Posts Tagged ‘carbon dioxide’
Tuesday, July 16, 2013 @ 06:07 PM gHale
A water-soluble catalyst can electrocatalytically transform carbon dioxide into a useful chemical feedstock.
With the global demand for fuel is rising along with carbon dioxide levels in the atmosphere, this new development could actually fall into the category of a win-win situation.
Studies attempted to address the global carbon imbalance by exploring ways to recycle carbon dioxide into liquid fuels. Formate, the anion of formic acid, is an intermediate of carbon dioxide reduction and can end up used as a fuel in formic acid fuel cells.
The catch is, however, the selective production of formate, without using organic solvents, is challenging. Water, being inexpensive and environmentally-friendly, is obviously preferred over organic solvents as a reaction medium. On the other hand, the reduction of carbon dioxide in water ends up complicated by the reduction of water to hydrogen being a more kinetically favorable process.
But that all may change as Thomas Meyer, Maurice Brookhart and Peng Kang at the University of North Carolina designed an iridium pincer catalyst that can selectively reduce carbon dioxide into formate in almost pure water. Formate ends up made in a 93 percent yield with no other reduced carbon products formed at the same time. Notably, the catalyst does not catalyze proton reduction to form hydrogen molecules although a small amount of background hydrogen ends up at the electrode.
Wenzhen Li, an expert in the electrochemical reduction of carbon dioxide at Michigan Technological University said this exciting work reports such a catalyst for the first time. The only problem he sees is that formate and the catalyst are both water-soluble, so an input of energy would end up required to separate formate from the solution.
“It would be even more interesting to develop a [similar] catalyst to further reduce carbon dioxide to carbon monoxide or even hydrocarbons,” he said.
The group is now hunting for more efficient catalysts and ways to immobilize them on electrodes.
Monday, June 24, 2013 @ 09:06 AM gHale
There is a new and inexpensive catalyst that uses electricity generated from solar energy to convert carbon dioxide into synthetic fuels for powering cars, homes and businesses.
Gold and silver represent the “gold standard” in the world of electrocatalysts for conversion of carbon dioxide to carbon monoxide. University of Delaware (UD) chemist Joel Rosenthal and his research team have pioneered the development of a much cheaper alternative to these pricey, precious metals. It is bismuth, a silvery metal with a pink hue that’s a key ingredient in Pepto-Bismol, the same cure all for settling an upset stomach.
An ounce of bismuth is 50 to 100 times cheaper than an ounce of silver, and 2,000 times cheaper than an ounce of gold, Rosenthal said. Bismuth is more plentiful than gold and silver, it is well distributed globally and is a byproduct in the refining of lead, tin and copper.
Moreover, Rosenthal said his UD-patented catalyst offers other important advantages: Selectivity and efficiency in converting carbon dioxide to fuel.
“Most catalysts do not selectively make one compound when combined with carbon dioxide — they make a whole slew,” Rosenthal said. “Our goal was to develop a catalyst that was extremely selective in producing carbon monoxide and to power the reaction using solar energy.”
Many of us hear ‘”carbon monoxide” and think “poison.”
“It’s true that you do not want to be in a closed room with carbon monoxide,” Rosenthal says. “But carbon monoxide is very valuable as a commodity chemical because it’s extremely energy rich and has many uses.”
Carbon monoxide works industrially in the water-gas shift reaction to make hydrogen gas. It also is a prime feedstock for the Fischer-Tropsch process, which allows for the production of synthetic petroleum, gasoline and diesel.
Commercial production of synthetic petroleum is under way or in development in a number of countries, including Australia and New Zealand, China and Japan, South Africa and Qatar.
Rosenthal said if carbon dioxide emissions become taxed in the future due to continuing concerns about global warming, his solar-driven catalyst for making synthetic fuel will compete even better economically with fossil fuels.
“This catalyst is a critically important linchpin,” Rosenthal said. “Using solar energy to drive the production of liquid fuels such as gasoline from CO2 is one of the holy grails in renewable energy research. In order to do this on a practical scale, researchers need inexpensive catalysts that can convert carbon dioxide to energy-rich compounds. Our discovery is important in this regard, and demonstrates that development of new catalysts and materials can solve this problem. Chemists have a big role to play in this area.”
Rosenthal credits a scientific article published during America’s first energy crisis in the 1970s for piquing his interest in bismuth. At that time, researchers were examining the conversion of carbon dioxide to carbon monoxide using electricity and metal electrodes. The research went bust in the early 1980s when federal funding dried up. Rosenthal picked up the trail and blazed a new one.
