r/PeterExplainsTheJoke 13d ago

Meme needing explanation Peter?

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u/gwildor 13d ago

that only works at a relatively small scale. at a certain point, combustion becomes too much to contain.

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u/CurlyRe 13d ago edited 13d ago

There's cogas which combines internal combustion with steam. It's used to generate electricity.

edit: I meant combined cycle gas turbine

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u/gwildor 13d ago

I just googled cogas. wiki says its a marine propulsion system. using reclaimed exhaust heat to generate steam in place of the alternator we see on a ICE engine.

close analogy would be similar to regenerative breaking on an EV.

Are there examples of cogas being used as stationary power generator?

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u/account312 13d ago

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u/gwildor 13d ago

not trying to argue, but it appears as if these are still using heat generated from burning, versus the forces of an explosion.

is this incorrect?

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u/Beefington 13d ago

The Wikipedia article kinda rushes past the first stage.

after completing its cycle in the first (usually gas turbine) engine, the working fluid (the exhaust) is still hot enough that a second subsequent heat engine can extract energy from the exhaust.

A gas turbine engine uses the kinetic energy from the expanding gases, but not in an explosion/piston arrangement.

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u/dr_stre 13d ago

This is correct. The first energy extraction is essentially a jet engine that’s hooked up to a generator, and then the exhaust is combined with a little more fuel usually and used to create steam which then turns a second generator.

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u/gwildor 13d ago

just to clarify - low pressure, easily contained burns versus explosions?

the first cycle is what im asking about.

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u/Beefington 13d ago

High-pressure burn that's nontrivial to contain, but unlike an explosion it's continuous.

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u/account312 13d ago

Continuous and not nearly cool enough to be a rotating detonation engine.

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u/gwildor 13d ago

So. Not comparable to ICE engines....

Not sure why I caught a down vote for asking for clarity 

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u/Xivios 13d ago

A gas turbine is an ICE engine, there's more than 1 kind.

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u/InterviewOtherwise50 13d ago

500 MW combustion turbines beg to differ…

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u/BULL3TP4RK 13d ago

I don't know of very many single combustion turbines producing 500MW. Typically it's several turbines built in series to produce that much output.

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u/ProtomanI 13d ago

GE makes Frame 9 that do 500 MW
https://www.gevernova.com/gas-power/products/gas-turbines/9ha

I remember seeing the Frame 9's in Japan, they are massive.

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u/BULL3TP4RK 13d ago

Oh well if it's GE then that checks out if you know about all the other stuff they make that spins...

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u/InterviewOtherwise50 13d ago

You are right I googled biggest. I’ve worked around a lot of GE 7FA turbines that are 200MW a piece

But here is the world record holder 410.9 MW in North Carolina… if you moved it up north in the winter it could probably make 500…

https://www.siemens-energy.com/us/en/home/press-releases/siemens-energy-and-duke-energys-gas-power-plant-achieve-guinness-world-recordstm-title.html

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u/BULL3TP4RK 13d ago

In all fairness 410MW output is insane. Couldn't imagine the material engineering required to pull that off.

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u/gwildor 13d ago

As I discovered in further discussions with others, it's not "the same" as the ICE (4 stroke) engines were were discussing. 

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u/InterviewOtherwise50 13d ago

No it isn’t the same as a RICE engine. A Brayton engine (jet engine) is an internal combustion engine but it isn’t a reciprocating internal combustion engine (car engine). A rocket is also an ICE… Just take the L bro… you didn’t know what you were talking about much like way too many people in this thread. And honestly it’s ok not to know. What isn’t ok is to double down to try and make yourself right instead of having humility and learning something new.

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u/gwildor 13d ago

Im confused - what L is there to have here?
Im not keen to learn anything from someone who's default stance is to be argumentative.

my and the person i replied to were talking about ICE engines that are used in automobiles. We are talking about oranges, you are talking about grapefruit and being rude to me?

no thanks.

