Wood gas production using pellets (discussian)

[Dune]

Could'nt decide whether to post this is the Green room or here, but it involes pellets so here it is.

In my long quest to design the most practical residential co-gen system possible, I find myself in the pellet room.

The many advantages of pellets are mostly obvious, the biggest two being the ability to readily feed from a hopper, and the apparant fact that softwood pellets are as good or better than hardwoods. Softwood being a key to my imediate interest since in most of the Northeast it has less than no value unless trucked in high volume.

Gasification of wood to produce fuel for internal combustion engines is a well established technology at this time.
The use of wood pellets for fuel simplifys and improves this process a great deal acording to my musings and research.

By using the waste heat from the cooling system of the wood gas fueled generater engine (gas or diesel) along with the electricity created, extremely high efficieny of fuel use could be acheived.

The downside from my perspective is the cost of the pellets. As a firewood scrounger Pellets are the same as any other heating fuel I don't use; they cost money.

The cost is acutaly much higher than the bag price too, since it is taxed money.

Therefore, the only way this meets all my criteria is if I can produce my own pellets. I have searched the subject on this forum and wonder if there are users of these machines that can offer experience. Espescialy of intereset of course would be homeowner scale machines. All other thoughts are of course welcome as well.

 

[smwilliamson]

John is this you? If so, call me again. Your number didn't register in my phone cause the batteries were dead. If this isn't you. Call if you want and we'll become good friends :cheese:

 

[Dune]

Yeah Scott, just me. Wondering if any one wants to talk about Co-Gen and making pellets.

 

[smwilliamson]

yeah, I'll bite. Today I measured the exhaust from my garage heater. 167 °F . How much of this can I reclaim for other uses.

 

[Dune]

yeah, I'll bite. Today I measured the exhaust from my garage heater. 167 °F . How much of this can I reclaim for other uses.

None. I am talking about something like this http://www.stakproperties.com/index.php?p=3_23

 

[jtakeman]

Dune,

Not sure of your total plan. More info on the unit that will gasify the fuel would help. Like how well it will handle the waste ash?

Do you have access to loads of clean saw dust? Otherwise I would look into field grasses and leaf's as the main source of fuel. You can pelletize them just as you would a wood pellet. They will produce more ash than a clean saw dust pellet. But about the same as a standard pellet(One that is made from a dirty source of wood waste). A standard grade wood pellet or utility pellet is what most biomass plants use. Clean wood fiber is more expensive and harder to get a hold off.

If you need more info on the other pellet? Check this thread:

https://www.hearth.com/econtent/index.php/forums/viewthread/50637/

The guy that made ours is on this forum and loves taking pellets. His name is DJ. I am sure he would love you to visit his place and see his process. His mill is more for large scale production, But the process is very much the same!

Love to hear the total plan!

 

[smwilliamson]

yeah, I'll bite. Today I measured the exhaust from my garage heater. 167 °F . How much of this can I reclaim for other uses.

None. I am talking about something like this http://www.stakproperties.com/index.php?p=3_23

you mean this: ;-P
http://victorygasifier.com/

 

[Dune]

Yeah, same idea. Didn't my link work? I couldn't see where the victory system is made. U.S.A.? The idea is, you use a water cooled generator, fueled by a gasifier. Using a heat exchanger, the heat from the engine coolant 180 F, heats your home. If you generate enough electricity during the process of heating your home in the winter, you have no electric bill all year, under net metering. The reason switch grass doesn't appeal to me is I have no way to produce it. Pine is free around here.

 

[smwilliamson]

You can grow enough goldenrod on 10 acres to make this work and havervest twice a year.

 

[smwilliamson]

Victory is from Washington State. There is a bulding at the UNiversity of Florida that uses his system to run part of the campus.

 

[jtakeman]

The reason switch grass doesn't appeal to me is I have no way to produce it. Pine is free around here.

I wasn't talking switch grass. Regular old lawn clippings or timothy grass from any field. But you got free pine. Dust I hope?

I have a couple of contacts that have the smaller mills. Most are not impressed with them. The china units wear the dies out quickly. But you probably knew that already!

out!

 

[Dune]

The reason switch grass doesn't appeal to me is I have no way to produce it. Pine is free around here.

I wasn't talking switch grass. Regular old lawn clippings or timothy grass from any field. But you got free pine. Dust I hope?

