Vinyl Chloride “Controlled Burn” East Palestine Derailment Surprising News

[Euclid]

Perry Babin

On pages 143-146 multiple methods of venting were listed. Which one was used?

 

The method chosen for five cars of vinyl chloride in this wreck is called “Vent-and-burn.”  It is also called the “Last resort” for reasons that were put forth in the publication.  The main reason seems to have been that they were unable to determine what was actually occurring in the tank car loads of vinyl chloride, and thus it was too dangerous to conduct work right next to them.  The two conditions that were not entirely resolvable were temperature of the vinyl chloride and whether it was undergoing a potentially catastrophic chain reaction called polymerization.  That could cause an explosion if polymerization was occurring or was on course to occur. 

 

If they knew the temperature was stable and low enough to prevent polymerization, and also knew that no polymerization was under way, they could have chosen to transfer the vinyl chloride from the damaged tank cars to tank trucks and then hauled it to a safe processing facility.

 

But that approach was deemed unacceptable because in not knowing the load condition, there was no way to know if it was safe enough to get workers right up to the tank cars and perform the necessary “Hot tap” option for setting up a piped transfer of the vinyl chloride from the tank cars to trucks. 

 

So they ruled out the transfer recovery option, and chose the option called vent-and-burn.  For a time, it was also referred to as a “Controlled burn.”  However, I have read that the EPA said it was not a controlled burn, and they instead referred to it as an “Open burn.”  A “Controlled burn” refers to setting a “back fire” to confront and stop a forest fire that is advancing toward the back fire.  As such, a controlled burn is constructive tool.  The purpose of the open burn is to extract the vinyl chloride from the tank cars, flow it into an open ditch, and incinerate it.

 

Whatever you call it, the burn was set up by digging a trench passing by the derailed tank cars.  Then small explosive charges were placed on each car at the highest and the lowest elevations.  Then ignition flares were set up along the trench.  Then the charges were fired and their explosions punched holes through the tank car walls.  The lower hole in each car allows the vinyl chloride to flow into the open ditch, and the hole at the higher location on each tank car allows air flow in to replace the draining vinyl chloride.  The ignition flares ignite the ditch full of vinyl chloride which burns with great vigor.  During this process, it is imperative that no vinyl chloride whatsoever be inhaled by any people.

[Perry Babin]

On pages 143-146 multiple methods of venting were listed. Which one was used?

[BaltACD]

Euclid

[Euclid]

Here is excellent detailed information in a publication by Union Pacific called, Handling Damaged Tank Cars. 

 

The East Palestine derailment involved issues surrounding the practices of “Hot Tapping,” and “Vent and Burn.”  Both of these procedures are well described in this publication, including the inherent risks. 

 

 

http://www.chagrinsehazmat.com/PDF%20Documents/RestrictedFiles/PDF%20Files/Handling_Damaged_Tank_Cars.pdf

 

 

Contents:

Overview .............................................................123

Tank Car Problems ...............................................124

Section 1: Methods for Plugging and

Patching Damaged Tank Cars

Overview .............................................................125

Reference ............................................................125

Plugging and Patching Materials ..........................126

Section 2: Methods for Removing Product Section 2:

Methods for Removing Product

Overview .............................................................129

References ..........................................................129

Transfers .............................................................130

Gas Transfer Using a Vapor Compressor ..............132

Gas Transfer Using a Vapor Compressor

and a Liquid Pump ...........................................133

Gas Transfer Using a

Compressed Gas (Inert Gas).............................134

Gas Transfer Using a Liquid Pump .......................135

Gas Transfer Using Product Vapor

Pressure with or without Flaring .......................136

Liquid Transfer Using a Liquid Pump ....................137

Liquid Transfer Using a Compressed Gas .............138

Flaring .................................................................139

Flaring Vapors......................................................141

Flaring Liquids .....................................................142

Venting ................................................................143

Vent and Burn ......................................................145

Hot and Cold Tapping ...........................................147

 

I tend to conclude that in cases of so-called, “high speed derailments” with flammable or explosive hazmat in tank cars, the method of dealing with the wreck is going to be vent-and-burn.   I conclude that because the damage to the tanks and valves is likely to be great enough to make methods such as transfer, or hot tapping too dangerous for the workers involved.  So that leads directly to the “last resort.”

