The invention discloses a large-scale open compound
methane tank, including a fermenting tank (1), a gas collection and storage device (2), and an air feeder (3) connected with the fermenting tank, wherein, the fermenting tank includes a plurality of independent fermenting tanks which can be communicated or disconnected mutually. The
methane tank also includes the gas collection and storage device, the air feeder, a solar warming device, a charging / discharging device and an anti-encrustation device of the
methane tank. When in use, as the structure of the invention is provided with a plurality of independent fermenting tanks, the air can be fed continuously in the
raw material renewal process; the charging / discharging device accelerates the material charging and discharging; the gas collection and storage device of the methane tank has low construction cost, a
software cover can be opened or retracted according to gas production, a gas collection and storage chamber can be changed according to the methane quantity, the pressure in the gas collection and storage chamber can not be too high, and the solar warming device increases the temperature in the methane tank so as to lead the
straw material to produce the methane under the suitable temperature in winter; and a
circulating pump is used for spraying the methane fluid onto the
straw material through a
nozzle so as to avoid encrustation.