Otimização da síntese de biodiesel a partir do óleo de algodão (Gossypium hirsutum L.)

Abstract

Biodiesel is a fuel from renewable sources, such as vegetable oils and animal fat. Among the main lipid sources are cotton, which is considered the third source with potential biodiesel production in Brazil. The objective of this work was to optimize the production process of cotton biodiesel using five independent variables: reaction time, catalyst content, alcohol / oil ratio, reaction agitation speed and reaction temperature. A saturated PlackettBurman type planning was used to select the variables with the greatest effects, from which reaction time, alcohol / oil ratio and temperature were chosen. With the selection of variables, a complete factorial design 23 was used, with a completely randomized design, with 5 replications at the central point. However, the equation used to describe the process, through the analysis of variance analysis, however, the planning presented a lack of adjustment. Afterwards, a central rotational composite (DCCR) design was used, consisting of a factorial 23, with 5 repetitions at the central point and 6 axial points, totaling 19 experiments. For the mass yield process, at the 95% confidence level with R2 = 98.97%, the highest yield was obtained when the facto rs alcohol / oil ratio of 9: 1, temperature of 30oC and reaction time of 48 minutes, 93.38%. Through the scheduling of the equation, obtained by the DCCR, planning established as optimum experimental the following conditions: reaction time 13.85 minutes, t emperature 17.98oC and alcohol / oil ratio 6.66: 1. Under these experimental conditions the maximum yield calculated was 94.89% and the observed 94.52%.