Comparing the Performance of Compact Heat Exchange Reactor to CSTR for Fischer Tropsch Synthesis

A commercial Fischer Tropsch catalyst was studied in two Compact Heat Exchange Reactors (CHER) with different channel sizes, and in a continuous stir tank reactor (CSTR).  The  CHERs were constructed by Chart Energy and Chemicals with one reactor having a 5mm channels and the other having a 6mm channels, while maintaining the same catalyst volumeThe catalyst was crushed and sieved retaining particles ranging in size from 75-125µm. Testing was performed at the University of Kentucky Center for Applied Energy Research in Lexington, KY.  The CO conversion, selectivity and hydrocarbon productivity were measured for each reactor over a wide range of operating conditions, as a function of temperature, pressure, H2:CO feed ratio, and flow rate.  Both reactor types showed excellent temperature control, but the performances varied at different operating conditions.  The larger channel CHER had a higher conversion than the 5mm channel, potentially due to slightly higher reactor bed temperature.  The two CHERs approached and even exceeded the productivity of the CSTR for liquid hydrocarbons per gram of catalyst.  At higher flow rates the methane selectivity increases at a lower rate for either of the CHERs than for the CSTR.