基于ASME及GB能量平衡法下锅炉热效率不确定度评定及敏感性分析

Uncertainty Calculation and Sensitivity Analysis in Steam Generator Thermal Efficiency Test based on ASME and GB Energy Balance Method

研究了ASME PTC4-2013标准和GB10184-2015的热效率计算方法以及不确定度计算理论,分别建立锅炉热效率及不确定度计算的理论模型,并以某350 MW机组超临界煤粉锅炉的热效率试验为例,对热效率结果进行了不确定度评定,研究各因素测量不确定度对锅炉热效率测试不确定度的贡献。结果表明:采用ASME试验标准,锅炉热效率测量试验质量高于GB标准;ASME标准下排烟温度测量不确定度分量、飞灰可燃物不确定度分量所占锅炉热效率合成不确定度权重值大于GB标准;ASME标准下空预器出口氧量测量不确定度分量所占锅炉热效率合成不确定度权重值小于GB标准;无论是ASME标准还是GB标准,排烟温度测量不确定度分量、空预器出口氧量测量不确定度分量均远大于其他测量参数不确定度分量;为了降低锅炉热效率不确定度,提高测试质量的途径应在试验设计与实施阶段优化对重要因素测量仪器的精度选择及测点布置。

This article studied the method of thermal efficiency calculation and calculation of uncertainty theory of ASME PTC4-2013 and GB 10184-2015,and presented the theory model of the steam generator efficiency calculation and calculation of uncertainty,respectively.With one 350 MW supercritical pulverized coal boiler thermal efficiency test as an example,the uncertainty of the result of the thermal efficiency was evaluated and the contribution of various factors to the measurement uncertainty on the boiler thermal efficiency test quality was studied.The results showed that test quality of boiler thermal efficiency of ASME standard is higher than GB standard.The uncertainty component occupied by gas temperature and fly ash in the boiler thermal efficiency synthesis uncertainty under ASME standard is greater than that with GB.The uncertainty component occupied by measurement of oxygen of APH outlet is less than GB standard.The uncertainty component occupied by gas temperature and APH outlet oxygen are much higher than the uncertainty component that other measurement parameters have.In order to reduce the uncertainty of boiler thermal efficiency,the way to improve test quality is to optimize the precision selection of measuring instrument and measurement point layout with important factors in the stage of test design and implementation.