EPR1750MW核电机组热经济性分析模型建立及应用

发布时间：2018-03-10 21:27

本文选题：核电机组　切入点：热力系统　出处：《华北电力大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着经济的发展,我国能源消费量还会不断增长,同时环境污染的加重,再次引发全社会对以煤炭为主导的能源结构的反思。核电的安全发展已成为不可阻挡的趋势。在这样的情况下,提高核电机组的热经济性、降低发电成本,确保机组的安全运行具有重要意义。本文通过对比核电机组热力系统与常规火电机组热力系统的差异,结合压水堆核电机组二回路热力系统的特点,以国内EPR1750MW核电机组为例,建立便于使用矩阵分析法的核电机组热力系统热经济性分析的通用数学模型。在此基础上建立多元扰动下的热力系统能效分析模型,并对模型的映射规则、结构特点及使用规则加以说明。最后,通过计算得出了多元参数扰动对机组能效影响的强度系数。本文的主要研究内容以及所得结论如下:(1)分析压水堆EPR1750MW核电机组热力系统的特点,建立核电机组热力系统热经济性分析的统一物理模型。通过对比常规热平衡法计算各级抽汽系数,进一步证明了该模型的准确性。在统一物理模型的基础上,将原系统的循环吸热量方程、汽轮机内功方程和热力系统汽水分布方程分解为各级控制体的方程,并转化为矩阵方程,从而得出该机组的热力系统热经济性分析数学模型。并对机组能效矩阵方程进行微分等数学处理,进而得出影响机组能效的各个参数,使机组节能降耗有的放矢。(2)进行多元参数扰动对核电机组热经济性的分析。多元参数扰动包括广域性参数和局域性参数。其中,广域性参数主要包括主蒸汽压力、主蒸汽温度、再热蒸汽温度。局域性参数主要包含加热器侧的参数和辅助汽水的参数。计算出多元参数扰动对机组能效的影响,进而求出各扰动对能效的相对强度系数,即表示参数扰动每变化1%时,对机组能效变化量(/t tdηη)的影响程度。计算分析得:1)对于广域性参数扰动,在额定工况下,主蒸汽气压相对敏感度为0.028561,主蒸汽温度相对敏感度为0.10288,再热蒸汽温度的相对敏感度为0.064933。同时,低负荷时要尤为注意主蒸汽压力和再热气温的变化,在高负荷时需注意主蒸汽温度的变化。在一定范围内,当主蒸汽压力、主蒸汽温度、再热蒸汽温度增大时,会提高机组能效。2)对于局域性参数扰动,当加热器压损和上端差增大时,会降低机组的能效。同时1、3、4号加热器的抽汽压损相对敏感度较大,所以需要特别注意1、3、4号加热器的抽汽压损的变化。1、4号加热器上段差的相对敏感度较大,故而需要特别注意1、4号加热器的上段差变化。因此在机组维护和检修期间要着重注意1、3、4号加热器的变化,以有效提高机组的运行效率。3)广域性参数扰动相对敏感度比局域性扰动敏感度大100~1000倍,因此,在机组检修运行时,要优先控制工质温度,减少因工质温度扰动对机组能效产生的不利影响。(3)对EPR1750MW核电机组进行多元参数扰动下的能效分析研究,证明了分析模型的可用性,指出了影响机组能效的关键因素,为机组运行监督、提高机组热经济性提供了理论支持。
[Abstract]:With the development of economy, China's energy consumption will continue to grow at the same time, the aggravation of environmental pollution, once again lead the whole society to take coal as the dominant energy structure of reflection. The safety of nuclear power development has become an irresistible trend. In this case, improve the thermal economy of the nuclear power group, reduce power the cost is of great importance to the safe operation of the unit. The differences in thermodynamic system compared with conventional nuclear power generating units in thermal power plants, combined with the characteristics of the two loop thermodynamic system of PWR units, with domestic EPR1750MW nuclear power plant as an example, a general mathematical model for the analysis of nuclear power plant thermal system using matrix analysis of the energy efficiency analysis model was established. The thermodynamic system under multivariate disturbances on the basis of the model, and the mapping rules, structure and rules of use with examples. Finally, the strength coefficient of influence on unit efficiency of multiple parameter perturbation is calculated. The main research contents of this paper and the conclusion are as follows: (1) analysis of the characteristics of the thermodynamic system of PWR nuclear power plant EPR1750MW unit, the establishment of a unified physical model of nuclear power unit thermal economy. By conventional heat balance method all levels of the steam extraction coefficient, further proved the accuracy of the model. Based on the unified physical model, the original system of the cycle heat absorption equation of steam turbine, the steam water distribution and strength equation of thermodynamic system equation into the body at all levels of the control equation, and transformed into matrix equation, thus obtains the thermal economy of the unit analysis the mathematical model of energy efficiency. And the matrix equation processing differential mathematics, and then draw the influence of various parameters of unit efficiency, make targeted energy saving unit . (2) multiple parameter analysis of the nuclear power plant thermal economic disturbance. The multiple parameter perturbation parameters include wide area and local area parameters. The parameters include the main steam pressure, main steam temperature, reheat steam temperature. The parameters of the local parameters mainly include the parameters and the auxiliary steam water heater side. Calculate the impact on unit efficiency of multi parameter perturbation, and then calculated the relative intensity of disturbance coefficient on energy efficiency, said parameter disturbance changes every 1%, the unit efficiency variation (/t TD ETA ETA) influence. Calculation and analysis: 1) for a wide area of parameter perturbation, in rated condition. The main steam pressure relative sensitivity is 0.028561, the main steam temperature relative sensitivity is 0.10288, the relative sensitivity of reheat steam temperature for 0.064933. low load at the same time, great care should be taken to change the main steam pressure and reheat temperature in high. Pay attention to the change of the load of main steam temperature in a certain range, when the main steam pressure, main steam temperature, reheat steam temperature increases, will increase the energy efficiency of.2) for local parameter perturbation, when the heater and the upper pressure loss difference increases, will reduce the energy efficiency. At the same time pumping pressure loss 1,3,4 the heater is relatively more sensitive, so we need to pay special attention to the 1,3,4 heater extraction steam pressure loss changes.1,4, the relative sensitivity of upper heater difference is large, so we need to pay special attention to the upper 1,4 heater difference. So during the maintenance and repair units to focus on the change of 1,3,4 heater, to.3 running efficiency improve the unit's) wide parameter perturbation relative sensitivity than local disturbance sensitivity 100~1000 times, therefore, the unit maintenance operation, should give priority to control the temperature of working fluid, less for refrigerant temperature The degree of disturbance influence on unit efficiency. (3) analysis of multiple parameters under the disturbance of energy efficiency of EPR1750MW nuclear power plant, proved the availability analysis model, points out the key factors affecting the energy efficiency of the unit, the unit operation and supervision, provide theoretical support to improve the thermal efficiency of the unit.

【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】：TM623.3

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