The invention relates to a four-in-one
biogas fermentation device and method. The device comprises a first-stage dry
fermentation mechanism, a second-stage wet
fermentation mechanism, a folding gas storage bag, a
sunlight greenhouse and a
solar water heater, wherein the first-stage dry fermentation mechanism comprises an annular dry fermentation tank which is filled with a feed liquid and is arranged in the
sunlight greenhouse, a net box which is filled with a material and is soaked in the feed liquid, and a water seal cover which is hermetically arranged at the top of the net box; the second-stage wet fermentation mechanism comprises a wet fermentation tank which is communicated with the dry fermentation tank, a
heat exchanger which is arranged in the wet fermentation tank, and a
biological membrane which is fixed in the wet fermentation tank; a gas guide
pipe is arranged at the top part of the wet fermentation tank; the folding gas storage bag is arranged at the top part of the wet fermentation tank and is communicated with the gas guide
pipe; and the
solar water heater is arranged at the top part of the
sunlight greenhouse and is used for supplying circulating hot water to the
heat exchanger. By using the four-in-one
biogas fermentation device and the method provided by the invention, the problem that a
sludge pump is blocked easily is solved, and by combining the use of
solar energy and the sunlight greenhouse, energy sources are saved, the degradation time of a
fiber material is shortened, the utilization ratio of a fermentation
raw material is improved, the content of
methane in
biogas is improved, and the comprehensive utilization ratio of biogas residues and biogas
slurry is increased.