延迟焦化混合喷雾冷焦新工艺数值研究

通过建立包含多孔介质模型、“等效流体”模型、二维轴对称焦炭塔流固耦合模型，对延迟焦化大吹气阶段新老工艺冷焦过程进行了数值模拟。计算得出了传统纯蒸汽冷焦工艺条件下焦炭塔温度分布并进行现场数据验证，预测了水汽喷雾冷焦新工艺下焦炭塔瞬态温度分布，分析了液态水含量对冷焦效果的影响及其规律，对新工艺的经济性进行了定量评价。结果表明：水汽喷雾冷焦新工艺下喷雾流量一定时，焦层冷焦效果随水汽喷雾的液态水含量的提高先显著改善后趋于稳定再受到抑制，当液态水质量分数为0.8时，冷焦效果达到最优；在压力为0.3 MPa条件下水汽喷雾为7.5 t/h时，液态水质量分数分别为0.4, 0.5, 0.6, 0.7, 0.8, 0.9时，相对传统蒸汽冷焦工艺，节约蒸汽量分别为36%，53%，64%，71%，79%，84%，年增经济效益76.14万元。结论对延迟焦化水带汽新工艺参数的调试与优化具有一定指导意义。

NUMERICAL SIMULATION OF NEW HYBRID ATOMIZATION PROCESS FOR COKE COOLING IN DELAYED COKER

A axisymmetric fluid solid coupled model of coke tower containing the equations of momentum and mass transfer of porous media, as well as the equivalent fluid model is developed in this paper, which is used to simulate both the traditional and a new cooling method by mixing spray with vapor in big flow unit of delayed coking. In the paper, the calculated transient temperature field of coke drum with shell model applied in pure vapor has been validated by the measured data. Meanwhile, it predicts transient temperature field of coke drum in new way of cooling, illustrates the impacts of the mass fraction of liquid water on the effects of coke drum cooling, and quantitative evaluated the vapor saving and economic cost of new process. The research results indicates that the cooling effect is first quickly improved then slow down and final restrained with the increase of content of liquid water, the optimum fraction is 0.8 to realize the best cooling effect. The article give the vapor saving percentage and annual saving cost at the liquid water fraction from 0.4 to 0.9in the condition that the pressure is 0.3MPa and the mass flow is 7.5t/h. The conclusions will be helpful for optimizing process parameters in delayed coking.