Enhanced tar removal in syngas cleaning through integrated steam catalytic tar reforming and adsorption using biochar

Steam catalytic tar reforming (SCTR) using biochar is a popular technique for tar removal in syngas cleaning. However, its efficacy drops while treating syngas at low temperatures (< 750 degrees C) typically encountered in flu-idized or downdraft gasifiers. This work proposes integrating an adsorption section post reforming, that operates at a relatively lower temperature (220 degrees C) to additionally remove the light tar components using biochar. The integrated approach was assessed for the removal of mallee-wood generated tar using mallee-wood biochar as catalyst and adsorbent. Tar yield estimates revealed overall removal by-80 %, with reforming contributing-40 % and adsorption-60 % of the residual tar. Elaborate tar analysis based on UV-spectroscopy proved substantial removal of light tar compounds in the two-step process. Biochar structural analysis based on Raman spectroscopy revealed a growing predominance of higher aromatics in adsorbent during biochar-volatile in-teractions, due to adsorption of both heavy and light tar compounds. The evolution trends were validated by correlating the specific reactivity of utilized biochar samples based on thermogravimetric analysis. Biochar morphological analysis through BET analysis showed a steep drop in surface area from 101.40 to 0.043 m(2)/g, implying pore surface coverage by tar compounds which were also evident from FESEM images.

Automated summary

The integration of adsorption treatment in steam catalytic tar reforming using biochar significantly improves the removal of tar components, especially at low temperatures. The two-step process shows substantial removal of light tar compounds, with reforming contributing 40% and adsorption contributing 60% to the overall tar removal.