Application of Gibbs Free Energy Minimization method using Spreadsheets to Predict Equilibrium Conversions in a Claus Reaction Furnace

Utkarsh Ujjwal*, Rahul Sikka**, Balaji Gulgule***, Tanmay Taraphdar****, M.K.E. Prasad*****
* Chemical Engineering Department, Thapar University, Patiala.
** Chemical Engineering, Birla Institute of Technology and Science, Pilani.
***-****-***** Technip KTI Ltd, Noida.
Periodicity:February - April'2012


This article presents a method to predict the equilibrium composition and temperature of a reaction mixture in gas phase as found in the reaction furnace of the Claus Sulphur Recovery Unit (SRU). The proposed method is useful for process design as well as plant performance optimization. An expression for the Gibbs free energy of the system in terms of temperature is derived by using the Soave-Redlich-Kwong (SRK) equation of state. Temperature correlations for Gibbs free energy of formation of various components in the reaction mixture are obtained using standard heat capacity (Cp) temperature correlations. Initial assumption for the furnace outlet temperature is made to calculate the value for the Gibbs free energy of the system. Solver function minimizes this value by varying the composition of the outlet stream using mathematical optimization methods for non-linear systems. The outlet stream composition corresponding to this value is the equilibrium composition as the Gibbs free energy of a system reaches minimum at equilibrium. Application of Gibbs free energy minimization method using the Solver feature present in the Microsoft Excel spreadsheet program is found to predict effectively the equilibrium composition and temperature of the outlet streams of reaction mixtures in three plant case studies of Claus Sulphur Recovery Unit.


Gibbs free energy minimization, Claus furnace, Solver

How to Cite this Article?

Ujjwal, U., Sikka, R., Gulgule, B., Taraphdar , T., and Prasad , M. K. E. (2012). Application Of Gibbs Free Energy Minimization Method Using Spreadsheets To Predict Equilibrium Conversions In A Claus Reaction Furnace. i-manager’s Journal on Future Engineering and Technology, 7(3), 48-57.


[1]. Y. Lwin. (2000). Chemical Equilibrium by Gibbs Energy Minimization on Spreadsheets, Int. J. Engg Ed. Vol.16, No 4, pp. 335-339.
[2]. Goar, B. G. (1986). Sulfur Recovery Technology, AIChE Spring National Meeting, New Orleans, Lousiana.
[3]. IS 1460. 2005 (5 Rev) (2010). Automotive Diesel Fuel Spevification.
[4] The Hindu, September 24, (2010). India switches fully to Euro III and Euro IV Petrol and Diesel.
[5]. B. ZareNehzad, and N. Hosseinpour, (2008). Evaluation of different alternatives for increasing the reaction furnace temperature of Claus SRU by chemical equilibrium calculations, Applied Thermal Engineering, 28, pp.738-744.
[6]. Perry, R.H., Green, D.W., & Maloney, J.O. (1997). th Perry's Chemical Engineering Handbook, 7 Edition.
[7].Rao, Y.V.C. (1997). Chemical Engineering st Thermodynamics, 1 Edition. Universities Press, A.1 Critical constants of some selected substances, PP.529-530, A.3 Isobaric molar heat capacities of some selected gases in the ideal gas state, PP. 532-533.
[8]. Smith, J.M., Van Ness, H.C., and Abbott, M.M. (1997). th Introduction to Chemical Engg. Thermodynamics, 5 Edition.
[9]. Chase, M. W. (1985). JANAF: Thermo chemical Tables for Standard Thermodynamic Properties of Chemical Substances. American Chemical Society for the Bureau of Standards, Washinton, D. C.
[10]. Reid, R.C., Prausnitz, J.M., & Sherwood, T.K. (1977). rd The Properties of Gases and Liquids (3 Edition).

Purchase Instant Access

Single Article

North Americas,UK,
Middle East,Europe
India Rest of world
Pdf 35 35 200 20
Online 35 35 200 15
Pdf & Online 35 35 400 25

If you have access to this article please login to view the article or kindly login to purchase the article
Options for accessing this content:
  • If you would like institutional access to this content, please recommend the title to your librarian.
    Library Recommendation Form
  • If you already have i-manager's user account: Login above and proceed to purchase the article.
  • New Users: Please register, then proceed to purchase the article.