GE LM2500+SAC型燃气轮机压气机积垢判据的确定

Indicators for determining compressor fouling of GE LM2500+SAC gas turbines

及时发现燃气轮机压气机叶片积垢故障并进行水洗作业,能够降低机组的运行维护成本,有助于避免其他气路故障的发生。以2台天然气长输管道LM2500+SAC型燃气轮机为例,建立了基于气路热力参数的燃气轮机压气机性能计算模型,分析压气机水洗作业前后压气机等熵效率、进气质量流量、耗功等的变化,结果表明:水洗作业后2台压气机等熵效率分别提升0.9%、1.5%,但每运行2 000 h将会带来约1%的压气机等熵效率衰减,在叶片表面积垢达到一定程度后效率衰减趋于稳定;压气机积垢每造成1%的等熵效率衰减,将造成约2%的折合质量流量衰减;水洗对降低机组功耗有明显的效果,但环境温度升高也会导致压气机耗功增加,因此耗功并不适合作为压气机积垢的判据,可采用同压比下等熵效率衰减、同转速下压气机质量流量衰减作为判断压气机是否积垢的依据。

Timely detection of compressor fouling of gas turbines and removal of such fault through washing can effectively reduce operation and maintenance costs and also eliminate possibilities of other faults in gas lines. With two LM2500＋SAC gas turbines for long-distance gas pipelines as examples, a calculation model for compressor performances of gas turbines based on thermal parameters of gas lines was established to analyze changes in isentropic efficiency, mass flow rate of in- coming gases and energy consumptions before and after washing of such compressors. Research results show that, after washing operations, isentropic efficiencies of two compressors enhance by 0.9% and 1.5%, respectively. However, the isentropic efficiencies decline by approximately 1% for every 2 000 h in operation and tend to be stable when the fouling on the blade surface reaches certain extent. Whenever the isentropic efficiencies decline by 1%, equivalent mass flow rate decreases by approximately 2%. Washing operations may effectively reduce energy consumption, but increases in environmental temperatures may lead to increases in energy consumption. Consequently, energy consumption may not be taken as an indicator for determining compressor fouling. Instead, reductions in isentropic efficiencies under identical compression ratios and reductions in mass flow rate of the compressor under identical rotation speed are recommended as such indicators. （8 Figures, 1 Table, 12 References）