Posted on 03/16/2007 5:52:03 AM PDT by Red Badger
One of the possible configurations of the proposed H2CAR process.
Purdue University chemical engineers have proposed a modification to the conventional biomass- or coal-to-liquids Fischer-Tropsch process that could, by their calculations, produce sufficient fuel for the entire US transportation sector.
Their process, however, relies on an abundant supply of hydrogen—between 239 and 276 billion kilograms of hydrogen per year—to produce 13.8 million barrels of synthetics per day. The new approach—which the researchers call a “hybrid hydrogen-carbon process,” (H2CAR)—proposes co-feeding a gasifier with hydrogen from a carbon-free energy source, such as solar or nuclear power, and CO2 recycled from the syngas (hydrogen and carbon monoxide) conversion reactor.
The H2CAR process offers a number of advantages compared to conventional biomass- or coal-to-liquids technologies according to models the team developed:
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No CO2 is released to the atmosphere or is required to be sequestered as a result of the chemical processing system. When conventional methods are used to convert biomass or coal to liquid fuels, 60% to 70% of the carbon atoms in the starting materials are lost in the process as carbon dioxide whereas no carbon atoms would be lost using H2CAR. *
Approximately 40% of the amount of coal or biomass is needed to deliver the same quantity of liquid fuel. This is advantageous for prolonging the life of the known coal reserves as well as in reducing the land area needed for the bioenergy crop. The land area required to grow the biomass for H2CAR is accordingly less than 40% of that needed by other pathways that solely use biomass to support the entire transportation sector. *
Current estimates suggest that an annual US biomass supply of 1.366 billion tons could produce approximately 30% of the United States transportation fuel with conventional processes. The H2CAR process shows the potential to supply the entire United States transportation sector from that quantity of biomass. *
The synthesized liquid provides H2 storage in an open loop system. The addition of hydrogen atoms to carbon atoms from coal or biomass provides a high-density method for storage of massive quantities of hydrogen. On a carbon atom basis, the energy content of the liquid fuel is higher than that of coal or biomass.
The process is detailed in an open access research paper appearing online this week in the Proceedings of the National Academy of Sciences.
The researchers explain the rationale of using H2 in the H2CAR process by the significantly higher annualized average solar energy conversion efficiency for hydrogen generation versus that for biomass growth.
Land-area and H2 requirement for conventional and process using PHEVs as a function of drivable distance traveled per single full charge H2CAR of batteries. Click to enlarge.
Agrawal argues that the new process also would be more practical than all-electric or hydrogen-powered cars, in part because of the limited storage capacity of batteries and hydrogen storage tanks.
The tremendous convenience provided by the existing infrastructure for delivering and storing today’s fuels is a huge deterrent to introducing technologies that use only batteries or hydrogen alone. A major advantage of our process is that it would enable us to use the current infrastructure and internal combustion engine technology. It is quite attractive for hybrid electric vehicles and plug-in hybrid electric vehicles. —Rakesh Agrawal
Realizing this requires significant research in two areas: finding ways to produce cheap hydrogen from carbon-free sources and developing a new type of gasifier needed for the process.
The proposed H2CAR-based processes also have a strong impact on the future areas of research. The primary research emphasis needs to be on cost-effective H2 production from a carbon-free energy source such as solar or nuclear. In addition, efficient, low-cost, and easy-to-operate methods are needed for the conversion of biomass through reaction with H2 to a suitable hydrocarbon liquid fuel. In the short term, the same is true for the conversion of coal to liquid. The current conversion route of gasification followed by a H2-CO liquid conversion reaction is quite inefficient, and an alternative efficient hydrogenation process is highly desirable.
In the mean time, until such alternate processes are discovered, the preservation of carbon atoms in the current gasification and H2-CO liquid conversion reaction is essential. A proposed solution in this work is to co-feed H2 and recycle CO2 from the H2-CO liquid conversion reactor to the gasifier. Feasibility and development of such gasifiers especially for biomass will require extensive research.
