Embed Size (px)
Citation preview
OLI Simulation Conference 2014
Process Safety Study Using Aspen/OLI
▬
Inadvertent Mixing of Electrolyte Raw Materials
In Storage Tanks
® TM The DOW Diamond is a Trademark of The Dow
Chemical Company (“Dow”) or an affiliated company of Dow.
David Kolesar The Dow Chemical Company
October 2014
Background / Objective
We All Know What Happens If Sulfuric Acid Accidentally Gets
Pumped Into A Caustic Tank.
But What Happens If, Say, Methacrylic Acid Were Pumped
Into An Aqueous Ammonia Tank (Weak Acids and Bases).
These Are Just The Questions That Dow Process Safety Was
Looking Into And Needed A Means To Evaluate Them.
Decision Was Made To Build A Dynamic Simulation.
D Kolesar October 2014 OLI Simulation Conference 2014
Initial Modeling Attempt With Aspen Dynamics
D Kolesar October 2014 OLI Simulation Conference 2014
Initial Modeling Attempt With Aspen Dynamics
Worked Well But Many Components and
Chemistry Were Missing
D Kolesar October 2014 OLI Simulation Conference 2014
Next Attempt: Aspen Dynamics With OLI Chemistry & Properties
D Kolesar October 2014 OLI Simulation Conference 2014
Dynamic Results of Methacrylic Acid into Ammonia Tank
D Kolesar October 2014 OLI Simulation Conference 2014
With Many Tanks to Evaluate Needed A Tool for the Non-Modeler
- Aspen Simulation Workbook -
Many, Many Plants and Tanks (100’s) To run
But, Not Good Use of Modeler’s Time
The plan - Embed the Aspen Dynamics
Flowsheet In Aspen Simulation Workbook (Excel
Interface For Aspen Simulators)
Provides Tool for Process Safety Personnel to
Use And Run A Multitude Of Cases
D Kolesar October 2014 OLI Simulation Conference 2014
Aspen Simulation Workbook
D Kolesar October 2014 OLI Simulation Conference 2014
Input Table
D Kolesar October 2014 OLI Simulation Conference 2014
Input Table
D Kolesar October 2014 OLI Simulation Conference 2014
How Do You Prevent Pairs With No Chemistry?
D Kolesar October 2014 OLI Simulation Conference 2014
How Do You Prevent Pairs With No Chemistry?
---Conditional Drop Downs---
D Kolesar October 2014 OLI Simulation Conference 2014
How Do You Prevent Pairs With No Chemistry?
---Conditional Drop Downs---
D Kolesar October 2014 OLI Simulation Conference 2014
Tabular Output
D Kolesar October 2014 OLI Simulation Conference 2014
ASW Graphic Output
D Kolesar October 2014 OLI Simulation Conference 2014
ASW Graphic Output
D Kolesar October 2014 OLI Simulation Conference 2014
Works Great But…
The Aspen Dynamic Simulation in ASW Ran Well But...
When Change Starting Conditions in the Tank (i.e.
Temperature, Pressure, Composition), The Simulation
Would Not Initialize or Became Infeasible.
Stable in Aspen Plus But Not Aspen Dynamics with OLI
Properties.
Next Plan: Run Simulation In Aspen Plus With A
Sensitivity Clock
D Kolesar October 2014 OLI Simulation Conference 2014
What Is A Sensitivity Clock?
Means To Emulate Dynamic Behavior Using Aspen Plus
Steady State Simulator using a Sensitivity Block
Uses: − Sensitivity Block
− Transfer Block
− Sequence Block
D Kolesar October 2014 OLI Simulation Conference 2014
How Does The Sensitivity Block Clock Work?
In The Sensitivity Block, A Dummy Variable Is Created and
Incremented to Model Time.
Each Pass of the Sensitivity Block Represents a Time Step.
The Value of the Time Step Is Either Determined By the
Intrinsic Residence Time or Characteristics of the System or
User Determined if Less Restrictive Than System
Requirement.
As with Any Sensitivity Block, You Need to Store the Data
You Want to Keep From Each Run.
D Kolesar October 2014 OLI Simulation Conference 2014
Transfer Blocks
At the End of Each Pass of the Sensitivity Block,
Selected Output from the Simulation Is Transferred To
the Input Via Transfer Blocks.
With the Output now the Input, the Simulation Is Ready
to Begin The Next Time Step.
D Kolesar October 2014 OLI Simulation Conference 2014
Aspen Plus Flowsheet With Sensitivity Clock
1. Initial Tank Volume
(First Pass)
2. Truck Unloading
4. Relief Capacity
Calculations
6. Tank Contents
At End Of Time Step
3. Pressure if No Venting
Transfer Blocks
5. Tank w Actual Relief
D Kolesar October 2014 OLI Simulation Conference 2014
Results of Acrylic Acid Into A Potassium Hydroxide Tank
D Kolesar October 2014 OLI Simulation Conference 2014
Results of An Amine Pumped Into A Methacrylic Acid Tank
S-1 - Results Summary
VARY 1 PARAM 10
Y4
Axis
lab
el
PSI
A
F
LB/H
R
1 51 101 151 201 251 301 351 401 451 501 551 601 651 701 751 801 851 901 9510.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
14.59
14.60
14.61
14.62
14.63
14.64
14.65
14.66
14.67
14.68
14.69
14.70
14.71
14.72
14.73
14.74
14.75
14.76
14.77
14.78
14.79
14.80
14.81
14.82
14.83
14.84
14.85
14.86
14.87
14.88
14.89
14.90
14.91
14.92
14.93
14.94
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
200
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
200000
220000
TANKM
TANKT
RDFLOW
RVFLOW
VRVFLOW
GOOSEFLO
PTANK
TOTTOATM
D Kolesar October 2014 OLI Simulation Conference 2014
Acknowledgement / Recognition
Dow Colleagues:
− Dung Thi Vu
− Zak Kivitz
OLI:
− AJ Gerbino
− Pat McKenzie
− Jim Berthold
− Jerzy J. Kosinski
D Kolesar October 2014 OLI Simulation Conference 2014
Thank You Questions?
D Kolesar October 2014 OLI Simulation Conference 2014
