基于EBSILON的燃气-蒸汽联合循环系统高冷负荷下供能特性分析

Energy supply characteristics of gas-steam combined cycle system at high cooling load based on EBSILON

为研究燃气-蒸汽联合循环在较高制冷负荷下的供能特性,以SGT-600小型燃气轮机组为顶循环与余热锅炉蒸汽轮机组为底循环的联合循环为研究对象,利用EBSILON软件分别建立了燃气轮机组、余热锅炉-蒸汽轮机组、双效溴化锂吸收式制冷机组及电制冷机组的耦合模型,比较分析了采用吸收式制冷与电制冷直供冷情况下,耦合系统在燃气轮机组变工况下的总发电效率、能源综合利用率及净电能节约率等供能特性。研究结果表明:燃气轮机组的发电效率随燃气轮机组的负荷率的降低而降低,在高冷负荷下,蒸汽轮机组发电效率与综合能源利用率却随燃气轮机组负荷率而逐渐增加;耦合系统的能源综合利用率随着吸收式冷负荷的增加而增加,在燃气轮机组一定的负荷率下,耦合系统的净电能节约率随着额定冷负荷的增加而提高,在吸收式冷负荷达到20 MW时,系统净电能节约率在燃气轮机组70%负荷率下最高能达到6.20%;但在较低的额定冷负荷条件下,采用吸收式制冷机组的效果反而不如直接利用电制冷机组进行直供冷。

To study the energy supply characteristics of gas-steam combined cycle at heavy refrigeration load, the combined cycle using SGT-600 gas turbine as the top cycle and heat recovery steam generator(HRSG) steam turbine as the bottom cycle is taken as the research object, the coupling models of gas turbine unit, HRSG-steam turbine system, double effect Li Br absorption chiller and electric chiller are established respectively by employing the EBSILON software. The energy supply characteristics of the coupling system under variable working conditions, such as total power generation efficiency, comprehensive energy utilization rate and net electric power saving rate, are compared under the condition of absorption refrigeration or electric refrigeration direct cooling. The results show that, the generation efficiency of the gas turbine decreases with the load rate of the gas turbine. At high cooling load, the generation efficiency and comprehensive energy utilization ratio of the steam turbine increase with the i load rate of the gas turbine. The comprehensive energy utilization ratio of the coupling system increases with the absorption cooling load. Under a certain load rate of the gas turbine, the comprehensive energy utilization ratio of the coupling system increases with the absorption cooling load. The net electric power saving rate increases with the rated cooling load. When the absorption cooling load reaches 20 MW, the maximum net electric power saving rate of the system can reach up to 6.20% at 70% load rate of the gas turbine unit. However, at lower rated cooling load, the effect of using absorption chiller is not as good as directly using electric chiller for direct cooling.