Process Optimization for Biodiesel Production from Corn Oil and Its Oxidative Stability

Table 4

Quality control of corn oil biodiesel fuels used in this study before and after storage time of 30 months compared to EN 14214

Properties	Unit	Corn biodiesel before storage	Corn biodiesel after storage		Specification EN 14214
			Under argon atmosphere	Under normal oxygen atmosphere
Viscosity at 40°C	mm^2/s	4.14	4.72	5.82	3.5–5.0
Density at 15°C	g/cm^3	0.865	0.871	0.895	0.86–0.90
Water content	wt%	0.15	0.21	0.29	<0.5
Biodiesel yield	wt%	99.48	98.7	96.23	>96.5
Monoglyceride content	wt%	0.40	0.27	0.3	<0.80
Diglyceride content	wt%	0.11	0.1	0.1	<0.20
Triglyceride content	wt%	0.0	0.0	0.0	<0.20
Free glycerol	wt%	0.01	0.01	0.01	<0.02
Acid value	mg KOH/g	0.047	0.21	0.7	<0.5
Iodine value	mg I2/g	126.6	98.4	80	<120
Peroxide value	meq/Kg	3.0	14	31.8	—
Cloud point	°C	−5	−4	−3	—
Pour point	°C	−6	−6	−5	—
Cold filter plugging point	°C	−8	−8	−9	<−7