[Stoves] Testing to determine source of CO

[Frank Shields]

Dear Crispin,

Thanks - very interesting and I also like the term sneagage. 

If CO can sneak past the secondary then along with CO can be a lot of pyrolysis gases. It being easy to measure CO and solving that problem will solve others and, it seems, that has been your goal for many years. Now I understand your reason being so focused on measuring CO much better. 

I do think a compressed tank of CO would help in that research to find the best configuration for the physical design of the combustion chamber to reduce the amount of CO sneaking around the secondary. Knowing the exact source of the CO (from the tank) will eliminate a lot of variables as we make measurement while adjusting the flow. 

A very productive Post (for me) - thanks

Regards

Frank



Frank Shields
franke at cruzio.com




> On Sep 20, 2015, at 11:06 AM, Crispin Pemberton-Pigott <crispinpigott at outlook.com> wrote:
> 
> Dear Frank
>  
> There is a crack at the first part of your letter:
>  
> The CO can arise from primary combustion and escape all the secondary stage by ‘running around the edges’, something Tom Miles said is called ‘sneakage’. Love the term!
>  
> So having observed this to a major cause of CO in the Moingolian traditional stove, I tried installing a flame tube to have the existing flames continue their burn inside the pipe with the CO and other gases drawn in – it is the only way out of the chamber.
>  
> The result was that a significant portion of the CO was burned in the ‘secondary combustion’ if you can call it that.
>  
> I will not repeat the photo. The chamber was ripe for sneakage because the grates are far too large, the combustion chambers cold in the corners and the excess air level far too high to burn properly.
>  
> I think the correct answer to your questions is that everything comes from a different place in different stoves. CO can arise any time. How much O2 is available between two glowing particles of fuel? Any? Probably not. CO arises easily in that micro-environment and the blue flame nearby is the burning of it. 
>  
> Regards
> Crispin
>  
>  
>  
> Greetings Stovers,
>  
> The question I have is does the CO measured in the stack after the secondary combustion come from Primary Combustion (PC) or Secondary Combustion (SC)? 
>  
> As I understand how it works{
>  
> We know the primary combustion will produce large organic pyrolysis gases until the internal oxygen and hydrogen is consumed then will switch to releasing heat with added outside oxygen as the solid goes to CO and CO to CO2.
>  
> So is the CO found in the stack from CO produced in the PC making its way through the SC or from incomplete combustion of large organic structures not properly prepared for the SC? 
>  
> If we were to set up a stove operating and measure the CO in the stack, then introduce CO along with the primary air from a compressed CO tank - would we see an increase in CO in the stack? or is it easily and completely combusted in the secondary? If not seeing any and we kept increasing the CO being delivered how high can we go before seeing ‘break through’? And then if we increased primary air will the CO delivered combust in the combustion chamber increase CO2 in the stack and increase combustion chamber temperature?
>  
> Im thinking the CO produced in the PC is very important in controlling combustion chamber temperatures that prepare the complex pyrolysis gases for the SC. 
>  
>  
> Im sure this simple experiment must have been done somewhere and wondering what the results are. 
>  
> Regards
>  
> Frank
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