AL-NAHRAIN UNIVERSITY
COLLAGE OF ENGINEERNG
CHAMICAL ENGINEERING DEPARTEMENT
CHEMCAD
GIBBS REACTOR SIMULATION IN CHEMCAD
By
HUSSEIN HAMEED JASIM
GIBBS REACTOR
Gibbs Computes the equilibrium mixture composition given the reactor feed
composition and reactor operating conditions (e.g., T and P). All chemical species
contained in the component list may participate in the reaction unless specified as inert.
Equilibrium is determined by minimizing the total Gibbs energy of the mixture.
Thermodynamic data are provided in ChemCAD. Kinetic.[ CITATION che \l 1033 ]
For example.
Consider hydrogen/ nitrogen feed stream with the following properties:
Temperature 500 K
Pressure 100 atm
Compositio
20 mole % N 2 , 80 mole % H 2
n
Flow rate 1000 Kgmol/hr
To carry out ammonia production by Haber process.
The reactor specifications are as the following:
Reactor state Adiabatic
Pressure 100 atm
Pressure drop 10 atm
Molar convertion of N 2 0.5
Gibbs reactor design procedure solution [ CITATION che \l 1033 ]:
1. Start the ChemCAD application; choose menu item File > New and save as a File
on your computer's desktop.
2. In the Palette box, click on Reactors tab, then click on Gibbs reactor. Once the
reactor is selected, click on a point in the work space where you want the reactor
placed. Right clicking will unselect the reactor.
3. Then place, by selecting from the main palette, the Feed arrow and Product arrow.
Place the arrows accordingly near the reactor.
4. Next use the stream button (second row, and first column of the main palette) to
connect the input arrow to the top of the reactor, and the bottom of the reactor to
the output arrow; blue dots represent equipment feed streams and red dots
represent equipment outlet streams.
5. Select Thermophysical -> Component List and add nitrogen (46), hydrogen (1)
and ammonia (63). Click OK until you are through all the menus that come up.
6. Choose menu item Format -> Engineering Units to select SI units for this
problem; component flows should be mole fractions. Also, change pressure to
atmospheres. After making these choices, click OK.
7. Double-click on the square input stream box to specify input stream properties.
Enter the feed properties listed above.
8. Next, double-click on the Gibbs reactor. Specify the thermal mode to adiabatic.
Set the reaction phase to [1 Vapor or mixed phase] and press OK and OK at the
Component Element Matrix.
9. From the main menu, select Run -> Run All; correct errors, if any.
10.From the solution report obtained from Report click on the Calculate and Give
Results button.
Simulation: Hussein Hameed Jasim (final Date: 07/11/2020 Time: 01:59:16
STREAM PROPERTIES
Stream No. 1 2
Name feed product
- - Overall - -
Molar flow kmol/h 1000.0000 869.9001
Mass flow kg/h 7215.4399 7215.4800
Temp K 500.0000 734.3672
Pres atm 100.0000 100.0000
Vapor mole fraction 1.000 1.000
Enth MJ/h 5998.1 5998.3
Tc K 56.8888 109.4148
Pc atm 25.1218 40.2017
Std. sp gr. wtr = 1 0.241 0.281
Std. sp gr. air = 1 0.249 0.286
Degree API 456.2533 372.0284
Average mol wt 7.2154 8.2946
Actual dens kg/m3 16.8737 13.3656
Actual vol m3/h 427.6140 539.8542
Std liq m3/h 29.9711 25.6764
Std vap 0 C m3/h 22413.6465 19497.6328
- - Vapor only - -
Molar flow kmol/h 1000.0000 869.9001
Mass flow kg/h 7215.4399 7215.4800
Average mol wt 7.2154 8.2946
Actual dens kg/m3 16.8737 13.3656
Actual vol m3/h 427.6140 539.8542
Std liq m3/h 29.9711 25.6764
Std vap 0 C m3/h 22413.6465 19497.6328
Cp kJ/kg-K 4.1155 3.9744
Z factor 1.0424 1.0300
Visc N-s/m2 2.126e-005 2.729e-005
Th cond W/m-K 0.1856 0.2255
- - Liquid only - -
Molar flow kmol/h
Mass flow kg/h
Average mol wt
Actual dens kg/m3
Actual vol m3/h
Std liq m3/h
Std vap 0 C m3/h
Cp kJ/kg-K
Z factor
Visc N-s/m2
References
[1] A. m. ©. 2. C. I. chemcad, "CHEMCAD Version 6 User Guide".
[2] M. Hamad, chemcad lictures.
