Could someone answer this pellet question.

[Havlat24]

Greetings,
I had a bunch of limbs from the trees cut of of our property and broke down and rented a chipper to rid my life of the mess. Some of the limbs were 4" dia. after chipping all day I had quite a large pile.These limbs were laying downed for 8months and when shoveled into our basement stove burned quite well.
Mike

If you would have chipped the limbs when they were freshly cut, and then tried to burn them, they probably would not have burned all that well. The amount of time requried to dry a 4" diameter piece of wood would be minimal. As opposed to a 30" diameter tree. We harvest all of our mill's timber in the winter due to the muskeg soft ground here, by early the following year December, were running some pretty dry stock. Some moisture has escaped, but the sapwood still holds alot of moisture. I dont know if you guys know Veneer but the first 5-10 inches of the oustide of the log is still 50-60% moisture content in a 20-30" block..spruce or pine, even the heart wood needs to be dried as its still over 30% moisture content. Balsam would be from 70-150% moisture.

I dont disagree that a dry chip would burn just as good a dried piece of wood. A green chip however...doubtful

 

[restorer]

Havlat,
Is your mill rotary cutting veneers for sheet stock? Is your slash mostly bark and odd outer edges? Veneers dry very quickly because of the thinness and expose to air. Do you ship long distance or is there a finish product plant close by?

 

[Havlat24]

Havlat,
Is your mill rotary cutting veneers for sheet stock? Is your slash mostly bark and odd outer edges? Veneers dry very quickly because of the thinness and expose to air. Do you ship long distance or is there a finish product plant close by?

Yes, and yes. We're a 2 line spindle lathe operation. Both lathe's run at about a 1000 fpm. Our target daily production (2x8 hour shifts) is about 1.2 million sq feet 3/8's volume or about 110,000 4'x8' sheets of veneer. Our operation is divided into 2 divisions. One operation is the "green end" and the other is the "finishing end". Were operated by West Fraser. Our veneer is shipped 2 hours south where it is dryed and processed into plywood at our sister plant.

In response to your question, yes we "round-up" every block before we peel veneer However, the blocks are debarked prior to conditioning, but all the material involved with the round up process is chipped in our veneer chipper. (Sometimes bark and all...thats a whole other issue..)

Veneer does dry significantly faster then say solid wood lumber. I would say depending on the moisture sort, I'm told anywhere from 4-8 minutes is required to dry a sheet of veneer. I would be what you would call the green side QC. I work with another Quality Manager who supervises the finishing end. The veneer dryers are not located on our site, so my involvement with that process is limited to ensuring our moisture sorts are accurate, in this we try to limit the amount of redry, or over-dried veneer sheets.

If anybody has any other question about veneer or lumber manufacturing I am sure I can add some insight.. =)

 

[restorer]

Havlat,
I appreciate all you have said. I assume the green side is core wood and the dry side is face wood. I don't think many of the burners understand the scope of forest products, not that I do, but you have given me a great nut shell of insight. If you have the time would you consider a series of posts on the products you make and all the side industry, including pellet processing, waste fluids, even how you power your plant. I am familiar with mills that use their waste to provide 130% of power and put lots back on the grid. I think we all should understand our part in the forest products industry.

 

[smirnov3]

The VTHR guy claims that he can get 50% wet wod chips to burn in a custom made furnace. Most of what his web page says make sense, but he doesn't specify how he starts the fire - That, to mee seems like it would be the tricky part:

His fuel is combustion gasses created by super-heating wet wood
But where do you get the initial heat from?

 

[Havlat24]

Havlat,
I appreciate all you have said. I assume the green side is core wood and the dry side is face wood. I don't think many of the burners understand the scope of forest products, not that I do, but you have given me a great nut shell of insight. If you have the time would you consider a series of posts on the products you make and all the side industry, including pellet processing, waste fluids, even how you power your plant. I am familiar with mills that use their waste to provide 130% of power and put lots back on the grid. I think we all should understand our part in the forest products industry.

