燃气-蒸汽联合循环动力装置热力学分析

Thermodynamic Analysis of Gas-Steam Combined Cycle Powerplant

为了研究燃气蒸汽联合循环系统的节能潜力,用分析的方法对该系统进行了热力学分析。通过对一种常见的燃气蒸汽联合循环系统的模拟计算,给出了各部位损失的大小及分布,对其能量利用情况进行了评价,并找出了薄弱环节,提出了节能措施。结果表明,燃气蒸汽联合循环系统利用了燃气侧高温吸热和蒸汽侧低温放热的特点,使得其效率高达51.12%,比常规的纯蒸汽动力循环的效率(最高约40%)高得多;燃料化学能转化为热能及传热引起的损失所占比例最大,为31.67%。所以,改善燃烧和传热过程的不可逆性,是提高联合循环效率的重要途径;发展联合循环发电技术,研制和开发新型发电机是高效节能,有利于可持续发展的根本所在。研究结果为系统的总体优化设计提供了理论依据。

In order to study the energy-saving potential that can be recovered, the thermodynamic analysis of a gas-steam combined cycle system is done using exergy analytic methods. The exergy loss of each part, the energy utilization, and its weakness and the energy-saving method are presented here after the simulated computation. The result of study shows that the exergy efficiency of the combined cycle can reach 51.12% because of utilizing the high-temperature endotherm of gas side and the low temperature exotherm of steam side. It is much higher than that of simple steam cycle(of which is not more than 40%). The most exergy loss is aroused by the transform from fuel chemical energy to heat energy as well as the heat transfer process, the ratio is 31.67%. Therefore, it is very important to improve the irreversibility of burning and heat transfer process. On the other hand, to progress combined cycle generation technology and develop new generators are the foundation of saving energy.