Can Co2 be produced to a pressure of 4000 psi in a 50 lt jar by enclosing Yeast/Sugar/H20 in a Jar in ? hours?

Question

The eVolution car uses compressed gas to run a 2 cylinder car. It claims to be emission free. But it’s not as the gas is compressed with electricity, the emission is transferred to the Thermal Plant that produces the electricity to compress the gas.

So I was looking for a benign chemical reaction that can produce a gas in an enclosed cylinder so that it can be used as a compressed gas to power a vehicle. A Gas Pressure of 4500 psi , preferably a Gas that is not noxious or environmentally detrimental. Fermentation produces Co2 which is again a greenhouse gas. How about the gas in Air Bags? Do you know of any chemical reaction that would be viable for this purpose.

http://news.bbc.co.uk/1/hi/world/africa/988265.stm

http://auto.howstuffworks.com/air-car1.htm

Thank you for your time

Answer 1

just butting in to follow up on your acetylene question. Using acetylene as a fuel in a vehicle, all other things aside, would require hauling around 200 pounds of cylinder for each 25 pounds of actual usable acetylene.

The calcium carbide to acetylene reaction, by the way, produces almost as much weight of calcium oxide as you started with calcium carbide. You use a surplus of water to react the carbide so that the temperature won't get to be excessive.

However, in old miner's lamps, a small amount of water was used and the reaction chamber didn't actually get overly hot. The sludge left over was about 75% calcium hydroxide and 25% water, almost a solid.

Using acetylene in non-specialized piping over 14 psig is very dangerous because it may decide to break down its triple carbon bond spontaneously when the atoms are jammed up that tightly.

Not saying it couldn't possibly be done, but I can picture any way that wouldn't cost 10 times as much as gasoline and would be messy and dangerous.

Now...for the question you pose here....

The answers you have already are quite complete and correct; what you want, though, is an easy way to produce large quantities of gases at a pressure high enough to drive a motor. If you are dealing with a turbine, perhaps the pressures don't have to be all that high?

Back to acetylene: in the good old days, when you could walk into a hardware store and buy calcium carbide, so called "fishermen" would sometimes put some carbide and rocks for weight into a glass jar, seal the jar with a lid, poke a hole in the lid, and toss it into a lake. When a little water got into the carbide, it could get got enough to become incandescent, leading to an explosion, killing all the fish for some distance around. The fish floated to the top, the 'fishermen' collected the carcasses and sold them for lots of money.

Not very sporting, and very indiscriminate, even if the goal is food. Sort of like catching dolphins in a tuna net.

Answer 2

Steve's right about the pressure stopping the fermentation before you'd get anywhere near the pressure you want. Also, it'd be too slow and, in the end, too costly in terms of ingredients to ferment, even if it would work.

Sodium azide will indeed produce high-pressure gas, but all other problems aside (and there would be a lot of them!) this approach would never be practical economically.

Probably the best solution would be simply to get the proper equipment and compress ordinary air into cylinders.

As and aside, it is indeed sodium azide (not lead azide) that's used in car airbags. And, the shock of the collision sets off the airbag indirectly, through an electronic circuit with an impact switch. It is not the result of the impact directly on the azide.

Answer 3

Fermentation would not work, because a feedback mechanism would inhibit the yeast. As soon as the pressure reached a small amount, the yeast would stop fermenting. The same thing happens when making wine. Wine tops out at 14% alcohol, because the alcohol inbits the yeast. To get stronger liquors, people distil fermentation broths.

Air bags use sodium azide, NaN3, which explodes with production of N2 gas.

Answer 4

This sounds like an interesting idea, but I believe the reaction proceeds too slowly (order of days) and that the process ends when the alcohol content in the "mash" is 14 percent. You can do the math to figure out the amount of CO2 created and the pressure it would exert. I believe lead azide (Pb(N3)2) is used in auto bags. This compound is widely used in detonator caps. The azide ion is very unstable (sort of like ozone compared to oxygen), and evolves N2 if the jolt of the collision is sharp enough.

Answer 5

This will work -- I use it all the time: Get a screwdriver (flat-head) and gently put it under the edge of the jar lid and try to raise the bottom edge of the jar lid a little bit. Be careful -- you don't want to break the glass. You will hear a little air escape from the jar and the lid will remove very easily. Also, a can opener for a beer can works well too. Just be careful to not actually open the lid with the pointed end of the can opener. But gentle pressure will allow that air to escape from the bottom of the lid edge.