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Hi, I have a concept which I would like to develop into a working technology, but since I'm not an engineer, I would appreciate any views/comments/criticisms from more knowledgeable people.

-The goal is to make a concentrating solar energy (CSE) platform that succeeds in torrefying biomass, and, in a next step, couples to a gasifier which gasifies part of the torrefied biomass to power a pelletisation plant which turns the torrefied material into pellets.

-It is important to note that the CSE platform is not used for the production of electricity; its thermal energy is only used for the torrefaction process.

Torrefaction is a process of drying which goes through several stages (see diagram of the concept). You can either use a gas to dry and roast the biomass, or you can use a pipe containing a thermal fluid (oil, water).

I would be using a combination of a pipe (as in CSP plants), and recycled hot gas from the torrefaction/gasification steps (see diagram 'recycled gas'). Alternatively torrefaction gas is used in the gasifier. Or both: torrefaction gas goes both ways. Whatever is most efficient.

I would want to tweak the system in such a way that the solar heated fluid enters 'containers' of chipped biomass at each step of the torrefaction process. Temperatures and residence times for each stage differ, so that should be taken into account in designing the plant.

After the biomass has gone through all the stages, the thermal fluid circulates back to the beginning to start the process all over again for a next batch of chips.

The torrefied biomass at the end of the process is a dry, brown powder. This powder will then be pelletised. To power the pellet plant, part of the torrefaction product will be used in a gasifier.

That's it. The end product are torrefied biomass pellets.

I would want to design the plant in as small a scale as possible (so as to use it in rural settings, close to the source of the biomass).

The advantages of this concept are, I think, manifold. First, the advantages of the end product, compared with raw biomass (pellets/briquettes/chips):

-torrefied pellets can be stored for a very long time and do not degrade, because they are hydrophobic; this is very important from a logistical point of view, because it means the pellets become independent of seasonal biomass flows (this contrasts with first generation, non-torrefied pellets which suffer under seasonal flows)

-they have a far higher energy density than ordinary biomass pellets

-therefor they can be transported over much longer distances (the literature suggests the distances can be squared), which is very important from the perspective of biomass logistics and supply chains

-torrefied biomass pellets burn much cleaner than first-generation pellets

-the pellet production is easier and more efficient than starting from raw biomass, because the torrefied biomass is hot when it enters the pelletiser

-torrefied pellets can replace *all* coal in existing power plants; first gen pellets or chips can only be co-fired at rates of up to 15 percent (in IGCCs)

-torrefied biomass pellets can be pulverised in existing coal pulverisers, without modifications; this is very important since ordinary biomass needs dedicated equipment, which drives up costs.


The benefits of using solar heat is that you do not need an outside energy source and that it is highly efficient. It should be low cost too (e.g. instead of using parabolic troughs, one could use "extra flat concentrators", which are far less costly).

Comments about feasibility/efficiency/costs welcome, and all other help would be much appreciated. Please keep in mind: I'm not an engineer.

You can always contact me at solartorrefaction@yahoo.com

Thank you.

Last edited by Louise; 08/02/08 06:55 PM.
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Originally Posted By: Louise
Hi, I have a concept which I would like to develop into a working technology, but since I'm not an engineer, I would appreciate any views/comments/criticisms from more knowledgeable people. .........etc...> ............>


Originally Posted By: Mike Kremer


I will not go into the exact details as to how you obtain the extra heat to completely dry the chips, as I feel that would present problems. Requiring seperate and specialised knowledge,
in 'torrefaction' and gasification?
High temperature drying is obviously required if you really need to produce a powder

When drying wood chips, their resins will excrete and clump the the chips together. You will need to scrape them off the belt, and from each other. Especially if you intend to fine powder the result....mixed...with/for, a fluidised coal powdered power plant?
Thats hardly a small scale job?
Producing the amount of fine powder needed to inject into a fluidised Coal power station, which entails breaking up and grinding the wood chip mass into a fully mixed powder, seems like a full scale industrial process. Requiring adequate wood chips from forest resources.

Using shaped pellets similar to the coal pellets that some power stations use, would be easier from your point of view.?

You state="I would want to design the plant in as small a scale as possible" (so as to use it in rural settings, close to the source of the biomass).

To help fuel a Coal plant you would need to truck in wood chips from miles around, or from lumber mills? Hardly a local rural enterprise?

