Case study of a hydrogen peroxide related deflagration in a wastewater treatment tank

Wehrum, William L.

doi:10.1002/prs.680120403

Cited by 12 publications

(3 citation statements)

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“…30 Previously it has been used in effluent treatment, soil bioremediation, industrial gas treatment and recovery of metals from Li-ion batteries. 30,31 Therefore, it is important to study the effect of H 2 O 2 addition on metal leaching from WEEE.…”

Section: Introductionmentioning

confidence: 99%

Leaching of metals from printed circuit board powder by an Aspergillus niger culture supernatant and hydrogen peroxide

Jadhav

Hocheng

2016

RSC Adv.

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Section: Introductionmentioning

confidence: 99%

Leaching of metals from printed circuit board powder by an Aspergillus niger culture supernatant and hydrogen peroxide

Jadhav

Hocheng

2016

RSC Adv.

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“…The water slug mechanism might have relevance for other “closed vessel” explosions involving gassy reactions and elevated oxygen concentrations. A case in point is Allied‐Signal's wastewater tank explosion discussed a quarter century ago at the 1993 Loss Prevention Symposium . The investigation included the scenario “corona discharge generated by cascading liquids” but this was considered unlikely.…”

Section: Water Slug Sparking Mechanismmentioning

confidence: 99%

Deflagration in empty tank being rinsed with water

Britton¹,

McDavid

2019

Process Safety Progress

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A deflagration occurred inside a 200-gal (0.757 m 3 ) atmospheric mixing vessel during the course of apparently normal operations. The vessel had previously been used to dilute 70% aqueous tert-butyl hydroperoxide (t-BHP) with deionized water. Ten minutes earlier the mixed batch had been transferred out and the vessel had been given a brief rinse with deionized water about 4 minutes after the transfer. The deflagration occurred soon after starting the second of two deionized water rinses. Although the hinged vessel lid was forced open and damaged there were no injuries or chemical exposures since no personnel were in the area at the time. The incident was caused by a faulty metering system that overcharged sodium hypochlorite (bleach) solution to the deionized water supply. The roughly 100-fold overcharge of bleach resulted in a vigorous, gassy reaction with t-BHP in the mixing vessel. The reaction generated a gas-phase mixture comprising mostly acetone plus about 90% oxygen. The ignition energy of a replicated mixture was 0.015 mJ, similar to that of optimum hydrogen-air, but with poor upward mixing of acetone the ignition energy could have been as small as 2 μJ. The source of ignition could not be identified with certainty; the "least improbable" scenario was considered to be a spark from an electrically charged slug of rinse water falling through an electrically charged mist that had formed during the gassy reaction. INCIDENTIn the batch process, 70% aqueous tert-butyl hydroperoxide (t-BHP) is diluted with deionized water in a stirred mixing vessel (mixer) then pumped to another vessel for reaction. Following liquid transfer, two separate additions of deionized water are made to rinse out the mixer. In each case the rinse water is sent to the reactor.On the day of the incident the dilute t-BHP mixture was made up as usual and pumped to the reactor. About 1 minute into the second rinse step a loud noise was heard by plant staff. Flammable gas detectors did not indicate flammable gas in any area. The control system was still operating normally with no alarms or signs of a process upset. Plant staff reviewed all the ongoing processes to help determine the source of the upset. The process was then put into hold. When the conditions in the plant were found to be safe, operators walked through the unit for a visual check of the process. The mixing vessel was found to have a damaged hinged lid, but no other signs of other damage, smoke, or soot. BLEACH METERING SYSTEMVarious processes at the plant share a common supply of deionized water that has been treated with dilute sodium hypochlorite (bleach) to limit biological growth. The bleach metering system is designed to dilute 12.5% bleach concentrate to 30 ppm in a deionized water supply tank. MIXING VESSELFigure 1 shows a sketch of the mixing vessel. The agitator is mounted near the side of the roof and the shaft angles down to the middle of the tank floor. The agitator shaft and deionized water nozzles are on opposite sides of the fixed half of the hinged lid. The o...

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“…There is a previously reported incident where decomposing hydrogen peroxide in a tank released oxygen, and the solvent vapour in the tank ignited. This was investigated by Pratt who concluded that the mechanism was that the bursting bubbles formed highly charged droplets and the corona discharges from the resultant electrostatic field ignited the vapour in the atmosphere in the tank.…”

Section: The Hazardmentioning

confidence: 99%

Safe Scale-Up of Oxidation by Hydrogen Peroxide in Flammable Solvents

Astbury

2002

Org. Process Res. Dev.

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Oxidation of species by hydrogen peroxide gives rise to the potential to release oxygen, which in the presence of flammable solvents can lead to an explosion risk due to the extreme sensitivity to ignition of the resulting oxygen-enriched atmosphere. The release of oxygen gas in the form of bubbles from the liquid can produce an electrostatic field, which is capable of igniting sensitive flammable atmospheres in larger-scale operations. A method of inerting the system can be applied which makes the atmosphere nonflammable and the reaction safe, whilst minimising solvent losses. A practical scale-up from laboratory flask to pilot scale of 150 kg demonstrated that solvent losses, whilst significant, are not a barrier to production of fine chemical intermediates on a commercial scale.

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Case study of a hydrogen peroxide related deflagration in a wastewater treatment tank

Cited by 12 publications

References 0 publications

Leaching of metals from printed circuit board powder by an Aspergillus niger culture supernatant and hydrogen peroxide

Leaching of metals from printed circuit board powder by an Aspergillus niger culture supernatant and hydrogen peroxide

Deflagration in empty tank being rinsed with water

Safe Scale-Up of Oxidation by Hydrogen Peroxide in Flammable Solvents

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