 

When I listen to the reasoning of the people on the ground at the East Palestine derailment, they seem to come to my abovementioned conclusion.  They say they investigated all options and the last one was the only one acceptable, so they did the vent-and-burn option. All others that might successfully address the problem were deemed too risky for the men on the ground to execute.

 

In a high speed derailment, tank cars are likely to jackknife and crush together under the force of the trailing cars that are still on the rails. 

 

As my opinion, I note two factors that pushed the decision away from hot-tapping, toward vent-and-burn as follows:

 

1   Inability to determine tank car temperature, on a “whole tank” basis.

 

2   Inability to determine presence of tank car contents polymerization.

 

As I understood the testimony at the NTSB interviews of people on the ground, both of the above shortcomings were described.  In any case, they bypassed the hot-tap option and selected the option of vent-and-burn.

 

It seems to me that there is a need for tank cars that can monitor and display internal temperature and temperature trends that would be based on sensing at several locations inside of the tank.

 

There is also a need for tank cars that can monitor the contents of vinyl chloride and determine the probability of, or the actual existence of polymerization. 

 

These conditions of the load should be sent wireless to a safe distance from the wreck.  

 

[BaltACD]

I recall the name Red Adair, but not from Boys Life, and I have also watched the John Wayne movie 'Hellfighters'.  That being said oil field fires are a relatively KNOWN opponent as opposed to HAZMAT incidents that today's first responders must handle.  HAZMAT and their incidents are all unique, depending on the specific properties of the particular chemical that is involved and the conditions that are surrounding the affected chemical containers.

If 'Hellfighters' is any indication - there was a lot of 'cowboy' thinking being deployed.  I would like to think Mr. Adair was less of a cowboy in his real operations.

[MidlandMike]

Overmod

My problem is that I was raised with Boy's Life-style stories about the heroic exploits of Red Adair.  That sort of outfit would have figured out some way to hot-tap the cars "enough" to avoid the need for the breach... right???  

...

I saw the John Wayne movie loosely based on Red Adair's oil well fire fighting career, and one line I remember is him saying sometimes you have to "walk away" from an impossible job.  (That usually involves drilling relief wells to try to intercept the high pressure zone.)

In my oil field career, I have been on blowouts and oil well fires, and any heroics I saw happened when the drilling crew was trying to control a blowout or evacuate any citizens in the area.  When the well fire control specialists get there, everything done is purposeful and well thought out.  The scene is methodically cleared of all debris, to eliminate additional ignition sources, before they get to working on the well itself.  While fire generally consumes oil, gas and hydrogen sulfide, sometimes carbon dioxide also comes up the wells, but I've never seen that put out a well fire.

As far as hot tapping, I have only seen that done in gas storage fields on old (poorly) plugged and capped wells, and that was in the spring/end of heating season when field pressures were at the lowest.

[tree68]

Euclid

It will show up as the present, and then we will learn the result. 

Hence the five step process....

[Euclid]

If there were no downside to the open burn-off I would conclude that it was the best option.   But we won’t know until enough time passes to conclude that the burn-off did not expose residents to vinyl chloride.  And I conclude that will take about 10 years. 

 

Here is safety information about working with vinyl chloride:

https://nj.gov/health/eoh/rtkweb/documents/fs/2001.pdf

 

I believe the best option would have been to evacuate all the people out of the fallout zone during the burn-off.  Also included would be thorough, competent, and properly equipped testing in the fallout area to make sure that property beneath the fallout zone was not being contaminated with vinyl chloride. 

 

People love to say hindsight is always 20/20 meaning you can’t know the future.  But there is no need to know the future ahead of time.  It will show up as the present, and then we will learn the result. 

[tree68]

BaltACD

ALL those involved in a incident, Railroad, Contractors, First Responders, State Agencies, Federal Agencies are endeavoring to make the best possible decisions based upon the information and data that they come into possession of.

This can't be emphasized enough.  Nobody is looking at a situation and thinking "how can I make this the most painful for all involved."

That said, hind sight is almost always 20-20.  But in the heat of the moment, you do the best you know how.  Sometimes it turns out that you had wrong information, interpreted it incorrectly, or things just didn't turn out the way you thought they would.  Life's like that, too.

