[Gasification] Dioxins ...was Clean air ..

James Joyce james at jamesjoyce.com.au
Sun Jul 6 05:47:06 CDT 2014

Hi Peter and Leland. Thanks for your replies. 

What you say Leland about reducing conditions is probably good news for those in the torrefaction game as well as those running downdraft systems. In our case we are running a continuous updraft rotary hearth gasifier, so it is a much different animal than a downdraft. I am not really sure what the oxygen levels are in the hearth itself as our analyser cannot measure oxygen when the CO level is above 5% ... which is most certainly is in the hearth. It is also mostly greater than 600 deg C in the hearth, except where the feed comes in ... which should help too.

Peter, ultimately if NSW prove intractable, which it is too early to say, we will just focus elsewhere ... life is too short as they say.

I have found that there are compliance (hi resolution) and screening (low resolution tests), collected in Australia but sent to Belgium for analysis. Those options allow more datapoints to be collected to help in forming a case for the EPA. At this stage we are not looking for compliance level testing .. we just want to know whether we are likely to have an issue or not. 




Date: Mon, 30 Jun 2014 07:21:02 +1000
From: Peter Davies <idgasifier at gmail.com>
To: gasification at lists.bioenergylists.org
Subject: Re: [Gasification] Dioxins ...was Clean air ..
Message-ID: <53B0833E.7040305 at gmail.com>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"


I liked Kevin & Doug's wise replies. As you are aware from our personal discussions we covered this issue at some length with the NSW EPA at their invitation back in 2013. The core issues have not changed and you remain definitely up against it. What you are experiencing now is the reason we opted for a hybrid plant that uses our gasifier to manage emissions, designing and building the pyrolysis section ourselves now since no one with existing working designs believed the approach we offered was necessary.

The EPA did warn the emerging pyrolysis industry that their apparent belief that they could apply sufficient political pressure to have the regulator water down requirements would fail, and that companies would need to address the issues rather than expect to be able to ignore them.  As you will be aware even those who have enjoyed considerable Government largesse over the last decade, recieving millions in public monies, are not exempt from this hence why they are big on press releases but non existent on working commercial projects.

Your a)....d) point list is why the NSW draft waste to energy policy issued started with prescriptions based on combustion incinerators. We successfully argued against this since it precluded approaches other than combustion as a suitable technology, and the final release version recognises this by setting targets rather than prescribing things like minimum combustion zone residence times, allowing then for innovation in the private sector as to how best to meet the requirement.

Essentially though it is recognised that pyrolysis systems _can_ operate under conditions that encourage dioxin and other nasties or result in above background level release. You can argue till you're blue in the face that yours doesn't, but at the end of the day you have to prove it. 
The onus is on you to do so, not the EPA to prove you are. Then you have to follow up and confirm it still isn't later on down the track after you have been operating for a bit, and then every time someone with little knowledge and a lot of fear (or simply penchant for stirring trouble, like jealous competitors) lays a complaint that you might be. 
The upshot being you will need to budget for more than one expensive test...and any licensing granted is only on a project by project basis.

We were invited to apply for a General Exemption for our own system as they are satisfied that our plant design could inherently satisfy the legislation, we have not followed through yet simply because this too still has confirmation testing and costs associated, is scale dependent, and has to be repeated for each feed stock change (Cotton gin trash vs woody wastes from composting operations for example) so we see it as part of the client expense in the first instance, and secondly the most likely path for us is offshore due to continued seemingly Government backed attempts to misappropriate our IP for the benefit of some of their mates. I don't say this lightly either, it is currently the focus of a formal fraud investigation.

$3000 per sample seems on the low side of quotes we had, $5000 being the norm. $10,000/day is the cost for a independent technicion to come to the plant for the same purpose. Any hint, real or perceived, that you might have fudged the sampling whilst doing it yourself can prove very, very expensive, particularly where the results are not accepted and you have to get independent qualified testers involved, who then come up with adverse results... Hence why established industry opts for the independent testing route in the first instance. As an aside this is also the reason we have a properly engineered gas sampling column to ensure representative samples built into our latest 500kg/hr industrial scale gasifier module, it has already been noted by visiting scientists/engineers as "uncommon practice" but "very smart" (the same scientists who after the demonstration also recommended we stop calling it a gasifier, not because it isn't, but because the association with standard industry expectations of performance does it a grave disservice).

