Researchers at the Office of Fossil Energy’s National Energy Technology Laboratory (NETL) are using their world-class supercomputer to learn more about the chaotic chemical reactions that occur in the coal gasification process—knowledge that can lead to cleaner, more efficient, and more economical use of coal.
It’s difficult to remove contaminants from solids such as coal. One solution is to gasify the coal—to convert it into gaseous components—and then separate and remove environmental contaminants, such as the greenhouse gas carbon dioxide (CO2). However, for scientists developing new gasification technologies, facilities, and procedures, the process looks like a big, hectic three-ring circus with difficult-to-predict chemical reactions as the performers.
When coal is fed into a reactor, heated in the gasification process, and mixed with steam and oxygen, coal particles—like circus acrobats—rise, pivot, shake, and snake their way through gas pockets, bounce off the walls of the reactor chamber, and slam into each other, all while chemically reacting.
Researchers need to know how those many chemical reactions—under the influence of factors such as particle size, temperature, pressure, and other conditions—affect final outcomes. Thanks to the availability of one of the fastest, most energy-efficient supercomputers in the world, NETL scientists no longer have to figure out gasification chaos through time-consuming trial and error.
NETL’s supercomputer is reducing the time and effort required to conduct multiphase flow analyses—the examination of how two or more distinct items, like coal, water, and gas, interact. Jordan Musser, a physical scientist at NETL, said he uses the supercomputer to obtain quick enhanced visualization and data analysis of multiphase flow situations.
"The models we can run let us investigate design parameters like inflow gas composition, gas temperatures, and coal properties,"Musser said, "so we can see how those factors affect the efficiency and performance of gasification."
He added that the supercomputer can run simulations on scales that range from the molecular level to entire power plants, providing enhanced visualization and data analysis, which scientists use to predict operational characteristics.
Before computer modeling, the only way for researchers to understand and compensate for the many chemical reactions involved with gasification was to make adjustments to the process, run them for several days in a full-scale gasifier, and then analyze the results.
Gasification, and its CO2-capturing potential, presents enough operational characteristics to warrant a supercomputer’s attention. Multiscale challenges are inherent in gasification. Sub-processes like gas-phase kinetics, turbulent flows, turbulence-chemistry interaction, evaporation and break-up of liquid fuels, heterogeneous reactions for solid fuels, and dense particle systems are just a few of the types of problems that scientists must analyze to move gasification technologies forward.
But the supercomputer work at NETL isn’t just about the hardware. NETL scientists have also created a software tool to help researchers run large-scale multiphase flow analysis projects on the supercomputer and on their own workstations or computer clusters. MFIX (Multiphase Flow with Interphase eXchanges) realistically models gas and particle dynamics, chemical reactions, and heat transfer involved with coal gasification and other power-generating combustion processes.
While researchers all over the world can download the free, open-source MFIX code and use it on their own workstations (as 2,600 users from 70 countries have already done), the program excels as a tool for large-scale projects on the NETL supercomputer and at other domestic and international supercomputer facilities.
"Right now, one project is running multiple large MFIX simulations to model a full commercial-scale gasifier,"Musser said. "It would be difficult, if not impossible, to run those models without the supercomputer."
Chris Guenther, director of NETL’s Computational Science Division, said the supercomputer is "accelerating research and development to address environmental concerns around power generation, speed the development of new cutting-edge technology, and enable us to troubleshoot and optimize existing technology. It’s all about making research on the next generation of fossil fuel systems faster, cheaper, and safer. This is the only supercomputer truly dedicated to fossil energy research. If you are researching fossil fuels, you are only constrained by your imagination.”
This month, NETL and many other of the Energy Department’s national labs are showcasing ways in which supercomputing is changing the way scientists conduct research and how the labs are driving high-performance computing to new heights. For more information, please visit the Energy Department’s national lab webpage.