Fuel flowing through the Pipeline

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The fuel flows at 5 MPH. Seems slow. Say 1500 miles from Houston to NJ. That's over 12 days for the first gallon to flow the length of the pipeline.

But unsure what happened when the pipeline shut down. Did the oil in the pipeline just stay where it was when pipeline was shutdown?
 
My guess is that it mostly stayed where it was. I doubt that the pipe is level, so I guess it's possible to have air pockets, but probably that it doesn't move unless pushed or gravity pulls it. And even with gravity pulling it downhill, there would need to be a way for air to get behind it for it to move at any decent speed.
 
I have a couple questions myself. I know they use pigs to separate the fuels when they switch product through the pipeline. How is the fuel pumped with the pigs coming through? And how far are the pumping stations spaced apart?
 
The way these pipelines work is that product is always in the line and is used to fill tanks at terminals. The volumes are controlled in the tanks. The line never empties nor has pockets of air. Spaced pumping stations replace the pressure losses. The spacing is engineered to match the terrain and elevation changes. I understand pigs are not used between fuels. The fuel is batched and the interface is collected and then re-refined. There is actually very little intermixing. That’s why these lines are computer controlled.
 
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The way these pipelines work is that product is always in the line and is used to fill tanks at terminals. The volumes are controlled in the tanks. The line never empties nor has pockets of air. Spaced pumping stations replace the pressure losses. The spacing is engineered to match the terrain and elevation changes. I understand pigs are not used between fuels. The fuel is batched and the interface is collected and then re-refined. There is actually very little intermixing. That’s why these lines are computer controlled.
Would you not need emergency shut down systems pinging data against models of a potential leak …
Even if HMI intervention was required … that’s still starting with remote executive action …
 
I was wondering about where all the refineries are. Wasn't quite aware that there aren't any refineries from Georgia to Maryland. I was thinking maybe some might only go a short distance, but there's basically nothing between certain points. I keep on hearing that Colonial has 5500 miles of pipes, but it's only about 1600 miles between Texas and New Jersey. Maybe some of it is pipes going in different directions, although I understand that some of their pipes are bidirectional.

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However, as an electrical engineer, I'm familiar with "pipelining" in electronics. The idea is that things can be split up into stages where each stage can be simultaneously operated with another piece of data in the previous stage. It's roughly akin to how a physical pipeline might transport 87 octane, 92 octane, and diesel one after the other. It's my understanding that the transmix of different gasoline grades isn't that bad because it can still be sold as the lower octane rating fuel. But mixing diesel with gasoline is another matter.

The one thing I'm not sure about is what happens if they have to do an emergency halt. They say the turbulent flow minimizes mixing. But what happens if there's no turbulent flow. Maybe with pigs they don't mix, but this pipeline stopped for several days.


How are different products and grades kept separate in the pipeline?​

Different product batches are pushed through the system next to each other. The stream is always in a “turbulent flow” condition which minimizes mixing. Products are sequenced in the pipeline according to their characteristics. For example, regular unleaded gasoline may be shipped next to a batch of premium unleaded gasoline. When the flow of product is “cut” or diverted for delivery or into a storage tanks, the “cut” is made to protect the entire premium gasoline batch, thus allowing some premium to be added to the regular, unleaded gasoline. Similar steps are taken to protect distillate products such as jet fuel, Ultra Low Sulfur Diesel (ULSD), and home heating oil. When products with incompatible characteristics come into contact with each other, the resulting interface is defined as transmix. Transmix is stored separately and re-processed into a useful product.​
cpc-product-sequence-infographic.jpg
 
Couple of thoughts. It may be 1600 miles from Texas to New Jersey - but the pipeline does not follow a straight line distance between them - there are a lot of turns - and they all add length. Also, recognize that the line is actually two pipelines that parallel each other, plus branches - pretty easy to add up to 5500 miles of pipeline when you put all that together.

Some of the diesel or distillate mixing concern is actually mitigated in the parallel portions of the system - typically one handles gasoline and the other handles diesel/jet fuel/ etc... If the gasoline has mixed more thoroughly, it may mean a shortage of high octane - but it can be sold as the lower octane it mixed with...
 
The two pipelines are 40 inches in OD and 36 inches in ID. Under static conditions there is very little energy to induce mixing; just the density differences in the fluids. Draw a scale diagram, 36 inches wide and hundreds of miles long. They don’t mix much, maybe a few hundred feet. The pipeline will begin filling tanks at terminals and airports along the way. I have no idea how they decide who gets fuel first, but I imagine they have some sort of protocol worked out.
Here’s a screen shot.

