Malee Tangsathitkulchai

Effect of reaction conditions on the catalytic esterification of bio-oil

Studies of bio-oil upgrading via esterification of palm shell bio-oil and alcohols employing acid catalysts were carried out in this work. The effects of esterification conditions on reaction conversion and product quality were investigated. Results indicated that esterification reaction using solid acid catalyst of Amberlyst15 enabled the conversion of organic acids in the bio-oil to esters and could also reduce certain amount of active aldehydes. The utilization of H2SO4 liquid catalyst was found to give higher conversion at the same reaction condition. Furthermore, higher reaction conversion to esters was achievable under conditions of higher temperature, longer reaction time, higher amounts of catalyst and alcohol and the use of shorter hydrocarbon chain of alcohol. Bio-oils, after being subjected to esterification, gave moderate heating value of 23–25 MJ/kg and improved fuel properties of decreased density, viscosity, carbon residue content, ash content, pour point and acidity.

Rheology and fuel properties of slurries of char and bio-oil derived from slow pyrolysis of cassava pulp residue and palm shell

Three bio-oil samples, namely, raw bio-oil from pyrolysis of cassava pulp residue (CPR), separated oil phase and aqueous phase of bio-oil from pyrolysis of palm shell (PS), were used as suspending media for preparing slurries of bio-oil and the co-product char. Rheologies of all tested slurries exhibited pseudoplasticity with yield stress and the degree of this non-Newtonian behavior depended on such parameters as slurry type, solid concentration, particle size and slurry temperature. Overall, char/bio-oil slurries gave better fuel properties including higher pH and reasonably high calorific value (18–32 MJ/kg) as compared to their bio-oil properties. Combustion of char/bio-oil slurries occurred in the temperature range similar to their solid char combustion and without ignition delay.