U.S. patent application number 14/324796 was filed with the patent office on 2014-10-30 for method and apparatus for bio-fuel seeding.
The applicant listed for this patent is TOMMY MACK DAVIS. Invention is credited to TOMMY MACK DAVIS.
Application Number | 20140322782 14/324796 |
Document ID | / |
Family ID | 41696732 |
Filed Date | 2014-10-30 |
United States Patent
Application |
20140322782 |
Kind Code |
A1 |
DAVIS; TOMMY MACK |
October 30, 2014 |
METHOD AND APPARATUS FOR BIO-FUEL SEEDING
Abstract
A method and apparatus is provided for microbial seeding and
amendment of traditional alternative fuels production systems and
processes using immobilized microbe bioreactors. The system
addition utilizes attachment of yeast or other microbial consortia
to a substrate to enhance alternative fuels production in
fermentation processes. The system allows for the maintenance of a
constant concentrated microbial population, thus enhancing
alternative fuels production by stabilizing microbial populations.
Desired aerobic and anaerobic conditions are maintained using a
microbubble aeration device coupled to the Immobilized Microbe
Bioreactor (IMBR) seeding reactors. Generation of the microbial
populations for seeding requires control of aerobic and anaerobic
conditions to ensure growth of a microbial population acclimated to
elevated alternative fuels concentrations.
Inventors: |
DAVIS; TOMMY MACK;
(SPARTANBURG, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DAVIS; TOMMY MACK |
SPARTANBURG |
SC |
US |
|
|
Family ID: |
41696732 |
Appl. No.: |
14/324796 |
Filed: |
July 7, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13555538 |
Jul 23, 2012 |
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14324796 |
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12462086 |
Jul 29, 2009 |
8227219 |
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13555538 |
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Current U.S.
Class: |
435/161 |
Current CPC
Class: |
Y02E 50/17 20130101;
Y02E 50/10 20130101; C12P 7/06 20130101 |
Class at
Publication: |
435/161 |
International
Class: |
C12P 7/06 20060101
C12P007/06 |
Claims
1. A method of producing ethanol comprising: a. supplying feed
stock into a first container, wherein said feed stock contains at
least one type of sugar; b. measuring the sugar concentration of
said feed stock; c. adjusting said sugar concentration of said feed
stock to fall within a predetermined range; d. introducing said
feed stock from said first container into at least one bio-reactor,
wherein said at least one bio-reactor comprises: (i) a second
container; (ii) at least one substrate disposed within said second
container, wherein said at least one substrate is inoculated with
at least one microbial population, preselected for fermentation
capability, and said at least one microbial population propagates
on the surface of said at least one substrate; e. adding gas to
said bio-reactor using at least one micro bubble generator; f.
fermenting said feed stock within said bio-reactor under
substantially anaerobic conditions to generate ethanol; g.
capturing gas vented from said at least one bio-reactor; and h.
delivering said gas to an inlet of said at least one micro bubble
generator.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] THIS APPLICATION IS A CONTINUATION OF U.S. patent
application Ser. No. 13/555,538, FILED Jul. 23, 2012, CURRENTLY
PENDING, WHICH IS A CONTINUATION OF U.S. patent application Ser.
No. 12/462,086, FILED Jul. 29, 2009, NOW ISSUED AS U.S. Pat. No.
8,227,219.
STATEMENTS AS TO THE RIGHTS TO THE INVENTION MADE UNDER FEDERALLY
SPONSORED RESEARCH AND DEVELOPMENT
[0002] NONE
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention pertains to a method and apparatus for
the production of bio-fuels and related compounds including, but
not limited to, ethanol. More particularly, the present invention
pertains to a microbial seeding system that can be used in the
production of bio-fuels, either as a stand-alone process or as part
of an existing fermentation system.
[0005] 2. Brief Description of the Prior Art
[0006] As demand for fossil fuel increases, and supply decreases,
the costs associated with such fossil fuels can be significant.
