H2S Corrosion Protection?
Mand...@worldnet.att.net
H2S corrosion? And why? Thanks
Mitchel
William R. Penrose
>Can anyone suggest a good component to use for protecting metals from
>H2S corrosion? And why? Thanks
Several companies will coat metal parts with Teflon. This treatment
is very effective against nearly every corrosive gas.
What metals are you using? Some are not bothered by H2S.
H2S in a gas stream can be removed by oxidation on Purafil
(www.purafil.com) or by absorption into copper sulfate solution.
Bill
L. Smith
I don't totally agree with you.
A lot of work was done by the National Association of Corrosion
Engineers regarding coating of metals for H2S protection, and it is not
the cureall that one might suspect.
I remember Taylor Hunt of NACE telling me of work to be published in
which coatings were applied, and then machined to varying thicknesses
so that the effect against corrosion could be measured. Guess where
the failures occurred - in every case.
Corrective measures depend heavily upon the system, and on the mode
of attack which is occuring; i.e., pitting, blistering, hydrogen
embrittlement, stress corrosion cracking, etc.
Both oxidative and non oxidative sulfide scavengers are available.
Copper sulfate is a bad idea from many standpoints, although undoubtedly
it would react with sulfide.
--
- Larry Smith
----DON'T RETURN EMAIL TO ME----
until you check my address for spam-wedge
William R. Penrose
<LARspam...@ONLINE.NO> wrote:
>William R. Penrose wrote:
>>
>> On 26 Nov 1998 02:30:56 GMT, Mand...@worldnet.att.net wrote:
>>
>> Several companies will coat metal parts with Teflon. This treatment
>> is very effective against nearly every corrosive gas.
>
>I remember Taylor Hunt of NACE telling me of work to be published in
>which coatings were applied, and then machined to varying thicknesses
>so that the effect against corrosion could be measured. Guess where
>the failures occurred - in every case.
Good point. I suppose that Teflon, being as permeable as it is, would
let H2S in to get at the metal, if the concentration was high enough.
We used Tef-coated aluminum and brass fittings for years with low
concentrations of H2S, typically under 50 ppm. Without the coating,
brass fittings showed corrosion in very short times.
Bill
Tapio Hurme
William R. Penrose
wrote:
>Try glass coatings. At least it works!
I'm curious. How do you do this?
Charles B. Schroebel
> Can anyone suggest a good component to use for protecting metals from
> H2S corrosion? And why? Thanks
>
> Mitchel
>
>
>
How about Duralloy High Si Steel? (weel, almost a cast iron, matter of
fact you shouldn't machine it unless you take real precautions from the
dust!) good against hot H2SO4. Thompson's will lead you to a source.
charles schroebel
box 1205 baltimore, md 21203-1205
csch...@umaryland.edu
geht noch ein?
noch ein geht immer noch!
Wenn im Sommer heiss und trocken
muss man dick am Zapfhahn hocken!
all opinions expressed here are my own and
due consideration should given that fact.
L. Smith
>
> On 26 Nov 1998 Mand...@worldnet.att.net wrote:
>
> > Can anyone suggest a good component to use for protecting metals from
> > H2S corrosion? And why? Thanks
> >
> > Mitchel
> >
> >
> >
>
> How about Duralloy High Si Steel? (weel, almost a cast iron, matter of
> fact you shouldn't machine it unless you take real precautions from the
> dust!) good against hot H2SO4. Thompson's will lead you to a source.
>
> charles schroebel
> box 1205 baltimore, md 21203-1205
> csch...@umaryland.edu
Do you know if this alloy is susceptible to embrittlement in H2S
service?
H2S can be nasty because it doesn't just caused a generalized corrosive
attack. In fact, general corrosion rates can be quite low, but the
occasional penetrating pit can put you out of business. If the part
moves in a cyclical manner, stress corrosion cracking can become a
problem.
Mettalurgy is of prime importance in designing a system for sour
service.
There are chemicals which can remove the H2S economically in some cases.
Also there are corrosion inhibitors based on film forming amines which
can give another measure of relief.
There are both pros and cons to protective coatings; namely, some of
them are not so protective, and poorly applied they may cause more of
a problem than they solve.
SNUMBER6
>H2S can be nasty because it doesn't just caused a generalized corrosive
>attack.
One method is bacteriological ... found in sewers throughout the land ... There
is this bacteria which eats H2S and poops shall we say sulfuric acid ...
converting the weak acid corrosion to a strong acid corrosion ..
In the Village ....
I am not a number ... I am a free man !!!!
L. Smith
Converson of H2S to H2SO4 certainly occurs in nature. It leads to
another type of corrosion in cast iron sewer pipe commonly called
"sulfatization" in some camps.
The pipe can look pretty much intact, but it becomes very brittle.
Some of the iron in the crystalline matrix of the cast iron has been
dissolved away, leaving a graphite-like structure.
If the oxidation does not proceed all the way to sulfuric acid, you
can produce elemental sulfur which deposits on the metal. In this case
you have still another mode of corrosion in which the elemental sulfur
becomes an element in a galvanic type of attack. To control it you may
have to remove the sulfur and this can be nasty and expensive.
L. Smith
> Converson of H2S to H2SO4 certainly occurs in nature. It leads to
> another type of corrosion in cast iron sewer pipe commonly called
> "sulfatization" in some camps.
*****This type of corrosion is more commonly called, I believe,
"graphitization", because the remaining structural material closely
resembles graphite. I think there was a slip between the brain and
the typing fingers in my post..