This design study uses a potassium hydroxide (KOH) catalyst and methanol to syn­thesise FAME based on Sakai et al.’s [29] biodiesel production model, which states that 100 parts of oil and 40 parts of methanol with a KOH catalyst will produce 92 parts of FAME and 21.5 parts of crude glycerol. The study makes use of partially recycled methanol feedstock whose composition is 24 parts of recycled methanol and 16 parts of fresh methanol. Figure 8 shows the transesterification model. Applying this model to the oil yields from the solvent extraction gives a daily biod­iesel production of ~7,158 kg/day and an annual production of ~2,360 tonnes. The yield of glycerol as a byproduct is ~1,673 kg/day.

1.6 Process Economics

Whilst the production of biodiesel from microalgae has been shown to be technically feasible, the viability of microalgal biodiesel as a practical alternative will be ulti­mately determined by its ability to become cost competitive with the current fuels.