Combustion Performance of Biodiesel and Diesel-Vegetable Oil Blends in a Simulated Gas Turbine Burner

Abstract

Recent increases in fuel costs, concerns for global warming, and limited supplies of fossil fuels have prompted wide spread research on renewable liquid biofuels produced domestically from agricultural feedstock. In this study, two types of biodiesels and vegetable oil (VO) are investigated as potential fuels for gas turbines to generate power. Biodiesels produced from VO and animal fat were considered in this study. The problems of high viscosity and poor volatility of VO (soybean oil) were addressed by using diesel-VO blends with up to 30% VO by volume. Gas chromatography/mass spectrometry, thermogravimetric analysis, and density, kinematic viscosity, surface tension, and water content measurements were used to characterize the fuel properties. The combustion performance of different fuels was compared experimentally in an atmospheric pressure burner with an air-assist injector and swirling primary air around it. For different fuels, the effect of the atomizing airflow rate on Sauter mean diameter was determined from a correlation for air-assist atomizers. Profiles of nitric oxides (NOx) and carbon monoxide (CO) emissions were obtained for different atomizing airflow rates, while the total airflow rate was kept constant. The results show that despite the compositional differences, the physical properties and emissions of the two biodiesel fuels are similar. Diesel-VO fuel blends resulted in slightly higher CO emissions compared with diesel, while the NOx emissions correlated well with the flame temperature. The results show that the CO and NOx emissions are determined mainly by fuel atomization and fuel/air mixing processes, and that the fuel composition effects are of secondary importance for fuels and operating conditions of the present study.

The impact of spray quality on the combustion of a viscous biofuel in a micro gas turbine

“…Firstly, the evaporation behavior as well as the combustion kinetics of vegetable oil and diesel fuel are similar. The differences in fuel composition will therefore have only minor effects, as was concluded by Panchasara et al [37] after experiments in an atmospheric pressure burner. This leaves the atomization quality as the main factor influencing the combustion of this biofuel, which is dominated by the viscosity in the tested fuel temperature range [30,31].…”

Spray and combustion characteristics of biodiesel: Non-reacting and reacting

“…There have been reports from several groups that applied biomass-derived alternative fuel using liquid swirl flame burners (Hashimoto et al, 2008;Panchasara et al, 2009) and industrial gas turbines (Moli ere et al, 2007;Liu et al, 2009). Hashimoto et al (2008 reported lower NO x emission for palm biodiesel compared to diesel under gas turbine operating conditions.…”

“…The interest of applying biodiesel in gas turbine largely stems from the merits of renewability, sulphur-free and potentially cleaner combustion. However, due to differences in quality of biodiesel depending on feedstock, rigorous testing have to be performed to characterise the spray, combustion and emission performance to ensure the suitability and reliability of biodiesel in gas turbine.There have been reports from several groups that applied biomass-derived alternative fuel using liquid swirl flame burners (Hashimoto et al, 2008;Panchasara et al, 2009) and industrial gas turbines (Moli ere et al, 2007;Liu et al, 2009). Hashimoto et al (2008 reported lower NO x emission for palm biodiesel compared to diesel under gas turbine operating conditions.…”

Spray flame structure of rapeseed biodiesel and Jet-A1 fuel

“…These prior studies considered overall emissions for biofuels relative to conventional practical fuels, without detailed characterisation of the swirl spray droplet transport and trajectories, flow fields and flame reaction zones [6,7]. Spray flames involve the complex interaction of air, fuel and chemistry that results in the simultaneous heat, mass and momentum transfer in addition to chemical reaction.…”