Rosângela da Silva

Preliminary characterization of anhydrous ethanol used in Brazil as automotive fuel

This work reports preliminary studies on the characterisation of anhydrous ethanol (AEA) used as an automotive fuel mixed with gasoline in Porto Alegre (South Brazil). Pre-concentration of the impurities contained in 1000 ml of AEA was carried on through solid-phase extraction using XAD4 resin. The main compounds in the extract were identified by means of spectral data from the library of the equipment. The concentrate was then fractionated using a preparative liquid chromatographic column filled with activated silica gel and the elution procedure was carried out with, n-hexane, n-hexane-benzene (1:1, v/v) and dichloromethane. Prior to analysis by GC-MS, each fraction was reduced to 1 ml with a gentle stream of nitrogen. Saturated linear hydrocarbons and aromatic hydrocarbons eluted in the first fraction and oxygenated compounds such as aldehydes. ketones and alcohols, eluted in the second one. were the main compounds detected in the sample.

Desenvolvimento de um equipamento para avaliação do efeito do etanol na pressão de vapor e entalpia de vaporização em gasolinas automotivas

The quality of the gasoline utilized for fueling internal combustion engines with spark ignition is directly affected by the gasolines properties. Thus, the fuels properties must be in perfect equilibrium to allow the engine to perform optimally, not only insofar as fuel consumption is concerned, but also in order to reduce the emission of pollutants. Vapor pressure and vaporization enthalpy are important properties of a gasoline determining the fuels behavior under different operating conditions in internal combustion engines. The study reported here involved the development of a device to determine the vapor pressure and the vaporization enthalpy of formulations containing volumes of 5, 15 and 25% of ethanol in four base gasolines (G1, G2, G3 and G4). The chemical composition of these gasolines was determined using a gas chromatographer equipped with a flame ionization detector (FID).

Biodiesel Glycerides from the Soybean Ethylic Route Incomplete Conversion on the Diesel Engines Combustion Process

An evaluation was made to determine the effect of the glycerides presence resulting from the incomplete conversion of soybean biodiesel produced via alkaline catalysis and ethylic route on engine performance, and emissions in formulations containing 10 and 20% (m/m) of biodiesel used as additives in base diesel with low sulfur content and cetane ratings of 45 and 50. By way of comparison, similar formulations were used with soybean biodiesel methyl route with low concentration of glycerides. Tests on a diesel cycle engine with a mechanical fuel injection system indicated that the presence of glycerides decreases the volatility of biodiesel and increase the cetane number of fuels. The higher the cetane number, the higher the particulate matter emissions and the lower the unburned hydrocarbon emissions. Formulations with cetane number 50 showed higher emissions of particulate matter. The presence of glycerides in biodiesel reduces the fuel’s vapor pressure, thereby increasing the cetane number and emissions of particulate matter and lower emissions of unburned hydrocarbons. The specific consumption of fuels formulated with biodiesel increases due to its lower enthalpy of combustion and to the presence of glycerides in fuels formulated with soybean biodiesel produced via the ethanol route.

Bio-Oil Production by Thermal Cracking in the Presence of Hydrogen

This paper describes the bio-oil production process of a mixture of agricultural wastes: discarded soybean frying oil, coffee and sawdust, by pyrolysis and thermal cracking in the presence of hydrogen. The fractions obtained in the pyrolysis and/or cracking processes were divided into a light fraction and a heavy one. All the fractions were analyzed by comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC×GC/ TOFMS). The characteristics of the fractions obtained in resulting from the cracking process in the presence of hydrogen were have characteristics similar to those of petroleum-based naphtha, while the fractions obtained by from the pyrolysis contained process produced significant quantities of compounds such as furanmethanol, hexanol, and benzofuran, whose commercial value is high.

Rendimento térmico e emissões de contaminantes atmosféricos de gasolinas formuladas com etanol, MTBE e TAEE

The specific consumption and carbon monoxide (CO) and nitrogen oxide (NO) emissions from gasolines formulated with ethanol, methyl tert-butyl ether (MTBE) and tert-amyl ethyl ether (TAEE) were evaluated in the rich, stoichiometric and lean-burn regions during the operation of an Otto-cycle engine. The use of ethanol as an additive presented high specific consumption, while gasoline formulated with TAEE showed low specific consumption with the engine operating under lean-burn conditions. The ethers evaluated here presented a low percentage of CO in the rich-burn region when compared with ethanol.