[Euclid]

Perry Babin

 

 

Euclid

Then a decision was somehow made to burn all five tank cars of vinyl chloride rather than just the one that had been suspected of developing polymerization. So the plan was executed with a massive open burn to dispose of the vinyl chloride.  

 

 

 

 

In a situation like this where someone outside of the railroad makes a decision that results in large scale damage/pollution (where there would have been none), is the RR likely to have to pay for the damage/pollution cleanup, lawsuits... (again, where there would have been none if the tanks would have simply been left alone)?

 

We don’t know whether the decision was made by one or more people outside of the railroad or inside of it.  From what I gather, I assume it was both.  If they had not done the burn-off, how would they have proceeded to get the track back into operation?  What would have been their procedure? 

 

I would not be surprised if loaded tank cars of hazmat in a pileup almost always rely on a burn-off to clear the line.   Many of them probably just burn in fires caused by the derailment.  

[BaltACD]

Perry Babin

In a situation like this where someone outside of the railroad makes a decision that results in large scale damage/pollution (where there would have been none), is the RR likely to have to pay for the damage/pollution cleanup, lawsuits... (again, where there would have been none if the tanks would have simply been left alone)?

The railroads, as carriers, are ALWAYS on the hook for ALL the costs resulting from a HAZMAT incident - even when they 'didn't do' anything with the shipment that became a HAZMAT incident on their property.

In addition to all the clean up and remediation costs they also have to make the shipper 'whole' for the loss of the contents of the cars.

ALL those involved in a incident, Railroad, Contractors, First Responders, State Agencies, Federal Agencies are endeavoring to make the best possible decisions based upon the information and data that they come into possession of.

[Overmod]

I believe Norfolk Southern accepted full responsibility for the cleanup and all sorts of community costs beyond it, within hours after the accident.  Even that was not quick enough for some, who needed to get in quick with the insults, threats, and consequences for what the railroad already had said it was going to be doing.

No matter whether 'incident command' turns out to have made the awful choice or not, Norfolk Southern will pay for the wreck cleanup, and the full cost of decontaminating the ROW and adjacent areas of spill, and in all probability the EPA's costs for taking over incident management to the chemical equivalent of 'cold shutdown'.

But let me stop you right away, very hard, when I see you write something like 

Perry Babin

(again, where there would have been none if the tanks would have simply been left alone)

First, we have no idea that one, or more, of the subject tanks would not have breached or detonated if the tanks had been 'simply left alone' in the state reported.  It is nice 20:15 hindsight to say "all would have been well, so you're going to pay extra for rank unsafe behavior... or for expedience in getting the line open to traffic ASAP by removing the BLEVE hazard... or for watchful waiting to go in and hot-tap the cars in order of perceived danger."  But we do not know that some, or indeed all, the cars might not have gone off uncontrolled, perhaps with far worse consequences that even the screwed-up burn.

[zugmann]

Perry Babin

is the RR likely to have to pay for the damage/pollution cleanup, lawsuits... (again, where there would have been none if the tanks would have simply been left alone)?

This will be kicking around the court system for years.  Hence a lot of the finger pointing and rear end covering by the players. 

[Perry Babin]

Euclid

Then a decision was somehow made to burn all five tank cars of vinyl chloride rather than just the one that had been suspected of developing polymerization. So the plan was executed with a massive open burn to dispose of the vinyl chloride.  

 

In a situation like this where someone outside of the railroad makes a decision that results in large scale damage/pollution (where there would have been none), is the RR likely to have to pay for the damage/pollution cleanup, lawsuits... (again, where there would have been none if the tanks would have simply been left alone)?

[Euclid]

Although The Five Steps of Strategic Planning were required, they are so general that it is hard to know how they applied in this case.  However, we do have this massive NTSB interview of the many people who were involved with the course of action taken in order to address the five loads of vinyl chloride.  So we know what happened, 5-step plan notwithstanding.

 

What happened was the emergence of advice that one tank car was experiencing a sudden temperature rise that indicated a possible/probable/likelihood that a chemical reaction of polymerization was developing.  It was assumed that this would lead to an explosion that would send burning vinyl chloride and tank car shrapnel over a wide area of the town.  This theory suddenly required the only possible option of explosive breaching of the tank car, and flowing the vinyl chloride into an open ditch with igniters set up along it.  This was said to be the “least bad option.” 

