Abstract:
The present invention is a system for producing ethanol and yeast protein feed by fermenting whey permeate, a dairy waste product using four types of tanks: an inoculation tank, a seeding tank, a propagation tank, and a fermentation tank. Whey permeate and various chemicals are added to each of the tanks before being heated. The fermentation process for producing ethanol and yeast protein feed from whey permeate lasts 24 hours.

Description:
FIELD OF INVENTION 
       [0001]    The present invention relates to the field of ethanol production, and more specifically the production of ethanol and yeast protein feed from whey permeate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0002]      FIG. 1  is an exemplary embodiment of an ethanol production system using whey permeate. 
           [0003]      FIG. 2  is an exemplary embodiment of an inoculation tank. 
           [0004]      FIG. 2   a  is an exemplary embodiment of an inoculation tank showi optional components. 
           [0005]      FIG. 3  is an exemplary embodiment of a seeding tank. 
           [0006]      FIG. 3   a  is an exemplary embodiment of a seeding tank showing optional components. 
           [0007]      FIG. 4  is an exemplary embodiment of a propagation tank. 
           [0008]      FIG. 4   a  is an exemplary embodiment of a propagation tank showing optional components 
           [0009]      FIG. 5  in an exemplary embodiment of a fermentation tank. 
           [0010]      FIG. 5   a  in an exemplary embodiment of a fermentation tank showing optional components. 
         TERMS OF ART 
         [0011]    As used herein, “adequate yeast cell count” means approximately 1 million cells per milliliter per tank contents. 
           [0012]    As used herein, “agitator” refers to a tank agitation device for mixing and blending. An agitator may be used for wet and/or dry materials. 
           [0013]    As used herein, the term “air compressor” refers to a device that converts power into kinetic energy by pressurizing and compressing air. 
           [0014]    As used herein, the term “antibiotic” or “anti-microbial” means any anti-microbial agent developed for safe human and animal consumption including chlorine dioxide, hydrogen peroxide, phosphorus, hydrochloric acid, tetracycline, and synthetic antimicrobials effective against pathogenic bacteria resistant to current antimicrobials. 
           [0015]    As used herein, the term “antimicrobial processes” refers to the best practices for inhibiting the growth of bacteria, which includes but is not limited to anti-microbial agents, temperature controlled structure, appropriately set timing devices, processes, and structures to avoid contamination (e.g., CIP practices). 
           [0016]    As used herein, the term “Brix measurement device” means any component capable of measuring Brix levels, including but not limited to a hydrometer, a gas chromatograph (GC), and an HPLC. A Brix level may also be defined as a solids level near-infrared and combinations and equivalents thereof. 
           [0017]    As used herein, the term “ethanol” refers to alcohol that is created by fermentation. 
           [0018]    As used herein, the term “ethanol solution” refers to a solution comprised of any combination of ethanol and water. 
           [0019]    As used herein, the term “fermentation” means the process whereby materials (e.g., lactose sugars) are broken down (e.g., by lactose-fermenting yeast) to create heat and alcohol. 
           [0020]    As used herein, the term “hydrometer” refers to a Brix measuring instrument that measures the specific gravity (or relative density) of liquids; that is, the ratio of the density of the liquid to the density of water. 
           [0021]    As used herein, the term “inoculation” and “inoculant” refers to processes and physical components directed to the introduction of a microorganism (e.g., a strain of yeast) onto a growth medium (e.g., whey permeate). 
           [0022]    As used herein, the term “liquid” includes liquids, viscous solids, and liquids with suspended solids. A liquid may included mixtures into which solids are introduced. 
           [0023]    As used herein, the term “propagation” refers to processes and physical components directed to exponential growth of yeast cultures on whey permeate. 
           [0024]    As used herein, the term “seeding” refers to processes and physical components directed to the initiation of growth of yeast cultures on whey permeate. 
           [0025]    As used herein, the term “separator” refers to a device that separates something into its constituent or distinct elements (e.g., yeast from ethanol water solution). 
           [0026]    A “solid” is a non viscous material, and classifications of liquids and solids may overlap. 
