Wayne Seidl on fri 10 nov 06
For some time, I've been planning the construction of an MFT wood-fired
kiln, with auxiliary gas burners. It's still in the planning stages, but
thanks to many, many people, both on this list and others, I believe it to
be a distinct possibility. I expect it to operate both as bisque and cone
10 kiln, and so am trying to incorporate as many "bells and whistles" as
possible. No computer controller planned at this time, since we all know
that computers are notoriously lazy about getting up to stoke. Too darn
busy with math problems, I guess . I'm still researching solar powered
variable closure actuator-controlled gas butterfly valves tied to oxy-probe
and pyrometer signals (yes, really, no more pulse on/off firing)and methane
generators for the gas supply. However, the recent thread(s) on smokeless
firing led me down (yet) another path.
Four years ago, we installed in our VT house a Woodstock Soapstone Co.
woodstove, with a catalytic after-burner. Where before it was not unusual
for us to go through 5-6 cord of wood per winter (it's a very small house on
the north side of a mountain...bad microclimate), with this new stove we're
down to less than three cord per year, a significant savings both in time
and money. In addition, the after-burner on this stove (located out of the
flame path, but in the flue path) has resulted in NO smoke being emitted as
it leaves the chimney. Where before we would choke going outside and
couldn't see across the garden; now nothing (unless we're first starting it
up and have the catalytic burner bypassed.) That was the most startling
change. We're very happy with the stove and it's efficiency, and it is
holding up well. I think the neighbors also appreciate the fact that there's
no more "old smokey" going on.
That led me to think that it might also be possible to adapt a catalytic
after-burner to a kiln.
I'm thinking perhaps a small "collection chamber" at the rear of the ware
chamber, including a "kiln shelf" damper in the stack, and a "bypass" to
allow the catalytic honeycomb to slide left-to-right across the entrance to
the flue when in use, forcing the gases to pass through it to re-burn, then
into the stack for exit to the great outdoors. Obviously, issues such as
reduction/back pressure are going to arise and will need to be finessed as
the firing continues, but this seems to be the easiest way to do it. Easier
than a scrubber, anyway.
The catalytic honeycombs I have seen sold as replacements for those
currently in use by major stove manufacturers are surprisingly affordable.
Two of them, (enough to easily cover a 12X12 flue exit) would come to a
little less than $500, and would insure EPA compliance in residential areas,
since there is no visible smoke. I haven't checked into particulate
emissions yet, but I'm sure standards and regulations exist (sigh).
If anyone has any comments regarding the idea, why it will or won't work, I
would appreciate hearing from you.
Best,
Wayne Seidl
Taylor Hendrix on fri 10 nov 06
And I would love any list member's explaination on what these
catalytic after-burners are and how they work.
The session "Wood Firing in an Institutional Setting" at NAU touched
on the smoke concerns. I was very interested in what some of the
presenters had to say. BJ, David, Tony, Paul, anyone remember who it
was that put a blower at his mixing? chamber to remove smoke from the
anagama firings? He had the pics of the stack with and without smoke.
Here is a list of the participants from the website.
Jack Troy (USA, moderator)
Bede Clark (USA)
Doug Jeppeson (USA)
Stephen Mickey (USA)
Priscilla Mouritzen (Denmark)
Taylor, in Rockport TX
Wayne Seidl on fri 10 nov 06
Taylor:
Go here:
http://www.condar.com/
and here:
http://www.stovecombustors.com/index.html
These products will give you a good idea of what the afterburner is/does.
Same basic thing as what is in your car catalytic converter.
The ceramic/platinum compound heats up and burns the leftover particulates
and "soot" (hydrocarbons) which means less get emitted into the air.
Best,
Wayne Seidl
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Taylor Hendrix
Sent: Friday, November 10, 2006 4:16 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: LONGISH: Some thoughtsand questions on "smokeless" wood kilns
And I would love any list member's explaination on what these
catalytic after-burners are and how they work.
