Abstract:

Geometrical model development and gridding compartmentalization of twin fireboxes cracking furnace were performed with software Gambit. The radiation and convection cells of cracking furnace were simulated with standard k-ε turbulence model，finite-rate/eddy-dissipation combustion model and P1 radiation model of the computational fluid dynamics software Fluent. Stimulation results showed that the flue gas temperature in the cracking cell is higher than that in the decoking cell；in the central surface of tubes，the pressure of the cracking cell is a little higher but the line speed is much greater than those in the decoking cell；the distribution of tube metal temperature in the cracking cell is different from that in the decoking cell. Although the flue gas average temperature of the coil outlet in the cracking cell is higher than that in the decoking cell，the flue gas of higher temperature does not flow into the decoking cell，and the flue gas temperature field of the convection cell become gradually uniform with the increase of the height. The results showed that the cracking and decoking switch operation in twin fireboxes cracking furnace is feasible，and the framework and operation can be further optimized.

摘要：

用Gambit软件对双辐射段裂解炉进行几何建模和网格划分，选择计算流体力学软件Fluent的标准k-ε湍流模型、有限速率/涡耗散燃烧模型和P1辐射模型，对裂解炉辐射段和对流段进行数值模拟计算。模拟计算结果表明，裂解辐射段的烟气温度高于烧焦辐射段；在炉管中心面处，裂解辐射段的压力略高于烧焦辐射段，烟气流动的线速度明显大于烧焦辐射段；两个辐射段的炉管管壁温度分布不一致。尽管裂解辐射段的横跨段出口面烟气平均温度高于烧焦辐射段，但高温烟气没有流入烧焦辐射段且流向对流段的烟气温度场随着对流段高度上升逐渐均匀，该计算结果说明了双辐射段裂解炉的裂解/烧焦切换操作是可行的，并可进一步优化双辐射段裂解炉的结构和操作。