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What plants might be grown, just for bio-fuel?


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Someone wrote about an American plant Gopher Weed on these forums some time ago. i can't find the post.

Apparently you can just turn that sstraight into usable (CO2 producing?) oil.

 

Just googled "Gopher weed" and came up with this

New York Times

Sunday, May 27, 2007

Published: January 3, 1981

 

Within five years, the University of Arizona will be turning tons of desert plants into oil, gasoline and petrochemicals, preparing for the day when plant-produced oil will supply 5 to 10 percent of the nation's energy needs, a researcher at the school says.

 

Jack Johnson, the school's director of Arid Lands Studies, says plant-produced oil could be filling that role within 10 to 15 years. He also predicts that a 40-acre Arizona biofuels research facility, now being developed near the Tucson International Airport, will put the university in the forefront of biofuels development.

 

Biofuels are fuels derived from a wide variety of renewable resources, such as plants, algae and refuse. ''There is no other facility like this in the U.S.,'' Mr. Johnson said. ''The university is already the unquestioned leader in the development of energy from biofuels. We're the only ones doing research at this level.'' Operational by 1990

 

About 20 acres of the site already are in use, and the university hopes to have the site fully operational in 10 years.

. . .

The facility will include about 10 acres outdoors, and another 3,000 square feet of greenhouse space for growing plants such as jojoba, buffalo gourd, guayule and gopher weed to process into oil.

 

UNIVERSITY PREPARES TO GROW OIL - New York Times

 

but this is the :turtle: article that inspired me to start this thread

Kentucky.com | 05/27/2007 | Tiny seeds from Northwest could a be source of biofuel

Tiny seeds from Northwest could a be source of biofuel

PLANT THOUGHT ABLE TO PRODUCE MORE OIL FOR LESS MONEY

By Les Blumenthal

MCCLATCHY NEWSPAPERS

 

WASHINGTON --

A plant that flourished in Europe roughly 3,500 years ago could become a major source of biofuel.

 

Researchers say that camelina, planted on millions of acres of marginal farmland from eastern Washington state to North Dakota, could help power the nation's drive for cleaner energy.

 

"This is the most exciting crop I have seen in my 30-some years in this field," said Steven Guy, a professor . . .

. . .

Camelina supporters say the plant can grow in more arid conditions, doesn't require extensive use of expensive fertilizers, herbicides and pesticides, and can produce more oil from its seeds than other crops such as canola, by some estimates, for half the price.

 

"We actually think it might be the next wonder crop," said Tom Todaro, the chief executive of Targeted Growth, a Seattle biotech firm that's working to increase camelina yields "radically." The company hopes to produce enough seed to plant 1 million acres of camelina by 2009.

 

About 85 percent of the feedstock used in biodiesel in the United States comes from soybeans

MSU Extension in Roosevelt County

Article

 

Montana Camelina 2005 (Provided by Duane Johnson, MSU Northwestern Agricultual Research Center)

Introduction

 

Camelina is an ancient crop first known to be cultivated in Northern Europe during the Bronze Age.

The seeds were collected, crushed and boiled in water and the oil that was derived was used as a lamp oil, a medicinal treatment and as an edible oil. Camelina, Camelina sativa L., is native to northern Europe from Finland to Romania and east to the Ural Mountains.

Camelina fell into disfavor when more productive crops such as wheat and canola began to be produced.

Farm subsidy programs supporting commodity crop severely reduced camelina production. It became a common weed in Europe known as false flax (contaminating flax fields) and as Gold-of-Pleasure. Camelina cultivation has been strengthened recently as demand for omega 3 oils has increased dramatically.

. . .

Within the past year, the US Food and Drug Administration has allowed health claims to be made for omega 3 oils. Omega 3s are known to primarily reduce inflammation in humans.

. . .

. . .Domestic fish, fed primarily from non-omega 3-rich feeds, frequently lack measurable amounts of omega 3.

. . .

The superior crops, however, are flax, hemp, perilla and camelina. . .

. . .

Perilla is a new crop without a great deal of agronomic research. It is a crop more common to China than the US.

. . .

