1. Gas Processing Center, College of Engineering, Qatar University, Doha P.O. Box 2713, Qatar
2. Department of Chemical Engineering, College of Engineering, Qatar University, Doha P.O. Box 2713, Qatar
3. Department of Chemistry and Earth Sciences, College of Arts and Science, Qatar University, Doha P.O. Box 2713, Qatar
4. Department of Geosciences and Geological and Petroleum Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA