Investigation of the Shelf Life of the Optimized Shea Nut Biodiesel

This study investigates the shelf life of Biodiesel produced from Shea nut oil, a
renewable and sustainable feedstock. Biodiesel is prone to oxidation due to its
unsaturated fatty acid content. In the current work an attempt was made to produce
biodiesel from Shea nut oil, due to its high Free Fatty Acid content, Shea nut oil was
processed in two steps: Esterification and Transesterification. 500g of Shea nut oil
was esterified with 25wt% of methanol to oil ratio (125grams) using 1.0wt%
H2SO4(5grams) as catalyst constant temperature 60°c for 1.5hours Esterification
reaction which reduced the free fatty acid to 0.46% the acid value of 1.86mg KOH/g
indicating a low level of of acidity. The properties of the produced biodiesel were
very similar and in line with ASTM Standards. After optimizing the process for
biodiesel production, with four key parameters were analysed; catalyst loadings at
around 6.05, reaction time 75.95 minutes, temperature 43.81°c, produced biodiesel
yield of 91.45%. Biodiesel oxidizes, forming peroxides and other degredation
products that degrade fuel quality over time. This study examined the oxidation
stability using the Rancimat method analysis and oxidation stability times of the
biodiesel with and without antioxidants at week 0, week 2 week 4, week 6, week 8
were (4.2, 4.2, 4.2, 3.95, 3.7) hours for inhibited and (180, 160, 140, 120, 100) munites
for uninhibited respectively. The WPO biodiesel production was optimized using the
Design Expert version 13.0.6. The optimization process carried out was performed
using the response surface methodology (RMS). The reaction temperature (30 to
90°c), reaction time of (15 to 120 minutes), and catalyst loadings of (1 to 10 wt%).
Were the parameters used and a biodiesel yield of 130.06% was obtained.