The Shelfords on sun 22 jun 97
Hi everyone, and especially woodfirers -
HELP! The environmental watchdogs here have decided that the Tozan
noborigama in Nanaimo, B.C. is putting out too much black smoke, and the
kiln will have to be shut down until we can install something to clean it
up. We did have some screens installed which were supposed to heat up and
burn off the carbon, but they didn't work. We also have a propane gas
burner in the bottom of the vertical chimney, but this too is not doing
enough. What are other kiln people doing? Does anyone have any experience
with this kind of problem? Any suggestions? We would appreciate anything
and everything you can throw at us. If we don't get some workable plans
going reasonably quickly, we'll have to shut down the remaining summer
firings at least, and possibly forever!!!!!!!
But if we can put together a reasonable plan of action, and get it started
at least, we might be able to apply for a variance to let us complete the
summer firings. The environmental inspector is not anxious to close us
down, but this is not a technology he knows anything about, so he has no
suggestions. There will be a meeting with him on Thursday, and we will be
presenting various ideas at that time. We've thought about higher chimney
stacks, burning smaller wood to get a hotter faster burn (but this won't do
anything for the reduction cycle) - stuff like that. Has anyone any quick
(but NOT dirty) solutions? PLEASE HELP!
Thank you thank you thank you
- Veronica
____________________________________________________________________________
Veronica Shelford
e-mail: shelford@island.net
s-mail: P.O. Box 6-15
Thetis Island, BC V0R 2Y0
Tel: (250) 246-1509
____________________________________________________________________________
Cindy on mon 23 jun 97
Veronica,
I've just been reading Nils Lou's book, The Art of Firing. I don't know
anything about wood firing, but according to his explanations, the thick
black smoke stage actually impedes reduction. Maybe you could reduce less
and get just as good or better results?
Cindy
Veronica wrote:
> HELP! The environmental watchdogs here have decided that the Tozan
> noborigama in Nanaimo, B.C. is putting out too much black smoke, and the
> kiln will have to be shut down until we can install something to clean it
> up
We've thought about burning smaller wood to get a hotter faster burn (but
this won't do
> anything for the reduction cycle)
Karl David Knudson on mon 23 jun 97
On Sun, 22 Jun 1997, The Shelfords wrote:
> ----------------------------Original message----------------------------
> Hi everyone, and especially woodfirers -
> HELP! The environmental watchdogs here have decided that the Tozan
> noborigama in Nanaimo, B.C. is putting out too much black smoke, and the
> kiln will have to be shut down until we can install something to clean it
> up.
Try installing a small blower at the base of your flue. We use an old
blower off an alpine forced air kiln and it makes a marked improvement in
opacity. This works best though only when the kiln is HOT. To lessen
smoke at eariler stages use the blower in conjunction with a burner. It
may also help to add something to the base of the flue to heat, ie a loose
stack of fire brick. the gasses from the kiln then pass through the hot
bricks and into the excess air from the blower.
Karl
Lauren BAll on mon 23 jun 97
Veronica,
All of the things you mentioned that you have tried should help a
little. But.. you need to mix a lot more air into your stack. Suggest
using a forced air blower, going in to the same chimney port as your
propane burner. Three things will happen. 1. you will burn more of the
smoke that comes from your kiln during reduction. (A taller stack will
help with this process giving more time for more complete combustion.)
2. It will dilute and speed up the smoke coming out of the kiln making
it much less visible. 3. It will also cool down the the chimney which
can get overheated from the heat from the screens, the propane burner
and the combustion of the smoke. If measurements are taken at the top
of the stack the percentage of unwanted material is acceptable. Some
cars use similar techniques. They put out near the same amount of
pollutants but because they are mixed with air before being exhausted
the measuring devices tell them that the Percentage is much less.
The Shelfords wrote:
>
> HELP! The environmental watchdogs here have decided that the Tozan
> noborigama in Nanaimo, B.C. is putting out too much black smoke, and ________
Gregory F. Wandell on tue 24 jun 97
Veronica
Air quality, global warming and pollution are important issues -- for
all of us. I think that the days of unrestricted wood firings are
slowly closing and being on the leading edge of change can be
difficult. The trick now is to adapt and change what we are doing to
live with the restrictions. In all honesty, I do not think that there
are any easy and cheap solutions. It will be a pain (as it already is),
but I am sure that you will find a workable solution.
