On Mon, 7 Jun 2004 23:57:31 +0100, "Keith Willshaw"
wrote:


"Peter Skelton" wrote in message
.. .
On Mon, 7 Jun 2004 20:31:42 +0100, "Keith Willshaw"
wrote:


Gee I just said that

No, you blamed the accident on failure to anchor a bypass.

Which is functionally identical to what you posted.

Did you even read it ?

Yes, the functional equivalency is only at the level of escaped
material. This is not a crucial point, can we move on?

No we cant

The acident happened because when a Reactor was
taken out of service a bypass consisting of sections of pipe
and bellows units was put in its place. This rested on temporary
scaffolding and the load from the liquid slug ruptured the bellows.

http://www.cheresources.com/procacc.shtml






There was no automatic shut-off upstream. The plant lacked modern
process controllers[3] and was, even by standards of the day, not
centrally controlled.


Quite so , not that it would have helped much

It would have ended the fire within fifteen minutes.


Only if it were still functional after the initial explosion, given the
scale of the damage done by what was to all intents a 50 ton
FAE thats unlikely. The issue is moot however since the major
damage was done by the initial explosion

I doubt there'd have been an explosion of anythihg like that
magnitude.

There was , read the bloody report.

??????? There was? this is a sequence that did *not* happen. You
might argue that there would have been, but what you typed is
nonsense.

A lot of material had to leak fast.

It did, , read the bloody report.

See above

A leak of that
size should automatically close both the upstream and downstream
valves.


What upstream and downstream valves ?

We're talking here about the effect of valves that were not in
the system. Here's the important text, copied from above:
---
There was no automatic shut-off upstream. The plant lacked modern
process controllers[3] and was, even by standards of the day, not
centrally controlled.

----

The explosion was 15 tons equivalent of the BLEVE [1] type, the
fire lasted days becuase about 10% of the plant inventory had to
be allowed to burn out [2]. There was minimal effect past the
fence.


Wrong. Even though the explosion occurred on a rural site
53 members of the public received major injuries and
hundreds more sustained minor injuries. The plant was
destroyed as were several others on the same site and
close to two thousand houses, shops, and factories
were damaged with some 3000 residents being left homeless


No part of the plant met modern standards.

There are plenty of 1970's pterochem plants
still out there and the best control system in the
world doesnt help when you dump 50 tons of
Cyclohexane into the environment.

There aren't may fifties plants out there and there aren't any at
all that will dump fifty tons of cyane from a pipe rupture.


There are lots of plants built in 60's and 70's

Certainly. When was this one built?

You mean your sekrit info didnt include that fact ?

I did not say secret. Go back and look.

Funny the official report did,

Sure it did. As you refuse to answer the question I am free to
assume that you've never seen it. (Sauce for the goose. . .)

Incidentally there are lots
of fifties plants still running but few of them have any original
process equipment still running. Fewer still use original
controll equipment. (I should have phrased my original comment
better.)


You should have kept quiet,

I can't see why. So far I've not been corrected on anything
except for a major brain fart I long since admitted.


The causes of the
event were internal to the plant. The process affected was
obsolete and hazardous at the time and recognized as such.


A bulldozer tearing open a line would have
had the same effect.

How do you get the bulldozer to the line?

How you ever actually seen a pipe trench ?

We use bridges over here. The reason is frost, or so I was told,
but they use bridges in the southern states too.


Bull****, trenches and bridges are used everywhere. Bridges
are used to cross stuuf like roads, thats why they call em bridges

Have you seen a North American plant?


I think I'd better explain a bit. To aproach Maitland Works, or
Polysar, you've pretty much got to go in at a gate because the
ditches at the road are substantial. The gate is no real barrier
(and I've used a loose definition of "at" because the fencing
between the parking lot and the plant is ordinary chain link.)
Most plants are similar.


So no real barrier at all in fact

Certainly, read on.


The plants are pretty spread out. At Miatland, it's about a
fifteen minute walk from the gate to the Cyane tower, and farther
to the other nasty processes and the tank farm. Ten minutes would
suffice (in 1975) to render the tower (really the associated
piping) safe, so even if the event started in the parking lot,
they should be able to handle the situation. Polysar is more
spread out and easier to shut down.


A LOT can happen in 10 seconds let alone 10 minutes

Yes but there's clearly time to deal with this sort of incursion
which is the point. An air-strike is clearly not called for.


Then how do you get the
line to dump much more than its contents?

Have you ever calculated how much Cyclohexane
a 14" line 1000 m long contains ?

Try it , just for kicks.

Try to find an continuous kilometer long pipe in a modern,
North-American plant. Besides, without the pressure, you don't
get the explosion.


Jeesus Petey you've just been telling us how big the plants
you worked on were, get a grip will ya.

They just don't run lines (at least of hazardous stuff) that far
inside a plant without valving these days. There was a lot of
retrofitting in the eighties, I doubt many plants still need it.

And who still oxidizes
cyane outside a collum?


It was cyclohexane and its widely used in the production
of Nylon, and any leak is highly likely to oxidise externally.

Maitland Words is nylon intermediates plant. Cyane and
cyclohexane are synonyms here (is it different in Europe?).
Cyclohexane is slighjtly less nasty than high test gasoline.


Which is like saying arsenic isnt as bad as cyanide.

So you admit cyane and cyclohexane are the same. Now tell us how
gasoline (or cyane) is likely to oxidize externally.

You shudda kept your trap shut.

The situation you describe is nothing like this. In your case
vapour burns as soon as it finds an oxidizer, mixing is not
possible. Shut-offs would function automatically and limit the
amount of fuel. There will be no big bang, although there would
be one hell of a whoosh.


You are assuming no coincident or consequential damage occurs, this
is a POOR assumption. What structures are being weakened
by that flame and what happens when they fail.

No an awfull lot. That's what the controlls are about.


Controls dont stop steel losing its structural strength
in a fire

No, they limit the duration and intensity of the fire.

Maybe, maybe not.

That's life. Would you call an air strike in a populated area on
the chance they won'r function?

BTW, I'm assuming the builldozer doesn't get far into the plant.
It's not all that easy to do here.


Bull**** Peter, all that protects most plant are earth bunds and
chain link wire fences

Not bull****, as I explained above.


Quote "The gate is no real barrier"

Quote "Certainly, read on." I made the point about no real
barrier myself and clearly. That's because barrier isn't the
issue, distance/time is.

It is such risks that are rarely analysed and often
provide the nasty shock when an incident occurs

One of the worst industrial Bleve's happened on a
french plant where a small fire started at a faulty valve.
Trouble is the flame impinged on a LPG storage sphere

BANG


You've still not dealt with the basic question. Which is whether
there was a chemical plant near the incident that was so grossly
mis-constructed and mis-managed as to be vulnerable to such an
attack.


I responded to a claim that it couldnt happen - IT CAN

I think you might have misread the claim or I might have mistyped
it.

The furnace scenario you chose shows little understanding of
explosions or chemical plants.

Really , care to dispute the facts ?

I did. You snipped it without comment.


I'll take that as a no

Given that what I said is an explicit "yes", I think you're
erring.

The plant you chose is ludicrously
different from existing types.


Peter I have worked in this industry since I was 16, I have
seen 2 major Petrochemical incidents and investigated many
others. One of those included a major fire and explosion
caused by a mobile crane striking a pipe bridge.

Go find your Granny and teach her to suck eggs.

You too. Care to try to tell me that F was like a modern plant?

It had cyclohexane lines, so do modern plants.

DOH

I've already dealt with that at some length.


Evasion doesnt count

Evasion ot what?

Peter Skelton