Hysys simulation

HYSYS SIMULATION
Zin-Eddine Dadach
2010-2011

Objective of the course
 The purpose of this course is to introduce the
use of HYSYS as a modeling and analysis tool in
the Unit Operations Laboratory of the chemical
engineering program.
 HYSYS can help the students perform lengthy
calculations in a manner of a few seconds.
Hence, students can make parametric analysis
and other evaluations with ease and can provide
a more in depth analysis of the performance of
unit operations in the laboratory.

WHAT IS HYSYS ?
 HYSYS is powerful software for simulation of
chemical plants and oil refineries.
 HYSYS can:
 Estimate physical properties and liquid-vapor
phase equilibrium.
 Simulate many types of equipments including
pumps, compressors, tanks, columns and reactors
 Perform Material and Energy balances.
 Equipments design
 Cost estimation

HYSYS and Thermodynamics
 The most important factor in the simulation of
chemical processes is certainly the physical properties,
particularly phase equilibrium required for modeling
distillation, stripping, absorption and extraction.
 1) Basis:
a) First we enter all the components present in the
plant
b) we then have to select a fluid package or an Equation
of state from HYSYS
2) Simulation:
We enter the conditions and compositions to define
the system.

HYSYS :System
 In HYSYS, students should first define the system ( Like
in Thermodynamics course)
 HYSYS will help the students:
 Define the composition of the system ( select
components from the data base)
 Introduce known properties of the system ( Pressure,
temperature, flow, % vapor,…) until the system is
completely defined. ( Light bleu  Dark bleu)
 For example: the enthalpy of a system will be calculated
by HYSYS if the temperature and pressure are known.
 Alternatively, a student will be able to predict the
temperature of a system if the enthalpy and pressure
are known.

Basics Of Steady-State
Process Simulation
 HYSYS is one the most popular Process
Simulator with ASPEN PLUS, CHEMCAD and
PRO/II
 In this course, we will study only The steady
state Simulation. ( No dynamic simulation)
 It is used to determine the temperatures,
pressures and compositions and total flow
at steady state
 They also perform material and energy
balances.
 They simulate the sizes and costs of
process units.

Process Flowsheets
 Process Flowsheet ( Figure 4.1 page
109)
- Collection of icons to represent process
units
- Arcs to represent the flow of materials to
and from units
- Emphasizes the flow of materials and
energy in a chemical process

PROCESS  SIMULATION
 To convert from a process flowsheet to a
simulation flowsheet, we should replace the
process units with the appropriate simulation
units
 For each simulation unit, a subroutine ( block
or model) is assigned to solve its equations
 Each simulator has an extensive list of
subroutines to model or solve the process unit
equations.
 Partial List of these subroutines are
represented in Table 4.1 pages 114-115

Simulation Flowsheets
 Simulation Flowsheet:
( Figure 4.2c page 111)
- Collection of simulation units to represent
computer programs ( Subroutines or
models) that simulate the process units
and arcs to flow of information among the
simulation units

Simulation Flowsheet
 The arcs in simulation flowsheet represent
the transfer of flow rates, temperature,
pressure, enthalpy, entropy, and vapor
and liquid fractions for each stream
 The stream names can be thought of as
the names of vectors that store stream
variables in a specific order ( example for
ASPEN page 112)

HYSYS SIMULATION
 The icons in Figure 4.2c represent
simulation units For HYSYS
 In Figure 4.2c, for HYSYS.Plant, the unit
names are in upper case and the model
names are tabulated separately in
boldface ( Page 111)

INTRODUCTION
 Before any simulation can occur, HYSYS
needs to undergo an initial setup.
 During an initial setup or BASIS, you
should introduce:
 The components that will be used
 The fluids package will be selected.

Starting a NEW CASE
 Starting a New Case in HYSYS
 Start HYSYS, and click on the “New Case”
button to open up the “Simulation Basis
Manager” which is where all of the
components and their properties can be
specified.