Additionally, many believe that consumption of fossil fuels
negatively impacts the environment by contributing to global
warming. Thus, an effort has been underway to find alternative
energy sources that can act as a replacement for conventional
fossil fuels.
[0007] Much attention has focused on bio-fuels as a possible
alternative to fossil fuels. Generally, bio-fuels are solid, liquid
or gaseous fuels obtained from relatively recently lifeless or
living biological material. By contrast, fossil fuels are derived
from long-dead biological material. One such bio-fuel that has
received a great deal of attention is ethanol, a primarily
plant-based fuel which can be produced from organic sources such as
sugar cane, corn, waste paper. Ethanol can also be produced from
grains like wheat or sorghum.
[0008] Ethanol, also known as ethyl alcohol, is a volatile,
flammable, colorless liquid having a wide variety of uses
including, but not limited to, as a fuel. For example, ethanol has
a long history as a fuel for heat and light, and also as a fuel
and/or fuel additive for internal combustion engines. When added to
gasoline, ethanol reduces volatile organic compound and hydrocarbon
emissions, carcinogenic benzene and butadiene emissions, and
particulate matter emissions from internal combustion engines.
Ethanol is also widely used as a solvent of substances intended for
human contact or consumption. In chemistry, ethanol is both an
essential solvent and a feedstock for the synthesis of other
products, as well as a fuel to power direct-ethanol fuel cells
(DEFC) in order to produce electricity.
[0009] Although ethanol can be produced via the hydration of
ethylene, it is commonly produced biologically through the process
of culturing yeast under certain desired conditions (this process
is commonly referred to as fermentation). When certain species of
yeast (for example, Saccharomyces cerevisiae) metabolize sugar, the
yeast can produce ethanol and carbon dioxide. Ethanol can also be
produced biologically from starchy materials such as cereal grains;
however, in such cases, the starchy material must first be
converted into sugar(s).
[0010] Feed stocks for the production of ethanol can include, but
are not limited to, sugarcane juice, sugarcane syrup, molasses,
bagasse, corn, fruit juice and concentrates, purified sugars such
as sucrose, glucose, fructose, maltose, and syrup mixtures
containing simple sugars such as those found in drink syrups.
[0011] Existing processes for the production of ethanol have proven
to be inefficient and expensive, and frequently require a large
amount of space. Thus, there is a need for a seeding process that
can be used to improve overall efficiency, while reducing costs and
space requirements, associated with conventional ethanol production
processes.
SUMMARY OF THE PRESENT INVENTION
[0012] In the preferred embodiment, the seeding system of the
present invention generally comprises: [0013] at least one
pre-fermentation nutrient amendment/antibiotic tank and pump;
[0014] make-up water supply lines for feedstock concentration
control; [0015] at least one pre-fermentation mixing/holding tank;
[0016] at least one immobilized microbe bioreactor ("IMBR"); and
[0017] at least one surge tank for consistent flow of seeding
material to secondary fermentation tanks.
[0018] In the preferred embodiment, the present invention
beneficially comprises at least one IMBR cluster having a plurality
of IMBR microbial generation reactors, beneficially including
oxygen source(s) for periodic oxygenation of such generation
reactors. Such oxygen can be introduced as air pumped via
conventional fans or air blowers, or as pure oxygen. It is to be
observed that the seeding system of the present invention can
function as a stand-alone system, or can be incorporated within a
traditional fermentation process and system.
[0019] In the preferred embodiment, microbial generation and
seeding is accomplished using IMBR technology in which microbes are
immobilized on a desired substrate. Such IMBR technology
beneficially utilizes at least one bio-carrier medium inoculated
with desired microbes; said at least one bio-carrier medium can
include, without limitation, porous diatomaceous earth solids (such
as described in U.S. Pat. No. 4,859,594 and U.S. Pat. No.
4,775,650, which are incorporated herein by reference). In the
preferred embodiment, said at least one bio-carrier medium is
beneficially coated with a thin film of chitin or other substance,
and yeast cells or other beneficial microbes are immobilized on the
surfaces of such at least one bio-carrier medium. Further, in the
preferred embodiment, at least one micro bubble generator (MBG)
immobilized cell reactor (for example, the MBG more fully disclosed
in U.S. Pat. No. 5,534,143, which is incorporated herein by
reference) is provided for periodic aeration and nutrient addition
to a liquid column with bottom-up flow.
