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Aspen Plus Setup for a PumpPipe Flow Process Problem _Ex 63 pg

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Aspen Plus Setup for a PumpPipe Flow Process Problem _Ex 63 pg Powered By Docstoc
					Problem:         (Ex. 6.3 pg 193 de Nevers)

     Two reservoirs are connected by 2000 ft of 3-in schedule 40
pipe (carbon steel). (See diagram below) Water is to be
pumped at a rate of 200 gallons per minute from one reservoir to
the other. An Aspen Plus Simulation will be created to find the
required pump power and the required pump pressure rise for
this scenario.



                          Same Level




                                 2000 ft
                          3-in    Schedule 40




                 PUMP
Aspen Plus
             Setup for Pump/Pipe Flow Simulation


                                         Click „ok‟

                                         Another window will appear
                                         indicating that the connection is
                                         established.

                                         Click „ok‟




                                       Click on the diamond button next to
                                       the “Create a new run” option. Then
                                       click ok.




                                     In this pump/pipe flow simulation, aspen
                                     plus will calculate the required pump
                                     pressure rise and pump power.



                                     Select general with metric units for the
                                     application type and flowsheet
                                     simulation for the run type. To do this,
                                     click on the box and a list of options will
                                     appear. Select the appropriate choice.
                                     Click ok when finished.
  To start the Pump/Pipe flow
  simulation, create a feed arrow as
  shown. To create the pump, click on
  the Pump/Comp selection in the Type
  menu and the Pump selection in the
  Model menu. Also, select the ICON1
  option in the Icon menu.

  When the ID box appears, label the
  pump “PUMP-1.”




To choose the pipe, select the Pipe/Valve
option in the Type menu and the Pipe
option in the Model menu. Choose the
H-PIPE selection from the Icon menu.

When the ID box appears after creating
the pipe, name it “P-1.”
  Now create a product arrow. Connect
  everything together as shown on the left.
  Label the stream from the feed arrow to
  the pump as “FEED,” and the stream
  from the pump to the pipe as “OUT.”
  Then label the stream from the pipe to
  the product arrow as “PROD.”

  When completed click on the next
  button.




Click on “ok”.
This screen will appear next. Click on
the title field and give this project a
title. Also, in the flow/frac options,
select the nomoleflow, and stdvolflow,
options by right clicking on the
appropriate boxes. For example, to
select the nomoleflow option, right
click on the text “MOLEFLOW.” Left
click on the molefrac option.


Also at the bottom of the window,
right click on the Flow-Basis box and
select the STDVOL option.
Your screen should match the diagram
on the left. Click on the next box to
continue.




  Only water will be entered here. In the
  column labeled component name, type
  water in the first space. Press enter and
  the formula and type columns will fill in
  with the appropriate data. Then on the
  same row of the water data, click on the
  comp ID column. You will need to
  name the component with a short,
  concise name. This name will appear in
  the report generated by Aspen so use an
  easily recognizable name. Click the next
  box.
In this window, only one parameter
needs to be changed. Right click in the
box labeled Opsetname and choose
NRTL from the menu. Click the next
box to continue.




Click on the ok button




Enter the data here for the inlet stream
(FEED). This stream contains liquid
water, so select 50 deg F for the temp.
and 14.7 psi for the pressure.

In the box labeled H2O, enter the
value 200. Notice the units of the
values you just entered in the box
labeled composition basis. These
units can be changed by first right
clicking on the box and selecting the
appropriate units from the options.
For this example select GAL/MIN.
Click next.
The information about the pipe will be
entered in here. First, enter in the length
of pipe, 2000 ft, and enter in the type of
material. Right click on the Material box
and select carbon-steel. Then right click
on the Schedule box and select 40. Next,
right click on the Nom-Diam box and
select 3-IN. Note how the In-Diam box
automatically fills in. Finally, in the Type
box under the Thermal Information, right
click and select the ADIABATIC option.

Click next.




      This window shows that all of
      the required forms are
      complete. Incomplete forms
      would appear in red.
      Click next.
     In the Pres box, enter 100. This
     value is only a guess. Eventually,
     this value will be used in an
     iteration to determine the pressure
     drop across the pump.




Click cancel. More input is to be entered.




     Now we are going to have Aspen
     Plus iterate to find the pressure at the
     pump outlet.

     We are going to use the design –spec
     option. Please refer to the design-
     spec manual for further detail.

     Go to the Forms menu at the top of
     the page. Select Flowsheet Options
     and then the Design-Spec option.
Click on the create button.




This box will appear with the default
ID of “DS-1.” This default value is
appropriate for this example. Click
„ok.‟




The data for the Design-Spec
function will now be entered.
Click next.
This page is used to specify the outlet
pressure. Because both reservoirs in
the example problem are at atmospheric
pressure, we can use one of these
known values to find the pump outlet
pressure. For this example we will use
the outlet pressure.

In the Varname box, enter in the
name „PRES.‟ Then right click on
the Vartype box and select the
„STREAM-VAR.‟ Next, right click
on the Stream box and select
„PROD.‟ Press enter and the
Substream box will automatically
select „MIXED.‟ Finally, right click
on the Variable box and select
„PRES.”
Click next to continue.




  Now we will setup Aspen Plus to
  find the pump outlet pressure.

  Right click on the Spec box and
  select „PRES.‟ Then click on Target
  box and enter 14.7; click on the
  Tolerance box and enter 0.01.

   Right click on the Vartype box and
  select „BLOCK-VAR.‟ Next, in the
  Block box, right click and select
  „PUMP-1.‟ Also, right click in the
  Variable box and select the „PRES‟
  option; the Sentence box will
  automatically fill in. Finally, enter
  the manipulated variable limits. In
  the Lower box enter 14.7 and enter
  in the Upper box 200.
  Click next.
 This window indicates that all
 required input is complete,
 otherwise some of the items would
 appear in red.
 Click next.




Click on „ok.‟




Click on the „Results.‟




This screen shows that the
calculations were completed
normally. If the calculations were
completed with errors, click on the
status to try to determine the source
of error.

Click on the double right arrows at
the top of the page. This will bring
you to a results page.
These are the results from the simulation.
Click on the right double arrow to view
the additional results. To view the
required pump power and the pump
pressure rise, click on the right double
arrow until the (Pump.Results) appears.




   This page displays the required
   horsepower and pressure rise for the
   pump.

   The calculated power was 8.9 hp and
   the pressure rise was 77.12 psi.

				
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