Author Topic: Rocket propellant from seawater and sunlight  (Read 5694 times)

Offline Ludus

  • Full Member
  • ****
  • Posts: 775
  • Liked: 273
  • Likes Given: 139
Re: Rocket propellant from seawater and sunlight
« Reply #20 on: 04/01/2013 04:28 AM »
I'd think Spacex and a lot if other players including DOD would be interested in this if the costs long term were not much greater than conventional sources.


Not really.  The amount they use is insignificant and would not support the expense of building a dedicated plant.

And why is Spacex singled out?

For what it's worth, I've heard SpaceX is the largest consumer of RP-1. 

As far as whether Fischer-Tropsch fuel can be used to replace RP-1, the RP-1 spec (and even more so the RP-2 spec, which is a tighter spec that sits inside the RP-1 spec) is designed to optimize energy density, boiling point curves, and amounts of certain chemical components (such as sulfur, aromatics, and olefins) which have significant effects on combustion characteristics.  Both were designed around fuels made from particular feedstocks primarily derived from refined petroleum. 

In order to  be a drop in replacement for RP-1, the new fuel would not only need to meet the spec, but in practice closely match the typical RP-1 composition to match RP-1 performance for use on engines qualified for RP-1.  In rocket engines, replicating the exact fuel performance is a much bigger deal than other applications of non-fossil-fuels, such as biodiesel and FT fuel used in cars.  Rocket engines are typically operated in a regime where significant changes in heat production rate, evaporation rate, density, surface tension, viscosity, hydrogen content, or constituent fractions affect mixing and combustion in injectors.  Similarly, significant changes in heat capacity, density,  coking rate, and boiling point curves can effect heat rejection into regenerative cooling circuits.  Energy density also affects the performance of a rocket as a whole as a change in the density would cause the vehicle to store more or less total energy. 

Matching all these characteristics would be relatively difficult to do with synthetic fuels and would require extensive processing of the fuels.  This makes it unlikely that a drop in replacement for existing fuels is feasible. 

This is not to say that a good rocket fuel cannot be made by Fischer-Tropsch, bio-derived, or other alternative processes.  And in fact there are several efforts underway to do this.  See for instance this article which describes some testing that has been done as well as some of the challenges I alluded to above.
http://www.flightglobal.com/news/articles/biodiesel-powers-atlas-rocket-engine-321321/
However, at that point you would be better off developing a new specification, and any program that wanted to use the new fuel would qualify their vehicles specifically to operate on it (possibly alongside RP-1). 


That makes a lot of sense that it's much harder to make drop in equivalents because the standard is designed around refined petroleum stocks and the engines are precisely engineered for the standard.

Probably much easier for methane or hydrogen. I looked at the document for the RP-1 and RP-2 standard and besides the even lower sulfur content (which is easy) had no sense of whether the other fractions were important.

Online KelvinZero

  • Senior Member
  • *****
  • Posts: 3463
  • Liked: 453
  • Likes Given: 113
Re: Rocket propellant from seawater and sunlight
« Reply #21 on: 04/01/2013 07:56 AM »
http://bravenewclimate.com/2013/01/16/zero-emission-synfuel-from-seawater/#more-6020

I'm curious how practical it would be for Canaveral or other major space launch sites to produce rocket propellant on site in a zero net carbon method.

I think spaceports should launch rockets.
Fuel production should be left for petrochemical industry.

I would generally agree. It could make a nice side project though, perhaps purely development. After all they need to develop a reliable lightweight plant for methane ISRU at some point for mars don't they? No petrochemical industries there! Perhaps there is something small and marketable that could be done now without going overboard, just to learn the ropes and perhaps get some more exposure.

Offline JohnFornaro

  • Not an expert
  • Senior Member
  • *****
  • Posts: 9162
  • Delta-t is the salient metric.
  • Planet Eaarth
    • Design / Program Associates
  • Liked: 610
  • Likes Given: 314
Re: Rocket propellant from seawater and sunlight
« Reply #22 on: 04/01/2013 01:40 PM »
However, at that point you would be better off developing a new specification, and any program that wanted to use the new fuel would qualify their vehicles specifically to operate on it (possibly alongside RP-1).

During WWII and for a decade or so afterwards, some Farmall tractors were dual fuel; kerosene and gasoline.  Kero being lower on the hydrocarbon food chain, and thus somewhat less rationed than gasoline.  These are pretty different hydrocarbons, but the engine using them is also less demanding than a rocket engine.

You've listed some of the parameters above, which would have to be considered. 

Would building a "dual fuel" rocket engine be economically and technically feasible?
Sometimes I just flat out don't get it.

