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53

Probably the biggest drivers behind using methane as a fuel is that it is abundant in natural gas and is (currently) mostly useless as a chemical feedstock. Ethane makes up a few percent of natural gas and can also be obtained as byproducts of petroleum refining, but the big difference from methane is that ethane is extremely useful in chemical synthesis (...


39

In both cases, there appears to be a confusion of terminology between common and technical uses. We commonly use methane and propane for cooking (and home heating), but not ethane. I would expect ethane to be suitable for this, being in between the two, but I've never heard of anyone using it for this purpose. Why is that? In reality, anyone using ...


17

Well first off, pure ethanol is hygroscopic; it attracts water, to the point that it will pull it out of the air. Ethanol and gasoline will mix, but ethanol, gasoline and water will not; the ethanol-water mixture will come out of solution and settle on the bottom of your tank. Add a little oxygen to the mix, and you get rust. However, the more common side ...


17

Higher $\mathrm{RON}$ seems possible. Yet the boiling point rises accordingly while heat of combustion remains roughly the same. Here are two compounds that fit all posed criteria. \begin{array}{|c|c|c|c|c|} \hline \mathbf{Molecule} & \mathrm{mp\ \mathrm{(^\circ C)}} & \mathrm{bp\ \mathrm{(^\circ C)}} & \Delta_\mathrm cH_\mathrm m^\circ\ (\...


17

There's a NASA report that looks into this: "ON THE SOLUBILITIES AND RATES OF SOLUTION OF GASES IN LIQUID METHANE", Hibbard and Evans, 1968 and concludes that such mixtures are possible. Starting on page 8: Figure 5(a) presents the curves for oxygen, argon, carbon monoxide, and nitrogen. Also shown are the two experimental values for nitrogen. ...


12

Diesel engines vs. gasoline engines Diesel engines don't rely on spark plugs, but they still work by igniting the fuel to generate a force that moves a cylinder in the engine. The air/fuel mixture in a diesel engine is ignited by the compression of the same cylinder during the "compression" stroke. That is, like most gasoline engines in cars, diesel ...


12

Usually when we say something "burns", it's being oxidized. In the case of carbon dioxide only the oxygen can be oxidized, by displacing it as the element; that requires fluorine or a sufficiently powerful fluorinating agent. Carbon dioxide supports combustion, acting as the oxidizer instead of being oxidized, with some active metals such as magnesium. ...


12

To add to the Bob's excellent answer (and expand a bit on my comment there), I've found two other potentially interesting papers to peruse. The first is R.J. Hodges and R.J. Burch, Cryogenics 7 112-113 (1967), titled "The equilibrium distribution of methane between the liquid and vapour phases of oxygen". They note a "very high solubility of methane in ...


11

No: trying to catch up with 100+ years of technological optimizations in your kitchen won't be an economical enterprise. Store-brought batteries are standardized and relatively inexpensive. Power from an outlet is even less expensive (by one or two orders of magnitude). On the other hand, in many places you can save on electricity by going solar. Even if ...


11

tl;dr: You are likely to see more soot, $\ce{CO}$, $\ce{H2}$, less of $\ce{CO2}$ and same amount of $\ce{H2O}$. There are different type of combustion that you can talk about. For example when you mix fuel and oxidizer before burning them, it is referred to as premixed system. For example a gas cooking range, gas turbine engines, IC engines, etc. On the ...


10

I'll leave the science fiction/fantasy to more creative contributors, but I think your conditions can be replicated in our not-so-bizzaro world (although those over at the Chemistry World Blog might be able to convince you that our world is a bit bizzare). If you returned from watching some videos, consider the following chemical equation: $$\ce{CH4 + 2O2 -...


10

The answer depends on what do you mean for ancient people. There are a lot of reactions that could produce gas for ejecting projectiles. The most common was the mixture of sulphur, potassium nitrate $\ce{KNO3}$ and carbon that is known as gun powder and has been reported to be used since the IX century in China. If you want some less efficient and not used ...


9

I recommend the @Stanley Yu own answer, as I admit I was not particular familiar with the shape of the ON number curve. It is done by an extrapolation of the critical compression ratios of mixtures 0-100% of isooctane and 100-0% of n-heptane for ON values <0 and >100. If, just illustratively, 100% isooctane had the critical compression ratio 1:20, 90% ...


8

Methane has many lovely properties. It's a very dense source of energy. It is plentiful, it seemed to be cheap to extract (until we worked out the real cost), and similarly seemed to be cheap to transport long distances. It can be stored for many months in vast quantities. But. It's a greenhouse gas - a powerful one at that. On a 100-year horizon, it has ...


8

Combustion is (usually) chain radical reaction with heavy branching. More branching means faster combustion and less branching is slower combustion. And detonation is wave of super-fast combustion. So, if you can suppress branching or deaden some branches, you can increase durability of air-fuel mixture. Actually, this means, that some radical trap is ...


