基于机炉综合影响分析的机组最佳运行压力

Optimum Operating Pressure of Unit Based on Comprehensive Influence Analysis of Boiler and Steam Turbine

在机侧定滑压运行方式优化的前提下,从锅炉系统整体角度出发,采用单参数变化的原则建立理论计算模型,通过计算工质侧吸热量以及烟气侧的放热量来分析主汽压力变化对锅炉效率的影响。计算结果表明,提高锅炉的主汽压力可以降低锅炉的排烟温度,从而减少锅炉的排烟热损失;而且排烟温度的降低会减少锅炉灰渣物理热损失,但影响程度较小。另外,锅炉主汽压力的提高,使工质侧的汽化潜热减少,因此有利于提高炉膛内的温度水平,更有益于煤粉的燃烧,降低飞灰可燃物的含量,同样有利于提高锅炉的燃烧热效率。通过优化运行压力,可提高机炉整体的经济性。

Under the premise of optimizing the running mode of the steam turbine constant sliding pressure,from the perspective of the whole boiler system,the theoretical model to simulate detailed behavior of the boiler itself based on the principle of single parameter variation was established.The energy balance equations considering the heat absorption of working fluid and heat release of flue gas were satisfied to investigate the influence of pressure variation of main steam on boiler efficiency.The results show that increasing main steam pressure can lead to a reduction in the temperature of flue gas,and consequently,a decline in exhaust heat loss.The temperature decrease of flue gas will also result in a drop of heat loss due to extraction of boiler slag,however,the influence tends to be very limited.In addition,the latent heat reduces in accordance with the increase of main steam pressure,which further contributes to the rise of temperature in the furnace,the combustion of pulverized coal,the content of combustible materials in fly ash,and the improvement of combustion efficiency.By optimizing the operating pressure,the overall economy of the unit is improved.