Offline JohnFornaro

  • Not an expert
  • Senior Member
  • *****
  • Posts: 9162
  • Delta-t is the salient metric.
  • Planet Eaarth
    • Design / Program Associates
  • Liked: 610
  • Likes Given: 314
Re: Rocket propellant from seawater and sunlight
« Reply #23 on: 04/01/2013 01:43 PM »
SpaceX is mentioned specifically because given the association through Musk with Tesla and Solar City, this sort of benefit may appeal to them more.

The image of the early Ford plants always appealed to me.  Wood, ore, coal, leather, and so forth went in one end of the plant, and cars came out of the other end. 

This association would take the idea of vertical integration one step further; where they also made their own rocket fuel.
Sometimes I just flat out don't get it.

Offline JohnFornaro

  • Not an expert
  • Senior Member
  • *****
  • Posts: 9162
  • Delta-t is the salient metric.
  • Planet Eaarth
    • Design / Program Associates
  • Liked: 610
  • Likes Given: 314
Re: Rocket propellant from seawater and sunlight
« Reply #24 on: 04/01/2013 01:56 PM »
Nobody concerned with CO2 and climate change would question that.

Yes they would.

You're making a logical argument for something you already said was irrational.

Any human activity that increases CO2 levels in the atmosphere is suspect to some people. Messing with the oceans just gives them bonus points.

Not quite sure what you mean. This does not increase CO2 levels in the atmosphere. I don't think it's irrational, just that the main reason it might be interesting is not it's direct impact (since space launches are a tiny fraction of fossil hydrocarbon use) but it's impact on public image and it's utility as a pilot project for broader uses of the same technology.

I think this approach in general has huge promise and it's use for rocket propellant might be an interesting choice for some of the same reasons that Tesla is better off competing with the BMW 7 series than making econoboxes. Rocket fuel is the upscale high image end of the fuel biz. To me people who criticize Tesla for not making cars for the masses don't get the point.

Bottom line:  Easier said than done.

As Ludus points out, recycling carbon between atmosphere and ocean is done all the time naturally.  It is somewhat rational to make the "public image" argument, since people don't see the clouds of exhaust gas coming out of automobiles, except when the guy in front of them has bad rings.  Truth be told, cars pump out exhaust at least as spectacularly as rockets, given their scale, but people literally don't see that.

I could envision a PR campaign around the effort that Ludus sketches out.  Even that would be an uphill fight.  Already, Ludus is encountering opposition from someone who should know something about carbon cycles.

BTW, some people do get that wealthy people are being asked to finance a possible transition to having many more battery operated cars on the road.  Those prices are already falling somewhat.
Sometimes I just flat out don't get it.

Offline Solman

  • Full Member
  • ****
  • Posts: 675
  • Liked: 9
  • Likes Given: 8
Re: Rocket propellant from seawater and sunlight
« Reply #25 on: 04/01/2013 04:45 PM »
Canaveral is sunny, on the sea and has a lot of open space for safety and security that might be used for pv arrays.

No, not really.  It is a wildlife refuge which is not compatible with array farms.

Citation?
Is this based on a study, regulations, or is this just your assertion?
Rooftops, power line right of ways and even perhaps elevated panels over roadways are possible I think, even if regs or research stops placement of panel in refuge areas.

Offline Andy USA

  • Lead Moderator
  • Administrator
  • Full Member
  • *****
  • Posts: 963
  • Los Angeles, California
  • Liked: 117
  • Likes Given: 79
Re: Rocket propellant from seawater and sunlight
« Reply #26 on: 04/01/2013 11:56 PM »
This is NOT a thread for Climate Change. We deal with space flight hardware here.

Offline indaco1

  • Full Member
  • *
  • Posts: 157
  • Liked: 1
  • Likes Given: 3
Re: Rocket propellant from seawater and sunlight
« Reply #27 on: 04/02/2013 12:40 AM »
Would building a "dual fuel" rocket engine be economically and technically feasible?

I think a tri-propellant engine is very attractive.

But it's not for the environment, it's to increase dramatically launch performance (an engine that uses a dense fuel enabling a better T/W during boost phase and an high isp fuel during sustain phase allows to save total engine mass compared to have both specialized engines and optimize tank volume and cryogenic fuel usage). Eg: http://en.wikipedia.org/wiki/RD-701

On the other hand I think syntetic fuels will be very useful for the environment, but it's not for space launch only.
Non-native English speaker and non-expert, be patient.

Offline RocketmanUS

Re: Rocket propellant from seawater and sunlight
« Reply #28 on: 04/02/2013 01:59 AM »
How would they extract the CO2 from ?
1 ) the air
2 ) sea water

From there we already know how to make the CH4 ( methane ) for rocket fuel.
Mars and beyond, human exploration
The grass is always greener on the other side. When you stand on top of the hill you see both sides!

