Abstract
The talk covers the optimal design and operation of zero and partial emission cycles for power generation and water desalination, focussing is on oxycombustion with carbon capture. Oxycombustion is a thermodynamically attractive concept that seeks to mitigate the penalties associated with CO2 capture from power plants. The main disadvantage is the need to separate oxygen from atmospheric air. This can be achieved using conventional cryogenic air separation or novel membranes. In either case, careful integration of the air separation, power generation and CO2 treatment is required to achieve high conversion efficiencies. Moreover, in order to obtain meaningful prediction of efficiencies detailed modeling of all processes involved is mandated, but this is often ignored in the literature.
In the first part of the talk, a semi-commercial pressurized oxy-coal combustion is considered. Multi-variable optimization is performed involving high-fidelity modeling of the power plant units. Continuous and discrete variables are varied simultaneously to maximize thermal efficiency while satisfying techno-economic constraints. The optimization leads to significant efficiency improvement and more moderate operating conditions (lower pressure) compared to prior studies based on single-variable sensitivity analysis.
In the second part, integrated oxygen ion transport membranes (ITMs) are considered for oxygen separation for the oxycombustion of natural gas. Oxygen separation in an ITM system consists of many distinct physical processes, ranging from complex electrochemical and thermochemical reactions, to conventional heat and mass transfer. The dependence of ITM performance on power cycle operating conditions and system integration schemes must be captured in order to conduct meaningful process flow and optimization studies. An axially distributed, quasi two-dimensional model is presented. Several power cycles from the literature are considered, along with new proposals, including separation in a reactive environment. The detailed modeling demonstrates that several literature claims are overly optimistic since they neglect irreversibilities and operational constraints. Moreover, the model is used to examine the feasibility of novel concepts to overcome some of the challenges associated with the ITM. Finally, the merit of partial CO2 emission concepts, as well as the integration of ITM with desalination and concentrated solar power is discussed.
Biography
Alexander Mitsos is Professor of Process Systems Engineering at RWTH Aachen. He obtained his un-dergraduate degree at Karlsruhe University in 1999 and his PhD from MIT in 2006. He was a junior group leader in AICES, RWTH Aachen in 2008, and a Rockwell International Assistant professor in the department of Mechanical Engineering at MIT from 2009-2012, before becoming a Professor of Process Systems Engineering at RWTH Aachen. His research focus is broadly on energy and chemical systems and optimization algorithms. He serves on the editorial board of the Journal of Global Optimization.