Bio
Extensive process and new product development experience including electronic grade silicon, CVD, SiC deposition, solar silicon, graphite, pyrolytic carbon. Organic and inorganic chemistry experience including silicone polymer synthesis, methylchlorosilane production and silane synthesis. Expertise in lithium-ion battery (LIB) silicon-anode and scale up of the anode active material process. Expertise in catalyst development for many areas of industry including petroleum, fuel synthesis, and chemical reactions. Well-connected in industries including energy storage, energy production, and renewable energies. Substantial experience in process modeling & CFD simulation leading to plant production increase. Experienced in all aspect of new product development, from fundamental theory, lab-scale testing, scale-up to commercialization. Deep understanding of chemical kinetics, thermodynamics phase equilibrium, mass and heat transfer, physical phenomena, and their applications. Works well with operational support and manufacturing engineering teams to help solve problems based on sound science and experimental discipline.
Professional Experience
Professional Experience
Senior Scientist
Oak Ridge National Laboratories (ORNL), Oak Ridge, TN
3/2021- Present
- Technical leader for the design and development for a continuous silicon carbide fiber line project from the Department of Energy.
- Led and developed melt spinning process technology for making SiC precursor filaments (20-micron diameter) for further conversion processing.
President and the Founder
Energy Solver LLC, Moses Lake, WA
Consulting on Si/C anode for Li-Ion battery scale-up and engineering design.
Scale-up Technology Leader
Nexeon Ltd., United Kingdom
- Lithium-ion battery scale-up for next generation batteries for EVs.
- Project management and tracking progress against milestones and deliverables.
- Designed production facilities and reactors to achieve project targets.
- Performed cost analysis (CAPEX/OPEX) for the project.
Silicon Scientist
REC Silicon
Solar and electronic grade silicon production, Moses Lake, WA
- Scaled-up electronic-grade silicon production to a pilot scale CVD reactor resulting in multi-million-dollar sale of the technology.
- Designed, developed, and scaled-up a breakthrough RF melting technology for consolidating granular silicon (US2015225246A1) and combined with Float Zoning crystal growth, delivered analytical tool for impurity analysis saving company $1Million expense annually.
- Improved process yields of the large-scale CVD process by developing fundamental understanding of the physics/chemistry of the deposition exploiting the combined power of lab-scale (DOE), process modeling (MathCad, Excel), and simulation (Barracuda, MFIX).
- Supported the manufacturing process increasing efficiency and product quality by developing all-in-one analysis tool.
- Supported sales by engineering solutions to customer-specific product quality issues.
- Evaluated projects based on financial analysis (NPV).
Research and Development Manager
Bay Carbon Inc., Bay City, MI
- Designed and built chemical vapor deposition (CVD) reactor for depositing silicon carbide (SiC) coating to expand customer base.
- Skilled in film characterization techniques & Hands-on experience with FTIR, DSC, TGA, GDMS, DC-ARC/OES, SEM/EDX, XRD, SIMS, ICP-MS, conductivity measurement, thickness measurement, and 3-D physical dimension measurements (CMM).
- Enabled timely solutions to customer requests by using sound engineering principles.
- Served as a consultant on graphite making principles, carbonization, and pyrolytic carbon processes.
Process Engineering Specialist
Dow Corning Corp., Midland, MI
- Developed nanometer-to-micrometer scale intimate contact carbon matrix to host silica particles and scaled up the process to the pilot scale.
- Formulated a curable resin polymer binder and applied to agglomerate carbon-based and silica-based materials.
- Led and facilitated commercial scale trials for smelting and upgrading of silicon to ensure that solar silicon product launches take place on time.
- Designed, constructed, and operated pilot scale silicon purification furnace to quickly screen potential raw materials to expedite commercialization.
Senior Process Engineer
Dow Corning Corp., Carrollton, KY
- Led the development of copper-based catalyst for conversion of silicon metal into chlorosilane gas products.
- Executed projects to increase yield for catalytic dimethyldichlorosilane synthesis reaction in the lab-scale by improving fundamental understanding.
- Experienced for the use of methlchlorosilanes and monosilanes in industrial applications.
- Led trials in the commercial scale to maximize productivity and selectivity by using design of experiments (DOE).
- Reduced expenses by $2 million as a member of “Cost Reduction Team” by optimizing catalyst schedule and silicon particle size distribution.
- Managed externally funded projects with various universities and government laboratories involving direct synthesis of methylchlorosilanes.
Colorado School of Mines
Post Doctorate Research Associate, Golden, CO
- Developed the most effective steam-reforming catalyst for making syngas (CO+ H2) gas from hydrocarbons.
