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Petroleum boiler / high yield, low heat waste

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Hi guys!

My current build will require around 10kg/s of petroleum, so here's a build for refining petroleum with a variable demand, with minimal heat waste, and able to draw down the heat source to something around 600C before needing to dig out hot rock & flood with magma again.

Last time I built one of these, the game wasn't multi threaded, and we didn't have radiant pipes. Some much better tools now.


What do you mean, minimum heat waste?

Well, just that - I'm supplying crude oil at 90C. Counter flow heat exchange (the copper radiant pipe flowing up through that serpentine on the left) means that I'm delivering crude to be boiled at 390C, and petroleum dripping out the bottom is exiting just about 108C. Delta T, 18C - the heat source (my magma on the right) does much less work this way, and I'm moving far less heat into the people space, meaning there's less cooling to do later.

Edit to the delta T: that number was skewed by my build being kind of young (insulated tiles are still heating up) and not running at full capacity. After I've turned it up to 10kg/sec and let it run a long time, I'm sitting on a petroleum tank at 123C and an oil inlet of 80C. Petroleum has a higher heat capacity than crude oil so you can't make the outlet temp equal the inlet temp. (nakomaru said below that the equivalent temp increase is 28C for converting crude to petroleum, seems reasonable)



Very simple automation. Let crude in if the petroleum tank isn't full.

Run the inlet on a bistable (SR latch with two fluid sensors in the petrol tank) because each time you shut it down some heat gets wasted and you'll have to dig out hot rocks left over from your working fluid much sooner.

Close the heat transfer doors if the thermo sensor on top senses less than 410C, open them up again immediately when it senses more than 410C.

Petroleum boils at 400C, so petroleum around 410~420C flows out the left

The boiler needs to have a very high total heat capacity

You'll notice I have a one-thick layer of molten lead doing the work. Behind that, a row of granite headstones (Thanks for that idea). Further still, aluminum temp shift plates. The top row of metal tiles is made from aluminum, the doors & bottom row are made of steel.

It's important to pack as much heat capacity in there as possible, because when the doors are shut things heat up a little bit too fast. But we don't want to just make it conduct less heat.

More heat transfer will mean that when the magma solidifies & cools, I'll be able to get full petroleum production out of this machine to a much lower working temperature. When I finally have to dig out that rock, I want it to be as cool as possible. My goal is 600C or lower.

So in the meantime I need to live with a very high total heat transfer rate (making things difficult to control temps precisely)

To improve temp control I need absolutely as much total heat capacity as I can get.

Vacuum is the best insulator

Since we won't be going inside any of these rooms much I made some pretty elaborate airlocks. When a bunch of dupes go in at once, pressure inside stays less than 1mg.




You'll notice I'm only running at about 5kg/sec right now. I'm gradually turning it up, but I'm nowhere near the capability of this system right now.



Eventually you're going to draw enough heat out of that magma that you won't be able to refine petroleum at full speed anymore.

At that point, you have to shut off the inlet, and open the maintenance doors below. Have fun digging out some hot igneous rock, then close maintenance doors and open up the magma inlet again.

I haven't finished that room yet but I'm envisioning a 2-high pool of petroleum for cooling some auto-miners, with temp sensors to provide cooling water flow and stop digging when temps start to get too high.

I'll set up that room when it's time, but from the beginning it needs to be built & vacuumed out.




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The conversion of crude oil to petroleum at 677K generates 28K worth of oil equivalent heat. I wonder if that 18K number is really steady state. Maybe I'm wrong but it doesn't seem possible without bleeding heat elsewhere (and you aren't)

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1 hour ago, LucidFugue said:

I love that you build this right over the neural vacillator and computer desks. Just re-purposing the office, don't mind me. 

don't forget the graves.  LOL  I wonder how many dupes died in constructing this.  I see 9 tombstones.

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8 hours ago, nakomaru said:

The conversion of crude oil to petroleum at 677K generates 28K worth of oil equivalent heat. I wonder if that 18K number is really steady state. Maybe I'm wrong but it doesn't seem possible without bleeding heat elsewhere (and you aren't)

No it is not steady state, Now that I've run it a long time, here are the steady state numbers. The petroleum tank is sitting on 123C/ my oil supply has changed to 80C for some reason (it should go back to 90 eventually).

What this person is on about is that petroleum has higher specific heat capacity than crude oil so you can't get a perfect cooler. My original numbers were skewed by things like.... the insulated tiles still hadn't heated up yet, and I was only running it at 40% capacity.

But if you're right and the best case is 28K I'm satisfied with these results.

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One small update, a liquid level sensor is no good for the controls to the magma flood doors. I learned this by experience when I let a pool of magma out that ruined the whole base.


Had to jump through a dimensional portal to the next reality to recover from that one.

So to answer the question above, how many dupes died building this system? Zero, in this universe.

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