           [0027]    As used herein, the term “Venturi device” means any device known in the art that operates to reduce fluid pressure that results when air or fluid flows through a constricted section of pipe. A Venturi device mechanically incorporates air into the mixture by creating a pumping action by use of a pumping or vacuuming action. A Venturi device may or may not be operatively coupled to a pump and/or use gravity, may be located inside or outside of a tank, or may be used for liquids and solids. It combines the function of three pumps: recirculating, compressor, and transfer. The only pump needed is a circulating pump. 
           [0028]    As used herein, the term “volumetric tank ratio” means the ratio of one tank size to the size of another tank, and may be any constant ratio so long as the yeast cell count is adequately maintained. 
           [0029]    As used herein, the term “whey permeate” refers to a modified dairy product that is obtained by removing protein from whey. 
           [0030]    As used herein, the term “yeast” means any micro-organism capable of converting carbohydrates to carbon dioxide and alcohols. 
         BACKGROUND 
         [0031]    Industrial processes for producing ethanol from whey permeate, a common waste byproduct of cheese production, are desirable because whey permeate is a pollutant, and ethanol can be used for biofuel. Land disposal of surplus whey can endanger the physical and chemical structures of soil, decrease crop yields, and cause serious water pollution. Disposal of surplus whey can be a significant expense because municipalities typically charge businesses for each gallon of their sewage. In addition, surcharges are often incurred for each pound of biochemical oxygen demand, a water pollutant contained in whey permeate. Other water pollutants in whey permeate include chemical oxygen demand, and some municipalities add surcharges for this waste as well. Creating products from whey reduces whey disposal costs for cheese producers, enabling their businesses to become more profitable. Thus, it is desirable to find inexpensive and environmentally-friendly alternatives for cheese producers to create commercially-desirable products from whey. 
           [0032]    Current systems for the fermentation of whey typically require multiple batches, in some cases up to eight batches. Fermentation of each batch requires more than 24 hours. This means that the total fermentation process requires several days to produce biofuel. 
           [0033]    Current methods also typically require multiple steps that increase production cost and time, e.g., monitoring and controlling pH of the whey permeate throughout the process. 
           [0034]    It is desirable for a fermentation process to ferment ethanol from whey permeate in 24 hours using very few steps, because whey permeate can easily spoil or change to a temperature that is not useful for fermentation. 
           [0035]    It is desirable for a system to produce ethanol from whey permeate using whey permeate unloaded from motor vehicles into holding tanks, because this permits fermentation at facilities located away from dairy plants that produce whey permeate as a waste byproduct. 
         SUMMARY OF THE INVENTION 
         [0036]    The present invention is a system for producing ethanol and yeast protein feed by fermenting whey permeate, a dairy waste product. Whey permeate is first pumped into the inoculation tank, and nutrient tubes add various chemicals and antimicrobials. The purpose of the inoculation tank is to introduce a strain of yeast that can ferment whey permeate. The contents of the inoculation tank are heated and transferred to a seeding tank, which initiates the growth of yeast cultures onto whey permeate. Whey permeate and the contents of the inoculation tank are pumped into the seeding tank, and various chemicals and antimicrobials are added by nutrient tubes. The contents of the seeding tank are heated before being transferred to the propagation tank, which exponentially grows yeast cultures on the whey permeate. 
           [0037]    Whey permeate and the contents of the seeding tank are pumped into the propagation tank, and various chemicals and antimicrobials are added by nutrient tubes. The contents of the propagation tank are heated before being transferred to the fermentation tank. Whey permeate and the contents of the propagation tank are pumped into the fermentation tank, and various chemicals and antimicrobials are added by nutrient tubes. The contents of the fermentation tank are heated to ferment whey permeate into ethanol and a yeast protein feed. 
