Colloquium: Prof. Matthew Cavalli
Dr. Matthew Cavalli, P.E.,
Associate Professor and
Dept. of Mechanical Engineering,
University of North Dakota
Friday Jan 16, 2015, 4:00–5:00pm, 211 Witmer Hall. Refreshments at 3:30pm.
Materials Issues in Coal Gasification and Hydrogen Production
In 2013, 39% of the electricity generation in the US came from coal. Integrated Gasification Combined Cycle power generation offers the potential for more efficient electricity production with fewer emissions compared to combustion of pulverized coal. In the gasification process, synthesis gas (syngas) is produced which consists primarily of hydrogen, carbon dioxide and carbon monoxide along with trace impurities depending on the fuel being gasified. Both the high hydrogen content and the trace impurities represent challenges for the materials used in constructing the powerplant. Hydrogen embrittlement can reduce ductility of metallic parts, leading to premature fracture and plant down-time and potential safety hazards. Trace elements in the syngas may pass through the combustion process and deposit on the turbine, creating novel corrosion conditions that can also lead to premature failure and excessive maintenance costs. In this presentation, past work to characterize trace contaminants in syngas generated in gasifiers at the Energy and Environmental Research Center (EERC) from various coal feedstocks will be reviewed. A concurrent project to reduce spallation of corrosion-resistant thermal barrier coatings (TBCs) of turbine blades and combustor components will also be discussed. Finally, recent work to characterize the potential effects of hydrogen embrittlement in stainless steel alloys will be presented. Results indicate that embrittlement may be present under conditions where it is not usually thought to be a problem.