INVESTIGATION OF THE SHELF LIFE OF THE OPTIMIZED PROCESS OF BIODIESEL FROM SHEA NUT OIL
Abstract
ABSTRACT
This research investigates the shelf life of biodiesel produced from Shea nut oil, a
renewable & 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 FFA content, Shea nut oil was processed in
two steps: esterification followed by 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 1.5-hour transesterification
reaction which reduced the free fatty acids to the acid value of 0.945 mg KOH/g &
(FFA) content of 0.4725% indicating a low level of acidity. The properties of the
produced biodiesel were very similar & in line with ASTM standard. After optimizing
the process for biodiesel production, with four key parameters were analyzed: catalyst
loading at around 6.05, reaction time 75.95 minutes, temperature 43.81°C, produced
biodiesel yield of 91.45%. Biodiesel oxidizes, forming peroxides & other degradation
products that degrade fuel quality over time. This study examined the oxidation stability
using the Rancimat method & the stability times of the biodiesel with & without
antioxidants at week 0, week 2, week 4, week 6, & week 8 were 160, 160, 140, 120, &
100 minutes respectively, & with antioxidants at week 0, week 2, week 4, week 6, &
week 8 were 4.25, 4.00, 3.75 hours. The WPO biodiesel production was optimized
using the Design Expert version 13.0.6. The optimization was carried performed using
the response surface methodology (RSM). The reaction temperature (30 to 90 oC),
reaction time (15 to 120 minutes), & catalyst loading (1 to 10 wt%) were the parameters
used. The GC-MS analysis of the biodiesel sample revealed a mixture of mostly fatty
acid methyl esters (FAMEs), with methyl oleate, methyl stearate, & methyl laurate
being the most abundant components. These compounds are indicative of biodiesel
produced from feedstocks with a high content of oleic & stearic acids, which are
common in
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