Video of the 1986 “Goldfish” Release Test of hydrofluoric acid (HF) shows the formation and spread of a ground-hugging toxic cloud. In the test carried out by Lawrence Livermore National Laboratory research scientist Dr. Ronald R. Koopman, 8,300 lbs. of HF were released within 2 minutes. 100% of the acid became airborne in a dense, ground-hugging cloud of deadly HF.
While the Torrance and Wilmington Valero refineries use Modified Hydrofluoric Acid (MHF) with 6-10% sulfolane to reduce volatility, the amount is too little to prevent a toxic cloud, a fact that has been confirmed by the AQMD.
Each of the two settler tanks at the Torrance Refinery holds 50,000 lbs. of HF — six times more than the 1986 “Goldfish” Release Test.
TRAA Science Advisory Panel member Dr. George Harpoles’ seminal article on the equivalent behavior of HF and MHF in a catastrophic accidental release concludes with the paragraph:
“Dangerous concentrations of HF could persist miles away from the refinery. The typical layers-of-protection approach (barriers, water sprays, pumps to spare vessels, etc.) may save lives for certain smaller leaks. However, a more catastrophic rupture, simultaneous with failure or bypass of the protection systems, is easy to imagine – in large earthquakes, accidental or deliberate explosions, or fire. Moreover, the delivery trucks traveling to the refinery carry MHF in similar quantities, and are even more vulnerable. They have no spare vessel or water-spray system. They are exposed to the public and subject to crashes. There is clear danger to the community in the use of MHF at refineries in urban settings.”
Some Thoughts on the South Coast AQMD Rule 1410 Refinery Committee Meeting by the TRAA Science Advisory Panel
Several members of the TRAA Science Advisory Panel attended the AQMD Refinery Committee Meeting in Wilmington CA on September 22, 2018. This was a particularly important meeting because two of the world’s leading experts on the dangers of hydrogen-fluoride use in refineries gave presentations: Dr. Ronald Koopman on the large-scale HF release experiments — The Goldfish Tests — he conducted in the Nevada desert in 1987, and John Cornwell of Quest Consultants, conductor of the only field-scale MHF release tests in Quest’s Oklahoma facility in 1993.
The high point of the meeting was when the SCAQMD Refinery Committee Chair, Dr. Clark Parker, asked each expert his “$64,000 Question” — Would 6-wt-% MHF act the same as pure HF?
Dr. Koopman expressed his profound skepticism that the additive would do much good — “I would guess that would be a very small effect.” (Watch:https://youtu.be/qwo08BtEQuM?t=7460)
John Cornwell emphasized the small amount of additive is unlikely to have much of an effect, and there’s no data to show that it does. He pointed out to Dr. Parker that physical chemists use mole percent (molecule count), and states, “If MHF is 6% by weight and 1% by mole, and you are going to modify the vapor pressure or modify the characteristics of the fluid, you’ve got to have some data to show that’s true” (Watch:https://youtu.be/qwo08BtEQuM?t=8874).
This publicly-stated testimony by the world’s two leading experts expressed a high degree of skepticism of the refineries’ safety assertions for MHF. They are in line with the TRAA Science Advisory Panel and the SCAQMD Staff. MHF and HF behave the same and both form ground-hugging toxic clouds.
On the heels of the 1986 “Goldfish” Release Test of hydrofluoric acid (HF), Mobil engineers sought some method to prevent the HF from forming a ground-hugging toxic cloud. In his illuminating presentation at the September 22, 2018 AQMD Refinery Committee Meeting (Watch:https://youtu.be/qwo08BtEQuM?t=5108), Goldfish Test Principal Investigator Dr. Ronald Koopman stated that the affect of the HF release “was much larger than we had expected and the downwind distance was further than we had expected” and “we found that the HF that was released all flashed into an aerosol and a vapor and so there was nothing that ended up on the collection pan or in that tank — nothing was captured — and that was a great surprise to us.”
In their attempt to do something to prevent the formation of a toxic cloud, in the early 1990s, Mobil engineers settled on the additive Sulfolane to suppress the vapor pressure and move HF fluid properties into the subcooled regime, where flash atomization will not occur. But, as seen in the graph above, at least 45% Sulfolane by weight (45 wt%) is needed to achieve subcooled HF at a typical settler-tank temperature of 105F. Although they did not know it at the time, this level of Sulfolane is far higher than the alkylation process can tolerate and still function. In refineries that use MHF, the Sulfolane level is as low as 6 wt%. That’s 1 mole% or one molecule of Sulfolane for every 100 molecules of HF. Continue reading “Superheated MHF Excluded from the Only Large-Scale Test Series”
Liquid flowing out of a pressurized tank will flash atomize if the liquid superheat (temperature difference above the boiling point) is large enough. Fthenakis claimed, “The critical superheat typically ranges from 5 to 15K [9 to 27°F] for many fluids of interest.”1 Flash atomization is the shattering of liquid jets into very small (often submicron) aerosol droplets due to the rapid vapor bubble growth of boiling. By contrast, subcooled (below the boiling point) liquid jets will still atomize when exiting an orifice, but then to droplets that are orders of magnitude larger, hundreds of microns in diameter.