ASPEN高級培訓課件解析

1、Introduction to Equation Oriented (EO) ModelingLesson Objectives比較聯(lián)立方程求解 (EO)和序貫?zāi)K求解 (SM)確定產(chǎn)品流股PRODUCT 組成可用求解方法:序貫?zāi)K法 (SM)聯(lián)立方程法 (EO)組合法 (of SM and EO)A Typical Simulation ProblemREACTORFEEDRECYCLEREAC-OUTCOOLCOOL-OUTSEPPRODUCTEquation Oriented versus Sequential Modular序貫?zāi)K法(SM)求解是按照流程順序逐個計算每一個模塊,我們要

2、提供進料條件，計算得到每個模塊的產(chǎn)品流股。 如果流程中出現(xiàn)循環(huán)就需要進行迭代. 聯(lián)立方程求解所有方程同時求解. Why Use Equation Oriented Modeling?聯(lián)立方程求解策略尤其適合下列模擬過程:熱整合過程多循環(huán)流程多設(shè)計規(guī)定優(yōu)化數(shù)據(jù)協(xié)調(diào)和參數(shù)預(yù)估Highly Heat-Integrated ProcessesCrude Unit With Preheat TrainSM Mode: Invalid hot T spec in HX02Single tear stream Q106EO Mode:Converges in one iteration (19 sec)Hi

3、ghly Recycled ProcessesEthylene PlantSM Mode:Tear streams: PRBTMS, DECRFD Fails to converge: PFRAC and QUENCH not in mass balanceEO Mode:Converges in three iterations (11 sec)Processes with Design SpecificationsFCC Fractionator with Absorption-Stripping SystemSM Mode: Three convergence loops: one te

4、ar stream + two design specsTear stream fails to convergeEO Mode:Converges in four iterations (45 sec)Process OptimizationAmmonia PlantSM Mode: Maximize PRODUCT stream flow; Vary 11 parameters; 6 ConstraintsTakes 7 minutes (314 passes) to converge tear stream and Opt blockEO Mode: Maximize PRODNH3.B

5、LK.PRODNH3; Boundaries for 18 variablesConverges in five iterations (0.47 sec)Process Model Tuning估算板效率SM Mode:Point data set of flowsTwo Calculator blocks requiredEstimated value = 0.314826EO Mode:11 measurements; enter Plant valuesMinimize Sum of squares function of calculated offsetsCOLUMN.BLK.EF

6、F_1 =0.356297Plant measurements include feed flow, temperatures, and product compositionsEquation Oriented Modeling in Aspen Plus聯(lián)立方程求解步驟繪制模擬流程。定義組分，選擇物性方法。提供進料流股和設(shè)備的操作參數(shù)。用SM計算方法進行變量初始化。Equation Oriented Initialization and Solution聯(lián)立方程求解策略：所用變量的初值最好靠近結(jié)果。 進行聯(lián)立方程求解之前要用序貫?zāi)K求解進行初始化。 SM 求解結(jié)果可以不收斂 流程中的每個模

7、塊至少要計算一次. SM Strategy Solution Modes用SM求解策略, Aspen Plus 是單一運行模式1. Simulation: 輸入條件和模型參數(shù)固定，沒有自由度。大多數(shù)情況可以方便求解。對于下列情況求解困難且耗時，例如： Data-Fit 工具可以進行參數(shù)預(yù)估和數(shù)據(jù)協(xié)調(diào). 優(yōu)化工況EO Strategy Solution Modes (1) EO 求解有四種模式:1.Simulation: 沒有自由度，提供進料條件和操作參數(shù)計算產(chǎn)品結(jié)果。Optimization: 有一定的自由度，需要構(gòu)建目標函數(shù)。3. Parameter Estimation: 沒有自由度，進料

8、和產(chǎn)品條件固定估算模型參數(shù)，對應(yīng)每個估算參數(shù)需提供測量參數(shù)。Reconciliation: 有自由度，需用模型計算結(jié)果與測量變量構(gòu)建目標函數(shù)，并使其方差和最小化。EO Variable Definitions變量屬性：Fixed: 固定變量。Free: 計算變量。Degree of Freedom (DOF): 有一定自由度變量。EO Variable Specifications (1)變量在不同運算模式下屬性:There are other specifications for Measured, Parameterized, Reconciled, and Independent var

9、iables in the four modes. Refer to Appendix A for a complete list.SpecificationOptimizedCalculatedOptimizationDOFFreeFixedSimulationFixedFreeFixedConstantEO Variable Specifications (2)四種運算模式變量屬性定義:固定變量(specification = Constant)計算變量(specification = Calculated)Net Specification (1)自由度定義:NSPEC = NVAR N

