Debasish Kuila is the Research Director/Professor of NSF-CREST Bioenergy Center and previous Chair of chemistry at NC A&T. He was an associate professor at Louisiana Tech and spent over 10 years at Hoechst Celanese and Great Lakes Chemical Corporations and Purdue University. He received his M.Sc. from IIT, Madras, Ph.D. from CUNY, NY, and did his postdoctoral work at The University of Michigan/LANL and Northwestern University. His research spans from materials/biomaterials, drug delivery, drug toxicity, cell biology, biosensors to catalysis. He has 12 US Patents/applications and >60 publications and has been invited as keynote and plenary speakers for international conferences.
Fuel production using Fischer-Tropsch (F-T) process from biomass, coal and natural gas has attracted tremendous attention in recent years. F-T synthesis, also known as gas-to-liquid (GTL) technology, converts unconsumed natural gases into hydrocarbons that are subsequently converted to fuels by hydrocracking for low cost production and easy transportation. The development of robust and stable catalysts and their supports for F-T synthesis is the major thrust of our research for CO2-rich syngas conversion (CO:H2) to higher alkanes using Si-micro-channel microreactor [1, 2].
Microreactors containing microchannels, termed as ‘Lab-on-a-chip’ devices, measuring a few centimeters in length and volume , provide high specific surface area in the range of 10,000-50,000 m2/m3 compared to the conventional reactors with ~100-1000 m2/m3 . The reaction parameters such as temperature, pressure, and flowrate can be varied easily since the small parallel flow paths in microreactors with high aspect ratios (channel height to width) strongly reduce the pressure drops. They can be scaled-up easily and the large surface-to-volume ratio of the microchannels inhibits gas-phase free-radical reactions and improve heat transfer for exothermic reactions. They are ideal for small-scale explosive reactions. The Si-microreactors, used in our studies, were fabricated by lithography followed by inductively coupled plasma (ICP) etching on silicon wafer, yielding 116 channels, each 1.3 cm long.
Recently, we demonstrated  a novel method, modified closed channel infiltration (mCCI) , to produce an uniform catalyst layer of ~10 µm for silica sol-gel coatings containing Ru, Fe and Co- catalysts. Highest CO conversion of 90% was obtained with Co/SiO2 at 250°C. In addition, Co/SiO2 catalyst showed highest deactivation resistance, followed by Fe/SiO2 and Ru/SiO2 in F-T synthesis. To investigate effect of support on catalysis, the Si-microchannels were also coated with titania sol-gel containing Ru, Co, Fe catalysts. Preliminary studies on catalytic performance, investigated in the temperature range of 150°C to 300°C, exhibited stability and reactivity in the order of 12%Ru-TiO2 >> 12%Fe-TiO2 > 12%Co-TiO2.
In this work, cobalt-based nanocatalysts with suitable support were used to perform FT process in silicon microreactor. During catalyst synthesis, we have intuitively harnessed the concept of mechano-chemistry whereby the planetary ball mill is utilized to make solid state alloy catalysts as well as homogeneous slurry from highly stable and reactive powder such as, MCM-41 supported catalysts. The slurries are subsequently mixed with polyvinyl alcohol (PVA) as binding agent to promote uniform coating in microreactor and adherence for F-T reactions. The synthesized catalysts were characterized by SEM, TEM, TPR and XRD techniques. The catalytic performance of different cobalt-based catalysts are currently being evaluated in silicon microreactor with H2/CO molar ratio of 2. For the ball milled mesoporous bimetallic catalysts in microreactor, 12%Ru12%Cu-MCM-41 catalyst showed 100% ethane selectivity at 250C and 12%Fe-SBA-15 showed 95% ethane and 4% methane selectivity at 350C. Ru-Co-MCM-41 catalyst exhibited selectivity of methane 76.6%, ethane 21%, propane 1.1% and butane 1.4% at 250C. The selectivity of methane, ethane, propane and butane with traces of oxygenates are currently being investigated for different cobalt-based catalysts.
Audience Take away:
• The audience will be exposed to the use of microchannel microreactors for catalysis.
• They can use “Lab-on- Chip” concept for catalysts development. In contrast to conventional F-T plants requiring minimum capacity of ~ 30,000 barrels/day (bpd) of liquid fuel, novel microreactor technology -based plants are economical even at 1,000 bpd of fuel
• F-T synthesis in a microreactor has great potential to produce environmentally friendly synthetic fuels.
• The other faculty can definitely expand their research and teaching. It can be extremely useful for explosive reactions in a small scale. It can certainly assist other researchers in a design problem.