渣油加氢脱硫反应集总动力学模型的事前模拟

 通过渣油加氢脱硫(HDS)中试装置实测数据，对渣油HDS反应集总动力学进行事前模拟。根据渣油中硫化物加氢反应速率的快慢，将其分别划分为2~6个集总，建立了5种渣油HDS反应集总动力学模型。通过对该5种模型拟合误差的比较分析，得到三、四集总模型的拟合平均相对误差最小。然后分别针对三、四集总渣油HDS反应动力学模型，求取了其动力学参数，并采用实测数据对模型的稳定性和外推性进行了验证。结果表明，模型参数中，温度、空速和氢分压等因素对HDS反应的影响符合硫化物加氢反应规律，对三、四集总模型验证的平均相对误差分别为2.32%和1.98%，说明模型的拟合性和预测性良好。所建模型可为渣油HDS反应集总动力学的深入研究提供参考。     

催化重整集总反应动力学模拟

在Smith集总反应动力学模型基础上,建立催化重整轴向和径向反应器的数学模型,对工业装置进行模拟。并利用实际生产操作数据,对Smith模型动力学参数进行了优化。用优化后的模型对装置进行模拟计算,其结果与实际操作吻合较好。     

催化重整集总反应动力学模型研究

本文提出了一个包括16个集总组分的催化重整动力学模型,在氢气压力为(8～12)×10~5Pa、温度为460～500℃、氢油摩尔比为10的条件下测定了该模型的动力学参数.用最佳步长策略方法、Marquadt 方法及区域约束的参数估计方法估计出反应网络的动力学参数,计算出各个反应的活化能和频率因子.模型中各个组分的实验值与计算值的拟合很好,模型能较好地预测各组分的浓度分布.     

柴油加氢脱硫三集总动力学

采用固定床反应器，对加氢精制催化剂上的深度加氢脱硫(HDS)动力学进行研究，考察了反应温度、氢分压和空速对柴油脱硫效果的影响。根据柴油中各种硫化物的脱除行为，按被脱除的难易程度将柴油中的硫化物分为3类，构成三集总HDS模型，获得不同温度下的表观活化能(E)、指前因子(A)和对氢分压的分级数值。假定3类硫化物的活化能不变，将其指前因子与柴油的密度和馏程相关联，建立3个指前因子与中平均沸点的关系曲线，结合按温度切割的柴油窄馏分个数，建立三集总一级反应动力学模型，对方程进行了相关系数(R2)和残差检验。结果表明，所得动力学模型与实验数据吻合良好，在实际应用中可为开发新型超深度HDS催化剂及工艺提供理论指导。     

柴油深度加氢脱硫集总-反应机理动力学

将硫化物按照脱硫难易程度分为二集总,再根据二集总硫化物的反应路径建立了加氢脱硫集总-反应机理动力学模型,以镇海混合油为原料,利用中试装置的实验数据,拟合出该模型的各项参数,并验证了模型的精密性。结果表明:该模型形式简单,可以描述柴油硫化物脱硫的反应规律;利用其计算出的含硫量和实验值具有较高的吻合度,15组对比数据残差平方和为0.780。     

重油加氢裂化四集总反应动力学模型的研究

以800 kt/a重油加氢裂化装置为背景,根据加氢裂化反应机理,建立了四集总模型作为加氢裂化反应动力学模型。采用高斯-牛顿法对模型的参数进行了估计和四阶龙格-库塔法计算有初始值的常微分方程,并用现场实测数据进行了验证。结果表明:模型的计算值与实测值平均相对误差小于5%,因此该集总模型具有较高的模拟精度。     

FCC汽油S Zorb反应吸附脱硫过程中不饱和烃加氢反应的研究

S Zorb工艺可以将FCC汽油的硫质量分数降至小于10μg/g,但在脱硫过程中,由于反应体系中引入了H2,在吸附剂表面既发生了硫化物的脱硫反应,也不可避免地存在导致汽油辛烷值损失的不饱和烃的加氢反应。对比分析了中国石化上海高桥分公司S Zorb原料汽油和产品汽油的组成,从热力学和动力学角度分析了这些加氢反应对体系组分变化的影响,计算了标准压力下不同温度下的反应平衡常数K和Gibbs反应自由能ΔrGm,并采用四阶龙格-库塔法计算了每个反应的反应速率常数,这些数据可以为S Zorb装置工艺参数的进一步优化提供参考。     

