The liquefaction pressure of biogas is so great that a gas tank can't bear it. Even a tank that can withstand such a large pressure is too dangerous, so it is not feasible to store biogas basically like a gas.
"Biogas liquefied gas" method
(1) American ExxonMobil Company (patent application number: 998 156 13.2)
A method for producing a pressurized methane-rich liquid stream with a temperature of-1 12 degrees Celsius (-170 degrees Fahrenheit) and a pressure sufficient to keep the liquid at or below its boiling point. The pressurized methane-rich gas to be liquefied is provided in the methane-rich liquid stream with the temperature lower than-155℃ (-247 F), and its pressure is increased, and the pressurized methane-rich liquid stream is introduced at a certain speed, thus producing the methane-rich liquid stream with the temperature of-12 C (-170 F).
(2) Biogas liquefied gas (patent application number: 2006101151.2).
It is proved that biogas is metamorphic and liquefied. This technology is a specially designed "special measurable biogas liquefaction tank", special gas compressor and its automation system with a certain amount of low molecular weight hydrocarbon mixture below C5 as catalyst cosolvent. After the biogas is deeply liquefied, it is put into a steel cylinder to obtain the product "biogas liquefied fuel" with biogas as the main component.
(3) Producing natural gas from biogas (patent application number: 2007 100 13535.2)
Natural gas is made from biogas, which is compressed to make its pressure change from normal pressure to 0.85MPa；; The compressed biogas is desulfurized and decarbonized, and the methane after decarbonization is more than or equal to 90%; The recovery rate of methane is more than 98%, and natural gas is produced. It can enter the urban natural gas pipeline network, and can also be compressed into vehicle fuel to replace gasoline.
(4) Production of dimethyl ether fuel from biogas and its method (patent application number: 20075438+000 1032.438+0).
A fuel for preparing dimethyl ether from biogas and its method are characterized in that biogas is used as raw material, and after compression, desulfurization (H2S) and partial removal of carbon dioxide (CO2), it is converted into synthetic gas consisting of hydrogen (H2), carbon monoxide (CO) and carbon dioxide (CO2) by steam in a conversion device under the action of a catalyst, and the synthetic gas is pressurized by a compressor and first synthesized under the action of a catalyst with two functions of methanol synthesis and methanol dehydration. Liquefied fuel containing dimethyl ether was obtained by using low molecular weight hydrocarbon and C5 mixed solution as cosolvent.