Getting started by 4mD4ar


									         Aspen Tutorial
               ChBE 431
              Spring 2005
            Author: Joseph Zakzeski

Getting Started                2
Setup                          2
VLE diagrams                   4
Reactions                      6
The Reactor                    8
Separation: Flash Columns      11
Distillation Columns           12
Heat Exchangers                17

Getting started

Click Aspen Plus User Interface icon and enter password once the simulator finishes initializing. Save
the file as a new file name and SAVE OFTEN with different versions (ie save as design1, make a change,
then save the new design as design2. If something goes wrong, then, it’s still possible to go back to
design1 and fix problems).

The simulator will open with the following screen after the password has been entered.


First, click the Data pull-down menu then click Setup. This section allows the title, base units, and other
characteristics to be manipulated. Name the project and switch to the appropriate units. Note the toolbar
on the left part of the screen displayed in outline form. The rest of the system properties can be specified
using this toolbar by simply going down the list until all the sections have BLUE checkmarks.

                                                                                            1: Name the

                                                                                          2: Set the units

                                                                                            3. Set global

   After finishing the initial setup, click on the Components section to define the species present. Click the
   box under component ID and type in the name of the component (ie hydrogen or water). Select the type
   (typically conventional). The Tab button can be used to move to remaining sections. The simulator will
   input the component name and formula automatically if the species is present in the database. Enter all
   elements accordingly.

                                                                               1: Type in compound ID
                                                                               (ie hydrogen)

Components                                                                     2: Select type (usually

                                                                               3: Ensure that compound
                                                                               name and formula are

   After the components are entered, select Properties and Specifications on the toolbar. This section is
   where the THERMODYNAMIC MODEL is selected. First, select an appropriate thermodynamic model
   for that adequately models the components present. Using a correct thermodynamic model is crucial
   because the entire separation system will be based on it. Select the thermodynamic model in the Base
   Method section. Depending on the model chosen, the simulator should input the remaining required
   information. Enter in any necessary information if required in the appropriate section. The section is
   completed when blue checkmarks appear on the screen.

                                                                                      Select the
                                                                                      thermodynamic model
Select                                                                                in the Base Method
Specifications                                                                        Section

   VLE diagrams

   Make sure to check the VLE diagrams to make sure that the boiling points, and components of the mixtures
   match the components and that there’s no unusual occurrences. To check the VLE diagrams, after
   selecting the model, go to Tools, then Analysis, then Property, and finally Binary.

Select the analysis type (typically Txy) and the components of interest. Setup the computer to use mole
fraction based on a particular component, and under the property method select the thermodynamic model
used. Select Go to get the Txy diagram, which should be analyzed for accuracy.

                                                                        4: Select phases
1: Set Txy                                                              (typically Vapor
diagram                                                                 Liquid)

2: Select                                                               5: Set the pressure
Components                                                              (or temperature)

3: Select Basis                                                         6: Select the
and Component                                                           thermodynamic model

                                          7: Select Go

                                                                              Ensure no unusual
                                                                              behavior (like spikes)
                                                                              and that boiling points


   The next step is to enter reaction stoichiometry and chemical kinetics. Scroll down on the toolbar to the
   folder marked Reactions. Click Reactions, then click the subfolder Reactions. A new screen should
   appear. Click the New button.

Reactions                                                                     2: Name the
and then                                                                      reaction

                                                                              3: Select the
                                                                              reaction type

                                                                              4: Click OK
                                   1: Click the New

   On the next screen, hit the New button and fill in the information on the Edit Reaction Screen. Enter the
   Reactants and the appropriate coefficients (Aspen automatically places a minus sign on the reactants) along
   with the products. When the stoiciometry is correct, hit the Kinetics Tab

                                                                                  7: When finished, select
                                                                                  Kinetics Tab

                                                                                                       4: Select
                                                                                                       Reaction Type
                                                                                                       (usually kinetic)

       1: Hit New

                                                                                                       5: Enter
                          2: Enter                                                                     Products and
                          Reactant                                                                     Coefficients

                          3: Enter coefficient
                                                                                                       6: Click Next

Under kinetics, select the appropriate reaction, select the phase (ie vapor), and enter the kinetic parameters.
Do not fill in the To space. When all the parameters have been entered, select Driving Force.

                                                                      1: Select

                                                                      2: Select

                                                                      3: Enter kinetic
                                                                      Parameters (ensure
                                                                      units are correct)

                               Leave To                               4: Select
                               blank!                                 Driving force

Under driving force, enter the appropriate basis (ie partial pressure for gases) for term1. Enter the correct
coefficients based on the kinetics (typically the reactants have a 0 exponential unless they’re present in the
rate equation). For the coefficients for driving force, unless there’s a temperature dependence known, enter
0’s for all parameters. Under Term 2, the exponentials of all components is typically set at 0. Select Next.

