Protecting the planet with microwave technologies
On this Earth Day, we’re celebrating some of our Leidos employees who are working to develop technologies that are helping to protect our planet by reducing greenhouse gas emissions from industrial processes.
Of the 160 Leidos personnel who support the $365 million contract to the Department of Energy’s National Energy Technology Laboratory (NETL), four are female scientists who are working on microwave technologies that may significantly reduce the production of greenhouse gases from industrial processes. Their innovative research can change the way we use our abundant fossil resources (coal, oil, and natural gas) to provide sustainable energy for the American economy.
Drs. Christina Wildfire, Pranjali Muley, Yan Zhou, and Candice Ellison, from Leidos’ Energy and Environment Division are part of NETL’s Reaction Engineering Team. They are working together on critical microwave applications projects that can significantly reduce the energy requirements for converting fossil resources to useful chemicals, accommodate the use of renewable energy resources and a means of turning plastic wastes into economically useful chemicals.
The women, with Ph.Ds. in engineering or chemistry, work at NETL’s Morgantown, West Virginia laboratory. Their team specializes in using microwaves to convert fossil fuels into clean fuels such as hydrogen, as well as marketable chemicals, and products. Their work for NETL includes designing and installing experimental infrastructure for conducting fundamental investigations of molecular level microwave phenomena, a capability that does not currently exist in the scientific community.
Why microwaves?
While conventional heating works by heating reacting materials from the outside, microwaves are able to target materials on a molecular level in a way that avoids heating the entire system. Microwaves can also induce other chemical phenomena such as an increase in the selectivity and reaction speed of catalysts. The result is an almost instantaneous startup of energy efficient conversion processes that can replace energy intensive conversion processes currently in use.
Drs. Wildfire, Muley, Zhou, and Ellison are focusing on using microwaves to provide rapid and selective energetics on a molecular level. The microwaves allow for fossil fuels and other feedstocks to be used in ways other than traditional methods. For example, avoiding the need for large-scale, capital-intensive facilities, microwave-based conversion processes can be scaled down in modular “point-of-use” applications, such as generation of hydrogen for transportation use. Alternately their research may allow power plants to ‘load follow’ (go from 100% to 40% power within, say, 20 minutes), making the plant complementary to maintaining a stable load on a grid that includes renewables. Finally, microwave enhanced processes can more readily integrate with renewable energy sources to facilitate energy storage applications.
“Microwaves have many advantages over traditional thermal heating,” said Wildfire, who has been at NETL since 2016, the longest tenure of the four Leidos women. “For instance, you don’t need to heat up the entire system, which for high-temperature processes like coal gasification, can save a considerable amount of energy. Microwaves can target microwave-active materials, like the carbon in coal, resulting in higher product yields and greater selectivity, while not interacting with minerals like metal oxides.”
The selectivity of microwave interaction is a powerful tool when using catalyst materials for chemical processes. The NETL team has found that exposing certain catalyst materials to microwave radiation improves their selectivity and speed of reaction dramatically in some chemical processes; and are working to better understand the nature of such reactions in order to make them more useful in industrial scale processes.
Upcycling plastic waste
Plastic waste, in the form of discarded bottles, containers and wrapping, does not readily break down in the environment; and at their current rate of generation threatens to engulf our planet. The NETL team has been involved in fundamental research on ways to convert plastic waste into useful chemical components including hydrogen.
Microwave radiation disassembles the component polymers in plastic wastes, such as water bottles, and allows their ‘building block’ chemicals to be collected for reuse. Today, Dr. Muley is exploring the role of electromagnetic heating as a source of energy and is currently working on plastic waste conversion technology. This is important work, considering the world has produced over nine billion tons of plastic since the 1950s and two-thirds of it is in the environment - including our oceans. Even more disturbing, plastic degenerates in 450 years or…never.