Add Components
 To add components to the simulation, click on the “Add” button in
the Simulation Basis Manager.
 Clicking on “Add” will bring up the “Component List View” which is a
list of all the components available in HYSYS.
 Type in the name of the desired component in the Match window
and click on “Add Pure” to add it to the simulation.
 Close the Component List View when all of the components are
selected.
 Note: The Full Name/Synonym option makes finding components
the easiest. To enter components by HYSYS’s simulation names, or
by chemical composition, select “Sim Name” or “Formula”
respectively.

Selecting Fluid Package
 In the Simulation Basis Manager, click on
the “Add” button to specify a fluids
package.
 Doing so will bring you to a list off all the
different equations of state HYSYS uses.
 Pick the appropriate fluid package for the
system you wish to study.
 To select the appropriate package,
double click on the text that is displayed.

BASIS OF THE SIMULATION
 The fluid package and the list components are
the BASIS of your simulation.
 When the basis of the simulation has to be
changed, the Simulation Basis Manager needs
to be re-entered. Simply click on the icon
on the top toolbar to re-enter it.
 If, during the simulation, you forget a
component or have a wrong one or you have
the wrong fluid package, you need to go back
to BASIS and make the corrections.

Working in the PFD
Entering Simulation:
 Once the components, fluids package and applicable
reactions are selected, the Simulation is ready to be run.
Click on “Enter Simulation Environment” in the
Simulation Basis Manager window.

Accidentally Closing the PFD
 Sometimes, you accidentally click the X on
the PFD.
 To get it back, simply go to “Tools” –>
“PFDs”
 Make sure “Case” is selected,
 Then click “View”

Material & Energy Streams
 Placing Material Stream
 Material Streams are used to transport the
material components from process units in
the simulation.
 To place a material stream, click the Blue
arrow on the simulation toolbar and then
click somewhere on the turquoise
simulation window.

Placing ENERGY Stream
 Energy streams are used to specify how
much energy a process unit such as a
pump or compressor needs.
 To place an energy stream, click on the
red arrow on the simulation toolbar, and
then place it on the simulation window.

RENAMING STREAMS
 In order to make the simulation easy to
follow, the streams need to be renamed.
 Double click on the arrow to bring up the
properties window for stream 1.
 To rename it, click on the tab next to
“Stream Name” and simply type in the
appropriate name for it.

SELECTING PROCESS UNITS
 To place process units, simply select them
from the Simulation Toolbar, and place
them on the PFD.
 Note: If the cursor hovers over an item
on the toolbar, a text box appears; telling
which item is going to be selected.

EXAMPLE: SELECTING A
DISTILLATION COLUMN

Accidentally Closing the
Simulation Tool bar
 Sometimes, people will accidentally click
the small X on the Simulation Toolbar. To
get it back click on the button to bring it
back.

DEFINE YOUR SYSTEM
In all chemical processes, a number of properties
or degrees of freedom must be specified.
 To specify properties a stream, double click on
it to open up the specification menu. Select
the appropriate column and simply type in the
values of the specification.
 Note: HYSYS allows you to enter in any unit
you wish. To specify the unit of the number
that is being entered in, simply click on the
arrow next to the unit to bring down a menu.
Simply select the desired unit to input

SELECTING PROPERTIES LIKE
TEMPERATURE, PRESSURE AND
MOLAR FLOW

SYSTEM COMPLETELY DEFINED
 When you selected enough variables to define
your system:
 You see GREEN LIGHT IN THE PFD
 HYSYS calculates for you the other variables.
 The values in BLUE are your selected
parameters and can be changed.
 The values in BLACK are the values
calculated by HYSYS and can not be
changed.

System defined and Green light

Workbook
 To get a more in-depth, printable view the
stream properties, HYSYS can create a
workbook.
 To create a workbook, clicking “Tools” –>
“Workbooks” will bring up the workbook
selector.
 Double click on “Case” to bring up a
summary of all the properties on the
process and energy streams.

Add properties in Workbook
 To add additional properties not displayed by
default, click on “Workbook” –> “Setup” in the
main tool bar.
 Once there, click on “Add” under the Variables
section and scroll down until the desired
property is located.
 Close the Setup window and the workbook is
now updated with the desired properties.
 Note: The “Workbook” option in the main
tool bar will only be present if the workbook is
open

Printing
 To print the workbook, leave it open and
go to File –> Print in the main toolbar.
 If the entire workbook doesn’t need to be
printed, click on the “+” and deselect the
undesired sections,
 Then click Print.