The seed are exceedingly small at 345,000-465,000 per pound

Roosevelt County Extension Office - Ag Article

 

drawing and first Camelina link courtesy of care 2

Tiny seeds from Northwest could a be sou... - Care2 News Network

I have tried to post a few photos of the plant from Google Image search but can't anyone know why?

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In the Minneapolis Star Tribune March 18, 2007 they did an article about Cellulosic Biomass. Reprint of article here:Hill and Tillman Article

 

The net gain is very small for corn, but better from soybeans.

 

They also have been studying native prairie plants and a mixture of different types of plants out-produce both corn and soy per acre. The biggest problem right now is a limited supply of seed to re-establish the prairie plants.

 

Heres a good article on what they found:

Farm & Ranch Guide: North Dakota's Ag Newspaper

 

I think this idea builds upon a better foundation for biofuels. It decreases the competition for food stuffs, it enhances the environment, and I have reservations about using more exotics. There is most likely native plants in each region that would result in an equal/nearly equal output.

 

I worry that introducing another 'weed' into a region that has alternatives defeats some of the effort. Its not like corn escapes into the wild and drive out other species, a fight that is apparent in several states including Minnesota with purple loosestrife and a yellow weed that is out-competing native prairie in Teddy Rosevelt park in N. Dakota.

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Do you call the ethanol from sugar cane bio-fuel? It is becoming an increasingly common fuel with buses in my area.

Yes a lot of petrol stations have a10% ethanol mix (from CSR). Some people are very down on biofuels.

i think because fuel made from heavily subsidised US crops like corn is not economic

I don't think that is the case with sugar cane but i don't know for sure

 

Howard does not tax the ethonol as much as straight gas(38c a litre +GST on top of that. It is a very inflationary tax when you live in a continent where everything is 1,000K from everything else)

 

the Germans are investing in the biggest bio-energy (methane) digester in the world.

You would think that the Germans, being German, would have it all sorted before spending money

Growing Crops for Fuel: Thanksgiving in the Gas Tank - International - SPIEGEL ONLINE - News

 

They are already the ? largest producer of solar panels in the world

 

Hopefully a title that might come to Australian scientists with their new Sliver (not a typo) Cell Tecnology.

If they can solve mass production method problems. it looks tricky (show was on "Catalyst" might still be on ABC on -line)

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I'm sure that anything that grows can be used as a bio-fuel since it contains carbon that can be oxidized; the question is what plants are most efficient at providing the fuel we want - either oil for bio-diesel or cellulose for ethanol? In terms of pure efficiency, I suspect that an algae will be the best source of feedstock; unfortunately, there are some issues that need to be addressed - scaling of bioreactors, algae strains and market development. (Google algaculture [i'm not allowed to paste links, yet])

 

Then, there are some crops that are in the research or ramp-up phase of marketing - one I know of is hazelnut (see Badgersett dot com)

 

From my perspective, a crop that is planted once is best for the environment. Also, such crops can be bred for production - albeit at a slower pace than annuals due to reproductive rates. However, due to the fact that algae has a limited structure and certain strains already produce up to 50% oil, I don't think that any terrestrial plant will ever come close to the output that algae can achieve - so there will be places where algae is the better choice.

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Elephant Dung Helps Scientists Develop New Biofuel

 

Scientists in the Netherlands have discovered a fungus in elephant dung that will help them break down fibres and wood into biofuel.

Planet Ark - Elephant Dung Helps Scientists Develop New Biofuel

I love this story

Here you have all these scientists poking around in elephant poo

Terrific!

It is a joy and wonder that such people exist

Reminds me of the Hero of the film "The Gods Must Be crazy" one of the funniest movies of all time (made in S. Africa)

 

It also shows the importance of pure research.

Collecting knowledge for knowledge's sake rather than to solve a problem or make money.

 

Some recent articles on the subject

 

What's the Best Biofuel? Researchers Found Out

Study results revealed that, compared with gasoline and diesel, ethanol and biodiesel reduced greenhouse gas emissions by nearly 40%, reed canarygrass by 85%, and switchgrass & hybrid poplar by about 115%.

