Energy generation from Aluminium and Water: Feasible or snake oil?

[Shpaget]

10 hours ago, sevenperforce said:

I don't see anyone suggesting this is a free lunch

I do. This Delhi boy Tirthak Saha.

Quote

And we produce hydrogen at a significantly lower cost, slashing operating expenses by up to 80%.

Are we going to ignore the cost of producing Al that is consumed in the process?

Scrap aluminum is not trash. Recycling Aluminum requires ~5% of the energy required to make it from ore, but this process turns that scrap and recyclable Aluminum into something very similar to raw ore. That huge amount of energy required to refine Al is something Tirthak Saha pretends is not part of his hydrogen production process.

[DDE]

39 minutes ago, Orc said:

If you want an example of aluminium and water yielding a lot of energy look up ALICE (https://en.wikipedia.org/wiki/ALICE_(propellant). I am sure this is something Kerbals would do.

Hold the water, I prefer the lOx slurry. You don’t need the hydrogen and get some use for the oxygen extracted from alumina... once you reclaim your graphite.

Bummer, @nyrath, what have you done with this image?

[magnemoe]

1 hour ago, Shpaget said:

I do. This Delhi boy Tirthak Saha.

Are we going to ignore the cost of producing Al that is consumed in the process?

Scrap aluminum is not trash. Recycling Aluminum requires ~5% of the energy required to make it from ore, but this process turns that scrap and recyclable Aluminum into something very similar to raw ore. That huge amount of energy required to refine Al is something Tirthak Saha pretends is not part of his hydrogen production process.

This, reusing aluminium is very efficient. 
See this as an efficient but non reusable battery. Know military was very interested back 30 years ago. Back then batteries was far weaker and military is fine with non reusable if its good.

[Orc]

Greets all

DDE wrote: 

> Hold the water, I prefer the lOx slurry. You don’t need the hydrogen and get some use for the oxygen extracted from

> alumina... once you reclaim your graphite.

 

Not a bad looking idea. A couple of issues might arise:

1) LOX. LOX seldom remains LOX anywhere in the universe for very long, unless you are actively cooling it. Water is mostly solid and occasionally liquid or gaseous through most of the universe.

2) Graphite. Refining CO2 back into graphite is not easy. It's got its own energy burden. The only process I remember involves CO2 + H2 + lots of thermal energy. I think there might also be a reaction that uses CO and CH4 but I'm not sure.

Still, cool.

 

Regards

Orc

[DDE]

26 minutes ago, Orc said:

The only process I remember involves CO2 + H2 + lots of thermal energy.

Yeah, that’s the one usually paired with Sabatier for a chemical closed life support loop. Not sure how it scales up - but the refinery above already has plenty of heat to go around.

Edited February 25, 2019 by DDE

[Scotius]

For two weeks (rougly) of every month. After that you need to stop production or switch to other heat source (nuclear reactor, what else). Or build your installation in one of permanently sunlit spots on the Moon.

[YNM]

And I think we were talking of using them on the Earth ?

[kerbiloid]

Spoiler

Aluminium.
For somebody - scrap. For another one - treasure.

By selling this treasure, one can just pay his electric bills.

 

Edited February 25, 2019 by kerbiloid

[mikegarrison]

On 2/24/2019 at 1:01 PM, Shpaget said:

Electric arc furnace for steel can be powered by nuclear.

Cement is also produced by baking stuff, which doesn't really demand burning fossil fuels. It could nuclear. Hypothetically, you don't even need the electrical energy step.

Cement is produced by baking off the carbon from calcium carbonate. Even if the "baking off" part were done using carbon-free energy, the chemical reaction itself produces so much CO2 that cement production is pretty much the largest non-combustion source of man-made CO2.

[kerbiloid]

3 hours ago, mikegarrison said:

Cement is produced by baking off the carbon from calcium carbonate.

Lime is.

Afaik, cement is basically a baked mixture of milled alumina, silica, and other stuff.

[mikegarrison]

55 minutes ago, kerbiloid said:

Lime is.

Afaik, cement is basically a baked mixture of milled alumina, silica, and other stuff.