基于多孔介质加氢裂化反应器多相流数值模拟

采用欧拉多相流模型,通过建立多孔介质能量守恒模型、热量传递模型和质量传递模型,对加氢裂化反应器内的多相流动、传热和传质进行了数值模拟计算,得到了反应器内多孔介质床层的速度场、温度场、浓度场和压力分布。结果表明,多相流模型的选取、传热传质模型的建立、油品物性的计算和边界条件的设置能够较准确地描述三相流动状态及其分布状态。反应器入口处的流动状况将直接向内部传递,壁面流随流动而发展,其宏观描述为：在出口床层处径向体积分率曲线出现拐点,进而使流体在催化剂床层径向和轴向分布不均匀,气化率得到提升。为了获得反应介质与催化剂充分混合的流体分布状态,有效利用催化剂,反应器入口处的流动状态必须得到优化。     

计算流体力学方法模拟规整填料塔内流体流动行为的研究进展

对采用计算流体力学(CFD)方法模拟规整填料塔内流体流动行为的研究进展进行了综述,分别介绍了单相流模型和两相流模型。单相流模型可预测气相或液相在规整填料塔内轴向、径向的扩散行为及气相的压头损失等;两相流模型主要研究规整填料塔内气液相流动行为,利用该模型可计算液体在规整填料表面的流动过程及气液相间的传质行为,其模拟结果比单相流模拟更接近实际。随流体力学学科和计算机技术及现代测量技术的进一步发展,将会促进CFD技术在化工过程中的应用。     

超重机内多孔板填料上气液流场的计算流体动力学模拟

采用Fluent软件对填料内径65 mm、外径250 mm的超重机内多孔板填料上的气液流场进行模拟研究。模拟结果表明,填料上的液体速度场分布不均匀;填料转速对液体的切向速度场有影响,液体入口速度对径向速度场有影响;填料上的气体静压力场分布很有规律;填料转速对气体干床压降的影响很小,气体流量对干床压降的影响较为明显;当填料转速为0¹ 000 r/min、液体入口速度为0.31 000 r/min、液体入口速度为0.3⁴.0 m/s时,液滴在填料上的运动轨迹呈螺旋线型,停留时间为0.104.0 m/s时,液滴在填料上的运动轨迹呈螺旋线型,停留时间为0.10⁰.94 s,运动路程为0.130.94 s,运动路程为0.13⁰.45 m;当气体流量为22.80.45 m;当气体流量为22.8¹32.3 m3/h、填料转速为0132.3 m3/h、填料转速为0¹ 000 r/min时,干床压降为71 000 r/min时,干床压降为7¹ 844 Pa。     

基于计算流体力学热流固耦合仿真的换热器折流板结构优化

采用多物理场耦合方法,建立了管壳式换热器的计算流体力学(CFD)热流固耦合仿真分析模型,对20种不同折流板结构参数的管壳式换热器进行了流动与传热的数值模拟。CFD仿真计算结果显示,换热器的折流板间距和折流板缺口高度对流动和传热的影响相互关联,不能进行单目标优化设计。以JF因子作为换热器综合性能的评价准则,对管壳式换热器的折流板间距和折流板缺口高度进行了结构优化设计,提出在换热器内径(d)200 mm、换热管长1 140 mm、并流条件下,该换热器的最佳折流板间距为80 mm(折流板数目为10),最佳折流板缺口高度为0.3d(即60 mm)。     

基于计算流体力学数值模拟的板式热交换器传热与流动分析

以新型鼓泡板式热交换器作为研究对象,通过计算流体力学软件,对鼓泡板冷、热两侧通道进行了数值模拟。板内流体流动研究表明,相同流速下,冷侧通道流体湍流强度高于热侧,压力损失也高于热侧;热侧通道由于扭曲泡相互接触造成阻挡作用,相较于冷侧通道,传热效果较差。将数值分析结果与试验值进行了对比,验证了数值分析结果的准确性,该数值分析结果对改善板式热交换器传热效率有一定指导意义。     