Green Car Congress: Researchers Evaluate Greenhouse Gas Reductions from Different Cropping Systems

 

Palm Oil: The Biofuel of the Future Driving An Ecological Disaster

environment.guardian.co.uk

The numbers are damning. Within 15 years 98% of the rainforests of Indonesia and Malaysia will be gone, little more than a footnote in history. With them will disappear some of the world's most important wildlife species, victims of the rapacious destruction. . .

conservationists believe the move to clear land for this "green fuel" is often little more than a conspiracy

Palm oil: the biofuel of the future driving an ecological disaster now | Energy | Guardian Unlimited Environment

 

Deadly Nut Tapped as Biofuel Source

On a large tract of land in Thailand's dusty northeast, Suwit Yotongyot hopes to make a fortune on jatropha, a plant with a poisonous nut that might hold the key to the nation's energy troubles.. . .

The nuts are more than 30 percent oil, which burns with a clear flame, producing a fraction of the emissions of traditional diesel. As a bonus, the oil can be used in simple diesel engines without refining, just by mixing it with fuel.. . .

bushes are easy to grow, start producing nuts quickly, and are resistant to drought

Discovery Channel :: News - Earth :: Deadly Nut Tapped as Biofuel Source

Clean Coal, Forest Biofuel and Other Fairy Tales

- earthmeanders.blogspot.com

Two of the biggest, most dangerous lies about global warming are that clean coal exists and the world's forests are adequate to provide biofuel. Dirty coal and industrial forest harvest for energy only speed up the planet's ecosystem's destruction. . . .

The world's forests have been hammered for millennia; and are barely able to continue

Earth Meanders: Clean Coal, Forest Biofuel and Other Fairy Tales
Wild flowers could provide a solution to global warming

IAN JOHNSTON ENVIRONMENT CORRESPONDENT

WILD flowers grown on some of the world's least fertile land could provide huge amounts of environmentally friendly biofuel, according to US scientists.

 

Research has found the naturally occurring mix of plants on the American prairie provide more than twice as much energy as the corn or soybean crops that have previously been considered as sources of biofuel.. . .The native perennial grasses and flowering plants provide a much better environment for wildlife than a monocrop plantation and converting them into biofuel actually reduces the amount of carbon in the atmosphere while the standard fuel crops add a small amount.

Scotsman.com News - International - Wild flowers could provide a solution to global warming

 

Will Sweet Potatoes Give You Gas?

sustainablog.blogspot.com

Of course, I'm talking about biofuel -- what were you thinking? Anyway, biopact takes note of the planned development of a integrated biogas-ethanol plant in the African nation of Guyana that would use sweet potatoes, cassava and rice residue as the feeds

sustainablog: Will Sweet Potatoes Give You Gas?

Ethanol More Energy Efficient Than Thought

news.nationalgeographic.com

A new study now suggests that the most important biofuel—ethanol, which is made from corn in the United States—is more energy efficient than previously thought.

Ethanol More Energy Efficient Than Thought, Study Says
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Someone wrote about an American plant Gopher Weed on these forums some time ago. i can't find the post.

Apparently you can just turn that sstraight into usable (CO2 producing?) oil.

Gopher weed (I think it’s the sativa variety of Camelina) sounds like a cool plant – able to grow productively in poor soil and climate, a high-quality, healthy food-grade oil-producing plant.

 

As to the question “What plants might be grown, just for bio-fuel?”, I suspect this could be any of them, or none. All of the food-grade vegi oils (including corn oil) filtered properly to remove solids, make good pure oil fuels. Perhaps there is one that doesn’t taste good enough for food, or is unpopular for health reasons (like palm oil), so would be valuable only as a fuel, but I’ve never heard of it, and have no reason to suspect that the best plant fuel oils aren’t also good food oils. A near bit of tech trivia is that Rudolf Diesel’s first engines were designed to run on peanut oil (a nice, low-viscosity oil), then modified to use petro-based kerosene because the latter was (and still is) cheaper to produce (source: Vegetable oil used as fuel - Wikipedia, the free encyclopedia).

 

Though it’s not quite true that any diesel engine and fuel system can easily be modified to run on pure vegetable oil, many of them can, and there are a number of mature systems, companies, and user communities existent now – see Straight vegetable oil as diesel fuel: Journey to Forever. No ethanol, gasoline, or other additives or refining processes are required – though good filters, fuel line heating, and other elaborations are.

