Conventional coal-fired electric generating facilities capture just a third of the energy available in the fuel they burn. Fuel cells can convert significantly more of the energy, approximately 50 percent. If gas turbines and fuel cells could be combined into hybrid systems, researchers believe they could capture as much as 80 percent of the energy, reducing the amount of coal needed to produce a given amount of energy, potentially cutting carbon emissions.
...But that would only be possible if the fuel cells could run for long periods of time on coal gas, which now deactivates the anodes after as little as 30 minutes of operation.
The carbon removal system developed by the Georgia Tech-led team uses a vapor deposition process to apply barium oxide nanoparticles to the nickel-YSZ electrode. The particles, which range in size from 10 to 100 nanometers, form "islands" on the nickel that do not block the flow of electrons across the electrode surface.
When water vapor introduced into the coal gas stream contacts the barium oxide, it is adsorbed and dissociates into protons and hydroxide (OH) ions. The hydroxide ions move to the nickel surface, where they combine with the carbon atoms being deposited there, forming the intermediate COH. The COH then dissociates into carbon monoxide and hydrogen, which are oxidized to power the fuel cell, ultimately producing carbon dioxide and water. About half of the carbon dioxide is then recirculated back to gasify the coal to coal gas to continue the process.
"We can continuously operate the fuel cell without the problem of carbon deposition," said Liu, who is also co-director of Georgia Tech's Center for Innovative Fuel Cell and Battery Technologies.
The researchers also evaluated the use of propane to power solid oxide fuel cells using the new anode system. Because oxidation of the hydrogen in the propane produces water, no additional water vapor had to be added, and the system operated successfully for a period of time similar to the coal gas system.
Solid oxide fuel cells operate most efficiently at temperatures above 850 degrees Celsius, and much less carbon is deposited at higher temperatures. However, those operating temperatures require fabrication from special materials that are expensive – and prevent solid oxide fuel cells from being cost-effective for many applications.
Reducing the operating temperatures is a research goal, because dropping temperatures to 700 or 750 degrees Celsius would allow the use of much less expensive components for interconnects and other important components. However, until development of the self-cleaning process, reducing the operating temperature meant worsening the coking problem.
"Reducing the operating temperature significantly by eliminating the problem of carbon deposition could make these solid oxide fuel cells economically competitive," Liu said.
Fuel cells powered by coal gas still produce carbon dioxide, but in a much purer form than the stack gases leaving traditional coal-fired power plants. That would make capturing the carbon dioxide for sequestration less expensive by eliminating large-scale separation and purification steps, Liu noted.
The researchers have so far tested their process for a hundred hours, and saw no evidence of carbon build-up. _PO
The problem with making the removal of CO2 a priority, is that it destroys whatever profitability exists within the coal energy sector. But destroying coal energy production has always been one of President Obama's long-term goals, as he confessed to supporters in San Francisco before being elected in 2008. When so much of the government of the world's only superpower is dedicated to the destruction of reliable forms of energy such as coal, nuclear, oil sands, unconventional gas, offshore oil, etc etc, it becomes difficult for industry and commerce to survive. Since the prosperity and power of the world's only superpower is based upon its industrial and commercial might, it appears that the Obama administration is committing democide and a grand scale, via its broad policies of energy starvation.
Images transplanted from an earlier posting at AFE
Al Fin-
ReplyDeleteYou make many intelligent observations. Your ranting against Obama is too strong. He is probably doing a batter job than Bu$h jr. although that is not saying much.
Nevertheless, I expect another 20-year-long global economic growth cycle, as soon as we stumble out of this recession.
In the USA, we will blunder towards a cleaner and more prosperous future. The two parties are in the way, but they have been in the way for a long time, and we still move forward.
Benjamin: I agree that Obama is doing a "batter job" on the US economy, in the sense that it is growing more badly battered by the day. It is not certain how much more battering it can take.
ReplyDeleteYou remind me of a government employee or an academic in terms of the magical thinking displayed toward the economy: "Somehow we will stumble out of this recession and it will be all better..."
Not likely, when virtually every policy employed by the Obama administration makes it more difficult to start new businesses, employ new people, or expand operations sustainably. When government debt is expanding exponentially, and no one in government has the will to take the necessary machete to the throat of the beast.
The ongoing dumbing down of public education and higher education is leading to some interesting points of view. Everyone is welcome to his own opinion, of course. But not to his own facts.
al fin,
ReplyDeleteI agree with you that it is getting more battered by the day, but to leave that straight at the doorstep of the obama administration is unwarranted, I think.
To tell the truth, I think there are structural issues deep inside our system that are tearing it apart; I believe that these structural, systemic issues far proceeded obama - and even bush and clinton, the first bush, hell - every president back to Reagan.
That's where it starts, IMO. Reagan and/or Carter. Carter, by defining an absurd energy policy that said no to nuclear. Reagan, by making us addicted to deficits and deficit spending, and increasing the ownership gap in this country by an order of magnitude.
After those two, all it has been is our infrastructure and policy playing itself out with ineffectual policiies and dismal demographics. Bush II sped up the process with a poor choice in wars (he could have taken the mandate from 9/11 and used it to get us off foreign oil in the first place, for example). Obama as just let the ossified system sink in to the bone.
Hell, we could maybe go back even further - the disastrous war in vietnam gave us a cultural war, fractional politics, and a very bad case of NIMBY which has slowed everything down. And a very small, unnoticed decision by the AEC in favoring breeder reactors over MSRs has basically put us 40 years behind schedule for energy independence - albeit we would be a *lot* further than we are now if it wasn't for this disastrous NIMBYism as noted above.
So yes, obama is no picnic, but frankly, I'm not sure that any one president could save the US from the rot that it finds itself trapped in. It's way too easy for political opportunists of both stripes to take aim at anything controversial, as a result, our policy on lots of things is not having a policy. And that is a disaster for us all.
Edward: Certainly there is plenty of blame to go around, all the way back to F. Roosevelt and W. Wilson. But this blog is not a history lesson or a course in political philosophy or political economics. And a president is not responsible for what Congress does or doesn't do, or for what all of his predecessors have done for many decades.
ReplyDeleteObama is a discontinuity, a singularity of sorts whose administration is setting itself apart as a destructive force of incalculable and unprecedented magnitude. The fallout from this gang of delinquent vandals could not have been set in motion at a worse time.
Better nuclear power oriented more toward the civilian energy sector rather than the military weapons sector, would have helped a lot -- starting in the 1950s under Eisenhower. But Obama's NRC under anti-nuclear activist Jaczko is setting nuclear energy back decades which the US cannot spare.
Obama's concerted effort to shut down coal plants, coal mines, shale gas, Canadian oil sands imports to the US, offshore oil, and efforts to impede development of other hydrocarbon and energy resources set this gang of jokers on a pedestal of shame all its own.