The best replacment for gasoline is ?

That's a bug, not a feature. Imagine a crash in a tunnel where all that NG was release "within seconds" - and then ignited.

 

Log in or Sign up to hide all adverts.

Most tunnels have large fans that draw out air by the tons so if the gas were to leak it would be gently whisked away and not much would happen. The big problem is with regular car gas tanks exploding or diesel catching on fire. That doesn't get drawn out like natural gas would. Also the flames from natural gas wouldn't last long for they would burn so quickly there wouldn't be much for the fire to use to keep going.

 

Log in or Sign up to hide all adverts.

"Burn so quickly" = "massive explosion." Fuel-air bombs use this same principle to efficiently destroy large structures.

Here's a video of a flame from a natural gas leak burning quickly. You are correct in that there wouldn't be much for the fire to use to keep going after the initial event.

 

Log in or Sign up to hide all adverts.

That is a whole house with probably 30,o00 CU FT of natural gas building up before it blew. This is a very large structure that had no way to remove the gas before it blew. Leaving the gas water heater on would be a bad idea because the pilot light could go off and back on again which would cause a build up of gas.

 

Solar. You don't have to grow it or dig it out of the ground and the sun is going to be around a long time. I don't care if we all are riding electric bikes. I'd rather have slow and clean than fast and polluted.

 

As the Lightning LS-218, Optibike 1100R and the Tesla model S "insane mode" have demonstrated, those two are not the only options.

 

No. An explosive mix of natural gas and air is very powerful and only a small volume (less than half a small kitchen) will destroy the house. Here a few weeks ago in NYC a tiny initial volume leaking from an under ground pipe line did this (took down two brick apartment buildings and killed 8.):

Please Register or Log in to view the hidden image!

In small part of a second the gas under pressure, like it would be in car's tank, added energy to the explosion.

In an automobile collision that opens a small crack in the fuel tank, the typical case, the fuel slowly leaks out if it is a liquid and never explodes as it drips on the ground unless there is absolutely no wind** - never achieves an explosive air-fuel mix; however, if it is natural gas, it ALWAYS quickly achieves an explosive fuel air mix at least near the leak.

* And the number of pipeline explosions is a tiny fraction (< 1%, I'm sure) of the number of building blown apart by natural gas leaks.

** My first job (other than paper boy) was vacation replacement for transmitter engineers*** at Radio WCHS. That required back then a first class commercial license. I probably was the youngest in US to ever get one. (Tough 4 hour FCC exam.)

One completely windless day I poured a little gasoline on the trash in 55 gallon drum the station burned its trash in as it was full. Then noted I had forgotten to bring any matches, so went back to get some. Two or so minutes later when I threw the lite match into the drum, I saw a tongue of flames about 15 feet long extend from the drum, fortunately, not in my direction. I. e. accidently I had made a fuel air mix that was unconfined, so just instantly burned, but did not explode.

*** WCHS is a 24/7 powerful (50,000W) station but when one engineer was on vacation the remaining three drew a lot of double time and some triple time pay. The chief engineer / manager was patient of my MD dad and knew I was a radio ham (W8IJM) and smart. He promised me at least 12 weeks work in summer (not school time) at same pay as the adult engineers got if I could pass the exam. I studied, and passed on the first try, which less than half who took it did. It was a great job - not much to do, but sit in chair and read books with volume turned up high so if we went off the air, I would notice it. When I knew I had passed, I sold my paper route to another boy (Recommened him to the distributor.) as I was getting about a 20 fold step up in salary.

 

Er: if a house had 30,000 cu ft of methane in it, there wouldn't be any air in it.

Methane has a lower explosion limit of 4% so a 30,000 cu ft house only needs 1,200 cubic feet to fill the entire house up enough to reach it. But obviously, as Billy said, it won't fill evenly and even just a kitchen is enough for a big explosion.

Methane has an energy density of 6 MJ/ cubic foot or 57 MJ/ kg, which is more than 10x the energy density of TNT. Filling-up a 15x15x8 kitchen with just 4% methane equals 15 lb or thirty sticks of TNT. (or 40 sticks of dynamite).

Now, we already use natural gas and other gases for fuel: my house is heated by propane instead of natural gas, for example. Propane would probably make a better fuel for cars because at 25C the vapor pressure (pressure of the liquid/gas mix) is only 10 Bar, which is a lot more manageable for a tank than 200 Bar for methane.

 

Natural gas is in high supply and uses lower pressures to flow than propane.

We still aren't getting away from fuels that will eventually be depleted one day. I say we should be concentrating more on renewable energy types of fuels rather than always trying to use things that use depleting fuels.

 

P vs T table for propane and photo/ facts on widely used Natural Gas tank for cars:

Please Register or Log in to view the hidden image!

Please Register or Log in to view the hidden image!

Usually installed inside the car's trunk.

I am almost certain that the 3600psi standard was chosen as that is the common pipeline pressure in cities - I.e. there is no need for filling/ distribution station to compress the natural gas they sell. The G after PSI in the table is for "gage" i.e. not normally used as all know one commonly speaks of how much above atmosphere is what tank pressure means, but they are being careful - so no one thinks their pressure is absolute. I.e. at PSIG = 0 there is no stress on the tank.

Thus even on a hot 130F day the propane tank pressure is lower than the car's natural gas pressureby factor of 3600/257 = 144 ! Yet as it is liquid not gas the energy density are about the same - too lazy to get it exactly, but nearly sure a propane tank of same volume with 80% or more in the liquid state holds more chemical energy.

 

Too late to correct, I notice near end of post 50, the final 4 was repeated. I. e. Common natural gas pressure is 14 times greater than propane pressure.

 

Yes, and since propane is a byproduct of both oil and natural gas, supply is pretty high right now too. But no, I don't think either propane or natural gas should ever be a wide-use replacement for gas in cars.

Not sure what you mean by that but when it comes to burning it in the end-use, they use about the same pressure. Most appliances are convertable between the two.

 

My point was that using depleting resources today make those people coming up behind us more susceptible to running out of them. We should be trying to get away from those kinds of resources and find alternative ways to get renewable kinds of fuels as hydrogen would be for once you burn it , it reverts back to water which can be reused over and over.

 

That's true of methane and gasoline as well. You can synthesize them both from CO2 and water. It just isn't efficient in either joules or dollars.

 

Bicycle.

"Comparing energy used per passenger-mile (calories), they found that a bicycle needed only 35 calories, whereas a car expended a whopping 1,860. Bus and trains fell about midway between, and walking still took 3 times as many calories as riding a bike the same distance."

http://www.treehugger.com/bikes/whats-the-worlds-most-energy-efficient-vehicle-a-bicycle.html

"In terms of the amount of energy a person must expend to travel a given distance, investigators have calculated it to be the most efficient self-powered means of transportation.[1] In terms of the ratio of cargo weight a bicycle can carry to total weight, it is also a most efficient means of cargo transportation."

"From a mechanical viewpoint, up to 99% of the energy delivered by the rider into the pedals is transmitted to the wheels (clean, lubricated new chain at 400W), although the use of gearing mechanisms reduces this by 1-7% (clean, well-lubricated derailleurs), 4-12% (chain with 3-speed hubs), or 10-20% (shaft drive with 3-speed hubs). The higher efficiencies in each range are achieved at higher power levels and in direct drive (hub gears) or with large driven cogs (derailleurs)."

"A human being traveling on a bicycle at 16–24 km/h (10–15 mph), using only the power required to walk, is the most energy-efficient means of human transport generally available."

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