基于无网格方法的四叶草型催化剂体相温度分布数值模拟

NUMERICAL SIMULATION OF TEMPERATURE DISTRIBUTION IN FOUR-LEAF SHAPE CATALYST BY MESHLESS METHOD

以四叶草型及圆柱型加氢裂化催化剂三维体相环境为计算实体,以模拟工业运行温度的函数作为边界条件,采用无网格数值方法求解傅里叶传热方程,并根据计算结果分析加氢裂化反应过程中工况条件及催化剂尺寸对于催化剂内部温度分布的影响。结果表明:在加氢裂化反应中,圆柱型及四叶草型催化剂颗粒内部的最高温度及平均温度均随反应放热量、空速、原料密度、催化剂半径及催化剂长度的增加而增大,其中反应放热量和催化剂半径对催化剂内部温度的影响更显著;即使在理想的宏观等温反应条件下,两种催化剂内部仍然是非等温区域;在工况条件及催化剂半径和长度均相同时,四叶草型催化剂内部的最高温度、平均温度均低于圆柱型催化剂,具有比圆柱型催化剂更均匀的温度分布。

Based on three-dimensional bulk of real four-leaf type hydrocracking catalyst, the meshfree calculation to solve the fourier partial differential equation for heat transmission was used to simulate the influence of external temperature fluctuation on the internal temperature distribution in the catalyst using industrial operating temperature and catalysts size as the boundary conditions. The analysis results show that the reactions in the catalyst do not occur under real isothermal surroundings. The maximum and average temperature increases in the cylindrical and four-leaf type catalyst as the increase of reaction heat release, space velocity, feed density, catalyst radius and length of the catalyst. Among them, the heat release and catalyst radius have much more influence. Even under ideal apparent isothermal reaction conditions, the non-isothermal area still exists in the two catalysts. When the operation conditions and catalyst size are the same, the four-leaf type catalyst has the highest internal temperature, while its average temperature and distribution are lower and better than cylindrical one.