The session "Wood Firing in an Institutional Setting" at NAU touched
on the smoke concerns. I was very interested in what some of the
presenters had to say. BJ, David, Tony, Paul, anyone remember who it
was that put a blower at his mixing? chamber to remove smoke from the
anagama firings? He had the pics of the stack with and without smoke.
Here is a list of the participants from the website.
Jack Troy (USA, moderator)
Bede Clark (USA)
Doug Jeppeson (USA)
Stephen Mickey (USA)
Priscilla Mouritzen (Denmark)
Taylor, in Rockport TX
____________________________________________________________________________
__
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Russell Sheptak on fri 10 nov 06
=46rom =20
http://www.hpba.org/fileadmin/factsheets/product/EPACertWoodburning.pdf
Catalytic stoves employ a catalytic converter which works
as an afterburner to reduce wood smoke. The converter is a cast
ceramic honeycomb coated with either platinum or palladium.
Once the converter is pre-heated to light-off temperature
(500=96600 degrees Fahrenheit), the
smoke is routed through the catalyst
which burns the tars, vapors and other
organic compounds that make up
wood smoke.
----------------------
Rus Sheptak rus@sonic.net
On Nov 10, 2006, at 1:15 PM, Taylor Hendrix wrote:
> And I would love any list member's explaination on what these
> catalytic after-burners are and how they work.
>
> The session "Wood Firing in an Institutional Setting" at NAU touched
> on the smoke concerns. I was very interested in what some of the
> presenters had to say. BJ, David, Tony, Paul, anyone remember who it
> was that put a blower at his mixing? chamber to remove smoke from the
> anagama firings? He had the pics of the stack with and without smoke.
>
> Here is a list of the participants from the website.
> Jack Troy (USA, moderator)
> Bede Clark (USA)
> Doug Jeppeson (USA)
> Stephen Mickey (USA)
> Priscilla Mouritzen (Denmark)
>
> Taylor, in Rockport TX
>
> =
_______________________________________________________________________=20=
> _______
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at =20
> melpots@pclink.com.
>
>
Paul Herman on fri 10 nov 06
Hi Wayne,
The thing that comes to mind is, all the after burners need to be up
to high temperature before they start to work.
On kilns, the sutema, or collection box has to be up to orange heat
or above before it will burn up the smoke. This led to the insane
tactic of burning lots of propane to heat the exit flues enough to
make it work. Kind of destroys any attempt at reducing greenhouse
gasses. I heard tell of the Tozan kiln in Victoria, BC burning 1500
gallons of propane to heat the after burner for one firing. That's nuts.
By the time the base of the chimney is red in our kiln, we've already
made a lot of smoke.
As far as a catalytic converter on a wood kiln, I've never heard of
such a beast. Perhaps you could be the one to break ground on this. I
suspect a kiln would need one much larger than wood stove size, and
able to stand the higher temperatures involved.
The last issue of "The Logbook" has a good article by Bede Clark on
their successful experiments with blowing air into the sutema. It
sounds like it worked well for them (after the temp was high enough).
He also gave a talk in AZ at the woodfire conference. At lower temps,
I imagine it would dilute the smoke, from black to grey. If you don't
subscribe to The Logbook, I highly recommend it.
I guess I like Owen Rye's take on it, you don't have a problem with
smoke, but there's a big problem with overbreeding....
Good firings,
Paul Herman
Great Basin Pottery
Doyle, California US
http://greatbasinpottery.com
On Nov 10, 2006, at 11:00 AM, Wayne Seidl wrote:
> For some time, I've been planning the construction of an MFT wood-
> fired
> kiln, with auxiliary gas burners. It's still in the planning
> stages, but
> thanks to many, many people, both on this list and others, I
> believe it to
> be a distinct possibility. I expect it to operate both as bisque
> and cone
> 10 kiln, and so am trying to incorporate as many "bells and
> whistles" as
> possible. No computer controller planned at this time, since we
> all know
> that computers are notoriously lazy about getting up to stoke. Too
> darn
> busy with math problems, I guess . I'm still researching solar
> powered
> variable closure actuator-controlled gas butterfly valves tied to
> oxy-probe
> and pyrometer signals (yes, really, no more pulse on/off firing)and
> methane
> generators for the gas supply. However, the recent thread(s) on
> smokeless
> firing led me down (yet) another path.
