Panagiotis Xyradakis

Performance and Emission Characteristics of Spark Ignition Engine Fuelled with Ethanol and Methanol Gasoline Blended Fuels

Depletion of fossil fuels and environmental pollution has led researchers to anticipate the need to develop bio-fuels. Alcohols are an important category of bio-fuels. Methanol can be produced from coal, biomass or even natural gas with acceptable energy cost. Also, gasification of biomass can lead to methanol, mixed alcohols, and Fischer–Tropsch liquids (Chum and Overend, 2001). Ethanol is produced from sugars (particularly sugar cane) and starch by fermentation. The biomass industry can produce additional ethanol by fermenting some agricultural by-products (Prasad et al., 2007). Lignocellulosic biomass is a potential source for ethanol that is not directly linked to food production (Freudenberger, 2009). Shapouri et al. (1995) showed that the net energy value of corn ethanol has become positive in recent years due to technological advances in ethanol conversion and increased efficiency in farm production. Corn ethanol is energy efficient, as indicated by an energy ratio of 1.24, that is, for every Btu dedicated to producing ethanol, there is a 24-percent energy gain. Goldemberg et al. (2004) demonstrated, through the Brazilian experience with ethanol, that economy of scale and technological advances lead to increased competitiveness of this renewable alternative, reducing the gap with conventional fossil fuels. Consequently alcohols are particularly attractive as alternative fuels because they are a renewable biobased resource and oxygenated, thereby providing the potential to reduce particulate emissions in spark ignition engines. Kim and Dale (2004) estimated that the potential for ethanol production is equivalent to about 32% of the total gasoline consumption worldwide, when used in E85 (85% ethanol in gasoline) for a midsize passenger vehicle. Such a substitution immediately addresses the issue of reducing our use of non-renewable resources (fossil fuels) and the attendant impacts on climate change, especially carbon dioxide and the resulting greenhouse effect (von Blottnitz and Curran, 2007). The conversion of biomass to bio-fuel has some ecological drawbacks. It is well known that conversion of biomass requires additional energy inputs, most often provided in some form of fossil fuel. Also, agricultural production of biomass is relatively land intensive, and there

Comparison and analysis of the emissions of a small non-road spark-ignition engine operating under different alcohol–gasoline blended fuels

In this experimental study we focused our interest on comparing the effect of lower and higher molecular mass alcohol–gasoline-blended fuels on the regulated emissions emitted by a small non-road spark-ignition engine. Twenty-one test fuels were used in this experimental study that included gasoline as a reference as well as low and high molecular mass alcohol–gasoline blends containing 5%, 10%, 20% and 40% v/v. In exhaust gases that originated from alcohol gasoline test fuels, low CO/HC and high CO2/NOx emissions were observed as the total percentage of alcohol in the blend increased. Methanol–gasoline blends seemed to achieve good combustion efficiency, but the engine will require a catalytic converter against high NOx emissions. Butanol–gasoline blends in several cases gave lower emissions in comparison with the ethanol and propanol–gasoline blends. Finally, the pentanol–gasoline blends showed exactly the same emission patterns as those of neat gasoline.

Panicum virgatum L. Could Be an Alternative Environmental Friendly Feedstock for Energy Production

The investigation of alternative energy sources environmentally friendly is necessary, due to the decrease of fossil fuel reserves, the increased world population needs and the increased CO2 emissions. During the past two decades, researchers started to investigate the case of producing energy through crop production. Switchgrass is a perennial crop of low input requirements and high biomass production, which could produce high amounts of energy per hectare equivalent to oil. A three years field experiment was conducted in case to examine the effects of four nitrogen fertilization and two irrigation levels, in two different soils, at two different growing stages (vegetative stage and seed mature) on dry biomass yield, calorific value and ash content of switchgrass Alamo variety. It was found that higher dry yield (27-30 t ha) reached on the aquic soil while on the xeric remained at lower levels (14-15 t ha). In the case of the average calorific value it was observed a slight increase (from 17 to 17.3 MJ/kg) according only to crop maturation, while in the case of the average ash content crop maturation had the opposite effect (5.4 and 4.5%). Therefore, it is really important to refer that switchgrass cultivation is able to produce 466 GJ ha and 1.2 t ha ashes which can be used for fertilization and its introduction in future land use systems for an environmentally friendly energy production should be seriously taken into consideration.

Dynamic behaviour of an in-pipe sensor-based platform for soil water monitoring

Sensor-based technologies for pipeline soil water monitoring.Kinematics equations for the robotic platform were derived.Experimental vibration analysis for structural identification of an in-pipe platform. In this study, the dynamic behaviour of a sensor-based platform that travels through an underground pipeline network is investigated. The platform consists of a soil water sensor, placed on two articulated wheeled bases. In order to improve the maneuverability of the platform within the curved sections of the pipeline, an extension rod between one of the wheeled bases and the soil water sensor was added. Firstly, the behaviour of the platform in a curved section is demonstrated using mathematical modeling and numerical simulation. According to simulation results, the extension rod improves the turning radius (Rc=0.26m) of the platform significantly. On the other hand, it reduces the clearance (g=0.002m) between the soil water sensor and the inner sidewall of the curved pipe, affecting at the same time the tractive forces. Next, the vibration effect of the electromechanical devices on the sensor-based platform at low and high speed operation is investigated. The vibration magnitude for the case of high speed operation is almost identical to that for low speed operation, because it is mainly determined by the amplitude of the strongest mode. The platform modal behaviour depends only on the constructional details and is irrelevant to speed and type of excitation.