Effects of residue and antioxidant on thermo-optical properties of biodiesel

Abstract

Thermal lens (TL) spectrometry was applied to soybean biodiesel samples, in order to assess the behavior of their thermo-optical properties during the preparation before and after the washing process. The study was based on the thermal diffusivity parameter, which is highly sensitive and is related to the chemical composition of the sample. The results showed a difference of approximately 20% between the initial (unwashed) and the final (washed) steps of biodiesel production. This behavior indicates that the residue of the biodiesel production influences the thermal diffusivity value. Consequently, TL spectrometry can be a useful methodology for certifying the quality of biodiesel during production.

Characterization of Biodiesel by Unconventional Methods: Photothermal Techniques

“…The results of thermal conductivity can be determined using the relation  = k/c. The values obtained are in agreement with the results from literature (Castro et al 2005, Lima et al 2009). Several factors, such as presence air, light, heat (high temperature), light traces of metal, antioxidants, peroxides as well as the nature of the storage containers can trigger oxidative processes, thus will be altered the quality of biodiesel (Knothe et al, 2005).…”

“…This variation may be related to oxidative processes because the thermal diffusivity measurements between the TL and PPE were carried out to set at the intervals of 15 months, approximately. Similar results were observed by Lima et al 2009 andCastro et al, (2005) which observed a reduction in the thermal diffusivities in oxidated samples.…”

“…Using thermal lens, it was possible to measure the thermal diffusivity and the temperature coefficient of refraction index of biodiesel samples obtained from distinct precursor oils, using both ethanol and methanol for the transesterification processes (Castro et al, 2005). Furthermore, it was applied to soybean biodiesel samples in order to evaluate the influence of residues and antioxidants on its thermo-optical properties (Lima et al, 2009). The photopyroelectric was used to the complete thermal characterization of biodiesel, meaning the determination of the thermal diffusivity, effusivity, conductivity and the heat capacity per unit volume ).…”

Reabilitação estética anterior com sistema IPS e.max: relato de caso

“…A indicação das coroas unitárias totalmente cerâmicas tem como objetivo reabilitar principalmente a estética, autoestima e bem estar além de promover a saúde periodontal, periapical e melhorar a função mastigatória da paciente. Estudos recentes sugerem que a confecção de coroas com sistemas cerâmicos totalmente livres de metal são uma excelente alternativa restauradora, com potencial estético superior ao das coroas metalocerâmicas 2,6,17,19,20 . Vários estudos mostram que a prótese de cerâmica pura é indicada em áreas onde se faz necessária cobertura total e estética máxima, no entanto não é indicada para reabilitação em dentes posteriores devido à maior tensão mastigatória 4,5,8 .…”

Thermal lens spectroscopy for the differentiation of biodiesel-diesel blends

“…Thermal lens (TL) spectroscopy has been extensively used to characterize different materials, including solutions such as oil and biodiesel. [13][14][15][16] The TL procedure centers on the observation of the heat generated in the sample when it absorbs energy from a laser beam with a Gaussian intensity profile. The absorbed energy induces a temperature variation in the sample that is larger in the center than at the border of the beam, following the spatial distribution of the laser beam intensity.…”