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, [email protected] wrote:
Message: 3
Date: Sun, 29 Jun 2014 07:48:07 +0000
From: James Joyce<[email protected]>
To:"[email protected]"
<[email protected]>
Subject: Re: [Gasification] Dioxins ...was Clean air ..
Message-ID:
<4c71e96f48af454d99a0eae2c116a34a57327...@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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