油页岩气体热载体干馏炉炉内流动特性

On Flow Characteristics of Oil Shale Gas Thermal Carrier Dry Distillation Furnace

对一台1 t/d油页岩气体热载体干馏炉炉内流场特性进行了数值模拟。基于计算流体力学的理论方法,采用以Ergun方程基础上建立的多孔介质模型、湍流模型进行研究。将模拟结果与前人研究成果进行对比分析,结果表明,采用添加阻力源项的多孔介质模型、RNG k-ε湍流模型等封闭模型能够较好的模拟炉内流场分布特性,并在原有结构基础上进行优化,增设同轴及偏心轴撞击流布气方式。在本文提出的布气方式下,无论采用同轴亦或是偏心轴布置,均能形成良好的速度场及压力场,提高干馏段气体混合程度,拓宽布气范围,增加气体与固体颗粒之间的接触面积和时间,强化换热进而确保干馏效果。模拟结果可为开发大容量气体热载体干馏炉及优化设计提供理论依据。

The way of gas distribution when the gas heat carrier is sent to the dry distillation furnace has a great influence on the oil shale dry distillation.The existing air distribution method has the following problems:the air distribution method is simple,the gas distribution range is narrow,due to which the gas heat carrier is unevenly distributed in the furnace,and the oil shale is heated for only a short time without being completely retorted when passing through the high temperature dry distillation section,causing waste of resources.To solve the problem,the flow field in a 1 t/d oil shale gas heat carrier dry distillation furnace was simulated numerically in computational fluid dynamics(CFD)theory in the porous medium model and turbulence model using the Ergun equation.Results show that the closed model could better simulate the flow field distribution characteristics in the furnace in the RNG k-εturbulence model and the porous medium model that added with the resistance source term.In addition,the flow field distribution was optimized based on the original structure by adding coaxial and eccentric shaft impact flow air distribution.In air distribution mode,a good velocity field and pressure field was formed by using either coaxial or eccentric axis arrangement,thus the gas mixing degree in the dry distillation section improved,the range of the gas distribution widened,the contact area and time between the gas solid particles increased,the heat exchange strengthened,and the dry distillation effect ensured.The simulation results may provide a theoretical basis for the development of large-capacity gas heat carrier dry distillation furnace and optimization design.