Class work #1
 A feed ( 20 lbmoles/hr) of a mixture
propane and n-butane containing
70% ( mass) propane at 20 atm,
using the Peng Robinson, find:
 the dew point
 the temperature when the vapor
fraction is 0.7

Class work #2
 A feed ( 10 lbmoles/hr) of an
equimolar mixture of n-pentane and
n-hexane is at 10 atm , Using the
Peng Robinson, find:
 the bubble point
 the temperature when the liquid
fraction is 0.7

Class work #3
 A feed containing 50 lb/hr of n-
pentane and 140 lb/hr of n-hexane is
at 160 psia, using the Peng-
Robinson, find the temperature to
have :
 a) 30% liquid
 b) at dew point

Flash-Separation
VAPOR-LIQUID EQUILIBRIUM

Flash separator from CD
 This session is meant to introduce you to
the use of Hysys for Steady state
simulation.
 Thermodynamics ( K values) and
introduction to separation from CD

FLASH CALCULATION
BY UNISIM
 An important feature of flowsheet
simulators is the ability to determine
automatically the equilibrium phase
distribution among vapor, liquid, and/or
solids for each stream in the process by
performing a flash calculation, which
makes use of the equilibrium coefficients
( K values)

K VALUES
 For example, vapor-liquid equilibrium
coefficient are defined by Kj= yj/xj
yj = mole fraction of species j in the vapor phase
xj = corresponding mole fraction in the liquid
phase at equilibrium

EXAMPLE
ACETONE + WATER MIXTURE

Initial Step
 Insert water and acetone in the
component list
 Choose the Antoine Package as the fluid
package

ENTER SIMULATION
 Click on Enter Simulation Environment
Button.
 This will put you in the PFD ( Process Flow
Diagram) mode.
 You can create a flow-sheet on this
screen.
 You will also see a menu-bar of available
unit operations on the right. ( Called the
Object Pallette).

SIMULATION
 Click on the Separator icon from this tool
bar and then bring your cursor to the PFD
area and click once to place this unit on
the flow-diagram.

OPEN THE SEPARATOR
 double click on this new block ( V-100) to
open this object. This object has the
following tabs:
Design/Reactions/Rating/Worksheet/Dyna
mics.
 Under Design, we have the menu choices:
Connections ( currently active as shown
above)/Parameters/User Variables/Notes.

Adiabatic/ Isothermal flash
 In adiabatic flash  No heat exchange
with the surroundings. Put the name of
the duty and the value zero (0) in the duty
of the separator
 In isothermal flash  Put a name for
separator duty and put the outlet
temperature equal to inlet temperature.

Example of adiabatic flash
 Enter the pressure drop as 10 psia and the
Heat Duty as 0. This creates an Adiabatic
Flash.

FEED CONDITIONS
 On the Worksheet tab and enter the feed
stream conditions.

Case study on CD
FLASH CALCULATION

Class work #4
 FLASH CALCULATION:
A feed of equimolar mixture of nC5 and
nC6 is at 1300F and 73.5 psia with a feed
of 1lbmole/hr.
The feed is flashed at 1200F and 13.23 psia.
Calculate the composition of the vapor and
liquid phase from the flash column

Class work #5
 A Saturated vapor at 250 psia and 10,000 lb/hr contains
80% NH3 and 20% H2O.
 The feed is cooled in a condenser where 5.8 106 BTU/hr
is removed from the feed and the pressure drop in the
cooler is zero.
 The feed then is flashed through a valve and a flash
drum where the pressure drop in the valve is 150 psia
 Calculate the composition of the liquid and gas phase of
the flash drum

From CD
 Overview
 Theory

Adiabatic heat exchanger
 For an adiabatic heat exchanger (no heat
transferred with environment), there are
three equations for the duty Q, i.e. the
rate of heat exchange between the two
process streams:
 Q = Nps (Hps,in –Hps.out ) (1)
 Q = Nus (Hus.out –Hus,in ) (2)
 Q = U.A.F.Tavg (3)

 Q is the rate of heat exchange (e.g., in kJ/h)
 N is the flow-rate of stream (e.g, in kmol/h)
 H is the specific enthalpy of stream (kJ/kmol)
 U is the overall heat transfer coefficient
(kJ/m2.K)
 A is the heat exchange area (m2)
 F is the correction factor for the deviation from
co-current or countercurrent flow
 See, for example, Figure 11-4 in Perry's)

NEED only the duty Q
 CHOOSE HEATER OR COOLER
 Define the conditions of the stream before
and after the heat exchanger and the duty
Q is calculated by HYSYS.

