Transcript
Title Getting Started with
PROVISION and PRO/II
2
Course Content
• Introduction
• Guided and Independent Exercises
• Simulation in Seven Steps
• Main Parts of a Simulation
– Components
– Thermodynamics
– Streams
– Phase Equilibrium Calculations
– Unit Operations
– Columns
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A Brief History of Simsci-Esscor
• Simsci founded in Nov. 1966 by Dr. Wang
– SP03 - distillation program
• 1974: SSI/100 - first flowsheet simulator
• 1979: PROCESS - keyword, batch mode
• 1988: PRO/II - interactive
• 1995: PRO/II with PROVISION
– true 32-bit Windows-based application
• 1997: Simsci became a public company
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• 1998: Simsci acquired by Siebe
• 1999: Siebe merged w/ BTR and renamed the company - Invensys
• 2002: Simsci & Esscor merge
• Today
– $5 Billion company located in UK
– Diversified Engineering and Electronics group
– Employs more than 30,000 people worldwide
A Brief History of Simsci-Esscor
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PIPEPHASE
NETOPT
TACITE
Oil and Gas
Production
Simsci Solution Suites
PRO/II
HEXTRAN
VISUAL FLOW SUITE
INPLANT
DATACON
Process
Engineering
ROMeo
CONNOISSEUR
ARPM
On-Line
Performance
DYNSIM
FSIM
TRISIM
OTS
Dynamic
Simulation
Products fall into one of five
“Solution Suites”
COMOS FEED
iFEED
Introduction
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PRO/II vs PROVISION
• PRO/II is the Calculation Engine
– Solves Equations
• PROVISION Makes PRO/II Easy to Use
– Graphical User Interface
• PRO/II 5.0+: Microsoft Windows 95 or NT
• PRO/II 5.1.1+: Microsoft Windows 2000
• PRO/II 5.6+: Microsoft Windows XP
• SIM4ME will be very similar to PROVISION
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PRO/II Capabilities & Features
• Large component data bank and thermodynamics data bank
• Flexible and powerful refinery capabilities
• Reactive and electrolyte distillation modeling
• Regression and data management tools
• Advanced flowsheet sequencing capabilities
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PRO/II Capabilities & Features
• PROVISION (GUI)
– 32-bit Windows-based application
– Interactive execution
– Graphs, tables and charts can be exported
– OLE functionality
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Steady State Simulator
• No Time Dependent Phenomena
• Exception: Depressuring Unit
• Controllers & Instrumentation Are Irrelevant
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Remove Control Valves and Instrumentation
TI TI PI PI
LC LC LC
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Sequential-Modular Simulator
• Units solved one at a time
• Feeds must be known
• Recycles automatically handled
1
2 3
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Desktop Environment
• Menu bar
• Toolbar
– Can easily access many of the menu functions
• Color Cues
– Indicates required data entry
• Palettes
– PFD
– Run
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Desktop Environment
How to Do a Simulation in PRO/II
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Simulation in Seven Steps
1
Build Flowsheet
Check Units of Measure
2
Define Components
3
Select Thermo
4
Supply Stream
Data
5
Provide Process
Conditions
6
Run & View
Results
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Group Units if Desired
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• Common Source of Errors
• English is Default
• Default Can be Changed Globally (all Future
Simulations)
• Can be Changed for Entire Flowsheet
• Can be Changed Locally
• Can Define Custom Set of UOM
Units of Measure
Components
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Component Selection
• Pure component from a library
• User-defined component
• Petroleum component
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Petroleum Components
• Normal Boiling Point
• Gravity
• Molecular Weight
At least two of three required
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Simulate a Chiller Plant in 4 Parts
• Recover liquids & deliver gas to pipeline
C2
Pipeline Gas
T1 Stabilizer
M2
M1 Natural Gas
Liquids (NGL)
S14
S18 S20
S1
S19
V1
HX3
F3
Refrigerant
S12
S10 S11
S13
S17
F1
Cooling Air
S9
C1
HX1
F2 S2 S4 S5
S6
S7
S3
Inlet Gas
S8
HX2
S16
S15
S1
Selecting the Thermodynamics
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K-Value Calculation Methods
• Ideal
• Equation of State
• Liquid Activity
• Generalized Correlations
• Special Packages
• Electrolytes
• Polymers
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Selecting the Thermo Method
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• Refining Processes:
– Grayson-Streed: Hydrogen rich systems, Crude tower, Vacuum unit, Coker fractionator, FCC main fractionator
– SRK and PR: Light ends columns, Splitters, Gas recovery plants, Hydrogen rich systems (SRKM)
– SOUR, GPSWATER: Sour water systems
– SRKK, SRKM, SRKS, IGS: Use if H/C solubility in liquid water (VLLE) is important.
