷特点和供热机组热、电负荷耦合关系,确定不同时段的供热量。仿真模型模拟运行结果表明,两种方案均可以有效提高供热机组调峰能力,且对热用户室温影响较小,在分时电价制度下,调峰运行方式还可以提高热电厂的发电收益,验证了两种方案的有效性和经济性。
[Abstract]:As an efficient energy production mode, cogeneration has been widely recognized and developed in China. But at present, most heat supply units are operated by "heat fixed power" mode. With the increase of power peak and valley difference year by year, the problem of insufficient peak-shaving capacity of thermal power plant is becoming more and more obvious. It is an urgent problem to ensure the heating quality and provide more peak-shaving capacity for the power grid. Starting from the conservation of mass and energy, the energy flow model of the main equipment in the heating system is established, and the model is appropriately simplified according to the operating characteristics of the actual system, assuming that the pipe network is already in the state of hydraulic balance. The parameters affecting the thermal dynamic characteristics of the system are emphatically considered. Based on the mathematical model, a complete simulation model of primary and secondary network heating system is established. The transmission delay and heat storage characteristics of the system are simulated and analyzed. Based on the characteristics of thermoelectric load variation, this paper puts forward the system operation regulation mode which can make thermoelectric units participate in power peak shaving, and the method to effectively improve the power peak shaving ability of heat supply units. The dynamic simulation of the primary pipe network is carried out. By changing the heat supply from the heat source, the transportation delay and heat storage characteristics of the primary pipe network are quantitatively analyzed. The results show that the flow of hot water in the pipeline is the main reason for the delay of transportation. When the heat supply of the heat source changes, the tube wall temperature changes more slowly than the hot water temperature. In this case, the tube wall can be used as a regenerator to store or release heat, slow down the change of water temperature and heat transfer, and thus affect the final heat load of the user. The dynamic simulation of the indoor thermal environment of the user is carried out, and the heat transfer process of the building enclosure structure and the inner heat storage body and indoor air is analyzed, and the results show that, Both of them can slow down the influence of outdoor temperature change and heating load change on indoor temperature. Based on the analysis of the dynamic characteristics of the primary and secondary heating systems, and on the basis of the quality regulation methods of the heating systems, two kinds of system operation and regulation schemes which can enable the thermal power units to participate in the power peak shaving are put forward. According to the load characteristics of different time periods and the coupling relationship between heat and electricity load of heating units, the heat supply in different periods is determined. The simulation results show that both schemes can effectively improve the peak-shaving capacity of heating units, and have little effect on the room temperature of heat users. Under the time-sharing price system, the peak-shaving operation mode can also increase the power generation income of the thermal power plant. The effectiveness and economy of the two schemes are verified.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU995;TM73

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