Energy balance around the heat
exchanger
 SHELL AND TUBES HEAT
EXCHANGER MODEL

HEAT EXCHANGER DESIGN:
END POINT MODEL
 "The End Point model treats the heat curves for
both Heat Exchanger sides as linear.
 For simple problems where there is no phase
change and Cp is relatively constant
 The main assumptions of the model are:
• Overall heat transfer coefficient, U is constant
• Specific heats of both shell and tube side
streams are constant

HEAT EXCHANGER DESIGN:
WEIGHTED MODEL
 The Weighted model is an excellent model to deal with
non-linear heat curve problems such as the phase
change of pure components in one or both Heat
Exchanger sides.
 With the Weighted model, the heating curves are broken
into intervals, and an energy balance is performed along
each interval. A LMTD and UA are calculated for each
interval in the heat curve, and summed to calculate the
overall exchanger UA.
 The Weighted model is available only for counter-current
exchangers, and is essentially an energy and material
balance model. The geometry configurations which
affect the Ft correction factor are not taken into
consideration in this model.

CD
 SHELL AND TUBES HEAT EXCHANGERS

CLASS WORK
 TUTORIALS FROM CD

DISTILLATION BY UNISIM
 Relative volatility :
jj
ii
xy
xy
/
/

),(
),(
),(
TPxx
TPyy
TP


 

 Necessary for defining a column:
Operating pressure of condenser
 Operating pressure of reboiler
 Reflux Ratio
 Number of trays
 Feed Tray

Shortcut theory for multicomponent
distillation
 I) Define light and heavy keys
 Example for DeC3 with feed components
ethane, propane, butane, pentane and
hexane
 The light key could be propane
 The heavy key could be butane
 WE have “binary-like” distillation

Fenske-Underwood-Gilliland
 To obtain initial estimates for multicomponent
distillation we use FUG equation
 Relative volatility: Difficulty involved to separate
2 components
 Nmin
j
i
jj
ii
ij
K
K
xy
xy

/
/

Bottom HK LK
Distillate HK LK N
x x
x x
) / (
) / ( min
 
BottomHKLK
DistillateHKLKN
xx
xx
)/(
)/(min


 It’s customary to use a geometric average of the
distillate and bottom streams
 This value of άis introduced in the previous equation
BHKLKDHKLKmean )(*)(  

UNERWOOD EQUATIONS TO
CALCULATE Rmin
LKHK
HKLK
Di
n
i HKLK
Fi
R
x
q
x












min
1 _
1
/1
1
/1

STEP 1 = CALCULATE θ
q
xn
i HKi
Fi


 
1
/11 

evapH
q



 q= thermal state of the feed
 Feed q
Supercooled 1<q
Liquid-vapor o<q<1
Superheated q<0
λ = Latent heat of evaporation
 Δ Hevap= Heat necessary to evaporate the feed

DETERMINE A VALUE FOR θ ONCE q
IS DETERMINED
q
xn
i HKi
Fi


 
1
/11 

evapH
1

STEP2 = CALCULATE RMIN
min
min
1
1
75.1
1
/1
1
/1
RR
R
x
q
x
LKHK
n
i HKi
Di
n
i HKi
Fi








 
 




ACTUAL NUMBER OF TRAYS
 For known Nmin and Rmin Use EDULJEE equation
:
})
1
(1{75.0
1
5688.0minmin





R
RR
N
NN

OPTIMAL FEED TRAY
 Kirkbride equation:
 Calculate x in the first equation and substitute
in the second equation to estimate NF
X
NX
N
x
x
x
x
D
DF
X
F
HKD
LKB
LKF
HKF




1
)}
)(
)(
.{
)(
)(
.( 206.02

REACTORS IN HYSYS
1) CONVERSION
2) EQUILIBRIUM
3) KINETIC

STARTING POINT
 ADD THE REACTION IN THE BASIS
BEFORE YOU ENTER SIMULATION
 Go to Basis and select “Reaction
Package”
 Select the reaction tab ( Conversion,
equilibrium, Kinetic,…) of the Simulation
Basis Manager and click on “Add
Reaction”.