           [0038]    The fermentation process for producing ethanol and yeast protein feed from whey permeate lasts 24 hours. Ethanol is useful as a biofuel, and the yeast protein feed can be used for ruminant animals. The system to produce ethanol from whey permeate can pump the ethanol from the fermentation tank to holding tanks for transport by motor vehicles. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0039]    For the purpose of promoting an understanding of the present invention, references are made in the text to exemplary embodiments of an industrial system producing ethanol from whey permeate, only some of which are described herein. It should be understood that no limitations on the scope of the invention are intended by describing these exemplary embodiments. One of ordinary skill in the art will readily appreciate that alternate but functionally equivalent processes for producing ethanol from whey permeate at an industrial scale may be used. The inclusion of additional elements may be deemed readily apparent and obvious to one of ordinary skill in the art. Specific elements disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to employ the present invention. 
         [0040]    It should be understood that the drawings are not necessarily to scale; instead, emphasis has been placed upon illustrating the principles of the invention. In addition, in the embodiments depicted herein, reference numerals in the various drawings refer to identical or near identical structural elements. 
         [0041]    Moreover, the terms “substantially” or “approximately” as used herein may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. For example, one could make variations to the amounts of corn steep liquor and phosphorus nutrients used. 
         [0042]      FIG. 1  is an exemplary embodiment of an ethanol production system that uses whey permeate  100 . In the exemplary embodiment illustrated by  FIG. 1 , five tanks used to ferment whey permeate are shown; these include inoculation tank  20 , seeding tank  30 , propagation tank  40 , and fermentation tanks  50   a  and  50   b . The first tank used is inoculation tank  20 , the purpose of which is to introduce a strain of yeast that can ferment whey permeate. 
         [0043]    The ratio of the capacity of the tanks is a constant volumetric tank ratio. In the exemplary embodiment shown, inoculation tank  20  has an inner chamber possessing a capacity of 60 gallons. Seeding tank  30  has an inner chamber possessing a capacity of 600 gallons (or ten times the capacity of inoculation  20 ). Propagation tank  40  has an inner chamber possessing a capacity of 6,000 gallons (or ten times the capacity of inoculation  30 ). In the exemplary embodiment shown, fermentation tanks  50   a  and  50   b  each have an inner chamber possessing a capacity of 30,000 gallons, instead of a single 60,000 gallon fermentation tank, thus spotting the necessary volume (based on the propagation tank volume) into two tanks. When fermentation occurs in two tanks, the air flow (aeration) is optimized in this exemplary embodiment. Other embodiments may use more or fewer tanks. 
         [0044]    Inoculation tank  20 , seeding tank  30 , and propagation tank  40  may be spot into smaller tanks so long as the volumetric tank ratio is preserved, and/or so long as the adequate yeast cell count is maintained. 
         [0045]    In the exemplary embodiment shown in  FIG. 2 , inoculation tank  20  is the first step tank into which materials are introduced during fermentation process. Inoculation tank  20  has an inner chamber with a capacity of 60 gallons. In further exemplary embodiments, inoculation tank  20  may have a capacity larger or smaller than 60 gallons. In further exemplary embodiments, additional inoculation tanks may be used. 
         [0046]    As shown in  FIG. 2 , pipe  21   a  unloads whey permeate from a truck in deposits of 55 gallons, 11 to 12 percent of which is solid, into inoculation tank  20 . Pipe  21   b  conducts the whey permeate from unloading pump  27  to inoculation tank  20 . In the embodiment shown, unloading pump  27  is a centrifugal pump known in the art. In further exemplary embodiments, deposits of more or fewer gallons may be used. 
         [0047]    As shown in  FIG. 2 , Venturi pipe  94  is a Venturi device with constricted section  94   a  that produces a Venturi effect. Constricted section  94   a  has a circumference of three quarters of an inch, and the tubular body of Venturi pipe  94  has a circumference of 2-4 inches. Tubular diameter dimensions will increase as tank size increases. The embodiment shown includes vertical air feed tube  93  that transfers air into inoculation tank  20 . 
         [0048]    A Venturi device mechanically incorporates air into the mixture by creating a pumping action by use of a pumping or vacuuming action. In the exemplary embodiment shown, Venturi pipe  94  may or may not be operatively coupled to a Venturi pump  95  and/or use gravity to induce flow. A Venturi device may be located inside or outside of a tank and may be used for liquids and solids. 
