Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2008
Student: OSMAN MUZAFFER AFYON
Supervisor: MELTEM DOĞAN
Open Archive Collection: AVESIS Open Access Collection
Abstract:Isobutene is the raw material of MTBE (methyl tert-butyl ether) and ETBE (ethyl tert-butyl ether) which are additive for gasoline to increase the octane number. One of the methods in production of isobutene is the process of dehydrogenation reaction taken place. Dehydrogenation reactions are equilibrium reactions. By removing the product hydrogen from the reaction medium it is possible to obtain higher conversion values as compared to equilibrium conversion. Membranes are used for this purpose. One of the techniques to prepare membranes is ELP (electroless plating) which is applicable to all kinds of support structure and which is a very cheap and simple technique. Electroless plating technique bases on the reduction of metallic salt complex by an autocatalitic reaction on the surface of the activated support. In an ELP technique, first of all porous glass support was cleaned and then activated. Lastly, plating steps were applied on the activated surface. PdCl2, hydrazine as a reducing agent and EDTA as a complexing agent were used in plating bath. Eight plating steps were applied on the porous glass support one of which held for two hours. Platings were carried out at a bath temperature of 35oC and at pH range of 10-11. First four platings were made without using osmotic flux effect. 3M sucrose solution was used in plating studies to create osmotic flux for the next two platings. Last two plating studies were also performed without creating osmotic flux. Plating thickness was determined as 85 μm after first four plating studies and 110 μm after the plating studies where osmotic flux effect was used. It was observed that there was significant amount of carbon on the surface. Therefore, two heat treatments were achieved at 500oC after sixth plating study. Carbon ratio was decreased to 31% while it was 44 % before heat treatments. Plating thickness was increased to 200 μm after last two plating studies. C amount on the surface was determined as 10 %, after heat treaments which were applied after eighth plating. Dehydrogenation of isobutane was examined in a fixed bed membrane reactor which was prepared using composite membrane synthezied. Pt/alumina (0.5% Pt) and pure chromium oxide were used as catalysts in reaction studies. Reactor temperature was 450oC and the pressure was fixed at a value a bit higher than atmosferic pressure (atmosferic pressure + 0,66 kPa). Isobutane conversions on pure chromium oxide and Pt/alumina were found as 17% and 20%, respectively.