[0020] By promoting in-situ growth of desired yeast and/or other
microbial populations, the present invention promotes microbial
growth and acclimation within the fermentation tanks, piping and
associated elements of the present invention. Over time, the
microbial growth provided by the present invention can result in
the spread of yeast and/or other beneficial microbial agents
throughout the system, thereby improving the fermentation process
and overall system efficiency.
[0021] Varying feed stocks can be used for fermentation including,
but not limited to, sugars from cellulose and other materials,
sugarcane juice, sugarcane syrup, molasses, fruit juice and
concentrates, purified sugars such as sucrose, glucose, fructose,
maltose, and syrup mixtures containing simple sugars such as those
found in drinks syrups.
[0022] In the preferred embodiment, such feed stocks are
beneficially tested for initial concentrations. Feed stocks falling
within desired ranges (such as, for example, between 15 and 30
degrees BRIX [.degree. Bx]) can be directly introduced with
nutrient amendment into the seeding system. Feed stocks having
higher concentrations can be diluted to meet desired
specifications.
[0023] In the preferred embodiment, feed streams can be maintained
for 8-10 hours. Make up water is provided from clean or recycled
sources within the distillation component of the production system.
Makeup water, nutrients (such as nitrogen, sulfur, and/or
phosphorus containing compounds) and/or antibiotics can be added to
the feed stream prior to reactor injection. The pre-fermentation
tanks utilize mixing to ensure a homogeneous feed for reactor
injection.
[0024] Amended feed stocks enter the bottom of the microbial
generation reactor. In the preferred embodiment, injection of
oxygen from air or other oxygen source using a MBG is computer
controlled allowing for oxygenation of the reaction for variable
times--generally 45 minutes or less in every 6 or more hours of
microbial growth. For the remainder of the generation cycle the
reactor is maintained under anaerobic conditions. The oxygenation
step of the run cycle allows for enhanced growth of microbial cells
and removal of built up residual materials within the reactor.
[0025] Flow rates through the reactors can be adjusted based upon
seeding volume desired. Reactor sizes can be varied and the void
volume within the reactors either filled or partially filled with
inoculated media. Reactor size for seeding systems typically
depends on the capacity of the alternative fuels plant. Off gases
are recaptured using a vacuum system which then returns gases to
the MBG.
Data Set 1
[0026] These data were produced using an immobilized yeast culture
of Saccharomyces cerevisiae. Cell growth in preliminary tests
indicated 10 9 cells/g biocarrier was achievable in a 3% ethanol
broth. Main sugar source within broth was either purified sucrose
and micro nutrients or molasses and micronutrients. Data sets
reflect ethanol yield of 17-20% without affecting yeast production,
immobilization, or feedback inhibition.
[0027] Table 1 and FIG. 2 reflect acceptable biomass production
using the IMBR system as a seeding device for conventional
submerged tank fermentation. Two bench scale IMBR reactors with an
1800 ml void volume were run in series, that is the entire flow
passed into the first reactor and then into the second reactor,
before the material was deposited into a submerged fermentation
tank for final polishing. Aeration periodically was provided by a
low flow air source on a timer to allow for appropriate oxygenation
to promote cellular growth.
[0028] Samples were taken from feed to monitor initial Total
Reducing Sugars in fermented medium (TRSf) and after fermentation
to determine residual sugar content. A refractometer was used to
read initial and final sugar content. Ethanol production was
determined via mass distillation and recovery.
[0029] As the micro-column population acclimated to the presence of
ethanol, the overall alcohol content/production increased until a
maximum production of .about.20 g/L was detected at 72 hours
continuous flow and feeding.