 

AFAIK, the big drawback with vegi oil as a fuel now is not engine system design, fuel distribution, etc, but cost. As of 2007, the average cost of vegetable oil in the US – sold as a food - is $10.28/gallon. The stuff is about as energy-dense as petro-diesel, which currently has a average US cost of $3.803/gallon. Not a huge difference – about 270% - but enough to keep businesses and ordinary consumers from flocking to it, even if the capability to produce it in large quantities existed.

 

Waste vegi oil – popular because it can be had essentially for free from restaurants, which currently have to pay to have the nasty stuff carted off – takes a good bit of refinement, involving separating, pH adjusting, and other complicated and energy-expensive stuff. There’ll never be enough WVO available for large-scale needs, though, only for the niche market that exists while demand for SVO and bio-diesel is tiny.

 

The main challenge presented in the use of plant oil as a petro-fuel replacement, as best I can see, is production. Consider the following, based on the goal of America becoming fuel-self sufficient through the near 100% replacement of petroleum with plant oils:

Doing the math, we find that, for the US to grow enough plant oil using all of its farmland (ignoring the need to grow food) to meet 100% of its current oil needs, requires a productivity of about 335 gallons/acre/year, a rate reached only by palmseed. Palmseed and coconut, the 2 top-producers, are tropical plants, however, not effectively growable in the US (former rainforest apparently is ideal palmseed-growing land). The best US-growable crop appears to be peanut, at 113 gallons/acre/year.

 

At first glance, the goal of America becoming fuel-self sufficient through the near 100% replacement of petroleum with plant oils appears unachievable. Some refinements to the data make it look a bit more feasible:

  • Only about 50% of current petroleum use could not practically be replaced by other fuels and energy sources. What’s left are primarily vehicles, which require an easy-to-handle, portable fuel.
  • Vehicle fuel efficiency is currently at historic lows. It’s reasonable to assume that, as part of an industry-wide shift to specialized plant-oil-burning diesel engines (or even better systems – closed-cycle steam, perhaps?), efficiency could be about doubled.

Taking this into account, the required production rate becomes about 85 gallons/acre/year. In principle, then, the US could become completely renewable oil based with about 705,000,000 acres of continuously producing peanut.

 

It’s a close call, however, and ignores issues like emissions. I’ve heard accounts that plant oil combustion bi-products are in some areas cleaner than petroleum, but think that, for approximation purposed, they’re about the same as present-day diesel, worse than present-day gasoline. For CO2 emission, I believe essentially all carbon-based fuels are roughly equivalent

 

When considering possibilities for large-scale oil production, one rather disturbing possibility can’t be ignored. The oceans, we know well, are rich sources of plant energy. Until the mid 19th century, US demand for oil – about 15,000,000 gallons/year, primarily for lamps and machine lubricants - supporting a thriving industry based on an efficient natural converter of aquatic plants to high-quality, readily obtainable and refinable oil – whales. (source: ”How the Oil Industry Saved the Whales”)

 

Using modern techniques to increase breeding rates and weed-out undesirable wild traits – essentially domesticating oil whales – it’s conceivable that a renewable oil supply exceeding than any land-based agriculture could be created. Personally, I cringe at the though of an industry based on the wholesale slaughter of vast numbers of intelligent animals, and hope this outlandish (I can’t recall having heard it before this post) possibility is never realized. :eek:

 

Yeah solar. :cheer:

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At first glance, the goal of America becoming fuel-self sufficient through the near 100% replacement of petroleum with plant oils appears unachievable.

I tend to agree.

Especially if you read these alarming statistics from Tim Flannery.

in

"The Weather Makers" that

in 1997 the world used the equivalent of 422 years of fossil sunlight.

(p77)

and

6 billion people are using four times as much energy as their grandfathers 100 years before.

and

"If humans were to look to biomass as a . . .replacement, we would need to increase our consumption of all primary production on land by 50%"

(p78)

and

between 1800 and 1980 humans produced 244 petajoules of energy.From 1980-99 humans produced 117 petajoules

About half of the total emitted over the previous 180 years)

(p79)

and

". . .half of the energy generated since the Industrial Revolution has been consumed in just the last 20 years"

(p167) say since the first cotton mill in 1733?

