Should we ban kerolox rockets

[DaveofDefeat]

I sincerely hope you're just kidding.

What's next? Dimethyl mercury and dioxygen difluoride?

Just think, if we started using those, nobody would think kerolox is harmful! In fact, it would look absolutely environmentally friendly in comparison.

[MBobrik]

I sincerely hope you're just kidding.

What's next? Dimethyl mercury and dioxygen difluoride?

polonium 210 and botox

[shynung]

Well, if you put it that way...

John D. Clark's book once mentioned a truly crazy propulsion system: a rocket burning hydrogen, lithium, AND fluorine. And guess what it got? 542 seconds of vacuum I_sp, at a chamber temperature of only 2200 K; SSME's went into 3500 K, and only got 453 seconds.

Edited December 20, 2014 by shynung

[lajoswinkler]

Oh, it's almost certainly possible to get a petroleum-like mixture out of cellulose: you would just need to use bacteria, catalysts, or enzymes which promote hydrocarbon chain formation. It wouldn't matter exactly what you get, so long as it's got roughly the same chemical distribution as the fuel of choice. I also disagree with the implication that it must be more expensive than crude oil distillates. If cellulose extraction, transport, conversion, and transport back to distribution centers can be done more cheaply than petroleum extraction, refinement, and transport, it should be cheaper in the end.

Problem being, of course, that right now, it's really hard to devise chemical processes which are cheaper than petroleum extraction. It's like the old joke with lignin: you can make anything from lignin but money. If we can move to all biofuels, nuclear, and renewable, we can go to a net-carbon-neutral situation where each year's carbon production is taken up by the next year's crops, but that isn't going to happen soon for several unfortunate reasons.

Petroleum-like =/= kerosene. That's my point. You can produce stuff similar to it, but real kerosene would take manufacturing each compound found it in, then blending, and that's not really what we're talking about here...

Again, the cellulose thing would require some serious calculations with variables and data we simply don't know here, so it's mostly speculation.

Wrong. Any organic material can be partially pyrolyzed and then converted to hydrocarbon mixture via fischer tropsch.

I don't say it is the most efficient, or even acceptably efficient route, but you can do it. And, if there will be no other carbon inputs it has to be CO2 neutral by definition.

But it isn't kerosene. It might seems like nitpicking, but details matter for engine performance.

good thing that driving fuel synthesis does not place the same demands on the source as power grid base load.

What?

HVDC, or convert it to fuels on site. Your choice.

HVDC won't work. We're talking about much larger distances. Converting to fuels, maybe. Studies are needed.

We are talking about small fraction of the overall energy flow through the system.

It all boils down to Hess' law. CO2 is almost on the bottom of the energy well in our world and compounds that would harvest it are alkalis. Sodium hydroxide is the cheapest alkali made on a massive scale. It's done by brine membrane electrolysis.

We can't rely on chemical processses to salvage that gas. Plants should do it. GM plants, even better.

That is my opinion too, but some people want to avoid the n*** word at all cost. So I say doesn't matter. If you think you can go without it, just go on, your choice. The only restriction is zero fossil carbon.

[Idobox]

Just think, if we started using those, nobody would think kerolox is harmful! In fact, it would look absolutely environmentally friendly in comparison.

Doxygen difluoride is for wimps, real rocket scientists use chlorine trifluoride. For the fuel, I propose acetylene, it's not particularly toxic, but it should make a nice boom, and also melt whatever hasn't been eaten by the ClF3. Also, it would release copious amounts of CF4 (a potent greenhouse gas) and more importantly HF, one of the strongest acids around, and terribly dangerous to living things.

I can't think of a single structural material that could be used for the chamber and bell, or for the launchpad, but it would be very interesting to watch from a distance, upwind.

[EDIT]

I've read about FOOF. My bad, ClF3 sounds very safe by comparison.

Seriously, who in their right mind looked at the formula of peroxide and thought it was a good idea to replace the hydrogen with fluoride?

Edited December 20, 2014 by Idobox

[Starman4308]

Petroleum-like =/= kerosene. That's my point. You can produce stuff similar to it, but real kerosene would take manufacturing each compound found it in, then blending, and that's not really what we're talking about here...

You don't need to make each component of kerosene separately. It's plenty possible to go with chemical reactions which make a variety of compounds. These reactions exist and have been known for some time, they're just not economical yet. So long as what results is roughly similar to kerosene, it should be easy enough to filter out troublesome compounds and come up with a fuel similar to RP-1. You'd probably still have to redesign the engines a bit, but it's unlikely to be a huge changeover.

There is no need to hit RP-1 on the head or make each component separately: slight retools to engines can account for the first, and there's several ways to promote semi-random creation of large hydrocarbons from short hydrocarbons.

