Avaliação do uso da cinza da casca de arroz como alternativa na purificação do biodiesel

Abstract

Biodiesel is a biofuel produced by converting triglycerides into alkyl esters. After synthesis, biodiesel must undergo purification step to remove residues of free glycerin, alcohol, water and catalyst. This work aimed to evaluate methods of purification of biodiesel from cottonseed oil (wet and dry), incorporating the use of rice husk ash as an alternative adsorbent to the studies. The viscosity, density, free glycerin content, acidity, iodine and saponification parameters were submitted to statistical analysis and compared with the limits established by ANP Resolution n° 45/2014. The results indicate that the Amberlite BD10DRY resin proved to be very efficient for purification, however it presented the characteristic of raising the acidity index of the biodiesel. The rice husk ashes proved to be efficient in reducing the analyzed parameters, mainly in the reduction of acidity, however, it was not effective for adapting to the content required by the ANP for free glycerin. It is important to note that despite the content remaining slightly above the required level, there was a reduction between 89.44 and 95.2% in relation to unpurified biodiesel. The results obtained with rice husk ash suggest that, with adaptations, they can be used as a pre-filter and/or post-filter in the biodiesel purification step. Complementary studies must be carried out to optimize the conditions to try to improve the percentage of glycerin reduction to meet the ANP specification.