If by "other stuff" you mean "lime", than that would be correct. Seriously, besides the energy involved, baking the CO2 from limestone to provide lime for cement is a major source of CO2.

See cement there at 2.3% of all US greenhouse gases? Half comes from "energy" but the other half from "industrial proccesses" is the CO2 that is baked out of the limestone.

[kerbiloid]

8 minutes ago, mikegarrison said:

If by "other stuff" you mean "lime", than that would be correct.

I mean milled feldspar and gypsum. Various sorts have different composition. 

(Yes, CaCO3→CaO is a part of this.)

Edited February 26, 2019 by kerbiloid

[mikegarrison]

Anyway, the point is that concrete-intensive projects like nuclear power plants and hydro-electric dams may not make a lot of CO2 in operation, but they still have a non-negligible lifetime CO2 footprint.

[kerbiloid]

40 minutes ago, mikegarrison said:

Anyway, the point is that concrete-intensive projects like nuclear power plants and hydro-electric dams may not make a lot of CO2 in operation, but they still have a non-negligible lifetime CO2 footprint.

According to wiki/ru, 1 t of aluminium requires 600 kg of carbon electrodes.
Current production is 40 mln t / year.

I can hardly imagine a nuke plant weighting a million tonnes.

[Shpaget]

1 hour ago, kerbiloid said:

I can hardly imagine a nuke plant weighting a million tonnes.

Well, it's in the ballpark.

https://www.elp.com/articles/2017/12/containment-unit-concrete-poured-at-plant-vogtle-nuclear-expansion.html

Quote

In 2017, more than 57,000 cubic yards of concrete have been placed for the Vogtle project, bringing the project's total to about 545,000 cubic yards, enough concrete to build a sidewalk from Miami to Seattle.

Also, Wikipedia has numbers on Hoover dam and power plant.

Quote

A total of 3,250,000 cubic yards (2,480,000 cubic metres) of concrete was used in the dam before concrete pouring ceased on May 29, 1935. In addition, 1,110,000 cu yd (850,000 m3) were used in the power plant and other works.

But it doesn't mater. About 80 million tonnes of cement produced in USA accounts for 2,3% of total CO2 emissions (chart mikegarrison posted above). That's, what 20? 30? nuclear power plants worth of cement each year, so if the cement production was doubled and this excess used to make nuclear power plants it would only increase total CO2 emissions by 2 percentage points, but the reduction of emissions from lower usage of fossil fuels would amount to about 6-10 percentage points each year (rough calculation based on total USA energy production and 20% of it produced in 60 nuclear power plants). In 10-15 years worth of cement production all power from fossil fuels could be transitioned to nuclear at the cost of 2% increase in CO2 emissions until the first reactors come online. After that it's lower emissions each year.

[mikegarrison]

I am not opposed to nuclear power or hydro-electric projects. I just want people to understand the whole picture.

[StrandedonEarth]

Well, the Site C hydro project on the Peace River in northern BC will have over half the dam made of earth-fill. But that earth isn't being moved with electric vehicles. But it will be a net-clean project in the long run

Edited February 26, 2019 by StrandedonEarth

[mikegarrison]

1 minute ago, StrandedonEarth said:

Well, the Site C hydro project on the Peace River in northern BC will have over half the dam made of earth-fill. But that earth isn't being moved with electric vehicles...

I live in hydro power country, and it's great for cheap, low-carbon electricity, but it has some other bad environmental effects, especially on salmon. That free lunch just keeps on being elusive.

[StrandedonEarth]

7 minutes ago, mikegarrison said:

I live in hydro power country

Likewise.

7 minutes ago, mikegarrison said:

but it has some other bad environmental effects, especially on salmon.

Which is why there's supposed to be fish ladders built around them. Another bad side effect is that any drowned vegetation releases methane as it rots, an even worse GHG. I used to fish on Williston Lake (the biggest dammed lake in the world, at least at the time), and streams of bubbles were all over the place. If I'd realized it was CH4, I would have tried to light them. So hydropower isn't always the best thing for reforming alumina...

