U.S. patent application number 14/171350 was filed with the patent office on 2014-08-07 for system and method of applying carbon dioxide during the production of concrete.
The applicant listed for this patent is Eric Alan Burton, Michael Lee. Invention is credited to Eric Alan Burton, Michael Lee.
Application Number | 20140216303 14/171350 |
Document ID | / |
Family ID | 51258162 |
Filed Date | 2014-08-07 |
United States Patent
Application |
20140216303 |
Kind Code |
A1 |
Lee; Michael ; et
al. |
August 7, 2014 |
SYSTEM AND METHOD OF APPLYING CARBON DIOXIDE DURING THE PRODUCTION
OF CONCRETE
Abstract
The present disclosure involves systems and methods for applying
CO2 to concrete, which may be performed in-situ or through a
separate, stand-alone process. According to another embodiment
disclosed herein, a system and method for applying CO2 to one or
more materials used in the production of concrete is also
provided.
Inventors: |
Lee; Michael; (Colorado
Springs, CO) ; Burton; Eric Alan; (Palmer Lake,
CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lee; Michael
Burton; Eric Alan |
Colorado Springs
Palmer Lake |
CO
CO |
US
US |
|
|
Family ID: |
51258162 |
Appl. No.: |
14/171350 |
Filed: |
February 3, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61760319 |
Feb 4, 2013 |
|
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Current U.S.
Class: |
106/638 |
Current CPC
Class: |
B28C 5/462 20130101;
C04B 22/10 20130101; B01F 3/06 20130101; B28C 5/468 20130101; F25B
19/005 20130101; B01F 2215/0047 20130101; B01F 5/04 20130101; B01F
2015/061 20130101; C04B 40/0032 20130101; B28C 7/0418 20130101;
C04B 28/02 20130101; Y02P 40/18 20151101; C04B 40/0231 20130101;
B01F 15/063 20130101; B01F 15/00344 20130101; B01F 3/18 20130101;
C04B 28/02 20130101; C04B 22/10 20130101; C04B 40/0032 20130101;
C04B 28/02 20130101; C04B 40/0231 20130101 |
Class at
Publication: |
106/638 |
International
Class: |
C04B 14/00 20060101
C04B014/00 |
Claims
1. An apparatus for applying carbon dioxide to concrete or concrete
materials, the apparatus comprising: a storage container for
storing liquid carbon dioxide; at least one load cell for
determining a weight of the storage container and the carbon
dioxide stored therein, the at least one load cell in communication
with a system controller, the at least one load cell operable to
transmit information related to the weight to the system
controller; piping interconnecting the storage container to an
injection assembly, the piping operable to transport carbon dioxide
to the injection assembly, the piping adapted to maintain the
carbon dioxide in a liquid state; a control valve proximate to the
storage container, the control valve operable to prevent carbon
dioxide from entering the piping when provided in a closed
configuration, the control valve operable to enable carbon dioxide
to enter the piping when provided in an open configuration, and the
control valve provided in communication with the system controller;
a liquid-gas separator in fluid communication with the piping, the
liquid-gas separator operable to separate gaseous carbon dioxide
from liquid carbon dioxide before the injection assembly receives
the carbon dioxide, the liquid-gas separator having a vent to
release the gaseous carbon dioxide; the injection assembly operable
to receive carbon dioxide from the piping and operable to inject
carbon dioxide into a concrete mixer or a concrete material
container; and the system controller operable to control the
control valve and the injection assembly.
2. The apparatus of claim 1, wherein the system controller is
operable to send a signal to move the control valve to the closed
configuration when the system controller determines that the weight
of the storage container and the carbon dioxide stored therein has
decreased by a predetermined amount.
3. The apparatus of claim 1, wherein the system controller is
operable to send a signal to move the control valve to the closed
configuration after a predetermined amount of time.
4. The apparatus of claim 1, further comprising a mass flow
controller in fluid communication with the piping, the mass flow
controller operable to measure a mass of carbon dioxide that flows
through the mass flow controller, the mass flow controller in
communication with the system controller, the mass flow controller
operable to transmit information related to the mass to the system
controller.
5. The apparatus of claim 4, wherein the system controller is
operable to send a signal to move the control valve to the closed
configuration when the system controller determines that a
predetermined mass of carbon dioxide has flowed through the mass
flow controller.
