الفهرس 
Natural Gas in Egypt
Ethylene ProductionOnly 14 pages are availabe for public view
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Abstract
The direct conversion of natural gas (methane) into hydrogen and valuable chemicals under nonoxidative conditions is a process severely limited thermodynamically. However, it is a very important process has attracted significant interest since 1993. The reaction is a thermodynamically admissible process only when carried out at high temperature in presence of bifunctional heterogeneous catalysts. The process applied natural gas conversion to ethylene, benzene, and little naphthalene via using a fixed bed flow reactor at 700°C and gaseous hourly space velocity (GHSV) of 1500 ml g-1 h-1 at time-on-stream up to 240 min. Different types of catalysts have been prepared to examine their promoting or inhibiting effects on the various reactions taking place during methane conversion.
To shed light on the role of the support type in natural gas conversion, Mo/SiO2 was tested and found of very low activity, substantiating the necessity for a zeolitic support. Also, to shed light on the effectiveness of the metal (Mo), the unloaded H-ZSM-5 was tested as a catalyst and found almost inactive.
The process also compares two types of zeolite support H-ZSM-5 with HBEA and revealing the superiority of the former zeolite.
The most prestigious catalyst applied in natural gas (methane) non-oxidative conversion to petrochemicals; 6%Mo/H-ZSM-5 prepared by the physical mixing of MoO3 and HZSM-5 exhibits a better performance compared with those prepared by the impregnation method.
The influence of adding 3%Cr, and W (metals of group VI),and 3%Fe, Co, Ni, Cu, and Zn (metals of period IV) into 3%Mo/HZSM-5 catalyst on methane aromatization reaction were investigated to examine their promoting or inhibiting effects on the various reactions taking place during methane conversion. The experimental results showed that using a Zn-Mo and Cr-Mo combination on H-ZSM-5 zeolite support are promoted the dehydrogenation and dissociation of methane and give a higher conversion of the natural gas to aromatics than the base catalysts; 6%Mo/HZSM-5, with superiority of Zn, indicating that Zn is successful promoter for Mo in the natural gas conversion to aromatics. However, Cr-Mo catalyst achieves the lowest coke deposition on the catalyst during methane non-oxidative conversion.
On the other hand W, Fe, Co, and Ni-Mo catalysts exhibit high coke deposition and inhibit the reaction activity. While Cu-Mo catalyst exhibits high reaction activity towards ethylene, with low tendency to coke formation.
Characterization of the catalysts using XRD, and TGA were investigated.