Scientists unveil tech to slash 90% of CO2 from gas plants

Source: By Carlos Anchondo, E&E News reporter • Posted: Sunday, July 26, 2020

Researchers have developed a new carbon capture technology that they say has the potential to drive significant emissions reductions cheaply at natural gas-fired power plants, according to a study released yesterday.

The research, published in the journal Science, involves a material known as a metal-organic framework (MOF) enhanced with nitrogen-containing molecules used to capture carbon dioxide from a power plant’s emissions stream. The team used low-temperature steam to “regenerate” the MOF for repeated use, meaning that less energy was required for carbon capture than what is typical.

Scientists from Lawrence Berkeley National Laboratory (LBNL) and the University of California, Berkeley, led the research, which was funded by Exxon Mobil Corp.

Jeffrey Long, a UC Berkeley chemistry professor and paper co-author, said considering natural gas’s dominant share of U.S. power generation — the fuel surpassed coal in 2016 as the country’s leading generation source — it’s important to direct attention to natural gas plants and how to trap CO2 inefficiently before it enters the atmosphere.

Long said the materials are particularly designed to grab CO2 from a plant’s flue-gas stack — where gases go into the air — so it could be stored underground or put to other use. The technology is able to capture more than 90% of emitted CO2, which makes up roughly 4% of exhaust gas that comes out of a natural gas power plant, he said.

By comparison, the gas stream from a coal-fired power plant is between 13% and 15% CO2, he said.

“Capturing 90% of that more dilute stream of gas is actually technically challenging,” Long said, “and we had to specifically design this material to be able to do that.”

The MOF materials also were six times better at removing CO2 from flue gas than existing amine-based scrubbers, according to the study.

Using low-grade steam to regenerate the new materials provides “a pathway for a viable solution for carbon capture at scale,” Simon Weston, a senior research associate and the project lead at ExxonMobil Research & Engineering Co., said in a statement.

Sarah Nordin, a spokesperson for Exxon, said Weston, Long and the other researchers have been working toward this “potential carbon capture solution” for eight years. The new material captures CO2 in large quantities without “co-capturing O2 or N2,” Nordin said in an email.

“While there are other materials that do some of the above, this material stands out because it does all of the above very well,” Nordin said.

Still, more research will be needed to move the technology to a larger-scale pilot and ultimately to industrial scale, she said.

Only two power plants in the world — both for coal-fired power generation — are outfitted with CCS technology, according to the Global CCS Institute. Multiple large-scale CCS facilities for natural gas power generation are in early or advanced development, the organization said.

Nordin said Exxon’s collaboration with LBNL and UC Berkeley is part of the oil and gas company’s commitment “to finding meaningful and scalable solutions to meet global energy demand, while also minimizing the environmental impacts of energy use, including the risks of climate change.”

John Thompson, technology and markets director at the Clean Air Task Force, said Congress needs to enact more policies that help innovations like those in the research become commercial products, including increased laboratory funding.

“That being said, we also need to ensure the 30+ carbon capture projects in various stages of development will be built to enable learning-by-doing,” Thompson said in an email.