Please help with a gas pipeline problem we are having at my company. There is something stuck in a pipeline but the operators have no clue where. My question is, can I determine where the obstruction is in the system by recording the rise in pressure over time from a fixed measurement point upstream of the block? We can monitor static pressure, differential pressure, flow rate in mcf/d, temp and total volume sent past the sales meter. Ideally I would like to bring an equation to my masters to get a few crumbs from the table. Thanks.
Gas pipeline obstruction
>gas pipeline problem we are having at my company
>operators/technicians have no clue
>ask Veeky Forums for advice
you guys are running a real bang up operation
try ideal gas law PV=nRT
if you know P, n and T, you can find V, which basically gives you the length of tube you need.
If this doesn't work as a first approximation, you'll need to use van der waals equation I guess
same thing, find V.
Have you tried knocking on the side of the pipe until it sounds different somewhere?
Are you located in the US?
I was about to write this.
>knocking on thousands of kilometers of pipes
It should be very obvious bfrom a sudden change of pressure between compressor stations. You should not need to do any math, just read the instrumentation.
Once youve narrowed it down to between two points, use a pig you fucking savages.
>homework and work related problems
Thanks for the tips and keks. There are like thirteen pigs in the line because the part of Montana where the pipeline is located is know for inbreeding.
what does that mean?
There are 13 pigs in the pipe?
Yep. They just kept shipping them .
Device you push through a pipeline to determine damage/clear debris.
pls dont hurt the pigs or force them thru the pipe
thermal camera. there will be a notable cold spot in the pipe where the constriction is.
you must be referring to some fancy space age pigs, the ones I've seen are like foam cylinders they use to push liquids downstream. Also, these guys are cheap, I don't think they have pipe laser robots.
In the natural gas industry much more sophisticated models are used, with calipers and electrochemical sensors so as to pinpoint the exact spot where deformation occurs. This is a huge benefit ass you can dig a 10 foot trench to repair pipe instead of a 2000 foot one.
I have seen models produced by GE and Rosen, which can have 3 foot diameters and be in trains 15 feet long. These are usually owned by a pigging company & in a near-constant state of renting out to various contractors.
I forgot to mention the pipeline is buried. Otherwise you could almost see through the poly pipe to find the plug.
that looks wild. The pipe is like 6-8" diameter depending on the location.
Im genuinely curious, this isnt me trying to insult you or your company. How does your company stay afloat if they dont know how to take care of a routine problem like this? How long have they been around?
do you know how many start up oil and gas companies there are? any faggot with a well has his own "energy management firm".
>determine the speed of sound through the whatever is in the pipe
>send some kind of shockwave/ loud noise through the medium
>record how long it takes for the echo to come back
>divide by two and multiply by the speed of sound
That's how far away the blockage is.
brb, patent office.
p.s.: give me a job
find out where obstruction is by measured values - no chance.
but when obstruction triggers relevant p/V changes check up major repair locations of last years and these dilation bends after it.
do you not have an internship this summer user?
Nope. I guess I'll be doing research in computational structural optimization over the summer instead. It's super informal and unpaid, though. :/
you doing topology optimization? What sort?
you didn't apply to many places did you
Discrete combinatoric. I'm dividing the problem into a bunch of cells that can either be solid or void, then finding the optimal combination of cells. I came up with this pretty cool algorithm to do it too. It's a black box method that operates on sequences of bits, so I can apply it to all sorts of stuff.
My GPA is kind of bad because I'm more interested in working on personal projects that use more advanced material than what we learn in class.
>My GPA is kind of bad
first, thats not what i asked. second, nobody cares. they care about what you can do, not what your GPA is.
this optimism is worth a new meme.
>they care about what you can do
Well, apparently not. Hopefully they will after I publish some papers this summer, assuming everything goes according to plan.
Of course there will be noise, but that's nothing some audio analysis can't solve. Just run the data through this.
you are going to half to take into account the damping effect of flanges and bends. you'd have to accurately model the whole pipe to know what your signal should look like.
Gradual bends shouldn't be too much of a problem for a longitudinal wave, though elbows might. Maybe begin the analysis at a relatively straight run of pipe. There shouldn't be that many sharp corners in a long range pipeline.
point is, you are still going to have to pull out schematics and probably do some full scale analysis. it won't be as easy as going out, slapping a vibration sensor on it, and whacking it with a hammer.
in case company tries to solve prob one their own:
how big is change in pressure loss(we actually dont now in this thread).
estimate possible size of obstruction.
finding out if/which device fits to problem and if this event justifies invest.
waiting for device to arrive and of course pay for it.
built in device.
make tests, check reflected freq... ,... .
hoping measurement really helps figuring out where obstruction is. reality is a mad opponent.
in case company decides for solicitation:
doesnt matter which measurement method is used as long as firm solves problem(sound, PIG, mexican, magic).
thats why this is optimism. im sure OPs chief is looking for a solution now.