>
> Four years ago, we installed in our VT house a Woodstock Soapstone Co.
> woodstove, with a catalytic after-burner. Where before it was not
> unusual
> for us to go through 5-6 cord of wood per winter (it's a very small
> house on
> the north side of a mountain...bad microclimate), with this new
> stove we're
> down to less than three cord per year, a significant savings both
> in time
> and money. In addition, the after-burner on this stove (located
> out of the
> flame path, but in the flue path) has resulted in NO smoke being
> emitted as
> it leaves the chimney. Where before we would choke going outside and
> couldn't see across the garden; now nothing (unless we're first
> starting it
> up and have the catalytic burner bypassed.) That was the most
> startling
> change. We're very happy with the stove and it's efficiency, and
> it is
> holding up well. I think the neighbors also appreciate the fact
> that there's
> no more "old smokey" going on.
>
> That led me to think that it might also be possible to adapt a
> catalytic
> after-burner to a kiln.
> I'm thinking perhaps a small "collection chamber" at the rear of
> the ware
> chamber, including a "kiln shelf" damper in the stack, and a
> "bypass" to
> allow the catalytic honeycomb to slide left-to-right across the
> entrance to
> the flue when in use, forcing the gases to pass through it to re-
> burn, then
> into the stack for exit to the great outdoors. Obviously, issues
> such as
> reduction/back pressure are going to arise and will need to be
> finessed as
> the firing continues, but this seems to be the easiest way to do
> it. Easier
> than a scrubber, anyway.
>
> The catalytic honeycombs I have seen sold as replacements for those
> currently in use by major stove manufacturers are surprisingly
> affordable.
> Two of them, (enough to easily cover a 12X12 flue exit) would come
> to a
> little less than $500, and would insure EPA compliance in
> residential areas,
> since there is no visible smoke. I haven't checked into particulate
> emissions yet, but I'm sure standards and regulations exist (sigh).
>
> If anyone has any comments regarding the idea, why it will or won't
> work, I
> would appreciate hearing from you.
>
> Best,
> Wayne Seidl
Ivor and Olive Lewis on sat 11 nov 06
Dear Wayne,
On the face of it this sounds like a good idea.
The only problem I foresee is the effects of impurities from your fuel. =
Catalytic systems are notorious for the ease with which catalytic =
materials can be inactivated. What do the makers say about their units?
But if you can afford it why not try.
Best regards,
Ivor
Ivor and Olive Lewis on sat 11 nov 06
I think there is some confused thinking going on here.
The catalytic pollution control unit of an automobile is designed to =
deal with the effluent created when a volume of petroleum reacts =
chemically with a precise volume of air. At the temperature that this =
happens nitrogen in the air becomes involves and forms one or more of =
the nitrogen oxides. These are responsible for that great phenomenon =
"Smog". I am sure Wikipedia has all the griff on this. Anyway, when the =
oxygen sensor responds and informs the onboard computer, it takes care =
of the nitrogen oxides and the carbon monoxide by bleeding air into the =
system. In a Potter's kiln the problem is different. Control of =
combustion is imprecise. Ideally there should be no smoke because you =
want to get all of the energy out of your fuel.=20
What is needed is a way to bleed air into the Stack without destroying =
draught pull and have a small flame, or an electronic device there, to =
ignite the wasted fuel once the two reagents have thoroughly mixed.
Lee Love on sat 11 nov 06
This has been the current topic at woodkiln list. I put up a
design and sketch of a couple possibilities
I don't the the outboard burner boxes on the MFT is the way to go..
http://groups.google.com/group/WoodKiln
--
Lee in Mashiko, Japan
http://potters.blogspot.com/
"Let the beauty we love be what we do." - Rumi
"When we all do better. We ALL do better." -Paul Wellstone
clennell on sat 11 nov 06
Sour Cherry Pottery
> And I would love any list member's explaination on what these
> catalytic after-burners are and how they work.