10、EQN NFIX NDOFWhere:NSPEC=net specificationNVAR=number of variablesNEQN=number of equationsNFIX=number of fixed variablesNDOF=number of degree-of-freedom variablesNet Specification (2)如果NSPEC是零，則 沒有自由度,矩陣為方陣，有唯一解。 有DOF類型變量,需要構(gòu)建目標函數(shù)。如果NSPEC是大于零, 有多個解。如果NSPEC是小于零, 無解。 Equation-Oriented Supported Blocks

11、SM 和 EO支持模型:Analyzer HeatX RStoicCompr HXFlux RYieldDecanterMeasurement SelectorDuplMixer SepExtractMult Sep2Flash2 PetroFrac RCSTRFlash3 Stream FSplit Pump REquil HeaterRadFrac RPlug Valve User3 EO不支持模型:Aerotran MCompr BatchFrac MHeatX RGibbsDistl MultiFrac DSTWU Pipe RateFrac Pipeline SCFracHetran

12、 RBatch HTRI-IST User/User2Calculator supported but no automatic EO mapping聯(lián)立方程不支持下列模型功能:嚴格三相計算RadFrac 除外固體電解質(zhì)過程真實組分 流程級設(shè)計規(guī)定優(yōu)化約束靈敏度分析Synchronizing the EO FlowsheetSM模式運行切換EO模式變量總表模塊變量表進料流股變量表Viewing the EO Variables(1)Viewing the EO Variables(2)異丙苯流程EO 變更量表Viewing the EO Variables(2)變量命名blockid.blk.

13、variableid.descriptionblockid 模塊名variableid 變量名variableid is streamname.STR與模塊相關(guān)流股變量 description 描述Viewing the EO Variables(2)舉例EO Configuration Defaults計算采用國際單位制組成用摩爾分數(shù)（）嚴格核算模型 RadFrac 所有流率用摩爾流量SM和 EO 連接方程Flowsheet View (SM View)Internal EO ViewBlockB1BlockB2S1S2S3BlockB1BlockB2S1S2 (as Block B1 ou

14、tlets)S2(as Block B2 inlets)S3Connection Equations Use the NRTL-RK Property Method40 stagesFeed stage 24Total condenserTop stage pressure = 16.1 psiaPressure drop per stage = 0.1 psiDistillate flowrate = 1245 lbmol/hrMolar reflux ratio = 1.3EO變量練習(1)63.2 wt% Water 36.8 wt% Methanol Flow = 120000 lb/

15、hrPressure 18 psiaSaturated liquidCOLUMNFEEDDISTBTMS產(chǎn)生EO變量表完成如下任務(wù):創(chuàng)建新變量表，使其包含塔的熱負荷以及產(chǎn)品流股流率。觀察變量 COLUMN.FEED.STR.PRES 和變量EED.BLK.PRES的區(qū)別?察看每個平衡級變量數(shù)存文件 RAD-eovars.BKPChanging Variable Attributes (1)在 SM 和EO 求解模式,我們經(jīng)常會改變變量的屬性. 在SM, 用設(shè)計規(guī)定（Design-Spec）實現(xiàn)。在 EO, 可以在EO變量表修改其屬性實現(xiàn)。 Spec Groups推薦用Spec Groups來修

16、改變量的屬性。Spec Groups 有三個不同級別：頂層EO Configuration表每個層次 EO Configuration 表每個模塊EO Configuration 表Steps for Changing Specifications1. 新建Spec group：選擇一組變量交換其屬性。2 . 固定變量提供目標值。3 . 運行EO 模式求解。REACTORFEEDRECYCLEREAC-OUTCOOLCOOL-OUTSEPPRODUCTChanging Specifications Example (2)Save as filename: EOINPUT.BKP組分CUMENE

17、在產(chǎn)品流股中摩爾分數(shù)達到98%，求冷卻器出口溫度。: 調(diào)節(jié)變量?測量變量? Cooler outlet temperatureConstantCalculated Mole fraction of cumene in stream PRODUCT = 0.98Calculated Constant Pairs保持其自由度不變： Before Aftervariableid1Calculated variableid2Constant ConstantCalculatedControl Panel Messages for EO (1)The information reported for e

18、ach iteration includes:Residual Convergence FunctionThis is a measure of how close the equations are to being solved. If after one iteration, the Residual Convergence Function is less than 1.E-6, the problem is converged. If not, iterations continue until this value is met.Objective Convergence Func

19、tion and Objective Function ValueRelevant mainly for the EO Optimization and Reconciliation solution modes, these parameters show how close the objective function is to the final value and the calculated value of the user-defined objective function. If you have defined an objective function for Opti

20、mization, Reconciliation, or Parameter Estimation, but are solving in the EO Simulation mode, these values will still be printed. Otherwise, values of zero are printed in the EO Simulation mode.Control Panel Messages for EO (2)Overall Non-linearity RatioThis is a measure of the non-linearity of the

