A team of researchers at MIT has actually developed a promising approach to controlling methane emissions and removing it from the air, utilizing a economical and abundant kind of clay called zeolite. In this image, the zeolite, illustrated as the complex structure in the middle, takes in the methane that goes through it. Credit: Image: Darius Siwek
With special treatment, minerals called zeolites– commonly discovered in feline litter– can efficiently eliminate the greenhouse gas from the air, scientists report.
Methane is a much more powerful greenhouse gas than co2, and it has a noticable effect within the very first 2 years of its presence in the environment. In the current international environment negotiations in Glasgow, abatement of methane emissions was identified as a significant concern in attempts to suppress worldwide climate modification rapidly.
Now, a group of scientists at MIT has created a promising technique to controlling methane emissions and removing it from the air, utilizing a abundant and economical type of clay called zeolite. The findings are explained in the journal ACS Environment Au, in a paper by doctoral student Rebecca Brenneis, Associate Professor Desiree Plata, and two others.
By David L. Chandler, Massachusetts Institute of Technology
January 10, 2022
Although lots of people associate climatic methane with drilling and fracking for oil and gas, those sources only account for about 18 percent of global methane emissions, Plata says. The vast bulk of produced methane originates from such sources as slash-and-burn farming, dairy ore, farming and coal mining, wetlands, and melting permafrost. “A great deal of the methane that enters into the environment is from distributed and diffuse sources, so we began to consider how you might take that out of the atmosphere,” she says.
The response the scientists discovered was something dirt inexpensive– in reality, an unique sort of “dirt,” or clay. They used zeolite clays, a material so inexpensive that it is currently used to make cat litter. Dealing with the zeolite with a percentage of copper, the group found, makes the product really effective at taking in methane from the air, even at exceptionally low concentrations.
The system is basic in concept, though much work stays on the engineering information. In their lab tests, small particles of the copper-enhanced zeolite product, comparable to feline litter, were packed into a response tube, which was then warmed from the outside as the stream of gas, with methane levels varying from just 2 parts per million as much as 2 percent concentration, streamed through the tube. That variety covers everything that might exist in the atmosphere, down to subflammable levels that can not be burned or flared directly.
The procedure has numerous advantages over other techniques to removing methane from air, Plata states. Other methods tend to use pricey catalysts such as platinum or palladium, need heats of a minimum of 600 degrees Celsius, and tend to require complex cycling in between methane-rich and oxygen-rich streams, making the devices both more complex and more risky, as methane and oxygen are extremely combustible by themselves and in combination.
” The 600 degrees where they run these reactors makes it practically dangerous to be around the methane,” along with the pure oxygen, Brenneis states. “Theyre solving the problem by just developing a situation where theres going to be an explosion.” Other engineering complications also occur from the high operating temperature levels. Unsurprisingly, such systems have not discovered much use.
When it comes to the new procedure, “I believe were still surprised at how well it works,” states Plata, who is the Gilbert W. Winslow Associate Professor of Civil and Environmental Engineering. The process seems to have its peak effectiveness at about 300 degrees Celsius, which requires far less energy for heating than other methane capture processes. It also can work at concentrations of methane lower than other approaches can deal with, even small portions of 1 percent, which most approaches can not get rid of, and does so in air instead of pure oxygen, a major benefit for real-world implementation.
The approach transforms the methane into co2. That might sound like a bad thing, offered the worldwide efforts to fight co2 emissions. “A great deal of individuals hear co2 and they worry; they state thats bad,” Plata says. She points out that carbon dioxide is much less impactful in the environment than methane, which is about 80 times more powerful as a greenhouse gas over the very first 20 years, and about 25 times stronger for the very first century. This effect emerges from that truth that methane turns into carbon dioxide naturally in time in the atmosphere. By accelerating that procedure, this approach would significantly reduce the near-term environment impact, she says. And, even transforming half of the environments methane to carbon dioxide would increase levels of the latter by less than 1 part per million (about 0.2 percent of todays climatic co2) while conserving about 16 percent of total radiative warming.
