Exploratory study on internal recycling of crude glycerol for biodiesel production: Catalyst replacement
The present study evaluated the recycling of crude glycerol as source of catalyst for biodiesel production. For that purpose, two sets of experiments were conducted. In the first set (A), biodiesel was synthesized by conventional methanolysis of sunflower oil using NaOH as catalyst at 65°C...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Association of the Chemical Engineers of Serbia
2016-01-01
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| Series: | Chemical Industry and Chemical Engineering Quarterly |
| Subjects: | |
| Online Access: | http://www.doiserbia.nb.rs/img/doi/1451-9372/2016/1451-93721600023D.pdf |
| Summary: | The present study evaluated the recycling of crude glycerol as source of
catalyst for biodiesel production. For that purpose, two sets of experiments
were conducted. In the first set (A), biodiesel was synthesized by
conventional methanolysis of sunflower oil using NaOH as catalyst at 65°C
during 1 h and varying catalyst concentration (0.4 - 1.2 wt.%) or methanol to
oil molar ratio (6:1-12:1). The second set (B) was performed by replicating
the conditions of set A and considering the use of crude glycerol as source
of catalyst. The evaluation of excess methanol and catalyst distribution in
the crude products was performed. For both sets of experiments, product yield
and quality (viscosity and purity) were determined. Methanol was
predominantly in the glycerol phase (54 - 68%), with negligible effect of
variation in catalyst concentration and higher percentages found when higher
methanol to oil molar ratios were used, due to a higher polarity of this
phase. In most cases, catalyst was predominantly in the crude glycerol (53
wt.% in average) and no clear relation was found between catalyst
distribution and the different reaction conditions studied. The results from
set A showed a clear influence of catalyst concentration in biodiesel
conversion and a minor effect of methanol to oil molar ratio. The best
conditions were 6:1 methanol to oil molar ratio and 0.6 wt.% of catalyst
leading to a product yield of 95.1 wt.%, a purity of 99.3% and a viscosity of
4.59 mm2s-1. The second set of experiments showed different trends and
variability compared to the first one and the results indicated that catalyst
might be altered during glycerol storage. It was found an effect of methanol
to oil molar ratio in reaction conversion with the highest purity (96.9 wt.%)
being obtained when the highest molar ratio was used (12:1) possibly due to
the reduced mass transfer limitations. Overall, the results clearly show the
potential of using crude glycerol as source of catalyst, avoiding the use of
new catalyst and allowing a more sustainable biodiesel production. |
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| ISSN: | 1451-9372 2217-7434 |