Conceptual Demo Guide

8/12/2019 Conceptual Demo Guide

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2013 Aspen Technology, Inc. All rights reserved

Conceptual Solids Modelsin Aspen Plus V8.4Guide to the Demo

Aspen Technology

Burlington, MA

2013


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2013 Aspen Technology, Inc. All rights reserved | 2

Conceptual Solids Models

Conceptual models ease learning experience for new solidsusers such as process engineers

Not necessary to have in-depth knowledge of particletechnology or the specific apparatus

More experienced solids users can use conceptual models to

sketch the solids processing section before adding moredetails (if necessary)

Conceptual model can be changed to a more rigorous modelwithout reconnecting streams

Conceptual models allow for better collaboration betweenprocess engineers and particle scientists

Process engineer can include solids sections in the overallflowsheet using conceptual solids models

Particle scientist can work with the process engineer to makethe model more rigorous if necessary


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Conceptual solids models enable everybody tomodel solids without being a solids expert

Conceptual(process engineer)

Rigorous Equipment Model(solids expert)

3 parameters todefine a decanter


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Functionality of conceptual models Comminution/Formulation

(Crusher, Granulator, Crystallizer)

Specify outlet PSD

Solid Separators(Centrifuge, Cyclone, ESP, Scrubber etc.)

Specify Desired Split

Dryers

Specify Outlet Moisture

Crystallizer Crusher Granulator Flash 2


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Example:Aspen Plus Model Bisphenol A (BPA) Production

Demo Focus: BPAPurification Section

Large, mostly fluid process

Includes several solids unit operations and a purificationsection at the end of the process


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BPA Purification Section of the Process

BPA is crystallized intoluene to remove residualphenol. The BPA crystalsare dried with nitrogen toremove toluene. The finalproduct is melted and sentto a heated storage tank


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Open the file Conceptual Model Example

Isolated purificationsection from the

larger BPA Process



Conceptual Modeling Example

Dryer isdescribed by a

rigorous model

Optimizer is used toadjust the nitrogen

flow to reach a purityof 99.9%

Conceptualmodel is used for

the centrifuge



Conceptual Model of the Decanter

Open the input form of centrifuge S502

conceptual model is used for the centrifuge

split of solids and liquid is described by split factors

solids separation is modeled by a separation curve based onparticles settling velocity and a given separation sharpness



Calculation Results

Run the example and show the results for centrifuge S502

show the separation curve (switch to log. X-axis)

model is more than just a splitter model, describes separationbased on settling velocity

Tip: Change the scale ofthe X-axis to log to get abetter resolution



Calculation Results

Custom tables shows

Necessary dry gas flowrate (determine by theoptimizer)

Power and utility costsfor the blower (K505)

Duty and utility costsfor the nitrogen heater(E504)

Duty and utility costsfor the exhaust heater(E503)

Total process utility cost

Total process utility cost in the base case are 32.30 $/hr(~283.5 K$/HR)



Objective

Goals

Necessary dry gas flow rate (determine by the optimizer)

BPA must by purified

reduce energy demand for the dryer and with this theprocess utility costs

Constraints Throughput must not be changed

Purity of the product must be minimum 99.9%

Idea

Investigate the influence of the moisture content from thesolids stream leaving the centrifuge on the utility costs



Set up a Sensitivity Analysis

Create a sensitivity case to investigate the influence of the

solids outlet moisture from the centrifuge on the utility costs

Click New

Enter ID and clickOK

1

23

Position vary input form onthe left of your screen

4Open input form of centrifuge S502 and positionthe form right on the screen

5

Use right click and new vertical tab.


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6

drag & drop

Drag and drop thefraction of liquid toliquid outlet to themanipulatedvariable section

7

Varyfraction ofliquid to liquid

outlet from 0.4 to0.6 (10 points)

Vary


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8

drag & drop

Drag and drop variables from thecustom table into the measuredvariables are- E504 Utility cost (heater before dryer)- E503 Utility costs (heater after dryer)- E505 Power costs (blower)

Rename variables E504, E505,

Blower in the define tab

9

Select tabulated variables and

click the Fill Variables button

Define


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Run & Review Sensitivity Results

Run the model andreview the results

Reduced outlet solidsmoisture content fromthe centrifuge leads toreduced utility costs forthe heaters and the

blower (conceptualmodel predicts a linearrelationship)


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Objective: Gain furtherunderstanding of how theoperating conditions of thedecanter influences theutility costs of the process

Solution: Convert the model to

rigorous

Conduct a sensitivitystudy using the rigorous

model of the decanter

Reduce Energy Costs


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Switch to Equipment Model

Switch the centrifuge (block S502) to the equipment model

Not necessary to reconnect streams

Select decanterequipment model


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Select classification and deliquoring model

(already pre-defined in the example)


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Enter model and geometryparameter (already pre-defined in the example)


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Hide Sensitivity

Hide sensitivity case

Only deactivating the sensitivity case will lead to an error duringinput translation since the varied variable is no longer exists

Want to reuse the sensitivity case later on


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Run Simulation with the rigorous model

Run simulation and review separation efficiency curve if S502

Tip: Change the scale ofthe X-axis to log to get abetter resolution


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Comparison of Results from Conceptual andEquipment Model

Equipment models predicts a slightly different separation curve

(based on given geometry and operating conditions)leads to different dry gas flow and therefore slightly different utility costs

Results with equipment model

Results with conceptual model


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Change Sensitivity Case

Reveal the defined sensitivity task

Use sensitivity analysis to determine how the rpm of thedecanter influence the utility costs of the process

1


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Change Sensitivity Case

2Open sensitivityinput form 3

Position vary input form on the left ofyour screen and delete defined variable

4Open input form of centrifuge S502 and position theform right on the screen


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5

drag & drop

Drag and drop thedrum rotary speedto the manipulatedvariable section

6

Vary drum rotaryspeed from 300 to

1200 rpm (5 points)

Remark: No need to make furtherchanges to the sensitivity case, sincemeasured variables etc. have beendefined already earlier


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Sensitivity Case - Results

Run Model &Review results

Increased rotary speedof the decanter leadsto reduced utility costsfor the heaters and theblower (equipment

model predicts a non-linear relationship)


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Dryer/Centrifuge Optimization Results

Centrifuge Rotation Residual Moisture Gas to Dryer Blower Power

Gas Heater Duty Condenser Duty Operating Cost

An increase of the centrifuge rotary speed from 300 rpm to 1200 rpm would: Decrease the solids outlet moisture by ~56% Decrease the drying agent flow by ~27% Decrease the process utility costs by ~215


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Summary

Use conceptual models togain an understanding ofwhich unit operations havethe largest impact on theenergy demand and utility

costs of a larger process Convert those units from

conceptual to equipmentmodels to further investigatehow design or operating

conditions affect energydemands.

Demo Focus: BPA Purification Section

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Conceptual Demo Guide

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