The ideal area for such systems, the team concluded, would remain in places where there is a fairly concentrated source of methane, such as dairy barns and coal mines. These sources currently tend to have powerful air-handling systems in location, because an accumulation of methane can be a fire, health, and surge threat. To surmount the exceptional engineering details, the group has just been granted a $2 million grant from the U.S. Department of Energy to continue to develop particular equipment for methane removal in these kinds of locations.
” The key advantage of mining air is that we move a great deal of it,” she says. “You have to pull fresh air in to enable miners to breathe, and to reduce surge dangers from enriched methane pockets. The volumes of air that are moved in mines are enormous.” The concentration of methane is too low to ignite, but its in the catalysts sweet area, she states.
Adjusting the technology to specific sites ought to be relatively uncomplicated. The lab setup the group used in their tests consisted of “just a couple of elements, and the innovation you would put in a cow barn could be pretty simple too,” Plata states. Big volumes of gas do not stream that easily through clay, so the next stage of the research will focus on methods of structuring the clay product in a multiscale, hierarchical setup that will assist air flow.
” We need brand-new technologies for oxidizing methane at concentrations below those utilized in flares and thermal oxidizers,” states Rob Jackson, a professor of earth systems science at Stanford University, who was not included in this work. “There isnt an economical innovation today for oxidizing methane at concentrations listed below about 2,000 parts per million.”
Jackson adds, “Many concerns stay for scaling this and all similar work: How quickly will the catalyst foul under field conditions? Can we get the necessary temperature levels better to ambient conditions? How scaleable will such innovations be when processing big volumes of air?”
One possible major benefit of the brand-new system is that the chemical process involved releases heat. By catalytically oxidizing the methane, in effect the procedure is a flame-free type of combustion. If the methane concentration is above 0.5 percent, the heat launched is greater than the heat utilized to get the procedure began, and this heat could be utilized to create electricity.
The groups estimations reveal that “at coal mines, you could possibly create adequate heat to create electricity at the power plant scale, which is exceptional because it indicates that the device could spend for itself,” Plata says. “Most air-capture options cost a lot of cash and would never ever be successful. Our technology may one day be a counterexample.”
Utilizing the brand-new grant money, she says, “over the next 18 months were intending to demonstrate a proof of principle that this can operate in the field,” where conditions can be more tough than in the lab. Ultimately, they wish to have the ability to make devices that would be suitable with existing air-handling systems and could just be an additional component included location. “The coal mining application is implied to be at a stage that you might hand to an industrial home builder or user three years from now,” Plata says.
Recommendation: “Atmospheric- and Low-Level Methane Abatement by means of an Earth-Abundant Catalyst” by Rebecca J. Brenneis, Eric P. Johnson, Wenbo Shi, and Desiree L. Plata, 29 December 2021, ACS Environment Au.DOI: 10.1021/ acsenvironau.1 c00034.
In addition to Plata and Brenneis, the group consisted of Yale University PhD student Eric Johnson and former MIT postdoc Wenbo Shi. The work was supported by the Gerstner Philanthropies, Vanguard Charitable Trust, the Betty Moore Inventor Fellows Program, and MITs Research Support Committee.
Lots of people associate climatic methane with drilling and fracking for oil and natural gas, those sources just account for about 18 percent of international methane emissions, Plata says. “A lot of the methane that comes into the atmosphere is from dispersed and diffuse sources, so we started to believe about how you might take that out of the environment,” she says.
” The 600 degrees where they run these reactors makes it nearly harmful to be around the methane,” as well as the pure oxygen, Brenneis states. The concentration of methane is too low to ignite, however its in the catalysts sweet area, she says.
If the methane concentration is above 0.5 percent, the heat launched is greater than the heat used to get the process began, and this heat might be utilized to produce electricity.