Before you take my views as gospel truth, I should point out that I am
not an expert, but someone who has been in the environmental and energy
field for a while, and has picked up a lot of information and knowledge
via osmosis. And a woodfire wanna be.
Here s some thoughts:
The emissions from a wood kiln can be characterized (broadly) in two
ways, visible particulate matter (PM10) and combustion gasses. When you
fire with wood, visible particulates are emitted -- unburned fuel, fly
ash, etc. The other emissions are combustion gasses -- CO, CO2, NOx,
SO2, H2O, etc. It would seem that the inspector is only concerned with
PM10. However, it would be a good idea to gauge where the emissions
standards are headed, what restrictions may be placed on you and act
accordingly. At some point, after you fixed the PM10 problem, the
inspector might be back with instruments to measure the emissions of
combustion gasses as well. This issue isn t something you want to deal
with piecemeal.
What I would suggest is this, go to your friendly neighborhood
coal-fired power plant and ask them how they deal with fly ash and
combustion gasses and see if there is anything applicable to your
situation. Experts deal with these issues on a daily basis. In addition
to stares and puzzled looks, you might get several answers. Two
technologies you might inquire about are Electrostatic Participators
(ESPs) and hi-temperature ceramic filter bags. Even if these are not
the answers, their combustion engineers are trained to solve these
issues and may be willing to help.
ESP s are devices that generate an electric field and cause the fly ash
to become charged as it exits the flue and then drops out to be
collected. (I am positive my description is inadequate and full of
holes, but it is all I could think of at the moment.) At best, I would
think that this would be a partial solution.
The other possible solution are ceramic filter bags. These are
glorified vacuum cleaner bags designed to filter PM10 (Particulate
Matter greater than 10 Microns) at high temperatures. The only
technical problem I could easily see in this application (and I am sure
I don t know them all) would be the temperature of the gasses exiting
your
chimney. I don t recall what temperature they operate, but your flue
gasses may be too hot for this application.
You might also check out energy trade publications, organizations and
associations; universities; governments; etc.
I hope I was able to provide you with something you could use. Good
luck!
Gregory F. Wandell
Bethesda, Maryland
stevemills on wed 25 jun 97
Hi
Thoughts:
1)The passage of the fire may be restricted by too narrow
a chimney, previous Kilns in my experience (admittedly
limited) were somewhat smokey (understatement) current version
has a wider chimney, same length, burns much cleaner.
2)Are you overstoking? very easy to do in the quest for
reduction, let the Kiln tell you how much fuel it needs,
sounds "cosmic" I know but it works. Hardwood burns hot and
relatively clean, pine and similar reduces without trying
but keep it VERY thin, too big or too much overloads the
firebox, result= SMOKE. Little and often!!
Steve.
(copy to Clayart)
In message , The Shelfords writes
>----------------------------Original message----------------------------
>Hi everyone, and especially woodfirers -
>
>HELP! The environmental watchdogs here have decided that the Tozan
>noborigama in Nanaimo, B.C. is putting out too much black smoke, and the
>kiln will have to be shut down until we can install something to clean it
>up. We did have some screens installed which were supposed to heat up and
>burn off the carbon, but they didn't work. We also have a propane gas
>burner in the bottom of the vertical chimney, but this too is not doing
>enough. What are other kiln people doing? Does anyone have any experience
>with this kind of problem? Any suggestions? We would appreciate anything
>and everything you can throw at us. If we don't get some workable plans
>going reasonably quickly, we'll have to shut down the remaining summer
>firings at least, and possibly forever!!!!!!!
>
>But if we can put together a reasonable plan of action, and get it started
>at least, we might be able to apply for a variance to let us complete the
>summer firings. The environmental inspector is not anxious to close us
>down, but this is not a technology he knows anything about, so he has no
>suggestions. There will be a meeting with him on Thursday, and we will be
>presenting various ideas at that time. We've thought about higher chimney
>stacks, burning smaller wood to get a hotter faster burn (but this won't do
>anything for the reduction cycle) - stuff like that. Has anyone any quick
>(but NOT dirty) solutions? PLEASE HELP!
