Fast pyrolysis of biomass is one of the most recent renewable energy processes to have been introduced. It offers the advantages of a liquid product, bio-oil that can be readily stored and transported. Bio-oil is a renewable liquid fuel and can also be used for production of chemicals. Fast pyrolysis has now achieved a commercial success for production of chemicals and is being actively developed for producing liquid fuels. Bio-oils have been successfully tested in engines, turbines, and boilers, and have been upgraded to high-quality hydrocarbon fuels, although at a presently unacceptable energetic and financial cost. The paper critically reviews scientific and technical developments in applications of bio-oil to date and concludes with some suggestions for research and strategic developments.

Overview of Applications of Biomass Fast Pyrolysis Oil

This study presents one scenario for a 100% renewable energy system in Europe by the year 2050. The transition from a business-as-usual situation in 2050, to a 100% renewable energy Europe is analysed in a series of steps. Each step reflects one major technological change. For each step, the impact is presented in terms of energy (primary energy supply), environment (carbon dioxide emissions), and economy (total annual socio-economic cost). The steps are ordered in terms of their scientific and political certainty as follows: decommissioning nuclear power, implementing a large amount of heat savings, converting the private car fleet to electricity, providing heat in rural areas with heat pumps, providing heat in urban areas with district heating, converting fuel in heavy-duty vehicles to a renewable electrofuel, and replacing natural gas with methane. The results indicate that by using the Smart Energy System approach, a 100% renewable energy system in Europe is technically possible without consuming an unsustainable amount of bioenergy. This is due to the additional flexibility that is created by connecting the electricity, heating, cooling, and transport sectors together, which enables an intermittent renewable penetration of over 80% in the electricity sector. The cost of the Smart Energy Europe scenario is approximately 10–15% higher than a business-as-usual scenario, but since the final scenario is based on local investments instead of imported fuels, it will create approximately 10 million additional direct jobs within the EU.

Smart Energy Europe: The technical and economic impact of one potential 100% renewable energy scenario for the European Union

Effects of butanol–diesel fuel blends on the performance and emissions of a high-speed DI diesel engine

The development of kerosene-like drop-in alternative aircraft fuels is currently receiving increased attention. Using a range payload approach the need for drop in fuels is justified. The alternative fuels available can be categorised into two groups; depending on whether the product increases supply security of supply or provides a reduced environmental footprint. This paper uncovers this relationship through a review of commercially available process technologies (Transesterfication, Fischer–Tropsch (FT) and hydroprocessing (HRJ)) to produce alternative fuels. The lifecycle assessments available are reviewed to identify what are actually clean fuels or have the potential to be one. A summary of the recent alternative fuel flight test campaigns is given and there results evaluated along with ground based results. A review of combustion characteristics available for the alternative fuels including ignition characteristics are presented to demonstrate the effect the distillation curve has on combustion and how too narrow a distribution of components in the fuel could generate problems with high altitude relight. The effect alternative fuels have on gaseous emissions regulated by the International Civil Aviation Organisation (ICAO) Committee on Aviation Environmental Protection (CAEP) is discussed and shown to be engine hardware dependant. Experimental data, from an Auxiliary Power Unit (APU) engine, are provided showing how, although the Gas to Liquid (GtL) and Coal to Liquid (CtL) FT fuels may not reduce GHG emissions, even with Carbon Capture and Sequestration (CCS), the local air quality around airports will benefit through reduced particulate emissions. Finally the prospects for future fuel development are discussed.

Aviation gas turbine alternative fuels: A review

The increasing energy demand, surging oil prices, depleting oil reserves and environmental pollution problems associated with the use of fossil fuels have sparked renewed interest to find out clean alternative fuels. Alcohols such as methanol, ethanol and butanol are competitive alternative fuels due to their liquid nature, high oxygen contents, high octane number and their production from renewable biomass. In this review, the fuel properties of these alcohols are compared with conventional gasoline and diesel fuel. The comparison of fuel properties represents that butanol has the potential to overcome the problems associated with the use of methanol and ethanol. Progresses of their production from different sources are also introduced. Further, several techniques such as alcohol–diesel fuel blends and alcohol–diesel fuel emulsions are discussed, especially for lower alcohols, in order to use them in diesel engines. The effects of diesel–alcohol blends on the combustion, performance and emissions of diesel engines are also analyzed. It is examined that blending of alcohols, along with some CN improver, to diesel fuels can reduce diesel engine emissions without adverse impacts on the performance of diesel engines. These studies also reveal that butanol is a better alternative for diesel fuel due to its superior fuel properties and miscibility with diesel fuel than those of methanol and ethanol. Finally, some critical conclusions and future research directions are highlighted.