CD06B103-7CC2-400A-84FD-2585021B976F.jpg
 
Would you not need emergency shut down systems pinging data against models of a potential leak …
Even if HMI intervention was required … that’s still starting with remote executive action …
Yes B’y. We all know what happens when the driller touches the control screen with his clipboard and lets go the slips!
 
Based on some fluid dynamics I have heard of in the past, you do not want to use turbulent to "reduce mixing", it would definitely increase the amount of energy needed to pump the fluid between places. I was thinking if they have density / buoyancy sensor at the terminal they can easily detect what is in the payload and then turn on / off between different valve, and then flush out whatever in between with some extra before and after as intermix.

What happen if the intermix is diluted enough so you have a very very small amount of gas in diesel or the other way around? Still enough to meet spec?
 
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I have a couple questions myself. I know they use pigs to separate the fuels when they switch product through the pipeline. How is the fuel pumped with the pigs coming through? And how far are the pumping stations spaced apart?
Please Define "Pigs"
 
Searching for pipeline pig, it seems they are used for maintenance and not for separating fuels.


This article does mention pipeline pig to separate batches though, do maybe it's a genetic term - ?.

 
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Enbridge line 5 escaped the wrath of the Michigan governor for now and Enbridge is trying to get the necessary permits to bore a tunnel underneath the strait of Makinac to get the two pipelines off the floor of the strait and into the secure tunnel. This would be completely on Enbridge’s dime. It carries most of northern Michigan’s propane well as well as almost 1/2 a million bbls a day of crude oil to refineries supplying Ohio, Michigan, Pennsylvania, Ontario and Quebec.
 
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Searching for pipeline pig, it seems they are used for maintenance and not for separating fuels.


This article does mention pipeline pig to separate batches though, do maybe it's a genetic term - ?.

More common in non refined products lines … like a small offshore platform flowing commingled crude oil and water via the same line - to be processed at a much larger land based spread of specialized equipment and engineers etc …
 
I was wondering about where all the refineries are. Wasn't quite aware that there aren't any refineries from Georgia to Maryland. I was thinking maybe some might only go a short distance, but there's basically nothing between certain points. I keep on hearing that Colonial has 5500 miles of pipes, but it's only about 1600 miles between Texas and New Jersey. Maybe some of it is pipes going in different directions, although I understand that some of their pipes are bidirectional.

main.png


However, as an electrical engineer, I'm familiar with "pipelining" in electronics. The idea is that things can be split up into stages where each stage can be simultaneously operated with another piece of data in the previous stage. It's roughly akin to how a physical pipeline might transport 87 octane, 92 octane, and diesel one after the other. It's my understanding that the transmix of different gasoline grades isn't that bad because it can still be sold as the lower octane rating fuel. But mixing diesel with gasoline is another matter.

The one thing I'm not sure about is what happens if they have to do an emergency halt. They say the turbulent flow minimizes mixing. But what happens if there's no turbulent flow. Maybe with pigs they don't mix, but this pipeline stopped for several days.


How are different products and grades kept separate in the pipeline?​

Different product batches are pushed through the system next to each other. The stream is always in a “turbulent flow” condition which minimizes mixing. Products are sequenced in the pipeline according to their characteristics. For example, regular unleaded gasoline may be shipped next to a batch of premium unleaded gasoline. When the flow of product is “cut” or diverted for delivery or into a storage tanks, the “cut” is made to protect the entire premium gasoline batch, thus allowing some premium to be added to the regular, unleaded gasoline. Similar steps are taken to protect distillate products such as jet fuel, Ultra Low Sulfur Diesel (ULSD), and home heating oil. When products with incompatible characteristics come into contact with each other, the resulting interface is defined as transmix. Transmix is stored separately and re-processed into a useful product.​
cpc-product-sequence-infographic.jpg
Good posting. Since your map only shows the USA, you are missing the Irving Refinery in St. John, New Brunswick, Canada that supplies a lot of product to Boston and New York by ship.
 
More common in non refined products lines … like a small offshore platform flowing commingled crude oil and water via the same line - to be processed at a much larger land based spread of specialized equipment and engineers etc …
Friend of mine that retired from gas company said they travel thei the pipes clearing and little stuff that may be in out of the way.
 
Friend of mine that retired from gas company said they travel thei the pipes clearing and little stuff that may be in out of the way.
Then there are “ Smart Pigs” that are pumped down the line and electronically inspect the pipe for any wall thickness reduction, pitting, or any other anomalies that could cause a problem. The pigs are retrieved by a pig catcher which is a system of valves and a pressure chamber to retrieve the pig, close the valve to isolate it from the pipeline and de-pressure the chamber.
 
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