“With this advance, there are at least a dozen things we need to follow up on,” Rosenthal notes. “One successful study usually leads to more questions and possibilities, not final answers.”
Thursday, September 6, 2012 @ 07:09 PM gHale
Shell, Chevron and Marathon Oil will build a carbon capture and sequestration mechanism into their 225,000 barrels per day Athabasca Oil Sands Project, which they feel when the system is ready in 2015, it will be able to capture 1 million metric tons a year of carbon dioxide and inject it a mile underground.
The oil sands are more carbon intensive than other sources of oil because the sludge must undergo a partial refining process, or an upgrade, before it’s thin enough to flow through pipelines. That upgrading process requires a lot of heat, which comes from burning natural gas, which generates quite a bit of carbon dioxide.
The Quest CCS project will capture the carbon dioxide that comes out of the Scotford Upgrader near Edmonton, Alberta, then take it by pipe about 50 miles north where it will inject underground between impermeable layers of rock. Eliminating all that carbon dioxide will effectively reduce the emissions by 35%.
Quest will cost $1.4 billion, about half of which will be put up by the government of Alberta, paid out of a $2 billion fund specifically created to finance carbon capture technologies.
Chevron is no stranger to CCS; at its giant Barrow Island LNG project in Australia, the oil giant is building a system to inject 3.4 million tons of carbon dioxide a year into the earth. That CO2, however, separates out of the natural gas harvested from the Gorgon fields.
Tuesday, June 12, 2012 @ 04:06 PM gHale
A new property of flames allows for the ability to control reactions at a solid surface in a flame now opens up a whole new field of chemical innovation.
Chemists now say their previous understanding of how flames interact with a solid surface was incorrect, said researchers at the University College London (UCL). For the first time, they showed they can control a particular type of chemistry, called redox chemistry, at the surface.
This finding has wide implications for future technology, for example in detection of chemicals in the air, and in developing our understanding of the chemistry of lightning. It also opens up the possibility of being able to perform nitrogen oxide and carbon dioxide electrolysis at the source for the management of greenhouse gases.
Results of the study show that depending on the chemical make-up of the flame, scientists can record a distinctive electrical fingerprint. The fingerprint is a consequence of the behavior of specific chemical species at the surface of a solid conducting surface, where electrons can exchange at a very precise voltage.
“Flames can be modeled to allow us to construct efficient burners and combustion engines,” said Dr. Daren Caruana, from the UCL Department of Chemistry. “But the presence of charged species or ions and electrons in flames gives them a unique electrical property.”
“By considering the gaseous flame plasma as an electrolyte, we show that it is possible to control redox reactions at the solid/gas interface,” Caruana said.
The team developed an electrode system that can probe the chemical make-up of flames. By adding chemical species to the flame they were able to pick up current signals at specific voltages giving a unique electrochemical finger print, called a voltammogram.
The voltammograms for three different metal oxides — tungsten oxide, molybdenum oxide and vanadium oxide — are all unique. Furthermore, the team also demonstrated the size of the current signatures depend on the amount of the oxide in the flame. While this is possible and routinely done in liquids, this is the first time they saw it works in the gas phase.
UCL chemists showed there are significant differences between solid/gas reactions and their liquid phase equivalents. Liquid free electrochemistry presents access to a vast number of redox reactions, current voltage signatures that lie outside potential limits defined by the liquid.
The prospect of new redox chemistries will enable new technological applications such as electrodeposition, electroanalysis and electrolysis, which will have significant economic and environmental benefits.
“The mystique surrounding the properties of fire has always captivated our imagination,” Caruana said. “However, there are still some very significant technical and scientific questions that remain regarding fire and flame.”
Wednesday, May 16, 2012 @ 06:05 PM gHale
Fracking is undergoing more scrutiny in California as oil and gas regulators want to propose new regulations and re-examine existing rules for underground injection wells.
The Department of Conservation’s Division of Oil, Gas, and Geothermal Resources (DOGGR) released a “road map” earlier this month outlining its plan to revisit the state’s oversight of underground injection wells to better protect drinking water supplies and workers.
As part of the process, the division said it would look at the use of carbon dioxide as an enhanced oil recovery tool, the storing of carbon dioxide in injection wells, and the reinjection of waste gas.
“It’s a to-do list of Division priorities for the near-term, some of which involve hydraulic fracturing regulations,” said DOGGR spokesman Don Drysdale.
