A Brigham Young University professor widely recognized for his research into the process of turning coal into gas told an audience at the annual meeting of the world's largest scientific society that the technology may, for the first time, be financially compelling, thanks to concerns about global warming.
Larry Baxter, professor of chemical engineering, was part of a panel discussion titled "Coal Gasification: Myths, Challenges and Opportunities" presented Friday, Feb. 15, at the conference of the American Association for the Advancement of Science, the organization that publishes the journal Science. Gasification is the process of releasing coal's energy with extremely high temperatures but without enough oxygen to burn it all.
"Global warming issues may create gasification's best chance for success," Baxter said of the technology that has been used in rudimentary form since World War II. "Gasifiers produce a nearly pure carbon dioxide stream that may be more easily captured and stored than most other processes."
Gasification has potential contributions to both transportation and electrical power energy markets. With ongoing concerns about the price and availability of oil, populous countries like the U.S. and China with large coal reserves are exploring other energy options. Gasification has been appealing because it can turn coal or biomass into transportation fuel. In fact, Nazi Germany and South Africa under apartheid did so when faced with oil embargoes. On paper, gasification is also 50 percent more efficient at turning energy from coal into electricity than traditional coal burning. These efficiency advantages have proved difficult to achieve in practice, however, and most practical gasifiers generate power with about the same efficiency as a modern coal-fired power plant.
"Gasification has never really found its footing in the U.S. as either a transportation fuel or power generation technology because of problems of implementation and costs," Baxter said, noting that the complex process costs more to build and is more difficult to maintain than traditional oil refinement for motor fuel or coal-fired plants for electricity.
But Baxter foresees federal regulations that will increase costs for coal-burning plants by restricting the amount of carbon that can be emitted into the atmosphere and contribute to global warming. Many states, such as California, already have such restrictions. Under those circumstances, building and using a coal gasifier will be economically competitive with separating and capturing the carbon dioxide from traditional plants.
"Until now, engineers could see technical benefits with gasification, but they didn't translate into the business advantages," Baxter said. "Now, both engineers and business managers are interested."
Baxter actively promotes and researches renewable energy options such as biomass, wind, solar and hydro power but predicts that even once these options achieve widespread use, they will fail to meet energy demand. In addition to reducing consumption, Baxter believes fossil fuels must remain part of the world's energy solution.
"There's no rational near-term energy future that does not involve continued use of fossil fuel," he said. "If we emit that CO2, we either have to throw up our arms and face the consequences of global warming or use fossil-based power supplies in new ways that limit the emissions.
"I've researched coal and biomass gasification for a long time," Baxter continued. "It's still going to be more expensive than current techniques, but it will be cost-competitive compared with most other processes that include CO2 capture and storage. Coal gasification in the future could become as important as coal combustion is to us right now."
Baxter's expertise includes experimental work and computer models of the gasification process, but his presentation at AAAS focuses on modeling. He and his students write computer programs that describe the detailed environment (temperature, pressure, reaction rates, velocity and composition) inside a gasifier. They have found that the part of the coal that does not burn influences the process's operation and design more than the part that does. Baxter's team is developing ways to describe this leftover slag's properties and its interaction with the lining of the metal container in which gasification takes place.
"Professor Baxter is a world-recognized expert in combustion and energy issues," said Richard Rowley, chair of BYU's department of chemical engineering in the Ira A. Fulton College of Engineering & Technology. "He is a prolific researcher and his expertise on important issues relating to world energy policies are in high demand. With the nation's energy needs at a forefront and with the high level of coal resources in this country, Professor Baxter's work on coal gasification is not only of scientific interest but also of great importance to all of us."
Writer: Marissa Ballantyne