Posts tagged cause
CU-Boulder team develops potential new hydrogen fuel technology
Aug 1st
The CU-Boulder team has devised a solar-thermal system in which sunlight could be concentrated by a vast array of mirrors onto a single point atop a central tower up to several hundred feet tall. The tower would gather heat generated by the mirror system to roughly 2,500 degrees Fahrenheit (1,350 Celsius), then deliver it into a reactor containing chemical compounds known as metal oxides, said CU-Boulder Professor Alan Weimer, research group leader.
As a metal oxide compound heats up, it releases oxygen atoms, changing its material composition and causing the newly formed compound to seek out new oxygen atoms, said Weimer. The team showed that the addition of steam to the system — which could be produced by boiling water in the reactor with the concentrated sunlight beamed to the tower — would cause oxygen from the water molecules to adhere to the surface of the metal oxide, freeing up hydrogen molecules for collection as hydrogen gas.
“We have designed something here that is very different from other methods and frankly something that nobody thought was possible before,” said Weimer of the chemical and biological engineering department. “Splitting water with sunlight is the Holy Grail of a sustainable hydrogen economy.”
A paper on the subject was published in the Aug. 2 issue of Science. The team included co-lead authors Weimer and Associate Professor Charles Musgrave, first author and doctoral student Christopher Muhich, postdoctoral researcher Janna Martinek, undergraduate Kayla Weston, former CU graduate student Paul Lichty, former CU postdoctoral researcher Xinhua Liang and former CU researcher Brian Evanko.
One of the key differences between the CU method and other methods developed to split water is the ability to conduct two chemical reactions at the same temperature, said Musgrave, also of the chemical and biological engineering department. While there are no working models, conventional theory holds that producing hydrogen through the metal oxide process requires heating the reactor to a high temperature to remove oxygen, then cooling it to a low temperature before injecting steam to re-oxidize the compound in order to release hydrogen gas for collection.
“The more conventional approaches require the control of both the switching of the temperature in the reactor from a hot to a cool state and the introduction of steam into the system,” said Musgrave. “One of the big innovations in our system is that there is no swing in the temperature. The whole process is driven by either turning a steam valve on or off.”
“Just like you would use a magnifying glass to start a fire, we can concentrate sunlight until it is really hot and use it to drive these chemical reactions,” said Muhich. “While we can easily heat it up to more than 1,350 degrees Celsius, we want to heat it to the lowest temperature possible for these chemical reactions to still occur. Hotter temperatures can cause rapid thermal expansion and contraction, potentially causing damage to both the chemical materials and to the reactors themselves.”
In addition, the two-step conventional idea for water splitting also wastes both time and heat, said Weimer, also a faculty member at CU-Boulder’s BioFrontiers Institute. “There are only so many hours of sunlight in a day,” he said.
The research was supported by the National Science Foundation and by the U.S. Department of Energy.
With the new CU-Boulder method, the amount of hydrogen produced for fuel cells or for storage is entirely dependent on the amount of metal oxide — which is made up of a combination of iron, cobalt, aluminum and oxygen — and how much steam is introduced into the system. One of the designs proposed by the team is to build reactor tubes roughly a foot in diameter and several feet long, fill them with the metal oxide material and stack them on top of each other. A working system to produce a significant amount of hydrogen gas would require a number of the tall towers to gather concentrated sunlight from several acres of mirrors surrounding each tower.
Weimer said the new design began percolating within the team about two years ago. “When we saw that we could use this simpler, more effective method, it required a change in our thinking,” said Weimer. “We had to develop a theory to explain it and make it believable and understandable to other scientists and engineers.”
Despite the discovery, the commercialization of such a solar-thermal reactor is likely years away. “With the price of natural gas so low, there is no incentive to burn clean energy,” said Weimer, also the executive director of the Colorado Center for Biorefining and Biofuels, or C2B2. “There would have to be a substantial monetary penalty for putting carbon into the atmosphere, or the price of fossil fuels would have to go way up.”
C2B2 is an arm of the Colorado Energy Research Collaboratory involving CU-Boulder, the Colorado School of Mines, Colorado State University and the National Renewable Energy Laboratory in Golden. The collaboratory works with industry partners, public agencies and other institutions to commercialize renewable energy technologies, support economic growth in the state and nation and educate the future workforce.