[NERVAfan]

I think biofuels are very promising for some applications (where high energy density is important e.g. aviation fuels) but current corn ethanol production isn't really any environmentally better than fossil fuels (since corn growing is fossil-fuel-heavy) and competes with food. What you need is biofuels made from "waste" materials e.g. biodiesel from waste oil or cellulosic ethanol.

Solar... can't be used for base load, true, but it can produce so much energy ultimately that storage might be worth it in the long term.

[MBobrik]

Again, the cellulose thing would require some serious calculations with variables and data we simply don't know here, so it's mostly speculation.

...

But it isn't kerosene. It might seems like nitpicking, but details matter for engine performance.

There is quite extensive research on tuning fisher tropsch to the desired product properties. Producing synthetic kerosene substitute is completely within capability of current technologies. Feel free to check it on the internet.

good thing that driving fuel synthesis does not place the same demands on the source as power grid base load.

What?

Fuel synthesis, as opposed to base power gird load, which is constant, and the power supply has to keep up, can be stopped/ started/reduced depending on current power supply.

HVDC won't work. We're talking about much larger distances.

There is no upper distance limit for HVDC.

CO2 is almost on the bottom of the energy well in our world and compounds that would harvest it are alkalis.

There are many compounds that bind to CO2 almost reversibly, and can thus suck it out of air and release it in concentrated form to fischer tropsch input feed. So the energy cost of this step is not big compared to other steps in the process.

We can't rely on chemical processes to salvage that gas. Plants should do it.

Believe it or not, plants work internally by chemical processes

[Idobox]

We can't rely on chemical processes to salvage that gas. Plants should do it.

Believe it or not, plants work internally by chemical processes

I think what he meant is that big, localized chemical plants are not the right way to tackle the problem. And until we can have mass produce cheap and small fischer process devices, and handle the logistics of collecting all the "waste", it will be much easier to use biomass.

And yeah, harvesting plants and dumping them somewhere is a decent strategy to capture CO2. Harvesting algae might be even more efficient, especially in areas prone to blooms. Some people have also proposed using a LOT of wood in construction.

An ideal solution would be to transform a large quantity of biomass into charcoal and dump it in old coal mines. Of course, it would only make sense if we stopped burning coal in the first place.

[shynung]

But it isn't kerosene. It might seems like nitpicking, but details matter for engine performance.

Rockets and piston engines maybe, but gas turbines aren't very picky about what gets into their combustion chamber, as long as it delivers enough btu/second.

[Bill Phil]

Gas turbines have temp limitations, though... That's why they didn't use hydrogen in the 1930s. And viscosity limitations. Why they didn't use gasoline in the early days.

[Nuke]

Actually that is not longer true, most people on earth is managing pretty decent, not US or EU middle class but more like middle class than poor.

Fun fact is that most people today have an mobile phone

there is a huge difference between owning a cell phone and wasting resources when you dont have to. cell phones are a horrible example. they dont use a lot of power, and mass production means that individually they dont carry a huge carbon footprint (unless you start getting into things like forced obsolescence, which is downright evil and should be illegal). things like running engines and heating water (or anything else for that matter) are where most of the resources (sometimes literally) go down the drain.

as for rocket engines, its not like everyone takes a saturn v to work. a few launches benefits many (through science, technology, communications, etc), so its both justifiable and practical. an suv only benefits its owner. launching a rocket is more like taking the bus.

[MBobrik]

I think what he meant is that big, localized chemical plants are not the right way to tackle the problem. And until we can have mass produce cheap and small fischer process devices, and handle the logistics of collecting all the "waste", it will be much easier to use biomass.

The reason why we do "big, centralized" anything is economies of scale. And there is generally nothing wrong doing things that way, as long as it is the more efficient way.

[Idobox]

The reason why we do "big, centralized" anything is economies of scale. And there is generally nothing wrong doing things that way, as long as it is the more efficient way.

And that's the right approach for many problems, but there is very little CO2 in air, and lots of air, so you need a massive collecting area to do anything meaningful, and a cheap way to concentrate the CO2. And right now, harvesting biomass is the best option.

Capturing CO2 straight out of the exhaust of power plants and other big emitters is also an option, and here, big centralized works.

But of course, the first thing we have to do is to stop releasing so much CO2 in the atmosphere in the first place.

[78stonewobble]

I think biofuels are very promising for some applications (where high energy density is important e.g. aviation fuels) but current corn ethanol production isn't really any environmentally better than fossil fuels (since corn growing is fossil-fuel-heavy) and competes with food. What you need is biofuels made from "waste" materials e.g. biodiesel from waste oil or cellulosic ethanol.

Solar... can't be used for base load, true, but it can produce so much energy ultimately that storage might be worth it in the long term.