6. The apparatus of claim 1, wherein the interconnection of the
piping to the storage container is adapted to extract only liquid
carbon dioxide from the storage container.
7. The apparatus of claim 1, further comprising a liquid carbon
dioxide sensor operable to determine when gaseous carbon dioxide is
in contact with the control valve of the piping, wherein the liquid
carbon dioxide sensor is in communication with the system
controller and operable to transmit information related to the
contact to the system controller, wherein the system controller is
operable to send a signal to move the control valve to the closed
configuration when the liquid carbon dioxide sensor determines that
gaseous carbon dioxide is in contact with the control valve.
8. The apparatus of claim 1, wherein gaseous carbon dioxide
separated from liquid carbon dioxide by the liquid-gas separator is
returned to the storage container by second piping interconnecting
the storage container to the vent of the liquid-gas separator.
9. The apparatus of claim 1, wherein the injection assembly is
operable to cause a temperature of carbon dioxide to decrease to no
more than about -109.degree. F. when carbon dioxide passes through
the injection assembly.
10. The apparatus of claim 1, wherein the injection assembly is
operable to inject between about 1 and about 27 pounds of carbon
dioxide into the mixer or material container for each cubic yard of
concrete mix in the mixer or the material container.
11. The apparatus of claim 1, wherein the injection assembly is
operable to cause carbon dioxide to change state to a mixture of
solid carbon dioxide and gaseous carbon dioxide and to inject the
mixture of solid and gaseous carbon dioxide into the mixer.
12. The apparatus of claim 1, further comprising the material
container, wherein the material container has a plurality of
injectors with outlets facing an interior chamber of the material
container, wherein inlets of the plurality of injectors are
interconnected to the injection assembly, and wherein the system
controller is operable to control each of the plurality of
injectors.
13. The apparatus of claim 1, further comprising the mixer, wherein
the mixer has a mixing chamber with an aperture, wherein the mixing
chamber is operable to receive carbon dioxide from the injection
assembly, wherein the mixing chamber is operable to receive a
predetermined amount of concrete materials, and wherein the mixing
chamber is operable to mix the carbon dioxide and the predetermined
amount of concrete materials.
14. The apparatus of claim 13, further comprising a closure
interconnected to the mixer operable to seal the aperture of the
mixing chamber, wherein the mixing chamber is pressurized after the
closure seals the aperture, and wherein the mixing chamber is
operable to mix the carbon dioxide and the predetermined amount of
concrete materials in the pressurized mixing chamber.
15. The apparatus of claim 13, wherein the controller is operable
to send signals to start and stop the mixer, and wherein the
controller is operable to send signals to open and close one or
more pressure release valves interconnected to the mixing chamber
of the mixer.
16. A method of applying carbon dioxide to concrete during the
production of the concrete, the method comprising: determining if
there is sufficient carbon dioxide in a storage container; after
determining there is sufficient carbon dioxide in the storage
container, starting a mixer; placing a predetermined amount of
concrete materials in a mixing chamber of the mixer, wherein the
mixing chamber has an aperture; determining if an injection
assembly is in a position to inject carbon dioxide into the mixing
chamber of the mixer, wherein the injection assembly is in fluid
communication with the storage container by piping interconnected
to the storage container, a control valve, a liquid-gas separator,
and the injection assembly; after determining the injection
assembly is in the position to inject carbon dioxide into the
mixing chamber, moving the control valve to an open configuration
to allow liquid carbon dioxide to leave the storage container and
enter the piping; separating gaseous carbon dioxide from liquid
carbon dioxide in the piping by the liquid-gas separator, wherein
gaseous carbon dioxide is released from the piping through a vent
to the atmosphere, and wherein liquid carbon dioxide continues
through the piping to the injection assembly; injecting carbon
dioxide into the mixing chamber of the mixer by the injection
assembly, wherein the injection assembly is operable to cause
liquid carbon dioxide to change state to a mixture of solid carbon
dioxide and gaseous carbon dioxide; determining that a
predetermined amount of carbon dioxide has been injected into the
mixing chamber of the mixer; after determining that the
predetermined amount of carbon dioxide has been injected into the
mixing chamber, moving the control valve to a closed configuration
to prevent liquid carbon dioxide from leaving the storage
container; mixing the concrete materials and the carbon dioxide
until a chemical reaction between the concrete materials and the
carbon dioxide is complete; and discharging the concrete from the
mixing chamber of the mixer.
