Three-dimensional simulation analysis of the effect of hydrous ethanol and exhaust gas recirculation on gasoline direct injection engine combustion and emissions

To analyze the influence of hydrous ethanol on the performance of the direct injection engine, the three-dimensional simulation is carried out by using CONVERGE software coupled with the combustion mechanism of hydrous ethanol gasoline and the soot model. The combustion and soot generation characteristics of a direct injection gasoline engine burning aqueous ethanol gasoline using exhaust gas recirculation (EGR) technology were investigated. It was found that the increase of the blending ratio of the hydrous ethanol can accelerate the flame propagation speed, shorten the combustion duration, and improve the combustion isovolume. The nucleation and growth of soot are jointly controlled by PAHs and the small molecular components such as C2H2. The oxygen content properties and high reactive OH of the aqueous ethanol-containing gasoline inhibit soot formation. Compared with pure gasoline, the carbon soot precursor mass was reduced by 60%, 54.5%, 73.3% and 52.4% for 20% anhydrous ethanol blended with gasoline, A1, A2, A3 and A4, respectively, and the carbon soot mass was reduced by 63.6% and the carbon soot volume density was reduced by 40%. The introduction of EGR exhaust reduces the burning rate and leads to an increase in the production of Carbon monoxide, hydrocarbon, and soot. However, the combination of EGR with aqueous ethanol gasoline can significantly improve the engine combustion environment, significantly reducing soot and PAHs concentrations. The impact of EGR also includes the ability to reduce combustion chamber temperatures and reduce NOx emissions from aqueous ethanol gasoline by 75%.

Optimization of Esterification Reaction Conditions Through the Analysis of the Main Significant Variables

Biodiesel production from residual sources is gaining considerable attention nowadays. Consequently, many different studies with in-depth analysis concerning the influence of the transesterification reaction conditions are available in the literature. However, further evaluation of the esterification of fatty acids in the biodiesel industry is still needed. In this study, different parameters influencing the esterification reaction behavior using ethanol as the alcohol and lauric acid as the FFA are analyzed through factorial design and ANOVA methodologies to verify which ones are significant in the reaction. In total, four parameters were evaluated: temperature, catalyst concentration, ethanol/FFA ratio, and ethanol/water ratio. The temperature and ethanol/water ratio had a major influence on the reaction, as increasing these parameters greatly improved reaction conversion. It was also verified that using hydrous ethanol in the esterification reaction is possible in some conditions.

Analysis of Hydrous Ethanol Price Competitiveness after the Implementation of the Fossil Fuel Import Price Parity Policy in Brazil

Competition is a relevant element in any open economy. Public policies are necessary to induce economic efficiency and to create conditions to preserve or stimulate a competitive environment. This paper aims to assess the competitiveness of hydrous ethanol price in a period of political, social and economic crises, in 15 Brazilian state capitals between the years 2012 and 2019. We compared the ethanol–gasoline price ratio behavior in two different periods, before and after the import parity price policy implemented by Petrobras in 2016. Mann–Whitney and Levene’s tests, two non-parametric statistical methods, were applied to verify significant changes between these periods. The implementation of changes in Petrobras’ pricing policy from 2016 onwards caused a statistically significant increase in the ratio coefficient of variation in two-thirds of the distribution market and more than the half of analyzed retail markets. Second, overall, the cities that showed statistically significant changes in the median and coefficient of variation in the distribution market price ratio were followed by the retail market. Our findings suggest that government interventions in the fuel and byproduct final selling prices to distributors negatively impact competition between companies that are part of the fuel distribution and retail chain, also affecting the sale of biofuels in Brazil and discouraging the initiatives to use renewable fuels to reduce the emission of pollutants.