Five different reactions
 There are currently five different types of
reaction that may be simulated in HYSYS
and a number of reactor types that they
may be used with (and one special reactor
that does not require any equations).
 The five reaction types are as follows:

Conversion Reaction
 This reaction type does not require any
thermodynamic knowledge. You must input the
stoichiometry and the percentage of
conversion of the basis reactant.
 The reaction will proceed until either the
specified conversion has been reached or a
limiting reagent has been exhausted.
 Conversion reactions cannot be used with Plug
Flow Reactors or CSTRs. In general, they should
only be used in Conversion Reactors.

Equilibrium Reactions
 Equilibrium reactions require that you
know some sort of relation between the
reaction's equilibrium constant, Keq,
and temperature. You may specify Keq
in a number of ways:

EQUILIBRIUM REACTIONS
1) As a constant. Enter either Keq or
Ln(Keq)
2) As a function of Temperature. You
specify A-D in the equation :
 Ln(Keq) = A + B/T + C*Ln(T) + D*T

Equilibrium Reactions
3) As tabular data of Keq vs. T
4) Have HYSYS determine Keq from the Ideal Gas
Gibbs Free Energy Coefficients. This is similar to,
but not exactly like what you get by attaching
any equilibrium reaction to a Gibbs Reactor
(which just takes the stoichiometry).
5) You may also search for the reaction among the
pre-defined reactions in the HYSYS library
(reached from the Library Page of the
Equilibrium Reaction window)

Kinetic Reactions
 All three of the remaining reaction types
can be considered kinetic, in that they
deal with an expression for the rate of the
reaction.

KINETIC REACTIONS
In this first and simplest form, the rate equation
is the one to the left
The first term on the right hand side refers to
the forward reaction, the second term to the
optional backward reaction.
The k's are the reaction constants for which you
must enter on the Parameters Page the
activation energies, E and E', and the pre-
exponential factors, A and A' (which are basically
all of the constants lumped out front).

EX: adding an Equilibrium reaction

Entering the reaction
1. When the Reaction window appears:
2. select the components which are present
during the reaction, and enter their
Stoichiometric Coefficient.
3. Keep in mind that the reactant must have a
negative coefficient and products must have
positive coefficient
4. Click “Balance” to check the guesses.
5. Notice status of the reaction goes from not
ready to ready. Close the window.


Click on Basis Tab
 Enter the specifications of the reaction:
 Example: for conversion reaction. Enter
the percentage of conversion

ADDING THE REACTION SET
 Click on “Add Set” and then add “Rxn –
1” to the Active List.

Final Step :ADDING TO FP
 Click “Add to FP”, make sure that fluid
package is selected and click “Add Set to
Fluid Package”.
 Now the simulation is setup.
 Click on “Enter Simulation Environment
to go to the PFD and start the
simulation.

Three kinds of reactors
Conversion Reactors
Equilibrium Reactors
Kinetic Reactors

WHEN TO USE IT?
 WHEN YOU HAVE A REACTION WITH
STOCHIOMETRY
 WHEN YOU HAVE A CONVERSION
 A CONVERSION REACTOR CANNOT BE A
PLUG FLOW OR A CSTR REACTOR
 THEY ARE CALLED CONVERSION
REACTORS

Example of case study
 A stream of pure methane at 400 bar and
87 °C and flowing at 32 kg/hr enters in a
reactor, where it undergoes combustion.
There is excess air in the reactor and the
conversion is 95%.

INITIAL STEP
Start a new case in HYSYS
 Select methane, oxygen, nitrogen, water,
and carbon dioxide as the components.
 Since these components are all gasses,
select the Peng-Robinson fluid package.
 Select the reaction tab of the Simulation
Reaction”.

