[Gasification] Hazardous classification of MSW, plasma gasification thermodynamics

[linvent at aol.com]

GAsification produces an ash where the RCRA hazardous metals are bound 
and inert,  and pass US EPA TCLP leachate test which means that it can 
be put into landfill. I am not sure how MSW can be classed as a 
hazardous waste as per your language Peter. Otherwise normal landfills 
would also accept hazardous waste. Metals volatilized in a normal 
gasifier are condensed in the lower temperature section of the gas 
processing. In plasma gasification they would coat any nearby cooler 
surface very rapidly, leading to potential blockage in short order. The 
amount of energy put into plasma gasification is a waste of energy as 
all of the desired reactions occur at much lower temperature and it 
makes no thermodynamic reason to go above those temperatures. Ash 
vitrification in plasma is supposedly better, but the lower temperature 
and hydrogen environment of a regular gasifier produce a stable TCLP 
ash anyhow.
There are direct methods of measuring metals in a gas stream. There is 
an interesting study where the metal balance in a gasifier is attempted 
to be determined but couldn't. More went in  than came out and where 
the difference occurred was never determined.
Sincerely,
Leland T. "Tom" Taylor
President
Thermogenics Inc.

-----Original Message-----
From: jonathan <jonathan at bmpconsultants.com>
To: Discussion of biomass pyrolysis and gasification 
<gasification at lists.bioenergylists.org>
Sent: Sat, Feb 11, 2012 7:39 pm
Subject: Re: [Gasification] Steam Turbines

We can provide custom turbines; if you will forward your requirements 
I'll provide you with a quote.

Thanks,


Jonathan

On Sat, Feb 11, 2012 at 3:58 PM, Peter & Kerry 
<realpowersystems at gmail.com> wrote:
Hi Liran,

The 2 second combustion requirement is an Interesting and slightly 
disturbing prescriptive regulator response (that narrows gas use 
options), is somebody in authority just guessing and being cautious or 
is it based around actual gas analysis results from your plasma 
gasification system?

What potential constituents in the gas stream are these requirements 
aimed at?

In regard our own experience with gasifying hazardous waste (sewerage 
sludge with potential heavy metal contaminants, particularly mercury & 
cadmium) the client at the time for this (a large public authority) 
would not pay for direct emissions testing covering these so we paid 
out of our own pockets for an indirect "indicator" measurement, getting 
a ultimate analysis of the raw feed stock and the same test on the ash 
collected from the test run, then had a industrial chemist review the 
results. This showed the metals identified in the original analysis 
were captured within the ash in equivalent amounts relative to the mass 
reduction from the original sample (so didn't travel out with the gas).

Is this a problem with Plasma gasification? Are such contaminants 
mobilised in the gas instead?

We are currently engaged in the early stages of a formal testing 
project involving MSW and other hazardous wastes that will have EPA 
oversight and permitting for the trial. The results from this will 
inform pilot commercial scale system design and operating parameters in 
regard to emission management for our own system, so we are interested 
in what other regulator agencies are thinking in regard general 
gasification issues that might be flagged along the way.

Otherwise we would agree with Pannierselvam's question. Certainly 
subject to your gas meeting all the requirements for gas turbines (not 
just energy content) then these combined with downstream HRSG steam 
units using this exhaust, perhaps augmented with some  auxiliary firing 
if needed, could be another way to meet your regulatory requirement.

At the moment we are unaware of any commercial fuel cells that wouldn't 
require a high level of gas polishing and separation without quickly 
poisoning the cell, but also would love to hear more.

Regards,
Peter

Peter Davies
Real Power Systems Pty Ltd
Australia


Steam Turbines

Liran Dor liran at eer-pgm.com
Sat Feb 11 13:26:27 CST 2012
Previous message: [Gasification] Steam Turbines
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Dear Pannierselvam,

Thank you for your reply

The reason for the rankin cycle is that due to the fact we are treating 
hazardous waste the environmental regulation dictate we combust the gas 
in a chamber with a 2 second residence time.

I do like your approach for the MSW application we are working on and 
would like to hear more about it.

Thanks

Liran


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