660MW超临界机组能效分析模型的建立与应用

发布时间：2018-05-25 05:07

  本文选题：超临界机组 + 热力系统　； 参考：《华北电力大学》2017年硕士论文

【摘要】：能源是我国经济发展的重要支柱和动力,随着全球资源的日渐枯竭以及环境问题的日趋严重,如何实现节能减排是当今社会实现可持续发展所面临的主要问题。在我国的能源发电结构中,火力发电仍然占据着主要地位,而超临界机组因其节能高效的特点,已逐渐成为我国火力发电机组中的主力机组。因此对超临界机组进行能效分析具有重要的现实意义。火电机组在实际运行中,热力系统参数不可能一直维持不变。当热力系统参数发生变化时,不可避免的会对机组的热经济性产生影响。为了研究超临界机组热力系统扰动对机组能效的影响情况,针对超临界机组热力系统结构特点,对其进行建模分析及热经济性计算。主要研究内容和成果如下:(1)根据能量守恒方程和质量守恒方程,改进了热力系统热经济性分析统一模型和多元扰动下热力系统能效分析模型,将直接进出汽轮机侧的辅助汽水对机组能效的影响加入模型中,使模型更加完善。(2)以矩阵的微积分运算法则为基础,推导了多元扰动下的热力系统能效分析模型的积分模型,并根据不同类型扰动对机组热力系统热力参数的影响特点,建立了适用于局域性扰动和广域性扰动的能效分析模型。以某660MW超临界机组为例验证了模型的正确性,比较了积分模型和原模型在一定扰动范围内的准确性。(3)计算了算例机组的广域性扰动敏感度系数。通过计算可知:在100%THA负荷下,主汽压扰动绝对敏感度系数为0.00158/MPa,主汽温扰动绝对敏感度系数为0.000162/℃,再热汽温扰动绝对敏感度系数为0.000121/℃。且随着机组负荷的降低,主汽压扰动和再热器温扰动对机组能效的影响程度逐渐增大,主汽温扰动对机组能效的影响程度逐渐减小。(4)计算了算例机组的局域性扰动敏感度系数。计算结果表明:随着机组负荷的降低,辅助汽水流量扰动对机组能效的影响程度逐渐增大,而且辅助汽水回收利用跨越能级越大其对机组能效的影响程度越大;各级加热器抽汽压损扰动对机组能效的影响程度逐渐减小;上端差扰动对机组能效的影响程度基本不变。此外,1号加热器和6号加热器的上端差扰动和抽汽压损扰动的敏感度系数要明显高于其他加热器,在机组运行中应重点监测1号加热器和6号加热器的运行状态。(5)计算了算例机组广域性多元组合扰动对机组能效的影响,并与原模型和常规热平衡法比较。计算结果表明;在计算广域性多元组合扰动时,积分模型与常规热平衡法之间的相对误差不超过3.5%,且准确性在整体上要略高于原模型。(6)分析比较了不同类型扰动的相对敏感度系数。结果表明:广域性扰动对机组能效的影响要远远大于局域性扰动,而工质温度对机组能效的影响要大于工质压力对机组能效的影响;主蒸汽压力扰动相对敏感度系数基本不随负荷变化而变化。
[Abstract]:Energy is an important pillar and motive force of China's economic development. With the depletion of global resources and the increasingly serious environmental problems, how to achieve energy saving and emission reduction is the main problem that the society faces to achieve sustainable development. The thermal power generation still occupies the main position in the energy generation structure of our country, and the supercritical unit has become the main unit in our country because of its energy saving and high efficiency. Therefore, the energy efficiency analysis of supercritical units has important practical significance. In the actual operation of thermal power units, the thermodynamic system parameters can not always remain unchanged. When the thermodynamic system parameters change, the thermal economy of the unit will inevitably be affected. In order to study the influence of thermal system disturbance of supercritical unit on unit energy efficiency, the thermal system of supercritical unit was modeled and analyzed and its thermal economy was calculated according to the structural characteristics of thermal system of supercritical unit. The main research contents and results are as follows: (1) according to the energy conservation equation and mass conservation equation, the unified thermal economic analysis model of thermal system and the energy efficiency analysis model of thermal system under multivariate perturbation are improved. The influence of auxiliary steam water directly in and out of steam turbine side on unit energy efficiency is added to the model to make the model more perfect. Based on the matrix calculus algorithm, the integral model of energy efficiency analysis model of thermal system under multivariate disturbance is derived. According to the influence of different types of disturbances on the thermodynamic parameters of unit thermal system, an energy efficiency analysis model suitable for local disturbance and wide area disturbance is established. The correctness of the model is verified by taking a 660MW supercritical unit as an example. The accuracy of the integral model and the original model in a certain disturbance range is compared. The calculation results show that under 100%THA load, the absolute sensitivity coefficient of the main steam pressure disturbance is 0.00158% MPA, the absolute sensitivity coefficient of the main steam temperature disturbance is 0.000162 / 鈩，

本文编号：1932198