 

From somewhere, an order was given to the group to make a decision within 15 minutes as to whether to execute this “least bad option.”  I do not know where that order to make a decision came from.  I also do not know if the party/entity that issued the order considers itself to have been a party to the approval of the plan. 

 

While this was developing, the manufacturer of the vinyl chloride, OxyVinyls, informed the decision-making group that there was no temperature rise trend underway, only a slight temperature rise and fall over time.  OxyVinyls also told the group that the vinyl chloride was chemically stabilized, and therefore incapable of exploding even if there had been a solid trend of temperature rise.  But their advice was ignored.

 

Then a decision was somehow made to burn all five tank cars of vinyl chloride rather than just the one that had been suspected of developing polymerization. So the plan was executed with a massive open burn to dispose of the vinyl chloride.  

[zugmann]

"Mark Trail" is still around?  Wow. 

 

 

[Steven Otte]

On a related tack... The newspaper comic strip "Mark Trail," which has an environmentalist slant, has for the past few weeks been focusing on a fictional train disaster very similar to the East Palestine wreck. 

https://comicskingdom.com/mark-trail/2023-06-26

(Today's strip, embedded below, is a pretty pointed critique of the railroads' press conference performance.) 

[BaltACD]

tree68

 

BaltACD

You mean the crisis level meetings among the parties didn't have a Secretary to take minutes of the meeting and potentially even a video recording of it? 

Meetings like that are usually held under a canopy, or maybe in the meeting room of the fire station...

That I am well aware of - 'the lawyers, however'.

Of course, with today's cell phones - personal and company issued ???????

[Euclid]

.

[tree68]

BaltACD

You mean the crisis level meetings among the parties didn't have a Secretary to take minutes of the meeting and potentially even a video recording of it?

Meetings like that are usually held under a canopy, or maybe in the meeting room of the fire station...

[BaltACD]

tree68

I would imagine that the five steps of strategic planning got a workout:

• Determine your strategic position.
• Prioritize your objectives.
• Develop a strategic plan.
• Execute and manage your plan.
• Review and revise the plan.
• It's possible that step four never got off the table sometimes.

You mean the crisis level meetings among the parties didn't have a Secretary to take minutes of the meeting and potentially even a video recording of it?

[tree68]

I would imagine that the five steps of strategic planning got a workout:

• Determine your strategic position.
• Prioritize your objectives.
• Develop a strategic plan.
• Execute and manage your plan.
• Review and revise the plan.
• It's possible that step four never got off the table sometimes.

[Overmod]

MidlandMike

You seemed to have changed your thoughts on the general advisability of hot tapping in this situation since your July 14 post.

Not really.  It was the 'consultants' who became scared by the D-53 release, and decided that hot-tapping had become impossibly unsafe for their employees.   With the expressed concern that the PRDs might be clogging with polymerized material, the only other ways to relieve pressure were to breach the cars selectively to blow the release in a way that minimized airborne jetting, breach them upward with controlled ignition, or do what you could to orient the rupture discs to let go 'away from anything important'.  None of these were good for incident response, or for East Palestine.  I would consider it likely that any open release would proceed to carbureted ignition in fairly short order, possibly accelerated by radiant uptake as the cloud initially turned 'black' at the droplet surfaces.

My problem is that I was raised with Boy's Life-style stories about the heroic exploits of Red Adair.  That sort of outfit would have figured out some way to hot-tap the cars "enough" to avoid the need for the breach... right???  

Meanwhile, we try not to judge the people on site, working with the information they had, and SOMEHOW deciding on an awful approach which left NS looking like an expedient, public-be-damned, incompetent outfit.  I am beginning to see how this was a comedy of communication errors once the consultants got scared off attempts to set up for hot-tap.  For example we see Wood go into a meeting, say to incident command that the consultants say it's unsafe to hot-tap and it looks from the temperature spikes that we'll have to breach before the safety consequences get much, much worse... and then have to leave that meeting to go talk to the NTSB people.  While incident command gets a sort of target fixation on the expressed 'necessity' of a breach as expressed... now not one, but all five...

[MidlandMike]

Overmod

...

