Two proposals by researchers in the Texas A&M University College of Engineering received grants from the U.S. Department of Energy‘s (DOE) National Energy Technology Laboratory (NETL) University Coalition for Fossil Energy Research (UCFER) program.
UCFER is part of a six-year, $20 million project awarded by NETL. The goals of the project are to identify, select, execute, review and disseminate knowledge from research that will improve the efficiency of production and use of fossil energy resources while minimizing the environmental impacts and reducing greenhouse gas emissions.
Dr. Eric Petersen (principal investigator-PI), Nelson-Jackson Professor; and Dr. Waruna Kulatilaka (co-PI), associate professor; both in the Department of Mechanical Engineering, lead the project “Validation of CFD Models for Turbulent, Supercritical CO2 Combustion.” Dr. Jaime Grunlan (co-PI), Linda & Ralph Schmidt ’68 Professor in the mechanical engineering department; and Dr. Benjamin Wilhite (co-PI), associate professor in the Department of Chemical Engineering, lead the project “Layer-by-Layer Functional Thin Film Coatings for Enhanced Light Gas Separations.”
Petersen and Kulatilaka’s project combines state-of-the-art facilities in their laboratory with the computational fluid dynamics (CFD) expertise at DOE’s NETL. CFD is the use of applied mathematics, physics and computational software to visualize how a gas or liquid flows. The team will provide data to help validate the turbulent, reacting flow CFD model(s) at NETL. The overall approach is for the numerical simulations to directly model the experimental setup and results, hence validating the code at conditions that are relevant to supercritical-CO2 (SCO2) power cycles. Such a model could then be used with greater confidence when applied to modeling the complex SCO2 burners at extreme conditions such as at 300 bar, 700°C, and high levels of CO2 since few high-pressure data such as flame speeds, highly resolved images and flame zones at supercritical conditions currently exist in the literature.
A new experimental setup at the laboratory for studying turbulent flames in a controlled, high-pressure setting will be used that has the capability of producing turbulence at frequencies and length scales of interest to power generation applications.
“With the PLIF (planar laser induced fluorescence) diagnostic, we will be able to measure the spatial distribution of target molecules in the turbulent, reacting flow fields,” Petersen said. “The burst-mode laser system will also help us make sure measurements with much smaller time differences between each measurement, allowing for better temporal resolution of the phenomena.”
Their setup is also one of the very few vessels in the world that can be operated at elevated pressures up to 20 bar (approximately the pressure felt under 660 feet of water) while also having windows to view the application and development of advanced diagnostics. The optical imaging diagnostics will be based on established PLIF techniques (used for velocity, concentration, temperature and pressure measurements); cutting-edge, ultrahigh repetition rate, ‘burst-mode’ laser technology; and ultra-high-speed imaging. Such techniques have been rarely been used in spherical-flame experiments, so the proposed tests are new and innovative.
“The potential impact is on improving the design tools of the advanced combustion systems, leading to higher performance/efficiency engines,” Petersen said.
Thin Film Coatings for Enhanced Light Gas Separations
With their project, Grunlan and Wilhite say low cost, low-energy separation of light gases remains a critical challenge to creating a sustainable energy and liquid fuels foundation operable from coal, natural gas or biomass/biogas. For these resources to be converted to a combination of clean energy they must first separate out the impurities. To solve this problem, they have developed a completely new “game-changing” gas separation membrane coating that will make the process of extracting impurities easier and less expensive. They use a simple polymer-based film to remove the impurities, and their polymer membrane could perform as well as expensive materials such as mixed matrix membranes and zeolites.
The membrane that Grunlan and Wilhite have developed is a layer-by-layer polymer coating that is comprised of alternating individual layers of common, low-cost polyelectrolytes. The coating can be made by dipping or spraying, making it easy to apply to existing gas separation systems. These films separate molecules based on size, the smaller ones such as hydrogen pass through, while larger ones such as carbon dioxide and nitrogen are slowed down. And the more membranes it goes through, the purer it becomes, therefore allowing for more uses.
“The term ‘light gases’ usually refers to hydrogen and helium (i.e., low molecular weight and small atomic size),” Grunlan said. “Liquid hydrogen is a fuel and liquid helium is an important coolant for a number of applications. It is much colder than liquid nitrogen. For example, the Nuclear Magnetic Resonance tools used by chemists have magnets that need to be cooled by liquid helium.”
“By taking an off-the-shelf, low-cost membrane module and treating with our coatings, we hope to enable breakthroughs in gas separations that may be readily utilized by commercial industry,” Wilhite adds.”
UCFER will engage in both fundamental and applied research for clean and low-carbon energy based on fossil resources. Outreach and technology transfer to industry will be important components of the coalition. With the aim of reducing environmental impacts and minimizing carbon dioxide emission, the coalition will explore both research in coal and in natural gas and oil including carbon dioxide capture, storage and utilization.
Research in gas and oil will also include unconventional resources such as shale gas and environmental impacts, natural gas infrastructure — leak detection and smart sensors, deep water technology, methane hydrates and enhanced recovery.
Led by Penn State University, the founding members of the UCFER coalition team include the Massachusetts Institute of Technology, Princeton University, Texas A&M, University of Kentucky, University of Southern California, University of Tulsa, University of Wyoming and Virginia Tech University. Proposals for UCFER are directed through the Texas A&M Energy Institute, which helps to assemble teams, performs final checks on the proposals, serves on the governing board of the coalition, and provides steering advice for the direction of future proposal calls.