Research On Enhanced Heat Transfer Characteristics In Ethylene Cracking Furnace Tube

Ethylene cracking furnace is a big energy consumer in the petrochemical industry.Whether the comprehensive thermal efficiency of the cracking furnace can be effectively improved has a great impact on the production cost of ethylene.This article aims to optimize the furnace tube structure of the cracking furnace,strengthen the heat transfer performance of the furnace tube,and reduce the coking in the tube is an important way to increase the olefin yield and reduce the production cost.This paper proposes a new type of open spiral tube,which is used in ethylene cracking furnace to enhance heat transfer and improve overall performance.This article first uses numerical simulation to analyze in detail the flow characteristics and heat transfer performance of the fluid in the smooth tube,ordinary spiral tube and open spiral tube.The results show that ordinary spiral tube and open spiral tube can effectively improve the internal strengthening.Heat transfer,and compared with ordinary spiral tube,the drag coefficient of open spiral tube is reduced by33% to 43%.The PEC value of the open spiral tube is between 1.0 and1.35,which has excellent comprehensive heat transfer performance.Secondly,this paper studies the influence of the opening angle α,the opening depth S,the radial width W and the twist ratio Y of the open spiral fin tube on the flow and heat transfer characteristics,and analyzes the differences through the comprehensive heat transfer performance coefficient PEC as a measurement index.In addition to the comprehensive performance of the open spiral tube under the structure,this paper also applies the vortex identification method based on the Q criterion to analyze the turbulence of the fluid in the tube and the field synergy theory to judge the heat transfer performance of the tube,and to strengthen the transfer The thermal mechanism was analyzed.After completing the analysis of the influence of various structural parameters on the open spiral tube,this paper also uses orthogonal experiment design and genetic algorithm to optimize the four key parameters of the open spiral tube,and obtains the angle between the openings α = At 15°,when the radial width is 0.25 R,the opening depth is 0.1R,and the twist ratio is3,the comprehensive heat transfer performance of the open spiral fin tube is the best,which is verified by the fimicon function in MATLAB software.Finally,the optimal structure of the open spiral sheet tube was applied to the ethylene cracking furnace,and the reliability of the simulation was verified by comparison with industrial data.Subsequently,the fluid in the U-shaped tube equipped with the open spiral fins was subjected to a coupled simulation of flow heat transfer and cracking reaction,and the final simulation data was analyzed and processed.It can be found that the open spiral fin tube can effectively improve the thermal efficiency of the cracking furnace and the yield of key products.Has a good comprehensive performance.