基于CFX的多腔回转炉中催化剂颗粒加热的数值模拟

Numerical Simulation on Heating of Catalyst Particles in a Multi-chamber Rotary Kiln Based on CFX

采用计算流体动力学软件CFX研究多腔回转炉中催化剂颗粒的加热过程,预测物料在高温段的驻留时间,计算炉内物料、空气和炉壳的轴向温度分布及炉内热量分配.结果表明,将空气进口速度增大至2.5倍,驻留时间缩短至0.978倍,多腔回转炉消耗的电能增大至1.918倍,电能消耗主要由炉外壁向外散热转变为空气升温吸热;将物料进口速度增大至5倍,驻留时间缩短至0.193倍,多腔回转炉消耗的电能增大至2.047倍,电能消耗主要由炉外壁向外界散热转变为物料升温吸热;将多腔回转炉的热传导系数增大至4倍,驻留时间延长至1.007倍,多腔回转炉消耗的电能增大至1.147倍,电能消耗主要是炉壳外壁向外界散热.降低空气进口速度、适当减小催化剂进口速度和提高炉壳热传导系数对多腔回转炉的设计至关重要.模拟的炉壳温度与测量数据在规律和数值上都符合较好.

Based on the CFD software CFX, heating process of catalyst particles in a multi-chamber rotary kiln was analyzed, the residence time of catalyst particles in high temperature regions predicted, and the axial temperature distributions of catalyst particles, air and kiln were simulated. Thermal energy distributions inside the kiln were also simulated. The result comparison of multi-operating conditions reveals that as the air inlet velocity is increased to twice, the residence time shorten to 0.978 time and electrical energy increased to 1.918 times. Most of the power consumption is first attributed to the heat loss by outer wall of the kiln, and then the air temperature is raised. When the catalyst inlet velocity is raised to 5 times, its residence time decreased to 0.193 times, and electrical energy consumption increased to 2.047 times. Most of the power is first consumed by the outer wall, and the catalyst temperature raised. As the thermal conductivity coefficient of kiln is boosted to 4 times, the residence time lasts up to 1.007 times, and electrical energy consumption rises to 1.147 times. Most of the electrical power is lost through the outer wall. Low air inlet velocity, relatively low catalyst inlet velocity and relatively high kiln thermal conductivity are significant for design of such rotary kiln with good performance. The simulated temperatures are consistent with experimental data, validating the feasibility and correctness of simulation.