Offline arachnitect

  • Member
  • Full Member
  • ****
  • Posts: 1438
  • Liked: 384
  • Likes Given: 456
Re: Rocket propellant from seawater and sunlight
« Reply #29 on: 04/02/2013 02:00 AM »
http://www.caafi.org/about/faq.html
Quote
Do alternative fuels affect aircraft performance? Effects can be positive or negative. For example, lower density fuels can improve fuel burn but adversely affect payload range. The current fuel alternatives can absorb more heat than existing fuels an important factor for newer aircraft with more electronic equipment. CAAFI is exploring all performance impacts.

Test firing a kerolox engine with synthetic RP-1 might be a worthwhile experiment to try, maybe as a project to keep some of the junior engineers busy and give them some project management experience.

Offline arachnitect

  • Member
  • Full Member
  • ****
  • Posts: 1438
  • Liked: 384
  • Likes Given: 456
Re: Rocket propellant from seawater and sunlight
« Reply #30 on: 04/02/2013 02:45 AM »
How would they extract the CO2 from ?
1 ) the air

All kinds of ways.

Amine (or other chemical) contactor or water-gas shift reactor are possibilities.

Quote
How would they extract the CO2 from ?
2 ) sea water

electrolysis + membrane contactor
http://pubs.rsc.org/en/content/articlelanding/2012/ee/c2ee03393c

I don't see a problem producing synfuels. The problems are more about finding a reason to do it and making sure the synthetic fuel is compatible with your rocket.

Honestly the problem is motivation; there's no reason we couldn't use "net zero" LH2 in rockets (didn't we already have a thread on this stuff?).

Offline Ludus

  • Full Member
  • ****
  • Posts: 775
  • Liked: 273
  • Likes Given: 139
Re: Rocket propellant from seawater and sunlight
« Reply #31 on: 10/03/2017 04:58 PM »
I thought it might be easier to revive this 4.5 year old thread than starting over. The context has evolved somewhat. It would now be about just synthesis of methane and would apply to SpaceX, Blue Origin and ULA using Vulcan.

The SpaceX BFR\BFS system requires this system to synthesize Methane on Mars and in the last IAU speech Elon mentioned the potential to make BFR sustainable by this path.

Methane from natural gas is very cheap and Iím not suggesting that the industry try to switch over to zero net carbon methane at current costs, but that it could take a leadership position by backing the technology development and buying the output at higher prices.

This technology is critical to SpaceXís system and a development cycle on earth advances that.

An example system might be an offshore wind farm built in cooperation with a Power company where the grid takes power when it needs it but off peak excess goes to a power to gas plant.

LOX production from entirely zero carbon power sources like wind maybe affordable at current cost levels and would be a big step in itself.

https://en.m.wikipedia.org/wiki/Power_to_gas
« Last Edit: 10/03/2017 05:13 PM by Ludus »

Offline stefan r

  • Member
  • Posts: 51
  • pennsylvania
  • Liked: 5
  • Likes Given: 12
Re: Rocket propellant from seawater and sunlight
« Reply #32 on: 10/03/2017 06:49 PM »
...
The SpaceX BFR\BFS system requires this system to synthesize Methane on Mars and in the last IAU speech Elon mentioned the potential to make BFR sustainable by this path.

...

An example system might be an offshore wind farm built in cooperation with a Power company where the grid takes power when it needs it but off peak excess goes to a power to gas plant.

LOX production from entirely zero carbon power sources like wind maybe affordable at current cost levels and would be a big step in itself.

https://en.m.wikipedia.org/wiki/Power_to_gas

Cape canaveral is downstream from Orlando, Disney world and a bunch of cattle farms.  Modern cities and cows generate sewage.  You can inject small amounts of a steam/oxygen mix into a large vat of sewage/sludge and thermophilic anoxic bacteria will produce methane.  If you run out of sewage (unlikely) you could add yard waste and other agricultural waste.  This requires trivial amounts of energy which  could be generated with some of the methane produced.  The high temperature generated will kill everything except the thermophilic bacteria which makes it sterile with respect to pathogens. 

Florida has issues with water pollution.  http://www.cnn.com/2016/07/01/us/florida-algae-pollution/index.html  Would be best to concentrate the sewage, generate methane, and avoid the algae bloom.  But if you wanted to you could collect algae (or duckweed) from open waters and then feed them to the bacteria for methanogenesis.  Tourists, turtles and porpoises do not like sludge on Florida beaches. 