Advances in diesel–alcohol blends and their effects on the performance and emissions of diesel engines

: A series of experiments on steam condensation have been made in a Laval nozzle over a variety of starting conditions such that the onset of condensation occurs in the range -40 to 40 C. The homogeneous nucleation and growth of the new phase is documented with both static pressure and laser light scattering. Since even at onset the majority of the condensed phase is due to droplet growth the nucleation and growth are coupled and the availability of two measured quantities is helpful in comparing a particular combination of nucleation rate and growth law. For detailed calculations on one of the experiments there is excellent agreement with both measurements throughout the condensation zone and a theoretical calculation using the classical nucleation rate expression due to Volmer and a droplet growth law due to Gyarmathy.

On the Growth of Steam Droplets Formed in a Laval Nozzle Using both Static Pressure and Light Scattering Measurements

Performances et emissions polluantes de l'ethanol et de melanges ethanol-carburant diesel dans des moteurs diesel a injection directe et prechambre de combustion

Performance and Emissions of Ethanol and Ethanol-Diesel Blends in Direct-Injected and Pre-Chamber Diesel Engines

In 1999, as the only inland petroleum refinery in South Africa was reaching capacity, Sasol gained approval of a semi-synthetic jet fuel (SSJF) for civil aviation to augment production and meet the growing demand for jet fuel at the airport in Johannesburg. Prior to this, all jet fuel had to be refined from petroleum sources. SSJF consists of up to 50% of an iso-paraffinic kerosene produced from coal using Fischer-Tropsch processes. The production of SSJF remains vulnerable to the production capacity of conventional jet fuel, however. To ensure supply, Sasol has proposed producing a fully synthetic jet fuel (FSJF) using synthetic kerosene streams that contain aromatics and satisfy all the property requirements of international specifications for jet fuel. Being fully synthetic, it was necessary to demonstrate that the fuel is “fit-for-purpose” as jet fuel, i.e., behaves like conventional jet fuel in all aspects of storage and handling as well as air worthiness and flight safety. Four sample blends were developed covering the practical range of production. Extensive tests on chemistry and physical properties and characteristics demonstrated that Sasol FSJF will be typical of conventional jet fuel. As a final demonstration, the engine manufacturers requested a series of engine and combustor tests to evaluate combustion characteristics, emissions, engine durability, and performance. The performance of the synthetic test fuel was typical of conventional jet fuel. This paper identifies the tests and presents the results demonstrating that Sasol fully synthetic jet fuel is fit-for-purpose as jet fuel for civilian aviation. Sasol FSJF is the first fully synthetic jet fuel approved for unrestricted use.Copyright © 2008 by Sasol Technology (Pty) Ltd

Properties, Characteristics, and Combustion Performance of Sasol Fully Synthetic Jet Fuel

Vaporization of Individual Fuel Drops on a Heated Surface: A Study of Fuel-Wall Interactions within Direct-Injected Gasoline (DIG) Engines

The dependence of relative soot concentration on flame temperature and fuel composition was measured in a small-scale research combustor. The purpose was to gain a better understanding of the correlation of soot formation with H/C ratio. First, the effect of flame temperature on soot concentration was determined by varying the burner inlet temperature. Then, 10 fuels with H/C ratios in the range of 1.98 to 1.55 were used in an experiment 10 determine the effects of both flame temperature and fuel composition on relative soot concentration. Flame temperatures were calculated and measured optically by the Kurlbaum technique. Flame opacity measurements were used to determine relative soot concentration. The results showed that while soot concentration increased significantly as flame temperature increased, the ncrease in soot with fuels of lower H/C ratio was much stronger than could be attributed to associated increases in the tlame temperature.

Clifford A. Moses

Papers

On the Growth of Steam Droplets Formed in a Laval Nozzle Using both Static Pressure and Light Scattering Measurements

Performance and Emissions of Ethanol and Ethanol-Diesel Blends in Direct-Injected and Pre-Chamber Diesel Engines

Properties, Characteristics, and Combustion Performance of Sasol Fully Synthetic Jet Fuel

Vaporization of Individual Fuel Drops on a Heated Surface: A Study of Fuel-Wall Interactions within Direct-Injected Gasoline (DIG) Engines

Effects of Flame Temperature and Fuel Composition on Soot Formation in Gas Turbine Combustors