Can you compress methane

But until manufacturers can find a way to pack more methane into a tank at lower pressures and temperatures, allowing for a greater driving range and less hassle at the pump, passenger cars are unlikely to adopt natural gas as a fuel. UC Berkeley chemists have now developed a porous and flexible material — a so-called metal-organic framework MOF — for storing methane that addresses these problems. The flexible MOF collapses when the methane is extracted to run the engine, but expands when the methane is pumped in at only moderate pressure, within the range produced by a home compressor.

The flexible MOF can be loaded with methane, the main ingredient of natural gas, at 35 to 65 times atmospheric pressure psi , whereas compressed natural gas CNG vehicles compress natural gas into an empty tank under atmospheres 3, psi.

Liquefied natural gas LNG vehicles operate at lower pressures but require significant insulation in the tank system to maintain the natural gas at minus degrees Celsius minus degrees Fahrenheit so that it remains liquid.

Next-gen NG vehicles Long said that next-generation natural gas vehicles will require a material that binds the methane and packs it more densely into the fuel tank, providing a larger driving range. One of the major problems has been finding a material that absorbs the methane at a relatively low pressure, such as 35 atmospheres, but gives it all up at a pressure where the engine can operate, between 5 and 6 atmospheres.

MOFs, which have a lot of internal surface area to adsorb gases — that is, for gas molecules to stick to the internal surfaces of the pores — and store them at high density, are one of the most promising materials for adsorbed natural gas ANG storage. A cross-section through a flexible MOF shows how the chemical structure shifts when methane is absorbed. Among the other advantages of flexible MOFs, Long says, is that they do not heat up as much as other methane absorbers, so there is less cooling of the fuel required.

In order to get a useful amount of gaseous fuel into a reasonably-sized tank, you have to liquify it. Some fuels are easier to liquify than others. According to the textbook Organic Chemistry by Joseph M.

This means that methane has to be cooled to a much lower temperature than propane in order to be turned to a liquid that can be stored in a tank. Propane molecules consist of three carbon atoms bonded in a chain with eight hydrogen atoms bonded to these carbon atoms. In contrast, a methane molecule is just one carbon atom bonded to four hydrogen atoms. Methane molecules have a high degree of symmetry. As a result, they do not have a permanent electric dipole. Remove the gas transfer tube.

Leave the methane gas to cool in the liquid nitrogen tank for at least 48 hours. Check the temperature on the cryogenic tank to verify that the contents are at least negative degrees Celsius. Transfer the cooled methane gas from the cryogenic tank to the pressure vacuum with a gas transfer tube. Open the shunt on the cryogenic tank and on the pressure vacuum. Close the shunts when all of the gas has moved to the vacuum. Set your pressure vacuum to exert 46 bars of pressure on the methane gas.

The methane gas will slowly condense and form a liquid at the bottom of the vacuum. If you release the liquid methane from the pressure vacuum, it will turn back into a gas very quickly. Transport of the gas requires transfer to a container that can maintain the 46 bars of pressure. Andrew Mayfair has written professionally since when his article on patent law was published in the "Loyola of Los Angeles Entertainment Law Review.