A partnership between researchers at the University of Virginia and the University of Houston has continued to flourish, and expanded to another professor at the Worcester Polytechnic Institute, after the National Science Foundation chose their Emerging Frontiers in Research and Innovation (EFRI) proposal – the development of dynamically operated, smaller scale reactors that can process distributed feedstock – for a $2 million award.
Dr. Lars C. Grabow, Dan Luss Professor in the William A. Brookshire Department of Chemical and Biomolecular Engineering at the Cullen College of Engineering, is a co-PI on the project and will lead a team of researchers at the University of Houston. He identified Dr. Michael P. Harold and Dr. Praveen Bollini, also of the William A. Brookshire Department of Chemical and Biomolecular Engineering, as two colleagues that will be taking part in the research with him.
The principal investigator for the award is Dr. William Epling, the Department Chairman of Chemical Engineering at UVA. They are joined on the project by Dr. Andrew Teixeria, another co-PI and an Assistant Professor of Chemical Engineering at WPI.
Grabow said his work with Epling is a continuation of their research partnership.
“Dr. Epling has been a longtime collaborator of mine,” Grabow said. “He joined UH in 2011, at the same time I did, and left to join UVA as Department Chair about four years ago. While he was at UH we had several joint grants and projects and we continue to work together. Most of our collaborative work has been in the area of natural gas conversion and upgrade, including this one.”
This will be Grabow’s first project with Teixeria.
“It is the first time that I am working with him, but I’m excited about it because he brings many fresh ideas to the table,” Grabow said.
The project, “Precise but Tunable Reactions Through Tunably Precise Surfaces,” was approved by the NSF’s Emerging Frontiers and Multidisciplinary Activities (EFMA), which targets important, cutting-edge opportunities and long-term challenges for engineering that may address national needs.
According to Grabow, their goal is to deal with problems related to distributed natural resources, such as “stranded” natural gas.
“The term refers to the fact that many natural gas resources are in areas that are not easily accessible due to the lack of infrastructure,” he said. “Another example is flaring at refineries or oil wells, which is the process of simply burning the light gases, because there is no economic use for them. Considering the low value of natural gas, its compression or liquefaction and transport to large, centralized processing facilities is simply not a viable option.”
Ideally, Grabow said their work would lead to much smaller, flexible reactors, which can convert natural gas and form value-added chemicals on-site.
“We are proposing to work on small reactors that can be transported to where the natural gas or methane is found,” he explained. “The smaller reactor could be skid-mounted and fit inside a standard shipping container. By flipping the transportation problem and bringing the reactor to the feedstock, we hope to find a solution enabling the profitable use of otherwise in accessible natural resources.”
Doing this requires the development of new scientific techniques though, Grabow said.
“The scientific novelty is that the small reactor would not the operated at steady state, which is standard in the petrochemical industry,” he said. “Using intentionally imposed dynamic operating conditions, we will try to improve the reactor performance while also increasing the lifetime of the catalyst inside the reactor. The dynamic operation includes variations in pressure, feed composition or temperature.”
Grabow described rich and lean cycling as an example of a process that could be used.
“In the lean phase, we have excess oxygen, which can quickly oxidize the catalyst surface,” he said. “Then we would switch to rich conditions with excess methane to quickly reduce the oxidized catalyst. By switching between lean and rich conditions, we hope to speed up each half of the reaction – oxidation and reduction. If a stoichiometric ratio of methane and oxygen were used with steady-state, or time invariant conditions, then oxidation and reduction must occur at the same time and the catalyst must be designed to compromise between the requirements for both half reactions.”
About $750,000 of the award will cover the research being done at UH. Grabow said that between himself, Harold and Bollini, he felt that they had a well-rounded group of skills.
“Together, we form a strong team that spans theory and simulation, catalysis, kinetics and reaction engineering,” he said. “Our focus will be the development of the science of transient catalysis. Catalysis today is mostly studied at steady-state, and transient phenomena are rarely considered. We want to leverage the transient behavior and turn it into an advantage, but many simulation tools, for example, are only developed for steady-state.”
The work will feature a combination of computational methods along with experimentation, Grabow said in description of his work.
“I will be leading efforts to develop models that capture the transient kinetics of methane oxidation and reforming,” he said. “The kinetic model will be tested and verified against experiments in our Temporal Analysis of Products (TAP) reactor. It’s a delicate and rare piece of equipment, and only four TAP reactors are currently operational in the US.”
When it came to Harold and Bollini, Grabow said their focus would be on reactor scale modeling and kinetic experiments.
“Dr. Harold will be focusing on multi-scale models describing spatio-temporally – space and time resolved concentration and temperature profiles measured inside a reactor,” Grabow said. “Dr. Bollini will primarily focus on finding dynamic reaction conditions that prevent deactivation and prolong the catalyst lifetime.”
Grabow noted that there were obvious practical applications for their work when it came to industry usage.
“As with most NSF projects, this is a fundamental science and engineering project,” he said. “There is strong interest in building small, flexible reactors for distributed manufacturing, but the challenges are very different from established practice in industry. The science of transient kinetics and dynamically operated reactors is much less developed than it is for steady-state processes. Thus, our project will build a scientific and engineering foundation to make distributed manufacturing with dynamically operated, small-scale reactors a reality.”