 

Vietnam Biocarburant Company: production of gas oil containing jatropha curcas

In 2005, Vietnam had to import 7,93 million tons of gasoline and of oil, that is to say 92% of the national needs. The success in the production of gas oil bio containing seeds of jatropha curcas contributes to lower the imported volume of the fuels and to protect the environment.

The Institute of tropical biology obtained successes in the experimental production of gas oil containing seeds of jatropha curcas, opening a new orientation of investment for industry and agriculture Vietnameses.

"By 2050, the world could face a serious energy crisis, because of the insufficiency of the renewable resources.

Therefore, the green fuel has interested considerable scientists and investors in the United States, in Germany, in China and in India ", pointed out Thai Xuân Of, a person in charge for the Institute of tropical biology, while underlining the asset of its discovery.

The jatropha curcas is a robust plant originating in India perfectly adapted to the climatic conditions of Vietnam and particularly to the arid grounds of the Center.

In India, the objective laid down by its government is to produce 40 million tons of gas oil at base of seeds of this plant, it explained.

Courrier du Vietnam

(+ babel fish)

Tubang-bakod

Jatropha curcas

PURGING NUT TREE, BIG-PURGE NUT

Tubang bakod / Jatropha curcas / PURGING NUT TREE, BIG-PURGE NUT: Philippine Alternative Medicine / Medicinal Herbs / StuartXchange

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Where y'all going wit all dat milo!!?? Sorghum that is; sweet sorghum.

Mind you I don't know squat about it yet, but I had some in my bird-feed mix and decided to plant it as I planted the black-oil sunflower from the mix & it sprouted. Anyway, I got a mess o' milo planted, but I have no idea what variety. Nonetheless, sweet sorghum is mentioned as bio-fuel worthy here:CHAPTER VII SORGHUM: Post-harvest Operations

Certain varieties of sorghum are characterised by the production of high levels of sugar in the stalk. These are known as sweet sorghums and attempts have been made to commercialise their production in the USA, Argentina and Brazil for the extraction of juice for the preparation of sugar syrup for alcohol production by fermentation.

 

I recall years ago a Nebraska farmer I was visiting gave me a bag of milo and told me it would pop like popcorn. It never worked for me, but maybe the moisture content has to be a certain level. Say...did you know milo (sorghum) is the 5th most grown cereal grain in the world!?? It tops corn! Wish me luck! :ideamaybenot:

 

sorghum

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Here’s my not-extensively researched and vetted, “executive summary” of plant-based renewable combustion fuels, with petroleum fuels and hydrogen for comparison:

  • All dry plant matter is mostly (C6H10O5)n – cellulose – and lignin, a family of big, complicated molecules consisting of roughly the ratio of elements C20H16O5.
  • Plant oils are triglyceride such as C55H98O6 – similar to typical diesel fuel, C12H26, but with a bit of oxygen here and there – though much less than in their plant precursors. For all intents and purposes, plant oil is chemically indistinguishable from animal oil – rendered fat.
  • Ethanol is C2H6O6, making it an alcohol – something roughly following the formula CnH2n+2O. Way less carbon than any of the above, and much more oxygen.

From this, we see that:

  • Plant oils require much less energy to make than Alcohols – basically just crush, press, and filter a plant, and you get usable oil. Alternately, and much less efficiently, you can feed them to animals, then render the animals for their oil. Alcohol takes a lot of chemical transformation to produce.
  • Like light petroleum gasses (CH4 methane, C3H8 propane, etc.), alcohol has less carbon in it, so is cleaner burning.

All of these fuels are essentially hydrogen delivery systems. Each has advantages and disadvantages:

  • Plant oils are require little energy to produce, are easy to store and handle, but produce a lot of carbon when burnt
  • Alcohol requires more energy to produce, is also easy to store and handle, but produces less carbon
  • Petroleum gasses require the least energy to produce (just find them, tap them, transport them, etc) but aren’t liquids, so are harder to store and handle, and, of course, aren’t renewable. They also produce little carbon when burned.
  • Liquid petroleum likewise requires little energy to produce and isn’t renewable, is easy to store and handle, but produces a lot of carbon.
  • Hydrogen requires all of the energy it contains, and then some, to produce, as bad as some alcohol producing processes, is about the hardest fuel in the universe to store and handle, but produces no carbon when burned.