Building bioreactors and associated piping costs infrastructure.  There is no need to drain energy from other areas.  If the carbon and hydrogen in our rocket fuel are coming from bodies of water it is best to get it before it dilutes the ocean.  Pipping ocean water inland and then adding energy to process it would be very wasteful. 

Offline Ludus

  • Full Member
  • ****
  • Posts: 775
  • Liked: 273
  • Likes Given: 139
Re: Rocket propellant from seawater and sunlight
« Reply #33 on: 10/03/2017 10:46 PM »
...
The SpaceX BFR\BFS system requires this system to synthesize Methane on Mars and in the last IAU speech Elon mentioned the potential to make BFR sustainable by this path.

...

An example system might be an offshore wind farm built in cooperation with a Power company where the grid takes power when it needs it but off peak excess goes to a power to gas plant.

LOX production from entirely zero carbon power sources like wind maybe affordable at current cost levels and would be a big step in itself.

https://en.m.wikipedia.org/wiki/Power_to_gas

Cape canaveral is downstream from Orlando, Disney world and a bunch of cattle farms.  Modern cities and cows generate sewage.  You can inject small amounts of a steam/oxygen mix into a large vat of sewage/sludge and thermophilic anoxic bacteria will produce methane.  If you run out of sewage (unlikely) you could add yard waste and other agricultural waste.  This requires trivial amounts of energy which  could be generated with some of the methane produced.  The high temperature generated will kill everything except the thermophilic bacteria which makes it sterile with respect to pathogens. 

Florida has issues with water pollution.  http://www.cnn.com/2016/07/01/us/florida-algae-pollution/index.html  Would be best to concentrate the sewage, generate methane, and avoid the algae bloom.  But if you wanted to you could collect algae (or duckweed) from open waters and then feed them to the bacteria for methanogenesis.  Tourists, turtles and porpoises do not like sludge on Florida beaches. 

Building bioreactors and associated piping costs infrastructure.  There is no need to drain energy from other areas.  If the carbon and hydrogen in our rocket fuel are coming from bodies of water it is best to get it before it dilutes the ocean.  Pipping ocean water inland and then adding energy to process it would be very wasteful.

Thatís an interesting alternative. Bio Methane is produced from Carbon in the carbon cycle now rather than from fossil fuels so itís zero net.

The synthetic process wouldnít involve piping ocean water inland but it would be more energy intensive. The reason for developing it is that biomethane isnít scalable for Mars rocket fuel (though Ag on Mars might produce some this way also). On earth power to gas is potentially a method of using excess power from sources like wind in off peak periods.

Offline IRobot

  • Full Member
  • ****
  • Posts: 1155
  • Portugal & Germany
  • Liked: 205
  • Likes Given: 190
Re: Rocket propellant from seawater and sunlight
« Reply #34 on: 10/03/2017 10:52 PM »

And why is Spacex singled out?

He's just following the general rule of NSF, which basically is that the longer a conversation goes on at this site, the chance of Spacex appearing in that conversation approaches 100%.
Reductio ad SpaceXum, Argumentum ad SpaceXum.

Somehow it reminds me of:
https://en.wikipedia.org/wiki/Reductio_ad_Hitlerum

Something like: "SpaceX makes cool rockets, so all rockets discussions must be about SpaceX".

Or, a derivation of Godwin's law:
 "As an online rocket discussion grows longer, the probability of a comparison involving SpaceX approaches 1"
https://en.wikipedia.org/wiki/Godwin%27s_law
« Last Edit: 10/03/2017 10:54 PM by IRobot »

Offline Ludus

  • Full Member
  • ****
  • Posts: 775
  • Liked: 273
  • Likes Given: 139
Re: Rocket propellant from seawater and sunlight
« Reply #35 on: 10/04/2017 01:47 AM »
To be fair SpaceX is now pretty much the focus, much more than 4 years ago for quite a few reasons. Elon Musk has a major interest in climate change and sustainability. SpaceX is pivoting to just build a methane fueled rocket that requires methane synthesis ISRU on Mars. Musk has publically mentioned than BFR can follow this route eventually. No other aerospace company is as connected to the topic.

Online KelvinZero

  • Senior Member
  • *****
  • Posts: 3463
  • Liked: 453
  • Likes Given: 113
Re: Rocket propellant from seawater and sunlight
« Reply #36 on: 10/04/2017 02:48 AM »
The recent spacex presentation also showed a launch pad at sea, and mentioned the intention to generate methane from renewable energy sources.

I think it would be interesting to figure out what sort of surface area you would need around a BFR launcher to launch at least daily. At sea you have access to sun, wind and wave.

.. I suspect a lot of surface area :)

Tags: