Biofuels from pyrolysis of wood waste

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SteveW's picture
SteveW
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Biofuels from pyrolysis of wood waste

Today's DD article about hydrogenation of the oily residue from pyrolysis of wood waste was interesting research and a continuation of work that has been ongoing since at least the early 90's and is likely to be the focus of research by major oil companies. http://www.rnw.nl/english/article/dutch-breakthrough-bio-fuel-technology.

This reminded me of the story of black liquor which came to prominence last year. Black liquor is a by product of the kraft pulp process which separates the cellulose from wood into the wood pulp leaving a thick black oily mess of lignin, hemicelluloses and the chemicals used in the pulping process. This black liquor can be combusted so that modern pulp mills are net energy producers. Last year US mills realised that their black liquor fuel, if cut with diesel (which had never been previously used), would qualify them for a tax credit incentive designed to reduce fossil fuels for transportation. http://www.bloomberg.com/apps/news?pid=newsarchive&sid=abDjfGgdumh4 Typical of the law of unintended consquences this $6 billion tax break put Canadian kraft producers at a crippling disadvantage so Canada introduced enviro grants. http://thetyee.ca/Blogs/TheHook/Labour-Industry/2009/06/17/BlackLiquor/

So black liquor is an already existing waste by product from a major industrial process. A Swedish company has patented a gasification process for black liquor that is capable of producing liquid transportation fuel and has built two plants, one at a US kraft mill and the other at a Swedish kraft mill. http://www.biomassmagazine.com/article.jsp?article_id=2818&q=&page=all http://www.chemrec.se/Chemrec-plants.aspx 

With all the dead pine beetle killed trees in BC (which many attribute the the recent mild winters since the mid-80's) we need to develop a process for fermenting the wood cellulose to ethanol and converting the remaining waste by gasification of black liquor. It makes more sense than shipping 500 tons a day of wood chips to thermal plants in Europe for their green credits. http://www.theglobeandmail.com/news/national/british-columbia/bc-wood-pellets-a-green-hit-in-europe-but-not-alberta/article1679202/?cmpid=rss1

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Jager06
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Re: Biofuels from pyrolysis of wood waste

Why the added steps? If you are going to cull the forest of its infested trees, you simply pyrolize the wood itself. The net result would be far more energy in the form of gasification (including transport and harvest EROEI) than if you were to try to reduce the wood to the kraft pulp byproduct to only utilize that byproduct.

You could even get the equipment doing the operation to run entirely off the wood being harvested, no dino fuels whatsoever. And still have a net gain on energy, without increasing greenhouse gas or any other harmful material. The trees have sequestered the gas metabolically, will do so again when the remaining living trees re metabolize the byproduct of the burn.

Some videos to demonstrate how simple and straightforward this is.

http://www.metacafe.com/watch/3493748/wood_gas_truck/

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yobob1
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Re: Biofuels from pyrolysis of wood waste

Why not cut out the middleman altogether?

During the Second World War, almost every motorised vehicle in continental Europe was converted to use firewood.

Wood gas cars (also known as producer gas cars) are a not-so-elegant but surprisingly efficient and ecological alternative to their petrol (gasoline) cousins, whilst their range is comparable to that of electric cars.

http://www.lowtechmagazine.com/2010/01/wood-gas-cars.html

 

I'm not really sure converting wood to vehicle fuel can escape the laws of thermodynamics and provide more enrgy than it takes to make the fuel.

I love it when the term "biomass" is used.  Locally they're trying to get a biomass electrical generation plant.  Folks what were talking about is burning wood to make electricity.  Not only is the pollution a problem, but it just doesn't make sense.  If it did the power companies would be chomping at the bit to build them - they're not.

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Jager06
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Re: Biofuels from pyrolysis of wood waste

We have a power generation plant in our area that uses wood chips from the local sawmill. Very cool.

The amount of energy produced through gasification, when the smoke is run through 2000 deg F carbob bed filter is more than if the wod were to be burned alone. There is more energy released from wood gas if you use propane to heat the wood than from the propane.

The problem arises form the varying pyrolisis points of different types and densities of biomass. The difference between pine and cedar, cornhusk and oak, lawn clippings etc are enought o cause brudging thermal variation inside the burn chamber with a stratified downdraft gasification system.

I will be looking for specific math on the efficiencies, and report back here if/ when I can find it.

Yobob....did you see the video fo the guy with the old F-150 using the gasifier from plans out of Mother Earth News? Thats what initially got my attention with this technology.

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yobob1
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Re: Biofuels from pyrolysis of wood waste
Jager06 wrote:

We have a power generation plant in our area that uses wood chips from the local sawmill. Very cool.

The amount of energy produced through gasification, when the smoke is run through 2000 deg F carbob bed filter is more than if the wod were to be burned alone. There is more energy released from wood gas if you use propane to heat the wood than from the propane.

 

Yobob....did you see the video fo the guy with the old F-150 using the gasifier from plans out of Mother Earth News? Thats what initially got my attention with this technology.

That may well be true.  However when you consider the amount of energy that went into harvesting and delivering that wood, I'm prety sure you will find a net energy loss.  Ther si no free lunch when it comes to energy.

As to your sawmill /power plant - that's been a farily common practice and makes more sense in that you're using the waste from the wood already delivered - those typically have been done to power the sawmill.  The biomass plant they're proposing here is not associated with a sawmill so all of the wood would have to be harvested and brought to the plant.  Assuming the plant is going to consume more wood than can be grown as a replacement, you find that harvesting must take place further and further away form the plant as time goes on.

I find most of these schemes do exactly what they set out to do - fleece a bunch of people and taxpayers to enrich the folks selling the equipment.

SteveW's picture
SteveW
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Re: Biofuels from pyrolysis of wood waste
yobob1 wrote:

Why not cut out the middleman altogether?

During the Second World War, almost every motorised vehicle in continental Europe was converted to use firewood.

Wood gas cars (also known as producer gas cars) are a not-so-elegant but surprisingly efficient and ecological alternative to their petrol (gasoline) cousins, whilst their range is comparable to that of electric cars.

http://www.lowtechmagazine.com/2010/01/wood-gas-cars.html

LOL. The car on the left hand side doesn't seem to be of WWII vintage. Are you sure that's legal? A range comparable to electric cars...and then you chop down the neighbourhood trees?

But seriously my main point, which I guess was lost among all my commentary, was that an existing industrial by-product can be used to make liquid motor fuel instead of its current use, generating electricity for the grid. I know the American usage of "gas" for the liquid people put in their cars can lead to semantic confusion.

I believe Germany never used those wood-gas cars in WWII since they produced motor and aircraft fuels from coal. While the Fischer–Tropsch Synthesis is not economical in an era of cheap oil there must be some cross-over point that would apply to any carbonaceous feedstock. This economic data should be available from that WWII experience. The Chemrec corporate website also has an economic analysis paper (of 260 pages) but since I am neither a Chemical Engineer nor an Economist I cannot read it critically.

 

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Zapata
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Posts: 28
Re: Biofuels from pyrolysis of wood waste

Still, this method is taking carbon, neatly sequestered, and emitting it into the atmosphere.

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