烟气成分对锅炉效率计算精度的影响

Influence of Flue Gas Composition on Accuracy of Boiler Efficiency Calculation

分别采用迭代法和解析法,按照烟气焓温关系式是否考虑干烟气成分的差异,针对3种燃料定量分析了烟气成分对修正到完全没有漏风时的空气预热器出口烟气温度(TFgLvCr)和锅炉效率计算精度的影响。结果表明:烟气成分对TFgLvCr的计算精度有较明显的影响,在空气预热器的性能计算中不应被忽略;TFgLvCr的计算精度随着空气预热器进口干烟气氧气体积分数(фDpO2En)的提高而逐渐提高;在使用迭代法时,TFgLvCr的计算精度随着燃料收到基高位发热量(Qar,gross)的提高而提高;在使用解析法时,TFgLvCr的计算精度受Qar,gross影响不大;对TFgLvCr而言,解析法的计算精度高于迭代法;在某一个фDpO2En下,锅炉效率的计算精度最高,该点的位置取决于燃料和算法;在某一个Qar,gross下,锅炉效率的计算精度达到最高,该点的位置取决于фDpO2En和算法。

The effects of gas composition on computational precision of T FgLvCr and boiler efficiency were quantitatively analyzed with 3 kinds of fuel respectively using iterative and analytical method in the case with no air leakage and considering the variation of dry gas composition in the relations between tempeature and enthalpy of gas. Results show that the gas composition has considerable effect on the computational precision of T FgLvCr which should not be ignored in the performance calculation of air heater; the computational precision of TFgLvCr increases with the rise of ФDpO2En ; the computational precision of T FgLvCr increases with the rise of Qar.gross, using the iterative method, which is slightly affected by Qar.gross using the analytical method. For the TFgLvCr, the computational precision of analytical method is higher than the iterative method. For a certain ФDpOzEn, there exists a highest computational precision of boiler efficiency, corresponding to which the point depends on both the fuel category and the calculation algorithm, whereas for a certain Qar.gross ,there also exists a highest computational precision of boiler efficiency, corresponding to which the point depends on both the ＋ ФDpO2 En and the calculation algorithm.