Though many plants are good oil suppliers, as Journey to Forever’s nice tables show, their per-acre productivity varies widely, with palm seed oil more than twice as productive as the nearest competition, and over 30 time as productive as a low-scoring plant, such as corn.

 

So that’s the rundown. It’s surprising, to me, how similar fuels of various kinds actually are, explaining perhaps why no single fuel offers an obvious “silver bullet” solution to the world’s energy needs.

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[*]Hydrogen requires all of the energy it contains, and then some, to produce, as bad as some alcohol producing processes, is about the hardest fuel in the universe to store and handle, but produces no carbon when burned.

 

What about H2 and CH4 produced during pyrolysis, Craig?

It's easy to produce, but I'm not sure about collection and storage.

In any case, it seems to be ideal.

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Hydrogen requires all of the energy it contains, and then some, to produce, as bad as some alcohol producing processes, is about the hardest fuel in the universe to store and handle, but produces no carbon when burned.
What about H2 and CH4 produced during pyrolysis, Craig?

It's easy to produce, but I'm not sure about collection and storage.

In any case, it seems to be ideal.

AFAIK, hydrogen, CH4 (methane), and other “reformed” fuel gases are made from more massive hydrocarbon molecule fuels, and have no more energy than these source fuels. I’m only familiar with CH4 -> H hydrogen reformers - a few years ago, a friend of mine was interested in a GE’s home fuel cell, a heavily subsidized program involving a refrigerator-sized, hydrogen fuel cell producing about 2000 W when supplied with residential natural gas (mostly CH4). I understand that such reformers can be about 80% efficient (though they produce CO waste gas, an especially dangerous gas to get near a PEM fuel cell).

 

Other hydrogen reformer that was big news a few years ago were ones that allowed medium size consumer electronics – PCs, mostly – to be powered by small PEM or anode/cathode fuel cells with hydrogen supplies by methanol, or other hydrogen-carrying liquids, like sodium borohydride. This Inforworld article describes such a system, producing about 20 W for 3 to 4 hours from a pen-sized replaceable fuel cartridge costing about US $1.50.

 

Though reformed hydrogen systems have a lot of useful applications, I don’t think they’re very promising for “heavy” power system needs, such as vehicles, residential and industrial heating and cooling, and electric power generation. From a practical engineering perspective, if you have a hydrogen-carrying liquid such as alcohol where you need power, it’s easiest and most efficient to just burn it, rather than reforming it into hydrogen and burning the hydrogen or using it in a fuel cell.

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AFAIK, hydrogen, CH4 (methane), and other “reformed” fuel gases are made from more massive hydrocarbon molecule fuels, and have no more energy than these source fuels.

 

What do you mean by this? H2 and CH4 are produced naturally through the pyrolysis. I guess the "reformed" part is throwing me off. :hihi:

 

Another example is the conversion of sawdust or waste wood into bio-oil for the production of electricity or syngas, using a fixed fluidized bed pyrolyzer from Dynamotive.

 

In many industrial applications the process is done under pressure and at operating temperatures above 430°C (806°F). Anhydrous pyrolysis can also be used to produce liquid fuel similar to diesel from solid biomass or plastics [1]. The most common technique uses very low residence times (<2 seconds) and high heating rates using a temperature between 350-500 °C and is called either fast or flash pyrolysis.

Pyrolysis - Wikipedia, the free encyclopedia

BioOil’s potential use as a fossil fuel replacement is already well established. Customers for BioOil can include local, regional and national electrical utilities and power producers operating with partial or complete fuel substitution depending on scale and application. The opportunities for industrial applications are too numerous to list but some immediate applications in primary industry are kilns and boilers in pulp and paper, process heat in boilers in sawmills, metallurgy, oil and gas industries, as well as in secondary industries such as greenhouses, district heating and stationary engines.

 

Pyrolysis fuels have a very complex chemical composition, containing a multitude of different compounds. The specialty applications of these compounds in industrial processes and manufacturing are just beginning to be explored. They represent a potentially very large market for value-added products derived from BioOil.