The correct way, really the only correct way to have handled this was to contain the vinyl chloride.  That is what the 'hot-tapping' would have accomplished: reducing the internal pressure by pumping out and recovering a substantial amount of the vinyl chloride (any polymerization decreasing as the pressure was relieved) until the cars could be more safely approached and the remaining material extracted or passivated.

You seemed to have changed your thoughts on the general advisability of hot tapping in this situation since your July 14 post.

[Overmod]

Euclid

I assume that a 100% destruction of the vinyl chloride would have required the use of a sophisticated technical incinerator designed and built for the purpose.

I'll answer this last part first.  Yes, and this is the process I referred to as 'pyrolysis'.  One of those father's-nutball-broker get-rich schemes involved a mobile (dedicated and swap-boidy truck-mounted) complete handling system that was going to be used for sanitizing all the nasty oily soil excavated from the thousands and thousands of cut-rate automobile wrecking yards that became such rich sources of scrap for the Chinese in the 1990s.  Instead of excavating thousands of cubic yards and then having to isolate it and ship it in weather to and from some central processing site, the equipment would go to the job, the soil would be dug and shoveled through the process line, and then just replaced as appropriate.  (Yes, it was a good idea, just not something you wanted to assume all the risks of long-term...)

I think the operating assumption -- we're unlikely to have truly candid testimony on this, if so, for obvious reasons -- is that the vinyl chloride was being treated like a comparably low-boiling volatile hydrocarbon subject to BLEVE conditions.  The internal boiling action would break up the ejected mass of material, the heat would rapidly expand it, the air would thoroughly carburete the resulting vapor and finely-divided liquid, and the propagating combustion heat would finish the job of volatilizing and surface-burning any remaining droplets in the cloud.

What actually happened, I think, is that the cloud 'quenched' early, and ejected a considerable amount of fairly large droplets that 'went out' too early, or were only surface-burning as they fell back down to ground.  This is a different mechanism than what I think you're imagining, a huge 'fallout plume' drifting downwind with vinyl chloride, well, falling out of it as it cooled and condensed.  (It remains to be seen what the actual fallout pattern with time after the breach is mapped to be.)

The correct way, really the only correct way to have handled this was to contain the vinyl chloride.  That is what the 'hot-tapping' would have accomplished: reducing the internal pressure by pumping out and recovering a substantial amount of the vinyl chloride (any polymerization decreasing as the pressure was relieved) until the cars could be more safely approached and the remaining material extracted or passivated.

[Euclid]

[quote user="Overmod"]

 

 

Euclid

Mr. McCarty wonders if this focused tight column of upward discharge’ appearing to include liquid, contains polymerizing vinyl chloride.  He seems very concerned about this, apparently because it might prove that polymerization was under way, thus confirming the persisting question about that point prior to the burn-off.

 

 

That the discharge is liquid monomer can be determined from the flow characteristics.  The clouds are likely vaporized monomer becoming visible, just like water vapor from ''steam', by entrainment of the edges of the released jet in the surrounding cold air.

 

Note that 'polymerization' inside the car would likely start at a number of sites -- that is sometimes called 'polynucleate initiation' because it starts at nuclei that have free-radical activity or otherwise induce enough polymerization to accelerate a local exotherm.  That implies that there may be a certain amount of polymerized (probably fairly short-chain) "PVC" in that jet, perhaps enough that it acts as a slush rather than a true liquid, and to me it would follow that such material might get into the PRD mechanism or ports and make it leak when 'closed' -- or, as with the car that was seeping until it suddenly and alarmingly stopped, that enough solid poiymer was aggregating at the valve and port connections to clog them up.

What I wonder is this:  Why there is no visible flame in this photo of the gaseous/liquid material rising after the burn-off has begun?

As with any BLEVE not directly accelerated by prompt critical-mixture ignition, the expanding vapor will not be ignited until (1) it has been carbureted, if it does not contain some internal oxygen or other reactive substance, and (2) an adequate initiation source, a sustained spark, hot-surface contact, or flame, actually initiates the combustion reactions.  One would not expect stabilized vinyl chloride to 'explode' on release, and of course any polymerization actively taking place under confined pressure and insulated temperature conditions would more or less promptly cease as the jet bled down the pressure and allowed more and more of the mass to contact very cold air, cooling further through expansion.