         [0049]      FIG. 2  further illustrates nutrient tubes  72   a ,  72   b , and  72   c  to convey nutrients into inoculation tank  20 . Nutrient tube  72   a  conveys nitrogen (e.g., urea ammonium nitrate), nutrient tube  72   b  conveys phosphorus (e.g., liquid ammonium phosphate), and nutrient tube  72   c  conveys corn steep liquor. In the embodiment shown, these nutrients are commercially available. 
         [0050]    The contents of inoculation tank  20  are then brought to the approximate temperature of 85 degrees by heat exchanger assembly  92 , which is commercially available and known in the art. In the embodiment shown, heat exchanger assembly  92  includes a temperature measuring component, heating components, and a cleaning component. Once the proper temperature has been reached, a quantity of a strain of yeast (e.g.,  Kluyveromyces marxianus ) is manually introduced into inoculation tank  20  at a ratio of 1 gallon per 60 gallons. Further exemplary embodiments may use different quantities of  Kluyveromyces marxianus  or different strains of yeast culture. 
         [0051]    Antimicrobial port  33  is a port for introducing antimicrobials into inoculation tank  20 . Port  34  is for adding an actual inoculant. In various embodiments, both may be added through the same or different ports, and in still other embodiments, ports  33  and  34  could be a tube or other receptacle. Further embodiments need not require anti-microbial agents if microbial levels are minimal. 
         [0052]    The contents of inoculation tank  20  are then checked for the liquid to solid ratio and Brix level with sugar hydrometer  2 , which is a Brix measurement device. In this exemplary embodiment, this first occurs after eight hours and at every four hours thereafter. At the correct time, the contents of inoculation tank  20  are transferred to seeding tank  30  by transfer pump  29  through discharge tube outlet  82 . 
         [0053]      FIG. 2   a  illustrates an alternative exemplary embodiment of inoculation tank  20  that demonstrates optional components that can be added to inoculation tank  20  illustrated in  FIG. 2  if needed. 
         [0054]    Air compressor  12  supplies additional air if the air provided by Venturi device  94  is inadequate. In further embodiments, a blower may be used instead of air compressor  12 . 
         [0055]    Agitator  62   b  with agitator motor  62   a  stirs the contents of inoculation tank  20 . 
         [0056]    Thermal tank jacket  22  can be added around inoculation tank  20  in place of heat exchanger  92  (not shown). 
         [0057]    In the exemplary embodiment shown in  FIG. 3 , seeding tank  30  is the second step tank into which materials are introduced during the fermentation process. Seeding tank  30  has an inner chamber with a capacity of 600 gallons. In further exemplary embodiments, seeding tank  30  may have a capacity larger or smaller than 600 gallons. In further exemplary embodiments, additional seeding tanks may be used. As shown in  FIG. 3 , seeding tank  30  receives the contents of inoculation tank  20  (not shown) through discharge tube outlet  82 . 
         [0058]    As shown in  FIG. 3 , Venturi pipe  64  is a Venturi device with constricted section  64   a  that produces a Venturi effect. Tubular diameter dimensions of Venturi pipe  64  and constricted section  64   a  will vary depending on the size of seeding tank  30 . The embodiment shown includes vertical air feed tube  63  that transfers air into seeding tank  30 . 
         [0059]    In the exemplary embodiment shown, Venturi pipe  64  may or may not be operatively coupled to a Venturi pump  65  and/or use gravity to induce flow. A Venturi device may be located inside or outside of a tank and may be used for liquids and solids. 
         [0060]      FIG. 3  further illustrates nutrient tubes  73   a ,  73   b , and  73   c  to convey nutrients into seeding tank  30 . Nutrient tube  73   a  conveys nitrogen (e.g., urea ammonium nitrate), nutrient tube  73   b  conveys phosphorus (e.g., liquid ammonium phosphate), and nutrient tube  73   c  conveys corn steep liquor. In the embodiment shown, these nutrients are commercially available. 
         [0061]    In the exemplary embodiment shown in  FIG. 3 , one ounce of antimicrobial feed and one quarter gallon of hydrogen peroxide are fed into seeding tank  30 . Further exemplary embodiments may use different amounts of antimicrobial feed or hydrogen peroxide, depending on the amount of whey permeate that is used. Still further embodiments may use a different antimicrobial feed. In other exemplary embodiments, different amounts of antimicrobials and hydrogen peroxide may be used depending on the amount of the other nutrients used. Further embodiments need not require anti-microbial agents if microbial levels are minimal. 