>
> The session "Wood Firing in an Institutional Setting" at NAU touched
> on the smoke concerns. I was very interested in what some of the
> presenters had to say. BJ, David, Tony, Paul, anyone remember who it
> was that put a blower at his mixing? chamber to remove smoke from the
> anagama firings? He had the pics of the stack with and without smoke.
>
>
Taylor: It was Bede Clark. A maker of pretty nice pots as well!
Cheers,
Tony
Wayne Seidl on sat 11 nov 06
Dear Ivor:
The manufacturers are operating under the assumption that their (woodstove)
units should be replaced every five years. I do not know under which
conditions they expect the stoves to be fired or how they arrived at that
figure. Our stove, which is being used continually from the end of August to
the beginning of May has shown no such need. We clean the converter twice
yearly, and that may have had some effect in prolonging its life span.
Automotive converters appear to be good "for the life of the vehicle". In
my case, that makes it 13 years of daily use with no problems.
Certainly, kilns are not fired daily for years. If they are, then I need to
go learn from that potter .
Best,
Wayne Seidl
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Ivor and Olive
Lewis
Sent: Saturday, November 11, 2006 12:55 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: LONGISH: Some thoughtsand questions on "smokeless" wood kilns
Dear Wayne,
On the face of it this sounds like a good idea.
The only problem I foresee is the effects of impurities from your fuel.
Catalytic systems are notorious for the ease with which catalytic materials
can be inactivated. What do the makers say about their units?
But if you can afford it why not try.
Best regards,
Ivor
____________________________________________________________________________
__
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Wayne Seidl on sat 11 nov 06
Dear Ivor:
Catalytic converters also serve to burn additional unburned hydrocarbon
emissions.
Introduction of additional air for the flue can be accomplished by the use
of a "collection chamber" or sutema at the back of the ware chamber. It was
demonstrated in the article in "The Log Book" that the addition of air from
a small blower in that chamber eliminated all the smoke from the firing, the
blower being used while the kiln was being stoked. The addition of a
catalytic converter between the ware chamber and the sutema would serve only
to re-burn any particulates still in the flue gases, and might eliminate the
need for the blower once the converter is up to temperature (around 400F).
Keeping the catalytic converter in the ware chamber allows one to take
advantage of the heat generated to add to the heat from the fire. I note
that many people have mentioned that the back of their kiln is cooler than
the front. This might help eliminate that disparity to some degree.
There have also been suggestions that pre-heating the combustion air by
piping it alongside or in the flue might help as well, and sealing the
firebox to accommodate the introduction of heated air would allow for
precise control of combustion, in effect turning the kiln into a giant "wood
stove".
Granted, this is certainly going to take a LOT more research. I see a large
increase in efficiency through less fuel used, as well as a strong reduction
in emissions possible from these modifications. I will continue to work on
it, and keep the list posted with any findings.
Best,
Wayne Seidl
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Ivor and Olive
Lewis
Sent: Saturday, November 11, 2006 1:22 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: LONGISH: Some thoughtsand questions on "smokeless" wood kilns
I think there is some confused thinking going on here.
The catalytic pollution control unit of an automobile is designed to deal
with the effluent created when a volume of petroleum reacts chemically with
a precise volume of air. At the temperature that this happens nitrogen in
the air becomes involves and forms one or more of the nitrogen oxides. These
are responsible for that great phenomenon "Smog". I am sure Wikipedia has
all the griff on this. Anyway, when the oxygen sensor responds and informs
the onboard computer, it takes care of the nitrogen oxides and the carbon
monoxide by bleeding air into the system. In a Potter's kiln the problem is
different. Control of combustion is imprecise. Ideally there should be no
smoke because you want to get all of the energy out of your fuel.
What is needed is a way to bleed air into the Stack without destroying
draught pull and have a small flame, or an electronic device there, to
ignite the wasted fuel once the two reagents have thoroughly mixed.
