Hi MJC.
I'm sure the tecnical understanding of brittle fracture resides in the forums you've suggested, but I think it is important that knowledge of the phenomenon of brittle fracure be widely known.
Operational people need to know of it. It shouldn't be secreted away in a specialist arena...
Yes, with zero static head difference to induce flow, could thermally induced flow take over causing reverse flow through convection?
It doesn't really matter, 25362. The heat to the HE had been shutdown anyway. I just wanted to get the thermosyphon process clear in my head. You've all helped...
Hi Milton.
Yes, I believe I understand things correctly.
I'm examining the details of an accident that involved an absorber where the condensate level in its bottom was not under control. The investigation report is in the public domain. I don't represent any party.
The condensate level rose...
"JOM, is the HE a reboiler as the post heading suggests ?"
Great question. I've wondered about the definition of reboiler. My impression is it's a term liberally used for any HE at the base of a tower. This one has been called a reboiler.
In this case, the tower is an absorber. Condensate...
Thanks All.
That Wikipedia link was useful, Milton, thanks.
This has helped me. The case I was looking at involves liquid leaving the bottom of the tower to an exchanger and then re-entering the tower sump. So the flow is downwards. So thermosyphon (correct spelling, BTW) can't be involved as...
I've come across ther term "thermosyphon" in connection with reboilers on columns. I guess it implies flow of liquid induced by thermal gradient or something...
Can anyone give me a simple but correct explanation of "thermosyphon"?
John.
J.
I cannot give you the answer, but would like to point out a couple of matters revealed by actual accidents.
The US CSB last week presented its report into the Texas City accident. They said that persons in a flimsy building such as a trailer could be at greater risk compared to standing in the...
Maybe the fundamental question is why the personnel were located at this place. Was it essential or merely practical?
Perhaps we'll learn more when the CSB release their final report.
J.
epoisses,
I'm not advocating that doors be barred and entry prohibited during an emergency. Heck, no.
I'm thinking in terms of design and planning. Maybe the control room function and safe refuge should be separate design goals.
I've found an incident where 50 people came to the control room...
Lots of interesting comments on this topic. Thanks.
Can I reduce this "issue" to something simple?
What's the purpose of a control room? To control the plant.
Does that change in the case of an emergency? Course not.
So why use the control room as a mustering point? Why? Someone has said...
G,
Thanks for the lead on EERA. I see there are many publications about this. Good material. Mostly focussed on offshore. I'm more interested in land-based facilities. Offshore is a very special kind of workplace.
I'll have a look at Lees.
Do you think it would be useful to have reports on...
G,
"With modern instrumentation and CCTV systems there is no real need to have the control room located inside the plant. Locating it at some distance is an inherently safe approach"
In which case, it can no longer be a mustering point, can it? Where would field personnel muster in an...
Guidoo,
What about fumes or gases entering through the instrumentation dusctwork? I know cables should have glands and seals but there are cases where gases entered the room. Do people validate the integrity of these entry points a matter of routine?
(Incidentally, the Browns Ferry nuclear...
schnipp,
So, in your case, I think you're saying the personnel take refuge in the control room building but not in the actual control room. That would allow operators to continue with their control duties unimpeded.
With the case I mentioned, the plant fire burned instrumentation wiring and...
Useful comments, swn1.
In the case I know of, acidic fumes from a plant fire filled the control room, making it untenable. A poor refuge, especially for the injured personnel.
Another problem that you also aluded to, was the influx of numbers of personnel disrupting the operators' plant...
Sometimes control rooms are the designated mustering point for plant personnel in case of emergency. (I don't know how common this practise is.)
Has the wisdom of this practise been examined and written about? Does anyone have examples of a control room providing refuge during a real emergency...
Mike,
Most plate PHE applications operate with a flooded unit on both sides - process and heating medium. Level control inside the unit is not an issue.
Do you actually need a vapor space? If so, you're sort of operating it as a plate evaporator.
J.
J.
I wonder how the responsibilty is spread for ensuring a tank is not overfilled by a remote pumping station.
Assuming different companies operate the pump station and the recieving facility, would both companies have an obligation to ensure no overfill?
I wonder what the sales contract says...
JMW,
Yeah, I now understand what you mean by "constrained".
What's striking about Buncefield and Texas City is the simplicity of the accident processes. It would be some kind of comfort if they were the result of some complicated or exotic causes. But, they're really dumb events.
Buncefield...
