Effect of Steam on the Tar Reforming during Circulating Fluidized Bed Char Gasification.

In this work, the real tar was introduced into the circulating fluidized bed gasifier by pre-mixing tar and char. The effect of steam on the tar reforming characteristics at both 850 and 900 °C was investigated by combining the analysis of the rate of tar conversion, the change of tar content, and char physical structure. The test results indicated that steam could effectively promote the tar conversion. Therefore, the content of tar in the final gas could be reached as low as 32 mg/Nm. It was found that the effect of steam on the different components of tar was in difference. Among the various components, polycyclic aromatic substances were more inclined to decompose. The results of BET confirmed that the distribution and structure of pore were obviously developed at the presence of steam, and the abundant pore structure further improved the catalytic performance of the char on the tar conversion in turn.