Investigating the Effect of Fuel Rate Variation in an Industrial Thermal Cracking Furnace With Alternative Arrangement of Wall Burners Using Computational Fluid Dynamics Simulation

摘要

A new arrangement of side-wall burners of an industrial furnace was studied by three-dimensional computational fluid dynamics (CFD) simulation. This simulation was conducted on ten calculation domain. Finite rate/eddy dissipation model was used as a combustion model. Discrete ordinate model (DOM) was considered as radiation model. Furthermore, weighted sum of gray gas model (WSGGM) was used to calculate radiative gas properties. Tube skin temperature and heat flux profiles were obtained by solving mass, momentum, and energy equations. Moreover, fuel rate variation was considered as an effective parameter. A base flow rate of fuel (<(m) over dot> = 0: 0695 kg/s) was assigned and different ratios (0.25 <(m) over dot>, 0.5 <(m) over dot>, 2 <(m) over dot>, and 4 <(m) over dot>) were assigned to investigate the heat distribution over the furnace. Resulted temperature and heat profiles were obtained in nonuniform mode using the proposed wall burner arrangement. According to the results, despite increased heat transfer coefficient of about 34% for <(m) over dot>-4 <(m) over dot>, temperature profile for this rate is too high and is harmful for tube metallurgy. Also, the proper range for fuel rate variation was determined as 0.5-2 <(m) over dot>. In this range, heat transfer coefficient and Nusselt number for <(m) over dot>-2 <(m) over dot> were increased by 21% and for <(m) over dot>-0.25 <(m) over dot> were decreased by about 28%.