Since this was to be a 'controlled burn' -- whoever arranged the thing would have set up a defined method of ignition.  This ought to be, if it isn't already, something for the hearing to focus on intensely.  It may be that the presumption was to use some sort of spot pyrotechnics or flameholding device at the periphery, and 'rely' on entrainment carburetion and heat transfer in the blackening (and therefore thermally much more conductive, as at Flixborough) to accomplish the desired ignition of 'all or substantially all' the monomer.

I am neither a chemist nor a hazardous-materials specialist -- but it seems very clear to me from what I do know that reasonable atomization, then reasonable carburetion, and then assured full ignition in a cloud generated by ad hoc shaped-charge breaching -- and remember that the objection to hot-tapping the cars, something with minimal or no explosive involvement, was that even well before a 'critical' explosion situation, the cars weren't safe to approach for the necessary precise placement -- would be Not Very Damn Likely.  And that one of the most obvious things that would occur would be surface-burning condensed globules of expelled vinyl chloride (with or without a 'salting' of polymerized and less-reactive but still combustible material) that would condense into the virtual equivalent of rain and find a happy home both on the cold, cold ground and in any handy bodies of water.

 

 

This raises the question of whether vinyl chloride would have been lifted by the rising thermal plume without ever being ignited.

 

 

With a little (relatively rudimentary) analysis, you could figure out how the temperature would reduce on expansion into cold ambient, and how the driving pressure tending to lift the vinyl chloride against its own mass would decrease in time and space.  While those are BLEVE kinetics, they aren't yet complicated by ignition through the cloud and subsequent release and re-absorption of radiant heat.  To answer the direct question: it would have paddled condensing monomer over a substantial area, following the projection of streamlines I see pretty clearly in the first second or so of the drone video of the controlled release.  Now, the actual fallout plume might have been different in shape, or something else might have ignited the cloud or part of it randomly, and there'd probably be a hell of a lot more ground contamination requiring digging up and eventual pyrolysis.  I can't imagine anyone, anywhere, who was part of a trained and responsible incident command to order something like that to be done.  Perhaps someone like Tree might comment on what sort of triage assessment would have justified it. 

 

In other words, with this improvised flooded combustion system used here, [is it] certain that there will be complete combustion of the vinyl chloride “fuel”?

 

No.  Hell no.  In fact even a polite answer expressing how unlikely that would be would not fly on a family-friendly forum without a great deal of circumspection and self-control I no longer have concerning this aspect of the East Palestine accident.

 

 

Overmod, thanks for the explanation.

 

Okay, so as I understand; it is possible that, during the open burn, vinyl chloride could have been drawn up by the rising thermal plume without being ignited and destroyed by burning.  Then as the vinyl chloride continued to be carried upward by the lifting force of the thermal plume, the winds would tend to carry the chemical away laterally from the rising plume. 

 

This lateral drift would have stopped the lifting force acting on the vinyl chloride, so chemical would gradually fall back down to the ground and deposit on everything below including property and people.  Given the danger of exposure to vinyl chloride, how could this have been deemed an acceptable risk?

 

As I recall, there has been considerable news discussion stating that the burn-off of the vinyl chloride would convert it into other toxic byproducts such as phosgene, hydrochloric acid, and dioxin.   However, these concerns seem to have been largely dismissed for various reasons.  But I don’t recall ever hearing any news saying that the vinyl chloride itself could fail to incinerate and fall back down on people at various locations in Ohio and Pennsylvania.  This NTSB hearing circled all around this detail, but did not raise this issue of potential vinyl chloride fallout. 

 

I assume that a 100% destruction of the vinyl chloride would have required the use of a sophisticated technical incinerator designed and built for the purpose.

[Overmod]

Euclid

Mr. McCarty wonders if this focused tight column of upward discharge’ appearing to include liquid, contains polymerizing vinyl chloride.  He seems very concerned about this, apparently because it might prove that polymerization was under way, thus confirming the persisting question about that point prior to the burn-off.

That the discharge is liquid monomer can be determined from the flow characteristics.  The clouds are likely vaporized monomer becoming visible, just like water vapor from ''steam', by entrainment of the edges of the released jet in the surrounding cold air.

