Are there advantages to wood pellets over wood chips?

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In summary, wood chips and wood pellets can both be automatically fed into the burn chamber and make char that is small enough to be automatically removed. However, pellets require two extra steps and more energy and machinery to produce from whole wood compared to chips. The advantage of pellets is that they are dried to a low moisture content, which increases combustion efficiency and prevents rot. It is more efficient to dry pellets en-masse rather than letting wood self-dry as it burns.
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Stormer
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Both wood chips and wood pellets can be automatically feed into the burn chamber by Screw Conveyors, transport belts, and vibratory feeders. And both make char that is small enough to be automatically removed from the burn chamber. And both also has a shape and size that allows enough air to move trug the burn pile to feed the fire (unlike sawdust that will compact and stop to much air for it to burn).

But to make pellets you have to go trough two more steps (making chips into sawdust, and then pelletize it) to make them from whole wood compared to wood chips. And it takes more energy, and more machinery and time. So why are pellets used and not just wood chips? Is there any advantage i have missed? Or is it just to have a way to use sawdust waste from production of wood products for something useful? And in that case wasteful if whole wood pieces is used to make it?
 
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Wood pellets are also dried to a specified, low, moisture content. Green wood can be as much as 50% water by weight. Much of the energy from burning green wood goes to evaporating that water. It also reduces the boiler efficiency.

I saw one estimate that about 20% of the wood needs to be burned to dry the remaining wood. I saw another plot of boiler efficiency vs wood moisture. The increase in combustion efficiency was much more than the loss of wood burned to dry the wood.

Dry pellets do not rot. I don't know how fast green wood chips rot, but I remember sticking my hand into a sawmill sawdust pile. It was hot only a few inches in. Rotten wood gives off less energy when burned.
 
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  • #3
jrmichler said:
Wood pellets are also dried to a specified, low, moisture content.

I guess its more efficient to dry the pellets en-masse than to let the wood self-dry as it burns, or to dry wood chips en-masse?
 
  • #4
Grinkle said:
I guess its more efficient to dry the pellets en-masse than to let the wood self-dry as it burns, or to dry wood chips en-masse?
If you dry it in the fire, the energy needed to convert water to steam and to send the steam up the chimney is subtracted from the heat you put into your room. So yes, it is better to get dried wood from your supplier.
 

1. What is the difference between wood pellets and wood chips?

Wood pellets are small, cylindrical pieces of compressed wood made from sawdust or other wood waste. Wood chips, on the other hand, are larger pieces of wood that have been chipped or shredded.

2. Are there any advantages to using wood pellets instead of wood chips?

Yes, there are several advantages to using wood pellets over wood chips. Wood pellets have a higher energy density, meaning they produce more heat per unit of weight. They also have a lower moisture content, which makes them burn more efficiently and produce less smoke. Additionally, wood pellets are easier to handle and store due to their uniform size and shape.

3. Do wood pellets cost more than wood chips?

In general, wood pellets do cost more than wood chips. However, this cost difference can vary depending on the region and availability of both products. It's important to consider the overall efficiency and heat output when comparing the cost of wood pellets and wood chips.

4. Can wood pellets be used in the same way as wood chips?

Yes, wood pellets can be used in the same way as wood chips. They can be used in residential or commercial heating systems, as well as for cooking and grilling. However, it's important to note that wood pellets may require a different type of equipment or burner than wood chips.

5. Are there any environmental benefits to using wood pellets over wood chips?

Yes, there are several environmental benefits to using wood pellets over wood chips. Wood pellets are made from waste wood materials, which helps to reduce the amount of wood waste in landfills. They also produce fewer emissions and have a lower carbon footprint compared to fossil fuels. Additionally, using wood pellets helps to support sustainable forestry practices.

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