TABLE-US-00001 TABLE 1 Submerged Tank Fermentation: IMBR system as
seeding system Initial Control Residual Ethanol Time (hours)
TRSf(g/L) TRSf(g/L) Yield (g/L) 0 160 160 3 162 144 6 158 151 9 161
133 11 12 160 144 12 15 157 151 12 22 162 98 13 28 158 97 18 32 155
91 18 39 159 89 19 42 157 88 19 48 158 84 19 52 156 78 21 60 160 71
20 72 160 69 21
Data Set 2
[0030] Using the IMBR reactor in a parallel recycle mode similar to
conventional submerged tank fermentation improved ethanol yields
from 21 g/L to 41 g/L for a feed of 160.+-.12 g/L TRSf. (see Table
2/FIG. 3). The reactors were fed in parallel rather than in series
with a portion of the primary fermentation tank volume recycled to
the IMBRs for further polishing. The primary fermentation tank
provided only minimal addition to ethanol content as produced from
direct contact with IMBR columns.
TABLE-US-00002 TABLE 2 Parallel Feed Fermentation using an IMBR
system with tanks Feed Export Ethanol Time (hours) TRSf(g/L)
TRSf(g/L) Yield (g/L) 0 160 160 3 162 108 6 158 101 9 161 98 12 12
157 95 15 15 157 89 28 22 162 84 32 28 158 88 38 32 155 78 45 39
159 75 41 42 157 72 41 48 158 77 42 52 156 58 42 60 158 58 38 72
154 49 39 96 151 55 38 110 162 59 32 120 161 34 35 140 158 35
34
[0031] Thus, it is an object of the present invention to provide a
process for permanent immobilization of microbes (such as yeast,
Saccharomyces cerevisiae, or bacterial consortia having one or more
beneficial organisms) on a substrate for the purpose of enhancing
fermentation of carbohydrate based feed stocks to produce bio-fuels
and/or other alternative fuels including, but not limited to,
ethanol, butanol, methanol, biodiesel and others. Such process
beneficially increases the population of such organisms allowing
for highly concentrated and consistent populations for fermentation
in a traditional fermentation system, while allowing for
maintenance of a pure culture suppressing infection by other
microbial species within the fermentation system.
[0032] It is a further object of the present invention to reduce
the time for fermentation of stock material to alternative fuel
source as compared to traditional fermentation systems, as well as
a reduction in the size of the subject fermentation system.
[0033] It is a further object of the present invention to utilize
an ultra-efficient aeration system, such as one or more immobilized
microbe bioreactors, to enhance growth and stability of microbial
populations through cycling of aerobic and anaerobic conditions
during selected time periods. The flow through an IMBR cluster can
be tailored to accommodate feed stocks so that each IMBR within a
cluster can run in parallel, or in series, as desired.
[0034] It is a further object of the present invention to
beneficially cycle aerobic and anaerobic conditions to enhance
microbe growth, as well as population acclimation, to increasing
alternative fuel material concentrations as found under
fermentation conditions.
[0035] The seeding system of the present invention, when using food
grade materials and control, is appropriate for the generation of
microbes for use in food related fermentation such as the
production of beer, wine, cheese, yogurt, and other fermented food
products. Likewise, the seeding system of the present invention,
when using medical grade materials and control, is appropriate for
the generation of medical related microbes and the materials they
manipulate or generate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] The foregoing summary, as well as the following detailed
description of the preferred embodiments, is better understood when
read in conjunction with the appended drawings. For the purpose of
illustrating the invention, the drawings show certain preferred
embodiments. It is understood, however, that the invention is not
limited to the specific methods and devices disclosed.
[0037] FIG. 1 depicts a schematic layout of the seeding system of
the present invention incorporated within a conventional ethanol
production system.
[0038] FIG. 2 depicts a graphical representation of the data set
displayed in Table 1.
[0039] FIG. 3 depicts a graphical representation of the data set
displayed in Table 2.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
[0040] FIG. 1 depicts a schematic layout of the seeding system of
the present invention incorporated within a conventional ethanol
production system. It is to be observed that the seeding system of
the present invention can function as a stand-alone system, or can
be incorporated within a traditional fermentation process and
system.