CONVERSION REACTION
 Since this is a conversion reaction, select
it from the list.

stoichiometry
 Select all of the components that are
present for the combustion of methane,
and enter in guesses for their
stoichiometric coefficients, keeping in
mind that the reactants, methane and air,
must have negative coefficients. Then
click “Balance to correct the coefficient
guesses

Percentage of conversion
 Now the conversion needs to be
specified. Click the basis tab, and enter
in 95 under “Co”.
 Take note that the conversion has to be
in percentage form, not decimal form.
 The reaction now goes from “Not Ready”
to “Ready”.

NOTE
 You will see a conversion equation below
the component windows that looks like
Conversion (%) = Co + C1*T + C2*T^2;
 Here the conversion is just a straight 95%
conversion so only a Co is needed,
 However, if there was a 1st &/or 2nd
order temperature dependent conversion
values for C1 and C2 would need to be
added.

Click on “Add Set” and add “Rxn – 1”
to the Active List.

Add reaction to fluid package
 Click “Add to FP”, make sure that PP:
Peng-Robinsion is selected and click “Add
Set to Fluid Package”.

Connecting the reactor
 Double click on the Conversion Reactor
to bring up its connection menu.

CLASS WORK #1
 STYRENE IS MADE BY DEHYDROGENATION OF
ETHYL-BENZENE FOLLOWING THE REACTION:
C6H5-C2H5 C6H5=C2 H3 + H2
o THE FEED ( 217 GMOLES/S) AT 880K AND
1.378 BARS ENTERS THE REACTOR
o IF WE WANT TO CONVERT 80% OF ETHYL-
BENZENE, FIND THE FLOWRATES AND
COMPOSITION OF THE PRODUCTS

CLASS WORK #2:FROM CD
 2 moles of Hydrogen react with 1 mole
monoxide carbon to produce methanol
 We assume 70% conversion of monoxide
carbon in an ISOTHERMAL REACTOR
 The feed has a temperature 300C, a
molar flow 70 kgmole/hr and a pressure of
10000KPa

Class work #3
 Combustion of methane with air with
95% conversion of methane
 Methane enters the reactor at 400 bar,
87 °C, and has a flow rate of 37 kg/hr.
 Oxygen enters the reactor at 1 atm, 25
°C, and is in excess with the methane.

WHEN TO USE IT?
 WHEN YOU KNOW THE RELATIONSHIP BETWEEN THE
EQUILIBRIUM CONSTANT KEQ AND TEMPERATURE
 YOU MAY SPECIFY KEQ IN DIFFERENT WAYS:
 KEQ IS A CONSTANT: ENTER EITHER KEQ OR LN ( KEQ)
 AS A FUNCTION OF TEMPERATURE:
LN( KEQ)= A + B/T + C.LN (T) + D.T ( T IN KELVIN)
 A TABULAR DATA OF KEQ VS TEMERATURE ( HYSYS)
 HAVE HYSYS DETERMINE KEQ FROM THE IDEAL GAS GIBBS FREE
ENERGY COEFFICIENTS  YOU HAVE GIBBS REACTOR
 SEARCH IN HYSYS LIBRARY FOR PREDEFINED REACTIONS

EQUILIBRIUM REACTORS
 EQUILIBRIUM REACTOR CANNOT BE A
PLUG FLOW OR CSTR REACTOR
 THEY ARE CALED EQUILIBRIUM
REACTORS
 GIBBS REACTOR IS USED WHEN K IS
BASED ON THE IDEAL GAS FREE ENERGY
COEFFICIENTS,

EXAMPLE
 Equilibrium Reactors
 A 100 kg-mol/hr feed containing 50 mol%
Nitrogen and 50 mol% Hydrogen entering
at 1 atm and 50 C is to undergo an
equilibrium reaction to produce ammonia.

INITIAL STEP
 Select Nitrogen, Hydrogen, and
Ammonia as the components.
 Since these components are all gasses,
select the Peng-Robinson fluid package.
 Select the reaction tab of the Simulation
Reaction”.