                                                             1: Select Basis and Term

                                                             2: Set exponentials

                                                             3: Select coefficients

                                                             4: Set up Term 2 in
                                                             kinetic reaction

                                                             5: Select Next

The Reactor

At this point, the simulator is now ready for the unit operations. The best and place to start is with the
Reactor since this component is the most important in the process. On the main screen, select the Reactors
tab, click on the icon for the desired reactor (ie RPlug), and click on the screen to place the reactor. On the
far left part of the screen is a materials stream button. After placing the reactor, click on the material screen
and click on the blue arrow either entering or leaving the reactor to place the stream. Left clicking places
the streams, and right clicking “deselects” the materials button. To delete the reactor, simply right click the
icon on the screen and select the Delete Block option on the menu.

                                                           Note: Reactants enter
                                                           the Top in the Blue
                                                           arrows. Coolant streams
                                                           enter through the Red

2: Click reactor and place
                                                           1: Select Reactors tab
3: Click materials
button and place

Double click the stream entering into the reactor to specify its components. Select the appropriate
temperature and pressure along with the species present in the stream. Click next when finished.

                                                                                     5: Click Next

1: Double
click stream

                                                                                     3: Specify
2: Set Temperature
and Pressure
                                                        4: Ensure Total flow
                                                        equals Total flow

The next step is to setup the reactor block. Select Blocks on the outline on the left. Select Setup. Select
the desired reactor type (ie isothermal, adiabatic, etc.). When finished, click configuration.

                                                                   4: When finished,
1: Select                                                          configuration
                                     3: Select the
                                     Reactor type and
2: Select the                        enter necessary
Reactor and                          information
then Setup

Enter the reactor length and diameter under configuration. Aspen uses these values to calculate conversion.
Click the Reactions tab when finished

                                                               2: Select

                     1: Enter                    Ensure correct phases
                     length and                  are allowed

Under the reactions tab, simply select the reactions that are occurring in the reactor by double clicking the
reaction. Click next.

                                                                   2: Click Next

                                               1: Select

At this point, the simulator will attempt to converge the process flow diagram. Click OK and the computer
will run the simulation. To view the results of the process, double click the reactor or the stream leaving
the reactor to determine the species present.

                                                                            Species present
               1: Double                                                    in stream
               Click stream

                              Three possibilities:
                              Error (red = plant blows up)
                              Results Available with Warnings
                              (yellow = caution)
                              Results Available (blue =

Separation – Flash Columns

In order to insert separation units, select the Separators Tab and select the desired unit. Place on the
screen as was done with the reactor. Right click the stream leaving the reactor and select Reconnect
Destination. Click on the separator to connect the stream. Finally, select the materials button and create
any other necessary streams. The example used is a flash column. Double click the flash column to set the
specifications including temperature and pressure. Click next to run the simulator. (NOTE: Flash Columns
cannot be sized in ASPEN to the best of my knowledge!)

                                                                4: Click Next to
                                                                run Simulator

                                                                        3: Double click
                                                                        separator and set
  1: Select
                              2: Place
                              Separator and
                              Reconnect Stream

Distillation Columns

It’s best to start with a short-cut column before using a rigorous column in order to first acquire some
necessary information. First, click the columns tab and place the short-cut column on the screen. Connect
the stream similarly as was done with the flash column.

                                                 3: Reconnect

         2: Place short-cut
                                           1: Click
                                           Columns Tab

Double click the short-cut column to designate the specifications. Designate the column specifications (use
correlations). Click next to converge.

                                                                        3: Click Next

                                                             1: Set

                                                             2: Consider if it’s
                                                             better to have
                                                             Total or Partial

   Once the simulator converges and the system has adequately separated the components (takes some trial
   and error), double click the short-cut column again. On the outline on the left part of the screen, click on
   results and record the information. This information will aid in designing the rigorous column.

1: Double click
short-cut column

2: Click on Blocks,
The Distillation
Column, and then                                                    3: Record all
Results                                                             information

                                                      4: When satisfied,
                                                      DELETE short-cut
                                                      column (save as a new
                                                      name in case you need to
                                                      go back)

   Delete the short-cut column and replace with the RadFrac column. This column is much more rigorous
   (and also more difficult to converge). Use the information from the short-cut column to help design the
   rigorous column.

