Experiment 11 - Biodiesel Processing.docx

1. Gas Chromatography-Mass Spectrometry (GC-MS) is an analytical instrumental technique that evaluates the chemical composition of a sample solution. The sample is vaporised in the GC column and injected into a gas mobile phase that carries it through a stationary phase. The components in the mixture are separated into traces of pure chemicals. In the MS, the mass spectrum of each component is identified by comparison with the mass spectra in the library, and the statistical probability is quantified. https://www.gmu.edu/depts/SRIF/tutorial/gcd/gc-ms2.htm 2. GC-MS is used to analyse levels of glycerine, esters, and residual methanol in biodiesel. http://www.biodieselmagazine.com/articles/1803/an-overview-of-biodiesel-test-methods/ 3. The samples injected into the GC-MS are diluted to decrease the solvent strength, to prevent the column from overload, to prevent saturating the detector, and ensure the output signal will be within the detector range. https://www.agilent.com/cs/library/primers/Public/5991-3326EN_SPHB.pdf pg 15 4. A 5. The melting point obtained from the DSC can be approximated as the pour point of the biodiesel. Melting point is the temperature at which a solid substance transitions from a solid to a liquid phase. It is equivalent to the freezing point, which is the reverse transition, from a liquid to a solid phase. The Pour Point is the temperature at which the liquid ceases to pour due to the precipitation of waxes. Thus, it can be approximated to the freezing point, which corresponds to the melting point. Or cloud point? http://www.glossary.oilfield.slb.com/Terms/p/pour_point.aspx http://www.omicsonline.org/biodiesel-from-household-restaurant-waste-cooking-oil-wco2157-7048.1000112.pdf 6. The cloud point is temperature at which the formation of wax crystals starts to occur. The accumulation of crystallised wax forms a cloudy appearance in the fuel mixture. http://www.glossary.oilfield.slb.com/Terms/c/cloud_point.aspx 7.