Anaerobic Digester System

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<ul><li><p>US006296766B1 </p><p>United States Patent (12) (10) Patent N0.: US 6,296,766 B1 Breckenridge (45) Date of Patent: Oct. 2, 2001 </p><p>(54) ANAEROBIC DIGESTER SYSTEM 5,500,118 3/1996 Coenen et a1. ..................... .. 210/603 5,500,123 3/1996 Srivastava .. 210/603 </p><p>(76) Inventor: Leon Breckenridge, 16213 E. 22nd, 5,500,306 3/1996 H511 6t a1~ 429/ 17 Veradale, WA (Us) 99037 5,525,228 6/1996 Da'gue et al 210/603 </p><p>5,525,229 6/1996 s1nn ........... .. 210/603 </p><p>( * ) Notice: Subject to any disclaimer, the term of this gig: et a1 """"""""""" " gtsenct lisiinkisi) cgyaslusted under 35 5,547,578 * 8/1996 Nielsen .............................. .. 210/614 ' ' ' ' 5,581,459 * 12/1996 Enbutsu et 81.. </p><p>5,589,068 * 12/1996 Nielsen .............................. .. 210/614 (21) Appl. N0.: 09/439 815 5,597,399 1/1997 Basu et a1. ....... .. 71/9 </p><p>_ 5,601,720 * 2/1997 Schmid ...... .. 210/614 (22) Flledz Nov. 12, 1999 5,637,219 6/1997 Robinson 6161. .. 210/603 </p><p>7 5,774,633 * 6/1998 Baba et al.. .............................. 578067903 * 3/1999 LO _ </p><p>. . . ............................ .. 510/614; 706/903, * Cited by examiner </p><p>(58) Field Of Search .................................. .. 210/96.1, 143, Primary Examiner_JOSeph 7V~ Dredge 210/603&gt; 614 739 601 610 613 615; (74) Attorney, Agent, or FirmStratton BalleW PLLC 435/267, 286.1, 289.1; 71/7, 8, 10, 11, </p><p>13, 9; 706/15, 903, 914, 932 (57) ABSTRACT (56) References Cited A method for an anaerobic digester system is provided that </p><p>employs a cumulative data base to better momtor and US. PATENT DOCUMENTS control the anaerobic process, as compared With conven </p><p>3933628 1/1976 Varani _ tional anagrobie1 digesfterfsyiitemsk The fmetbhlod igeludes the 4,100,023 7/1978 McDonald _ storing an ens1 mg 0 a ee~ stoc ,pre era y a 1omass, to 4,161,426 7/1979 Kneer_ form a digester feed material, vvhich then processed by a 4,437,987 3/1984 Thornton et a1_ __ _ 210/137 digester. The process evolves a biogas and forms a digested 4,613,433 9/1986 McKeoWn .... .. . 210/150 material. The process is monitored, to collect a plurality of 4,648,968 3/ 1987 Cutler ---- -- - 210/218 digester data from all stages of the process. These individual 4,710,292 12/1987 DeV95 ~~ - 210/218 points or elements of the data are telemetered to a cumula 5O8O786 1/1992 De Luna 1 ' 210/218 tive data base for storage and eventual retrieval and the </p><p>gloifwskl " cumulative data base is mined to compile predictive, feed e um """""""""""""""""" " forward controls and construct feedstock correlations </p><p>5,185,079 2/1993 Dague ................................ .. 210/603 b h b 1. . . . h. h d. d 572077911 5/1993 pellegrin et aL _ 21O/6O3 etWeen t e meta 0 10 activity Wit m't e igesters an an 572277051 7/1993 Oshima _____ __ _ 210/137 analysis of the feedstocks mto the digesters. The method 5,240,611 8/1993 _21()/603 further includes the production of a high quality plant 5,248,423 * 9/1993 . 210/614 roWth media from the di ested mash, and recover of the g g Y 5,282,879 2/1994 Baccarani - - - - - - - - - - -- 71/10 biogas generated Within the digester. The biogas is collected 5,310,485 5/1994 Roshanravan ...................... .. 210/603 the of a biogas recovery system_ The biogas is </p><p>et al' """"""""""""" " predominantly methane, and the anaerobic digester system 0, mson is preferably operated to maXimiZe the quantity and quality </p><p>211511313 31133? nvo?ityflnill. ...'."213 of methane generated 5,470,745 * 11/1995 Beteau et al. .. . 435/286.1 5,490,933 2/1996 LaPack et al. ..................... .. 210/603 9 Claims, 7 Drawing Sheets </p><p>i, F , tn ShovHcrmStoragTe7T\ </p><p>Renews 1 Pm Weigh CDSSl?g </p><p>Senaraie </p><p>Storage 2. </p><p>Packagmg </p><p>DIGESTER SYSTEM </p><p>(Trench Silos) 4&gt; m </p><p>Long term Storage </p><p>2a,, , W </p><p>Gas lo " \ Process 1 </p><p>5 </p><p>\ 0 </p><p>Gas 5 1 Blower 1 </p><p>\i </p></li><li><p>U.S. Patent 0a. 2, 2001 Sheet 4 0f 7 US 6,296,766 B1 </p><p>65665.8 8 =66: 3562a : mm </p><p>mm </p><p>H .6265 $0 </p><p>332m 8 $0 </p><p>65:00 a 223 5 </p><p>mm </p><p>8 v2.5 </p></li><li><p>U.S. Patent 061. 2, 2001 Sheet 6 6f 7 US 6,296,766 B1 </p><p>mm EPEEQE .650 mn :E 5:25.: $ t5 </p><p>wk mum $0 .65: </p><p>E mum mcmutzmmoi </p></li><li><p>US 6,296,766 B1 1 </p><p>ANAEROBIC DIGESTER SYSTEM </p><p>TECHNICAL FIELD </p><p>The invention relates to a digester system that utilizes anaerobic microbes to convert organic material into a biogas and a plant groWth media on an industrial scale. More speci?cally, the present invention relates to a process for monitoring, then analyzing and ?nally, very precisely con trolling a multistage digestion process, to optimize operation of the digester system. The process includes an anaerobic digester, and a control system for the digester that employs pattern recognition. </p><p>BACKGROUND OF THE INVENTION </p><p>The pre-treatment of cattle feed or roughage, before feeding it to cattle, has long been a subject of research. For instance, during the drought years of the 1930s, there Was a need to make cattle feed out of Weeds and about anything