Dynamotive Energy Systems | The Evolution of Energy

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AFAIK, hydrogen, CH4 (methane), and other “reformed” fuel gases are made from more massive hydrocarbon molecule fuels, and have no more energy than these source fuels.
What do you mean by this? H2 and CH4 are produced naturally through the pyrolysis. I guess the "reformed" part is throwing me off. :confused:
Hydrogen reforming refers specifically to the process of extracting hydrogen (and, as a by-product, CO) from methane (CH4) by adding water and heat – it’s thus commonly termed “steam reforming”, and is how most hydrogen gas is currently produced. I was generalizing the term a bit – perhaps inappropriately – to refer to any process that creates one fuel from another.

 

In this more general sense, pyrolysis – the simplest form of which I’m aware consists of simply capping a large mass of organic waste and using the resulting methane at the pressure the system produces – is a reforming process. Like many practical fuel reforming schemes, the added energy – heat - needed for the reaction is supplied by the source fuel itself. A famous, small-scale system of this kind was one promoted by the PRC government for rural use, in which the waste manure from a single household produced cooking and lighting gas for the house.

 

Burning the methane produced by this, or any pyrolysis system, produces less energy than burning the feed fuel (manure, etc.), but is much cleaner burning, and easier to deliver to burners, lamp mantles, fuel cells, etc.

 

Fuel from biomass seems a very good solution for situations where large biomasses are available and there’s a need for gas fuel, but gas fuels aren’t ideal for all applications. In particular, they’re not ideal for vehicles. And, as with other renewable fuel schemes, I’m unsure if sufficient biomass exists, and whether facilities to gasify it can feasibly be made, to 100% replace the power needs currently satisfied by fossil fuels.

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Thank you, Craig, for elucidating.

 

I also have strong doubts that biofuel technology can replace current consumption. Nonetheless, it has the potential to create a major deficit in atmospheric carbon.

I know little to nothing of the tech behind fuel cells, but I have read that they can be built to be as safe as traditional fuel tanks. (from the book Natural Capitalism)

 

If I find the book I'll post an excerpt.

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I know little to nothing of the tech behind fuel cells, but I have read that they can be built to be as safe as traditional fuel tanks.
The major issue with various kinds of fuel cells (the term is a bit of a misnomer, as these devices are not containers for fuel, but generators of electricity that take fuel consisting of hydrogen and oxygen, and produce waste heat and water) is not safety – they and fuel containers they require have existed since the 19th century, been used without major incident in most manned spaceflight (with the exception of Apollo 13, which suffered a crippling explosion in one of its 2 oxygen tanks due to wiring that had been unknowingly damaged prior to launch, not anything related to its fuel cells) – but energy density. Compared to petroleum and alcohol-burning motors and their fuel systems, fuel cell-electric motor and their traditional fuel systems weigh 3 or more times as much. (the 4/2007 Scientific American article “Gassing Up with Hydrogen” (subscription or purchase requires for full article text) has a good discussion of these issue)

 

From an emissions perpective, hydrogen fuel cells are wonderful. The Apollo missions used their fuel cell exhausts for the crew’s water supply – it was nearly completely pure.

 

Another very major obstacle with fuel cells is cost. Currently, they cost about US $5/watt, about 3-6 times the cost of a diesel-powered electric generator. The sort of low-mass systems best suited for application such as vehicles cost about $10/watt for the fuel cell alone, ignoring the cost of the fuel storage and other systems. For comparison purposes, note that 1 horsepower equals 750 watts. A typical lawnmower engine (3.5 HP, or 2625 W), would thus currently cost about $26,250 for a fuel cell equivalent – though this comparison is likely somewhat exaggerated, as such systems would almost certainly use hybrid battery systems (like those used in current hybrid autos) to reduce the required power of the fuel cell.

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Thanks for the link on energy density. The table comparing different storage types was enlightening.

 

I think the problem with energy density could be worked around with some cleaver engineering (perhaps wrap-around fuel tanks that take advantage of unused space), but it seems that the current cost of fuel cells is the biggest prohibitive factor with hydrogen technology. Do you know if the fuel cells cost so much because of supply/demand economics or is it a technology/costly materials issue? Or both?

 

We've already been discussing the possible dangers to the environment (of which I'm not convinced of one bit), but what are the other hurdles for this technology?

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