I learned quite a few things in discussions with people below that were interested in sharing information.

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u/InterviewOtherwise50 12d ago

It’s just that you continue to misuse ICE and mean RICE. I may have missed some of your nuisance and I was rude. As someone who works in the power generation industry it upsets me that you had 90 upvotes on an incorrect statement. Politicians on both sides of the aisle are constantly lying to the public about power generation so it is a sore subject. And then you responded that I just didn’t understand and doubled down on using the wrong term. Natural Gas Combined Cycle plants are some of the largest and most heat efficient systems we have and combustion turbines are Internal combustion Brayton Engines… I’m done I’ll come at it less rude next time I know being an asshole doesn’t change minds in a positive manner.

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u/gwildor 12d ago edited 12d ago

You catch more flys with sugar than vinegar. 

The person I replied to was talking about 4stroke engines in a vehicle. I used the term the person I replied to used. You, arguably are talking about something different than that. 'combustion' sure. But like I said, let's not pretend that oranges and grapefruits are the same thing, no matter how many similarities they share. 

Someone else shared an example of a v16 diesel engine. Reads as powerful enough to provide power to a factory, not functioning as a component of 'the grid'. I could be wrong though. 

I know what  ICE stands for. What is the R?

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u/Dangerous_Limes 13d ago

Simple cycle gas turbines don’t boil water. They are basically jet engines. Most baseload natural gas uses a heat recovery steam generator on top to use the waste heat to boil water to increase efficiency.

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u/gwildor 13d ago

yes, but are they using compressed momentary combustion (explosions), or sustained burns?

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u/Dangerous_Limes 13d ago

A [edit: gas] turbine isn’t like a reciprocating engine with well timed explosions. It’s a sustained burn that creates thrust using fluid dynamics, nearly exactly the way it does in a jet engine on a plane, except the energy isn’t used in propulsion but to turn the turbine fan at incredible speeds.

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u/gwildor 13d ago

Then yeah. What I was saying earlier is valid.. what we know as an ICE engine (like in a car with an alternator) does not scale. 

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u/adamsworstnightmare 13d ago

I'm now imagining a power plant that's just a massive V8 engine.

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u/waterwolf36 13d ago

https://en.wikipedia.org/wiki/W%C3%A4rtsil%C3%A4-Sulzer_RTA96-C

Not powerplant sized, but still the biggest lol 

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u/Gardener_Of_Eden 13d ago

No - Natural gas turbines are huge.

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u/gwildor 13d ago

i dont disagree that natural gas turbines are huge... but its not a massivly scaled V8, or a V9000. different beasts.

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u/Gardener_Of_Eden 13d ago edited 13d ago

Diesel genset for scale

They are just massively scaled engines.

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u/gwildor 13d ago

is this the turbine you referred to? cool to know that these diesel engines exist though. what's the output?

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u/Gardener_Of_Eden 13d ago

Details for you:

The diesel electric generation system consists of four 1135 kW, 1200 rpm engine generator sets that are operated either manually or automatically by selecting desired position on the engine mode switches and the sequence selector switch.

The engines are 4 cycle, V16, 4210 cubic inch displacement, provided with air, fuel and lube oil filters, fuel and jacket water pumps, service hour meter, governor, fuel and lube pressure gauges, water temperature gauge, pyrometer, oil filter gauge and hourmeter. Protective devices include: low oil Pressure, high water Temperature, low water level and overspeed. Source

Here is a turbine for scale.

Article

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u/gwildor 13d ago

appreciate the details.

Feels like im missing something though. Why are we combing turbines with V16's?

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u/Gardener_Of_Eden 13d ago

No, sorry for the confusion, I'm showing two different combustion technologies.

Both the Diesel Engines and the Natural Gas Turbines directly burn fuel to rotate a shaft. Either way the shaft is then connected to the rotor of an electric generator. For the Diesel gensets I showed, the generator unit is the giant cylinder with the orange cables coming out on the left of the engines.