I made some quick calculations about solar at some point... If I get this right...

In 2008 the total global energy consumption was 143,851 TWh with electricity being 20,181 TWh a year.

A modern solar power plant that produce 165 GWh a year and can store this energy uses:

51 hectares of solar collectors.

About 200 hectares of total land usage.

28,500 tonnes of molten salt (60 percent sodium nitrate and 40 percent potassium nitrate).

870,000 cubic meters of water a year (or vaporised).

To fully supply the world with solar power, if all things stay the same, would require:

6,222,309 hectares of solar collectors.

24,401,212 hectares of total landusage.

2,477,172,727 tonnes of molten salts.

106,145,272,727 cubic meters of water a year (or vaporised).

Hmm... that doesn't seem right does it? Well, if true... I stick by my original line of thinking, that providing a significant proportion of just the worlds electrical usage from solar power is a pipedream.

Perhaps someone else could provide some information of the additional effects of manufacturing, deploying and maintaning that many solar panels, the molten salts for storage and that much extra water vapor to the atmosphere.

PS: Possibly the manufacture of sodium nitrate and potassium nitrate is quite the bottleneck.

Edited December 21, 2014 by 78stonewobble

[MBobrik]

And that's the right approach for many problems, but there is very little CO2 in air, and lots of air, so you need a massive collecting area to do anything meaningful, and a cheap way to concentrate the CO2.

Air is not like light, you don't need a fixed area. You can let a large volume blow through a small extracting apparatus.

Capturing CO2 straight out of the exhaust of power plants and other big emitters is also an option, and here, big centralized works.

When fossil fuels are banned there wont' be any CO2 producing power plants.

[K^2]

We don't have the resources to replace power production with non fossils in foreseeable future. We don't have infrastructure or readily available fuels for nuclear. Solar would require a huge investment. It takes several years for a single panel to generate enough electricity to cover energy used in production. We can't make that investment upfront right now. And other renewables are nowhere sufficient. We can, and should, reduce our dependency on fossils, we should look into ways to reduce CO2 emissions from existing plants, and we should convert our transit to electricity as much as possible, as that is more efficient. But peak CO2 production is still decades away, I'm afraid. And that's just peak production. Peak levels are easily over a century in the future. If CO2 levels are as big of a problem as some research suggests, we are royally screwed. I'm inclined to think that anthropogenic impact is overestimated, but even then, we're in bad state.

We will need to figure out how to bind CO2, rather than only trying to reduce production. And not only at power plants. That Sahara place looks like it'd make a nice garden with a bit of work.

[MBobrik]

We don't have infrastructure or readily available fuels for nuclear.

Except that we have. Or could have. The only thing that is preventing us from doing so, is radiation phobia of large segments of the population.

It takes several years for a single panel to generate enough electricity to cover energy used in production.

That was true in the eighties. Current solar panels are far more effective. Not to mention the fact that all big solar power plants don't use photovoltaic.

[K^2]

Except that we have. Or could have. The only thing that is preventing us from doing so, is radiation phobia of large segments of the population.

Long term, sure. But short term? We don't have operational mines in the state they need to be to produce required quantities of nuclear fuels.

That was true in the eighties. Current solar panels are far more effective. Not to mention the fact that all big solar power plants don't use photovoltaic.

No, in the eighties, and even well into the 90's, solar panels flat out took more power to make than they could produce in their life time. Solar panels of 90s were effectively means of exporting pollution to China. Solar panels with net positive output are a very new thing. And yes, it still takes several years for them to produce power that went into manufacturing. Run the numbers yourself if you'd like. In some parts of Europe it can take up to a decade. It's better in sunnier parts of the world, but it's still years.

Non-photovoltaic power plants are more efficient, but they are not practical for replacing all, or even majority of our coal plants. They take up a huge amount of land, and they cause environmental problems of their own. Fact that solar farms literally fry birds in flight is just part of the problem. They also work like a giant parking lot, absorbing more heat than whatever environment they replaced, resulting in updrafts. You put enough of these in one area, and you have yourself a whole new means of weather change.

The great thing about photovoltaics is that they can replace artificial surfaces we are already using. Roof tops primarily, but even roads in principle. Covering US roads/highways in photovoltaics would produce several times more energy than US is currently using. I'm pretty sure it'd be true of the world in general, but I have not seen the numbers.

But even that we don't have infrastructure for. Regardless of what you will want to replace coal burning plants with, it will take decades. Even with technology already being in place and even when it makes financial sense to do so.

[MBobrik]

Long term, sure. But short term? We don't have operational mines in the state they need to be to produce required quantities of nuclear fuels.

