Recently, biomass utilization is regarded as a promising waste-to-energy technology, especially pyrolysis and gasification. However, to implement in advanced applications, such as internal combustion engines, the cleanliness of synthesis gas should be highly taken into consideration because tar contained in synthesis gas causes blocking and fouling in downstream components. Therefore, tar removal by physical methods, which are highly effective and economical, have been developed. In this study, enhancement of the tar removal performance of vegetable oil scrubbing was investigated over a 10 h experimental period to increase both the tar removal efficiency and the useful life of vegetable oil. There were two methods investigated for regenerating deteriorated absorbent oil: filtration and centrifugal sedimentation. Results showed that only 48% of gravimetric tar was removed by non-regenerated oil, while the tar removal efficiencies of 78 and 83% were achieved by incorporating the filtration and centrifugal sedimentation, respectively. For light tar removal, the main advantage of the filtration method was to increase the phenol removal efficiency, while all naphthalene could be removed by the centrifugal sedimentation. Furthermore, the gravimetric tar removal efficiency of regenerated oil after each regeneration method was recovered to more than 90%, which was almost the same as that of new oil. Therefore, there is a possibility for using regenerated absorbent oil without changing the new absorbent oil frequently.