Hydrocarbon Systems
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Hydrocarbon Systems
• Gas Processing:
– SRK and PR: All types of processing plants, cryogenic systems
– SRKM, PRM, and SRKS: Systems with water, methanol, and other polar components
– GLYCOL: Dehydration with TEG. Improved for aromatic emissions. Based on SRKM.
– AMINE: Natural gas sweetening.
– SRKK, IGS, SRKM, SRKS: Use if light gas solubility in water (VLLE) is important.
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• Non-ideal components
• Low to medium pressures
• Rely on binary interaction parameters (if missing will be close to Ideal!)
• Missing parameters estimated from structures, azeotrope composition, mutual solubilities etc.
• Used with Henry’s Law for non-condensibles
• VLLE with some methods
Chemical Systems:
Activity Coefficient Methods
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Chemical Systems:
Activity Coefficient Methods
Two Binary parameters Liquids? in databank?
NRTL Yes Yes
UNIQUAC Yes Yes
WILSON No No
UNIFAC Yes Estimates non-ideality from structure
• Other methods - see Reference Manual
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Chemical Systems: Equations of State
• SRK-SIMSCI, SRKM, and PRM for polar mixtures
• SRK-Hexamer for mixtures involving HF
• Can model high-pressures
• Also relies on binary interaction parameters
• Some binary parameters in databanks for above methods
Supplying Stream Data
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Types of Streams
Internal Feed
External Feed
Product
Recycle
Product
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Stream Attributes
• Thermal Condition
• Flowrate
• Composition
– Defined by components
– Defined by assay data
– Referenced to another defined stream
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Stream Data
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Thermal Condition Data
• Pressure
• Temperature
• Liquid Fraction or Phase
– Saturated liquid at bubble point
– Saturated vapor at dew point
Specify two of these three properties
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• Satisfies a flowsheet specification by
manipulating an upstream parameter
• “Long-Distance” specifications and
variables
• Analogous to a process feedback
controller
Feedback Controller
Exercise: Chiller Plant - Part 3, p. 17
Add a controller
Distillation
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Tray Numbering
• Normally use Theoretical Trays (Stages)
• Numbered from Top Down
• Condenser is Stage 1
– Even for subcooled condenser
• Reboiler is Last Stage
– Thermosiphon adds 2 stages
• Convert Packing to Stage:
– Rule of Thumb: 2-3 feet of packing per stage
– Modern structured packing could be inches, so check with
the manufacturer
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Tray Efficiency
• Murphree yi,n = yi,n+1 + EiM
(yi,n*-yi,n+1)
• Vaporization yi = EiV Kixi
• Equilibrium Like EiV, but K’s - 1
• Vapor Leaving Stage not at Dew Point
• Can Lead to Mixed Phase Condenser Product
• Better to Use Overall Efficiencies
– Theoretical / Actual trays to carry out separation
– Use different values in different column zones
– Don’t forget condenser and reboiler!
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Tray Efficiency
xA
75% efficient:
step 3/4 to
equilibrium curve
yA
xA
l
l
100%
efficient:
step to
equilibrium
curve
• Murphree: yi,n = yi,n+1 + EiM
(yi,n*-yi,n+1)
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Typical Overall Efficiencies (%)
• Deethanizers: 60-65
• C3 Splitters: 95-100
• Crude Units:
– Stripping Section 30
– Flash Zone to Gas Oil 30-40
– G.O. Draw to Diesel Draw 40-50
– Diesel Draw to Kero Draw 45-55
– Top Section of Column 55-65
• Columns with reboilers and condensers: 60-80
• Pumparounds eliminate trays: 20-25
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Condenser Options
• Available in all algorithms
• Partial
• Vapor overhead product
• If present, Liquid product is side draw from stage 1.
