The Synthesis of Clean Fuels by F-T Reaction from CO_2 Rich Biosyngas

摘要

This paper presents the results of Fischer-Tropsch (F-T) reaction in a fixed bed reaction system with CO_2 rich biosyngas to produce clean fuels which contain no sulfur, nitrogen and aromatics. Generally CO_2 is eliminated to get pure synthesis gas for the F-T reaction, but in this work, the authors did not separate CO_2 which is the most effective global warming gas and investigated the role of CO_2 in the reactions. In this study we targeted following points (ⅰ) how can we let not only CO but also CO_2 react, (ⅱ) how to suppress the water gas shift reaction, (ⅲ) how to treat the effluent gas after reaction, and (ⅳ) how to sustain the catalyst activity. To investigate such phenomena, we carried out the reactions over Fe-Cu based catalyst with various potassium content. In the reaction we used mainly a standard gas which is composed of CO:CO_2:H_2 = 2:1:4 vol.%. We found the best composition of catalyst and gas and optimal conditions to satisfy above targets. Furthermore we elucidated the causes of catalyst deactivation and thus proposed a two step reaction system to let more CO_2 react.