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The present study describes the stability of oxalic acid treated ZnO/CuO/HZSM-5 catalyst for the conversion of methanol to gasoline range hydrocarbons. A 0.5 wt % ZnO/7 wt % CuO/HZSM-5 catalyst was prepared by the wet impregnation method followed by dealumination using oxalic acid. Fresh and used catalysts were characterized by X-ray diffraction, scanning electron microscopy, surface area analysis, pore size analysis, thermogravimetric analysis, NH3 temperature programmed desorption, and X-ray photoelectron spectroscopy. All the kinetic experiments were carried out in an isothermal fixed bed reactor at 673 K. The major liquid reaction products were cyclopentene, n-hexane, 1-octene, cycloheptane, 2,5-dimethylhexane, n-nonane, cyclohexane, ethylbenzene, xylene, toluene, isopropylbenzene, trimethylbenzene, and tetramethylbenzene. The effect of run time was also studied to investigate the effect of oxalic acid treatment on catalyst stability. The oxalic acid treated catalyst was more resistant to deactivation compared to the untreated 0.5 wt %/ZnO 7 wt % CuO/HZSM-5 catalyst.

As the need for petroleum products is increasing, it has led to increased crude oil prices. For an alternative approach, much research has been done in the field of catalytic conversion of methanol-to-hydrocarbon (MTH). The MTH process is suitable, which converts methanol directly into gasoline and other valuable hydrocarbons. The review provides information about methanol to olefins (MTO), methanol to aromatics (MTA), and MTH processes involved in converting oxygenates into hydrocarbons and information regarding methanol synthesis. It reviews the effect of physicochemical properties such as acidity, pore diameter, surface area, the catalyst’s lifetime, and process conditions on MTH transformation. The article shows different methods that are employed to change the zeolite’s acidic properties. These methods include acidic, alkaline, and steam heat treatment, which are also discussed. The results obtained after catalytic cracking of methanol were also validated by using several kinetic models proposed worldwide.

M ethanol obtained from coal and natural gas can be used as a raw material for synthesis of methanol. Methanol is used as a raw material for the production of olefins and other hydrocarbons using zeolite catalysts. Zeolites such as HZSM-5 have attracted many researchers to obtain yield of gasoline range hydrocarbons. Its nature and extent of reaction depend on acid strength, acid site density, catalyst topology, temperature, pressure, space velocity and other process conditions (Alkawaldeh et al., 2003;Cañizares et al., 1998;Marchi and Froment, 1993;Mikkelsen and Kolboe, 1999). The influence of metal/metal oxide incorporation over the surface of zeolite enhanced the methanol conversion and hydrocarbon yield (Zaidi and Pant, 2004;Al-Jarallah et al., 1997;Freeman et al., 2002;Kang, 2000;Zhu et al., 2000). The catalytic conversion of methanol to gasoline range hydrocarbon over CuO, ZnO doped HZSM-5 catalyst increases the hydrocarbon yield as compared to unmodified HZSM-5 (Zaidi and Pant, 2004). It has been reported that the long life of zeolite catalysts for methanol conversion to gasoline (MTG) was due to the variation in physicochemical properties of ZnO over CuO/HZSM-5 (Stöcker, 1999;Haw et al., 2003). Arstad et al. (2004) studied the chemistry and mechanism of reaction of methanol to hydrocarbon at various reaction parameters. In a subsequent study, various techniques have been used to characterize zeolites catalyst and to study the impact of catalytic action with different type to zeolites catalysts (Donk et al., 2003; A number of CuO/HZSM-5 catalysts have been studied in a small scale fixed bed reactor for the conversion of methanol to gasoline range hydrocarbons at 673 K and at one atmospheric pressure. All the catalysts were prepared by wet impregnation technique. The copper oxide loading over HZSM-5 (Si/Al=45) catalyst was studied in the range of 0 to 9 wt%. XRD, surface area analyzer, metal trace analyzer, SEM techniques and TGA were used to characterize the catalysts. Incorporation of CuO onto HZSM-5 zeolite significantly increased conversion and liquid hydrocarbon product yields. The major liquid products of the reactions were ethyl benzene, toluene, xylene, isopropyl benzene, ethyl toluene, trimethyl benzene and tetramethyl benzene. The maximum methanol conversion and hydrocarbon product yield was obtained at a copper oxide loading of 7 wt%. Effect of run time on conversion and product distribution was also investigated to compare the performance of these catalysts and coke on the catalyst was determined. Effect of space-time and temperature on methanol conversion and products yield with 7 wt% CuO/HZSM-5 has also been investigated and analyzed qualitatively.On a étudié plusieurs catalyseurs de CuO/HZSM-5 dans un réacteur à lit fixe de petite échelle pour la conversion méthanol en hydrocarbures de type carburants à 673 K et à pression atmosphérique. Tous les catalyseurs ont été préparés par la technique d'imprégnation humide. La charge en oxyde de cuivre sur le catalyseur HZSM-5 (Si/Al=45) a été étud...

Abstract-A series of NiO/ZnO/HZSM-5 catalysts were prepared by impregnation method with varying ZnO loading ranging from 0-2 wt% and keeping 4 wt% NiO loading constant. It was found that the ZnO/NiO modified HZSM-5 catalyst was highly active and selective towards ethanol conversion to hydrocarbons at 410 °C, WHSV = 3.5 hr -1 and pressure = 1 atm. A comparison has been done to study conversion and yield of different wt% of ZnO/NiO over HZSM-5 catalyst. The performance of catalysts was evaluated by conducting experimental run in fixed bed reactor under identical conditions. The major products of the reaction were methane, ethylene, propylene, ethylmethyl ether, toluene, ethyl benzene, xylene, isopropyl benzene, ethyl toluene, and trimethyl benzene and tetra methylbenzene.It was observed that ZnO and NiO modified HZSM-5 reduces the rate of deactivation of catalyst. It was also observed that 1.5 wt% ZnO/4 wt% NiO/ HZSM-5 catalyst was highly reactive for ethanol conversion to hydrocarbons. In addition HZ (1.5 Zn/4 Ni) modified catalyst suppressed the coke deposition without affecting product yield and conversion.Index Terms-Ethanol, HZSM-5, catalyst deactivation, doping with NiO and ZnO.