8

Ethanol clearly can be used as a fuel. But there are several reasons why it isn't. First is simple economics. Ethanol costs more to produce than gasoline: oversimplifying only slightly, fermentation is more complicated than simple distillation. Those countries that do use mixtures of ethanol in gasoline do so for "environmental" reasons (which are not ...


7

You have 1 mol $\ce{C}$ reacting with 1 mol $\ce{O_2}$ to give 1 mol of $\ce{CO_2}$ What you need now is something to relate weight and mol. This is called molar mass, notated with the letter M, and has the unit g/mol. You'd just look that up on the internet, but it's calculated from the weight of the atoms in each molecule. If a molecule weighs 32.2 units, ...


7

During WWII many cars were powered by a gasogene engine, which transformed wood or charcoal into a synthetic gas composed by $\ce{CO}$, $\ce{N2}$, $\ce{H2}$ and $\ce{CO2}$. Thus the use of $\ce{CO}$ (albeit not as a pure gas) as a fuel is not something new (the former use of piped coal gas for house heating and cooking has already been mentioned above). I am ...


6

... are homemade batteries ... a practical alternative for powering your appliances ...? No, those type of batteries don't have enough energy to power more than a small light bulb or a transistor radio. If fact the light bulb probably won't stay lit for more than 10 minutes. An LED would be much better. You need at least 30 car batteries to power your home ...


6

Techron is a detergent based on PEA, polyeter amine. It is a complex synthetic molecule that will basically 'loosen' and 'solve' deposits in your fuel system. They then become part of the fuel-air mixture and burn in the combustion chamber with it. Be it in the carburettor, the injectors, the valves (for indirect injection vehicles) or the combustion chamber....


6

Diesel fuel The difference between gasoline and diesel fuel lies in the length of carbon chains. Gasoline and diesel fuel are examples of hydrocarbons, molecules made up purely of hydrogen ($\ce{H}$) and carbon ($\ce{C}$) atoms. Simple examples include $\ce{C_3H_8}$ (propane) and $\ce{C_8H_18}$ (octane). Gasoline contains compounds with carbon chains ...


6

Gas to liquid technology is known, but propane isn't a good choice of end product The idea of converting natural gas (which is mostly methane) into liquids is widely used not least because the earth has, inconveniently, located the best natural gas fields some way from the places that most want to use natural gas. Right now (in 2016), though, it seems it ...


6

I'll address you questions in order: 1) Yes, that is basically the correct reaction, although not quite balanced; here is how I would write it: $$\ce{2H2(l) + O2(l) -> 2H_2O(g)}$$ 2) Ideally, if there were no side reactions, then yes, this particular reaction is "polution free", and the only product is water. 3) You are correct in your ...


5

What you have is classified as a Mg-air battery. You can read more about it here : https://en.wikipedia.org/wiki/Category:Metal-air_batteries These are a class of primary(i.e. not rechargeable) batteries, where the anodic reaction is a metal being oxidised and the cathodic reaction is oxygen reduction. The reactions are: $\ce{Mg → Mg^{2+} + 2 e^{-}}$ on ...


5

$\mathrm{KNO_3(s)}$ can oxidize charcoal without sulfur. It needs a "hot" primer through to get the reaction started. Sulfur's role is to lessen the ignition temperature. See section in Wikipedia article. Since the reaction isn't complete and has a number of possible products bthere isn't an exact chemical formula for black gunpowder burning. The ...


5

Historically, this sort of process has been done with the Fischer–Tropsch process. The core of this process is to use "syngas" (a mixture of $\ce{CO}$ and $\ce{H2}$) in the presence of a catalyst to make higher molecular weight hydrocarbons: $$\ce{(2n + 1) H2 + n CO → C_{n}H_{2+2n} + n H2O}$$ Under normal conditions, this will actually make mostly ...


5

Carbon monoxide has been used as a fuel but not usually by itself. The reason why we don't use it much now is that there are better, safer alternatives. Before the widespread use of natural gas as a fuel (which consists mostly of methane) many cities piped coal gas (sometimes called town gas) to consumers as a fuel. Coal gas is made (obviously) from coal ...


5

One of the earliest use of Black Powder was crude large-bore handheld guns (early China). And, actually much more, to quote a source: Other Song military applications of gunpowder included primitive hand grenades, poisonous gas shells, flamethrowers and landmines. The first artillery pieces were rocket tubes made from hollow bamboo shoots, but these were ...


4

I used Zn + S as a teenager. It is a lot safer than Al, and you can mix it cold. Stick to solid propelants because it's simpler, safer and smaller. You don't want an explosion but something very quick burning. Mix the two fine powders well. You can mix them in a thick plastic bag or wide mouth bottle and shake until you see an even color in all the mix ...


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