Structure Optimization And Numerical Simulation Of Natural Gas Burner

Industrial boilers play an important role in the national economy.Most of China’s boilers are mainly coal-fired,with low efficiency and heavy pollution.With the development of economy,the energy structure in China has changed from the original extensive development to the current pursuit of economic benefits.At the same time,the environmental problems brought by development have gradually emerged.Based on the dual problems of energy and environment,China has put forward new requirements on the energy structure and gradually increased the proportion of non-fossil energy.China is abundant in natural gas reserves.Meanwhile,China has basically built a pipeline network of domestic and imported gas sources.The natural gas supply can meet the growing demand.Natural gas is clean and efficient energy source and usher in a period of rapid development.Domestic industrial boilers gradually phase out small coal-fired boilers,and clean and the efficient gas-fired boilers become the focus of development.The researches on combustion technology of boilers in China mainly focuses on coal combustion,and there is few researches on gas combustion.The burners of domestic gas-fired boilers mainly rely on imports,so domestic enterprises should carry out the research on gas technology.At the request of an enterprise,three kinds of burners were designed according to the existing boiler structure.The influence of the swirling installation angle on the flow field in large space was studied by software simulation.It was found that the larger the swirling installation angle,the greater the swirling intensity by analyzing the combustion temperature,velocity,vector and burning rate under different swirling angle.The better the mixing effect of air and gas,the better the combustion effect that shorten the flame length.Compared to the large space,the combustion burner in the limited space makes a significant difference.Through simulating the combustion in a self-designed burner in a limited space,it was found that natural gas mixed with air get the better combustion efficiency and burning intense.Moreover,the pollutants information are increased in the combustion process.In order to reduce the pollutants,the airflow is finally carried out by segmental air supply,narrowing the high temperature area and decreasing the temperature in the furnace.In this paper,the numerical simulations were performed to study the effects ofdifferent proportions of primary air,internal secondary swirling wind and external secondary wind on combustion with segmented air supply.By analyzing the temperature distribution,velocity,vector,burning rate and pollutant concentration in the furnace during combustion,it is found that when primary air volume is 3%,the internal secondary swirling air volume is 40%,and the external secondary air volume is 57%,in the combustion furnace the temperature at the high temperature area is small,and the pollutant emission can basically meet the requirements of pollutant discharge rules in Jiangsu and Zhejiang Provinces.At this air supply ratio,the minimum combustion load is 0.6 and the maximum combustion load is 1.2.