Chemical Technology February 2015

Experiment

Temperature

Catalyst

Alcohol

Alcohol volume (ml)

Pressure (atm)

1 2 3 4 5 6

65 55 65 60 60 60

KOH KOH KOH KOH

Ethanol

160

1 1 1 1 1 1

Methanol Methanol

80

200 200 200 160

Ethanol

NaOH

Methanol Methanol

KOH

Table 1: Conditions used to carry out the experiments.

Experi- ment 1

Experi- ment 2

Experi- ment 3

Experi- ment 4

Experi- ment 5

Experi- ment 6

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. 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 Results and discussions Biodiesel experiment results

Products Biodiesel (ml)

250

280

310

340

320

300

200

180

152

195

150

160

Glycerol (ml)

Feed Waste cooking oil (ml)

400

400

400

400

400

400

80

200

200

160

Methanol (ml)

160

200

Ethanol (ml)

3.4

NaOH (g)

9.26

9.26

9.196

9.26

9.26

KOH (g)

2000

1580

3000

1200

640

1090

Water (ml)

0.5

0.5

0.417

0.458

0.417

0.708

Electricity (kWh)

Waste Wash water (ml)

2000

1580

3000

1200

640

790

9.26

9.26

9.196

9.26

3.4

9.26

Catalyst (g)

Table 2: Summary of the inputs and outputs obtained from the biodiesel experiments

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

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Chemical Technology • February 2015