KUTEM Seminar Series Prof. Dr. Ahmet Kerim AvcıAuthor: KOC UNIVERSITY TUPRAS ENERGY CENTER
Location: ENG 208
Speaker: Prof. Dr. Ahmet Kerim Avcı, Department of Chemical Engineering, Boğaziçi University
Title: Intensified Conversion of Conventional and Renewable Fuels for Energy Applications
Place: Eng 208
Hydrogen and syngas (CO+H2) are key feedstocks for many industrial processes such as Fischer-Tropsch or methanol syntheses and hydro-processing steps involved in refinery operations. Steam reforming (SR) and autothermal reforming (ATR) of hydrocarbons, mostly natural gas, are the primary routes to produce syngas and hydrogen. Tubular reactors packed with Ni-based catalysts are used for running SR at ~800oC, for which heat is supplied either by a direct-firing furnace or by heat exchange with a hot stream. Although SR is well known and widely used, its efficiency is limited by transport resistances. Distribution of external heat to the catalyst bed may not be uniform, and local fluctuations in temperature can affect product distribution. In contrast with SR, ATR couples exothermic oxidation and endothermic reforming of the fuel in the same volume. It is run at temperatures in excess of 900oC, which supplied by oxidation to produce CO-rich syngas. Although careful balance of two reactions can run syngas production, the reactor geometry, a high-pressure vessel involving packed bed of particulate catalysts, is inherently not ideal for preventing hot-spot formation and for effective heat transfer along the catalyst bed.
Microchannel reaction technology has come out to offer substantial improvements in the conventional reforming techniques. Microchannel reactors consisting of parallel, identical channels with characteristic dimensions less than 1 mm, permit better control of the process under laminar flow conditions. Since the transport distance is reduced, heat can be delivered uniformly and rapidly to the catalyst, which is mostly in the form of a thin, porous layer coated on the inner channel walls. Miniature dimensions also allow for high surface area-to-volume ratios and enhanced heat transfer coefficients that are 50–100 times higher than those inconventional reactors. These factors lead to notable volumetric intensification, significant improvements in process efficiency, and allow on-site production in remote locations. Due to the efficient utilization of the catalyst, only a thin layer of it is sufficient to drive the reactions to almost completion with negligible pressure drop.
In this talk, an overview of catalytic microchannel reactors in the context of hydrogen and syngas production from renewable and conventional fuels will be provided. The talk will also include description of computational and experimental tools developed to explore the behavior of microchannel units. Potential use of microchannel reactors in applications such as glycerol valorization, water-gas shift, high-temperature Fischer-Tropsch (FT) synthesis and oxidative coupling of methane (OCM) will be described in the context of short case studies.
Dr. Ahmet Kerim Avci has received BS, MS and PhD degrees in Chemical Engineering from Bogazici University in 1996, 1997 and 2003, respectively. He worked as an R&D manager in Procter & Gamble Brussels Innovation Center, Belgium, where he directed strategic projects on packaging initiatives for Western Europe. As of September 2005 he joined to Bogazici University as a full time faculty at the Assistant Professor level. He promoted to Associate Professor and Professor levels in 2010 and 2015, respectively. Dr. Avci’s research interests are focused on experimental and computer-based investigation of novel catalytic hydrogen and synthesis gas production from conventional and renewable resources, synthesis gas conversion technologies, and intensification of catalytic reactors by microchannel technology. He is the leader of numerous research projects funded by governmental institutes and industry, is the author of more than 30 international journal publications, and is the co-editor of the book entitled “Multiphase Catalytic Reactors: Theory, Design, Manufacturing, and Applications”, that is published by Wiley in 2016. Dr. Avci is the holder of several awards such as Distinguished Young Scientist Fellowship (Turkish Academy of Sciences, 2009), Excellence in Research Award (Bogazici University Foundation, 2010), Eser Tümen Outstanding Achievement Award for Young Scientists (Feyzi Akkaya Research Fund for Scientific Activities,2011) and Research Incentive Award (METU Prof. Mustafa N. Parlar Foundation,2011).