17. The method of claim 16, further comprising: sealing the
aperture of the mixing chamber with a closure after placing the
concrete materials and carbon dioxide in the mixing chamber; and
increasing the pressure in the mixing chamber after sealing the
aperture of the mixing chamber.
18. The method of claim 16, further comprising adding at least one
of a water reducer and an air entrainment agent to the concrete
materials in the mixing chamber of the mixer.
19. The method of claim 16, wherein determining that the
predetermined amount of carbon dioxide has been injected into the
mixing chamber of the mixer comprises as least one of measuring a
weight of the storage container and measuring a mass of carbon
dioxide that has flowed from the storage container.
20. A method of applying carbon dioxide to concrete materials used
in the production of the concrete, the method comprising: providing
a supply of carbon dioxide in a storage container; placing concrete
materials in a chamber of a material container, wherein the
material container has a plurality of injectors, wherein the
injectors have an inlet on an exterior surface of the chamber, and
wherein the injectors have an outlet directed into the chamber;
interconnecting the storage container to the inlets of the
plurality of injectors of the material container; moving a control
valve in fluid communication with the storage container and the
plurality of injectors to an open configuration to allow carbon
dioxide to leave the storage container and pass through the
plurality of injectors into the chamber of the material container;
and moving the control valve to a closed configuration after
determining that a sufficient amount of carbon dioxide has been
added to the concrete materials in the material container.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of priority from
co-pending U.S. Provisional Patent Application No. 61/760,319,
filed Feb. 4, 2013, the entire disclosure of which is hereby
incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] Embodiments of the present invention generally relate to
systems and methods used in the production of concrete. More
particularly, the present disclosure relates to systems and methods
for using carbon dioxide during the production of concrete.
BACKGROUND OF THE INVENTION
[0003] The production of cement and concrete are well known in the
art. Concrete has many uses that are highly beneficial in many
industries and can be produced to perform many functions. For
example, concrete is widely used in commercial construction and for
municipal projects. The concrete used in these projects may be
pre-heated, pre-stressed, and reinforced.
[0004] Unfortunately, both the production of the cement used in
concrete and the production of concrete are known to produce large
amounts of carbon dioxide (CO2). According to the US Energy
Information Administration, cement manufacturers are a significant
source of carbon dioxide pollution in the atmosphere. When cement
is produced, the limestone feedstock is heated and CO2 is released
from the limestone. Cement manufacturers use a significant amount
of energy in the cement manufacturing process to heat the limestone
feedstock resulting in further CO2 releases and hydrocarbon
emissions. Systems and methods are known that have attempted to
entrain CO2 in the mixed concrete to reduce the CO2 emissions into
the atmosphere. Other systems and methods have attempted to use CO2
to strengthen the concrete. However, all of these known systems and
methods have drawbacks or problems associated therewith which are
addressed in the present disclosure.
SUMMARY OF THE INVENTION
[0005] Embodiments of the present invention contemplate novel
processes and apparatus directed to the use of carbon dioxide (CO2)
in the production of concrete and/or materials used for producing
concrete. Applying CO2 to concrete and/or to concrete materials
prior to or during production of the concrete according to the
systems and methods of embodiments of the present invention has
many benefits compared to prior art methods of producing
concrete.
[0006] Among the many benefits of embodiments of the present
invention are a reduction in the amount of cement needed during
concrete production and decreased energy consumption for the
production of concrete. The addition of CO2 to concrete in
accordance with embodiments of the present invention results in a
reduction in the cement component weight per unit of concrete,
typically measured in pounds cement per cubic yard of concrete or
kilograms cement per cubic meter of concrete. By weight and by
volume, cement is typically the most expensive part of the large
components of the concrete mix. By treating the concrete with CO2,
the total cost of a cubic meter or cubic yard of concrete is
reduced. In addition to reducing the amount of cement required to
produce concrete and the corresponding reduction in the cost
associated with cement in the concrete mix, the total cost of
production of concrete is reduced by adding CO2 to the concrete,
allowing a cubic yard of concrete or cubic meter of concrete to be
produced at a lower total cost.
