You may or may not be in the oil trade like I am, but you probably know enough to know that oil and water are not friends, right?
Well, not good friends. They know each other, for sure, though.
You'd be surprised at how your oil-based products are handled between when it leaves the ground and when it leaves the exhaust pipe of your car. I've told some of this before, and it's made people nonplussed, but here, because I'm bored and have to at some point turn some wrenches outside and am putting it off because damn, it's 1:30 am, are some fun facts about your oil.
1). Crude oil contains a shit load of water.
It's true. We loaded 25,000 barrels of crude the other day, and stopped to get a water cut, finding 4,000 bbls of water in the mix. I was shooting for 500 bbls in the mix, and sent the batch we had back ashore for decanting, where the crude will sit for a few days, then the water that settles out can be pumped out. We took more crude from another tank instead.
2). We wash our oil tanks with salt water.
This surprises people. When washing tanks prior to switching from carrying one grade of oil to another, seawater is boiled then run through pressure washers to scour the tanks clean. The runoff is pumped into a slop tank, and we'll get to that later. The tanks are then air dried using forced draft fans, and people will then go down in the tank with brooms to sweep up any dust and salt residue.
3) Slop water may or may not go back in the ocean.
Depending on where you are, the several thousand barrels of slop water (a mix of seawater and oil) will need to be disposed of. This is done by decanting- separating the oil and water. Since oil floats, this is not too hard- you pump out the tank from the bottom. On a ship travelling at a fixed speed, the water is pumped into the ocean past a series of sensors that measure the water content- some oil will go over the side, but less than a few liters per mile traveled, not enough to leave a sheen on the water. The sensors will close the valves automatically should the slop stream contain too much oil and also if the total amount of oil pumped exceeds a preset standard. In the meanwhile, however, oil IS going in the water at a few parts per million. Not nearly as much as your average outboard engine on a pleasure boat puts in the water, however.
For barges and vessels without tank washing systems, a pump-out company will vacuum out cargo residue and any slop water from cleaning operations. The slops are then reprocessed- boiled down to separate off the oil. This creates a smell like satan's outhouse. If you want to know what it's like, drive from New York through New Jersey on the Jersey turnpike. There are enough refineries there that the wind will push some of that to you from the refineries that encircle rt. 95.
I could go on, but I need to go do some dirty work. Caffeine kicked in, and even though it's in the middle of the night, I have to go play mechanic out on deck.