Note that 'polymerization' inside the car would likely start at a number of sites -- that is sometimes called 'polynucleate initiation' because it starts at nuclei that have free-radical activity or otherwise induce enough polymerization to accelerate a local exotherm.  That implies that there may be a certain amount of polymerized (probably fairly short-chain) "PVC" in that jet, perhaps enough that it acts as a slush rather than a true liquid, and to me it would follow that such material might get into the PRD mechanism or ports and make it leak when 'closed' -- or, as with the car that was seeping until it suddenly and alarmingly stopped, that enough solid poiymer was aggregating at the valve and port connections to clog them up.

What I wonder is this:  Why there is no visible flame in this photo of the gaseous/liquid material rising after the burn-off has begun?[quote]As with any BLEVE not directly accelerated by prompt critical-mixture ignition, the expanding vapor will not be ignited until (1) it has been carbureted, if it does not contain some internal oxygen or other reactive substance, and (2) an adequate initiation source, a sustained spark, hot-surface contact, or flame, actually initiates the combustion reactions.  One would not expect stabilized vinyl chloride to 'explode' on release, and of course any polymerization actively taking place under confined pressure and insulated temperature conditions would more or less promptly cease as the jet bled down the pressure and allowed more and more of the mass to contact very cold air, cooling further through expansion.

Since this was to be a 'controlled burn' -- whoever arranged the thing would have set up a defined method of ignition.  This ought to be, if it isn't already, something for the hearing to focus on intensely.  It may be that the presumption was to use some sort of spot pyrotechnics or flameholding device at the periphery, and 'rely' on entrainment carburetion and heat transfer in the blackening (and therefore thermally much more conductive, as at Flixborough) to accomplish the desired ignition of 'all or substantially all' the monomer.

I am neither a chemist nor a hazardous-materials specialist -- but it seems very clear to me from what I do know that reasonable atomization, then reasonable carburetion, and then assured full ignition in a cloud generated by ad hoc shaped-charge breaching -- and remember that the objection to hot-tapping the cars, something with minimal or no explosive involvement, was that even well before a 'critical' explosion situation, the cars weren't safe to approach for the necessary precise placement -- would be Not Very Damn Likely.  And that one of the most obvious things that would occur would be surface-burning condensed globules of expelled vinyl chloride (with or without a 'salting' of polymerized and less-reactive but still combustible material) that would condense into the virtual equivalent of rain and find a happy home both on the cold, cold ground and in any handy bodies of water.

This raises the question of whether vinyl chloride would have been lifted by the rising thermal plume without ever being ignited.

With a little (relatively rudimentary) analysis, you could figure out how the temperature would reduce on expansion into cold ambient, and how the driving pressure tending to lift the vinyl chloride against its own mass would decrease in time and space.  While those are BLEVE kinetics, they aren't yet complicated by ignition through the cloud and subsequent release and re-absorption of radiant heat.  To answer the direct question: it would have paddled condensing monomer over a substantial area, following the projection of streamlines I see pretty clearly in the first second or so of the drone video of the controlled release.  Now, the actual fallout plume might have been different in shape, or something else might have ignited the cloud or part of it randomly, and there'd probably be a hell of a lot more ground contamination requiring digging up and eventual pyrolysis.  I can't imagine anyone, anywhere, who was part of a trained and responsible incident command to order something like that to be done.  Perhaps someone like Tree might comment on what sort of triage assessment would have justified it. 

In other words, with this improvised flooded combustion system used here, [is it] certain that there will be complete combustion of the vinyl chloride “fuel”?

No.  Hell no.  In fact even a polite answer expressing how unlikely that would be would not fly on a family-friendly forum without a great deal of circumspection and self-control I no longer have concerning this aspect of the East Palestine accident.

[Euclid]

Overmod

 

 

Euclid

Look at the video starting at 7:15:55 where Mr. McCarty speaks.  He describes an unburned, white plume jetting upward from a tank car during the burn-off, which he speculates to be polymerization. 

 

 

I cannot get this to pull up due to AT&T bandwidth issues, but either you or Mr. McCarty have a major comprehension problem.

 

The 'unburned white plume' you saw rising in the drone video, which is presumably what Mr. McCarty is describing, is not 'polymerization', which would have slowed or stopped promptly upon the internal pressure being relieved by the breach.  Polymerization produces a solid, which does not 'jet' in a 'cloud'.  In any case the part of polymerization causing the alarm here is that it is exothermic -- it is the cause of the otherwise-unexplained heat excursions in the car(s).