____________________________________________________________________________
__
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
Sandy Miller on sat 11 nov 06
For a guy who bisque fires his pots in his
self cleaning oven this is very impressive!
so just where is the collection chamber in
that self cleaning oven?
Sandy Miller
Wayne Seidl wrote:
Dear Ivor:
Catalytic converters also serve to burn additional unburned hydrocarbon
emissions.
Introduction of additional air for the flue can be accomplished by the use
of a "collection chamber" or sutema at the back of the ware chamber. It was
demonstrated in the article in "The Log Book" that the addition of air from
a small blower in that chamber eliminated all the smoke from the firing, the
blower being used while the kiln was being stoked. The addition of a
catalytic converter between the ware chamber and the sutema would serve only
to re-burn any particulates still in the flue gases, and might eliminate the
need for the blower once the converter is up to temperature (around 400F).
Keeping the catalytic converter in the ware chamber allows one to take
advantage of the heat generated to add to the heat from the fire. I note
that many people have mentioned that the back of their kiln is cooler than
the front. This might help eliminate that disparity to some degree.
There have also been suggestions that pre-heating the combustion air by
piping it alongside or in the flue might help as well, and sealing the
firebox to accommodate the introduction of heated air would allow for
precise control of combustion, in effect turning the kiln into a giant "wood
stove".
Granted, this is certainly going to take a LOT more research. I see a large
increase in efficiency through less fuel used, as well as a strong reduction
in emissions possible from these modifications. I will continue to work on
it, and keep the list posted with any findings.
Best,
Wayne Seidl
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Ivor and Olive
Lewis
Sent: Saturday, November 11, 2006 1:22 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: LONGISH: Some thoughtsand questions on "smokeless" wood kilns
I think there is some confused thinking going on here.
The catalytic pollution control unit of an automobile is designed to deal
with the effluent created when a volume of petroleum reacts chemically with
a precise volume of air. At the temperature that this happens nitrogen in
the air becomes involves and forms one or more of the nitrogen oxides. These
are responsible for that great phenomenon "Smog". I am sure Wikipedia has
all the griff on this. Anyway, when the oxygen sensor responds and informs
the onboard computer, it takes care of the nitrogen oxides and the carbon
monoxide by bleeding air into the system. In a Potter's kiln the problem is
different. Control of combustion is imprecise. Ideally there should be no
smoke because you want to get all of the energy out of your fuel.
What is needed is a way to bleed air into the Stack without destroying
draught pull and have a small flame, or an electronic device there, to
ignite the wasted fuel once the two reagents have thoroughly mixed.
____________________________________________________________________________
__
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
______________________________________________________________________________
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Header Noack Repro on sat 11 nov 06
Hey Sandy:
Gas=clean burning, hence no collection chamber.
Wood=pizza oven...that would be in Ohio with Kelly.
LOL
Wayne
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Sandy Miller
Sent: Saturday, November 11, 2006 2:17 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: LONGISH: Some thoughtsand questions on "smokeless" wood kilns
For a guy who bisque fires his pots in his
self cleaning oven this is very impressive!
so just where is the collection chamber in
that self cleaning oven?
Sandy Miller
Des & Jan Howard on sun 12 nov 06
Ivor
Our 24 yo. woodstove doesn't have anything special.
When the flame from the firebox exits, it passes over a pipe
running from the outside through the flames, this pipe has
a slot cut into it, so, fuel rich flame mixes with superheated air,
this mix then passes into an after chamber through
~7 mm perforated steel plates that have a ~10 mm
sandwich of glass fibre batt.
A sutema at the back of the kiln entered via a chequered wall
with a forced preheated air supply should operate on the same principle.
Des
Ivor and Olive Lewis wrote:
>The only problem I foresee is the effects of impurities from your fuel. Catalytic systems are notorious for the ease with which catalytic materials can be inactivated. What do the makers say about their units?
>
>
--
Des & Jan Howard
Lue Pottery
LUE NSW 2850
Australia
Ph/Fax 02 6373 6419
http://www.luepottery.hwy.com.au
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