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

[Peter Davies]

James,

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.

Peter





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

-- 
Peter Davies
Director
ID Gasifiers Pty Ltd
Delegate River, Victoria
Australia
Ph: 0402 845 295

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