Random Lengths, episode 2, why do the woodchips "smoke"?
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- เผยแพร่เมื่อ 1 ม.ค. 2017
- Howdy TH-camrs!
welcome to this second episode of random lengths. today we're taking a peek at a steaming pile of woodchips.
most of us have seen huge piles of woodchips that emit wisps of steam on cool days. so here i'm putting the science of what is going on biochemically into laymans terms. this particular form of chips is referred to as "hog fuel" and is more prone to fermentation than woodchips destined for paper production due to a higher concentration of sapwood material and also the chip size. normally a different type of fungus attacks dead wood and begins the process of decomposition, but yeasts quickly find their way onto the chips and a readily available food source and immediately go to work in breaking down the sugars present in the fluids still contained in the chips.
music:
Road to Moscow
by Jinglepunks - แนวปฏิบัติและการใช้ชีวิต
Great video brother!
The coal oxidizes just like any other organic material. This is a serious concern of large coal fired power plants. They try to suppress the oxidation by compaction and some topical applications. I'm not familiar with any of the latter chemicals.
Glad you are over the P-neumonia,
Rollie
I'm an arborist. I have a chipper. I live on a hill. I have a really big chip pile. it's been growing for the last 20 years. It's close to 20 feet deep at the deep end. It's been steaming the whole time. This spontaneous combustion thing baffles me. I understand that biological activity produces heat and that that heat can build up especially in a deep pile. But the heat can't build up more than the source. And that source the bacteria or yeast can only handle so much heat and then it dies off. No more source so no more heat build up. My understanding is that most organisms die off around 130 F. I think the any sort of ignition of the chips would be closer to 500 F. Am I missing something? A chemical reaction or something?
the depth of the pile also plays a major role in the spontaneous combustion as pressure in the material column increases with depth and also creates heat. there's a couple of crazy finns that have a youtube channel called "beyond the press" where they take various materials and put them in a hydraulic press and crush them. wood and paper often explode violently when pressure is applied. it's along those lines of physics that the spontaneous combustion occurs. granted the pressure is no where near as high but if conditions are just right the chip pile will ignite and smolder.
the ignition temperature of wood is around 150 deg fahrenheit and it also begins to char between 120 and 150 deg fahrenheit so the fermentation temperature alone is almost enough to get it going. add the pressure and voila!
I think this channel is interesting and informative
thank you :) i do try to make it that way. i still make mistakes but do try to keep them to a minimum. thanks for watching and commenting!
Coal piles will do the same thing.
interesting, i've never been around big coal piles, so i've never seen them do that. you have any idea what might be going on there?
thanks for watching and commenting!