        1: Install
                                                                         2: Reconnect

   Double click the RadFrac column. Under the Configuration Tab, enter the number of stages, select the
   condenser type, distillate rate, and reflux ratio. Click the Streams tab when finished

       1: Double
       RadFrac                                                           5: Click the
                                                                         Streams Tab
         2: Enter #                                                      when finished
         of Stages

     3: Enter
     Reboiler, and

       4: Input Operating

On the Streams section, enter the feed stage and also where on the stage the stream enters (typically on
stage or above stage). Click the Pressure Tab.

  1: Input Feed
  Stage and                                                3: Click Pressure
  Convention                                               Tab

       2: Ensure phases are

In the Pressure Screen, designate the condenser pressure and click next. The Simulator should now attempt
to converge the Distillation Column. Check the outlet streams to ensure that the compositions the
conditions (Temperature and Pressure, etc.) are acceptable in each stream by double clicking the streams.

                                                                        2: Click
            1: Enter

   In order to find the important information about the column, double click the column and select Results
   Summary for condenser/reboiler duties and other information. Read through the other tabs for other
   important or necessary information.

1: Double

2: Click

                                                               3: Admire what a
                                                               sweet column this is

   In order to size the trays, on the menu on the left, click the Tray Sizing folder. On the screen that appears,
   click the New button. A Tray Sizing Section Number should appear. Simply Click OK.

1: Select
Tray Sizing

                                                                         3: Select a
                                                                         number and
                                                  2: Click New           press OK

 Aspen sizes the distillation columns on a single tray basis. Simply select a starting tray (ie 6) and an ending
 tray. Also input the tray type. This section also indicates the spacing between the trays. Once everything
 is designated, click Next to converge the PFD.

        1: Select
        Starting Tray                                             4: Click Next
        (ie 6)

                                                                  2: Select
        3: Select tray                                            Ending Tray
        type                                                      (ie 7)

 After the simulator converges, double click the distillation column. The Tray Sizing folder will now have
 a bluish color. Click the folder. On the new screen, select the box that says Results Available and hit the
 edit button.

1: Double
                                                                   3: Click

2: Click
Tray Sizing
                                                                   4: Click Edit
(now blue)

           On the new screen, click the results tab. The column diameter is listed on this menu.

                                                               1: Click
                                                               Results Tab

                                                               2: Record

 Heat Exchangers

 To insert a heat exchanger, click on the Heat Exchanger Tab and place the desired heat exchanger on the
 screen (HeatX is the rigorous exchanger. Use this type rather than starting with a shortcut exchanger). The
 HeatX exchanger requires both the shell side and tube side streams. If cooling, for example, without using
 heat integration, simply designate the stream a water stream at the desired temperature by double clicking
 the stream and filling in the appropriate information.

       1: Select Heat
       Exchangers Tab

                                                                   4: Double click
     2: Place Heat X               3: Connect Material             unspecified
     (rotate if desired)           Streams                         Stream

For the unspecified stream, just enter the desired temperatures and flowrates, then close the box

                                                                            4: Close the box

                                                              1: Enter

                                                              2: Enter

                                                              3: Enter species
                                                              and total flowrate

Double click the heat exchanger to specify the parameters. A shortcut calculation should suffice. Specify
the stream conditions (ie, hot stream outlet temperature, cold stream outlet temperature), and ensure that the
minimum approach temperature is AT LEAST 10K. When finished at this screen, select pressure drop.

                                                                  3: Click Pressure
       1: Enter

       2: Ensure minimum
       approach temperature
       at least 10K

Specify the pressure drop that occurs in both the hot and the cold side of the exchanger. Click U Methods.

  1: Designate
  Hot or Cold
                                                            3: Click U

  2: Specify
  outlet pressure

Select and appropriate U term for the system (depending on if the species are both liquids, liquid/gas,
condensing gas, etc.) Click next to converge PFD.

                                           2: click Next

                1: Select
                Appropriate U
                (watch units!)

Double click the Heat Exchanger. Click the Thermal Results listing on the Outline, and click Exchanger
Details to find the heat duty and exchanger area. Make sure to check the streams leaving and entering the
exchanger to ensure appropriate conditions.

  1: Double
  Click Heat

                                                               3: Click

                                                               4: Note
                                                               Duty, Area,
       2: Click Thermal
                                                               U, and other
       Results                                                 info

                                        5: Check actual streams to
                                        ensure appropriate conditions

You should now have enough of the basic tools to design a chemical system using ASPEN. Several other
unit operations are available and can be placed and used similarly. Make sure to save often when making
changes under new file names because it’s easier to make changes to a working diagram than it is to fix and
make changes to one that doesn’t work. Good luck!


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