A review on catalytic upgrading of bio-oil produced from pyrolysis of biomass over the rice husk ash (RHA) and HZSM-5 catalyst

Biomass energy is one of the most widely explored research fields in energy and environmental science. The bio-oil can be produced from renewable biomass feedstock such as wood, grass, rice husk, corn stalk, and any agricultural waste. Any agricultural residues product as biomass waste in Asia Pacific countries like China, Japan, Indonesia, Pakistan, Bangladesh, Malaysia, .etc can be utilized as a renewable energy. In the other aspects, all agricultural residues are produced into untreated waste or burned waste that generates air pollution. Especially in Indonesia, there are any environmental impacts of open rice combustion closed to municipal or household area. Biomass can be utilized to produce bio-oil, a promising eco-friendly alternative energy source of renewable energy in the context of current energy scenarios for the limited crude oil. Rice husk is widely available agricultural residue, especially in Indonesia. There are high amounts of residues, and it is not utilized properly that producing air pollutants the open burning of rice residues. Renewable biomass sources can be converted to fuels and are a logical choice to replace oil after the upgrading process. In the end, it can be supported to the farmers in the rural areas where supply fuels to any agricultural engine such as tractor, harvesting machine, etc. In order to upgrade the bio-oil efficiently, two catalysts will discuss emphatically in this study: the rice husk ash (RHA) catalyst and the HZSM-5 catalyst. A review on the commercial catalyst such as HZSM-5 catalyst, is commonly used in bio-oil crack upgrading, and the non-commercial catalyst such as rice husk ash (RHA) to reduce the cost. After compared, a better-upgraded oil will produce. The reaction conditions and the reaction principle has been investigated as well. Hundreds of components in the raw bio-oil can be divided into 4 classes: small molecules, cyclopentanone, benzene, phenols and macromolecules. Small molecules are not the main cause of the catalyst deactivation. Phenols slightly deactivate the catalyst. The contact of macromolecules with zeolite is a big problem causing the deactivation. If phenol can be applied directly as an alternative to biodiesel, it is necessary to separate the phenol component from bio-oil. The ideal phenol separation method can be carried out by liquid-liquid extraction.