[0041] For illustration purposes, such conventional ethanol
production system comprises various components for treatment of
feed stocks, including hammer mill 1, slurry tank 2, steam input
line 3, and liquefaction tank 4. Additionally, optional additive
supply tank 5 (for enzymes or other desired additives) and mash
cooking component 6 can be provided. It is to be observed that the
aforementioned components of conventional ethanol production system
are generally well known in the art; Further, the selection of such
components is generally dictated by the type and quality of feed
stock utilized, and may be varied (with certain components being
added or deleted) depending upon a particular application.
[0042] In the preferred embodiment, the seeding system of the
present invention generally comprises at least one pre-fermentation
nutrient amendment/antibiotic tank 110 (and associated pump, not
shown in FIG. 1); make-up water line(s) 111 for feed stock
concentration control; at least one pre-fermentation mixing/holding
tank 112 to ensure homogeneity of feed prior to reactor injection;
at least one immobilized microbe bioreactor ("IMBR") microbial
generation reactor 113; and at least one surge tank 114 for
consistent flow of seeding material to secondary fermentation
tanks.
[0043] In most cases, the present invention beneficially includes a
plurality of IMBR microbial generation reactors 113 arranged in a
cluster. Such IMBR microbial generation reactors 113 further
include at least one oxygen source (not depicted in FIG. 1) for
periodic oxygenation of such IMBR microbial generation reactors
113. Oxygen can be introduced as air pumped via conventional fans
or air blowers, or as pure oxygen.
[0044] In the preferred embodiment, microbial generation and
seeding is accomplished using IMBR technology. As set forth above,
such IMBR technology beneficially utilizes at least one bio-carrier
medium inoculated with desired microbes; said at least one
bio-carrier medium can include, without limitation, porous
diatomaceous earth solids (such as described in U.S. Pat. No.
4,859,594 and U.S. Pat. No. 4,775,650, which are incorporated
herein by reference). In the preferred embodiment, said at least
one bio-carrier medium is beneficially coated with a thin film of
chitin or other substance. Yeast cells or other beneficial microbes
are immobilized on the surfaces of such at least one bio-carrier
medium. Further, in the preferred embodiment, at least one micro
bubble generator (MBG) immobilized cell reactor (for example, the
MBG more fully disclosed in U.S. Pat. No. 5,534,143, which is
incorporated herein by reference) is provided for periodic aeration
and nutrient addition to a liquid column with bottom-up flow.
[0045] By promoting in-situ growth of desired yeast and/or other
microbial populations, the present invention promotes microbial
growth and acclimation within the fermentation tanks, piping and
associated elements of the present invention. Over time, the
microbial growth provided by the present invention can result in
the spread of yeast and/or other beneficial microbial agents
throughout the system, thereby improving the fermentation process
and overall system efficiency.
[0046] In operation, the seeding system of the present invention is
utilized in connection with conventional ethanol fermentation
system depicted in FIG. 1. At least one feed stock is supplied at
the inlet of said conventional fermentation system (which, in FIG.
1, is depicted as hammer mill 1). Varying feed stocks can be used
for fermentation including, but not limited to, sugars from
cellulose and other materials, sugarcane juice, sugarcane syrup,
bagasse, corn, molasses, fruit juice and concentrates, purified
sugars such as sucrose, glucose, fructose, maltose, and syrup
mixtures containing simple sugars such as those found in drinks
syrups.
[0047] In the preferred embodiment, such feed stocks are
beneficially tested for initial concentrations. Feed stocks falling
within desired ranges [such as, for example, between 15 and 30
degrees BRIX (.degree. Bx)] can be directly introduced with
nutrient amendment (from at least one pre-fermentation nutrient
amendment/antibiotic tank 110) into the seeding system of the
present invention. Feed stocks having higher concentrations can be
diluted to meet desired specifications using water source line(s)
111.
