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Author Topic: Can biomass and sunlight work together to fuel our future?  (Read 3415 times)

Offline peppercorn

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Here's my scheme:

  • Solar concentrators heat oil to ~280degC. The oil heats an insulated vessel containing batches of woody biomass in a low oxygen atmosphere, leading to torrefaction.
  • The torrefied wood is then ground evenly to 200μm particle size, but needing only 15% of the grinding energy compared with air-dried wood.
  • The ground torrefied wood is then further heated to ~450degC by separating a small part of the product to power a furnace.
  • At this temperature the condensates and aromatics are driven off (to be recovered or burnt) leaving mainly amorphous carbon.
  • Once compressed this carbon can be transported efficiently and used in a number of chemical or energy applications.

As a power source this carbon product makes an excellent primer for syngas generation to be used in stationary or marine engines.


 

Offline jeniferi87

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Can biomass and sunlight work together to fuel our future?
« Reply #1 on: 20/08/2010 08:18:58 »
- I shared this thread on my hi5 group !
Regards
 

Offline John09

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Can biomass and sunlight work together to fuel our future?
« Reply #2 on: 20/08/2010 09:20:50 »
I came here for updating my knowledge and yeah I'm getting so.
 

Offline Mazurka

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Can biomass and sunlight work together to fuel our future?
« Reply #3 on: 20/08/2010 16:43:53 »
Sorry, I had missed this.

A number of biomass (specifically waste wood) pyrolysis plants have recently been proposed at various locations within the UK - "Sunrise Renewables" has got planning consent for 9MW plants in Barrow-in-Furness, Hull and Barry in South Wales. 

These plants chip feedstock before drying (using heat from gas engine exhaust) to 10% moisture prior to grinding to <5mm then fed to the pyrolyser to produce the syngas, subsequently utilised (after cooling) by a gas engine.  For some reason, the documents state that if the feedstock is too small it does not produce gas so efficiently. (I guess the fuel bed tends to clump as the volatiles come out)

I would be interested to see whether a 2 stage system as you proposed was anymore efficient.  I would add that although this is a Combined Heat and Power Plant, there is still excess heat to do the drying or potential first stage torrefaction.

Feel free to message me if you want to look at the documents submitted for planning permission for the plant in Barrow (it is all public information, just slightly difficult to find!)
 
 

Offline peppercorn

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Can biomass and sunlight work together to fuel our future?
« Reply #4 on: 22/08/2010 19:12:26 »
"Sunrise Renewables" has got planning consent for 9MW plants in Barrow-in-Furness, Hull and Barry in South Wales.  These plants chip feedstock before drying to 10% moisture prior to grinding to <5mm then fed to the pyrolyser to produce the syngas, subsequently utilised by a gas engine. 
I would be interested to see whether a 2 stage system as you proposed was anymore efficient.  I would add that although this is a Combined Heat and Power Plant, there is still excess heat to do the drying or potential first stage torrefaction.
Thanks for your response, Mazurka.
I really only considered my idea having worth in Temperate regions (lots of sun) where plenty of fast growing renewable forest could be harvested. The 'product' (hopefully almost pure carbon) only becomes economical (compared with raw wood - even well dried wood) when there is an intensive to transport this secondary commodity quite some distance before use.  The idea being that the lions share of the energy content is still in the carbon/charcoal whilst being far lighter and compact to move about (by road, say) and arrives as an easily malleable 'fuel' at the end point - a bit like the hydrogen economy model, only a solid.

Feel free to message me if you want to look at the documents submitted for planning permission for the plant in Barrow (it is all public information, just slightly difficult to find!)
I won't at the moment, Mazurka, as I don't think what 'Sunrise' are doing is of particular baring to my process, but I sincerely appreciate the offer.
 

As a simple model for 2nd-world areas to use - the product should allow a scaling up of 'old-tech' methods of smelting iron without the need for coke or poorly manufactured charcoal.
 

Offline Mazurka

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Can biomass and sunlight work together to fuel our future?
« Reply #5 on: 23/08/2010 12:10:09 »
No problem, I understand where you are coming from.
It strikes me as a good a good technique for something like eucalyptus plantations, an oft cited biomass crop (around 10T per ha per year) which are too full of oil to be of used directly as a fuel.

Mind you it still amazes me that hemp is still overlooked as a biomass crop - it grows like a weed in most places, the seeds can be processed for oil, the stalks have a lot of cellulose to process into alcohol or used for clothing fibres etc.

 
 

Offline peppercorn

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Can biomass and sunlight work together to fuel our future?
« Reply #6 on: 23/08/2010 12:57:53 »
It strikes me as a good a good technique for something like eucalyptus plantations, an oft cited biomass crop (around 10T per ha per year) which are too full of oil to be of used directly as a fuel.

Mind you it still amazes me that hemp is still overlooked as a biomass crop - it grows like a weed in most places, the seeds can be processed for oil, the stalks have a lot of cellulose to process into alcohol or used for clothing fibres etc.

Thanks Mazurka. Those are indeed sources to consider.
I think the thing i like about a 'solid-carbon' economic model is, as you imply, the source of C becomes less of a concern.  Oily, woody, stalk-like, etc - all biomass can be reduced to something resembling charcoal.  Obviously some are more suited than others, but nature gives us a low-cost route to carbon, often on land that is too poor to efficiently harvest food-crops.

I saw this article recently:
http://www.newscientist.com/article/dn19308-the-next-best-thing-to-oil.html
Quote
The same technology [that generates hydrogen from a combination of sunlight and steam] can also be used to split CO2 the resulting CO can be combined with the hydrogen to form hydrocarbon fuel

Now this is all very well and good, but these devices require fairly exotic materials and, I'm expecting ongoing calibration and maintenance.  For Hydrogen alone they are an exiting route towards a H2 economy and an interesting feedstock for liquid fuels in the interim.  But why waste the technology making carbon-monoxide?   Even in the Californian desert where these solar chemical plants are being trialled there could be a way to make a dry-carbon process work with, say hydroponics (with closed lossless water cycle).
 

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Can biomass and sunlight work together to fuel our future?
« Reply #6 on: 23/08/2010 12:57:53 »

 

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