Actually we produce all plies of the plywood. Full sheet stock is produced, and sorted into 3 moisture sort categories. Heavy Sap, Light Sap, and Heart. Obviously the 3 have different drying times. The sheets are clipped with a rotary clipper into sheets. We use a ultra sensitive light system that shines a beam of light through the veneer, and this is used to clip out defects such as holes, bark, and to some extent rot and decay. About 2 feet before the light scanner, are 13 moisture heads. So we scan the veneer for moisture, and defects. Of course some defects are allowed in the core stock, holes 8" by 3" can be patched on the layup line, as well a considerable amount of "whitespeck" sap stains, cracks, splits, knot holes are permitted.

If there is defect, the clipper will clip the defect out, at the beginning of most ribbons of veneer it takes a good 20 - 100" of clipped narrower panels, which are recovered and piled by hand, these are dried, and cut in half and used for corestock.. As well, we can recover "fish or core" also called half length panels (51") and these are automatic corestock. The plywood finishing plant can also take the narrower half panel sheets, and glue them together to make full sheets. Thicker Plywood, usually uses 2 outside plies, 2 inside half lenght panel plies, and 1-2 full length core plies.

When the sheets are dried, they are scanned and graded again at the other division. They have totally computerized automatic grading systems, sheets with alot of cracks, splits, holes, bigger knots, are inner ply corestock. As you guessed, the nicer sheets are outer ply sheets. Also 20% of our production, is used in a high value product. Pretty much perfect veneer sheets on the outerplies. We also produce a Tongue and Groove product for flooring. All at the finishing mill.

I can surely post some informative posts on all the things requested. I'll do it tomorrow. I have been involved with the forest products industry and several mill sites, and can answer most process questions involving sawmills planers, and veneer mills.

For most people, if you can ever get the chance to see a veneer lathe run, its one of those shock and awe things. 30" block goes into the lathe, 10 seconds later, its a 200 foot sheet of 1/8 of an inch veneer. Whats amazing is we can run at this speed, and keep our size control within a few thousands of an inch...

Take it easy guys.


Talk to you guys later.

 

[Havlat24]

The VTHR guy claims that he can get 50% wet wod chips to burn in a custom made furnace. Most of what his web page says make sense, but he doesn't specify how he starts the fire - That, to mee seems like it would be the tricky part:

His fuel is combustion gasses created by super-heating wet wood
But where do you get the initial heat from?

Im not an expert on burning wood. I do however understand the basic principles of wood fibre moisture content. And I can assure you, throw a bucket of green chips into your woodstove, and your fire is going to go out. If you can dry those chips out, then you'd be in business.

I do know that green spruce and pine take anywhere from 17-24 hours drying time in a kiln (200+ degree Celcius) to reduce the moisture content to below 19%.

 

[slowzuki]

The trick with burning green wood is getting it started first. The heat from the first burning chips dries the following ones. This is important because if you burn dry chips they burn too fast and smoke and not enough air can get in to burn right.

Toss a pile of planer shaving on the fire, it skips across the surface but takes a while to burn down into the middle.

My experience with veneer mills was investigating a fire at one. Boy do they ever burn fast. The dryers frequently had fires in the past, the staff were pretty accustomed to putting them out.

 

[Havlat24]

The trick with burning green wood is getting it started first. The heat from the first burning chips dries the following ones. This is important because if you burn dry chips they burn too fast and smoke and not enough air can get in to burn right.

Toss a pile of planer shaving on the fire, it skips across the surface but takes a while to burn down into the middle.

My experience with veneer mills was investigating a fire at one. Boy do they ever burn fast. The dryers frequently had fires in the past, the staff were pretty accustomed to putting them out.

I would imagine they would burn fast.....as I said we dont dry veneer onsite, all the fibre is green. We do have a planer thou and dry kiln.....potential for fire is there..