Biomass tar is the
bottleneck of biomass gasification, which not
only is adverse to energy production but also brings severe environmental
issues. A scrubber with vegetable oil is considered as a low-cost
but efficient approach for tar removal, but the effects of oil’s
properties on different tar absorptions were rarely reported. In this
study, canola oil, palm oil, and pure oleic acid and linoleic acid,
which are the main compounds of vegetable oils, were employed for
absorptive removal of benzene, toluene, and phenol. The degree of
unsaturation, average molecular weight, and average chain length of
solvents were quantitatively characterized. A series of time and temperature-dependent
absorption experiments were conducted, and the relationship between
oils’ properties and absorption performances was built. Results
showed that pure oleic acid had the biggest absorption capacity for
benzene and toluene due to the mono-unsaturated structure. Increasing
the average molecular weight and chain length also enhanced tar absorption.
Moreover, Grey relative analysis was employed to investigate the influence
of each factor on tar absorption. The average molecular weight exerted
the most significant influence on tar absorption in the tested temperature
range whose comprehensive relevance coefficients reached the highest
at 0.9810, 0.7669, and 0.7739 for benzene, toluene, and phenol, respectively.
This study puts more attention on the nature of vegetable oils, and
we hope to provide useful information for modulating a better oil-based
scrubber medium and further enhancing tar absorptive removal.