氢-氧联合循环效率的主要影响因素分析

Main Affecting Factors of Hydrogen and Oxygen Hybrid Cycle Efficiency

在分析基本联合循环的基础上,提出了氢-氧联合循环系统,分析了影响氢-氧联合循环效率的主要因素.结果表明:随着最高温度和最高压力的提高,循环的热效率也不断提高,在温度为1700℃、压力为30 MPa时,效率可达到62%;中压燃气透平的膨胀比以及膨胀比的分配都存在1个最佳值,在温度为1 500℃、压力为30 MPa时,中压燃气透平最佳膨胀比为8.0左右,效率可达到60.5%,此时最佳膨胀比分配值为1.43;最佳膨胀比的分配在亚临界区域随着总膨胀比的升高而降低,在超临界区域随着总膨胀比的提高先降低后升高,在总膨胀比为30左右的时候出现拐点;通过对回热和再热系统参数的优化,氢-氧联合循环可以达到更高的热效率.

The hydrogen and oxygen hybrid cycles were put forward based on analyzing the basic combined cycle. The main factors which affect the efficiency of hydrogen and oxygen hybrid cycle were also analyzed. Results show that the heat efficiency of the cycle gets increased with the increasing of the maximum temperature and pressure of the cycle. The efficiency reaches 62% when the temperature is at 1 700℃ and the pressure is at 30MPa. There is one optimum value for both the expansion ratio of the middle pressure gas turbine and expansion ratio distribution in the system. When the temperature is 1 500℃ and the maximum pressure is at 30MPa, the optimal expansion ratio of the middle pressure gas turbine is approximately 8.0, then the efficiency can achieve 60.5%, at the same time the optimal expansion ratio distribution is at the point of 1.43. The optimal expansion ratio distribution decreases with the total expansion ratio of the gas turbine increasing in the sub-critical area, while it decreases at first and increases latterly in the super- critical domain. There occurs a transition point when total expansion ratio reaches approximately 30. The hydrogen and oxygen hybrid cycle system can obtain a higher efficiency by optimizing the parameters of the recuperation and reheat systems.