Study On The Heat Transfer Process Of Natural Gas Non-catalytic Partial Oxidation Burner Rim

In the process of non-catalytic partial oxidation of natural gas,the burner is one of the key components,and its life is one of the important factors that affect the production efficiency and economic benefits.In this paper,the heat transfer process of burner rim in the process of the natural gas non-catalytic partial oxidation is studied through experiments and numerical simulation,which provide a theoretical basis for the design and application of high-load natural gas burners.The experiments show that the increase in the airflow velocity in the open space reduces the heat transfer of the flame radiation,so the heat transfer of the burner rim decreases.In the furnace,the increase in the airflow velocity increases the convective heat transfer,which the proportion of total heat transfer also gradually increased,so that the heat transfer of the burner rim gradually increased.Increasing O2/natural gas ratio increases the combustion temperature,but in the open space also increases the oxygen velocity,so that heat transfer of the burner rim tends to increase first and then decrease.Increasing O2/natural gas ratio in the furnace will make the heat transfer of the burner rim continue to increase,but the magnitude of the change will gradually decrease with the increase of the ratio of oxygen to natural gas.The addition of CO2 in oxygen will affect the reaction path and heat transfer process.This process transformed the system from a reaction dominated by CO2+H to a reaction dominated by CO2+H and meanwhile the content of polyatomic gas that hinders flame radiation is increased,so that the heat transfer of the burner rim will decrease abruptly as the CO2 content increases.The effect of preheating temperature and gas load has been studied by a non-catalytic partial oxidation simulation model.The results show that the increase in natural gas preheating temperature causes the combustion move upstream,raising the combustion temperature and increasing the heat transfer of the burner rim.In the process of reducing the load and maintaining the airflow speed in the burner channel by preheating the gas,when both gases are preheated,the recirculating speed is slightly reduced,and the temperature near the burner rim is slightly increased.The heat transfer of burner rim gradually increases,but its amplitude is within 10%.When only O2 is preheated,the recirculating speed decreases and the temperature near the burner rim is basically unchanged.At this time,the heat transfer of the burner rim gradually decreases,and its amplitude is also within 10%.The method of pre-heating natural gas and/or oxygen can better achieve the method of adjusting the high duty ratio of the natural gas reformer.The effects of burner structure towards the burner rim heat transfer,temperature and thermal stress were investigated.Studies have shown that the two-channel burner with CO2 added to the oxygen channel is compared to the three-channel burner with CO2 between oxygen and natural gas and the three-channel burner with CO2 outside oxygen and natural gas.In the two-channel burner CO2 can be well mixed with other gases,which makes the combustion area elongated and the temperature near the burner rim is lower.The better mixing of CO2 also reduces the radiation heat transfer to burner rim and to some extends has advantages in temperature and thermal stress.