 | ||
 | | |
 | ||
| | |
 | ||||||||||||||
|  |  | |  | |  | |  | |  | | |||
| | | | | | | | | | | | | | |
 | ||||||||
Dutch IGCC pioneers chalk up pain and gain Emergency response is behind schedule in the European public sector A new refining industry in Europe's Asian Corridor Commission proposes milestone energy proposal Replace fuel oil with distillate? Cancelled projects will sustain margins “Marine distillate not fuel oil from 2010” Branson's biofuels megastore You heard it here first: refinery CO2 storage a reality in Norway Buncefield 2: Investigation critical Where now for Swedish Class 1 diesel My slow awakening to climate change The luckiest motorist alive Safety row goes on over Europe's largest LNG terminal New WHO guidelines on city air quality put focus on diesel Would LNG really 'evaporate harmlessly' in an accident? Another lesson in the thermobaric bomb Spare a thought for the oil-rich But will the good times keep on rolling? Carbon storage and the zero emissions refinery Everything just changed E85 and high octane gasolines The problem of small-minded young engineers New Permit Regulations Biodiesel newbuilds and a new green superfuel Spilled wine and our split industry Drilling down into the prospects for IGCC The beginning of the start of the end of oil | Is safety in Europe 'beyond the normal worst case'? The independent group set up to investigate the terminal explosion and fire at Hemel Hempstead in Hertfordshire, UK, last December has uncovered fundamental problems with planning and emergency preparedness, as well as specific operational and safety issues with a system which allowed a massive overflow from a gasoline storage tank to continue unchecked for more than 40 minutes. In the 60 or so pages of its so-called Initial Report, the Buncefield Major Incident Investigation Board admits that from existing principles of flammability it can not explain why an ignition of gasoline vapour with no obvious source of confinement led to such a devastating explosion. The board has issued a further safety alert after investigating high level sensors, as well as serving an improvement notice on manufacturers. There may be a criminal prosecution. We don’t know yet. In any event, there are far-reaching implications from an incident which vastly exceeded the single gasoline tank failure which appears to have been the basis of planning, training and design for facilities like Hertfordshire Oil Storage Ltd. When I sat down to read the report I’d not long returned from a gasoline overfilling episode here on the island– a fairly work-a-day incident for our local fire brigade. A boat owner had pumped US $200-worth, about 37 gallons, of gasoline into the hull of his power boat, partially submerged the warm engine in fuel, and then found to his initial irritation that the engine stalled. A disconnected hose was the culprit. The day ended with only some wasted time for the holiday makers, while the gasoline, foam and water ended up tidily in three one hundred litre drums. Of course there’s quite a difference between the gasoline flow-rate from a retail pump – say, 10 gallons or 37 litres a minute – and from a gasoline pipeline into a tank farm. As I played around with the numbers to make them more thinkable I realised that the flow rate at Buncefield that day was comparable to 400 such tee-shirted holiday makers each with their own filler nozzle flowing freely onto the ground. Or think of 50 firemen spraying gasoline from their Fogfighters over the rim of an open tank. We know that from 7pm on the night of 10 December the tank in Bund A at Hertfordshire Oil Storage Ltd was receiving 550 cubic metres an hour. From 3am, 90 minutes after stock taking was completed with no abnormalities noted, the level gauge of tank 912 remained unchanged. But BP’s Coryton refinery was still sending winter grade gasoline. The tank would have been full at 5.20am but pumping continued until 6.01 with the flow rate gradually increasing to 890 cubic metres an hour. The ultimate high level switch that should have shut off supply to the tank did not operate. Because of this, a safety alert has been issued to terminal operators to immediately check change over reed switches made by Cynergy3 Components Ltd and its predecessors, along with guidance as to correct operation of a test lever/plate. The way in which the gasoline cascaded from a ventilation hole on the roof of the tank over the side and then hit a girder producing a second cascade contributed to the formation of a massive white misty vapour cloud of butanes, pentanes and hexanes. The investigators note that there was about 10% butane in the gasoline, putting it at the fizzy high end of European Winter Grade F gasolines. This will have contributed to the scale of the blast and, to make things worse, overtopping of the tank in the way mentioned led to a higher proportion of volatiles being emitted than would have occurred with a tank breach lower down. It was a still cold day and the vapour cloud was free to follow the topography off the site once the vapour cloud had reached a height of two metres and over-run the bund surrounding the tank. And here, it seems to me, is where the term coined by the investigators of ‘beyond the normal worst case’ begins to apply. Surprisingly, the planning approvals, safety distances and fire-fighting for terminals in the UK seems to have been premised on a particular worst case hazard – the radiative heat from a pool fire connected with a catastrophic collapse of the largest gasoline tank. Such a release of liquids was expected to overflow bunds, but otherwise be contained on site by tertiary containment measures like kerbs, drains and road bumps. Gasoline pool fires – the kind of fire burning by the time the TV cameras got near to Buncefield – are of course hot, dirty and nasty, but they’re tame compared to the destructive force of a vapour cloud explosion. And get this vapour cloud. By 6.01, investigators estimate that it had reached the walls of the neighbouring large office and factory sites, including Catherine House, which is almost 200m from the site, and spread to the neighbouring fuel storage facilities of British Pipelines Agency Ltd. The nature of the blast that followed at Buncefield so far defies explanation. The investigators put it like this: “Much uncertainty remains about why the explosion was so violent, generating overpressures of a magnitude much greater than current understanding of vapour cloud explosions would predict. For example, a method in current use would predict overpressures of 20-50 millibar (mbar) in the open areas of the Northgate and Fuji car parks. The current best estimates of the overpressures that actually occurred in these areas are of 700-1000 mbar, leading to extensive damage to adjacent buildings.” A 50 mbar blast pressure might be expected to damage a roof by blowing off tiles. 700-1000mbar is well into the range that would lead to complete destruction of all unreinforced buildings. | |||||||
Download Energy Industry Resumé with work samples Profile: Tim Lloyd Wright MA Here you'll find a brief profile of my work with international energy, transport and associated environmental issues. Energy trends articles You heard it here first: refinery CO2 storage a reality in Norway From the archive... Over-processed fuel leaves oil tankers adrift | ||||||||
| | | | | | | | |