else that Was groWing. It Was then demonstrated that almost any organic material having any potential as fodder could be made into digestible animal feed. The green fodder could be preserved and converted into animal feed Within a silo or similar storage. The process of storing and preserving fodder is knoWn as ensiling. </p><p>Ensilage is essentially a partially fermented organic mate rial. Most temperate regions of the planet generate large amounts of organic material, commonly called biomass. Most biomass is considered a Waste material and typically disposed of as rubbish. Much of this Waste material could be converted into a plant groWth media and methane (CH4) by ?rst converting it to silage and then processing it through an anaerobic methane producing digester. </p><p>The anaerobic digestion process can be fed by an enor mous variety of biomass sources. As a result, the process can be used to resolve an equally Wide variety of Waste disposal problems. If this Waste biomass can be ef?ciently converted into energy, it could be utilized to replace scarce fossil fuels. Some site speci?c sources of biomass include: </p><p>Dairy farms Fruit processors Mint farms Cheese plants Potato processors Hog farms Cattle feed lots Egg farms Poultry farms Hop farms Frozen food </p><p>processors </p><p>Some examples of particular biomass materials include: </p><p>Wheat straW Corn silage Rice StraW Food Wastes Grass seed straW Residential yard Selected municipal </p><p>debris solid Wastes </p><p>The physical aspects of an anaerobic digester system are essentially a vessel and all of the necessary accessories and other components to create an environment as close as possible to that in Which the anaerobe microorganisms naturally live. The initial digestive chambers of bovines are excellent examples of a Well functioning anaerobic digester found in nature. The ingestion of grasses or other similar materials by the bovine ultimately produces a manure mash, Which is an excellent fertilizer, and produces a methane gas (CH4) emission, as a by-product. </p><p>Operating an ef?cient anaerobic digester roughly pat terned after naturally occurring digestive systems, but at an </p><p>10 </p><p>15 </p><p>25 </p><p>35 </p><p>45 </p><p>55 </p><p>65 </p><p>2 industrial scale, is not a simple task. The feedstocks for such industrial processes are substantially composed of biologi cally generated material. A lack of uniform quality of the end product is almost </p><p>universal in most, if not all, existing industrial scaled anaerobic digesters, and composting operations of a signi? cant scale. This lack in uniformity has led to the dismissal of anaerobic digestion as a viable, reliable methane industrial scale source of methane. To operate even a simple anaerobic digester that substantially mimics the biomass digestive systems found in nature, poWerful and sensitive system monitoring methods and controls are needed. This is because in the natural bovine system, hundreds of thousands or even millions of minute and symbiotic organisms have evolved over eons to a self-regulating system. </p><p>In the industrial setting, We can observe an example of a high level of sensitivity in the precision of an industrial fermentation process, as typically performed to produce a top quality beer. Typical industrial process control systems use at least one physical parameter, such as pressure, time or temperature for a primary control. When closer control is needed, a second physical parameter is used. Occasionally, a third parameter may also be employed. The use of this third parameter or 3rd level of control usually results in a process control system With much higher precision than that processs ability to be accurately controlled. </p><p>Currently, in most industrial scale anaerobic digesters, the design of various components of the digesters coupled With the control system together alloW the temperature to ?uc tuate anyWhere from plus or minus tWo or three degrees Fahrenheit up to occasional variations having a range often degrees F., or more. For the digesters anaerobes, even a single degree F change in temperature is at least one hundred times greater than the phenomena that needs to be measured, Which is the heat generated by the anaerobes. Therefore, for these conventional industrial digesters, the ten degree dead band or noise level of the signal from the phenomena to be measured or controlled, is ten to one hundred times larger than the phenomenas metabolic heat signal that needs to be accurately measured. A precision control system is of no bene?t for these </p><p>conventional, industrial anaerobic digester systems, because the physical design of the anaerobic digester does not permit ?ne tuning due to the errors produced by the measurement and control system. Therefore, a need exists for both a digester design and a control system for an industrial anaero bic digester, Which are better able to monitor and control the anaerobic process. </p><p>SUMMARY OF INVENTION </p><p>The present invention provides a method for an anaerobic digester system. The method speci?cally addresses the con trol difficulties of industrial scale anaerobic digesters, and solves these dif?culties by employing a cumulative data base