You jut might be better off just producing lage briquettes for home furnace users? You certainly would'nt need to dry the chips out so much as you would to produce powder. As you would not need to grind the chip mass into a powder (save on processing)

Sorry I hav'nt got a lot more to say, nice grafics though.



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"You will never find a real Human being - Even in a mirror." ....Mike Kremer.


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Hi Mike, thank you for your comment, but I think you do not understand the concept. Perhaps I haven't explained it well.



The goal is to torrefy biomass. You do this by heating it to 200-300 °C, in separate stages and in a low-oxygen environment. The result of this roasting process is a dry biomass that is easily crumbled into a powder.

This powder, or the small granular pieces will then, on-site, be pelletized (just like you would pelletize non-torrefied biomass).

The pellets can then be shipped over much larger distances than ordinary biomass pellets. And they can be used in coal-fired power stations.

Currently, torrefaction relies on heat that is most often obtained from a fossil fuel source. I want to skip that step, and use heat from solar concentrators.


You know those solar cookers and solar ovens, right? You can cook biomass in these. But the temperatures obtained by these low-cost, simple solar cookers is not high enough (150-200 °C max). Solar concentrators such as the ones used in CSP plants can reach much higher temperatures.

So I want to use these concentrators, heat a thermal fluid (like oil) and use this heat to roast the biomass. Torrefaction is roasting. It's not pyrolysis. The only byproduct is a low-energy gas, no tars or liquids. You can drive off the gas, and reuse it.

See the short overview of the process.

Last edited by Louise; 08/03/08 08:17 PM.
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Greetings,

I for one think this is an outstanding idea Louise. I like to think of these combined uses of ‘alternative cross technologies’ as getting twice the bang for the buck. For instance, besides Your ingenious concept of combining solar and biomass technologies, another group is attempting to incorporate solar tech in the towers of wind turbines.

It appears Your design’s impeding limitation is current technology or more specifically the application. If current “simple solar cookers are not high enough (150-200 °C max)”, insufficient for the “200-300 °C” goal, then the key appears to be applying twice the heat. I believe the Mohave solar plant P.G. & E built utilizes heated oil at 140 °C. If current solar tech can apply a twofold magnification from new, more efficient panel advances or heated viscosity transfer methods, then it would match the targeted temp of 280 °C (=/-).

On the West coast of the United States, there are many small ‘co-generation’ plants that ‘fire’ the biomass with natural gas burners. With Your approval, I would like to forward Your idea to the South Lake Tahoe authorities in charge of initiating a biomass plant here in California. There is a great need to manage forest fires here, and some were concerned where the thousands of tons of brush and over growth where to be disposed of. What better place than a “solar cooker”, I think they are going to like the idea!

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Anonymous, thanks for your positive reception of the idea.

However, keep in mind that existing solar concentrating panels (like the ones used in CSP plants) can easily reach the required temperatures (more than 300 °C). It is these panels I'm looking at (like parabolic troughs or extra flat concentrators).

The panels in the following pictures easily heat oil or water to above 300 °C:


Parabolic troughs.

Extra flat concentrator - is cheaper.


Very cheap solar cookers are not up to the job, whereas solar furnaces are for solar-chemical work, at very high temps.


Solar cooker: 100-150 °C.


Experimental solar furnace in France: 2000 - 5000 °C - way too high.


In short, I am only looking at using concentrators like the ones in the first two pics. CSP-style concentrators.

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I believe You are looking at a solar thermal plant like this one, no?



This is the company that partnered with Pacific, Gas and Electric in the Mohave desert. Check out the website for details and let Me know what You think, Mike

<A HREF="http://www.solel.com/products/pgeneration/ls2/">Solel - Leading the World in Solar Thermal Energy - Solar Thermal Power Generation</A>


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For those interested, here is another good example of crossing alternative enrgy technologies. It uses wind turbines with ocean tidal turbines.



Full article: http://www.scienceagogo.com/news/20060819023800data_trunc_sys.shtml

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Correction: I should have typed: "here is another good example of crossing alternative enrgy technologies if they use wind turbines with ocean tidal turbines."

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Originally Posted By: Anonymous
I believe You are looking at a solar thermal plant like this one, no?



This is the company that partnered with Pacific, Gas and Electric in the Mohave desert. Check out the website for details and let Me know what You think, Mike

<A HREF="http://www.solel.com/products/pgeneration/ls2/">Solel - Leading the World in Solar Thermal Energy - Solar Thermal Power Generation</A>



Yes indeed, but as you can see from my small sketch, I don't need the super heaters, steam generators, turbines, generators and cooling tower.