Hydraulic fracturing, or fracking, involves pumping water, chemicals, and other substances into shale formations at high pressure to enhance natural gas extraction. Injection wells are for deep-underground storage of wastewater, including “flowback” water from fracking.
DOGGR said it will hold a series of public workshops to gather input for new fracking regulations, which it plans to propose by the end of the summer. Also, DOGGR said it will commission an independent study of the impact of fracking in California.
Monday, March 26, 2012 @ 02:03 PM gHale
The “hydrogen economy” is here and available and could begin commercial production in this decade, a scientist said.
Heat from existing nuclear plants could see use in the more economical production of hydrogen, with future plants custom-built for hydrogen production, said International Atomic Energy Agency’s (IAEA) Ibrahim Khamis, Ph.D., at the 243rd National Meeting & Exposition of the American Chemical Society (ACS).
“There is rapidly growing interest around the world in hydrogen production using nuclear power plants as heat sources,” Khamis said. “Hydrogen production using nuclear energy could reduce dependence on oil for fueling motor vehicles and the use of coal for generating electricity. In doing so, hydrogen could have a beneficial impact on global warming, since burning hydrogen releases only water vapor and no carbon dioxide, the main greenhouse gas. There is a dramatic reduction in pollution.”
Khamis said scientists and economists at IAEA and elsewhere are working intensively to determine how current nuclear power reactors — 435 are operational worldwide — and future nuclear power reactors could work in hydrogen production.
Most hydrogen production at present comes from natural gas or coal and results in releases of the greenhouse gas carbon dioxide. On a much smaller scale, some production comes from a cleaner process called electrolysis, in which an electric current flowing through water splits the H2O molecules into hydrogen and oxygen. This process, termed electrolysis, is more efficient and less expensive if water heats to form steam, with the electric current passed through the steam.
Khamis said nuclear power plants are ideal for hydrogen production because they already produce the heat for changing water into steam and the electricity for breaking the steam down into hydrogen and oxygen. Experts envision the current generation of nuclear power plants using a low-temperature electrolysis which can take advantage of low electricity prices during the plant’s off-peak hours to produce hydrogen. Future plants, designed specifically for hydrogen production, would use a more efficient high-temperature electrolysis process or couple with the thermochemical processes, which are currently under research and development.
“Nuclear hydrogen from electrolysis of water or steam is a reality now, yet the economics need to be improved,” Khamis said. He noted some countries are considering construction of new nuclear plants coupled with high-temperature steam electrolysis (HTSE) stations that would allow them to generate hydrogen gas on a large scale in anticipation of growing economic opportunities.
Khamis described how IAEA’s Hydrogen Economic Evaluation Programme (HEEP) is helping. IAEA has designed its HEEP software to help its member states take advantage of nuclear energy’s potential to generate hydrogen gas. The software assesses the technical and economic feasibility of hydrogen production under a wide variety of circumstances.
Wednesday, January 25, 2012 @ 03:01 PM gHale
A Hormel Foods subsidiary is facing “willful” safety law violations in connection with an accident last summer that severed a turkey plant worker’s arm, Occupational Safety and Health Administration (OSHA) officials said.
Shawn Redman, a 35-year-old veteran employee, was cleaning equipment July 20 at a Jennie-O Turkey Store processing plant in Barron, WI, when he caught his arm in a moving production line. Doctors were able to reattach the arm after emergency personnel flew him to a hospital.
Jennie-O should not allow cleaning of any sort while the production line is running, said Rhonda Burke, an OSHA spokeswoman. The agency has proposed fines of $318,000.
Austin. MN-based Hormel can contest OSHA’s findings and penalties; the company said in a statement that it’s reviewing the citations. Jennie-O employs 1,200 at its Barron plant and is one of the nation’s largest turkey processors.
OSHA issued 11 citations to Jennie-O, seven of them deemed “serious” and four “willful.” OSHA issues willful violations only when it believes employers have demonstrated “intentional, knowing or voluntary disregard” for safety rules, or “plain indifference” to worker safety and health.
The company is “committed to being a leader in our industry for employee safety. We have an extensive safety program designed to meet regulatory requirements, which includes ongoing employee training,” said Jennie-O’s human resources Vice President, Pat Solheid.
Redman was cleaning in a room in which the company uses carbon dioxide to kill the turkeys, which are shackled to a conveyor. OSHA cited Jennie-O for not cutting power to the line while Redman was cleaning, and for not adequately ensuring the room was free of carbon dioxide while he worked.
