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Woodburning kiln emissions


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#1 justanassembler

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Posted 16 February 2013 - 01:09 AM

Can anyone point me to scientific data about the contents of wood kiln effluent? I know there was a presentation @ NCECA in '05 or '06 that touched on it, and I feel as though I read something in CM or Studio Potter at one point, but Im coming up blank when it comes to specifics....

#2 JBaymore

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Posted 16 February 2013 - 07:31 AM

I know there was a presentation @ NCECA in '05 or '06 that touched on it, and I feel as though I read something in CM or Studio Potter at one point, but Im coming up blank when it comes to specifics....


The NCECA presentation you mention might have been one that I did.

What exactly do you want to know?

best,

....................john
John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#3 justanassembler

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Posted 18 June 2013 - 01:49 AM


I know there was a presentation @ NCECA in '05 or '06 that touched on it, and I feel as though I read something in CM or Studio Potter at one point, but Im coming up blank when it comes to specifics....


The NCECA presentation you mention might have been one that I did.

What exactly do you want to know?

best,

....................john


Holy thread resurrection--sorry.
I was looking for particulate information, as well as carbon emissions in comparison to a similarly sized gas kiln

#4 JBaymore

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Posted 18 June 2013 - 09:27 PM

This kind of analysis gets really complicated if you are asking this question in trying to do a "better or worse" kind of comparison. That was one of my key points in the NCECA presentation. Too many "green" statements are very narrowly focused....and often highly misleading. The "big picture" is the only really accurate answer where you take ALL factors into consideration. To do this requires experts to look at it all. And lots of time and study (and hence money).

First of all..... WHO is firing each type of kiln, and HOW are they firing it? Those two factors alone can have a huge impact on "the numbers".

For example, in teaching situations I have deliberately taken a specific gas kiln and set it up firing in what would be an "appropriate" amount of reduction. Then I measured the levels with an Oxyprobe. I then had other people come in and observe the kiln VISUALLY for a while to "learn" the level of reduction happening using all the usual visual, auditory, and olefactory markers that potters tend to use for this. They could even see the reading on the Oxyprobe for that part. I then had them leave the room, and I mis-adjusted the controls to put the kiln into oxidation. I asked them each to then come back in and adjust the kiln VISUALLY to match the prior original condition (but no Oxyprobe available to them this time).

When they SWORE the kiln was set "the exact same way"...... I'd check with the Oxyprobe. The readings were ALL OVER THE PLACE. Some of these people were students... and some were facutly with MFAs and YEARS of firing experience. Some people's settings would have produced less CO and less particulate C ...... and others produced more. (Yhis is also what people often get "surprises" when they open the kiln.)

WHAT is the kiln design? There is another HUGE factor. Some gas kilns have very really lousy combustion systems on them and very poor in-chamber mixing. Others are "state of the art". Each would provide different answers for you... and STILL would be tempered by WHO is firing then amd HOW.

Some wood kilns have very efficient aeration and mixing...and some are literally still 15th century technology. Each would priovide you with completely different answers. There is a noborigama in Japan that has full industrial scrubbing........ fires as clean as a whistle.


To generalize (which makes this answer wrong in 99 percent of cases), PM 2.5 and PM 10 for a wood kiln is significantly higher than for a gas kiln. But on the other hand if you look at a 30 year cycle period, wood kilns are carbon neutral if replacement trees are being grown while gas kilns are greenhous gas producers.

Periodic studio type electric kilns are HORRIBLY polluting when looked at in the "big picture". They are NIMBY units when people think of them as "clean". They have a chimney.... it is located at a centralized power plant. Centralized electric generation and transmission is very lossy.... inefficient use of fuel. Coal is contaminated with mercury. Those types of kilns are typically underinsulated. They are also small and have large surface to volume ratios... so the heat energy used to heat up the kiln structure as a ratio to the heat energy used to heat the wares is TERRIBLE. I could go on.

