Application of Response Surface Methodology for Ethanol Conversion into Hydrocarbons Using ZSM-5 Zeolites

The ethanol conversion into hydrocarbons (light olefins and aromatics) using alkali-treated HZSM-5 with different SiO2/Al2O3 ratios (23, 38, and 53) zeolites was evaluated. The desilicated SAR 38 zeolite exhibited significant growth on the external surface area (61-212 m(2)/g) and the mesopore volume (0.07-0.37 cm(3)/g) without significate reduction on XRD crystallinity (93%). All catalysts were active on the ethanol conversion into hydrocarbons. At the same set of variables, the alkali-treated HZSM-5 zeolites showed a better conversion and a high selectivity to C-4-C-9 hydrocarbons when compared to the parent microporous zeolites. Only the parent HZSM-5 zeolite (SAR 53) was chosen for the statistical study using the standard response surface methodology in combination with the central composite design. It was found that maximum BTEX (benzene, toluene, ethylbenzene, and xylenes) and minimum ethylene production were reached for the following conditions: temperature 450 degrees C, pressure 20 bar, and WHSV (weight hourly space velocity) 5 h(-1).