Maximizing Energy Recovery from Beauty Leaf Tree (Calophyllum inophyllum L.) Oil Seed Press Cake via Pyrolysis

Abstract

This study optimizes pyrolysis conditions that will maximize energy recovery from the Beauty Leaf Tree (BLT; Calophyllum inophyllum L.) oil seed press cake. Response surface methodology (RSM) was used to determine the behavior of pyrolysis coproducts (solid, liquid and gas) at various temperatures and residence times. One significant discovery was that 61.7% of the energy (of the whole BLT oil seed) was still retained in the BLT oil seed cake after oil extraction. Controlled pyrolysis produced various proportions of biochar, bio-oil and syngas coproducts. Predictive models were developed to estimate both the mass and energy yields of the coproducts. In all experimental runs, the biochar component had the highest mass yield and energy content. Biochar mass yields were high at the lowest operating temperature used, but the energy yields based on a high heating value (HHV) of products were optimal at higher operating temperatures. From the RSM models, energy from the biochar is optimized at a pyrolysis temperature of 425 °C and 75 min of exposure time. This biochar would have a heating value of 29.5 MJ kg−1, which is similar to a good quality coal. At this condition, 56.6% of the energy can be recovered in the form of biochar and 20.6% from the bio-oil. The study shows that almost all the energy present in the feedstock can be recovered via pyrolysis. This indicates that commercial biodiesel producers from BLT oil seed (and other oil seed) should recover these additional valuable energies to generate high value coproducts. This additional efficient energy conversion process via controlled pyrolysis will improve the overall economics and the feasibility of 2nd generation biodiesel production from BLT—a highly potential species for cultivation in many tropical countries.