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Chemical Technology • February 2015
in the oil and the oil was transferred into a beaker in
order to titrate the oil.
• The food chunks were disposed of in a safe manner.
Indicator solution preparation
• 0,5 g of phenolphthalein was weighed.
• A 50 % ethanol solution was prepared by adding 50 ml
of water into 50 ml of ethanol.
• The phenolphthalein was then dissolved into the solution.
Oil titration
• A titration solution was prepared by dissolving 1 gram of
catalyst, ie, potassium hydroxide or sodium hydroxide in
a litre of water.
• 10 ml of isopropyl alcohol was then poured in a 100 ml
beaker, a syringe was used to transfer 1 ml of oil into
the same beaker and the contents in the beaker were
mixed for 5 minutes.
• 2-3 drops of the pH indicator were added to the mixture.
• A burette was then used to add the titration solution to
the mixture until the solution turned pink, the amount
or volume of the titration solution added to the mixture
was recorded.
• The titration was repeated three times and the average
volume was calculated.
• The average volume was used to calculate the amount
of catalyst required.
• In order to calculate the required amount of the catalyst,
the average volume was added to the base amount of the
catalyst and the total wasmultiplied by the volume of the oil.
Biodiesel production
• 400ml of oil was used for all the experiments. The volume
of alcohol used varied from experiment to experiment.
• The required amount of alcohol was poured into a mea-
suring cylinder.
• The required amount of catalyst was weighed and added
to the alcohol until the catalyst dissolved completely.
• The oil was heated to the required temperature of 60°C
using a magnetic stirrer.
• The alcohol solution was added to the heated oil mixture
while it was allowed to react for 30 minutes or so whilst
it was constantly stirred and heated.
• The reacted mixture was poured into a separatory funnel
and allowed to settle for approximately 12 hours.
• The glycerin layer was then drained out.
• Water was added to the biodiesel to remove excess
methanol and glycerin, the washing was repeated mul-
tiple times until the water at the bottom was clear.
• The water was drained from the diesel and poured into
a washwater collection container.
• The biodiesel was then poured into a beaker and heated
for 15 min to allow the remaining water to evaporate.
Table 1 summarises the actual parameters or volumes that
were used for all six experiments. Each experiment was
done using 400 ml of oil.
Results and discussions
Biodiesel experiment results
Table 2 shows the raw material quantities as well as the
amount of the product, by product and waste generated
from alternative biodiesel experiments. It can be seen from
the table that experiment 3 used the most water to wash
out the impurities from the biodiesel and experiment 5
used a smaller quantity of water in comparison to all the
experiments. Experiment 4 which used ethanol and KOH
as a catalyst gave the highest yield of biodiesel; experi-
ment 1 gave the lowest biodiesel yield and the highest
glycerol yield.
Life Cycle Analysis
Goal and scope
The life cycle assessment was carried out using the SimaPro
7.3.3. and ECO-Indicator 99 (E) V2.08 / Europe EI 99 E/E
assessment methods, the analysis was done on the com-
plete life cycle of the biodiesel produced fromwaste cooking
oil using different alcohols, ie, methanol and ethanol and
different catalysts, ie, KOH and NaOH. The SimaPro soft-
ware program compared the environmental impact of the
biodiesel alternative production routes on a basis of 1 kg
of biodiesel produced (Functional unit).
Data used for the assessment was collected from the
lab experiments (quantities of the raw materials, product,
by-product, waste and electricity consumed), internet as
well as the SimaPro 7.3.3 database. For each experiment
Experiment
Temperature
Catalyst
Alcohol
Alcohol volume (ml)
Pressure (atm)
1
65
KOH
Ethanol
160
1
2
55
KOH
Methanol
80
1
3
65
KOH
Methanol
200
1
4
60
KOH
Ethanol
200
1
5
60
NaOH
Methanol
200
1
6
60
KOH
Methanol
160
1
Experi-
ment 1
Experi-
ment 2
Experi-
ment 3
Experi-
ment 4
Experi-
ment 5
Experi-
ment 6
Products
Biodiesel (ml)
250
280
310
340
320
300
Glycerol (ml)
200
180
152
195
150
160
Feed
Waste cooking oil (ml)
400
400
400
400
400
400
Methanol (ml)
80
200
200
160
Ethanol (ml)
160
200
NaOH (g)
3.4
KOH (g)
9.26
9.26
9.196
9.26
9.26
Water (ml)
2000
1580
3000
1200
640
1090
Electricity (kWh)
0.5
0.5
0.417
0.458
0.417
0.708
Waste
Wash water (ml)
2000
1580
3000
1200
640
790
Catalyst (g)
9.26
9.26
9.196
9.26
3.4
9.26
Table 1: Conditions used to carry out the experiments.
Table 2: Summary of the inputs and outputs obtained from the biodiesel experiments