For more information on the chemical and biological engineering department visit http://www.colorado.edu/chbe/. For more information on C2B2 visit http://www.c2b2web.org. For more information on the Biofrontiers Institute visithttp://biofrontiers.colorado.edu.
Noxious weeds on the city’s “hit” list
May 2nd
As a result of a state mandate to eliminate “List A” noxious weed species from all public and private property in Colorado communities, the City of Boulder is proposing an update to its existing weed ordinance to require property owners to remove the weeds from all properties.
“List A” weed species, as provided in the Colorado Noxious Weed Act, are plants that have yet to be well established in Colorado but are either present in small populations or are invasive in nearby states. There are two species of “List A” weeds that are of most concern within Boulder’s city limits: myrtle spurge and Japanese knotweed. The city was awarded a grant through the Colorado Department of Agriculture Noxious Weed Management Fund to assist in an educational plan.
“Early detection and eradication of these particular species can prevent them from becoming a major problem in Colorado,” said city Integrated Pest Management Coordinator Rella Abernathy. “Most of these plants are ‘escaped’ ornamental plants and many residents may not realize that they present a threat to the natural lands surrounding Boulder and are illegal to grow here.”
These noxious, invasive plants can negatively impact biodiversity, threaten endangered species, degrade native habitat, displace wildlife, increase soil erosion, damage streams and other wetlands and increase the risk and frequency of wildfires if allowed to spread. Boulder is in compliance with the Colorado Noxious Weed Act on city-owned properties but has not been enforcing the statue on private property.
The city will focus on education and outreach to notify the public of the requirements and to provide information for identification, environmentally-sound weed removal and suggested replacement plant options.
“A soft enforcement approach is being implemented with voluntary compliance being the goal and enforcement action being a last resort,” said Code Enforcement Supervisor Jennifer Riley. “However, ticketing is possible if property owners do not comply with repeated requests from officers to address illegal weeds.”
Education will begin with a “Purge Your Spurge” event on May 18 where residents are encouraged to pull their myrtle spurge and exchange it for free native plants. This event will occur as part of Boulder Community Day at the East Boulder Community Center, 5660 Sioux Drive, from 10 a.m. to 2 p.m. Other education efforts will include a webpage; fact sheets; media engagement; outreach to nurseries, landscapers and lawn care companies; and code enforcement officers who assist with education in the field.
“Identifying and removing noxious weeds from private property can take some effort, but it’s important to prevent these weeds from spreading to our neighbors’ yards and ultimately to natural areas,” said Abernathy. “Fortunately, only two of the weeds from the list are widespread within the Boulder city limits, myrtle spurge being the most common. We want to make sure people can easily identify the weeds, know how to remove them safely and know what native plants can be used to replace them.”
Myrtle spurge has been commonly used as a decorative plant. People should be aware that it contains a white sap that can cause skin irritation including blistering if touched. Those removing it should wear long sleeves, long pants, gloves and eye protection. Removing at least four inches of the root is recommended to prevent its return. It should be placed in a plastic bag and tightly fastened. DON’T compost noxious weeds as that will cause the weed to spread.
The city’s weed ordinance is expected to be modified through a City Manager rule change, which will be published in the Daily Camera on May 3, as well as on the city’s website. Public feedback will be accepted until May 20. The rule is anticipated to go into effect on June 1, 2013.
For more information or to provide feedback on the proposed City Manager’s rule, contact Rella Abernathy at 303-441-1901.
— CITY OF BOULDER NEWS RELEASE –
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Boulder County Open Space: Picture Rock and Nelson Loop Trails Closed
Mar 7th
Closed trailheads lie just southwest of the Town of Lyons
Boulder County, Colo. – The Picture Rock Trail at Heil Valley Ranch and the Nelson Loop at Hall Ranch are closed until further notice.
Recent and forecasted snowfall, combined with expected warm temperatures, will cause extremely muddy conditions and significant trail damage if these trails are used. The trails will reopen when staff determines conditions have improved and are stable.
All other trails at Heil Valley Ranch and Hall Ranch remain open at this time.
Check the latest trail conditions at www.BoulderCountyOpenSpace.org/trailconditions.
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