Also, the agency said Jennie-O didn’t have an attendant to oversee Redman when he entered and left the room. After the accident, Redman had to walk down a flight of 25 stairs and 200 feet across a production floor to flag down a co-worker, OSHA said.
Thursday, January 12, 2012 @ 06:01 PM gHale
By Nicholas Sheble
For the first time, comprehensive greenhouse gas (GHG) data reported directly from large facilities and suppliers across the U.S. are easily accessible to the public via the Environmental Protection Agency’s (EPA) GHG Reporting Program.
The 2010 GHG data released Wednesday includes public information from facilities in nine industry groups that directly emit large quantities of GHGs.
A greenhouse gas is a gas in the atmosphere that absorbs and emits radiation in the thermal infrared range. This process is the cause of global warming. GHGs include water vapor, carbon dioxide, methane, nitrous oxide, and ozone.
Three coal-fired power plants owned by Southern Company led the emitter hit parade and each released more than 20 million metric tons of carbon dioxide equivalent in 2010.
Two of the plants, Scherer and Bowen, are in Georgia. The third, James H. Miller Jr., is in Alabama.
The fourth-largest emitter was the Martin Lake, TX power plant of Energy Future Holdings Corporation subsidiary, Luminant.
Duke Energy Corp.’s largest plant, the Gibson plant in Indiana, came in fifth.
“Thanks to strong collaboration and feedback from industry, states and other organizations, today we have a transparent, powerful data resource available to the public,” said Gina McCarthy, assistant administrator for EPA’s Office of Air and Radiation.
“The GHG Reporting Program data provides a critical tool for businesses and other innovators to find cost- and fuel-saving efficiencies that reduce greenhouse gas emissions, and foster technologies to protect public health and the environment,” McCarthy said.
One can view and sort GHG data for calendar year 2010 from over 6,700 facilities by facility, location, industrial sector, and the type of GHG emitted. This information helps communities to identify nearby sources of GHGs, help businesses compare and track emissions, and provide information to state and local governments.
GHG data for direct emitters show that in 2010:
• Power plants were the largest stationary sources of direct emissions with 2,324 million metric tons of carbon dioxide equivalent (mmtCO2e), followed by petroleum refineries with emissions of 183 mmtCO2e.
• CO2 accounted for the largest share of direct GHG emissions with 95 percent, followed by methane with 4 percent, and nitrous oxide and fluorinated gases accounting for the remaining 1 percent.
• One hundred facilities each reported emissions over seven mmtCO2e, including 96 power plants, two iron and steel mills, and two refineries.
Click here to access EPA’s GHG Reporting Program Data and Data Publication Tool. On the right side of the page click on “View GHG data” and then play around with the interactive sorting functions to find facilities of interest.
Nicholas Sheble (firstname.lastname@example.org) is an engineering writer and technical editor in Raleigh, NC.
Tuesday, December 6, 2011 @ 03:12 PM gHale
Five oil refineries in Washington state are under pressure to clean up their airborne emissions as a result of a district court decision late last week.
The state and regional clean air agencies have been violating the Clean Air Act by not requiring the refineries to reduce pollution using what is termed “reasonably available technology,” said the Washington Environmental Council and the Sierra Club.
Attorney Janette Brimmer with Earthjustice argued the case for the plaintiffs and summarizes the main question.
“What was the state’s obligation, or the regional clean air agencies, to set basic minimum standards for this kind of pollution — like methane and nitrous oxide and carbon dioxide — from refineries? And the state was saying, ‘We don’t think we have to do this, at least not under our federally-enforceable plan.’ And we said, ‘Well, we think you do have to do it.’ ”
The state and regional clean air agencies said they’ve been waiting for more guidance from the U.S. Environmental Protection Agency (EPA), but U.S. District Court Judge Marsha Pechman said the agencies have a responsibility to enforce the state clean air plan that’s already in place, ruling in favor of the plaintiffs.
One issue raised in court is Washington’s State Implementation Plan for regulating air pollution is tougher in some ways than federal greenhouse gas standards, and the agencies weren’t sure they could enforce it. However, the judge pointed out the EPA has “repeatedly approved” the state plan.
“The reality is that, despite a lot of good policy statements about greenhouse gases and climate change in Washington, we really have not regulated greenhouse gas pollution very much, particularly from existing sources like these big refineries,” Brimmer said.