In my idea, the hot oil in the tubes would be used directly the roast the biomass, in different stages.

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Im not a expert on the process you are attempting here , but I
couldnt help to notice a few things.

the illustration you provided appears to show 7 rows of 7 solar collectors which each can provide 300 C temperature to a liquid.

you could probably boil off a olympic sized swimming pool every minute with that array.

my point here is ( what is the intended end product).

energy?

or a way to use more energy to produce less energy?

I know that if you are trying to get funding from any of the
availiable government funding programs they will not fund anything that truly makes sence or through its process does not use more than it puts out.

thats just the pig headed way that they opperate due to the taxes they get from gasoline sales.

you have a good idea here , and hot liquid expands and when hot liquid expands it gets hotter because of the added pressure from expansion , if the liquid is a contained liquid.

I suppose that this pellet to coal fired plants would be a good way to switch the current 50% of americas energy consumption to bio fuels.

I just cant understand why we dont just use water through the solar array and turn a steam turbine.

that way our food supplies would not become entangled in the energy market.























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Isn't the point here to utilize waste materials (wood, cellulosic biomass, manure, or whatever) to carbonize it
and capture the offgassing and bio-oils, and create a substitute for coal.

The extra energy and raw materials (oils for plastics, fuels, etc.) are just by by-products and not meant to be maximized.
This principle also sequesters carbon, or is neutral in the long run.

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everybody is always thinking carbon.

2/3 of water is hydrogen , it falls from the sky , free of charge!!!

lately it falls more often than usual. LOL

in order to concern ourselves about Carbon we must first burn a hydrocarbon fuel that emits carbon di-oxide.

hydrogen does not emit.

it just combines with oxygen to form water again.

I'll bet there is more energy in a pellet sized volume of water than there is in a pellet , if you take into consideration the energy expelled making and shipping the pellet.

as I said when a liquid is heated it expands , if it is contained it cannot expand as much and will pressurize the gasses in its container , water can be seperated into hydrogen and oxygen using pressures , and using a spark or a heat source
they can be re-combined to produce heat.

if the pressures that accomplished the splitting was caused by solar radiation then the fuel itself is free , just like the rain , and the oxygen.

and if you have to add a little pressure to split the water then that too can be free , you already have pressurized hot water to work the hydraulics with.

I know this can be done , the trouble is getting others to believe it can be done , others that could finance your project.







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When some one invents a free source of Hydrogen, thermal, solar or electrical, let me know, so I can start looking for a new career.

Torrified wood pellets would be a great addition to fuel sources, especially home heating. Current wood pellets must be kept dry, are hard to store and can degrade. Torrified pellets, if made correctly could prove to be an easier fuel for conversion from home heating oil to biomass. Two things I would keep in mind are, ash content (no bark in whole tree chips), and how sturdy the pellets become (can they be moved by blowers, not conveyors).

The most important part is scale, current pellet mills are around 100,000 tons per year in size. This results in 7000 tractor truck loads of chips per year, which could be quite a disturbance for a small town, roads, general infrastructure. The question of sustainability arises as well, forest here in the northeast can produce 1 ton of biomass per year, per acre. That means you would need 100,000 acres, close by.

I would suggest looking at a factor of 4 or 10 smaller. This would require at most 25,000 acres.

Having researched torrification a bit, I think you will find that you primary energy need is in drying. As you start to reach temps capable of torrification, the reactions become exothermic and releases heat.

In short, the need for high temperature process heat is low, the need for low quality drying heat is high. This may drive you thinking and calculations. This could mean, for example, a combination of different types of solar collectors could be used. Purpose built, and closely coupled to only one section of the process line.

I love the idea, and hope more people pursue upgraded biomass fuels. There are many of us that would design systems around them, if available.
Cheers,
Trevor



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Quote:
When some one invents a free source of Hydrogen, thermal, solar or electrical, let me know, so I can start looking for a new career.


1) a solar cell , with leads.

2) two test tubes.

3) a bowl of energy ( water )

4) and sunlight.

its already been done.
free hydrogen and free oxygen as long as the sun shines.