Assuming you successfully negotiate the testing, don't forget you will also need to demonstrate how you can address shoddy or uneducated users of your plant changing the operating parameters or allowing in problematic feed stocks that increase the risk of exceeding the emission limits.

Good luck.


On 30-Jun-14 4:00 AM, gasification-request at lists.bioenergylists.org wrote:
> Message: 3
> Date: Sun, 29 Jun 2014 07:48:07 +0000
> From: James Joyce<james at jamesjoyce.com.au> 
> To:"gasification at lists.bioenergylists.org"
> 	<gasification at lists.bioenergylists.org>
> Subject: Re: [Gasification] Dioxins ...was Clean air ..
> Message-ID:
> 	<4C71E96F48AF454D99A0EAE2C116A34A5732721F at MBX-002.ezyexchange.net.au>
> Content-Type: text/plain; charset="us-ascii"
> Leland, regarding costs. I have had two scenarios described to me, one where the sample device is provided and I take the sample (therefore up to me to make that representative) and one where a technician comes in to collect the sample. I believe the $3000 applies to the first case ... ie. sampling is an additional cost.
> If you are referring to on-line or at-line GS-MS or Gel chromatography I am interested to hear about experiences with these techniques. Our plant operators are not qualified instrument techs or lab techs ... which means at best the devices would get a check over on a monthly basis during scheduled plant visits.
> My interest in the bag filter was with respect to particulates. This relates to dioxin in that they tend to be adsorbed onto the particulates (although perhaps more so at <300 deg C than 600 deg C), so it is one way to remove dioxins and their precursors if they are present. Some plants I understand actually inject fine carbon into their flue gas for this very purpose.
> Kevin, on your comments about Chlorine and copper, I have been maintaining a watching brief for some time on the topic and from what I understand Chlorine levels are in fact poorly correlated with Dioxin emissions, arguably because the chlorine levels in most feedstocks, even at ppm levels are many many times the quantity needed to make the tiny amounts of Dioxins that regulators are checking for.  I read a very good review of the science just last week. If anyone wants the reference I could dig it out next week. The review of a looked critically at a variety of data on Dioxin formation and control. My interpretation of the their conclusions is that Dioxin emissions from pyrolysis, gasification and combustion processes are:
> (a) Very poorly correlated with Chlorine levels, with the exception of 
> a few industrial chemicals (not biomass)
> (b) Strongly correlated to completion of combustion and the residence 
> time of flue gases between 200 - 400 deg C (the desired residence 
> times in this range were less than 1.6 seconds ...which perhaps does 
> not bode well for torrefaction ! ... and hot running electrostatic 
> precipitators)
> (c) Catalysed by copper and copper compounds .. which in turn are inhibited by the presence of sulphur.
> (d) Sometimes dictated by the dioxin content of the incoming feedstock 
> rather than formation in the process
> If anyone has done Dioxin measurements on flue gases from thermal processing of biomass I certainly would be interested in their experiences.
> Regards,
> James



Message: 2
Date: Sun, 29 Jun 2014 20:03:24 -0400 (EDT)
From: linvent at aol.com
To: gasification at lists.bioenergylists.org
Subject: Re: [Gasification] Dioxins ...was Clean air ..
Message-ID: <8D1620DD85488C9-128C-26641 at webmail-d283.sysops.aol.com>
Content-Type: text/plain; charset="us-ascii"

	We have had extensive testing done or dioxins on MSW/RDF gasification and in the critical critical areas, did not ?have detectable levels. The third party work was done by Los Alamos National Labs, San Diego's consortium of waste management, ?Sandia National Laboratories and Radian, the same technician/engineer for Radian that prepared an exhaustive analysis for DOE that was the technical basis for US ?EPA to try to get refinery waste gasification exempted from RCRA, but hasn't happened yet.?
	A technical evaluation of gasification shows that without oxygen the basic reaction of Cl+O2->ClO2 doesn't occur and hydrogen will strip the O2 from chlorine compounds already formed, preventing he dioxin formation and breaking down any dioxins introduced to the system. This has been discussed here before.?
	?A GC cannot be used for metal analysis, at least none of the ones I have been exposed to.?
	Not using a qualified technician may allow the regulators to throw out the results.?
Leland T. "Tom" Taylor
Thermogenics Inc.?

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