The result of the breach is a typical boiling-liquid (the monomer being a liquid under pressure even at the heat extremes observed) expanding-vapor (the monomer expanded very rapidly from a great number of nucleation sites in the liquid simultaneously, like overcritical water in a rocket-type boiler explosion or opening a shaken soda can) explosion -- the expansion being further accelerated by the intentional rapid ignition of the expanding plume.  It was pretty clear from the drone video that the plume starts out white for what seems more than a second, and only as it begins to rise does it take fire.

That not all the monomer in the plume ignited is clearly recognized from the reports of decontaminating the streams.  It seemed evident to me that the blobs of monomer seen on the cold beds under cold water had fallen out of the plume at about that size, and sunk to the bottom on account of their greater density as they quickly reached thermal equilibrium.

In my opinion, had the car been breached after the general manner of the PRD release seen in D-53, so the evolving plume was better shaped and amenable to flameholding ignition, there might have been better experienced 'carburetion' of the monomer in air, and combustion and pyrolysis might have occurred more completely.  I think you'd still have the dioxin release question to address, though, among with all the other issues of a kludge response. 

 

I comprehend the words Mr. McCarty is saying, but not the overall meaning of his comments.  I also find it very difficult to formulate any questions or conclusion based on the format of the interviews.  It is so rambling and up close that it is hard to distinguish forest from the trees. 

 

In the time segment I referred to, Mr. McCarty is speaking in front of a still shot of two photos.  There is no drone shot or moving picture.  In one of the two photos, there is a vague detail that I believe Mr. McCarty is referring to as a jetting plume or focused discharge.  He concludes that he sees liquid in the discharge in addition to gas or vapor.  This discharge is jetting upward at about 75 degrees from horizontal.  It is situated in a mass of billowing white clouds appearing similar to steam clouds.

 

Mr. McCarty wonders if this focused tight column of upward discharge’ appearing to include liquid, contains polymerizing vinyl chloride.  He seems very concerned about this, apparently because it might prove that polymerization was under way, thus confirming the persisting question about that point prior to the burn-off. 

 

What I wonder is this:  Why there is no visible flame in this photo of the gaseous/liquid material rising after the burn-off has begun.   This raises the question of whether vinyl chloride would have been lifted by the rising thermal plume without ever being ignited. 

 

In other words, with this improvised flooded combustion system used here, it is certain that there will be complete combustion of the vinyl chloride “fuel” ?

[Overmod]

Euclid

Look at the video starting at 7:15:55 where Mr. McCarty speaks.  He describes an unburned, white plume jetting upward from a tank car during the burn-off, which he speculates to be polymerization. 

I cannot get this to pull up due to AT&T bandwidth issues, but either you or Mr. McCarty have a major comprehension problem.

The 'unburned white plume' you saw rising in the drone video, which is presumably what Mr. McCarty is describing, is not 'polymerization', which would have slowed or stopped promptly upon the internal pressure being relieved by the breach.  Polymerization produces a solid, which does not 'jet' in a 'cloud'.  In any case the part of polymerization causing the alarm here is that it is exothermic -- it is the cause of the otherwise-unexplained heat excursions in the car(s).

The result of the breach is a typical boiling-liquid (the monomer being a liquid under pressure even at the heat extremes observed) expanding-vapor (the monomer expanded very rapidly from a great number of nucleation sites in the liquid simultaneously, like overcritical water in a rocket-type boiler explosion or opening a shaken soda can) explosion -- the expansion being further accelerated by the intentional rapid ignition of the expanding plume.  It was pretty clear from the drone video that the plume starts out white for what seems more than a second, and only as it begins to rise does it take fire.

That not all the monomer in the plume ignited is clearly recognized from the reports of decontaminating the streams.  It seemed evident to me that the blobs of monomer seen on the cold beds under cold water had fallen out of the plume at about that size, and sunk to the bottom on account of their greater density as they quickly reached thermal equilibrium.

In my opinion, had the car been breached after the general manner of the PRD release seen in D-53, so the evolving plume was better shaped and amenable to flameholding ignition, there might have been better experienced 'carburetion' of the monomer in air, and combustion and pyrolysis might have occurred more completely.  I think you'd still have the dioxin release question to address, though, among with all the other issues of a kludge response.