We present an innovative reaction set-up and process for biodiesel manufacturing by
heterogeneous catalysis. This process has two key advantages over the state-of-the-art
process: it enables a variable reaction time and easy catalyst switching/replacement.
The process principle presented here is generic for liquid-phase reactions requiring
long residence times, where conventional fixed-bed column reactors offer little flexibility.
This is especially important when one switches between feedstocks or when the catalyst
activity declines over time. Biodiesel manufacturing is a highly relevant example,
because the reactor performance depends on the feedstock nature and composition. The
concept is demonstrated in a scaled-down continuous laboratory reactor, keeping a
similar reaction time and comparable heat and mass transfer to a large-scale process
by optimising the reactor dimensions, fluid velocity and catalyst pellet size. We
then provide the design of the large-scale process, which consists of serpentine-type
plug flow reactors assembled as vertical tubes filled with catalysts. The reactor
productivity can increase significantly by reducing the catalyst pellet size. A switching
system allows connecting/bypassing the tubes and easy catalyst replacement. The reactor
can be employed in a two-stage reaction technology, or in a one-stage reaction combined
with membrane separation. Production capacity can be scaled-up simply by adding parallel
modules. The versatility and ease of application make this catalytic process concept
suitable for low-cost mobile biodiesel production plants.