= free energy

about looking for a new career dont be in such a big hurry !

this stuff has been around for decades , probably before you began your career.

its just that it cant be bought and sold , its not a product yet.

because a way hasnt been found to make it a product due to the fact that it just keeps falling in the form of rain and sunshine
believe me they are trying their best to make it a product however by heating the atmosphere to the point that solar radiation will be not as frequent , due to all of the vapor clouds , and they are getting very close to accomplishing this.

as soon as the climate gets so bad that they have to pump sunshine to us , then it will be a sellable product , then they will sell the sunshine and rain as a fuel source.








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you mean like this vapor that stops sunshine from reaching a solar pannel or collector?

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Originally Posted By: paul
Im not a expert on the process you are attempting here , but I
couldnt help to notice a few things.

the illustration you provided appears to show 7 rows of 7 solar collectors which each can provide 300 C temperature to a liquid.

you could probably boil off a olympic sized swimming pool every minute with that array.


Thanks Paul for your comments.

The sketch is just an illustration of the basic concept. Obviously the precise amount of solar collectors for the different process steps still has to be studied.

But in order to be commercially viable, you probably need a rather large array, and lots of biomass.


Originally Posted By: paul
my point here is ( what is the intended end product).

energy?

or a way to use more energy to produce less energy?


The goal is to densify biomass and preprocess it into a superior product, so that it can replace coal.

Ordinary biomass densification concepts (e.g. first generation pelletisation) do not succeed very well in this context. Torrefaction has a large number of key advantages.


Originally Posted By: paul
I know that if you are trying to get funding from any of the availiable government funding programs they will not fund anything that truly makes sence or through its process does not use more than it puts out.

thats just the pig headed way that they opperate due to the taxes they get from gasoline sales.


Mm, I'm not really interested in government funding. Just exploring a concept. If investors are interested, that's obviously welcome.



Originally Posted By: paul
you have a good idea here , and hot liquid expands and when hot liquid expands it gets hotter because of the added pressure from expansion , if the liquid is a contained liquid.

I suppose that this pellet to coal fired plants would be a good way to switch the current 50% of americas energy consumption to bio fuels.


I think liquid biofuels (e.g. cellulosic ethanol or synthetic biofuels) are not the most optimal use of biomass in the grand context of energy for transport.

I see a bigger future in the use of biomass for the production of power and heat - and in electric cars that use this electricity.

Moreover, later on one could couple biomass power plants (or coal plants that switch to torrefied biomass pellets), to CCS, and go carbon-negative.


Originally Posted By: paul
I just cant understand why we dont just use water through the solar array and turn a steam turbine.

that way our food supplies would not become entangled in the energy market.


You can of course use a traditional CSP concept to generate electricity. But for the moment it's rather expensive and there's no good energy storage technology.

Biomass is stored solar energy. That's the main advantage. It is also the most competitive of all renewables. But in order to make it compete directly with coal, there is a need for better logistics and densification technologies. And it's on this latter point that my concept would elaborate.

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Originally Posted By: Anonymous
Isn't the point here to utilize waste materials (wood, cellulosic biomass, manure, or whatever) to carbonize it
and capture the offgassing and bio-oils, and create a substitute for coal.

The extra energy and raw materials (oils for plastics, fuels, etc.) are just by by-products and not meant to be maximized.
This principle also sequesters carbon, or is neutral in the long run.


Exactly. That's the whole idea. You understand it. Maybe I wasn't succinct or clear enough in my opening post, because several people do not seem to understand the idea.

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Originally Posted By: Anonymous

Torrified wood pellets would be a great addition to fuel sources, especially home heating. Current wood pellets must be kept dry, are hard to store and can degrade. Torrified pellets, if made correctly could prove to be an easier fuel for conversion from home heating oil to biomass.


Sure, torrefied pellets would transform all the current biomass logistics considerably. That includes the use of pellets in home heating systems.

Like you say: torrefied biomass pellets are hydrophobic and can thus be stored much easier.


Originally Posted By: Anonymous

Two things I would keep in mind are, ash content (no bark in whole tree chips), and how sturdy the pellets become (can they be moved by blowers, not conveyors).


Thanks, that's indeed an important point, but I haven't looked into biomass feedstocks all that deeply yet. However, many non-woody feedstocks would qualify, I think.

I'm sure there have been lots of studies into the chemical composition of different types of biomass.

Originally Posted By: Anonymous

The most important part is scale, current pellet mills are around 100,000 tons per year in size. This results in 7000 tractor truck loads of chips per year, which could be quite a disturbance for a small town, roads, general infrastructure. The question of sustainability arises as well, forest here in the northeast can produce 1 ton of biomass per year, per acre. That means you would need 100,000 acres, close by.