A fishing buddy used to joke that at least one good thing about a nuclear war would be that the dam would get nuked, the lake would drain, and he could go recover his fishing lures....

[mikegarrison]

31 minutes ago, StrandedonEarth said:

Likewise.

Which is why there's supposed to be fish ladders built around them. Another bad side effect is that any drowned vegetation releases methane as it rots, an even worse GHG. I used to fish on Williston Lake (the biggest dammed lake in the world, at least at the time), and streams of bubbles were all over the place. If I'd realized it was CH4, I would have tried to light them. So hydropower isn't always the best thing for reforming alumina...

A fishing buddy used to joke that at least one good thing about a nuclear war would be that the dam would get nuked, the lake would drain, and he could go recover his fishing lures....

They also disrupt the natural siltation of the river and raise water temperatures. None of this is good for the fish. But it's still probably better overall than a giant coal power plant.

Many of the older dams here in Washington State were built without fish ladders, which is a problem. Hard to retrofit. We recently tore out two very old dams in what is now Olympic National Park. This was actually the world's largest dam removal project. It's a topic of great interest to study how the environment and the fish react to this.

https://www.usgs.gov/news/moving-mountains-elwha-river-still-changing-five-years-after-world-s-largest-dam-removal

https://www.nps.gov/olym/learn/nature/elwha-ecosystem-restoration.htm

Edited February 26, 2019 by mikegarrison

[YNM]

9 hours ago, mikegarrison said:

concrete-intensive projects like nuclear power plants and hydro-electric dams may not make a lot of CO2 in operation, but they still have a non-negligible lifetime CO2 footprint.

True.

Additionally for hydropower, you're using extra land area for the reservoir, which count into the ecological footprint; nuclear power requires long-lasting care for their waste, which will expend more resources. These two are by far the largest problem they create.

We probably use much more concrete, cement and binders to make highways, railroads, other infrastructures and normal buildings combined anyway.

Edited February 27, 2019 by YNM

[kerbiloid]

https://en.wikipedia.org/wiki/List_of_countries_by_cement_production

Wiki tells about 4 bln t / yr.

It's anyway much greater than any kind of energetics and aluminium.

[DDE]

8 hours ago, mikegarrison said:

I live in hydro power country, and it's great for cheap, low-carbon electricity, but it has some other bad environmental effects, especially on salmon. That free lunch just keeps on being elusive.

Don’t get me and @kerbiloid started on the impact of the Soviet school of using cascades of huge artificial reservoirs because of focusing on rivers with next to no altitude gradient.

 

We’re not talking salmon. Just the Rybinsk reservoir is 150 000 km2 of arable land or producing forests sunk, 130 000 people relocated - and who knows how many thousands “expended” during construction (mortality amongst the “workforce” bounced from 4% to 35% in 1942).

[mikegarrison]

12 hours ago, DDE said:

Don’t get me and @kerbiloid started on the impact of the Soviet school of using cascades of huge artificial reservoirs because of focusing on rivers with next to no altitude gradient.

 

We’re not talking salmon. Just the Rybinsk reservoir is 150 000 km2 of arable land or producing forests sunk, 130 000 people relocated - and who knows how many thousands “expended” during construction (mortality amongst the “workforce” bounced from 4% to 35% in 1942).

See also the Columbia. Lots of "run of the river" dams, with no part of the river above Portland actually free-flowing except for the bit around Hanford Nuclear Reservation (which they saved for a different kind of environmental problem).

https://en.wikipedia.org/wiki/Columbia_River#Dams

The Columbia and its tributaries produce almost half the hydro power in the US, and the irrigation projects turned Eastern Washington into a tremendously productive agricultural region, but the environmental cost was huge.

Edited February 27, 2019 by mikegarrison

[DerekL1963]

On 2/26/2019 at 3:33 PM, mikegarrison said:

Many of the older dams here in Washington State were built without fish ladders, which is a problem. Hard to retrofit.

At the Tacoma Power dams on Lake Cushman and Lake Kokanee they built literal elevators to move the salmon past the dam...