| Environmental problems and the structure of coal as the main energy resource have determined the importance of clean combustion technology in China. IGCC is a very promising technology in the current technology of clean combustion. As an important part of the whole system, the development and research of gas turbine technology is very important. High NOx emissions is a problem when syngas is burned in traditional gas turbine because of the low heat value and high heat balance temperature, meanwhile, it is necessary to prevent the phenomenon of tempering In practical engineering as H2 is very easy to burn. Therefore, it is necessary to reform the traditional gas turbine.In this paper, we used the self-designed 25 nozzle micro-mixing burner to explore the combustion characteristics of syngas. The 25 unit nozzle is arranged on the surface of the combustion chamber of the burner bottom, with 5 rows of 5 square distribution. Each unit nozzle is composed of a vertical fuel nozzle and surrounding eight air nozzle with with a certain angle, in which way it compose an independent swirl combustion unit. The independent combustion unit disperse the flame surface, reducing the local heat load and combustion temperature, which is beneficial to reduce the NOx emission and protect the spray nozzle. At the same time, the burner can be put into a different number of nozzles for work:9 nozzles,13 nozzles and 25 nozzles, fuel nozzle diameter can also choose 2.3mm,2.0mm and 2.8mm. The burner is designed to adjust the distance between the nozzles and the relative distance between the fuel nozzle and the air nozzle, so as to realize the diffusion and premixed combustion.In order to deeply understand the performance of the burner, we carried out some hot state experiments. Experimental results show that the micro-mixing burner can effectively organize the combustion under different experimental conditions. The flame is cone and the root of the flame is fine, the flame gradually spread and blend that the flame gradually widened, forming the main combustion zone because of the fuel itself gradually spread and the interaction of fluid between unit nozzle. In addition, it is not difficult to find that the method of micro-mixing can effectively reduce the pollutant emissions that the NOx and CO emissions are low. The experimental measurement and numerical simulation results show that the velocity distribution law of the helium gas with equal momentum is most close to that of hydrogen gas. The independent jet flow from combustion chamber’s nozzle exit gradually expanded in the whole process that flow to the downstream movement. The whole flow field can be divided into 3 regions: the main jet combustion zone, low-speed recirculation zone between the adjacent nozzles and large recirculation zone between the unit nozzles and combustion chamber wall. The presence of these recirculation zones in the combustion chamber can accelerate the uniform mixing of fuel and air, which is helpful for combustion At the same time, the velocity of the flow from the nozzle within a very small distance firstly drop and then rise, after that it rapidly fall and gradually stabilized. The central section’s velocity distribution of the combustion chamber can be well corresponding to the structure of the burner. There are 5 velocity peaks and the velocity of the middle nozzles is slightly higher while it’s lower near the wall of the burner. In addition, we calculate the single nozzle and the central section’s pulse velocity distribution of the micro-mixing burner. The pulse velocity is small, which shows that the design performance of the burner is great. |
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