[Che-student-staff-list] Vinod Kumar Venkatakrishnan Dissertation Defense, Wednesday, September 10th, at 8:00 a.m. in FRNY 3062B

[Maus, Amy M]

This e-mail is to announce that Vinod Kumar Venkatakrishnan will be defending his dissertation, Lab-Scale Fast-Hydropyrolysis and Vapor-Phase Catalytic Hydrodeoxygenation for Producing Liquid Fuel Range Hydrocarbons from Intact Biomass , on Friday, July 11th ' at 1:00PM in FRNY 3062B. The dissertation is being co-advised by Doctors Agrawal, Delgass, and Ribeiro, and the abstract is below. All are welcome to attend.


Abstract:
Liquid transportation fuels are primarily produced from petroleum-based non-renewable
carbon sources. Sustainably available lignocellulosic biomass, as a renewable form of
atmospheric carbon, could be utilized to produce hydrocarbon-based fuels with high energy
density. One of the process options for this conversion is the H2Bioil process, where biomass is
rapidly heated in a hydrogen environment to produce fast-hydropyrolysis vapors that are
catalytically upgraded in downstream hydrodeoxygenation (HDO) to produce hydrocarbons.
This process has been modeled to have high carbon and energy efficiencies of ~70% and ~75%,
respectively.
This dissertation presents the results of a lab-scale experimental proof-of-concept for the
H2Bioil process for converting intact biomass to liquid fuel range hydrocarbons. Based on
various prototype designs for high pressure (up to 68 bar) fast-pyrolysis in an inert environment,
a cyclone-type fast-hydropyrolysis reactor system along with downstream vapor-phase catalytic
HDO reactor was designed and constructed. A liquid chromatography-mass spectrometry based
analytical technique was developed for quantitative compositional analysis of the cellulose
pyrolysis liquid products. Levoglucosan and its isomers, cellobiosan, water and light oxygenates
like formic acid, glycolaldehyde and hydroxyacetone are the major products of cellulose fastpyrolysis.
Increasing pyrolysis temperature in the range of 480 ºC to 580 ºC was found to
increase the formation of light oxygenates, due to the increase in thermal cracking, and to
decrease carbon recovery in the liquid. Comparison of cellulose fast-pyrolysis and fasthydropyrolysis
experiments showed that H2 does not play an important role in deoxygenation
even up to 50 bar H2 partial pressures in the absence of a downstream HDO catalyst.
Candidate catalyst screening and previous work from our research group revealed that
adding an oxophillic promoter, such as Mo, along with the hydrogenation function of Pt, could
increase C-O bond scission. Hence, a 5wt%Pt-2.5wt%Mo catalyst supported on multi-walled
carbon nanotubes (MWCNT) was tested for HDO of fast-hydropyrolysis vapors from cellulose,
as a model biomass feedstock, and poplar, as a real biomass feedstock. The total C1-C8+
hydrocarbon yield (as % carbon of feed) with cellulose was ~73%, the liquid fuel range (C4+)
hydrocarbon yield was ~55%, with a major fraction as C6 hydrocarbons from the HDO of
levoglucosan and its isomers. The total C1-C8+ hydrocarbon yield (as % carbon of feed) with
poplar was ~54%, and the liquid fuel range hydrocarbon yield (C4+) was ~32%, with a major
fraction as C8+ hydrocarbons from the HDO of lignin fragments. Increasing the HDO
temperature from 300 ºC to 350 ºC increased the C-C bond scission and led to higher yields of
CO and lower yields of C4+ hydrocarbons. Independent control of fast-hydropyrolysis and HDO
temperatures in the H2Bioil process helps in improving the overall C4+ hydrocarbon yields. For
improving the overall carbon efficiency from the experimental proof-of-concept of the H2Bioil
process, synergistic process integrations, involving gasification, combustion and reforming, have
been suggested within the group for utilizing carbon from CO, char and C1-C3 hydrocarbons to
increase the yield of liquid fuel range (C4+) hydrocarbons.
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