PROMOTION OF CO_2 HYDROGENATION IN FIXED BED RECYCLE REACTORS

摘要

One of the promising technologies for the utilization of CO_2 is the selective synthesis of valuable chemicals by means of catalytic hydrogenation. A catalytic fixed bed recycle reactor and series reactors have been proposed to increase the level of reaction conversion in conducting the hydrogenation of CO_2. The hydrogenation of CO_2 was carried out over Fe-K based catalyst. The conversion of carbon dioxide (X_(CO2)) increased with increasing reaction temperature and residence time (τ_(mod)) in the fixed bed single reactor. In series reactors, X_(CO2) increased up to the level of 68.5% (T=300℃, P=1.0MPa, H_2/CO_2=3 and SV=1.0Nl/g_(cat)hr) in comparison with the level of 40.8% in the fixed bed single reactor at the same conditions. Also, X_(CO2) increased with increasing recycle ratio (R) and it had maximum values with increasing total space velocity (SV_T) around 4-5Nl/g_(cat)hr in the recycle reactor. For the olefin rich production, maximum X_(CO2) was the level of 75% in the recycle reactor, however paraffin selectivity was increased when the X_(CO2) was above 80%. From the results of experiments, the recycle reactor as an alternative reactor was beneficial to increase X_(CO2) for the hydrogenation of CO_2 instead of the fixed bed single reactor.