催化裂化装置中旋风分离器设计及结构优选研究

发布时间：2018-03-20 07:20

本文选题：旋风分离器　切入点：正交法　出处：《东北石油大学》2016年硕士论文　论文类型：学位论文

【摘要】：旋风分离器是炼油厂催化裂化反应再生系统中重要装置,实际生产中旋风分离器的分离效率普遍较低,催化裂化过程中需要大量的催化剂,旋风分离器收集大颗粒催化剂,比较容易,而细小的催化剂则大量跑损,浪费资源的同时,也污染环境。本文利用计算流体动力学软件,以某石化总厂催化裂化装置中旋风分离器为基础模型,围绕旋风分离器的两个主要性能指标:分离效率和压降,对旋风分离器内气固两相流的运动进行了研究,并对基础模型进行结构及参数优选。合理的湍流模型能够准确的预报旋风分离器内的气相流场,本文利用多种湍流模型对旋风分离器进行模拟,将模拟结果与前人LAD测试结果进行对比分析,最终确定RSM湍流模型为旋风分离器气相模拟所采用的模型。由于旋风分离器内固相颗粒的浓度较低,所以固相采取随机轨道模型(DPM)进行模拟分析。在确定湍流模型后,对旋风分离器初始模型进行模拟分析,分析从旋风分离器初始模型的速度场、颗粒运动轨迹、颗粒分级效率、旋风分离器总效率及压力降等参数入手。对这些参数进行分析后得知,初始模型的分离特性较差,对大颗粒的分离能力较好,对细小颗粒的分离能力需要提高。为了保证计算的准确性,本文确定了模型收敛的判断依据,即同时满足残差曲线收敛、压力系数曲线趋于平稳、总体质量流率达到平衡这三点才能确定模型计算已经收敛。在对基础模型分析的基础上,针对分离效率低的情况,对旋风分离器的入口形式、主直径、排气口直径、排尘口直径、圆柱段长度、入口倾斜角度、排气口伸入长度、锥体角度、防返混锥顶角角度进行优选,由于分析的因素比较多,利用两次正交试验,在确保结果科学真实的基础上,减少计算量。通过两个正交试验的优选,得出优选结构。为了符合实际应用,在优选结构的基础上,加装灰斗,并对防返混锥的位置进行了优选。通过对比分析优选前后的模型,结果表明优选后的模型具有较好的分离性能,且压力降低于初始模型,选取合适的操作参数,最终达到降阻增效的目的。
[Abstract]:The cyclone separator is an important unit in the catalytic cracking reaction regeneration system of the refinery. The separation efficiency of the cyclone separator is generally low in actual production. A large number of catalysts are needed in the process of catalytic cracking, and the cyclone separator collects large particle catalysts. It is easy to use, while the small catalyst loses a lot of resources and pollutes the environment at the same time. In this paper, the cyclone separator in the FCC unit of a petrochemical plant is used as the basic model by using the computational fluid dynamics software. The movement of gas-solid two-phase flow in cyclone separator is studied around two main performance indexes: separation efficiency and pressure drop. The reasonable turbulence model can accurately predict the gas phase flow field in the cyclone separator. In this paper, a variety of turbulence models are used to simulate the cyclone separator. By comparing the simulation results with the previous LAD test results, it is determined that the RSM turbulence model is the model used in the gas phase simulation of the cyclone separator, because the concentration of solid particles in the cyclone separator is relatively low. After determining the turbulence model, the initial model of cyclone separator is simulated and analyzed, and the velocity field, particle trajectory, particle classification efficiency of the initial model of cyclone separator are analyzed. Based on the analysis of the total efficiency and pressure drop of the cyclone separator, it is found that the separation characteristics of the initial model are poor and the separation ability of the large particles is better. The separation ability of fine particles should be improved. In order to ensure the accuracy of calculation, this paper determines the judging basis of model convergence, that is, the convergence of residual curve is satisfied, and the pressure coefficient curve tends to be stable. On the basis of the analysis of the basic model, aiming at the low separation efficiency, the inlet form, the main diameter and the outlet diameter of the cyclone separator are studied. The diameter of dust outlet, the length of cylinder section, the angle of inlet inclination, the length of exhaust outlet, the angle of cone and the angle of anti-mixing cone are selected. Because there are many factors in the analysis, two orthogonal tests are used. On the basis of ensuring the scientific truth of the results, the calculation amount is reduced. Through the optimum selection of two orthogonal experiments, the optimal selection structure is obtained. In order to meet the practical application, the ash hopper is added on the basis of the optimized selection structure. By comparing and analyzing the model before and after the optimization, the results show that the model has better separation performance, and the pressure is lower than the initial model, and the appropriate operating parameters are selected. Finally, the purpose of reducing resistance and increasing efficiency is achieved.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TE967

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