[0048] In the preferred embodiment, make up water is provided from
clean or recycled sources via water line(s) 111 within the
distillation component of the production system. Makeup water,
nutrients (such as nitrogen, sulfur, and/or phosphorus containing
compounds) and/or antibiotics can be added to the feed stream prior
to reactor injection via at least one pre-fermentation nutrient
amendment/antibiotic tank 110. Mixing can be provided in
pre-fermentation tank(s) 112 to ensure a homogeneous feed for
reactor injection.
[0049] High quality feed stock is collected in holding tanks
(volume) prior to amendment and held for no more than 8-12 hours
before nutrient and antibiotic addition to the stream. In the
preferred embodiment, mixing is continuous in both the holding
tanks and the pre-fermentation mixing tanks during microbial
generation to maintain desired BRIX value (usually 10 or higher).
BRIX values of the feed stock to the main fermentation plant may
also be used as a seeding influent. Automatic sampling and testing
of feed stock concentration is beneficially used to monitor
concentration and determine makeup water volume to be added in the
mixing tank. In the preferred embodiment, nutrient addition occurs
as needed based upon observed BRIX values. Antibiotics can also be
added based upon feed concentration.
[0050] In the preferred embodiment of the present invention,
amended feed stocks enter the bottom of IMBR microbial generation
reactors 113. Injection of oxygen from air or other oxygen source
using a Micro bubble Generator (MBG) is beneficially computer
controlled, allowing for oxygenation of the reaction for variable
times. Although it is subject to adjustment, such times will
generally be 45 minutes or less in every 6 or more hours of
microbial growth. For the remainder of each generation cycle, the
reactor can be beneficially maintained under anaerobic conditions.
The oxygenation step of the run cycle allows for enhanced growth of
microbial cells and removal of built up residual materials within
the reactor.
[0051] An electronically monitored and controlled aeration protocol
may be used to maintain appropriate oxygenation to speed microbial
growth without loss of total alternative fuels production and
microbial acclimation. Oxygen sensors can be used to detect oxygen
levels within reactor outflow during the aeration cycle.
[0052] Flow rates through the reactors can be tailored based upon
seeding volume desired. Reactor sizes can be varied and the void
volume within the reactors either filled or partially filled with
inoculated media. Reactor size for seeding systems depends on the
capacity of the alternative fuels plant. In the preferred
embodiment, off gases (including, without limitation, CO2) can be
recaptured using a vacuum system 115 and returned to the MBG. In
the preferred embodiment, split flow supplies feed material to
microbial generation reactors 113, typically arranged in a cluster,
and main fermentation tanks 116 (having an outlet for the removal
of settled solids) at a rate depending upon the capacity of the
plant.
[0053] For generation of microbes, reactors can be fed in series
where a first reactor receives standardized amended feed, which is
thereafter sent to reactor 2 via a surge tank. Alternatively, both
reactors can receive separate constant feed for generation of
microbes to be collected in a surge tank for continuous feed to the
primary fermentation step. A high flow rate will ensure maintenance
of the exponential growth stage in microbial lifecycles, and
partial generation of alternative fuels will maintain a culture
acclimated to increased alternative fuels concentrations.
[0054] Microbial concentration can be monitored daily to ensure
constant and concentrated seeding to the primary fermentation tank.
Samples can be pulled from multiple locations within the
reactors.
[0055] Although the specific components of conventional ethanol
production system may vary, FIG. 1 depicts out flow from main
fermentation tanks 116 piped to pre-distillation surge tank 7.
Fluids from such pre-distillation surge tank can then be directed
to distillation plant 8, having recovered water line 9. In the
preferred embodiment, recovered water line 9 is in fluid
communication with make-up water line 111. Following distillation,
ethanol product can be directed to storage tank 10 for subsequent
handling.
[0056] The above-described invention has a number of particular
features that should preferably be employed in combination,
although each is useful separately without departure from the scope
of the invention. While the preferred embodiment of the present
invention is shown and described herein, it will be understood that
the invention may be embodied otherwise than herein specifically
illustrated or described, and that certain changes in form and
arrangement of parts and the specific manner of practicing the
invention may be made within the underlying idea or principles of
the invention.
* * * * *