Catalytic stoves v Secondary Air

[Billhook]

Anyone had any experience of either of these?

 

 

[Woodworks]

Interesting video.

 

What he didn't cover is which one would produce the most kWh per kg of wood. On the catalytic stoves when they are running slow and low do the gases get hot enough to burn all the volatiles? 

[neiln]

Yes, once the cat is up to temp.

[neiln]

Blaze king stoves are pretty much the top of the line I believe.  Go on hearth.com and look I'm the long running bk threads.  Bkvp is indeed their VP, posts regularly and sorts out issues when the crop up.  Don't believe they are available this side of the pond. Shame, I like the thought of loading a stove once every 24-36 hours.

[Stere]

Nocticed a few cat stoves are now poppping up this side of the pond, odd they never caught on more yet?

 

 

 

Ashcott Wide Catalyst | Mendip Stoves - Wood Burning Stoves

WWW.MENDIPSTOVES.CO.UK

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Distributor of wood burning, multi fuel, inset and free standing stoves with retailers across the UK. Featuring brands such as...

 

Arada Farringdon Catalyst Eco Design Ready Wood Burning Stove - Stoves Are Us

WWW.STOVESAREUS.CO.UK

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The Arada Farringdon Catalyst wood burner boasts an impressive maximum heat output of 16kW but is ultra...

 

But thet don't make a point of mentioning the nature catalyst part much, in the marketing or infos.....

 

So no idea how much are spares if needed & how long do does the cat stay effective etc.....?

 

Edited March 21, 2021 by Stere

[neiln]

i understand the regs are tighter for cat stoves to allow for some degradation. If the stove is run properly, clean wood, dry wood, and the right temps etc, then i believe the cats do 2, 3, 4 years.  They can be cleaned and given a bit more life..think its boil in vinegar or something like that, but definitely need to factor replacing them every few years and they cost high hundreds of dollars i think.

[neiln]

I think the market for big stoves is not that strong here.  In the US there are a lot of rural homes, big homes with plenty of space and these are often built with wood heat in mind.  Their way has been much more a single, large, centrally located stove, loaded to the gunnels and set to chug along for 8-12-24 hours. 

Iirc the bk Princess is 80-100000 btu/ HR which is 20-25kW.  The bk king is even bigger. The size is probably limiting the take up over here.  I couldn't fit one, but I do like the thought of it!

[Witterings]

I stumbled across the Blaze Kings a while ago and just after we'd had ours installed, I must admit I do like the idea of putting a load on at the start and leaving it for hours as opposed me having to put another log on every 30 / 40 minutes ... even if you only got 4 / 5 hours of burn time instead of the 12+ hours some of the big ones get.

 

I couldn't work out though if they're actually more efficient in other words if there was a smaller one that would last for a few hours would it burn less wood than the amount you'd have to feed a normal stove over an evening or is it just that you'd be putting it all on at once and it just gets through it slowly.

 

If it does burn considerably less, if you're buying in wood at retail prices it wouldn't take long to save the cost of replacing the cat from time to time.

[openspaceman]

11 hours ago, neiln said:

i understand the regs are tighter for cat stoves to allow for some degradation. If the stove is run properly, clean wood, dry wood, and the right temps etc, then i believe the cats do 2, 3, 4 years.  They can be cleaned and given a bit more life..think its boil in vinegar or something like that, but definitely need to factor replacing them every few years and they cost high hundreds of dollars i think.

I cannot understand the need for a catalytic converter on a stove. I understand it on petrol engines where you only have milliseconds to complete the burn and it has to be near enough stoichiometric but on a stove you have a retention time of seconds and massively increased excess air. Even so a catalyst is unlikely to work on those graphitised bits of soot as they are highly recalcitrant.

 

Think of the requirement for burning  being an energy wall which you have to lift the constituents up to until the can burn and fall off the other side, a catalyst  is just like a  lower section of wall so the constituents don'r have to reach as high before they burn.

 

To my mind an electrostatic precipitator would be more sense but until they are mass produced and come down to less than £100  there'll be little uptake. Where to fit one in my set up is the problem. I can only see the chimney top as being viable and that would mean accessing it to service it.

[openspaceman]

On 21/03/2021 at 09:41, Woodworks said:

Interesting video.

His explanations did not make sense to me