[HN Gopher] A molten salt storage solution using sodium hydroxide
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A molten salt storage solution using sodium hydroxide
Author : ericdanielski
Score : 77 points
Date : 2021-12-09 19:58 UTC (3 hours ago)
(HTM) web link (sifted.eu)
(TXT) w3m dump (sifted.eu)
| ortusdux wrote:
| Sounds promising. I work in metal cladding, and there is
| significant interest in molten salt resistant coatings. It
| doesn't sound like this solution would work for molten salt
| nuclear reactors, which is a shame because they could be
| revolutionary if perfected.
| djrogers wrote:
| > It doesn't sound like this solution would work for molten
| salt nuclear reactors
|
| That's actually what the company is researching - this is a
| side-track. Their patent specifically calls out reactors...
| kangnkodos wrote:
| A US company, Ambri, is also working on a molten salt battery.
|
| "The liquid metal battery is comprised of a liquid calcium alloy
| anode, a molten salt electrolyte and a cathode comprised of solid
| particles of antimony"
| adrianmonk wrote:
| > _we cannot let it defocus Seaborg's current mission to power
| regions with poor or no access to renewable energy sources
| through our compact molten salt reactor_
|
| Are there a lot of regions where neither solar nor wind is viable
| but (their new version of) nuclear is?
| danuker wrote:
| Solar and wind need very expensive storage to be reliable. I
| would say these technologies and nuclear complement each other.
| pfdietz wrote:
| Solar and wind do need storage, but if their levelized cost
| of energy is low enough they still beat nuclear. Remember not
| to use batteries for annual load leveling, which some
| dishonest analysts try to do.
| pfdietz wrote:
| High latitude areas away from coastlines are some of the worst
| places for renewables. Eastern Europe and Russia, for example.
| otrahuevada wrote:
| This link here https://aris.iaea.org/PDF/MSTW.pdf seems to
| provide a little bit more info on how they manage to keep the
| corrosion within acceptable parameters.
|
| It involves the addition of an unnamed chemical compound
| functioning as a reducing anode straight into the fuel, which is
| a fairly awesome thing I wasn't aware was possible.
| davidhyde wrote:
| "If we filled up a building the size of the Colosseum in Rome
| with the salt and heated it to 700 degrees, we would actually"
| ... have a whole lot of pissed off Italians on our hands
| ISL wrote:
| It seems to be an unfortunate property of nature that some of the
| most-useful chemical and physical systems are also some of the
| least-friendly.
|
| NaOH, in large quantities, is an unforgiving material. As I've
| read my way into carbon-capture technology, I was saddened to
| find it there, too. HF also comes to mind in this direction (but
| is in another league). There's a correlation between those
| properties that make them useful and those that make them
| dangerous.
|
| The most powerful counterexample to this notion that comes to
| mind, though, is water. What a spectacular chemical, one that is
| so useful we have built ourselves from it, yet we can also swim
| in it for hours without concern for any adverse effect beyond
| temporarily-wrinkly skin. (While it's less-relevant for thermal
| solar, it's darn good at heat-capacity, too! :) )
| saulrh wrote:
| I mean, water is also aggressively hostile. We're just really
| well adapted to it. Even pure water will turn metal into rust
| unless you're using special alloys. Salt water is so bad that
| even alloys won't save you, you have to depend on sacrificial
| anodes and exotic surface coatings. Steam takes everything bad
| about water and jams the fast-forward button until the tape
| catches fire. There's a reason the first hundred years of steam
| power is basically just a timeline of scientific metallurgy and
| gasket technology.
| lapetitejort wrote:
| Let's not forget about how dangerous oxygen can be. The
| oxygen we enjoy now first caused an extinction event:
| https://en.wikipedia.org/wiki/Great_Oxidation_Event
| dvh wrote:
| Isn't NaOH part of the soap?
| lazide wrote:
| NaOH turns fat into soap.
|
| It's dangerous because you're also partially made of
| significant amounts of fats (and other things), which gets
| very very painful and can make it somewhat difficult to
| continue living when they get turned to soap while still part
| of you.
| moralestapia wrote:
| It's a precursor but there's barely any left of it in the
| final product.
| bell-cot wrote:
| Yes - kinda like (horribly poisonous) chlorine gas is part of
| table salt.
| maxerickson wrote:
| Separate from it's use in the production of soap, it's used
| as a cleaner (often at very low concentrations).
|
| In the production of soap, it is used to break down the fats
| used rather than being part of the soap.
|
| https://en.wikipedia.org/wiki/Saponification
| chris_va wrote:
| (I do some research in this space)
|
| There are lots of cheap ways of storing heat... The capacity cost
| of thermal storage has not been the bottleneck for
| commercialization, but rather the round trip efficiency. This
| seems academically interesting, but I doubt it will be much more
| than that.
|
| To a first order approximation, the cost of power from a storage
| system is going to be $/kWh_source_power/efficiency+ammortized
| cost of capital. No matter how cheap the second term is (and it
| can't be that cheap unless someone invents a 10x cheaper
| turbine), the first term tends to make storage uneconomical
| unless your RTE is above ~80%. This will get ~60% at best.
|
| (of course, I could always be wrong)
| new_realist wrote:
| Does this hold true for spilled wind and solar? Does the
| efficiency matter at all if it would otherwise be wasted?
| Xylakant wrote:
| Renewable energy has pushed the spot market prices for
| electricity into the negative last year in germany and UK.
| Soaking up that energy and reselling it later may be viable at
| low efficiency.
