BATCH AND CONTINUOUS PYROLYSIS OF RUBBER WOOD SAWDUST FOR PRODUCTION OF BIO-ENERGY AND BIO-CHEMICALS

The prospect of energy generation and chemical derivation based on biomass utilization is drawing great attention. One of the promising technologies to generate valuable fuels and chemical products from biomass is through a pyrolysis process. It is a heating process of organic materials at a medium temperature between 400 to 800 °C under the absence of oxygen and in a short retention time. It converts biomass into liquid (bio-oil), solid (bio-char), and gas (pyrolysis gas) products. In this research, rubber wood sawdust (RWS) residue with a size range of 0.15 to 0.50 mm was pyrolyzed by two methods of batch and continuous pyrolysis. The first part of the study is to determine the influence of pyrolysis temperature (450, 500, 550, and 600 °C) by using a drop-type fixed bed pyrolyzer. When pyrolysis temperature increased, the yield of bio-char reduced from 38.7 to 25.7 wt%, while bio-oil and noncondensable gas (NCG) yields increased. However, at a certain high temperature (550 °C), the bio-oil yield started to decrease because secondary reaction happened and more gas was produced. To evaluate the effect of fluidization gas velocity, Ug (3.64, 4.55, and 5.46 cm/s), the second part involved continuous pyrolysis of RWS via a bubbling fluidized bed pyrolyzer. As the Ug was increased, the bio-oil yield increased from 26.2 to 29.3 wt%, but the yield of pyrolysis gas declined from 47.6 to 42.8 wt%. Physicochemical characteristics of RWS biomass and pyrolysis products were determined using various analyses. Bio-oils produced in this study had high percentage of oxygen (52 to 73 wt%) and hydrogen (6 to 11 wt%) than the RWS feedstock and char, indicating high water content (33 to 76 wt%) which considerably decreased the calorific value (CV). By applying fractional condensation setup, water content of bio-oil fractions was reduced. Acetic acid, phenol, cyclopentanone, and tetrahydrofuran (THF) were the main bio-oil compounds. The bio-char product had significantly higher carbon composition (70 to 78 wt%) and CV (26 to 30 MJ/kg) when compared to the biomass feedstock and bio-oil product. The major components of pyrolysis gas were CO2 (43 to 53 wt%) and CO (33 to 37 wt%)