Aspen Tutorial

Terry A. Ring

ChEN 4253

Process Simulation Software

• Steady State Process Simulation– AspenPlus– ProMax– ChemCad– Hysis– HySim– ProSim– CADSim– OLI Process Simulator– KemSimp– Chemical Workbench Code– Ascend IV

• Dynamic Process Simulation– Aspen Dynamics– CADSim – Simulation Solutions, Inc.

Types of Simulators

• ProMax• Equation Based

– Solves block by block

• Aspen• Puts all equations into

one Matrix equation– Solves all Mass and

Energy Balances at once

Basic Elements of a Simulation Program

Towler and Sinnott , “Chemical Engineering Design : Principles , Practice, Economics of Plant and Process Design” , Elsevier (2008)

**

* - Reaction Engineering, Mass Transfer, Heat Transfer, Fluid Mechanics

Numerical Methods

Thermodynamics

Thermodynamics

Other Subjects : Solid Mechanics, Manufacturing ScienceEconomics

Aspen

• Aspects of Aspen

– Next Button

– Many units that perform a given function• Degrees of Freedom are chosen for you

– Setup for kinetic reactions are tricky

– Accounts for particle sizes• Simple block models

– Automatic Plant Costing (Aspen Economics)

Steps to Run

• Aspen (Left Hand Bar)– Wiring up Process– Title– Components– Thermopackage– Process Flow Sheet

• Feed Stream• Unit Specifications

– Fixed degrees of freedom

– Run– Results– Report

ThermoPackage Choice

• Questions for ThermoPackage Choice

• Are the components? – Polar– Non-Polar

• System Pressures?– P< 10 atm - ideal gas

• Interaction Parameters Available?

Eric Carlson’s Recommendations

E?

R?

P?

Polar

Real

Electrolyte

Pseudo & Real

Vacuum

Non-electrolyte

Braun K-10 or ideal

Chao-Seader,Grayson-Streed or Braun K-10

Peng-Robinson,Redlich-Kwong-Soave,Lee-Kesler-Plocker

Electrolyte NRTLOr Pizer

See Figure 2Figure 1

Polarity

R?Real or pseudocomponents

P? Pressure

E? Electrolytes

All Non-polar

P?

ij?

ij?

LL?

(See alsoFigure 3)

P < 10 bar

P > 10 bar

PSRKPR or SRK with MHV2

Schwartentruber-RenonPR or SRK with WSPR or SRK with MHV2

UNIFAC and its extensions

UNIFAC LLE

PolarNon-electrolytes

No

Yes

Yes

LL?No

No

Yes

Yes

No

WILSON, NRTL,UNIQUAC and their variances

NRTL, UNIQUACand their variances

LL? Liquid/Liquid

P? Pressure

ij? Interaction Parameters Available

Figure 2

VAP?

DP?Yes

NoWilson, NRTL,UNIQUAC, or UNIFAC* with ideal Gas or RK EOS

Wilson NRTLUNIQUACUNIFAC

Hexamers

DimersWilson, NRTL, UNIQUAC, UNIFAC with Hayden O’Connell or Northnagel EOS

Wilson, NRTL, UNIQUAC, or UNIFAC with special EOS for Hexamers

VAP? Vapor Phase Association

Degrees of PolymerizatiomDP?UNIFAC* and its Extensions

Figure 3

Bob Seader’s Recommendations

Bob Seader’s Recommendations

LG?

E?

PC?

HC?

Yes

Yes

No

Yes

See Figure 5

Special: e.g., Sour Water (NH3, CO2, H2S, H2O) Aqueous amine solution with CO2 and H2S

PC?

No

Modified NRTL

No

No

PSRKYes

NoSee Figure 5

See Figure 6

HC? Hydrocarbons

LG? Light gases

PC? Organic Polar Compound

E? Electrolyte

Yes

Figure 4

Figure 5

T?

P?

BP?

Narrow or wide

PR

LKP

Cryogenic

Non- Cryogenic

Critical

Non-Critical

SRK, PR

PR, BWRS

Very wide

HC and/ or LG

P? Pressure region

T? Temperature region

BP? Boiling point range of compound

Figure 6

PPS?

BIP?

Available

UNIFAC

Yes

NoWilson

NRTL, UNIQUAC

Not Available

PC with HC

PPS?Possible PhaseSplitting

BIP? Binary Interaction Parameters

Hyprotech Recommendations

Model Pure Binary Mixture VLE VLLE Notes

EOS (Equation of State)

SRK (Soave RedlichKwong) ● ● ● ● ●

Gas Processing with No Methanol, Refinery Distillation

Peng-Robinson● ● ● ● ●

Gas Processing with No Methanol

SRK Polar● ● ● ● ●

Gas Processing with Methanol or NMP

Peng-Robinson Polar ● ● ● ● ●

Gas Processing with Methanol or NMP

Lee-Kesler

● ● ● ● Light Hydrocarbon Systems with H2S and CO2, No 2nd Liquid Phase

Tillner-Roth and Friend NH3 + H2O

● ● ●

Ammonia Absorption Refrigeration, Ammonia and/or Water Only

ProMax Guidance(5 more pages like this)

Problem-1

• Problem 5.12• Alternatives in preparing a feed. A

process under design requires that 100 lbmol/hr of toluene at 70F and 20 psia be brought to 450 F and 75 psia.

• Flow sheets using Peng-Robinson– Boil-Superheat-Compress– Pump to 75 psi-Boil-Superheat– Which process uses the most energy?

Design Spec

– What Then How (WtH)• What do I want to specify?• What do I want to vary to control it?

Which System has the most Energy?

• Moving from To, Po to Tf, Pf

– STATE PROPERTY

• Enthalpy change is the same if the end points are the same.

• Why is Boil then Compress not suggested? Heuristic 43

Problem -2

• Use Gibbs Minimization reactor in Aspen to determine the products of reaction at 10 atm and 200 C.

• Feed equimolar in CO and H2

)(

2

22

32

sCOHHCO

OHCHHCO

Sensitivity Analysis

• Produces Table of Results using a Do Loop to vary one (or more variables)

• What Then How

Problem 3

• Use Equilibrium Reactor to determine reactor conversion for methanol reaction at 10 atm and 200C

• Use sensitivity analysis to determine reactor conversion at a suite of temperatures

OHCHHCO 322

Problem -4

• Determine the resulting equilibrium at 10 atm and 200 C using an equilibrium reactor in Aspen with both of the reactions listed.

)(

2

22

32

sCOHHCO

OHCHHCO

Problem 5

– Vapor-Liquid Equilibrium• 40mole% Ethanol – water

Problem 6

• Liquid-Liquid Equilibria– Polar - polar

Problem 7

• Liquid-Liquid Equilibria– Polar - non-polar

Problem 8

• Multiple component phase equilibria– Methane – 0.1 mole fraction– Ethane – 0.2– Propane- 0.3– Butane- 0.3– Methyl ethyl keytone -0.1

– 10 atm, 10°C– Use Ideal and Peng Robinson Thermo Pkg.

• Compare results

Example-9

• Distillation/Flash

• Methanol – Water– 100 lbmole/hr

• Flash at 90C, 1 atm• Distillation

– R=2– BoilUp Ratio=3