iandol on fri 6 apr 01
Dear Ababi,
I can understand your concern, since the destructive distillation of =
coal releases many noxious metals which evaporate at relatively low =
temperatures. But in the case of power stations which burn coal or =
lignite, I would think that the temperature of combustion is as high as =
they can make it so that all the energy is extracted. Therefore, such =
contamination should be minimal in the resulting ash.
Best regards and thank you for responding.
Ivor.
ferenc jakab on sun 8 apr 01
But in the case of power stations which burn coal or lignite, I would think
that the temperature of combustion is as high as they can make it so that
all the energy is extracted. Therefore, such contamination should be minimal
in the resulting ash.
Ivor,
In fact, unscrubbed power station emissions are extremely dirty and
polluting. The worst feature of Australian power emissions, Other than CO2.
are sulphur emissions for which the emission standards are much lower than
in the U.S..
Feri.
Joseph Herbert on sun 8 apr 01
You wrote:
"Dear Ababi, I can understand your concern, since the destructive
distillation of coal releases many noxious metals which evaporate at
relatively low temperatures. But in the case of power stations which burn
coal or lignite, I would think that the temperature of combustion is as
high as they can make it so that all the energy is extracted. Therefore,
such contamination should be minimal in the resulting ash. "
This is not entirely true. Workers cleaning power plant furnaces face
significant risk from arsenic, especially if grinding or welding on furnace
metal. They are required to receive training and wear protective clothing
to prevent ingestion.
Water wall furnaces, that have a suspended flame, actually have lots of
relatively low temperature surfaces where volatile metals can plate out.
Fly ash that leaves the furnace during active combustion probably has low
metal content but ash is deposited in various parts of the furnace and stays
there, exposed to volatile metal, until the furnace cleaning. This ash
could have very high arsenic concentrations. The problem is to tell which
ash you have. If you can tell which piles come from the bag house during
normal operation and which are hauled out during outages, you could probably
use the normal operation deposits.
Joseph Herbert
Ababi on mon 9 apr 01
Thank you Joseph. For me not knowing means the worst.One of the tests I made
with 3 or 4 copper oxide, gave result like if I made it with 10% copper
oxide, Shiny gray, made me understood that there is more than
Silica -alumina in what I called (for my own use)," Black Kaolin".
.....Ababi in the Northern Negev where still, hopefully forever pretty good
relationship between two nations
ababisha@shoval.ardom.co.il
http://members4.clubphoto.com/ababi306910/
----- Original Message -----
From: "Joseph Herbert"
To:
Sent: Monday, April 09, 2001 6:53 AM
Subject: Fly Ash. Metallic contamination
> You wrote:
>
> "Dear Ababi, I can understand your concern, since the destructive
> distillation of coal releases many noxious metals which evaporate at
> relatively low temperatures. But in the case of power stations which burn
> coal or lignite, I would think that the temperature of combustion is as
> high as they can make it so that all the energy is extracted. Therefore,
> such contamination should be minimal in the resulting ash. "
>
> This is not entirely true. Workers cleaning power plant furnaces face
> significant risk from arsenic, especially if grinding or welding on
furnace
> metal. They are required to receive training and wear protective clothing
> to prevent ingestion.
>
> Water wall furnaces, that have a suspended flame, actually have lots of
> relatively low temperature surfaces where volatile metals can plate out.
> Fly ash that leaves the furnace during active combustion probably has low
> metal content but ash is deposited in various parts of the furnace and
stays
> there, exposed to volatile metal, until the furnace cleaning. This ash
> could have very high arsenic concentrations. The problem is to tell which
> ash you have. If you can tell which piles come from the bag house during
> normal operation and which are hauled out during outages, you could
probably
> use the normal operation deposits.
>
> Joseph Herbert
>
>
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