masterThesis
Avaliação oxidativa do biodiesel de pinhão manso em diferentes processos de purificação
Fecha
2013-07-18Registro en:
CORDEIRO, Diego Oliveira. Avaliação oxidativa do biodiesel de pinhão manso em diferentes processos de purificação. 2013. 103 f. Dissertação (Mestrado em Físico-Química; Química) - Universidade Federal do Rio Grande do Norte, Natal, 2013.
Autor
Cordeiro, Diego Oliveira
Resumen
The objective of this study was to analyze the oxidative stability of biodiesel from jatropha
obtained from different purification processes, three wet processes with different drying (in a
vacuum oven, conventional oven and in anhydrous sodium sulfate) and dry (purification with
magnesium silicate adsorbent). Raw materials of different qualities (jatropha crop ancient and
recent crop) were used. The Jatropha oil was extracted by mechanical extraction and refined.
The Jatropha biodiesel was obtained by the transesterification reaction in ethyl route using
alkaline catalysis. The biodiesel samples were characterized by analysis of water content,
carbon residue, Absorption Spectroscopy in the Infrared Region and Thermogravimetry.
Thermogravimetric curves of purified PUsv* PUsq* and had higher initial decomposition
temperatures, indicating that the most stable, followed by samples PU* and PUSC*. Besides
the sample SP* is a smaller initial temperature, confirming the sample without purification to
be less thermally stable. The percentage mass loss of the purified samples showed conversion
of about 98.5%. The results of analyzes carbon residue and infrared suggested that
contamination by impurities is the main factor for decreased oxidative stability of biodiesel.
The oxidative stability was assessed from periodic monitoring, using the techniques of
Rancimat, peroxide index, acid value and Pressurized Differential Scanning Calorimetry.
Samples of biodiesel from jatropha which showed better oxidative stability were of the best
quality raw material and wet scrubbing: PUsq* with dry chemical, using anhydrous sodium
sulfate and PUsv* with vacuum drying, which had oxidative stability 6 hours in Rancimat
time 0 days, within the limits established by the Technical Regulation No. 4/2012 of the ANP,
without the addition of antioxidant, suggesting that these procedures the least influence on the
oxidative stability of biodiesel