• In Keywords, two product condenser is called “Mixed”
Overhead
Overhead
Side-draw
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Condenser Options (continued)
• Bubble
• Liquid product at bubble point
• Fixed temperature
• Sub-cooled at a specified temperature
• Delta T below bubble point
• Specify degree of subcooling
Overhead
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N-1
Bottom Tray
N
Reboiler BTMS Q
VN-1 LN-2
VN LN-1
BTMS
LN-1
VN
Kettle Reboilers
Vapor in Equilibrium with Bottoms
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BTMS
LN-1
VN
Bottom Sump Reboiler
Sump
Baffle
LN-1
VN
BTMS
Bottom
Sump
Single Pass (Once Through) Thermosiphon
• Equivalent to a Kettle Reboiler Because Bottoms is in Equilibrium with VN
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N-2
Bottom Tray
N-1
Combined Sump
N
Reboiler
BTMS
Q
VN-1 LN-2
RL RF
R V
LN-2
VN-1
R V
RL
RF BTMS
Combined Sump
Circulating Thermosiphon Adds 2 Stages
• Simulate as TS without Baffles
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BTMS
VN-1
Bottom Sump
RF
RV
RL
LN-2
Reboiler Sump
N-2
Bottom Tray
N-1
Reboiler Sump
N
Reboiler
BTMS
Q
VN-1 LN-2
RL RF
R V
Circulating Thermosiphon
Simulate as TS without baffle
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BTMS R L
R F
L o
R V
N-2 Bottom Tray
N-1 Reboiler Sump
N Reboiler
Bottom Sump
Q
V N-1 L N-2
BTMS
L N-2
V N-1
Bottom Sump Reboiler
Sump
R F
R V
R L
L O
Preferential Thermosiphon
Simulate as TS with baffle
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All Column Algorithms are Iterative
• Want to Solve f(x) = 0
• Generate a Sequence of Estimates of Solution:
x0, x1, x2, ... xN
• When all Equations are satisfied, i.e.
| f(xN) | < 0.001
• xN is Regarded as the Solution
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Convergence of Newton’s Method...
x xf
xf xn n
x
n
n
1
1
( )
Solution
f(X)
0
X x1 x2 x*
Good initial guess
leads to solution
x0
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Convergence is not guaranteed!
f(x)
x* X
0
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f(x)
x* X
0
Periodic
Convergence is not guaranteed!
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Bad guess
converges
But better
guess fails!
f(x)
x* X
0
Convergence is not guaranteed!
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You Can Help I/O by Using DAMPING
• DAMPING Reduces Iteration Step and Suppresses
Oscillation
• Conventional Columns: DAMP = 1.0 (default)
• Columns with Steam: DAMP = 0.6 -- 0.8
– Crude, Vacuum, FCC Main Fractionator
• Highly Non-ideal: DAMP = 0.4 -- 0.6
– If Oscillation Persists, Use Chemdist
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Distillation Algorithm Selection
• Generality.
• Total Pumparounds.
• VLWE on any Tray.
• Water draw from any tray
• Slow
• Sensitive to initial guesses
• Columns with free water or water draw on trays other than condenser.
• Total pumparounds or vapor bypass
Inside/Out (I/O) CHEMDIST
• Very fast
• Insensitivity to initial estimates.
• Thermo non-ideality.
• NO VLLE capability. (VLWE at condenser)
• Hydrocarbon Systems
• EOS & Slightly non-ideal LACT Thermo.
• Interlinked columns
• Side & main columns solved simultaneously.
• Reactive Distillation.
• VLLE on any tray.
• Highly Non-Ideal Systems.
• No Pumparounds.
• Side columns solved as recycles.
• Non-Ideal Systems.
• Mechanically simple columns
• VLLE within column
Unique
Features
Strengths
Limitations
Applicability
SURE
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• Inside Out (I/O)
– Relatively Ideal Thermodynamics Including Hydrocarbon with Water Decant (Enhanced I/O can handle water on the trays)
– Incorporates Sidestrippers into column -- No recycle!
– Thermosiphon Reboilers
– Very Forgiving of Bad Initial Estimates
– Fast!
– No VLLE
Distillation Algorithm Selection
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• Chemdist
– Mechanically simple columns, complex
thermo
– True VLLE
– Azeotropic and Reactive distillation
– Sidestrippers solved by recycle
– No Pumparounds or Thermosiphons
– More sensitive to Bad Initial Estimates
Distillation Algorithm Selection
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• Sure
– Very General: Complex Column and Thermo
– Use when I/O and Chemdist do not apply
– Newton Method
– Very sensitive to Bad Initial Estimates
– Side columns are solved as recycles
– Allows free water or water draw on trays other than
condenser
Distillation Algorithm Selection
Exercise: Chiller Plant - Part 4, p. 21
Add a column and compressor
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Output Options
• Export via Windows Clipboard
– Data in Spreadsheets
– Graphics
• Plots
• Output Files
• Stream Property Tables
• Unit Operation Tables
• Case Studies
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Thank you for attending
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