Subject: Re: Can compost get too hot?

From: [email-masked] (Jim Carr)
Date: 28 Apr 93 19:43:07 GMT

In article <[email-masked]> [email-masked] (Paul Harvey) writes:
>
>   ...         "Spontaneous Combustion," something once blamed on witches 
>is also possible.

In article <[email-masked]> [email-masked] (Peter Nelson) writes:
>
>  I'm skeptical about this.  Wood and other cellulose-based 
>  materials require a temperature of about 420 degrees (F) to
>  ignite, but what biological process will continue to occur
>  above approx. 200 degrees?     

Try explaining your skepticism to the farmer whose barn burned down 
because it contained hay that was cut and baled while wet.  What 
happens is that the heat from the biological process will initiate 
an oxidation reaction that leads to a fire.   

--
J. A. Carr       <[email-masked]>           |  "The New Frontier of which I  
Florida State University  B-186               |  speak is not a set of promises
Supercomputer Computations Research Institute |  -- it is a set of challenges."
Tallahassee, FL  32306-4052                   |   John F. Kennedy (15 July 60)

---

From: [email-masked] (Bob McKay)
Date: Mon, 17 May 1993 03:20:37 GMT

[email-masked] (John Snyder) writes:

>>>In article <[email-masked]>, [email-masked] (Peter Nelson) writes:
>>>|> 
>>>|>   I'm skeptical about this.  Wood and other cellulose-based 
>>>|>   materials require a temperature of about 420 degrees (F) to
>>>|>   ignite, but what biological process will continue to occur
>>>|>   above approx. 200 degrees?     
>>>|> 
>>>|> ---peter

(Hope I sorted out the nested attributions right - apologies if not). Peter's
raised a fascinating point, and got me really thinking about this, as I've
grown up on stories of spontaneous combustion. Pretty commonsense folk, who
invested an awful lot of effort in checking the temperatures of their stacks,
and tried hard to make sure they weren't stacked too green. So I'm certainly
disinclined to discount their belief. My best bet? Well, a green stack is 
going to contain lots of stuff other than cellulose; in particular, by the 
time the bugs have been working for awhile, there'll be an awful lot of 
alcohols and esters floating around, some of which will have quite low
ignition temperatures. Also methane and maybe hydrogen. Certainly the temps
won't need to be anything like 420F for ignition (though it's only once the
temp gets up to there that you'll get a runaway fire, of course). I don't
know if any of those would have ignition temps in the biological range, but
even if not, there's also the possibility of catalysis boosting the
temperature above that attained by bio processes

      Cheers
	Bob McKay

-- 
Bob McKay		   	Phone:	+61 6 268 8169	    fax: +61 6 268 8581
Dept. Computer Science,ADFA, Northcott Dve, Campbell ACT 2600 AUSTRALIA