Brazil has a long history in the development of ethanol for use as a liquid fuel for vehicles. They have developed one of most efficient and economical systems for producing ethanol in the world. Brazil provides an example that many other countries would like to emulate. Using ethanol as a vehicle fuel has significant potential air quality impacts. This paper will review the available air quality and vehicle emissions data in Brazil, specifically focusing on vehicle related pollutants that may be impacted by the use of large quantities of ethanol in the fuel. The atmospheric concentrations of acetaldehyde (CH3CHO) and ethanol in Brazil are much higher than those in other areas of the world, while the concentrations of the single ring aromatic compounds and small carboxylic acids are more typical of observations elsewhere. Acetaldehyde and ethanol increase in vehicle emissions and nitrogen oxides (NOx) may increase when ethanol fuels are used. Both CH3CHO and NOx are very important contributors to photochemical air pollution and ozone (O3) formation. There are very significant O3 air quality problems in Brazil, most studied in the larger cities of Sao Paulo and Rio de Janeiro. These are issues that must be evaluated for other areas of the world that are considering the use of high ethanol content vehicle fuels.

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Ethanol fuel use in Brazil: air quality impacts

Biodegradable and non-biodegradable fraction of municipal solid waste for multifaceted applications through a closed loop integrated refinery platform: Paving a path towards circular economy.

The role of ethanol as a fuel additive was investigated in a fuel-rich, non-sooting (C/O = 0.77) flat premixed propene–oxygen–argon flame at 50 mbar (5 kPa). Mole fractions of stable and radical species were derived using two different in situ molecular beam mass spectrometry (MBMS) set-ups, one located in Bielefeld using electron impact ionization (EI), and the other at the Advanced Light Source (ALS) at Berkeley using vacuum UV photoionization (VUV-PI) with synchrotron radiation. A rich propene flame, previously studied in detail experimentally and with flame model calculations, was chosen as the base flame. Addition of ethanol is believed to reduce the concentrations of benzene and small aromatic compounds, while augmenting the formation of other regulated air toxics such as aldehydes. To study the chemical pathways responsible for these effects, quantitative concentrations of about 35 species were determined from both experiments. This is also the first time that a detailed comparison of quantitative species concentrations from these independent MBMS set-ups is available. Effects of ethanol addition on the species pool are discussed with special attention on benzene precursor chemistry and aldehyde formation.

The influence of ethanol addition on premixed fuel-rich propene–oxygen–argon flames

Cold start emissions of an ethanol-fuelled engine with heated intake air and fuel

Computational study of intake temperature effects on mixture formation, combustion and unregulated emissions of a DISI methanol engine during cold start

This work describes the improvements on exhaust emissions and cold start obtained through utilization of a new type of cold-start auxiliary system for ethanol-fueled engines. Lower amounts of the gasoline used to help cold start and of ethanol injected during cold start and warm-up were used via introduction of a fuel injector in the new cold-start auxiliary system. The redesigned system allowed for faster and uniform cold start, in comparison to the conventional system, of around 31.1%. Reductions of raw hydrocarbon and carbon monoxide emissions in the cold stage of the FTP-75-based emissions test cycle were about 8.6 and 17.2%, respectively, while oxides of nitrogen and aldehyde emissions remained unchanged.

Jos Ricardo Sodré

Papers

Reducing exhaust emissions in ethanol-fueled engines during cold start