Process and apparatus for anaerobic digestion
AssigneeNorth Carolina State University
InventorJason C. H. Shih
Life of this patent
Estimating the term…
Abstract
A process for the anaerobic digestion of organic carbonaceous material is disclosed. The process includes the steps of (a) hydrolyzing organic carbonaceous material to produce a digester stream including hydrolysis products; (b) subjecting the digester stream to a first methanation phase operating at thermophilic conditions to produce a gaseous product including methane; and (c) subjecting the digester stream to a second methanation phase operating at mesophilic conditions to produce further gaseous product including methane, and to recover heat. An apparatus for the anaerobic digestion of organic carbonaceous material is also disclosed.
Claims24
A process for the anaerobic digestion of organic carbonaceous material, comprising:
- (a) hydrolyzing the organic carbonaceous material to produce a digester stream comprising hydrolysis products;
- (b) subjecting the digester stream to a first methanation phase at thermophilic conditions to produce a gaseous product comprising methane;
- (c) subjecting the digester stream to a second methanation phase at mesophilic conditions to produce further gaseous product comprising methane and concurrently recovering heat from said digester stream during said second methanation phase by directing an aqueous liquid source through a heat exchanger in said digester stream during said second methanation phase to thereby heat said aqueous liquid source;
- and
- (d) directing said recovered heat into step (a) of hydrolyzing to thereby heat the organic carbonaceous material by directing said heated aqueous liquid source from step (c) into fluid communication with said organic carbonaceous material of step (a).
A substantially longitudinal apparatus for the anaerobic digestion of organic carbonaceous material, comprising in series:
- (a) a first chamber having both a carbonaceous material inlet in fluid communication therewith and an aqueous liquid inlet in fluid communication therewith, said first chamber for containing carbonaceous material, aqueous liquid, and a source of bacteria, said bacteria being capable of digesting carbonaceous material to produce hydrolysis products;
- (b) a second chamber in fluid communication with said first chamber for containing the digester stream, said second chamber having a source of anaerobic bacteria therein, said bacteria being capable of converting said hydrolysis products to methane gas;
- and
- (c) a third chamber in fluid communication with said second chamber for containing the digester stream, said third chamber having a source of anaerobic bacteria therein, said bacteria being capable of converting said hydrolysis products to methane gas, said third chamber further comprising a heat exchanger, means for directing an aqueous liquid source through said heat exchanger to thereby heat said aqueous liquid source and means for directing said heated aqueous liquid source from said third chamber to said first chamber to transfer heat from said third chamber to said first chamber concurrently with methane gas formation to thereby heat said organic carbonaceous material.
Dependencies are inferred from the claim text.