| ggm wrote:
| I think you're right to the losses, but didn't consider the
| surplus energy side of things. We now have an
| oversupply/underdemand problem for sufficiently periods of the
| day that time shifting motives by the energy producer outweigh
| the otherwise brutal economics: they can't send the energy
| anywhere else because of transmission system constraints. Then
| need cheap ways to store the energy and loss is probably
| acceptable for the right outcome: better if you can avoid it,
| but acceptable.
|
| Arguably batteries are ideal for the problem. However thermal
| storage systems like this one have good scaling to storage side
| of things: insulation is cheap, adding tanks is cheap. The
| basic turbine cost can supply wallplate stated power, the
| tankage gives duration and you can add as many tanks as you
| have room for.
|
| Alongside simply supplying the energy, batteries are great for
| maintenance of supply frequency but I don't understand how they
| do reactive power. Turbine based systems do reactive power
| really well because of the rotational torque (I think) so
| represent a distinct role in electricity supply stability. (Its
| entirely possible batteries can do this too)
|
| Finally, repurposing of steam turbine based generation sites
| means they have transmission systems, turbines on site and to
| hand: the capex component can be less.
| ok_dad wrote:
| You can do reactive power with some batteries since they are
| all behind inverters that can be designed to do that. The
| Tesla grid batteries (the big ones, don't know about power
| walls) can certainly do it via API commands (you can specify
| real and reactive power components, and frequency control,
| I'm not sure if they can all 3 be run at once though). I'm
| not sure if all battery companies have this feature though. I
| used to control several dozen sites with Tesla batteries via
| their battery control API, though we never used reactive
| power or frequency control.
|
| We still need storage solutions like this for long term
| storage, though, as batteries are mainly used for load
| shifting and short term arbitrage right now, at 6 hours of
| discharge and less.
| pfdietz wrote:
| The round trip efficiency would be a problem for diurnal
| storage.
|
| For long duration storage, capital cost is much more important
| than round trip efficiency.
| pfdietz wrote:
| I wonder if direct contact heat transfer to a gas is feasible
| with NaOH. Avoiding a heat exchanger would be a great cost
| savings.
| Manuel_D wrote:
| What does this add over existing [1] solar thermal plants? The
| approach seems to be roughly the same: heat a material with solar
| power and then operate a heat engine with it. Is storing heat
| generated by photovoltaics better than using solar energy to heat
| material directly?
|
| 1. https://en.wikipedia.org/wiki/Solar_power_tower
| pfdietz wrote:
| Existing solar thermal plants using nitrate salts, which are
| stable up to 550 C or so.
|
| NaOH doesn't boil until over 1300 C. The temperature range from
| melting to boiling is over 1000 C.
| cdeonier wrote:
| When you're dealing with solar (or any renewable really), you
| have to think about the generation of electricity and storage
| of that electricity.
|
| Solar thermal plants can be used to generate energy, but
| they're not great at storing it for dispatch at later times.
| Even the link you provided has thermal storage as a component
| of the system-- you need to figure out how to dispatch
| electricity at night.
|
| What's proposed is a cheaper storage solution, and they state
| it can still provide power after 10 hours.
| Manuel_D wrote:
| Solar thermal inherently has built in storage: the molten
| salt heated during the day continues to provide energy
| through the night.
|
| > Even the link you provided has thermal storage as a
| component of the system-- you need to figure out how to
| dispatch electricity at night.
|
| This is referring to the thermal storage of the molten salt
| tower.
|
| What I'm getting at is why is solar PV -> electricity ->
| thermal storage preferable to solar mirrors -> thermal
| storage. Is solar PV less expensive than mirrors?
| philipkglass wrote:
| Solar PV performs better under imperfect illumination
| conditions. Concentrating solar thermal power can't make
| use of diffuse light on partly cloudy days, whereas solar
| PV can. Solar thermal also has to reach a minimum operating
| temperature before it starts generating steam/electricity.
| PV actually works better on bright, cold days and will
| generate full power the instant an array reaches full
| illumination. These factors, plus the greater mechanical
| complexity and maintenance requirements for thermal solar,
| make it very hard for new thermal solar plants to deliver a
| lower levelized cost of energy than new PV plants.
| s0rce wrote:
| Interesting, doesn't say much about the patented corrosion
| prevention that would enable the storage of the molten sodium
| hydroxide.
| pfdietz wrote:
| Molten NaOH will oxidize many metals, including nickel and
| iron, so maybe cathodic protection?
|
| Yes, that's what it looks like:
| https://www.freepatentsonline.com/y2020/0105424.html
| oconnore wrote:
| It seems unfortunate that it's possible to patent something
| so well documented:
|
| https://en.wikipedia.org/wiki/Cathodic_protection
|
| https://en.wikipedia.org/wiki/Galvanic_anode
| mensetmanusman wrote:
| It's a well documented problem that many groups have tried
| various technical approaches to mitigate over 100,000 hour
| operating windows.
|
| It's not too surprising that a particular implementation
| that has various benefits compared to the existing state of
| the art would be patentable.
| CameronNemo wrote:
| Isn't the point that a patented process is documented as
| part of the patent application? Industrial processes and
| materials seem like a great use of patents from my POV.
| Psychology and biology I'm more concerned with.
| mcdonje wrote:
| Well it says that's the company's core IP, so...
| s0rce wrote:
| Presumably the fundamentals are patented and not a trade
| secret. I could see parts of the manufacturing process being
| a trade secret.
| tosser0001 wrote:
| I always hate the freaking Thunder Sentence: ...
| blah blah blah blah blah. UNTIL NOW.
|
| It's everywhere nowadays and it makes me wince every time I run
| into it. And for whatever reason it's especially annoying when I
| can feel it building up to it, like here which is basically the
| text book example.
|
| Okay, with that off my chest, this technology seems on the
| surface pretty cool and I certainly hope it works out.
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