Performance evaluation of the methods used for the determination of sulphur content in fuels and biofuels

This paper presents the results of an experimental research study having as objective the
development of a routine method based on ion – chromatography technique, used for the
sulfur content determination in solid and liquid fuels.
The proposed procedure was applied on the determination of total sulfur in samples of coal,
fuel oil and biomass with different sulfur content ranging from 0.05 % to 0.6 %.
The methodology consists of the sample preparation by Eschka method based on igniting a
test portion of coal sample in intimate contact with Eschka mixture at 800C , or by combustion
of the fuel oil or biomass sample in a closed system containing oxygen (calorimeter bomb),
followed by the selective determinations of sulfur content using ion-chromatography and
gravimetric techniques.
When ion chromatography technique is used for sulfur content determination in coal and fuel
oil, the precision of values expressed as the relative standard deviations (% RSD, n=10), were
1.47 % and 0.61 %, which has been understood as being much lower than those obtained by
gravimetric standard methods, more precisely, 3.46 % for coals and 2.46 % for fuel oil.
For biomass with a sulfur content about 10 times less than in coals and fuel oil, best results
were obtained by ion – chromatography technique with the low limit of the measuring range
much smaller than the limit reached by applying the gravimetric technique.