Characterization of non-oxygenates hydrocarbon product from the catalytic pyrolysis of rice straw

Abstract

The usage of fossil fuel as petrochemical feedstock becomes problems due to the depletion of its supply coupled with the issue of global warming and air pollution, thus a new alternative is needed. Lignocellulose biomass can be converted into hydrocarbons for the petrochemical industry’s feedstock through pyrolysis process, which is a thermal decomposition of biomass in an oxygen-free condition. The materials used in this experimental study consist of rice straw as the main feedstock, ZSM-5 as the catalyst. Rice straw is lignocellulose biomass that has the potential in Indonesia because of its abundant supply in many locations. Biomass catalytic pyrolysis was carried out using a fixed bed reactor with the varied ratios of ZSM-5 and biomass mixture and the products in the form of gaseous phase come out from the bottom of the reactor by flowing it into a glass test tube with a diameter of 2.5 cm. Pyrolysis process was carried out at temperature variations of 450°C, 500°C, and 550°C in a nitrogen gas flowing condition of 10-20 ml/minute. To detect the non-oxygenate hydrocarbon products, the sampling of the gas product was done by taken it using the glass syringe in the reactor bottom. The gas analysis was performed using Gas Chromatography-Mass Spectroscopy (GC-MS) and the calibration curve was then prepared to quantify the results by GC-MS analysis for various pyrolysis vapor compounds with their respective peak areas. With the variation of pyrolysis temperature, this study shows that the olefin group produced in catalytic pyrolysis neither does the conventional pyrolysis. But the pyrolysis produced the paraffin group in any type of pyrolysis condition process. This study also found that olefin group production was decreased in the longer time of stream reaction, while the aromatic group was increased. Generally, the amount of aromatic compound formation depends on catalyst ratio.