Stoichiometry
 When the Equilibrium Reaction window
pops up, select the components which
are present during the reaction, and
enter in guesses for their Stoichiometric
Coefficient.
 Keep in mind that the reactants,
Nitrogen and Hydrogen, must have a
negative coefficient. Click “Balance” to
check the guesses.

Keq=Equilibrium Constant
 If Keq is a fixed number
 If the Equilibrium Constant Keq is known it
can be entered into HYSYS directly by
selecting the “Fixed Keq” option. Then
select the “Keq” tab. Once there enter in
the Keq constant directly in, and the
reaction is ready.

If a Ln(Keq) equation is known
 If a temperature dependant Ln(Keq)
equation is known, itcan be entered into
HYSYS as well. Select “Ln(Keq) and then
select the “Keq” tab. Once there enter in
the equation constants can be entered in
to the A, B, C… etc tabs as shown in the
equation to the right.

FROM HYSYS LIBRARY
 If the reaction is in HYSYS's Reaction Library
 HYSYS has tabulated equilibrium data for several
common equilibrium reactions.
 When setting up an equilibrium reaction, always check to
see if the reaction is in the reaction library, as it is the
most accurate method of solving.
 To use a reaction from the equilibrium library, select the
Keq vs. T table option, and then select the “Library” tab.
 Once there, scroll through the list of reactions and check
to see if it is there. If it is there, select it and press “Add
Library Reaction”

Adding reaction to active list

 GIBBS REACROR IS AN EQUILIBRIUM
REACTOR USING GIBBS FREE ENERGY

Class Work
 A feed containing 3 kgmol/hr Ethane and
1.5 kgmol/hr water entering at 1 atm and
3500C is to be cracked into Ethylene and
Hydrogen using a Gibbs reactor.

SOLUTION
 Initial Setup
 Start a new case in HYSYS
 Select Water, Ethylene/Ethene, Ethane, and
Hydrogen as the components.
 Since these components are gasses at high
temperatures, select the SRK fluid package.
 Select the reaction tab of the Simulation Basis
Manager and click on “Add Reaction”.

Feed Specifications
 Specify the feed stream. It is at 1 atm,
350 °C, has a ethene molar flow rate of
3 kg-mols/hr, and a water molar flow
rate of 1.5 kg-mols/hr.

Selecting reaction type
 Since Gibbs reactions are Equilibrium
reactions, select “Equilibrium” from the
menu

Adding stochiometry
1. When the Equilibrium Reaction window pops
up, select the components which are present
during the reaction, and enter in guesses for
their Stoichiometric Coefficient.
2. Keep in mind that the reactant, Ethane, must
have a negative coefficient. Click “Balance” to
check the guesses. Notice status of the
reaction goes from not ready to ready.
3. Close the window.

Add your reaction SET
 Click on “Add Set” and then add “Rxn –
1” to the Active List.

Add Set to Fluid Package
 Click “Add to FP”, make sure that PP:
SRK is selected and click “Add Set to
Fluid Package”.

Adding the Feed to PFD
 Place the feed ( material Stream)

Gibbs Reactor
 Double click on the Gibbs Reactor to
bring up its connection menu.
 Connect the Feed to inlet and add the
liquid and vapor streams to their
appropriate locations.

NOTE
 Check the Reactions tab, and as long as
“Gibbs Reactions Only” is selected, no
further specifications are necessary.

FEED SPECIFICATIONS
 Specify the feed stream. It is at 1 atm,
350 °C, has a ethane molar flow rate of 3
kg-mols/hr, and a water molar flow rate of
1.5 kg-mols/hr

Cracking reactions
 For cracking reactions, temperatures
around 1000 °C are needed.

Class work
 A feed containing 3 kg/mol-hr Ethane and
1.5 kg-mol/hr water enters a Gibb’s
reactor at 1 atm and 350ºC and is to be
cracked into ethylene and hydrogen (
WATER DOES NOT REACT).
 Use SRK equation of state
 The problem here is to determine the
reactor temperature for a desired
conversion.

KINETIC REACTORS
 PLUG FLOW
 CSTR
 LANGMUIR –HINSHELWOOD

Hysys simulation

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