Wednesday, May 26, 2004

The Sweet Smell of Benzene

Anyone smell benzene on May 1, about 2 p.m.-ish?
About 414 lbs of the stuff leaked into the air over at Dow that day, along with about 16.9 lbs of ethylbenzene, 1.21 lbs of toulene and a pound of diethylbenzene.

Dow officials at first said they thought a lightning strike caused the "emission event," but upon further review (to coin the NFL phrase) it was attributed to "multiple relief devices ... relieving to the flare."

Like we were saying yesterday, that's the way things go here in Paradise. Valves fail, people make boo-boos, shit hits the fan. Not casting aspersions here. That's just our realist view of life on the Texas Petrochemical Coast. Like the old guy Mobster character portrayed by Lee Strasberg in Godfather 2 said, "This is the business we have chosen."

Or where we have chosen to live, as the case may be.

The world has decided it needs all the plastic stuff Dow (and others) make, and no one raises much hell when benzene or other stuff get leaked, and we're all gonna die someday anyway, so relax.

And we need gas, too, besides all the plastic. Same deal. Stuff happens. There are "emission events" at refineries like the Chevron Phillips complex in nearby Sweeny, where more benzene (33 lbs) escaped, along with a bunch of other stuff, on May 15. The "event" began at 5:25 pm and continued for 3 hours before the cause was discovered.

When it was discovered, quick action was taken. Yup, they closed a valve. Dang!

If you really REALLY want to know what happened, read the next italicized paragraph, but if you really don't want to immerse yourself in this information, just skip it. (Ed. note: It's italicized for your reading comfort, not because most of you have any remote interest in this stuff, but if you wade into it, you just may decide that you made the right decision not to pursue that engineering degree your daddy was pushing all those years ago) ...

Here goes, gulp:

"The Regenerative Thermal Oxidizer (RTO) tripped off-line at 17:25 and was restarted at 20:25 am. The RTO is the control device for the wastewater treatment system. When the RTO is off-line, vapors from the wastewater treatment system which contain VOC are vented to the atmosphere through the Aeration Tank 69. The RTO shutdown due to a high temperature alarm. It was discovered that a controller on a fuel gas valve had received a bad reading on oxygen content which caused the valve to fully open. This controller reads oxygen content in the vapors at the compressors which collect vapors from Wastewater Treater #1 and the loading racks and routes to the RTO. The controller compares the oxygen content to hydrocarbon content (ratio) in the vapor to ensure the vapors stay above the UEL (upper explosive limit). This valve allows fuel gas into the system to keep the ratio in a safe range. It appears to have received a bad reading for the Oxygen content. When this happens, as a safety feature, the fuel gas valve fails open to ensure enough fuel gas is in the line to keep the vapor above the UEL. The excess fuel gas in the feed to the RTO caused an elevated BTU content in the vapor feed to the RTO resulting in high exhaust temperature at the RTO. The RTO automatically shutdown as a safety precaution when the exhaust temperature exceeds 450 F. When the RTO shuts down, the valve on top of Tank 69 opens to the atmosphere. Once the problem was discovered, the valve on the fuel gas line was closed. The RTO was cooled down and restarted as soon as possible. "


But then, 3 days later, another emissions event strikes again at the same refinery, AND, at that SAME TANK 69! It happened at 5 a.m. and ended at 8:20 a.m.
Since some of you are about to nod off by now, only the annoted version of the report is presented herewith:

"...compressor...shut down...vented vapors...compressor was problems..."
Here's the toll of the second emissions event at pesky Tank 69:
1-Butene 3.0 lbs (est.)
Benzene 20.0 lbs (est.)
Butane 2.0 lbs (est.)
Ethylene 4.0 lbs (est.)
N-Hexane 1.0 lbs (est.)
Pentane 2.0 lbs (est.)
Pentene 1.0 lbs (est.)
Propane 5.0 lbs (est.)
Propylene 2.0 lbs (est.)

There are more of these emission events to report on, but not now and maybe not ever, as far as The Brazosport News is concerned. Let the Clute daily or the new paper in Angleton worry about it. Besides, nothing went kablooey in the aforementioned events. No one's dead. Or hurt. As far as we know. And benzene dissipates rather quickly, they say. SO HAVE A NICE DAY!


Anonymous said...

I love the smell of benzine in the morning. It smells like Angleton.

R. Duvall, Freer, Texas

Anonymous said...

yezza need to update this to