Research Article
Extraction of Municipal Sewage Sludge Lipids Using Supercritical CO2 for Biodiesel Production: Mathematical and Kinetics Modeling
Table 3
Physicochemical properties of ScCO2 extracted lipids from municipal sewage sludge (MSS) and sewage sludge biodiesel.
| Properties | Unit | Lipids | Biodiesel | ASTM D6751 | EN 14214 |
| Yield | % | 26.54 ± 0.21 | 84 ± 2 | — | — | FFAs | % | 0.81 ± 0.16 | 0.16 ± 0.06 | — | — | Kinematic viscosity at 40 ℃ | mm2/s | 6.18 ± 0.21 | 4.10 ± 0.14 | 1.9–6.0 | 3.5–5.0 | Density at 15 ℃ | kg/m3 | 840 ± 6 | 865 ± 4 | 880 | 860–900 | Saponification value | mgKOH/g | 196 ± 2.54 | 158 ± 2.54 | — | — | Acid value | mgKOH/g | 0.50 ± 0.04 | 0.20 ± 0.02 | ≤0.5 | ≤0.5 | Heating value | MJ/kg | 39.20 ± 1.4 | 39.64 ± 2.86 | — | — | Cetane number | — | 56.10 ± 2.7 | 56 ± 2 | ≥47 | ≥51 | Pour point | ℃ | 8.5 ± 0.5 | −10.50 ± 0.65 | −15 to 16 | — | Cloud point | ℃ | 12.5 ± 0.5 | −2.50 ± 0.14 | −3 to 12 | — | Heating value | MJ/kg | 39.20 ± 1.4 | 39.64 ± 2.86 | — | — | Iodine number | g I2/100 g | 69.10 ± 2.80 | 75.9 ± 2.34 | — | ≤120 | Flash point | ℃ | 166 ± 2.10 | 140 ± 4 | ≥130 | ≥101 |
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