Effect of Water and Glycerol in Deoxygenation of Coconut Oil over Bimetallic NiCo/SAPO-11 Nanocatalyst under N2 Atmosphere

Abstract

The catalytic deoxygenation of coconut oil was performed in a continuous-flow reactor over bimetallic NiCo/silicoaluminophosphate-11 (SAPO-11) nanocatalysts for hydrocarbon fuel production. The conversion and product distribution were investigated over NiCo/SAPO-11 with different applied co-reactants, i.e., water (H2O) or glycerol solution, performed under nitrogen (N2) atmosphere. The hydrogen-containing co-reactants were proposed here as in-situ hydrogen sources for the deoxygenation, while the reaction tests under hydrogen (H2) atmosphere were also applied as a reference set of experiments. The results showed that applying co-reactants to the reaction enhanced the oil conversion as the following order: N2 (no co-reactant) < N2 (H2O) < N2 (aqueous glycerol) < H2 (reference). The main products formed under the existence of H2O or glycerol solution were free fatty acids (FFAs) and their corresponding Cn−1 alkanes. The addition of H2O aids the triglyceride breakdown into FFAs, whereas the glycerol acts as hydrogen donor which is favourable to initiate hydrogenolysis of triglycerides, causing higher amount of FFAs than the former case. Consequently, those FFAs can be deoxygenated via decarbonylation/decarboxylation to their corresponding Cn−1 alkanes, showing the promising capability of the NiCo/SAPO-11 to produce hydrocarbon fuels even in the absence of external H2 source.

The Effect of Activated Carbon Pellet on Hydrothermal Decarboxylation of Palm Olein into Renewable Diesel

“…( 10). 22) 100 × = ∑ ∑ P D n n X (10) where, nD = total area of alkene (C12-C18) and total area of alkane (C12-C18) in product, nP = total area of the product. Thus, The renewable diesel selectivity (SD) was determined by eq.…”

“…DCO/DCO2 is widely investigated among the three DO routes, especially DCO2 since the H2 consumption is the lowest 10) . In addition, both DCO/CO2 can be run under milder operating conditions than HDO, which reduces hydrogen usage, longer catalyst life, and lower moisture content 11) .…”

“…Adding a co-reactant as the hydrogen donor has also been investigated by many in the particular organic solvent, water, and compared under inert conditions (nitrogen gas only). Some studies mentioned that the co-reactant addition increased oil conversion in the following sequence: N2 < N2 with H2O < N2 in aqueous glycerol < H2 10) . Still, glycerol or any organic solvent has the foremost drawbacks regarding cost and environmental aspects and thus making water an attractive co-reactant choice to explore.…”