System and method for thermophilic anaerobic digester process

Abstract

A new approach is proposed that contemplates systems and methods to support an environmentally-friendly, “green” thermophilic anaerobic digestion system. The system includes a thermophilic anaerobic digester as well as various independent modular anaerobic units to generate bio-methane from certain organic energy sources, including but not limited to, among other things, green municipal waste, restaurant and organic waste and effluents from industries such as breweries, grocery stores, food processing plants, granaries, wineries, pulp and paper mills, ethanol and biodiesel plants, fat and animal rendering, agricultural field crops, organic sludge accumulation within lagoons and waterways, marine organic matter and animal manure.

1 . A thermophilic anaerobic digester, comprising:
 a cylindrical vessel mounted horizontally above ground and optimally sloped to maximize hydraulic plug flow characteristics and integrity;   a mechanical agitator which components are located  90  degrees apart on a radial basis to propel inorganic material along the bottom.   
     
     
         2 . The digester of  claim 1 , further comprising:
 a digester heating system external to the vessel.   
     
     
         3 . The digester of  claim 1 , further comprising:
 one or more internal baffles to enhance and maintain biological integrity of a plug flow through the digester.   
     
     
         4 . The digester of  claim 1 , wherein:
 a length to diameter ratio of the vessel is set to 3:1 to 5:1 to optimize thermophile and feedstock mixing through a longitudinal agitation arrangement.   
     
     
         5 . The digester of  claim 1 , wherein:
 the vessel length to diameter ratio geometry of 3:1 to 5:1 permits the agitator to achieve optimum thermophile and feedstock mixing without excess agitation.   
     
     
         6 . The digester of  claim 1 , wherein:
 the vessel is designed to maximize hydraulic plug flow characteristics and integrity.   
     
     
         7 . The digester of  claim 1 , wherein:
 the digester requires a short Hydraulic Retention Time (HRT) of 3 to 7 days.   
     
     
         8 . The digester of  claim 1 , wherein:
 the digester achieves volatile solids destruction (VSD) levels of 50% to 65% for animal waste.   
     
     
         9 . The digester of  claim 1 , wherein:
 the digester achieves 99.999% pathogen kill.   
     
     
         10 . The digester of  claim 1 , wherein:
 the digester is adjustable in order to achieve a SRT/HRT ratio that optimizes the volatile destruction and the corresponding gas production.   
     
     
         11 . The digester of  claim 1 , wherein:
 the digester avoids buildup of heavy organic and inorganic material at the bottom of the vessel via self-cleaning and agitation.   
     
     
         12 . The digester of  claim 1 , wherein:
 each of the components of the agitator adopts an adjustable leading edge to cope with contamination.   
     
     
         13 . The digester of  claim 1 , wherein:
 the agitator turns the material within the plug flow zone into itself by mixing radically away from the central component of the agitator out toward the outer vessel circumference.   
     
     
         14 . The digester of  claim 1 , wherein:
 the agitator has self-cleaning capability and is able to achieve complete, uniform but non-violent homogenization of the vessel contents.   
     
     
         15 . An anaerobic digestion system, comprising:
 a blend tank operable to control and perform pre-treatment of feedstock;   an anaerobic digester operable to digest the feedstock provided from the blend tank in a totally enclosed oxygen-free environment within a specific temperature range;   a bio mass tank operable to process liquid digestate from the anaerobic digester.   
     
     
         16 . The anaerobic digestion system of  claim 15 , wherein:
 the aerobic digestion system operates with a multiplicity of feedstock materials.   
     
     
         17 . The anaerobic digestion system of  claim 15 , wherein:
 the aerobic digestion system draws a specific volume of digestate from the digester and re-circulates it to the blend tank.   
     
     
         18 . The anaerobic digestion system of  claim 17 , further comprising:
 a pH adjust chemical metering pump and/or a pH sensor operable to adjust pH of the feedstock by chemical injection during recirculation.   
     
     
         19 . The anaerobic digestion system of  claim 15 , further comprising:
 an agitator operable to aggressively blend and bring about homogeneity of particle size of the feedstock in the blend tank.   
     
     
         20 . The anaerobic digestion system of  claim 19 , wherein:
 the blend tank and the agitator expedite hydrolysis, acidification and ammonia to ammonium conversion of the feedstock as a multi-functional apparatus.   
     
     
         21 . The anaerobic digestion system of  claim 15 , further comprising:
 a heat exchanger and/or a temperature sensor operable to bring up the feedstock in the blend tank to processing temperatures required in the downstream digester.   
     
     
         22 . The anaerobic digestion system of  claim 15 , wherein:
 the blend tank performs and accomplishes acidification upstream before injecting the feedstock into the digester.   
     
     
         23 . The anaerobic digestion system of  claim 15 , wherein:
 the blend tank converts over  95 % of ammonia to ammonium.   
     
     
         24 . The anaerobic digestion system of  claim 15 , wherein:
 the blend tank breaks down proteins by an enzyme called protease that is secreted by fermentative bacteria.   
     
     
         25 . The anaerobic digestion system of  claim 15 , wherein:
 the blend tank inoculates the pre-treated feedstock with bacteria at pre-treatment stage using anaerobe digestate taken from the discharge of the digester.   
     
     
         26 . The anaerobic digestion system of  claim 15 , wherein:
 the blend tank operates within a percent of total incoming solids.   
     
     
         27 . The digester of  claim 15 , further comprising:
 an inorganics valve operable to remove large inorganic matter from the blend tank during pretreatment.   
     
     
         28 . The anaerobic digestion system of  claim 15 , wherein:
 the feedstock is conditioned in the anaerobic digester to where methanogen is predominant.   
     
     
         29 . The anaerobic digestion system of  claim 15 , wherein:
 the anaerobic digester process organic waste within a temperature range of 35° C. to 70° C. to operate optimally.   
     
     
         30 . The anaerobic digestion system of  claim 15 , wherein:
 water jacket on the underbelly of the anaerobic digester is comprised of multiple zones for temperature management of the digester.   
     
     
         31 . The anaerobic digestion system of  claim 15 , wherein:
 the anaerobic digester utilizes multiple decanting valves for variable decanting in a digestate and capacity specific manner.   
     
     
         32 . The anaerobic digestion system of  claim 15 , further comprising:
 a programmable logic controller (PLC) system operable to optimize and control one or more of in-feed plug flow volume, consistency, temperature, pH, digester operating temperature, decanting, and agitation of the system.   
     
     
         33 . The anaerobic digestion system of  claim 15 , further comprising:
 a water seal tank operable to draw off biogas to maintain an operating pressure within the digester.   
     
     
         34 . The anaerobic digestion system of  claim 15 , further comprising:
 a solids liquid separator operable to separate and process solids and liquids stored in the bio mass tank.