to better monitor and control the anaerobic process, as compared With conventional anaerobic digester systems. The method of the present invention includes the storing </p><p>of a feedstock, preferably a biomass, to form a digester feed material. This digester feed material is processed by a digestion process, Which mimics the bovine digestion process, in a digester. The process evolves a biogas and forms a digested material. Importantly, the process is monitored, to collect a plurality of digester datum from the digester, and preferably from all stages of the process. These individual points or elements of the datum are telemetered to a cumulative data base for storage and eventual retrieval. </p></li><li><p>US 6,296,766 B1 3 </p><p>The cumulative data base is mined to compile a predictive, feed forward control of an anaerobic digester system. The term mining is employed to describe the process of utilizing an arti?cially intelligent softWare application to draW speci?c relationships from the cumulative data base. This data mining softWare is a prepackaged and commer cially available product, yet highly adaptable to user speci?c applications. In the present invention, the results of the data mining can be used to construct feedstock correlations betWeen the metabolic activity Within the digesters and an analysis of the feedstocks into the digesters. These feedstock correlations can be employed in both feed back and feed forWard controls of the anaerobic digester system. </p><p>The method of the present invention can further include a recovery of the biogas generated Within the digester, With the aid of a biogas recovery system. With the typical biomass feedstock, the biogas formed Within the digester is predomi nantly methane, and the anaerobic digester system is pref erably operated to maXimiZe the quantity and quality of methane generated. This biogas formation can be directly related to the metabolic activity Within the digesters and optimiZed With the correlations discovered in the mining of the cumulative data base. </p><p>The invention Will be better understood by reference to the folloWing detailed description taken in conjunction With the accompanying draWings. </p><p>BRIEF DESCRIPTION OF DRAWINGS </p><p>FIG. 1 is a schematic illustration of an overvieW of an embodiment of the present invention; </p><p>FIG. 2 is a schematic illustration of a receiving, pretreat, storage and control portion of an embodiment of the present invention, </p><p>FIG. 3 is a schematic illustration of a formulating, miXing and control portion of an embodiment of the present inven tion; </p><p>FIG. 4 is a schematic illustration of a digester and control portion of an embodiment of the present invention; </p><p>FIG. 5 is a schematic illustration of a SCADA portion of an embodiment of the present invention; </p><p>FIG. 6 is a schematic illustration of a digester cross section of an embodiment of the present invention; and </p><p>FIG. 7 is a schematic illustration of a digester system pattern recognition portion of an embodiment of the present invention. </p><p>DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS </p><p>The invention provides a method for a digester system that utiliZes anaerobic microbes to convert organic material into methane (CH4) and a plant groWth media on an indus trial scale. System OvervieW A preferred embodiment of a digester system of the </p><p>present invention is schematically shoWn in FIGS. 1 through 7. FIG. 1 shoWs an overvieW of the digester system 10. The pre-treatment processing stage of the digester system receives and processes a solid feedstock 12. The pre treatment process used by the digester system is the process called ensilaging, or making silage. Ensilaging is a ?rst phase of the anaerobic digestion process in Which a biomass, or solid feedstock is prepared for a digester 35 by an initial, acidic fermentation by anaerobic microorganisms. The solid feedstock is received into preprocessing and storage com ponents 13. The digester system initially transfers a pre </p><p>10 </p><p>15 </p><p>25 </p><p>35 </p><p>45 </p><p>55 </p><p>65 </p><p>4 processed material stream 20 into a storage component 22, Which, as detailed in FIG. 2, are preferably a parallel set of trench silos, or a long term storage 22B. The pre-processed material stream 20 is ensilaged in the </p><p>trench silos. The process of making and storing of the solid feedstock 12 as a silage also alloWs the material to be analyZed as a food source for the anaerobes that are currently active Within the digesters 35. For a sustainable anaerobic digestion, there are typically more than tWenty varieties of anaerobes active at any one time. These microbes can quickly mutate and adapt to ?ourish in neW environmental conditions Within a feW days. As shoWn in FIG. 1, an ensilaged material stream 25, from </p><p>the storage 22 is selectively fed into one of the metering bins 30, Which are preferably positioned in parallel as shoWn in FIG. 3. The metering bins measure speci?c quantities of the ensilaged material to form a digester feed material stream 31. The digester feed material is then introduced into a miXer 32. The dige...</p></li></ul>

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