KD Birch auction

[s.varty]

They could have been as low as 10% when leaving the kiln ..... however wood will only be as dry as its surrounding humidity , so will probably have absorbed water from the atmosphere , even indoors in the UK at this time of year ... so kiln drying was a bit wasted really , but will still be great firewood I would think !

 

Ive always thought this of kiln drying, But it does get the moisture content down quicker than air drying I suppose

[Alycidon]

I understood that a moisture reading needed to be made from a face of a freshly split log. Average of three readings taken from the face (then repeated several times from random pieces) - that I believe is the Woodsure (HETAS) standard.

 

It is.

 

I have seen several comments from potential customers of stove/fire ready kiln dried this winter that customers report poor burning. I have found MCs of just over 30% in one lot.

 

No doubt it had be kilned, just not for long enough.

 

A

[PremiumWood]

oh yeah ash firewood good to go at 27%. i was just trying to get my head round kilning as i still dont think its the way forward

 

Sent from my GT-I8160 using Tapatalk 2

 

I don't see anything wrong with kilning, as long as the kiln is fired up by wood waste or straw or anyth similar. Once you have a kiln set up, you can sell much more dry logs with less investment. Basically you don't need to prepare 2 years in advance, you buy round wood as you go .

[Alycidon]

To my knowledge, maximum heat output is reached when hardwood logs are down to around 22%, this is what we usually aim for. No point drying to 16 or lower as logs will burn too quickly.

 

The reason why logs went on auction is mould

 

 

wrong, look at the FC info. page 2 here.

 

http://www.forestry.gov.uk/pdf/eng-woodfuel-woodasfuelguide.pdf/$FILE/eng-woodfuel-woodasfuelguide.pdf

 

The drier it is the less energy is wasted drying moisture out so the higher the heat output.

 

A

Edited February 25, 2014 by Alycidon

[Alycidon]

They could have been as low as 10% when leaving the kiln ..... however wood will only be as dry as its surrounding humidity , so will probably have absorbed water from the atmosphere , even indoors in the UK at this time of year ... so kiln drying was a bit wasted really , but will still be great firewood I would think !

 

 

Undoubtedly right, my own air dried was about 7% in Sept, last bags of it went out about 2 weeks ago at around 14%. Kept in an open barn, roof and partly closed on one side only.

 

If the wood in question was 10% in Dec when the guy said it was kilned no way will it now be as wet as it is unless it floated over the North Sea.

 

A

[Woodworks]

Undoubtedly right, my own air dried was about 7% in Sept, last bags of it went out about 2 weeks ago at around 14%. Kept in an open barn, roof and partly closed on one side only.

 

If the wood in question was 10% in Dec when the guy said it was kilned no way will it now be as wet as it is unless it floated over the North Sea.

 

A

 

Ha ha

 

Harsh but true

 

Even down here on soggy Dartmoor I wont sell logs until down to 25% or less. Most at 20%

 

Sorry Premiumwood you have been totally up front about what you have for auction and it will probably make perfectly good firewood but us air dryers are a bit taken-a-back about how wet kiln dried wood can be.

[Bluecoat]

They could have been as low as 10% when leaving the kiln ..... however wood will only be as dry as its surrounding humidity , so will probably have absorbed water from the atmosphere , even indoors in the UK at this time of year ... so kiln drying was a bit wasted really , but will still be great firewood I would think !

 

So wrong

 

Humidity is measured by calculating how much moisture the surrounding atmosphere is able to hold at its current temerature and is shown as a percentage of this measurement. Florida is famously humid, 100% humidity is not uncommon, so you saying you cant store seasoned firewood there as it will keep absorbing moisture? Moisture content of firewood and humidity of the atmosphere are different things. High humidity will slow the seasoning process but is unlikely to alter moisture content of seasoned firewood by more than a couple of percent.

[eggsarascal]

You're right, high Humidity will slow a natural seasoning process, however, a kiln dry process will chase it and improve the dry weight, ie make the kilo joule (dw) value better quicker but by the cost of kiln drying, nothing comes for nothing eh?

 

Any way dried wood will not grab water by the rate a bag of dried salt would if sat in a humid atmosphere as it's not a naturally hydrophilic matter. It may drench in rain if not protected and grow bacterial/fungal growth and thus ingress it's water mass but if kept under a tarp, jobs a flipping good'un,

 

 

Mrs egg, physicist and full of her opinion.

[PremiumWood]

Rollocks, look at the FC info. page 2 here.

 

http://www.forestry.gov.uk/pdf/eng-woodfuel-woodasfuelguide.pdf//eng-woodfuel-woodasfuelguide.pdf

 

The drier it is the less energy is wasted drying moisture out so the higher the heat output.

 

A

heh nice try, but I'm afraid you are wrong here sir.

Your statement that "The drier it is the less energy is wasted drying moisture out so the higher the heat output." is correct, BUT you forget one important factor. Wood becomes lighter when it gets drier. And heat output is calculated by weight.

1tonne of wood at 30% would lose 20% of its mass if you decide to dry it down to 10%. Yes, calorific value per tonne increases, but it looses 20% of its mass. I've done a simple study on optimum m/c on hardwood logs in the past and came to conclusion that ~22% m/c is what we need to aim for.

[Woodworks]

heh nice try, but I'm afraid you are wrong here sir.

Your statement that "The drier it is the less energy is wasted drying moisture out so the higher the heat output." is correct, BUT you forget one important factor. Wood becomes lighter when it gets drier. And heat output is calculated by weight.

1tonne of wood at 30% would lose 20% of its mass if you decide to dry it down to 10%. Yes, calorific value per tonne increases, but it looses 20% of its mass. I've done a simple study on optimum m/c on hardwood logs in the past and came to conclusion that ~22% m/c is what we need to aim for.

 

Are you suggesting that the water present in the wood has no detrimental effect to it's calorific output?