>
>Thank you thank you thank you
>
>- Veronica
>____________________________________________________________________________
>Veronica Shelford
>e-mail: shelford@island.net
>s-mail: P.O. Box 6-15
> Thetis Island, BC V0R 2Y0
>Tel: (250) 246-1509
>____________________________________________________________________________
>
--
Steve Mills
@Bath Potters Supplies
Dorset Close
Bath
BA2 3RF
UK
Tel:(44) (0)1225 337046
Fax:(44) (0)1225 462712
Hiro Matsusaki on thu 26 jun 97
I saw, four years ago, an anti-pollution device in a Noborigama at Shigaraki
Ceramic Center (Togei no Mori), which was mostly designed for public display
and not in frequent use at all. I thought it was stupid since it was not a
working kiln, and since its location was on top of a hill, far away from the
populated areas or the main buildings of the center. I really do not know the
truth, since I thought that was what it was. I did not have time to verify
this observation of mine. No one from the Center was around nearby. I was all
alone. But the government obviously thinks otherwise. More stringent
anti-pollution laws of all sorts are taking effect in Japan, anyway.
The device, I think, was basically an inline fan at the exit of a large
after-chamber which expands the flue gas to be coooled down with fresh
outside air. From this observation I got an idea to equip my own
milti-chambered kilns with exhaust fans to cut down on salt pollutants and
increase the fuel efficiency (since it was an indoor one and not climbing as
it should), and explained this to some fellow potters and teachers by snail
mail. I quoted the pull rather than the push effect to justify my thinking,
and backed up the argument with the Japanese woodworking tools (saws and
planes, for example) which often work the opposite direction, i.e., by
pulling rather than by pushing. Those tools are world class, the best money
can buy today, noted for their fine performances, as compared to the western
tools. More controls possible. I know more about those, but the basic idea is
sound, since I tried both ways. I can find those writings in the old CPM-80
machines that I still keep. (Bt the way, there is a definite trend to make
the web more of a pushing or pulling system, to improve the efficiency,
depending on your definition of the word. Things are changing there, too.)
The design of the fans and use of such devices are specific to my own
situation, and cannot be generalized. But the Shigaraki kiln reflects such a
refined but rather simple thinking, I am sure. It is strictly for
anti-pollution.
The basic idea to control the black smoke can be as follows.
1. The carbon is the main culprit of the black smoke. It comes from the
reducing fire. You can reduce (no pun intended) the period of such fire, and
do so during the darkest part of the night. Time your reduction to coincide
the wee hours when the inspector is not around. This solves most and
hopefully all the problems you seem to face right now.
Many coal burning power stations belch out the polluting smoke on weekends.
So are the cement plants. The wood burning sawmills operate at full capacity
burning waste wood pieces at the New Year's holiday season, to dispose of
their undesirables. I saw this happen, personally. It was awful, the entire
valley for hours of driving were filled by the stinking white smoke, but
nobody was there. I thought a forest fire was going on somewhere. The sun was
faint yellow. It was that bad. Hours on end, it seemed to me. Till I nailed
the real culprit. At such times there are no one to inspect or receive
complaints. Got the drift?
2. The reduction period can be adjusted. Never try strong reduction when the
temperature must climb. Use moderate one throughout, until a desired, certain
temperature is reached. I assume you do this reduction "adventure" at night
when the inspector is not around. No one would be wiser. It is stupid to
waste the fuel (wood) before you reach the temperature. In your case, do
continue the practice even afterwards. Moderate reduction is the key. Most
potters in America prefer strong reduction, for whatever the reason, I have
observed. In contrast, the traditional Japanese potters I know use the
balance, discretion and moderation in their firing schedule. The fuel or wood
is expensive over there.
3. Modify your stack or exhaust holes for your kiln, so that the exhaust gas
would get oxidized further. This requires an intelligent modification of the
structural arrangement of the kiln. You may have to use the oxyprove or other
devices, instead of the more reliable eyballing method, due to this change in
the kiln, since your exhaust smoke may not tell you the conditions in the
kiln, hence you have to resort to alternate methods. Right? Barring that, try
experimenting on a smaller scale before making a wholesale change, if you
want to proceed slowly and judiciously.
4. If you want a high-tech solution and do not wish to change the firing
schedule, for whatever the reason, I suggest that you simply blow in
additional air (oxygen) to the smokestack of the noborigama. Usually, this is
easy to do, since there are no elaborate stacks to increase the draft for
noborigama or anagama -- just open holes or a short stack. If it works, this
low-tech solution makes sense. The carbon burns off at a relatively low
temperature. Other pollutants do not. But you are not burning off the PCVs
under pressure. You do not have to.