Education
Education
Doctor of Philosophy in Chemical Engineering,
University of Colorado, Boulder, CO
Master of Science in Chemical Engineering and Petroleum Refining,
Colorado School of Mines, Golden, CO
Bachelor of Science in Chemical Engineering
(Summa cum Laude),
Technical University of Istanbul, Turkey
Trademarks and Patents
- Process for preparing electro-active materials for metal-ion batteries (US 10,508,335 B1, Dec.17, 2019), Sefa Yilmaz, Charles Mason, Richard Taylor, and David Bent, Nexeon Ltd, UK
- Silicon-Carbon composite materials and methods (WO 2021/048556A1), Charles Mason, Richard Taylor, Sefa Yilmaz, Kseniia Katok, Joshua Whittam, Limunga Silo Meoto, and Mauro Chiacchia, Nexeon Ltd, UK.
- Non-Contaminating Bonding Material for Segmented Silicon Carbide Liner in A Fluidized Bed Reactor (US 9,662,628 B2), Sefa Yilmaz, Matthew Miller, Mike Spangler, Barry Wemp, Stein Julsrud, REC Silicon, Moses Lake, WA
- Method and Apparatus for Consolidation of Granular Silicon and Measuring Non-Metals Content (US Patent 2015/0225246 A1), Sefa Yilmaz, Theodore F. Cizsek, Mathew Miller, Stein Julsrud, REC Silicon, Moses Lake, WA.
- Method for Annealing Granular Silicon with Agglomeration control, (WO 2018/140257 A1), Matthew Miller, Robert Geertsen, Johnston Justin, Stein Julsrud, Sefa Yilmaz
- System for Reducing Agglomeration During Annealing of Flowable, Finely Divided Solids, (WO 2018/140258 A1), Robert Geertsen, Matthew Miller, Johnston Justin, Stein Julsrud, Sefa Yilmaz
- Control of Silicon Oxide Off-Gas to Prevent Fouling of Granular Silicon Annealing System, (WO 2018/140259 A1), Robert Geertsen, Matthew Miller, Johnston Justin, Sefa Yilmaz, Stein Julsrud.
- Segmented Tubes used in Annealing of High Purity Silicon Granules, (WO 2018/140260 A1), Matthew Miller, Robert Geertsen, Stein Julsrud, Sefa Yilmaz, Raymond Desbordes.
- Method of Producing Metals and Alloys by Carbothermal Reduction of Metal Oxides, (WO 2009/020890 A1) Victor Black, Gary Burns, Robert Herbert, Sefa Yilmaz
- Method of Removing Impurities from Metallurgical Grade Silicon to produce Solar Grade Silicon (US Patent 2007/0202029 A1), Gary Burns, James Rabe, Sefa Yilmaz.
Other Publications
- Yilmaz S., Theodore M., Ozcan S., Silicon carbide fiber manufacturing: Cost and technology, Composites Part B 269 (2024) 111101.
- Zhao X., Karakaya C., Qian M., Zou R., Zhang W., Lu Z., Maiti D., Samanta A., Wan W., Liu X., Tiplea A., Li Y., Cui S., Wang C., Lei H., Bankston S., Yilmaz S., Chen J., Ozcan S., 3D printing synthesis of catalysts, Materials Today Sustainability xxx (2024) 100746.
- A Semi-Quantitative Comparison of Silane and TCS Based FBRs for Producing Granular Si as Solar Si Feedstock, Sefa Yilmaz, Tony Thompson, Stein Julsrud, and Matthew Miller, Silicon for the Chemical and Solar Industry XII, Trondheim, Norway, June 24 – 27, 2014
- Olakangil, J. F.; Rethwisch, D. G.; Yilmaz, S.; Kuivila, C. S., “Effect of promoters on the reaction kinetics of the direct process”, Silicon for Chemical Industry Conference, Tromso, Norway, 2000.
- Floquet, N., Yilmaz, S., and Falconer, J., “Interaction of Copper Catalysts and Si(100) for the Direct Synthesis of Methychlorosilanes”, J. Catal., 148, 348 (1994).
- Yilmaz, S., Floquet, N., Falconer, J., “Influence of Catalyst and Oxide Thickness During Dimethyldichlorosilane Formation on Si(100)”, Proceedings of Silicon for Chemical Industry II, Intl. Conf., 2nd, p.137-146 (1994), Tapir Forlag, Trondheim, Norway.
- Yilmaz, S., Floquet, N., Falconer, J., “The Effect of Oxide Thickness on the Rate and Selectivity of Methylchlorosilanes on Silicon Surfaces”, J. Catal., 159(1), 31 (1996).
- Falconer, J. and Yilmaz, S., “The Rochow Direct Synthesis on Single Crystal Silicon”, Proceedings of Silicon for Chemical Industry, p.99-109, Geiranger, Norway, 1992.