         [0062]    The contents of seeding tank  30  are then brought to the approximate temperature of 88 degrees by heat exchanger assembly  96 , which is commercially available and known in the art. In the embodiment shown, heat exchanger assembly  96  includes a temperature measuring component, heating components, and a cleaning component. 
         [0063]    The contents of seeding tank  30  are then checked for the liquid to solid ratio and Brix level with sugar hydrometer  3 , which is a Brix measurement device. At the correct time, the contents of seeding tank  30  are transferred to propagation tank  40  by transfer pump  39  through discharge tube outlet  83 . 
         [0064]      FIG. 3   a  illustrates an alternative exemplary embodiment of seeding tank  30  that demonstrates optional components that can be added to seeding tank  30  illustrated in  FIG. 3  if needed. 
         [0065]    Air compressor  13  supplies additional air if the air provided by Venturi device  64  is inadequate. In further embodiments, a blower may be used instead of air compressor  13 . 
         [0066]    Agitator  61   b  with agitator motor  61   a  stirs the contents of seeding tank  30 . 
         [0067]    Thermal tank jacket  32  can be added around seeding tank  30  replacing heat exchanger  96  (not shown). 
         [0068]    In the exemplary embodiment shown in  FIG. 4 , propagation tank  40  is the third step tank into which materials are introduced during the fermentation process. Propagation tank  40  has an inner chamber with a capacity of 6,000 gallons. In further exemplary embodiments, propagation tank  40  may have a capacity larger or smaller than 6,000 gallons. In further exemplary embodiments, additional propagation tanks may be used. 
         [0069]    Propagation tank  40  receives the contents of seeding tank  30  (not shown) through discharge tube outlet  83 . 
         [0070]    As shown in  FIG. 4 , Venturi pipe  24  is a Venturi device with constricted section  24   a  that produces a Venturi effect. Tubular diameter dimensions of Venturi pipe  24  and constricted section  24   a  will vary depending on the size of propagation tank  40 . The embodiment shown includes vertical air feed tube  23  that transfers air into propagation tank  40 . 
         [0071]    In the exemplary embodiment shown, Venturi pipe  24  may or may not be operatively coupled to a Venturi pump  25  and/or use gravity to induce flow. A Venturi device may be located inside or outside of a tank and may be used for liquids and solids. 
         [0072]      FIG. 4  further illustrates nutrient tubes  74   a ,  74   b , and  74   c  to convey nutrients into propagation tank  40 . Nutrient tube  74   a  conveys nitrogen (e.g., urea ammonium nitrate), nutrient tube  74   b  conveys phosphorus (e.g., liquid ammonium phosphate), and nutrient tube  74   c  conveys corn steep liquor. In the embodiment shown, these nutrients are commercially available. 
         [0073]    In the exemplary embodiment shown in  FIG. 4 , two ounces of antimicrobial feed and one quarter gallon of hydrogen peroxide are fed into propagation tank  40 . Further exemplary embodiments may use different amounts of antimicrobial feed or hydrogen peroxide, depending on the amount of whey permeate that is used. Still further embodiments may use a different antimicrobial feed. In other exemplary embodiments, different amounts of antimicrobials and hydrogen peroxide may be used depending on the amount of the other nutrients used. Further embodiments need not require anti-microbial agents if microbial levels are minimal. 
         [0074]    The contents of propagation tank  40  are then brought to the approximate temperature of 90-91 degrees by heat exchanger assembly  46 , which is commercially available and known in the art. In the embodiment shown, heat exchanger assembly  46  includes a temperature measuring component, heating components, and a cleaning component. 
         [0075]    The contents of propagation tank  40  are then checked for the liquid to solid ratio and Brix level with sugar hydrometer  4 , which is a Brix measurement device. At the correct time, the contents of propagation tank  40  are transferred to fermentation tank  50  by transfer pump  49  through discharge tube outlet  84 . 
