Patent ID: 8409439

Claim:
A pressurized digester biogas reactor comprising: a mixing tank having a bottom, sides and a top; a bottom portion of the tank having a smaller diameter than a central portion of the tank; a double channel central draft tube; a pump forcing an inlet fluid downward through a central channel in the double channel central draft tube into the bottom portion of the tank; said central channel having a primary nozzle facing downstream; an outer draft channel housing the central channel; wherein an annular space between the outer draft channel and the central channel forms a secondary channel; said outer draft channel having a secondary nozzle facing downstream; wherein said primary nozzle is located above said secondary nozzle, and both nozzles share a common longitudinal axis; said outer draft channel having an inlet weir for channeling a mixing tank fluid into the secondary channel; wherein the pump supplies a minimum of twenty feet per second flowrate to the inlet fluid; wherein said minimum twenty feet per second flowrate forms a vacuum at a bottom end of the outer draft channel; wherein said vacuum induces the mixing tank fluid into the weir and out the secondary nozzle; wherein a combined flow from the primary and secondary nozzles impinge the bottom of the mixing tank; a slurry in the tank producing a biogas; a pressure controller located at a top portion of the tank to maintain an operating pressure in the tank in the range of about 30 to 100 psi; said bottom portion of the tank having a heater; said pump having an inlet in a central mixing zone of the tank for the inlet fluid; and said central mixing zone having a slurry outlet to release liquids therefrom.