Pellet Skid Heights?

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Bkins

Minister of Fire
Hearth Supporter
Mar 16, 2009
623
Jersey Shore
What causes different heights between skids of pellets? The skid the pellets are on are the same? Does it have to do with how much the pellets were compressed, and if so is this bad?

David
 
sometimes the pallets are diff heights, so that could account for some. I have seen some skids that are a few inches taller, and when you open them up, there's really no difference in the pellets themselves. I have to assume that some of it is the pellets "settling" during transport or storage. Robots do the stackign for the most part in these factories, I'm not sure if they "look" to see how uniform they do the job. Good question though, and I have wondered the same thing on several occasions.
 
This is the response I just got back from the pellet people. They have their mill onsite where I picked up the pellets.

The different heights on pallet sizes is caused by different densities of the sawdust we receive from the supplier to process. Sometimes we get a very dense dust that came from a sanding or shaping machine and therefore makes a much denser or 'heavier' pellet. As opposed to other dust that might have come off of a planing process that has more shavings and what we call 'fluff' in it. This dust compacts less densely resulting in a lighter pellet and will obviously take up more space. The BTU output of the pellet is determined by the weight of product you burn and not by the density. I hope all that makes sense....if not let me know and I'll try to explain it a little better.

I got a quick response from them.

I guess it comes down to any number of reasons for the different heights.

David
 
a hardwood pellet will make a shorter stack than a softwood pellet, both are 40# bag but hardwood is denser. Found this on a site about pellets last fall, even had a picture of a ton of hardwood and a ton of softwood showing almost 8" difference in height.
The 1.5 ton or other over 1 ton pallets is caused by the cost of shipping, one ton for each 4'X4' space in a truck or rail car doesn't get close to the usefull load of the transportation. 1.5 ton is the highest I have heard of and it does make for a tall pallet, then you have to worry about the load shifting or falling in transit, and what a forklift can take on angles and ramps.
 
Lots to learn.

BTU,

So back to my basic question. What causes the different pallet heights. I had a difference of 8" between 2 pallets. Is this from something gone wrong in the pelletizing process or do some other factors come into play, such as the variation put into bags. Should "US" pellet users be weighing bags of pellets every so often to see what the counts are? If the bags don't add up to 40 lbs. then the mills would be way ahead by the end of the day. I guess the same would be true if the bag weights are just a average and some bags would be over then for the most count you would get what you paid for. This would be a very bad way to run a production line in my eyes. How do the mills fill/weigh the bags of pellets?

Just from my short time using pellets it seems like some bags are lighter then others. This has been noted from 3 different suppliers. I'm sure most of us have picked up a bag and thought "this is lighter then the other one" Any thoughts are appreciated.

David
 
come on I read it on the net, it has to be true!
 
FYI

(broken link removed)


Wood Pellet Density
Pellet manufacturers compress the wood fiber to a consistent density of at least 40lbs per cubic foot. That means that if you fill a cubic foot container with the pellets (just pour them in), it should weigh at least 40lbs. But it's difficult to compress to that exact density consistently, so most pellet mills compress to 41lbs or 42lbs. It's not uncommon that the pellet could be as dense as 44lbs or more. If one bag of wood pellets is denser than another, it will deliver more fuel to the firepot with each rotation of the augur than the less dense pellet. If you have two brands of pellets, you can stack eight bags of one brand on top of each other next two eight bags of the other brand. The taller stack is the less dense pellet. Being less-dense or more-dense isn't bad, but it does change the fuel-to-air ration in the appliance. If you switch from a less-dense pellet to a more-dense pellet, you will need to reduce your feed rate or increase airflow through the firepot to maintain the correct fuel to air ratio.

-G
 
Bkins said:
What causes different heights between skids of pellets? The skid the pellets are on are the same? Does it have to do with how much the pellets were compressed, and if so is this bad?

David
David,
Another reason for the difference in height is that many manufacturers and retailers double and sometimes triple stack the pallets to increase storage space. This causes the pellets on the lower skids to settle into the void spaces that would otherwise exist between the pellets in the bags due to the extra weight on top. The lowest bags will also often stretch and flatten out slightly. This is especially true if the pellets were shipped by rail box car where the pallets are double stacked and then usually travel a considerable distance all the while being subjected to the shifting and shakeing and motion of the car, even with the dunnage pillows, not to mention the cars being coupled and uncoupled at the interchanges! Hope this helps answer your question.
Greg
 
Thanks for all the replys. It seems there are multiple possible reasons to answer my question. None of it seems to be devious so that is a good thing.

David
 
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