21、overall problem. The closer the Non-linearity Ratio is to 1.0, the more linear the problem. A negative value indicates that the problem behaves in the opposite of what is expected. Near the solution, as step sizes decrease, this value should approach 1.0.Model Non-linearity RatioThis is the Non-line

22、arity Ratio for the worst model.Worst ModelThis is the model whose non-linearity is furthest in absolute value from 1.0.Re-Running Simulations in EO Mode (2)Re-synchronizationWhen you make a change to the SM simulation and attempt to re-run the file, you will be prompted to synchronize the flowsheet

23、.Examples:Changing an input fieldAdding a block or stream to the flowsheetCreating flowsheet sectionsSave as filename: RAD-eoinput.BKPH2O mole fraction = 0.999Equation Oriented Modeling Workshop (2)Vary flowCOLUMNFEEDDISTBTMSCalculated OVHD flowrate (lbmol/hr) _ Duties (MMBtu/hr): Condenser _ Reboil

24、erHeat IntegrationLesson ObjectivesUse Heater and HXFlux models to model the utility side of a heat exchanger.Heat Integration利用熱整合模型包括:用Heater模型模擬熱換器用HXFlux模型計算熱傳遞用 Connections 實現(xiàn)兩個EO變量連接我們將用 HXFlux/Heater 來計算公用工程的進口條件。Heater/HXFlux Combination用 HXFlux/Heater 模擬塔頂冷凝器。 Steps for Setting up Heat Inte

25、gration用Heater 模擬公用工程側(cè)換熱用Spec Group 計算移走工藝側(cè)放熱需要的公用工程流量。用HXFlux 計算熱傳遞.計算公用工程流股的出口條件。用EO Connections傳遞HXFluxr和Heate 的計算信息。Rigorous Heat TransferAspen Plus offers two unit operations to rigorously model heat transfer, HeatX and HXFlux. The preference is HXFlux since you avoid tearing the material strea

26、m. This makes solving efficient. HXFlux allows you to reference EO Variables for stream temperatures (especially helpful when referencing stage temperatures).HXFlux Model用于計算熱傳遞可用于對流傳熱或輻射傳熱流體流動方式可以是并流或逆流?？梢詰?yīng)用熱流股或參考熱流股可以自動連接流股溫度或應(yīng)用EO變量HXFlux Model ExampleREACTORFEEDRECYCLEREAC-OUTCOOLCOOL-OUTSEPUTILI

27、TYOUTINPRODUCTQCSave as filename:EOHEATER.BKPCONDUAHXFLUXQHXFlux Model Example公用工程選用丙烯，初始條件：200Psi飽和液相，流量20,000lb/hr。公用工程側(cè)換熱器不考慮壓降。熱交換器總傳熱系數(shù) U = 125 Btu/hrft2F換熱面積 Area = 50 ft2Connection Processing (1)Connections 是在系統(tǒng)中增加兩個變量，一個方程，以確保有相同的計算結(jié)果。Connection 自動調(diào)整變量的屬性以適應(yīng)自由度的要求。對于每一個 connection, 如果不能滿足自由度

28、的要求，此 connection 將被失活狀態(tài)。Convention 建立下面方程: 目的地Destination =來源 SourceConnection Processing (2)Objective: Add a simple heat integration. Start with the file RAD-eoinput.BKP.Heat Integration Workshop (1)CVAPQC280,000 lb/hr saturated liquid propylene at 22 psia - Use Heater and HXFlux blocks to simulate

29、 the column condenser. What are the final process conditions of the refrigerant stream?DP=0CONDUAHXFLUXQCOLUMNFEEDDISTBTMSCOUTCINSave as filename: RAD-EOHEAT.BKPHeat Integration Workshop (2)Part A Define a Heater with no pressure drop to represent the utility side of the condenser.Use these conditio

30、ns as the starting point for the refrigerant stream: 280,000 lb/hr saturated liquid propylene at 22 psia.Create a Spec group that will completely vaporize the utility stream and calculate the required CIN feed rate.Create two component groups and assign to two flowsheet sections to control the compo

31、nents used in each section. Determine the number of non-zeros.Calculated CIN stream flowrate (lb/hr) _Heat Integration Workshop (3)Part BDefine a HXFlux model and heat-integrate the utility stream and the column. Use stage 2 temperature as the Inlet hot stream TEnter 300 Btu/hr ft2F for U and 1000 f

32、t2 for areaCreate a Spec group to fix the heater outlet temperature and calculate the inlet pressure. Define a connection to connect the cold outlet temperatures for the CVAP and CONDUA blocks.Final CIN stream conditions: Flowrate (lb/hr)_ Temperature (F) _Pressure (psi) _Equation Oriented OptimizationLesson ObjectivesCreate a simple