         [0076]      FIG. 4   a  illustrates an alternative exemplary embodiment of propagation tank  40  that demonstrates optional components that can be added to the inoculation tank  40  illustrated in  FIG. 4  if needed. 
         [0077]    Air compressor  14  supplies additional air if the air provided by Venturi device  24  is inadequate. In further embodiments, a blower may be used instead of air compressor  14 . 
         [0078]    Agitator  98   b  with agitator motor  98   a  stirs the contents of propagation tank  40 . 
         [0079]    Thermal tank jacket  42  can be added around propagation rank  40  replacing heat exchanger  46  (not shown). 
         [0080]    In the exemplary embodiment shown in  FIG. 5 , fermentation tank  50  is the fourth and final step tank into which materials are introduced during the fermentation process. Fermentation tank  50  has an inner chamber with a capacity of 30,000 gallons. In further exemplary embodiments, fermentation tank  50  may have a capacity larger or smaller than 30,000 gallons, depending on the desired production level for ethanol and yeast protein feed. In further exemplary embodiments, additional fermentation tanks may be used. As shown in  FIG. 5 , Fermentation tank  50  receives the contents of propagation tank  40  (not shown) through discharge tube outlet  84 . 
         [0081]    As shown in  FIG. 5 , Venturi pipe  44  is a pipe with constricted section  44   a  that produces a Venturi effect. Tubular diameter dimensions of Venturi pipe  44  and constricted section  44   a  will vary depending on the size of fermentation tank  50 . The embodiment shown includes vertical air feed tube  53  that transfer air into fermentation tank  50 . 
         [0082]    In the exemplary embodiment shown, Venturi pipe  44  may or may not be operatively coupled to a Venturi pump  45  and/or use gravity to induce flow. A Venturi device may be located inside or outside of a tank and may be used for liquids and solids. 
         [0083]      FIG. 5  further illustrates nutrient tubes  75   a ,  75   b , and  75   c  that convey nutrients into fermentation tank  50 . Nutrient tube  75   a  conveys nitrogen (e.g., urea ammonium nitrate), nutrient tube  75   b  conveys phosphorus (e.g., liquid ammonium phosphate), and nutrient tube  75   c  conveys corn steep liquor. In the embodiment shown, these nutrients are commercially available. 
         [0084]    In the embodiment shown in  FIG. 5 , five ounces of antimicrobial feed are fed into fermentation tank  50 . Further exemplary embodiments may use different amounts of antimicrobial feed or hydrogen peroxide, depending on the amount of whey permeate that is used. Still further embodiments may use a different antimicrobial feed. In other exemplary embodiments, different amounts of antimicrobials and hydrogen peroxide may be used depending on the amount of other nutrients used. Further embodiments need not require anti-microbial agents if microbial levels are minimal. 
         [0085]    The contents of fermentation tank  50  are then brought to the approximate temperature of 95-98 degrees by heat exchanger assembly  29 , which is commercially available and known in the art. In the embodiment shown, heat exchanger assembly  29  includes a temperature measuring component, heating components, and a cleaning component. 
         [0086]    The contents of fermentation tank  50  are then checked for the liquid to solid ratio and Brix level with sugar hydrometer  5 , which is a Brix measurement device. At the correct time, the contents of fermentation tank  50  are transferred to separator  10  to by transfer pump  59  through discharge tube outlet  85 . In separator  10 , ethynol is separated from yeast protein. The ethanol is then pumped through collection pipe  99  into holding tanks (not shown). 
         [0087]      FIG. 5   a  illustrates an alternative exemplary embodiment of fermentation tank  50  that demonstrates optional components that can be added to fermentation tank  50  illustrated in  FIG. 5  if needed. 
         [0088]    Air compressor  15  supplies additional air if the air provided by Venturi device  44  is inadequate. In further embodiments, a blower may be used instead of air compressor  15 . 
         [0089]    Agitator  97   b  with agitator motor  97   a  stirs the contents of fermentation tank  50 . 
         [0090]    Thermal tank jacket  52  can be added around fermentation tank  50  replacing heat exchanger  29  (not shown).