Geraldo Ferreira David

Effect of acid additives on sugarcane bagasse pyrolysis: Production of high yields of sugars.

The aim of this work was to improve sugarcane bagasse thermochemical conversion to pyrolytic sugars production, particularly to levoglucosan. The experiments were carried out evaluating the effect of acid washing with HNO3 (0.1wt.%) followed by H2SO4 addition (0.1, 0.2 and 0.3wt.%) at pyrolysis temperatures of 350, 400, 450, 500, 550 and 600°C was studied by Py-GC/MS. The experimental results showed that HNO3 washing, followed by H2SO4 concentration of 0.2wt.% at 350°C resulted in an increase in levoglucosan yield between 5 and 7 times the yield obtained when the raw bagasse was processed. Thus, these results are very attractive to improve pyrolytic sugars production in sugarcane bagasse by previously acid treatment to pyrolysis technology.

Trends in Biodiesel Production: Present Status and Future Directions

The use of renewable fuels, an alternative that reduces the generation of greenhouse gases, is one proposal to mitigate the effects that contribute to global warming. Brazil is the fourth largest producer of biodiesel in the world, and growth expectations of the productive capacities have generated huge technological and environmental challenges. In this context, this chapter discusses some of the relevant aspects of biodiesel production in Brazil, including sustainability of raw materials, conventional technology limitations, and further presents technological alternatives as strategies that will guide the future directions which can result in processes with greater environmental and economic returns.

Methyl Esters Production by Heterogeneous Catalyst Mixtures of CaO/Nb2O5 with Simulation of Analysis of Environmental Impacts

The conventional biodiesel process, although it reaches high conversion yields and productivity, faces problems related to the use of homogeneous catalysts. This work aims to study mixtures of calcium oxide (CaO) and niobium oxide (Nb2O5) as the heterogeneous catalyst. It was used a full 2 factorial design with four central points to analyze how the mass percentage of the oxides, the molar ratio of reactants, and the reaction temperature affect the conversion yield to methyl esters. The best conversion yield was found near to 89% using 1.8% of catalyst, a 1:36 oil to methanol ratio and at 77 °C as reaction temperature. Finally, it was performed a simplified simulation to compare the heterogeneous catalyst process with the conventional process, and an algorithm to compare the effects of the exit streams of each process would have on the environment. The simulations results display a better performance for the heterogeneous catalyst process studied.