05 反应器模型

史上最全的反应器结构及工作原理图解！这里给大家介绍一下常用的反应器设备，主要有以下类型：①管式反应器。

由长径比较大的空管或填充管构成，可用于实现气相反应和液相反应。

②釜式反应器。

由长径比较小的圆筒形容器构成，常装有机械搅拌或气流搅拌装置，可用于液相单相反应过程和液液相、气液相、气液固相等多相反应过程。

用于气液相反应过程的称为鼓泡搅拌釜（见鼓泡反应器）；用于气液固相反应过程的称为搅拌釜式浆态反应器。

③有固体颗粒床层的反应器。

气体或(和)液体通过固定的或运动的固体颗粒床层以实现多相反应过程，包括固定床反应器、流化床反应器、移动床反应器、涓流床反应器等。

④塔式反应器。

用于实现气液相或液液相反应过程的塔式设备，包括填充塔、板式塔、鼓泡塔等（见彩图）。

一、管式反应器一种呈管状、长径比很大的连续操作反应器。

这种反应器可以很长，如丙烯二聚的反应器管长以公里计。

反应器的结构可以是单管，也可以是多管并联；可以是空管，如管式裂解炉，也可以是在管内填充颗粒状催化剂的填充管，以进行多相催化反应，如列管式固定床反应器。

通常，反应物流处于湍流状态时，空管的长径比大于50；填充段长与粒径之比大于100(气体)或200（液体），物料的流动可近似地视为平推流。

分类：1、水平管式反应器由无缝钢管与U形管连接而成。

这种结构易于加工制造和检修。

高压反应管道的连接采用标准槽对焊钢法兰，可承受1600-10000kPa 压力。

如用透镜面钢法兰，承受压力可达10000-20000kPa。

2、立管式反应器立管式反应器被应用于液相氨化反应、液相加氢反应、液相氧化反应等工艺中。

3、盘管式反应器将管式反应器做成盘管的形式，设备紧凑，节省空间。

但检修和清刷管道比较困难。

4、U形管式反应器U形管式反应器的管内设有多孔挡板或搅拌装置，以强化传热与传质过程。

U形管的直径大，物料停留时间增长，可应用于反应速率较慢的反应。

5、多管并联管式反应器多管并联结构的管式反应器一般用于气固相反应，例如气相氯化氢和乙炔在多管并联装有固相催化剂的反应器中反应制氯乙烯，气相氮和氢混合物在多管并联装有固相铁催化剂的反应器中合成氨。

