燃料热值对不同燃烧方式下燃气轮机燃烧特性的影响

Effect of Fuel Calorific Value on Combustion Characteristics of Gas Turbine in Different Combustion Modes

针对燃气轮机运行过程中出现的燃烧不稳定和污染物排放高的问题,开展了燃料热值对不同燃烧方式下燃气轮机燃烧特性(燃烧稳定性和污染物排放影响规律)影响的研究。以某重型燃气轮机分管燃烧室为研究对象,在扩散燃烧和预混燃烧方式下,保持燃料流量、空气流量及大气温度等参数不变,仅改变燃料热值,采用数值仿真方法对燃烧室设计监测点处压力、燃烧室出口温度及污染物排放等数据进行分析。研究表明:在扩散燃烧方式下,热值较低时,燃烧室高频压力脉动较大,热值增加,燃烧室低频压力脉动先减小后增加;在预混燃烧方式下,热值增加,燃烧室高频压力脉动减小;在两种燃烧方式下,热值增加,燃烧室出口NO_(x)排放均增加,而热值变化对燃烧室出口CO的排放影响较小。

Aiming at the problems of combustion instability and high emissions during gas turbine operation, the effects of fuel calorific value on gas turbine combustion characteristics which included the influence rule of combustion stability and pollutant emission in different combustion modes were studied. Taking a heavy-duty gas turbine can-type combustion chamber as the research object, the parameters such as fuel flow, air flow, atmospheric temperature were kept constant in the diffusion and premixed combustion modes, only the fuel calorific value was changed.And the numerical simulation method was adopted to study and analyze the data of the design monitoring point pressure and outlet temperature of combustion chamber and the pollutant emission. The research results show that the high-frequency pressure pulsation of the combustion chamber is larger when the calorific value is lower, and the fuel calorific value is increased, the low-frequency pressure pulsation of the combustion chamber is decreased initially, followed by an increasement in the diffusion combustion mode. In the premixed combustion mode, when the fuel calorific value is increased, the high-frequency pressure pulsation of the combustion chamber is decreased. In two combustion modes, when the fuel calorific value is increased, the NO_(x) emission is increased at the outlet of combustion chamber, while the change of fuel calorific value has little effect on the CO emission of the combustion chamber outlet.