I have a couple of contacts that have the smaller mills. Most are not impressed with them. The china units wear the dies out quickly. But you probably knew that already!

out!

Got to slow down and read more thoroughly. LEAVES! Like oak leaves? They would certainly be easier to make into pellets than pine logs. I imagine you would need one serious pile to make a years worth. I asume this is proven or you wouldn't mention it. Ash really isn't a problem for gassifiers if you are burning pellets, because even a crappy pellet is beter than dirty wood chips.

Dust? no. I would also need some kind of grinder or whatever. Leaves would be cheaper than buying a grinder, I am sure. And no, I don't want to buy a machine from China. I would make my own first.

 

[jtakeman]

The reason switch grass doesn't appeal to me is I have no way to produce it. Pine is free around here.

I wasn't talking switch grass. Regular old lawn clippings or timothy grass from any field. But you got free pine. Dust I hope?

I have a couple of contacts that have the smaller mills. Most are not impressed with them. The china units wear the dies out quickly. But you probably knew that already!

out!

Got to slow down and read more thoroughly. LEAVES! Like oak leaves? They would certainly be easier to make into pellets than pine logs. I imagine you would need one serious pile to make a years worth. I asume this is proven or you wouldn't mention it. Ash really isn't a problem for gassifiers if you are burning pellets, because even a crappy pellet is beter than dirty wood chips.

Dust? no. I would also need some kind of grinder or whatever. Leaves would be cheaper than buying a grinder, I am sure. And no, I don't want to buy a machine from China. I would make my own first.

Leaves, Shreaded paper(from many local business), Lawn clippings and saw dust wouldn't require chipping and then hammer milling. Free dust is all I would mess with as far as wood. Lawn clippings would be the easier to pelletize along with saw dust. Leaves and Paper have to be chopped or run thru a leaf shreader to assist in the pellet process.

Another plus with gassifier is the moisture content should not be an issue. You should get more gas from a wet pellet than a dry one.

 

[Dune]

Another plus with gassifier is the moisture content should not be an issue. You should get more gas from a wet pellet than a dry one.[/quote]

Exactly. One of the other major benefits of pellets over other products for gassifying. This would also reduce the amount of ash, since you are burning less fuel.

 

[briansol]

You can have my leaves free of chrage every year if you rake 'em

 

[smwilliamson]

I suppose the downside is the producer gas itself. It is very difficult to store in large quantities. Because of this, isn't the system in requirement of a superintendent?

 

[Dune]

I suppose the downside is the producer gas itself. It is very difficult to store in large quantities. Because of this, isn't the system in requirement of a superintendent?

My intent would never be to store the gas. It is mostly carbon monoxide and other nasty stuff. A typical system would be lit, then when gas starts flowing, the internal combustion engine (generator motor) would be started. The engine would then run till the gassifier ran out of fuel. That is another reason pellets would be great. An auger could fill the hopper of the gasifier so you could have a long burn without needing a giant hopper. Interestingly, the output of the gassifier is regulated by the engine directly.
The intake of the engine causes the draft of the gassifier.

An effient system would still involve storage though. The electric company would store the electricity till you need it. Probably a good idea to have thermal storage as well (water tank) so you don't have to run the Generator engine continuously. Run it, charge the storage tank, spin your meter backwards, sleep, start over tomorow.

 

[Dune]

Another plus with gassifier is the moisture content should not be an issue. You should get more gas from a wet pellet than a dry one.[/quote]

Sorry, T-Jakeman, I did it again. I was working in the shop, and typing in between welds.

Actualy, I was thinking the oposite, that the dryness of the bagged pellets would be an advantage. Scott told me the other day that the moisture content is about 3%.
That was what got me thinking about gassifying them. Way back in the old days (preWWII) there was a theory espoused that injecting water into the base of the gassifier fire in just the right amount would produce "water gas" hydrogen and oxygen, for a net gain in power. I personaly don't believe this to be true, under the "you can't
get something for nothing" theory, also known as the first law of thermodynamics. I beleive that while you may be able to create water gas during pyrolysis, you will pay for it by using more pellets, to create the heat needed to crack the water. Kind of like burning wet logs in a woodstove; if you were creating water gas and burning it, you would get a lot of heat from aload of green logs.

 

[Dune]

Ok, I googled pellet machines for a couple hours yesterday and didn't find much at all. Anyone care to contribute a link?