[0007] A further benefit of the addition of CO2 to the concrete mix
is an increase in the ratio of water to cement that may be used to
produce the concrete. Freshly mixed concrete produced using the
methods and systems of the present invention achieves a required
slump, a measure of the workability of freshly mixed concrete,
although the ratio of water to cement used to produce the concrete
is greater than is possible for concrete produced using known
methods. Thus, the present invention improves the consistency and
workability of the freshly mixed concrete.
[0008] It is one aspect of the present invention to provide systems
and methods of producing concrete with increased break strength and
increased break strength consistency compared to concrete produced
using known methods. The addition of CO2 to concrete according to
embodiments of the present invention measurably improves the break
strength of the concrete, a key physical property of concrete,
compared to control samples of concrete produced using known
methods. Break strength tests of concrete samples produced and
treated with CO2 using the methods and apparatus of embodiments of
the present invention show that the variability of break strength
is reduced between 50% and 80% compared to concrete produced using
other known methods. Further, treating concrete with CO2 results in
a more consistent concrete mix. Thus, the present invention allows
concrete producers and users to formulate more precise concrete mix
designs for the desired structural properties of the concrete
treated with CO2.
[0009] Another benefit of the present invention is a reduction in
the temperature of the fresh mix concrete. When liquid carbon
dioxide is injected from a tank or storage container into a mixer,
the liquid carbon dioxide changes phase to both gaseous and solid
carbon dioxide at atmospheric pressure. At atmospheric pressure,
the solid CO2 must be -109.degree. F. (-78.5.degree. C.) or less.
Consequently, CO2 applied to mixing concrete according to
embodiments of the present invention cools the fresh concrete mix
in proportion to the amount of CO2 injected into the concrete mix.
Reducing the temperature of fresh mix concrete is known to increase
the strength of the cured concrete. Methods and apparatus to reduce
the temperature of concrete are generally known in the art as
disclosed in U.S. Pat. No. 8,584,864 and U.S. patent application
Ser. No. 14/056,139 which are incorporated herein in their entirety
by reference. Thus, by cooling the concrete mix, embodiments of the
present invention increase the strength of the resulting cured
concrete.
[0010] The systems and methods of embodiments of the present
invention also produce concrete with reduced permeability and a
reduced degradation rate, thereby increasing the service life of
the concrete and structures made with the concrete. Those of skill
in the art know that the carbonation level of concrete increases
over time, reducing the permeability of the concrete. In other
words, the small interstitial spaces within the concrete are filled
in by the carbonation products from the carbonation reaction. The
present invention speeds up the carbonation process resulting in an
initial concrete product with less permeability compared to
concrete produced using known methods. A less permeable concrete is
less susceptible to environmental degradation which occurs when
oxygen, water, and other liquids or contaminates permeate the
concrete and cause oxidation (or "rust") of the steel reinforcing
members within the concrete. Normal freeze/thaw cycles can also
reduce the strength of the concrete permeated by oxygen, water, and
other liquids by creating fissures within the concrete structure.
Thus, structures made with concrete produced by embodiments of the
systems and methods of the present invention have an increased
service life.
[0011] Embodiments of the present invention also help decrease the
CO2 footprint of cement and concrete production by trapping and/or
sequestering CO2 in the concrete and reacting with CO2 during
hydration of the cement during the concrete mixing process. The
amount of energy consumed during the production of concrete using
methods and systems of the present invention is also reduced
because the amount of cement required to produce a given amount of
concrete is reduced. By consuming CO2 in the production of
concrete, the present invention reduces emissions of CO2, a known
greenhouse gas believed to contribute to global warming, during the
production of concrete. In addition, by reducing the amount of
cement needed to produce concrete, embodiments of the present
invention further reduce energy consumption and greenhouse gas
emissions of cement manufacturers.
