The perils of a serviceable petroleum boiler

[Gus Smedstad]

This is my first-ever volcano-powered petroleum boiler. All my previous ones used thermium aquatuners. The basic design's lifted straight from John Francis's video on the subject, but modified to allow for internal access to correct errors. 2-high passages in the counteflow heat exchanger have been fine, but easy access to the heating chamber proved to be a problem.

It ran out of magma, leaving 1 ton of 1400 C debris at the bottom of the heating chamber. A dupe ran in to use it, and on the way out, passed through the drop of oil acting as cooling medium for the robominer. The oil flashed over to sour gas, filling the heating chamber, and causing the robominer to immediately overheat since a lot of the energy went from the gas into the miner.

If you're not familiar with magma mechanics, it looks like there's plenty of magma, but in fact if I opened the upper door, none would flow through. Magma's highly viscous, and it requires about 150kg in a tile before it will flow to an adjacent tile. I quite regret the design of the magma tank, because as designed, there's a lot of unusable magma backed up. At this point it'd be very difficult to correct that, though.

The image here is midway through recovery. I've forced the upper door closed, just in case, and partially blocked the heating chamber with a granite tile so I can replace the cooling drop for the miner without spilling petroleum into the bottom. I plan on putting in a door in the waterlock so I can restrict dupe access.

Main issues with the boiler seem to be:

* Not very heat efficient if turned off periodically, which is why I ran out of magma. I've got automation shutting off the crude oil flow if my petroleum storage backs up. In continuous operation, the last pipe segment's about 390-395 C, which is great, but on startup it's more like 350 C.

I'll try and address that one way or another. Long term solution's probably a bank of petroleum generators to burn any excess beyond what I can store.

* The hot debris in the waste chamber is hotter than I want. The mine-and-recycle cycle is set to 430 C (again, per the video), but the actual debris is about 7 tons at 600 C. That's a lot of wasted heat. I don't know why the temperature is so much higher than the trigger point on the sensor.

* No way to transfer heat if all that's left in the heating chamber is debris. It's normally a vacuum, so that 1 ton of 1400 C debris that caused the accident wasn't transferring heat to the oil chamber.

[EricS]

It's not a straight lift though.  Jon Francis's design had a drop from the volcano before the lava blade in order to get the right flow in the lava blade. In fact, he commented that he had to make the drop one tile higher in order to get the right flow, so it is important. That may be why you're not getting magma through when you open the door.

 

He also had a two high chamber for the lava blade for all but the first tile (the one that actually made a blade instead of a tank.  I don't know if that's important, though I've seen times where it seemed that water flowed differently depending on whether the tiles above the flow were open atmosphere or solid tiles.

 

Aside from that, it looks like it should work.  I've thought of adapting his design to cope with issues I had when using it or to achieve goals that he didn't have, and I may get back to it, but right now I'm looking at something significantly different.

[Gus Smedstad]

I just re-checked the video. The uppermost door part, the part which contacts the magma, is identical. The door is on the same level as the magma blade, not one tile below it, so the flow mechanics should be the same. My robo-miner is one tile higher, but that's not really relevant to the magma regulator.

His chamber for the magma blade is 1 tile high. That's actually why mine is 1 tile high - I wasn't sure if it mattered for flow mechanics, so I decided to play it safe. If I were to do it again, I'd scrap the whole magma blade thing entirely, because the regulator puts a limit of 2 tiles of magma regardless.

I'm referencing the September 2019 video - I believe that's the most recent one where he steps through the mechanics, though of course he builds these pretty often in later "Let's Play" videos without explaining them.

In any case, when the magma tank is reasonably full, flow's not a problem. It's only when it's at the limit, as in this screenshot, that is has any effect. It looks like a lot of surplus magma, but due to magma's viscosity, it's actually the bare minimum.

When there's enough magma in the tank, and it's been running for a while, it works perfectly fine. It's just the edge cases (dupes grabbing debris, on/off operation) which seem to screw it up.

[Steve8]

The distance between the edge of the volcano and the drop is very important. It's supposed to be much shorter. A normal magma blade is only 10 or 11 tiles long due to the viscosity. That's why he wants 9 tiles between the edge of the volcano and the door

He runs into that issue himself here: https://youtu.be/LEhb8d67dOo?t=1226

 

[EricS]

Sorry, I didn't explain it clearly.  The blade in your design is at the same level as the bottom level of the volcano itself.  Francis never does this, and in this video he states that the amount of the drop from the volcano is important.

 

I'm not going to claim to understand the nuances of this.  This also shows the other difference, though I don't know if that one is important or not, that being that in every one of his designs I've seen, the space above the magma blade is open, unlike your design.

 

The other difference I see is that you have a constructed tile blocking the magma drop.  I didn't mention this, because I don't see how it would work with that block there, so I assumed that that was part of maintenance.

 

I've implemented this petroleum boiler, and I didn't have problems running out of magma even though I was running it off a minor volcano or with the debris being too hot.  I'm just trying to figure out why you're having problems and I'm not.  I don't think it's the change in the heat exchanger, as long as you're running this off a full volcano rather than a minor one.

 

[nakomaru]

Maybe precision magma pumping can help you. And there are plenty of ideas about how to separate and utilize the heat from the igneous rock in there as well.

[Steve8]

1 hour ago, EricS said:

I'm not going to claim to understand the nuances of this.  This also shows the other difference, though I don't know if that one is important or not, that being that in every one of his designs I've seen

It has to do with how far the magma flows: https://youtu.be/YWQcaus9if4?t=52

That is an old video, but it shows the magma's viscosity. The drop isn't absolutely needed in all situations, but it does help by giving it some extra force. Especially when the magma tank is getting empty. The more important thing is the distance between the volcano and the door. If you don't have the drop you can shorten that a bit.

[Gus Smedstad]

It turns out that my magma shortages were entirely due to the magma tank. It backs up pretty quickly and produces overpressure in the volcano.

This has nothing to do with "force" from the drop. It's because the volcano will stop producing very shortly after magma gets deep enough to cover the output point. I solved this one with a door pump.

As you can see, there's a significant amount of magma that was being lost in the prior setup.

3 hours ago, EricS said:

The other difference I see is that you have a constructed tile blocking the magma drop.  I didn't mention this, because I don't see how it would work with that block there, so I assumed that that was part of maintenance.

Correct. I even said as much.

On 3/8/2021 at 10:33 AM, Gus Smedstad said:

The image here is midway through recovery. I've forced the upper door closed, just in case, and partially blocked the heating chamber with a granite tile so I can replace the cooling drop for the miner without spilling petroleum into the bottom.