Name your poison.


best,

....................john
John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#5 justanassembler

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Posted 19 June 2013 - 12:28 AM

Thanks--that was actually the sort of answer I was looking for--I appreciate your candor and experience--you're an asset here, for certain.

#6 Kohaku

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Posted 19 June 2013 - 02:44 PM

Name your poison.
best,

....................john


Very lucid, balanced answer to a tough question.

The only thing I'd question a bit (I got into a discussion with a student about this the other day- so it's fresh on my mind) is the notion that wood-burning is carbon neutral if trees are replanted... (you could theoretically make the same case for burning natural gas)... but you do a nice job of acknowledging the complexities even there.

Is your 2006 presentation available online? I'd be interested...
Not all who wander are lost

#7 JBaymore

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Posted 19 June 2013 - 03:39 PM

Kohaku,

Thanks for the nice words Justin and Kohaku.

Unfortunately no, it is not. NCECA videotapes or audiotapes all of the presentations (or it seems that way from the four that I've done over the years) but I have no idea what happens to them. They just seem to mostly disappear... other than the demo ones that eventually show up on DVDs for sale.

Yeah.... natural gas is pretty much also carbon neutral ........if you look at "geologic time" as the referent.

The complexity of the issue in accurately evaluating the impact of our firing operations is huge. Other factors that no one tends to think about includes various factors like.... if potter A builds a kiln with firebricks made in say.... Georgia. And potter B builds the SAME exact kiln with firebricks made in Georgia......... BUT potter B is located in California and potter A is located in Florida........ what is the carbon impact of the shipping of the heavy bricks (likely by truck) across most of the country?

Or... if Potter A fires an electric klin in New Hampshire and Potter B fires the same electric kiln in Oregon....... it is likely that the sources of the electricity used are balanced differently. Maybe Oregon utilizes more hydro power while NH uses more nuclear. So potter B is more "green" than potter A.

And the REALLY BIG thing in this whole "let's practice green pottery" thing that seems to be becomming a "fad" lately, and a HUGE focus of my NCECA presentation, was that compared to the OTHER things that most of us do in our lives, our pottery operations are likely a MINOR inmpact on the environment.

I did a detailed analysis of the fuel consumption and pollutant operation of the engines on the Boeing 747 (I'm a bit of an avaiation nut) and the same kind of analysis of the operation of my noborigama. I do not remember the exact numbers right now (I have them somewhere) but if I am remembering correctly it came out that I could fire my large wood kiln repeatedly in a year for something like 80 years on the equivalent of a single one-way 747 flight from NY's Kennedy Airport to Narita Airport (New Tokyo International) in Japan. (THINK about how many aircraft of all types are in the air around thwe world as you read this.)

If people (potters) want to REALLY be environmentally friendly.... don't switch from cone 9 to cone 6....... lose the gas guzzler car, insulate your house, walk or bike ride when you can, use mass transit, stop buying crap made in China and shipped accross the world, eat local produce instead of stuff shipped in from South America, and so on.

Heck... I even took a "shot" at NCECA on the big picture environmentally. Look at the massive environmental impact of all the potters traveling into the conference locations from around the States and the world....... and the support of them in the hotels and restaraunts and other places......... HUGE.

best,

................john
John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#8 Wyndham

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Posted 19 June 2013 - 04:14 PM

John,
I'm not disagreeing with you or others; and without going too far afield, the balance sheet on carbon also has to include the jobs and businesses and livelihood of people that are benefiting from the air traffic, the conferences, the potters standard of living and such as that.
Yes there is a personal responsibility to be good stewards of our earth but that also includes allowing people to attain a reasonable/ equitable standard of living , which I believe is also be good stewards.

Just a different POV.
Wyndham

#9 Frederik-W

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Posted 20 June 2013 - 06:15 AM

Very good answer.
People need to be reminded that electricity (which usually comes from coal) is not clean - as you say: the chimney of the power station is just somewhere else.
Wood firing can actually be very efficient.





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