**3. Results and Discussion**

Treatments were designed to investigate tar reduction (removal) efficiencies of wood shavings filter (dry filter) with and without syngas cooling and bubbling systems. Accordingly, the tar contents were measured at the inlet and outlet of the cleaning systems for the three treatments: (i) wood shavings filter; (ii) wood shavings filter after a heat exchanger; and (iii) wood shavings filter after an oil bubbler. Pressure drop, an important indicator in determining the tar absorbed by filter medium, was measured across the wood shavings filter over time. Similarly, because the temperature of syngas plays a vital role in condensation and deposition of tar, temperatures were recorded at the inlet and outlet of the cleaning systems. The gasifier was purposefully operated at low temperatures, which resulted in high syngas tar content to test the capabilities of the cleaning systems. The removal of tar can involve condensation or absorption process. In this experiment, the removal of tar by wood shavings involves condensation. Whereas, the removal of tar by oil is an absorption-based process because the solvent (oil) dissolves the tar products.
