C.J. Philippopoulos

Regulated and unregulated emissions from an internal combustion engine operating on ethanol-containing fuels

In the present work, the effect of ethanol addition to gasoline on regulated and unregulated emissions is studied. A 4-cylinder OPEL 1.6 L internal combustion engine equipped with a hydraulic brake dynamometer was used in all the experiments. For exhaust emissions treatment a typical three-way catalyst was used. Among the various compounds detected in exhaust emissions, the following ones were monitored at engine and catalyst outlet: methane, hexane, ethylene, acetaldehyde, acetone, benzene, 1,3-butadiene, toluene, acetic acid and ethanol. Addition of ethanol in the fuel up to 10% w/w had as a result an increase in the Reid vapour pressure of the fuel, which indicates indirectly increased evaporative emissions, while carbon monoxide tailpipe emissions were decreased. For ethanol-containing fuels, acetaldehyde emissions were appreciably increased (up to 100%), especially for fuel containing 3% w/w ethanol. In contrast, aromatics emissions were decreased by ethanol addition to gasoline. Methane and ethanol were the most resistant compounds to oxidation while ethylene was the most degradable compound over the catalyst. Ethylene, methane and acetaldehyde were the main compounds present at engine exhaust while methane, acetaldehyde and ethanol were the main compounds in tailpipe emissions for ethanol fuels after the catalyst operation.

The Effect of Adding Oxygenated Compounds to Gasoline on Automotive Exhaust Emissions

In the present work, the effect of adding ethanol or methyl tertiary butyl ether (MTBE) to gasoline on the regulated and unregulated emissions from an internal combustion engine with a typical three-way catalyst was studied. The addition of ethanol to fuel (10% w/w) increased both the research octane number and the Reid vapor pressure of the fuel, whereas adding 11% w/w MTBE caused an increase only in the research octane number of the fuel. When the fuel contained MTBE, less hydrocarbons, carbon monoxide, and acetaldehyde were emitted in the tailpipe. The increased emissions of acetaldehyde and ethanol were the main disadvantages of using ethanol.

Acetaldehyde Yield and Reaction Products in the Catalytic Destruction of Gaseous Ethanol

The catalytic destruction of ethanol (0.5% v/v) over a typical three-way catalyst (Pt/Rh/Ce) and two base catalysts (1% CuO and 10% CuO on γ-Al2O3) was studied in a continuous flow reactor, under atmospheric pressure. The effect of the temperature (100--500 °C) and of the oxygen concentration (0--10% v/v) on the operation of the tested catalysts and on the product profiles is presented. The formation of acetaldehyde during the catalytic destruction of ethanol, the main concern of ethanol addition to fuels, was extremely dependent on the oxygen concentration. It is noteworthy that more acetaldehyde was produced during the oxidation of ethanol in oxygen deficit conditions than during its decomposition in the absence of oxygen. Copper addition on γ-Al2O3 enhanced acetaldehyde formation, while less acetaldehyde amounts were produced over the noble metal catalyst.

Photo-assisted Oxidation of Chlorophenols in Aqueous Solutions Using Hydrogen Peroxide and Titanium Dioxide

Abstract In the present work, the efficiency of phenol and chlorophenol degradation under irradiation using hydrogen peroxide as oxidant and titanium dioxide powder as photo-catalyst was investigated. In the absence of titanium oxide, increased concentrations of hydrogen peroxide resulted in higher conversions. Generally, phenol was the most readily oxidized compound, whereas in excess of hydrogen peroxide, the more chlorine atoms were present in the ring, the less degradable the chlorophenol was, in terms of initial rate of oxidation. In the case of 4-chlorophenol, the catalytic photo-oxidation efficiency with hydrogen peroxide and titanium oxide was dependent on the catalyst concentration exhibiting a maximum at 0.025–0.05 g L−1 titanium oxide. The combined use of titanium oxide and hydrogen peroxide resulted in higher degree of oxidation compared to results obtained when using hydrogen peroxide. Finally, the presence of Fe(III) proved to be beneficial for the photo-catalytic oxidation only in the presence of hydrogen peroxide.

Speciated Hydrocarbon and Carbon Monoxide Emissions from an Internal Combustion Engine Operating on Methyl Tertiary Butyl Ether-Containing Fuels

ABSTRACT In the present work, engine and tailpipe (after a three-way catalytic converter) emissions from an internal combustion engine operating on two oxygenated blend fuels [containing 2 and 11% weight/weight (w/w) methyl tertiary butyl ether (MTBE)] and on a nonoxygenated base fuel were characterized. The engine (OPEL 1.6 L) was operated under various conditions, in the range of 0-20 HP. Total unburned hydrocarbons, carbon monoxide, methane, hexane, ethylene, acetaldehyde, acetone, 2-propanol, benzene, toluene, 1,3-butadiene, acetic acid, and MTBE were measured at each engine operating condition. As concerns the total HC emissions, the use of MTBE was beneficial from 1.90 to 3.81 HP, which were by far the most polluting conditions. Moreover, CO emissions in tailpipe exhaust were decreased in the whole operation range with increasing MTBE in the fuel. The greatest advantage of MTBE addition to gasoline was the decrease in ethylene, acetaldehyde, benzene, toluene, and acetic acid emissions in engine exhaust, especially when MTBE content in the fuel was increased to 11% w/w. In tailpipe exhaust, the catalyst operation diminished the observed differences. Ethylene, methane,and acetaldehyde were the main compounds present in exhaust gases. Ethylene was easily oxidized over the catalyst,while acetaldehyde and methane were quite resistant to oxidation.