Fast pyrolysis of Vietnamese waste biomass: relationship between biomass composition, reaction conditions, and pyrolysis products, and a strategy to use a biomass mixture as feedstock for bio-oil production

Four types of Vietnamese waste biomass were investigated for bio-oil production using the fast pyrolysis technology. Feedstock chemical composition, product yields, and bio-oil physical properties have been systematically compared. The chemical composition and properties of Vietnamese resources of biomass are similar to those of the other biomass. The experimental results showed that all obtained bio-oils fulfilled the specifications for pyrolysis liquid defined as ASTM D7544-12 Standard. The biomass composition has strong impact on product yields, especially bio-oil formation. Higher contents of the three main components in the feedstock (i.e., cellulose, hemicellulose, and lignin) lead to a higher yield of bio-oil, whereas its high ash content caused a decrease in the bio-oil yield. As a result, the bio-oil yields from feedstock are in the following order: bagasse > corn cob > rice husk > rice straw. In addition, pyrolysis conditions (e.g., temperature and nitrogen flowrate), but not biomass preparation (e.g., material particle size), influence the bio-oil yield and its properties, as well. However, it has been found that this influence for rice husk and rice straw feedstocks is more prominent than for bagasse and corn cob. Finally, a strategy for an efficient usage of various waste resources for future biorefineries was proposed.