4. How you blow in the air without creating the backdraft is the problem I am
working on right now. So, if you find an engineering answer, please let me
know. Adding extra volume of air, like ten times as much as the exhaust gas,
at a slightly lower velocity, should not only lower the exhaust gas
temperature, but also help pull the gas out of the kiln, instead of pushing
it back. Anyway, that's the way I see it. Theoretically, at this stage, at
least.
5. For your meeting with the inspector Thursday. Explain that you have
revised the method of burning wood. Will make it burn clean, like garbage in
backyard drums. Do not go into any technical details. You will use the
experienced "burner" and not novices. The more information you give, the more
holes he or she will try to find. And despite the assertions to the contrary,
that person should know the business inside and out. The garbage talk should
satisfy him. Anything more, you invite troubles. No numbers, please. Just
tell that you will burn the wood clean, and watch out for any stupid novices
burning it black. That is all. Meantime, experiment on the black smoke
business only when the color cannot be seen. Your firing schedule should be
in oxidization to neutral druing the day.
I hope this works out. Never tackle an entrenched bureaucracy. Or, try to
outwit it. You never win. Conversely, do not commit yourself to any
improvements. Just change your habit, or the polluting firing habit. Like our
eating habit, it is hard to change what we have been used to do, but for the
health of the industry, it may be the thing to do. For now, that is my
advice.
I lost my beta version of the software, and hence had to retype my messages
all over again, in addition to have the old version back in shape. Hence the
delay. I hope you find what I explained useful. HM.
Jack Troy on thu 26 jun 97
Re: Smokeophilia vs smokeophobia:
I am off the list more than I'm on it but I saw your "help" post, and thought
I'd reply.
The people at East Sydney Technical College, on the outskirts of Sydney, Aust.
have had a wood-burning kiln for years and have successfully burned off excess
smoke with a propane burner.
I note that you still have a smoke problem after installing a burner, and wonder
whether the the burner is too small and/or whether another burner might help.
Have you noticed _any_ difference in output when you use the burner? Do you
coordinate turning up the burner when you stoke? (I believe you'll need a
whopping good flame just after stoking).
How tall is your chimney, and what size is it? Did you model your kiln on
another? The name "Tozan" puts me in mind of a kiln at ASU in Flagstaff with
that name. If so, has there been a similar problem with the prototype, and has
it been solved?
I had lots of smoke from my anagama when I fired last time until I got to about
c/8, and then the chimney "kicked in" (meaning it reached a temperature which
really improved the draw, and the smoke output from then on was much less. So
I'd suggest getting your propane burner(s) going early on to heat the chimney,
and the flue area as well, and not let that happen solely as a result of the
firing itself. BTW, is there a horizontal flue leading into the chimney? I'd
have the burner(s) located at the kiln-end of it (as opposed to the chimney-end)
if possible.
And yes, the size of the wood you're stoking is important - the smaller and
drier the better, which means more vigilant stoking patterns (i. e. more
attentive work by all participants, especially during daylight hours, which, for
better or worse are many this time of year). You _can_ achieve the reduction you
seek if the timing of your stokes and the number of pieces of wood you stoke are
carefully balanced to provide heat gain and periodic reduction without excess
smoke at the chimney. (And, sorry, I must decline in advance any offer of even a
first-class ticket to monitor this activity...this is your baby; you planned the
parenthood; you alone can burp the little blighter).
I hope no one shuts your kiln down, but I also must ask whether the kiln-site is
one of high-visibility (near a town or place where it can be seen by many
people). I know this is somewhat beside the point, but as in real estate,
successful kilns often depend on three factors: location, location, and
location.
Best wishes, and keep in touch,
Jack Troy
Louis Katz on fri 27 jun 97
Please excuse me for not having read all of the Re:Nanaimo posts. I will
probably repeat some information from someone else. I read Jack Troy's
post and thought I would add my two cents.
My understanding of the afterburning of carbon soot is hat you need lots
of hot oxygen and that you need good mixing. If you are running a burner
in the flue it needs to have a big excess of air included with it and it
needs to have enough time and turbulence to mix with the exhaust from the
kiln.
It is also my belief that leaning towards using primary air coming thrugh
the wood in a wood kiln as opposed to secondary air mix with the gases
coming off the wood will help reduce the smoke, but this is conjecture.
Louis
Louis Katz
Texas A&M University Corpus Campus
lkatz@falcon.tamucc.edu
http://www.tamucc.edu/~lkatz
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