I would suggest looking at a factor of 4 or 10 smaller. This would require at most 25,000 acres.


Yes, I'm looking into more small-scale systems. Going smaller might mean giving up some scale-advantages. But I hope that the solar-concentrating element in the concept, offsets these losses and makes small-scale integrated systems competitive.

Originally Posted By: Anonymous

Having researched torrification a bit, I think you will find that you primary energy need is in drying. As you start to reach temps capable of torrification, the reactions become exothermic and releases heat.

In short, the need for high temperature process heat is low, the need for low quality drying heat is high. This may drive you thinking and calculations. This could mean, for example, a combination of different types of solar collectors could be used. Purpose built, and closely coupled to only one section of the process line.


Thanks for the great advice. I will certainly be looking into combining different solar concentrators for the different steps of the process.


Originally Posted By: Anonymous

I love the idea, and hope more people pursue upgraded biomass fuels. There are many of us that would design systems around them, if available.
Cheers,
Trevor


Thanks for the encouragement, Trevor. I'm glad you like the basic outlines of my idea.

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Louise
your illustration below does not allow for fluid expansion , have
you considered including an expansion chamber / tank or are you intending to utilize the additional pressures that would proportionately increase with the increasing temperatures?

pipes burst if their material strenghts are overcome by the liquid contained in them , they also get longer , and very hot oil squirting on someone could cut them in half.

keep these things in mind in a closed loop such as the one below.



as I said before I think its a good idea to switch the current
50% of our energy consumption from coal fired power plants to the pellet fired plants as you have indicated , only you still need sunshine for this to work , the U.S. needs a stable fuel to switch to Im sure you can agree to that , have you did any research into the possibilities of a lowered solar irradiance level indication in the last few years?

and any forcast as to the levels in the future?

as these would make or break any stable feasibility of this/your concept.



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Originally Posted By: paul
Louise
your illustration below does not allow for fluid expansion , have
you considered including an expansion chamber / tank or are you intending to utilize the additional pressures that would proportionately increase with the increasing temperatures?

pipes burst if their material strenghts are overcome by the liquid contained in them , they also get longer , and very hot oil squirting on someone could cut them in half.

keep these things in mind in a closed loop such as the one below.


Yes, good point, as said, I'm not an engineer. So if ever I get to work on the idea in a serious manner, I'm sure the final configuration will take into account the problems related to the pressures of the heating fluid.

Originally Posted By: paul
as I said before I think its a good idea to switch the current
50% of our energy consumption from coal fired power plants to the pellet fired plants as you have indicated , only you still need sunshine for this to work , the U.S. needs a stable fuel to switch to Im sure you can agree to that , have you did any research into the possibilities of a lowered solar irradiance level indication in the last few years?

and any forcast as to the levels in the future?

as these would make or break any stable feasibility of this/your concept.


The concept is meant for use in the tropics and the subtropics, where the waste biomass resource is very large.

My country of preference (because I have studied it most in depth) is India, where several hundred million tonnes of waste biomass are available each year. There's also a critical coal shortage in India, which is projected to persist over the coming years.

Solar insolation is very good in India. Working with concentrating mirrors should work there:


I'm also looking at sub-Saharan Africa. E.g. Namibia - a very sunny place - has millions of hectares of acacia bush available, which have to be cleared because they are considered a national catastrophy.

Solar concentrators would obviously work very well there too.

I think that all across the tropics and sub-tropics, there would be enough sunshine to make the concept feasible.


The advantage of torrefied biomass pellets is that they can be transported (exported) over very long distances, because their energy density is much higher compared to non-torrefied pellets.

Last edited by Louise; 08/15/08 02:24 PM.
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Hi again Louise & Co.,

Here are some links for Biomass,

Biomass Energy Home Page Biomass Energy
http://egov.oregon.gov/ENERGY/RENEW/Biomass/BiomassHome.shtml

Oregon D.O.E. - Resources for Inventors
http://egov.oregon.gov/ENERGY/CONS/BUS/invent_resource.shtml

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Solar energy is available around the world and for cutting down your electricity bills; this is the right option for you. The advantage of getting solar electricity is that it does not produce any pollutants and further it is renewable. Solar energy is available in plenty and you need a simple kit which will convert the heat of solar energy into electricity that will stored in a battery and whenever we require electricity we get it delivered from battery.
For more information visit: http://www.lincenergy.us

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