That's neat. Good luck beating conventional gradient based topology optimization. See "On the usefulness of non-gradient approaches in topology optimization," Ole Sigmund.
>>It's a black box method that operates on sequences of bits
if it's really blackbox, and not a genetic algorithm, try to see if you can beat genetic algorithms.
Sounds like it might be interesting to apply to linkages and truss structures though.
mh, addition for OP:
if this isnt helping and change in p is big enough:
maybe you can narrown down obstruction location by doing pressure measurements in intervals.
Pete engr student here. What is your gas flash comp or gravity? Also the operating conditions of the pipeline?
Well what I'm working on is more of a global search technique, so it's not quite comparable to gradient descent or evolutionary algorithms. Thanks to some clever mapping, I map the entire enumerated search space onto a number line, such that similar model combinations are located near each other, then form a statistical model for where in the search space the best solutions occur. I'm still debugging it, but it ought to achieve very good results very quickly.
But it's rigorous
>sucking thousands of kilometres of pipes
Send out a sound pulse and measure time to reflection.
If the obstruction is practically a total blockage you can use the fill rate and pressure buildup to determine volume between compressor and block. Divide by cross sectional area and voila: you get the distance.
Ultrasonic transducers on the wall can measure propagation speed also in the fluid. This will change with fluid pressure. Measure at various places along the length (binary chopping, say) and locate where there is a transition.
> use the fill rate and pressure buildup to determine volume
I think this is what I am looking for. Its a natural gas pipeline with a total blockage.They wont buy shit so, can I get the information I need to solve this from a sales meter that calculates million cubic feet/day? Without buying new equipment I can tell what the static (line) pressure, differential pressure (through an orifice plate), flow rate, total volume, specific gravity (in this case .9789) and temp. I think the pipe diameter stays pretty constant in the underground sections but there are some 45's when it comes above ground for the pig launchers/blowdowns.
Can you do my work for me, user? What equation would I use to calculate flow rate and pressure buildup to determine volume?
I am equally astounded. I can't into thermodynamics because I am a born untermensch (I still tryhard) but I am leagues beyond the people running the region in simple reasoning. It's amazing to me they don't kill or disable more of their workers.
1. A gas company has an obstruction in a pipeline. Find the lateral surface area of the pipe in order to tell how much pipe the crew will need to knock on. Put your answer in terms of pi. (15 points)
>p.s.: give me a job
Oh, and if (against all odds!) this is patentable, you have the right to be named as an inventor on the application. It does not matter if you are intern or employed, paid or unpaid.
In some jurisdictions you have also a right to a "reasonable compensation" for the invention.
Are there pressure gauges stationed at different spots in the pipe, for regular checks/maintenance? Assuming you have the ability to close off gas flow through the pipe, you can read the pressure change simultaneously at different positions along the pipeline. If there's a significant obstruction like you say there is, the latent pressure in the pipe will equalize at significantly different rates on either end of the blockage. Find the two pressure gauges which seem to contain the length of pipe with the blockage, then you can use more exact methods like sonic testing.
Don't worry about the math, just pour a few gallons of this stuff down there and start pumping. I'll invoice you tomorrow when you're up and running.
Can you reverse the flow? That might pull it out the other end.
dude, you have no idea what you're talking about, do you?
Well, I have lots of ideas that are patentable, but seeing as how I have a net worth of -$20k I don't think I can afford to file. So right now, work > patents.
In some jurisdictions you might be obliged to inform your employer if you have made a patentable invention and then it is up to them to determine of they wish to patent it, keep it a trade secret or let it go. There are a few ifs and buts here but that is the simple explanation.
And keep in mind that oil tech does a lot of patenting and have a fair bit of patent conflicts. Since journalists consider oil to be "dirty" and "unglamorous" they prefer to talk about Apple patent conflicts. Still, the conflicts are simmering there.
Earlier ones also tended to squeal as the seals rubbed against the inside of the pipeline.
This is what I would have thought was the standard system for pipelines. Should just start with whatever gauge along the flow is the first to show a reading that deviates from the norm and the normal one before it. The blockage would have to be between those two points. I would also have thought that you would be able to close such a section of the pipeline off and then service it.
>Please help with a gas pipeline problem I am having in my introductory fluid mechanics course.
Fixed that for you, dipshit.
This, OP. What the fuck.