压气机抽气储能改进燃气轮机能源系统灵活性分析

Analysis on Improving Flexibility of a Gas Turbine-Based Energy System With Compressor Bypass Air Extraction for Energy Storage

需求侧负荷波动致燃气轮机能源系统难以全工况高效、灵活匹配外界负荷,基于此提出在单轴燃气轮机组的压气机出口抽气,构成空气储/释能的燃气轮机能源系统。采用燃气轮机变工况典型性能解析分析法,研究压气机抽气对燃气轮机主要部件及机组运行性能的影响,并提出可行的机组负荷控制策略。以系统满足一种简单延时阶跃函数分布的逐时电负荷为例,研究峰谷比、负荷频率等特征参数对系统设计参数及供电效率的影响。分析表明,压气机抽气使其流量增大,压比显著下降;技术上燃气透平能等排气温度工作于文中所设的最大抽气系数为0.3的范围内;燃气轮机效率-负荷特性劣于基准系统,但提高了供热品位,增强其灵活性。当峰荷为4600kW、峰谷比为3、谷荷频率为0.375时,燃气轮机设计功率为4048kW,系统增效达2.02个百分点。为了提高大峰谷比情景下的系统效率及灵活性,可以考虑引入太阳能光热储能,提高空气透平的进气参数。

The variation in the demand-side loads generally brings about a difficulty in the load matching of gas turbine energy systems with high efficiency and great flexibility in the overall load range. Thus, a new concept of compressed air energy storage/release system was introduced into single-shaft gas turbines, where compressor exhaust air was extracted for energy storage. With the analytical solutions for gas turbine part-load performances, the influence of compressor bypass air extraction on the operation performances of gas turbine and its main components was analyzed; and also, a feasible direction was discussed for the renovation in the load control strategy of the gas turbines. Taking a daily demand-side power distribution with delay-step fimction as a case study, the influences of the peak-valley ratio and load frequency on system capacities and power efficiency were studied. The analysis indicates that, compressor bypass air extraction results in an increment in air mass flow rate, anda considerable reduction in compression ratio. The turbine can technically operate under constant exhaust temperature within the range of air extraction rate 0.3. The gas turbine part-load performance is inferior to the reference one, whereas has advantages in higher exhaust temperature and greater flexibility. At peak-valley of 3 and valley load frequency of 0.375, gas turbine capacity can be designed as 4048 kW to meet the peak power load of 4600kW; the power efficiency increment reaches 2.02 per cent. It is proposed that solar-energy storage be further introduced for increasing the inlet temperature of air turbine, in aim to enhance the system efficiency and flexibility.