Reactor Modeling gObjective:Introduce the various classes of eacto ode s a a ab e. reactor models available. References:•Unit Operation Models Reference Manual,U it O ti M d l R f M lChapter 5, Reactors•Web site /Reactor OverviewReactorsBalance BasedRYi ld Equilibrium BasedRE ilKinetics BasedRYield RStoic REquilRGibbsRCSTRRPlugRBatchRStoic:Stoichiometric Reactor•Performs mass balance calculations based onyreaction stoichiometry and flashes the outlet stream•Used when reactions kinetics are unknown or unimportantMaterial(Any number)Heat (Optional)Heat (Optional)Water Decant (Optional)Material (One)Reactor Modeling with AspenRStoic:Specifications•Use Setup Reactions sheet to specify theyStoichiometry and molar extent or conversion for each reaction.•Use Setup Specifications sheet theto specify reactor outlet operating conditions.–Two of temperature, pressure, duty and vaporfraction–The phases to consider in flash calculations(p q)(Default: Vapor‐Liquid)Reactor Modeling with AspenSpecifications RStoic: (Continued)Reactor Modeling with AspenReactions•RStoic: Reaction stoichiometryÖReactants have ‐stoichiometric coefficients ÖProducts have + stoichiometric coefficients reactions•Multiple –Simultaneous reactions (or Independent Reactions)•Example:CH 2ClCH 2Cl →HCl + CHCl=CH 2CH 2ClCH 2Cl →C 2H 2+ 2HCl–Series reactions (or Chain Reactions) •Use products from previous reactions as reactants Reactor Modeling with Aspenp p •Example:C 3H 6+ C 6H 6→C 9H 12RStoic: (Continued)Reactions•Each reaction requires an extent or fraction conversion.•Reaction extent is:rate of moles generated for any componentthat component’s stoichiometric coefficient •Fraction conversionis:Fractional conversion of a key reactant componentReactor Modeling with AspenReactions RStoic: (Continued)Reactor Modeling with AspenSeries reactions (or Chain Reactions)Heats of ReactionRStoic:•In general no need to enter heats of reaction•Calculated from the inlet and outlet material stream enthalpiesh l iHeat of Reaction = Enthalpy Leaving blockHeat of Reaction=Enthalpy Leaving block–Enthalpy Entering block–Added or Cooling dutyAdded or Cooling dutyReactor Modeling with AspenHeats of Reaction RStoic: •Use the Setup Heats of Reaction sheet tocalculate or specifythe heats of reaction.p y For thiscalculation typeYou must specify RStoic reports Do not calculateheat of reactionNothing Nothing C l l t h t fR N R f H t f R ti Calculate heat of reactionRxn No., Reference Component Heats of Reaction Specify heat ofRxn No Reference Reactor heat duty Specify heat of reaction Rxn No., Reference Component, Heat of Reaction Reactor heat duty based on thespecified heats ofReactor Modeling with AspenreactionRStoic: (Continued)Heats of Reaction•Must provide specifications for ALL reactions •the same reaction number as given on Use Setup Reactions sheet.•The reference component must be a reactant Th f bfor that reaction•Heat of reaction are calculated:–Atthe specified reference conditions–Based on consumption of a unit mole of thereference reactant selected for each reaction.f l d f h iReactor Modeling with AspenHeats of ReactionRStoic:InputResultsReactor Modeling with AspenHeats of ReactionRStoic: (Continued)•If the specified heat of reaction differs fromp pthe heat of reaction that Aspen Plus computes from the heats of formation at reference conditions.conditions–RStoic adjusts the calculated reactor heat duty to the differencesreflect differences.–Outlet stream enthalpy will not be consistent withreactor duty except:d•Heat duty set to zero. Outlet temperature will includespecified heat of reactionifi d h f iReactor Modeling with AspenResultsRStoic:•Summary–Outlet temperature and pressure–Heat duty–Net heat dutyh d–Molar vapor fraction•Mass moleMass, and enthalpy balance•Phase equilibrium of the outlet stream•Reactions–The calculated/specified molar extent–The calculated/specified heats of reaction (Optional)Th S l i i f d i h f•The Selectivity of product component with reference to a reactant component. (Optional)Reactor Modeling with AspenResultsRStoic: (Continued)Reactor Modeling with AspenEquilibrium Based Reactors qObjective:Detailed introduction to the specification and results of REquil and RGibbs reactor models.bb d lEquilibrium Based Reactors •Equilibrium Reactors–REquil–RGibbsk i ki i i•Do not take reaction kinetics into accountp,p•Solve similar problems, but problem specifications are different•Individual reactions can be at a restrictedI di id l ti b t t i t d equilibrium using a temperature approach to equilibrium or molar extent of reaction.Equilibrium Reactor REquil: b d h l d h l b b l •Computes combined chemical and phase equilibrium by solving reaction equilibrium equations •Useful when there are many components, a few known reactions, and y p ,,when relatively few components take part in the reactions (Optional)Material(Any number)(Optional)Material (Vapor)Heat Heat Material (Liquid)Slide 19Reactor Modeling with AspenSpecificationsREquil:• on the REquil Input Specification sheet Specifiedthe Reactor Conditions:–Specify two of•Temperature•Pressure•Vapor FractionV F i•Duty–Valid phases•Vapor‐Liquid•Vapor‐Only•‐Liquid Only•Solid‐Only•NOT Vapor‐Liquid‐LiquidSpecifications REquil: (Continued)EquilibriumREquil:•Calculates equilibrium constants from Gibbs energyl l l b f bb•Can restrict equilibrium by specifying one of:–Molar extent of the reaction–A temperature approach to chemical equilibrium•Temperature approach is the number of degrees above the reactor temperature at which chemical equilibrium is determined.T Equil=T R+ ΔTReactionsREquil:•Use the REquil Reactions sheet to define the reaction stoichiometry.h l h d f h h•By default REquil assumes that reactions will reach equilibrium (p pp)(Temperature approach = 0o).Slide 23REquil:Results•Summary–Outlet temperature and pressure–Heat duty–Net heat duty y–Molar vapor fractionMass, mole and enthalpy•Mass balance •Equilibrium constants. Not reported for ti h t i t d l t t reactions where restricted molar extent specified.REquil: (Continued)ResultsKinetics Based Reactors Objective:Detailed introduction to the specification and results of RCSTR, RPlug and RBatch reactor models. l d h d lKinetics Reactors•Kinetic reactors–RCSTR–RPlug–RBatch•Used to study reactions in model detail •Require–Some geometric details of thereactor–Details of the reaction stoichiometry and kineticsReactor Modeling with Aspen PlusMarch 27, 2009Slide 27Kinetics Reactors: RCSTR •RCSTR performs a mass and energy balance around an idealcontinuous stirred tank reactor with known reaction kinetics –Perfect Mixing is assumed on both Macroscopic andP f t Mi i i d b th M i dMicroscopic levelsHeat (Optional)Material (Any Number)Heat (Optional)MaterialRCSTR: Specifications •Specified on the Setup Specification sheet the:f d h f h h–Reactor Conditions•andPressure either Duty or Temperature –Holdup specifications:•Valid Phases to consider in RCSTR calculations–Vapor Only (Default)–Liquid Only–Vapor‐LiquidV Li id–Vapor‐Liquid‐Liquid–‐WaterLiquid Free–Vapor‐Liquid‐Free Water•Volume or Residence Time for Reactor holdupRCSTR: Specifications (Continued)RCSTR: Phase Volume•Override this calculations by specifying:p y–The volume of a phase directly–The volume of a phase as a fraction of the total reactorvolume–Residence timeRCSTR: Phase Volume (Continued)•Use the Setup Specifications sheet to definep g g how the phase volume/residence time is going to be specified.RCSTR: Reactions•Can handle kinetic and equilibrium type reactions•Specify reactions using a Reaction Set ID on the Setup Reactions sheet.sheetRCSTR: UserRoutines •User kinetics through the Reaction Set IDp –Calculate the reaction rates for each componentRCSTR: Results•Summary–Outlet Temperature–Heat Duty–Net Heat Duty–Total Reactor Volume,–Volume of each of the phases present including salts–Condensed Phase Volume.Volume occupied by thecondensed phases (liquid and solid) present in the reactor –Total Reactor Residence Time–Residence time of vapor and condensed phasesRCSTR: Results •Material and energy balances around the blockKinetics Reactors RPlug: •Performs a mass and energy balance around an ideal plug flow reactor.A f t i i i th di l di ti •Assumes perfect mixing in the radial direction •Assumes no mixing occurs in the axial direction O i l l l b ifi d•Optional coolant stream can also be specified Material CoolantMaterial (Optional)Material Material Coolant(Optional)RPlug:Specifications•Use the Setup Configuration sheet to specify–Reactor tube length–Reactor tube diameter–Number of tubes (optional)–Valid Phases•One, two or three‐phases•Vapor‐Only is the default•Use the Setup Pressure sheet to specify the pressure drop across the reactor.•Additional input depends on the reactor type chosen.Specifications RPlug:RPlug:Reactor types•There are 7 reactor types available–Reactor with Specified temperature–Adiabatic reactor–Reactor with constant coolantR t ith t t l t–Reactor with co‐current coolant–Reactor with counter‐current coolant–Reactor with specified coolant temperature profile –Reactor with specified external heat flux profileRPlug:Adiabatic Reactor•No required specifications•Temperature is calculated at each axial position based on the enthalpy balance.th l b lReactionsRPlug:•Can handle kinetic reactions•Cannot handle equilibrium reactions•Specify reactions using a Reaction Set ID on the Setup Reactions sheetRPlug: RoutinesUser•User kinetics through the Reaction Set ID–Calculate the reaction rates for each component•Heat Transfer–Calculate the heat transfer rates per unit reactor wall area at any point along the reactori l h•Pressure dropl l h d f b h h d –Calculate the pressure drop for both the process andcoolant streams at any point along the reactor.ResultsRPlug:•SummaryS–Heat DutyMinimum Temperature–Reactor–Reactor Maximum Temperature–Residence Time (average for all phases presentin the process stream)gy•Material and energy balances around the block •Profiles results versus reactor length–Process stream conditions–Coolant stream conditions–Property set propertiesProfile RPlug:TemperatureMolar Composition Profile RPlug:。