Reaction Processing of Fraction of Yanhua FCC Gasoline

By using fraction of Yanhua FCC gasoline as a feedstock, the effects of reaction temperature, weight hour space velocity, feedstock performance on yields of liquefied petroleum gas production, and aromatics and propylene are researched in a confined fluidized bed reactor. Aromatization index (AI) and competent parameter (CP) are first proposed to study the mechanistic pathways of aromatization reaction of fraction of Yanhua FCC gasoline. The experimental result shows AI values of FCC gasoline decrease with the increase of the reaction temperature under the same catalyst; CP values and the aromatization reaction function for the same catalyst increase with the increase of the reaction temperature. The isomerization reaction for fraction of Yanhua FCC gasoline has more advantage than that of the aromatization reaction.     

催化柴油管式液相加氢CFD模拟

The computational fluid dynamics(CFD) code, FLUENT, was used to simulate the liquid-phase FCC diesel hydrotreating tubular reactor with a ceramic membrane tube dispenser. The chemical reaction and reaction heat were added to the model by user-defined function(UDF), showing the distribution of temperature and content of sulfides, nitrides, bicyclic aromatics and monocyclic aromatics in different parts of the reaction bed. When the pressure was 6.5 MPa, the amount of mixing hydrogen was 0.84%(m), the space velocity was 2 h-1 and the inlet temperature was 633 K, the temperature reached a maximum at a height of 0.15 m, and the range of radial temperature reached its maximum(2.5 K) at a height of 0.15 m. It indicated that the proper ratio of height to diameter of catalyst bed in the tubular reactor was 5-6. The increase of inlet temperature, the mixing hydrogen and the decrease of space velocity led to the decrease in the content of bicyclic aromatics, sulfides and nitrides, and the increase in monocyclic aromatics content, while the high temperature increased. The results were in good agreement with experimental data, indicating to the high accuracy of the model.     

Study on Disproportionation Reaction of FCC Gasoline on Acid Catalyst

Based on the experimental data relating to the reaction of FCC gasoline on acid catalyst the analysis of product distribution, and composition of gasoline and diesel fractions have been analyzed. The occurrence of disproportionation reaction of FCC gasoline on acid catalyst and the network of disproportionation reaction have been identified. Study has also shown that different reaction temperatures can result in different pathways of disproportionation reactions on acid catalyst.     

Computational Fluid Dynamics Study for Flow of Natural Gas through High-pressure Supersonic Nozzles: Part 1. Real Gas Effects and Shockwave

Abstract

The computational fluid dynamics technique was used to study the behavior of high-pressure natural gas in supersonic nozzles. Although many applications of gas flow produce insignificant errors when the gas is assumed ideal, our results indicate significant variation of gas properties. This article illustrates natural gas behavior when it is considered to be real and how erroneous the properties may become when the gas is assumed to be ideal. The article also presents the influences of properties related to the flow of natural gas through supersonic nozzles. Using a quite accurate equation of state model, real gas effects are studied and compared with the perfect gas case. The results show a significant variation in gas properties estimation. Location of shockwave is also analyzed. The comparison of results for two gases (methane and nitrogen) indicated that shockwave position can significantly change when the gas is considered as real rather than perfect.     

Effects of Reaction Condition on the Secondary Aromatization Reaction of Lanlian FCC Gasoline Products

By using Lanlian catalytic gasoline aromatization production as a feedstock, the effects of reaction conditions on the aromatization product yield, conversion, motor octane number (MON), research octane number (RON), and solvent product compound were researched in a confined fluidized bed reactor. The experimental results show that the changeable trend of secondary aromatization yield of Lanlian FCC gasoline are the same with FCC gasolines under the operation condition. Although the aromatics contents of FCC gasoline after the secondary aromatization are about 5%, MON value of production decreases and RON value of production remain no change and coke yield contents are very high. These show that the qualities of secondary aromatization of FCC gasoline are very poor.