One-stage syngas-to-fuel in a micro-structured reactor: Investigation of integration pattern and operating conditions on the selectivity and productivity of liquid fuels

A one-stage syngas-to-fuel process was carried out by integrating Fischer-Tropsch synthesis (FTS) with hydrocracking (HC) in a micro-reactor to verify the feasibility of a related process simplification with a view to small-scale X-to-liquid (XtL) plants. Different approaches to the integration of the two process steps and the influence of the operating conditions were investigated targeting liquid fuel synthesis (C5-C20). It was proven that FTS plays the determining role in the integrated process and HC only exhibits a promoting function. Good performance was obtained in both sequential and mixed-bed systems. With an increase of temperature the liquid fuel selectivity reaches a plateau value of around 70% at 230-250 °C, depending on the integration pattern and syngas space velocity. H2/CO ratio and pressure only have limited influence on the fuel selectivity. FTS was enhanced in the mixed-bed configuration. Meanwhile, consistent hydrocarbon distribution was obtained for both integration patterns when reaching the plateau fuel selectivity. The catalyst stability in both configurations was analyzed, and a reasonable and comparable long-term stability was obtained.