EFFECT OF ZRO2 , WO3 ADDITIVES ON CATALYTIC PERFORMANCE OF PT/HY ZEOLITE COMPARED WITH PT/Γ-AL2O3 FOR IRAQI NAPHTHA TRANSFORMATION
Main Article Content
Abstract
Light naphtha treatment was achieved over 0.3wt%Pt loaded-alumina, HY-zeolite and Zr/W/HY-zeolite catalysts at temperature rang of 240-370°C, hydrogen to hydrocarbon mole ratio of 1-4 0.75-3 wt/wt/hr, liquid hourly space velocity (LHSV) and at atmospheric pressure.
The hydroconversion of light naphtha over Pt loaded catalyst shows two main reactions; hydrocracking and hydroisomerization reactions. The catalytic conversion of a light naphtha is greatly influenced by reaction temperature, LHSV, and catalyst function. Naphtha transformation (hyroisomerization, cracking and aromatization) increases with decreasing LHSV and increasing temperature except hydroisomerization activity increases with increasing of temperature till 300°C then began to decrease due to the formation of hydrocracking reaction. The investigation of Pt containing catalysts under study shows a very high hydrogenlysis activity , due to presence of metal component (i.e. Zr, W) which enhances the rate of paraffin isomerization and cracking.The hyroisomerization and the hydrocraking activities can be arranged as follows,.Pt/Zr/W/HY > Pt/HY > Pt/γ-Al2O3
The results showed that, Pt/γ-Al2O3 has higher activity for the direct dehydrogenation of C6 and C7 paraffin's present in naphtha to aromatics than Pt/HY and Pt/Zr/W/HY. This was due to pore volume catalyst ,the aromatics compounds increased as the pore volume increased.
Article Details
How to Cite
Publication Dates
References
Alvarez F., F.R.Ribeiro, G.Perot, Thomazeau, and M.Guisnet, 1996, “Hydroisomerization and hydrocracking of alkanes” , J.cat., 162, 174-180.
Eder F., Stockenhuber M., Lercher J.A.,1997 , "On the role of pore size and tortuosity for sorption of alkanes in molecular sieves ", J. Phys. Chem. B: 101, 5411-5419 .
Gauw F.J.M., Grandell J., Santen R.A., 2002, “The intrinsic kinetics of n-hexane isomerization catalyzed by Pt loaded solid acid catalyst”, J. Cat. 206, 295-304.
Gluseppe E. Glannetto, Guy R. Perot, and Michel R. Gulenet, 1986, “Hydroisomerization and hydrocracking of n-alkanes.1. Ideal hydroisomerization PtHY catalysts”, Ind. Eng. Chem. Prod. Res. Dev., 25, 481-490.
Hollo, J. Hancsok, D. Kallo, 2002, “Kinetics of hydroisomerizaion of C5-C7 alkanes and their mixture over platinum containing mordenite” A Applied Cat. A: General, 229, 93-102.
Jan-Ku, Chen, A.M. Martin, Young Gull Kim and Vijay T. John, 1988, “Mechanical study of isomerization of n-hexane”, Ind. Eng. 27, 401-409.
Jeong Kyu Lee, Hyun-ku Rhee, 1997, “Characteristics of Pt/HY-beta and Pt/H-mordenite catalyst for the isomerization of n-alkane”, Catalyst Today, 38, 235-242.
Jolly, J.Saussey, M. Bettahar, J.C. Lavalley, 1997, “Reaction mechanisms and kinetics in n-hexane cracking”, 156, 71-96.
Lawlor, Lawrence J., Marphy, William J., 1988, “Naphtha isomerization using a medium”, US patent, 4734539.
Masologites., George,1987, “Method of treating a used Pt group alumina catalyst with a metal promoter”, US patent, 4070306.
Mohamed L, Kh. and Ahmed H.S., 2004, “Isomerization of light over Pt containing support”, Egypt J. chem. 47, 3, 293-303.
Rafael Roldan, Anderew M. Beale, Manuel S. S., Francisco., Romero, Cesar, Juan P., Gopinathan,2008, “Effect of the impreantion order on the nature of the metal particles”, J. Cat., 254 ,12-26.
Srikant Gopal, 2003, “Synthesis, Modification, Characterization and catalytic study of zeolite” Ph.D. Thesis, university of cininnati.
Ward, J.W.,1993,”Fuel Process Technol”,35,55.
Williams B.A, W. Ji, Miller, Snurr, 2000, “Evidence of a different reaction mechanisms during the cracking of n-hexane” Applied Cat. A: General, 203,179-190.
Yan Liu,Yejun Guan,Can Li, Juan L.,Geok J., Eng Chew, Fethi K.,2006,"Effect of ZnO additives and acid treatment on catalytic performance of Pt/W/Zr for heptane isomerization,"J. of cat.244,17-23.