How do I optimize hydrogen production with elecrolyzers?

[suxkar]

Hello, I need to produce more hydrogen for my rockets and I couldn't find any updated threads on how to optimize hydrogen production with elecrolyzers.
Power and water are not a problem, and I will just vent oxygen into space since I don't need it. Still, I would like to optimize the uptime on electrolyzers.
Can someone suggest such a design?

[Steve Raptor]

Well, here is mine:

 

Spoiler

It works on the same principle of a SPOM, you create a hydrogen only area above the electrolyzer using an atmosensor.

This design starts off as oxylite production and hydrogen storage device and then transition into LOX / LH production.

For LOX, the oxygen pipes are re-directed away from the refinery and into a new cooling room and the hydrogen tanks as well, when the hydrogen tanks are full, the rest of the hydrogen goes to the hydrogen generator.

Hydrogen is pumped to the gas storage on the right, from there it goes into liquid hydrogen processing.

[Yoma_Nosme]

Uptime is determined by air pressure around.

[fishoutofwater]

need 2 pumps for every electrolyzer, and maybe this: https://forums.kleientertainment.com/forums/topic/100796-electrolyzer-and-pump-layouts/

[bobucles]

Optimizing electrolyzer uptime is such a headache. Just assume you'll never get 100% output and use more electrolyzers. They're dirt cheap and there's no implicit penalty for it.

[NicholasTheGr8]

@Yoma_Nosme is correct.  I watched a youtube video by @Brothgar where he beats that dead horse for hours.  Maybe he will pop in and leave a link, as I cannot find the video right now.  Ultimately, he achieved maximum gas production by adding a bunch of gas pumps to pull a vacuum on the room.  That near-negative pressure was enough to squeeze a tiny bit more gas out of the setup, but was very costly due to all of the pumps running.

[OxCD]

I think flooded electrolysers are the only solution so far to get 100% production uptime.

[KittenIsAGeek]

I go for pump uptime rather than electrolyzer.  2 pumps pull 1kg/s of oxygen, which leaves 126kg/s of hydrogen for a third pump.

[chemie]

10 minutes ago, KittenIsAGeek said:

I go for pump uptime rather than electrolyzer.  2 pumps pull 1kg/s of oxygen, which leaves 126kg/s of hydrogen for a third pump.

This.  Building an electro is essentially free and they only consume when running.  So optimal designs are really about fully utilizing the gas capacity.  In your case, I would maximize for H2 versus Kittens comment about O2 but it depends on design intent.

[KittenIsAGeek]

Well, without using tricks, the only way to improve hydrogen production is to remove the excess oxygen.  So the more oxygen you produce and remove, the more hydrogen you're left with.

[avc15]

3 hours ago, NicholasTheGr8 said:

@Yoma_Nosme is correct.  I watched a youtube video by @Brothgar where he beats that dead horse for hours.  Maybe he will pop in and leave a link, as I cannot find the video right now.  Ultimately, he achieved maximum gas production by adding a bunch of gas pumps to pull a vacuum on the room.  

It's good enough to set up for gas separation, and build just slightly more pumping capacity than you need. 2 pumps for the 888 g/s o2, 1 pump for the 112 g/s h2. Control all of them on pressure bi-stables set to shut off when pressure goes below 300g or so (whatever the lowest pressure you're still pumping full packets)

 

You'll get around 95% throughput.

 

For 100% you have to use gas/liquid conflict like some others were saying but that also used to cause some gas deletion.

 

Not sure on the exact state of things right now.

[zzKratoszz]

13 minutes ago, avc15 said:

For 100% you have to use gas/liquid conflict like some others were saying but that also used to cause some gas deletion.

This is the only way I've found that doesn't cause massive gas deletion. I once did a comparison awhile back and a flooded electro made I think about double the hydrogen that a normal open air 3 pump design did. Edit: Using the same amount of water that is.

[storm6436]

Yeah, it's kinda overkill and done to produce O2 for dupes, not H2, but this "works."   I'd need to record the duty cycle of the 2nd H2 generator, I could probably tell you exactly how much hydrogen it is producing, but it's not the rated 112g/s.  By the numbers, this setup should have a 210 g/s demand while supplying 224 g/s , but it certainly doesn't.  Next time the automated gen kicks in, I'll keep an eye on the consumption rate and update.

Also, contemplating expanding the upper/lower chamber to be even with the middle and seeing if the increased flow availability helps.  As it stands, the previous incarnation of this setup only kept sufficient space open for the top/bottom pumps.  That extra two tiles does seem to have increased H2 yield.

[DemainaNyx]

Partially submerging an electrolyzer in two kinds of liquids prevents it from over pressurizing so it will run 100% of the time.  It also allows it to automatically sort hydrogen and oxygen easily.

For getting the liquid there, I like to use pipes to more easily control the amount of liquid in each chamber.  Run a pipe, fill with bottom liquid, deconstruct the pipe, repeat for top liquid.  I normally use pipe bridges over the airflow tiles so I don't have extra liquid, but I doubt it would cause much issue.  Below is my oxygen room for most of my bases.  I set it up with 4 electrolyzers from the beginning and just connect them to power whenever I need them.  You either need to vacuum out the room from the beginning or prime the system to get the gases where you want.  I vacuum the room and they automatically sort with hydrogen at the top.  

It is a bit of work to set it up, but works really nicely. 

Some issues that can arise from it though.  One is freezing the liquids.  I was cooling the hydrogen/oxygen in this room and actually froze the top layer of water, which broke the system.  Second is stray packets of other gases.  If different gases get into this system, they can block the ports and break the automated sorting.  Third is over pressurizing an area.  Once I had more than 10K oxygen in the bottom room and it pushed the water aside and filled in the hydrogen room, hence why there is an atmosensor in the oxygen room to turn off the electrolyzers once a certain pressure is reached.  With more liquid per chamber, that might be less likely to happen but I've never bothered testing how much liquid I can get away with without flooding them.

Those are the only issues I've discovered so far, and they are all easily managed.

[zOldBulldog]

I probably watched every video there is on electrolizer setups.   The most efficient and compact design I came across is the "full Rodriguez" at the end of this video (the image on the right on the title screen) .  It is for a SPOM but you just want the electrolizer chamber piece.

If you were building a SPOM it would produce 3 1000g/s full pipes of O2.  You can run the calculations to determine how much of a hydrogen pipe it will fill.

NOTE:  This is more of a show-and-tell than a true step-by-step tutorial that shows you how to build it, but if you use the pause button a lot and analyze it carefully you should be able to duplicate it.  

I don't think a true tutorial exists for this design but it looks good enough to be worth the effort.  I plan to switch my base O2 production to this myself, after I finish my current projects.