(48c) An Investigation on Short Residence Time Macro Algae Hydro Thermal Liquefaction in a Batch Reactor

AIChE annual meeting, November 2016 San Francisco

An investigation
on short residence time macro algae hydro thermal liquefaction in a batch
reactor

Arash Izadpanah
^a, Niccol˜ Le Brun ^a, Klaus Hellgardt^a

^a Department of Chemical
Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ,
United Kingdom

Bio
crude oil production from macro algae may become a key technology to tackle
tomorrowÕs renewable fuels challenge. In order to seed this technology it is
important to identify and evaluate the right process pathways to convert macro
algae to biofuels. In conventional algal biofuels processing, drying of the
algae is a costly procedure, which could be bypassed by using Hydrothermal Liquefaction
(HTL) technology with substantial advantages. For an efficient implementation
of a continuous HTL process, the effect of process variables on the conversion and
selectivity towards liquid biofuels needs to be understood. This is often a
challenge because the timescale of the HTL process is of the order of minutes
and it is difficult to be captured properly by ordinary methods. In this study
we employed a molten salt bath to facilitate rapid heat transfer to the batch
reactor and thus study HTL for precisely controlled residence times between 1
and 25 min. Under experimental conditions the conversion of macro algae to bio
crude oil was found to be complete within 15 min reaching a maximum and then
decreasing slightly (23% maximum yield after 11 min at 390 ¡C).
Using different analytical techniques including CHNS-O, GC-MS, Simulated Distillation
and Size Exclusion chromatography the bio crude from macro algae is characterized
and compared with North Sea crude oil.

Keywords: Macro
algae, Hydrothermal liquefaction, Conversion rate, Filtration, Centrifugation

Figure
1:Graphical summery of the
experiment

Figure
2: Bio crude oil yield as a
function of residence time at 250 , 320 , 390 .