[0012] It is another aspect of embodiments of the present invention
to provide a system and method for applying CO2 in a concrete
production process. According to varying embodiments, this
application may take the form of entraining, sequestering or
consuming CO2 during the production of concrete or concrete
material(s) used in the production of concrete. In varying
embodiments described herein, the system and method may be
performed "in-situ" where the materials for producing concrete are
stored (such as in large containers or "pigs," or other storage
devices at the production site) or may alternatively be performed
through a separate sub-process. Embodiments of the present
invention trap and/or sequester CO2 in the concrete resulting in
reduced CO2 emissions during the production of concrete and
decreasing greenhouse gas pollution. Applicant's invention includes
special controls, injections, and devices to apply CO2 during the
production of concrete, which are described and shown below.
[0013] In one embodiment, an apparatus for applying carbon dioxide
to concrete or concrete materials is provided. The apparatus
includes a storage container for storing liquid carbon dioxide. At
least one load cell is affixed to the storage container for
determining a weight of the storage container and the carbon
dioxide stored therein. The at least one load cell is in
communication with a system controller and the at least one load
cell is operable to transmit information related to the weight to
the system controller. Piping interconnects the storage container
to an injection assembly. The piping is operable to transport the
carbon dioxide to the injection assembly. The piping is operable at
a temperature and at a pressure required to maintain the carbon
dioxide in a liquid state. In one embodiment, the interconnection
of the piping to the storage container is adapted to extract only
liquid carbon dioxide from the storage container. A control valve
is proximate to the storage container and is operable to prevent
carbon dioxide from entering the piping when the control valve is
in a closed configuration and the control valve enables carbon
dioxide to enter the piping when the control valve is in an open
configuration. The control valve is in communication with the
system controller.
[0014] The apparatus includes a liquid-gas separator in fluid
communication with the piping to separate gaseous carbon dioxide
from liquid carbon dioxide before the injection assembly receives
the carbon dioxide. The liquid-gas separator has a vent to release
the gaseous carbon dioxide from the apparatus. In one embodiment,
the gaseous carbon dioxide is released through the vent to the
atmosphere. In another embodiment, the gaseous carbon dioxide
separated from liquid carbon dioxide by the liquid-gas separator is
returned to the storage container by second piping interconnecting
the storage container to the vent of the liquid-gas separator.
[0015] The injection assembly receives carbon dioxide from the
piping and injects carbon dioxide into a concrete mixer or a
concrete material container. In one embodiment, the injection
assembly is operable to cause a temperature of carbon dioxide to
decrease to no more than about -109.degree. F. when carbon dioxide
passes through the injection assembly. In another embodiment, the
injection assembly injects between about 1 and about 27 pounds of
carbon dioxide into the mixer or concrete material container for
each cubic yard of concrete mix in the mixer or the material
container. In still another embodiment, the injection assembly is
operable to cause carbon dioxide to change state to a mixture of
solid carbon dioxide and gaseous carbon dioxide and to inject the
mixture of solid and gaseous carbon dioxide into the mixer.
[0016] The system controller is operable to control the control
valve, the injection assembly, the liquid-gas separator, the mixer,
and other sensors and controlled devices in communication with the
system controller. In one embodiment, the system controller is
operable to send a signal to move the control valve to the closed
configuration when the system controller determines that the weight
of the storage container and carbon dioxide stored therein has
decreased by a predetermined amount. In another embodiment, the
system controller is operable to send a signal to move the control
valve to the closed configuration after a predetermined amount of
time.
[0017] In one embodiment, the apparatus further comprises a mass
flow controller in fluid communication with the piping and in
communication with the system controller. The mass flow controller
measures a mass of carbon dioxide that flows through the mass flow
controller and transmits information related to the mass to the
system controller. The system controller is operable to send a
signal to move the control valve to the closed configuration when
the system controller determines that a predetermined mass of
carbon dioxide has flowed through the mass flow controller. In
still another embodiment, the apparatus further includes a liquid
carbon dioxide sensor operable to determine when gaseous carbon
dioxide is in contact with the control valve of the piping. The
liquid carbon dioxide sensor is in communication with the system
controller and operable to transmit information related to the
contact to the system controller. The system controller is operable
to send a signal to move the control valve to the closed
configuration when the liquid carbon dioxide sensor determines that
gaseous carbon dioxide is in contact with the control valve. In yet
another embodiment of the present invention, the apparatus is
controlled by the system controller.