Do you know what the short term looks like for example in Germany ? Following Fukushima they are shutting down nukes and cranking out coal power plants and opening new coal mines like there were no tomorrow. All that building and mining effort could go into nuclear, instead of coal. As I said. It's all politics, and ultimately (patho)psychology.

No, in the eighties, and even well into the 90's, solar panels flat out took more power to make than they could produce in their life time. Solar panels of 90s were effectively means of exporting pollution to China. Solar panels with net positive output are a very new thing. And yes, it still takes several years for them to produce power that went into manufacturing. Run the numbers yourself if you'd like. In some parts of Europe it can take up to a decade. It's better in sunnier parts of the world, but it's still years.

From what I see, EROEI of photovoltaics is 6.9 which is comparable to oil from tar sands.

[lajoswinkler]

There is quite extensive research on tuning fisher tropsch to the desired product properties. Producing synthetic kerosene substitute is completely within capability of current technologies. Feel free to check it on the internet.

I know what Fischer Tropsch is, I went to college where I studied those things.

Yes, that particular technology does exist, but the viability of it (in terms of money, net energy gain and carbon footprint) depends heavily on every key of the whole production cycle and the actual way of usage. That's the whole reason why some technologies, while being advertised as "green", can actually be highly detrimental for the environment. Example - using PV panels in northern Europe on house roofs.

When you have relatively small net gains compared to standard fuels we dig out of the ground, it's very easy to ruin these things. With powerful, energy dense sources it's a different story.

Fuel synthesis, as opposed to base power gird load, which is constant, and the power supply has to keep up, can be stopped/ started/reduced depending on current power supply.

Yes, and that means it can not be base load power. It can be intermediate to peak load source.

There is no upper distance limit for HVDC.

Well yeah, if you use a crapload of copper to make 1 m thick rods as cables and you don't care about coronal discharge, you could transmit a lot more, but is that viable? Nope. Now, don't pull out the superconductor card. (it's not an argument, just like fusion isn't, because we don't have those)

There are many compounds that bind to CO2 almost reversibly, and can thus suck it out of air and release it in concentrated form to fischer tropsch input feed. So the energy cost of this step is not big compared to other steps in the process.

Give me a few examples of such compounds.

Believe it or not, plants work internally by chemical processes

Really? I thought they worked with fairy dust and magic.

I'm talking about industrial processes, and you're sticking to semantics.

[lajoswinkler]

Do you know what the short term looks like for example in Germany ? Following Fukushima they are shutting down nukes and cranking out coal power plants and opening new coal mines like there were no tomorrow. All that building and mining effort could go into nuclear, instead of coal. As I said. It's all politics, and ultimately (patho)psychology.

True. This is one of the tragedies of modern Germany.

We will need to figure out how to bind CO2, rather than only trying to reduce production. And not only at power plants. That Sahara place looks like it'd make a nice garden with a bit of work.

Turning Sahara into a garden would require enormous amounts of energy (=lots of coal burned), and everything you do there lies against the powerful foot of nature. It's futile, just like it's futile to keep insides of a Venus surface probe at room temperature. Eventually, it will fail.

Sahara is something we can't battle even with GM plants, and even if we could, the consequences for the weather in Europe, western Asia and northern Africa could be disastrous.

So yeah... I'd leave that one alone.

[Starman4308]

I know what Fischer Tropsch is, I went to college where I studied those things.

So then why do you imply that you have to make every component separately? If not Fischer Tropsch, then a newer set of reactions might accomplish the same thing at a lower cost. There is a huge amount of effort trying to do exactly that: come up with a chemical, biological, or hybrid synthesis to produce a petroleum-like mixture at an economical cost.

Even disregarding the possibility of new chemical reactions and processes, eventually petroleum will become sufficiently expensive that Fischer Tropsch will become economical. Hopefully it's because of stiff taxes on petroleum products, rather than petroleum depletion, but eventually petroleum alternatives will become viable because petroleum has become inviable.

[magnemoe]

So then why do you imply that you have to make every component separately? If not Fischer Tropsch, then a newer set of reactions might accomplish the same thing at a lower cost. There is a huge amount of effort trying to do exactly that: come up with a chemical, biological, or hybrid synthesis to produce a petroleum-like mixture at an economical cost.

Even disregarding the possibility of new chemical reactions and processes, eventually petroleum will become sufficiently expensive that Fischer Tropsch will become economical. Hopefully it's because of stiff taxes on petroleum products, rather than petroleum depletion, but eventually petroleum alternatives will become viable because petroleum has become inviable.

As I understand coal to oil makes money with $120/ barrel, making around $120 the highest long term oil price we will get.

No its not more envioromental friendly than drilling, something like cellulose to methanol would be better here.

[Bill Phil]

What are you guys even debating? It's already clear that we shouldn't ban kerolox unless it becomes uneconomic. But it's not going to be banned, just unused.