Form the previous literature It was observed that RHA was
Form the previous literature, It was observed that RHA was burnt in the range of 500 °C to 700 °C, with high content of quartzite silica was used is a partial replacement of cement in mortar and in concrete. The results shown an excellent behavior in enhancing the mechanical properties of cement mortar and concrete ,  but no specific literature was found on RHA with high crystalline silica content.
Materials and methods
Conclusions In this paper, the performance of all samples of RHA obtained from method A and method B were studied. Some of the substantial conclusions drawn are:
Declaration of interest
Introduction Several studies have been developed in catalyst screening to produce specific chemicals and/or bio-oil with improved physical and chemical properties by catalytic pyrolysis . Different materials have been examined for use as a catalyst and special attention has been given to zeolites (ZSM-5, HY, Beta, Mordenite) due to their ability to produce aromatics , , , . Mesoporous materials have also been studied, but catalytic pyrolysis studies using metal oxide, low-cost alternative materials for catalytic support and catalyst materials derived from rice husk ash (RHA) are very limited. Among metal oxides, tungsten materials are an interesting solid whose catalytic activity depends on the WOX surface density, activation temperature and the active phase interaction with the support, which can generate Bronsted Cyt387 sites by load balancing in heteropolytungstate , , . The acidity, redox ability and thermal stability of this material have attracted great interest in studying its activity in catalytic pyrolysis and/or conversion of biomass pyrolysis products into chemicals. In addition to the choice of catalyst, biomass characteristics have great influence on pyrolysis products. Lignocellulosic biomass with low lignin and ash content and a high content of volatile material when submitted to pyrolysis show a high yield of bio-oil. Among these, low-priced crops that present high production levels of dry matter/ha/year such as Miscanthus spp., Switchgrass (Panicum virgatum L.), and sugar cane bagasse (Saccharum officinarum L.) have attracted great interest. Few studies have been developed about the thermochemical processes involving Elephant Grass. This biomass is a perennial native grass of Africa that has attracted interest as an energy crop because of its high productivity, short production cycle, low requirement of additional nutrients for growth, easy adaptation to climate and soil conditions of different places, good energetic properties and also because it is widespread throughout different countries, including Brazil , . This study aims to analyze the energetic proprieties of Elephant Grass (EG) through its characterization, its conventional pyrolysis products and its catalytic pyrolysis products using WO3 supported on rice husk ash (RHA) silica and RHA-MCM-41 mesoporous materials. In addition, the study also evaluates the influence of WO3 content, support material and catalytic bed temperature on the formation of deoxygenated compounds by ex situ catalytic pyrolysis.
Materials and methods
Results and discussion
Conclusion EG has been shown as a potential energy crop due to its characterization results, easy cultivation and fast growth. It produces many oxygenated compounds (phenol, ketones, furans) that were converted into some aromatic compounds after catalytic pyrolysis. The deoxygenated reaction pathways were difficult to identify, but the main influence on the deoxygenation reactions of pyrolysis products was the WO3 active sites promoted by the redox ability of the catalyst, since aromatic compound yield increases with the increased WO3 content on the catalyst. Increasing the catalytic bed temperature has a significant influence on aromatic compound yield, mainly on the yield of benzene, toluene and styrene which are usable products. The WO3 supported on rice husk ash (RHA) has been shown to be a low-cost catalyst for converting lignocellulosic biomass pyrolysis products into aromatics.