Runaway Diesel on the Deep Water Horizon - PeachParts Mercedes-Benz Forum

mechanicalman · #1 05-16-2010, 11:43 PM

Anyone else see the 60 Minutes piece on the Deep Water Horizon explosion? Apparently, the methane shooting up the well after the blowout preventer failed got sucked into the rig's diesel generators.

The generators produced so much excess voltage, the lightbulbs and computer monitors onboard all exploded before the generators finally blew up and ignited the methane cloud along with everything else coming out of the well.

http://www.cbsnews.com/stories/2010/05/16/60minutes/main6490197.shtml

pawoSD · #2 05-17-2010, 12:09 AM

That sounds really implausible....this is 2010, not 1905.....the generators would have automatic shut down systems on them for such circumstances, and the voltage regulators/over voltage protection systems on the system would have prevented any such voltage issues. Computer monitors do not explode, especially LCD's....

mechanicalman · #3 05-17-2010, 12:21 AM

These were all things Mike Williams, the chief electronics technician onboard, said in the interview. If the generator was producing excessive voltage I don't think that would trip the breakers.

And if the air coming into the intake was already fuel enriched, how would the generators stop themselves? Shutting down the fuel injection wouldn't help anything.

Lastly, he never said anything about the monitor being an LCD.

Besides, with what's coming out about the safety records of the parties involved, I wouldn't be surprised if all those safety measures had been missing or inadequate.

JohnM. · #4 05-17-2010, 12:23 AM

Pretty good story, might have happened that way. Incompetent worker and his incompetent boss look to be to blame for the entire thing, based on this article? On top of the already sketchy maintenance/safety. These two just broke the camels back so to speak.

I also didn't know that the execs? from BP were there to congratulate them for 7 years without a safety issue when all this hit the fan.

Quote:

Williams says, during a test, they closed the gasket. But while it was shut tight, a crewman on deck accidentally nudged a joystick, applying hundreds of thousands of pounds of force, and moving 15 feet of drill pipe through the closed blowout preventer. Later, a man monitoring drilling fluid rising to the top made a troubling find.

"He discovered chunks of rubber in the drilling fluid. He thought it was important enough to gather this double handful of chunks of rubber and bring them into the driller shack. I recall asking the supervisor if this was out of the ordinary. And he says, 'Oh, it's no big deal.' And I thought, 'How can it be not a big deal? There's chunks of our seal is now missing,'" Williams told Pelley.

moosejaw · #5 05-17-2010, 01:26 AM

Most generators have under/over voltage and frequency trips. Your prime movers have under/over speed trips also. Something doesn't add up here.

TylerH860 · #6 05-17-2010, 01:37 AM

Yup, the story is way too dramatic.

mechanicalman · #7 05-17-2010, 01:59 AM

I know generators have voltage trips, but if the generators suckin' a massive cloud of methane and pumping crazy voltage, couldn't the voltage trip get fused closed or could the voltage exceed the ability of the trips to interrupt the circuit?

Safety equipment fails all the time, and I'd be surprised if engineers envisioned something like a massive methane vent causing the generator to run away.

cmac2012 · #8 05-17-2010, 03:49 AM

One of the main laws of physics: that which can go wrong, will go wrong. Especially when the action is taking place a mile underwater.

One wonders what sort of disaster would have to occur, or how many back to back, before the hunger to drill baby, drill abates in our land.

moosejaw · #9 05-17-2010, 06:24 AM

Quote:

Originally Posted by mechanicalman

I know generators have voltage trips, but if the generators suckin' a massive cloud of methane and pumping crazy voltage, couldn't the voltage trip get fused closed or could the voltage exceed the ability of the trips to interrupt the circuit?

Safety equipment fails all the time, and I'd be surprised if engineers envisioned something like a massive methane vent causing the generator to run away.

They are two seperate things, the generator and the prime mover (the diesel engine). The generator output breaker will have various trip points set on it. Even if the motor kept going and went into overspeed, then the output breaker would have went on high frequency.

These things are typically set pretty tight. For 60hz you would have ~ 65 high and 55 low trip points for high kw/high dollar gen sets. 460/480V regulators usually have failover to ~500v if the regulator fails.

This all assumes that the equipment was not tampered with.

Things just don't add up.

R Leo · #10 05-17-2010, 09:21 AM

A runaway diesel was also the cause of BPs Texas City explosion. In that situation, I believe a truck engine near the worksite started ingesting combustible vapors, ran away and when the engine self destructed, the sparks started the conflagration.

R Leo · #11 05-17-2010, 09:29 AM

I stand corrected. The BP Texas City explosion was caused by someone starting a truck engine in the presence of flammable vapors.

layback40 · #12 05-17-2010, 09:38 AM

A diesel will not run on straight methane mixed in the inlet air. I know of diesel CNG buses & trucks, they will not run if the diesel is shut off. Methane will not compression ignite in a diesel motor.
In time I am sure the real reason for the fire & leak will come out. At the moment there are too many running around with all sorts of theories.

PaulC · #13 05-17-2010, 10:38 AM

Quote:

Originally Posted by mechanicalman

Anyone else see the 60 Minutes piece on the Deep Water Horizon explosion? Apparently, the methane shooting up the well after the blowout preventer failed got sucked into the rig's diesel generators.

The generators produced so much excess voltage, the lightbulbs and computer monitors onboard all exploded before the generators finally blew up and ignited the methane cloud along with everything else coming out of the well.

http://www.cbsnews.com/stories/2010/05/16/60minutes/main6490197.shtml

Future design note: Surge protectors are available at Radio Shack.

Mike D · #14 05-17-2010, 10:46 AM

Quote:

Originally Posted by PaulC

Future design note: Surge protectors are available at Radio Shack.

Ya can get them cheaper at Walmart!

Cuts down on the overhead and boosts the profit margin.

Emmerich · #15 05-17-2010, 04:37 PM

Lets put on our thinking caps folks. What do you think would happen if methane got into a motor with a 20:1 compression? Hint: no runaway anything.

On this rig, the methane ignited AT the engines (not the generators, the draw-works (they power the traveling block of the rig to raise and lower the drill pipe) The engines were blown off the rig.

The gas also got into the mud pumps, boom, those left the rig as well, took 2 mud engineers with them. 9 were toasted in the first explosion.