Residence time distribution of a continuous pilot plant horizontal pretreatment reactor at various conditions

Residence time is a critical parameter that strongly affects the product profile and overall yield achieved from thermochemical pretreatment of lignocellulosic biomass during production of liquid transportation fuels.  Reactors at pilot and commercial scale typically operate in continuous mode with imperfect plug flow and a distribution of residence times instead of a desired finite time.  The residence time distribution (RTD) quantifies reactor performance and provides a metric to compare changes in reactor design and operating parameters.  A new measurement technique to measure RTD in pretreatment reactors was developed and validated.  Sodium chloride and electrical conductivity instrumentation provide an inexpensive and rapid online measurement method to assess the residence time characteristics at a variety of operating conditions.  This method was implemented on a 600 kg/day pilot scale horizontal pretreatment reactor to determine how various operating parameters affect RTD.  Important information regarding optimum reactor conditions and reactor design have become available through this study and will be disseminated.