化学工程中的反应器建模化学反应器是化学工程领域里一类非常重要的设备，用于进行化学反应以及转化反应物成为产物。

但是在真实的反应环境中，许多因素都会影响反应器的反应结果，如温度、压力、反应器几何形状等。

因此，建立反应器的数学模型是理解和优化反应器性能的关键。

反应器建模是化学工程中非常重要的部分，通过建立反应器模型，可以预测反应器的性能、优化反应器的工艺条件。

反应器建模的目的是根据反应器的物理、化学动力学、流体力学等方面的特点，建立反应器的数学模型。

这个模型可以用来分析反应器的性能，预测产物的输出率以及优化反应器的设计和操作条件。

本文将介绍反应器建模的主要方法和模型类型，并探究反应器建模在化学工程领域中的应用。

一、反应器建模的方法反应器建模的方法主要分为三种，分别是基于质量守恒定律的方法、基于物理性质的方法以及基于化学动力学的方法。

1.基于质量守恒定律的方法根据质量守恒定律，物质在反应器中的质量守恒原则是反应器建模的基础。

在建立基于质量守恒定律的反应器模型时，需要考虑流体的质量变化以及各组分的通量。

质量守恒定律模型适用于稳态反应器，但难以描述非稳态模型，因此在设计反应器过程的动态特性时，需要考虑其他的方法。

2.基于物理性质的方法基于物理性质的方法需要考虑反应过程中的多物理现象，如传热、传质和流体动力学。

在反应器的设计过程中，可以根据反应器的几何形状、物理性质和流体动力学等因素建立物理模型。

物理模型能够提供反应器的各项参数，如温度场、浓度分布和流动速度等信息。

3.基于化学动力学的方法化学反应是反应器中的核心过程，因此反应器建模需要考虑化学动力学。

化学动力学方法适用于描述反应器的动态特性。

在建立化学动力学模型时，需要考虑反应器中反应组分的反应速率常数、化学反应方程式和反应物之间的相互作用等因素。

二、反应器模型的类型在反应器建模的过程中，还需要根据反应器的操作特点，确定反应器的模型类型。

反应器模型主要分为热平衡模型、动态模型、多相模型和强度模型等。