Purdue has filed a patent for the concept. The approach is in the conceptual stages, and a plan for experimental research is in progress.
Resources:
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“Sustainable fuel for the transportation sector”; Rakesh Agrawal; Navneet R. Singh; Fabio H. Ribeiro; W. Nicholas Delgass; PNAS published March 14, 2007, 10.1073/pnas.0609921104
Rest In Peace, old friend, your work is finished.......
If you want on or off the DIESEL "KnOcK" LIST just FReepmail me........
This is a fairly HIGH VOLUME ping list on some days......
KnOcK!!!!!!!!!
Wind and solar energy will/could be used to generate H2 to augment the FT process, so no excess CO2 will be produced. Electrolysis..............
This looks like a way of making fuel X from fuel Y by adding Hydrogen. The only way this would reduce dependance on foreign oil would be if the US had loads of Nuclear power plants to make the hydrogen. Might as well just drill in ANWR.
And why is CO2 important? Anybody?
But the final product still is a hydrocarbon which must be burned, giving off CO2, right?
P.S. Liberals will read "by-products" to mean "pollutants."
Windmills and other renewable electrical energy sources are used to break watr down to hydrogen and oxygen. That is the source of the hydrogen.
>>why is CO2 important?
CO2 is short for COO. And we know who the coo-coos are, right?
Geothermal, such as Yellowstone, or ocean current, such as the Gulf stream can supply the electricity needed for electrolysis. Now if someone could revisit the work of Steve Myers, who apparently discovered the proper resonant frequency of hydrogen needed for super efficient electrolysis, well then we have a program.
We have coal out the wazoo in the US and it's just waiting for us to use. The Coal Mining Unions should be all over this. The FT process is and has been a proven process for nearly a century. This is just a new tweak to make it more "green" and thus more acceptable. The petro-oil equivalent of this amount of fuel would still produce the same amount of CO2
except that this will produce more diesel than a barrel of oil will, which produces less CO2 and gets more mpg..............
Diesel gets more mpg than gasoline, Therefore produces less CO2 per mile driven. The US has coal deposits to last for a couple of centuries or more. A barrel of crude produces only a fraction of itself of diesel. A ton of coal is almost totally capable of being turned into diesel, thus less CO2........
That is a good answer - except that one part of the equation - the 300,000,000 tonnes of Hydrogen - still needs to be found.
But it looks like Texas (for instance) has had a surge in Nuclear generation licensing, so there is hope for releasing the power of America's coal.
Even without the H2 augmentation, the FT process is a good thing. As I have seen on other sites, there are H2 processes being developed that can fill the bill without the need for massive amounts of nuclear or other power sources. But if necessary, the FT process can be used to generate its own H2, kind of like the "Breeder Reactor" nuclear equivalent...........
The future is bright.
A few new generation nuclear plants.
Plasma gassification of garbage (a tecnology that is proven and on the market now), Throw in biomass gassification, some coal gassification, combined with US oil production and we will not need to import a drop of oil.
I hope to see the day when we can ban oil imports. Let Hugo, Mexico with their immigration demands and the Jihadis eat their oil.
This doesn't make any environmental sense from a greenhouse gas perspective. If you draw your control volume around the conversion procdess AND the end-use transportation system and if the HC ratio of the liquid fuel is the same as gasoline, then the the same amount of C is released into the atmosphere as CO2 during combustion as if you were using gasoline. Where's the benefit to reduced global warming (IF such were anthropogenic and caused by CO2)?
CO2 is a "pollutant." Didn't you get the memo last week? You were on the distribution list.
Hmmmmm, yet another source of raw materials....
It is expensive concentrating CO2. Losing CO2 when you are making fuel is like pouring half of your eggs out while making omelets.
It would not take that many more nuclear plants to create the hydrogen needed to fuel the nation, especially if you were using a direct heat method rather than hydrolysis.
Basically you would be making the nations cars nuclear powered.
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