Increased energy independence and the aim to transform to the
low carbon intensive society motivate the increased use of locally
available and carbon neutral primary materials, which in practice
mostly address renewables. In parallel, albeit the net positive carbon
emissions, the ever-growing issue of waste is supporting the
energy recovery from wastes with high energy content [1]. In both
cases, combustion in externally fired Rankine cycle is still a prevailing
technology even though the electrical efficiency of such systems
is usually lower than 25% [2]. To obtain electric efficiencies
in excess of 30%, internal combustion principle is much more suitable.
Here, two options are available on the low end of the power
scale – reciprocating engines and gas turbines. The first ones are
attractive due to their availability, low price and generally higher
efficiency. In addition, biomass-to-liquid fuels [3], alcohols [4]
and advanced 2nd generation biofuels [5] were also utilized several
times in reciprocating engines. Gas turbines are particularly
suitable for fuels with less favorable physical and/or chemical
properties due to their continuous combustion principle and thus
inherent ease of fuel injection and mixture preparation.
Published works on internally fired micro gas turbines generally
cover straight vegetable oils – in [6], numerical simulations of
spray pattern, supported by experimental evaluation of power output
and emissions were done with 100% vegetable oil, while in [7]
several blends of vegetable oil and diesel fuel were tested up to
100% vegetable oil and in [8] 10% and 20% blends of different oils
with JET A1 fuel were experimentally evaluated with regards to
performance, gaseous and particulate emissions. Some studies
were also analyzing the possibility to use waste trap grease [9].
Several studies were focused also on methyl esters but they can
be at present time considered as an industrial standard, since
recent EN590:2013 standard already allows up to 7% content of
fatty acid methyl ester. To utilize the full potential of robust burning
characteristics of microturbines, fuels with even less favorable
properties or additional advanced biofuels could be exploited. Such
systems are currently limited only to medium power range turbine