Wood Chip Boiler

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My sister in law's husband runs a BIG chip boiler for a textile manufacturer. He says his actually runs better on chips that are a little less dry. I know that they spent just as much on their storage with live floor as they did on the boiler. it was around 4 million bucks I think.

JP
 
http://www.biomasscenter.org/resource-library/publications

I would suggest looking through these publications. If I had to pick one, the Wood-Chip Heating Systems: a Guide for Institutional and Commercial Biomass Installations" is a good read.

Some general comments about wood chip applications is they do not scale down well. There are a lot of moving parts in the wood feeding system no matter what the size. The chips are non uniform and but usually in roughly 2" chips. If you are moving tons per hours, the chips flow pretty well but if you are try to move small volumes, the chips clump. Wood chips are generally green and wet when delivered. Let them sit too long and they degrade and sometimes catch fire or mold. If you handle them wet, they tend to be a problem in winter where they are right on edge of freezing, its real easy to get to the point where the chips freeze in clumps if the conditions are right. Many of VT installations very quickly had to switch to "premium" wood chips supplied by one or two suppliers at a premium cost as they couldn't handle the standard grade chips. Chips can be very deceiving, from 20' away they look like uniform chips but get closer and you frequently will find buried under the outer layer sticks and staves which can really foul things up.

Most of the small institutional biomass chip installations were heavily subsidized so they could afford to put the system in. The general preference for small institutional or commercial units are pellet boilers. Pellets may be more expensive but the scale down far better than a biomass plant. I have heard second hand from fairly reliable sources that the amount of day to day attention from the plant staff is a lot higher than they were told when the system was built to the point where the staff has to be increased or diverted to deal with wood handling issues.

Another aspect is depending on the size you could get into the EPA boiler MACT regs which is something you really want to avoid
 
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http://www.biomasscenter.org/resource-library/publications

I would suggest looking through these publications. If I had to pick one, the Wood-Chip Heating Systems: a Guide for Institutional and Commercial Biomass Installations" is a good read.

Some general comments about wood chip applications is they do not scale down well. There are a lot of moving parts in the wood feeding system no matter what the size. The chips are non uniform and but usually in roughly 2" chips. If you are moving tons per hours, the chips flow pretty well but if you are try to move small volumes, the chips clump. Wood chips are generally green and wet when delivered. Let them sit too long and they degrade and sometimes catch fire or mold. If you handle them wet, they tend to be a problem in winter where they are right on edge of freezing, its real easy to get to the point where the chips freeze in clumps if the conditions are right. Many of VT installations very quickly had to switch to "premium" wood chips supplied by one or two suppliers at a premium cost as they couldn't handle the standard grade chips. Chips can be very deceiving, from 20' away they look like uniform chips but get closer and you frequently will find buried under the outer layer sticks and staves which can really foul things up.

Most of the small institutional biomass chip installations were heavily subsidized so they could afford to put the system in. The general preference for small institutional or commercial units are pellet boilers. Pellets may be more expensive but the scale down far better than a biomass plant. I have heard second hand from fairly reliable sources that the amount of day to day attention from the plant staff is a lot higher than they were told when the system was built to the point where the staff has to be increased or diverted to deal with wood handling issues.

Another aspect is depending on the size you could get into the EPA boiler MACT regs which is something you really want to avoid

That would depend on the level of automation and design of the boiler to a large degree. Different moisture levels of the fuel demand a different grate system also. Setting up for one and actually trying to burn another would be disaster.
 
Most of the small institutional biomass chip installations were heavily subsidized so they could afford to put the system in. The general preference for small institutional or commercial units are pellet boilers. Pellets may be more expensive but the scale down far better than a biomass plant. I have heard second hand from fairly reliable sources that the amount of day to day attention from the plant staff is a lot higher than they were told when the system was built to the point where the staff has to be increased or diverted to deal with wood handling issues.

I'm sure there are plenty of these systems that do in fact pay their own way, but it's hard to ignore the prevalence of installations that would never would have gotten rolling without plenty of tax dollar lubrication.
 
I have heard second hand from fairly reliable sources that the amount of day to day attention from the plant staff is a lot higher than they were told when the system was built to the point where the staff has to be increased or diverted to deal with wood handling issues.

I was promised all I had to do was press the green button and remove a wheelbarrow of ash per year. Our daily duties would not be effected anymore than any other boiler!

We've hired an extra guy, and a 10 yrd container of ash goes out once a week in the winter. However, the plant did pay for itself in fuel savings in 3 years.
 
I looked into this some years back.

The local High School went Biomass with Gas back up. I forget the name, Swedish design US manufactured.

In Germany, UK etc you can chip for the year, where I am you would end up with a solid lump. The school chips every 2 weeks or so and use containers that look like roll on roll off, essentially they do not chip more than they can store inside.

From a cost perspective the material handling costs make it not costs effective for household use for most.

Wood here dries pretty quick and I doubt moisture levels would eve be near 35%.

Logically you would have a central chipping operation for multiple customers, I think I saw a co op operation like this in Ireland. Outsource the collection, chipping and supply of the product. I think some of the Irish cases I saw they just charged you by the energy consumed, they supplied everything.
 
Wood here dries pretty quick and I doubt moisture levels would eve be near 35%.

My only simple thought, when chips or biomass are in a pile, they don't necessarily dry. I've seen a few mega plies catch fire on their own.
 
I will have to find my moisture meter, where I am now is the opposite extreme to where I have lived most my life. High altitude arid plenty of sun, after a couple of years wood is down to single digits, too dry? nobody bothers storing under cover.

The chip systems apart from the local school I have seen have been in very different climates, low altitude, wet occasional rather than constant freeze risks. There the norm seemed to be to chip late summer and store under cover for the winter.
 
The biomass chips available in the northeast that are affordable to burn (see the BERC report I referred to earlier) are in the 40 to 50% range. The chips are quire green, some of them are chipped directly as they are cut and may end up on the pad in less than 24 hours.

Everyone dreams of sawmill residuals but the pellet plants snap them up as they tend to be drier. The pulp mills tends to grab the good chips, so what get sold for biomass fuel are the dregs no one else wants.
 
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Good post peakbagger. I've hauled hundreds of loads(35 ton per trip) out of various chip mills, stud wood mills, hog fuel loads, etc. Nothing sits on the ground for long. Maybe a day or two. Only time it sits is if the mill wants it to ferment for a reason. Sawdust/shavings can't sit for long, turns bad quickly.

The only thing left is bark and low quality crap. Which will be bought quickly if you've got a cogeneration plant or plants within 200 miles or less.
 
Does anyone use a wood chip boiler, either dry chip or green chip, in a large residential to small/medium commercial application? If so, how has it worked? What's really good? What's not what was expected? etc.? A local school has an interest in taking a look at this because it has a local source of chips, both dry and green. Thanks.
Hello jebatty. We make an Austrian designed two stage chip boiler in Troy,NY. Company name is Evoworld. The boilers are being built at Troy Boiler Works. They are ASME code and getting labled this Spring. They burn 30% and under chip 2 1/2" and down. I have plenty of information on the system. Product range is from 80MBTU to 1.7MMBTU. How do I get information to you to you?
 
Thanks for the info. I am waiting for more preliminary info before proceeding further.
 
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