基于迭代的注汽锅炉烟气再循环热力参数计算及对燃烧的影响

Iteration Calculation of FGR Thermodynamic Parameters in Steam Injection Boiler and Effect on Combustion

为准确研究烟气再循环技术对燃气注汽锅炉相关燃烧特征参数的影响,依据实际燃烧过程中采用烟气再循环,烟气中含有额外氧的情况,对燃烧过程所需的氧化剂和产生的烟气含量进行了迭代计算,并以此结果为基础,开展锅炉热力计算,分析了烟气再循环率对燃烧效率、排烟温度、燃料消耗量、理论燃烧温度的影响。结果表明:与未采用迭代计算相比,迭代计算后的结果更加精确;迭代计算后,随着烟气再循环率升高,迭代计算与未迭代计算间的误差也逐渐升高;当烟气再循环率升高至20%时,迭代计算的燃烧耗氧量和产生烟气量与未迭代相比,分别降低了4.29%和3.86%;随着烟气再循环率升高,排烟温度逐渐升高,但锅炉效率也略有提高,进而使锅炉燃料量降低,同时降低炉膛内的燃烧温度。

In order to research the effect of flue gas recirculation (FGR) technology on combustion characteristic parameters in gas-fired steam-injection boilers more accurately, the volume of required oxidizer and produced gas were calculated with iterative methods in consideration of the extra oxygen existing in combustion by flues gas recirculation and based on it to analyze the effect of flues gas recirculation rate on combustion efficiency, exhaust gas temperature, fuel consumption and theoretical combustion temperature. The results proved that iteration calculation was more accurate compared with non-iteration calculation;the deviation between iteration calculation and noniteration calculation raised with the increasing of the flue gas recirculation rate;when the flue gas recirculation ratio reached 20%, the required oxidizer and produced gas calculated with iteration dropped 4.29% and 3.86% respectively compared with non-iteration calculation;and, with the increase of flue gas recirculation rate, the exhaust gas temperature increased gradually, thus the boiler efficiency increased slightly, the fuel consumption of the boiler reduced correspondingly, and the theoretical combustion temperature in the furnace reduced.