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 11^th ‘ 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.