“The team’s research is working to lower greenhouse gas emissions and enhance industrial processes,” said Muley. “Chemical conversion is one of the ways microwaves can be used to yield valuable chemicals from otherwise unused waste products.”
“For instance, we are developing processes to capture carbon dioxide from power plants and convert them to valuable chemicals, upcycling plastic or biomass waste to make clean-burning fuels and polymer building blocks [chemicals for creating new materials],” Muley said.
Dr. Muley uses numerical and computational modeling to model microwave enhanced conversion processes and provide the necessary data to scale up reactions from the laboratory to commercial use.
Since they can be scaled to fit the quantity of available feedstock, microwave-based plastic waste conversion processes could be set up at the plastic waste sorting facilities for plastic-to-chemical conversion or for localized ammonia synthesis near gas wells and farms.
Recovering energy from plastic waste will not only clean up landfills and save ocean life, it could offset the use of fossil fuels for many industrial processes
Converting methane to low carbon fuels and products
Dr. Zhou has the task of looking for cost-efficient ways to convert methane to syngas or other valuable chemicals using microwaves. All traditional methods that use and reform methane as an energy source release carbon dioxide, toxic gases, and undesired waste. That’s what Dr. Zhou is working to eliminate, but it’s tricky. Since the early 1900s, scientists have used catalysts to convert methane to useful products, which has been advantageous in terms of product yield. However, the methods required extreme process conditions, making them consume more energy than they produce.
Dr. Zhou is looking at how a catalyst charged by microwaves may change the chemical synthesis route. Microwaves could selectively heat and activate a catalyst and reduce the overall energy consumption. Working directly with her NETL customer counterparts, Dr. Zhou uses a patent-pending methane conversion technology to employ microwave-assisted catalysis for chemical conversion.
“Using microwaves could intensify the catalytic conversion process and reduce energy requirements while inducing higher yields and greater selectivity,” Zhou said. “Natural gas, primarily composed of methane, is a cheap and abundant domestic resource that can be converted to a wide range of products, including liquid transportation fuels and a wide range of chemical intermediates. However, traditional catalysts used in powder form (in laboratory experiments) can be expensive and hard to scale up to a commercial scale reactor process.”
“Development of catalyst coating processes that use the minimum amount of catalyst to coat on various substrates, could lower the cost of the catalyst while maintaining its activity. Furthermore, since microwave selectively heats the catalyst, using the catalyst-coated substrates could further reduce the overall energy consumption,” said Zhou. Dr. Zhou is developing coating processes and studying different forms of substrates for catalysts used for microwave reactions. Her goal is to find the best method to coat catalysts on substrates for higher conversion efficiency. Efficient methane conversion could produce syngas for automotive fuel or other useful products.
Changing how we look at reaction chemistry
Dr. Ellison, a research engineer with the Leidos team for three years, is exploring the use of microwaves to improve coal gasification. Gasification technology, basically, is a process that converts solid or liquid fuel—in this case, coal—into a gaseous or liquefied fuel that can be burned to release energy. The United States has more than 350 years of recoverable coal reserves, making this fossil fuel a good choice.
The goal is to convert coal into energy-dense syngas in a cleaner, more efficient way than conventional technologies. The unique properties of microwave heating allow coal gasification to occur at lower temperatures and with shorter reaction times--all while generating higher syngas yields.
This research on microwave gasification may lead to better process efficiency at production scale. Dr. Ellison also studies how microwaves interact with coal and catalysts by characterizing their dielectric (or insulating) properties.
Materials like coal do not conduct electricity, but when placed in an electromagnetic microwave field, their electrons shift slightly, causing them to become polarized. These dielectric properties help the team understand how microwaves heat materials and help researchers build numerical models to predict how a material will behave during microwave processing.
“The ability to transform reaction pathways by microwave reaction engineering is changing the way we look at reaction chemistry,” said Ellison. “Technologies being developed by NETL’s microwave engineering research can help solve the toughest energy challenges, which will help develop clean and efficient energy solutions.”
