Design Of 100kW Micro Combustor And Study On Combustion Characteristics Of Variable Fuel

Since the 21 st century,the fuel cell field and its technology have developed rapidly.Among all kinds of fuel cells,the solid oxide fuel cell(SOFC)has more outstanding fuel applicability and can be used as a small independent mobile power supply.In the SOFC system with natural gas as the main fuel,the fuel cell will exhaust high temperature and low oxygen air and Anode Off Gas(AOG).In this paper,a high temperature and low oxygen burner is designed to provide heat source for the start-up and stability,improve the efficiency and fuel utilization of the whole SOFC system,and prevent environmental pollution.The main contents are as follows:(1)The overall layou of the burner,the parameters of air and fuel,the overall size of the combustion chamber and the size of the hydrocyclone at the head are designed and calculated.The design concept mainly comes from some key structures of a micro gas turbine combustor developed independently the combustion chamber of the micro gas turbine,and the main flame organization mode combining the strong swirl combustion and the adjacent angle pilot combustion is taken as the design idea.In addition,the starter of the burner is selected for the design condition,and the design parameters are based on the outlet parameters and design performance indexes of the fuel cell system.(2)The plane diagram and three-dimensional model of the burner are established.The structure of the burner is optimized by numerical simulation.By increasing the diameter of the front end of the variable cross-section position of the combustion chamber,the angle return area and the head pressure loss are reduced.By adjusting the blade angle of the primary axial hydrocyclone and the eccentricity of the flow passage of the secondary radial hydrocyclone,the return area and the flame organization mode in the combustion chamber are changed,so as to balance the flow rate and pressure loss of burner,ignition and stable combustion effect,combustion temperature and temperature uniformity,pollutant emission and other performance.It is found that when the blade angle increases to 60°,the return flow increases significantly;when the eccentricity increases to 28 mm or more,it is more favorable to form the flame organization mode of adjacent angle ignition.(3)The combustion conditions of the burner under different working conditions and using different Wobbe number fuels are studied.It is found that the combustor can achieve stable combustion in four working conditions,but the position of the main combustion area is not the same.The combustion of working conditions 1,3and 4 mainly occurs at the outlet of the flow passage of the hydrocyclone,and the adjacent angle is formed between each flow passage for ignition.The combustion position of working condition 2 is located at the axis of the flame tube downstream of the hydrocyclone.And it is found that the combustor can operate stably under four kinds of Wobbe number fuels of 5.37,7.69,10.46 and 13.89.However,a lower Wobbe number will result in a higher CO emission of the burner,and a higher Wobbe number will worsen the heating condition of the wall surface of the combustor.