11.08.2015   BIOFUELS

Production of microalgal biodiesel

Microalgal biodiesel will need to comply with the standard EN 14214 in the EU and ASTM D 6751 in the USA before it can be universally accepted. Microalgal oils tend to contain more polyunsaturated fatty acids than plant oils, and those with four or five double bonds are more susceptible to oxidative degradation. However, the biodiesel produced from oil extracted from C. protothecoides had characteristics which were simi­lar to diesel (Miao and Wu, 2006) apart from a slightly higher viscosity (Table 7.8).

Table 7.8. Comparison of the properties of microalgal biodiesel and diesel. (From Miao and Wu, 2006; Xu et al., 2006; Stanhope-Seta, 2007.)

Properties

Microalgal biodiesel

Diesel

En 14214 specifications

Density (kg/l)

0.864

0.838

0.86-0.90

Viscosity (mm2 s-1 cSt at 40°C)

5.2

1.9—4.1

3.5-5.0

Flash point (°C)

115

75

>101

Pour point (°C)

-12

-50-10

—

Cold filter plugging point (°C)

-11

-3-6.7

Summer — 0 Winter -15

Acid value (mg KOH/g)

0.374

Max 0.5

0.5

Heating value (MJ/kg)

41

40-45

—