[0018] In one embodiment, the apparatus further comprises the
material container. The material container includes a plurality of
injectors with outlets facing an interior chamber of the material
container. The plurality of injectors include inlets on an exterior
surface of the material container. The inlets of the plurality of
injectors are interconnected to the injection assembly. In still
another embodiment, the material container includes a closure to
seal the interior chamber and the interior chamber can be
pressurized after it is sealed. The system controller is operable
to control the inlets of the plurality of injectors and can send
signals to open and close one or more pressure valves
interconnected to the material container to increase or decrease
the pressure within the interior chamber. The system controller is
further operable to control each of the inlets of the plurality of
injectors individually and to control the one or more pressure
valves individually. Thus, the system controller can send a signal
to decrease a flow of carbon dioxide to one inlet or to a plurality
of inlets, and can send a second signal to a second inlet or to a
plurality of inlets to increase a flow of carbon dioxide through
the second inlet or plurality of inlets.
[0019] In another embodiment the apparatus includes the mixer. The
mixer has a mixing chamber with an aperture. The mixing chamber
receives carbon dioxide from the injection assembly and the
predetermined amount of concrete materials. The mixing chamber is
operable to mix carbon dioxide and the predetermined amount of
concrete materials. In yet another embodiment, a closure is
interconnected to the mixer to seal the aperture of the mixing
chamber and the mixing chamber is pressurized after the closure
seals the aperture. The mixing chamber is operable to mix carbon
dioxide and the predetermined amount of concrete materials in the
pressurized mixing chamber. In still another embodiment, the
controller is operable to send signals to start and stop the mixer,
to open and close the closure, to send signals to open and close
one or more pressure release valves interconnected to the mixing
chamber of the mixer.
[0020] It is another aspect of embodiments of the present invention
to provide a method of applying carbon dioxide to concrete during
the production of the concrete, the method generally comprising:
(1) determining if there is sufficient carbon dioxide in a storage
container; (2) after determining there is sufficient carbon dioxide
in the storage container, starting a mixer; (3) placing a
predetermined amount of concrete materials in a mixing chamber of
the mixer, wherein the mixing chamber has an aperture; (4)
determining if an injection assembly is in a position to inject
carbon dioxide into the mixing chamber of the mixer, wherein the
injection assembly is in fluid communication with the storage
container by piping interconnected to the storage container, a
control valve, a liquid-gas separator, and the injection assembly;
(5) after determining the injection assembly is in the position to
inject carbon dioxide into the mixing chamber, moving the control
valve to an open configuration to allow liquid carbon dioxide to
leave the storage container and enter the piping; (6) separating
gaseous carbon dioxide from liquid carbon dioxide in the piping by
the liquid-gas separator, wherein gaseous carbon dioxide is
released from the piping through a vent to the atmosphere, and
wherein liquid carbon dioxide continues through the piping to the
injection assembly; (7) injecting carbon dioxide into the mixing
chamber of the mixer by the injection assembly, wherein the
injection assembly is operable to cause liquid carbon dioxide to
change state to a mixture of solid carbon dioxide and gaseous
carbon dioxide; (8) determining that a predetermined amount of
carbon dioxide has been injected into the mixing chamber of the
mixer; (9) after determining that the predetermined amount of
carbon dioxide has been injected into the mixing chamber, moving
the control valve to a closed configuration to prevent the liquid
carbon dioxide from leaving the storage container; (10) mixing the
concrete materials and carbon dioxide until a chemical reaction
between the concrete materials and carbon dioxide is complete; and
(11) discharging the concrete from the mixing chamber of the mixer.
In one embodiment, the method is controlled by a system
controller.
[0021] Optionally, the method may further comprise sealing the
aperture of the mixing chamber with a closure after placing the
concrete materials and carbon dioxide in the mixing chamber, and
increasing the pressure in the mixing chamber after sealing the
aperture of the mixing chamber. In one embodiment, the method
includes adding at least one of a water reducer and an air
entrainment agent to the concrete materials in the mixing chamber
of the mixer. In one embodiment, the water reducer is BASF
Pozzolith.RTM. 200 N. In another embodiment, the water reducer is
BASF Pozzolith.RTM. 322. In yet another embodiment, the water
reducer is BASF Glenium.RTM. 3400 NV. In one embodiment, the air
entrainment agent is BASF's MB-AE.TM. 90. It shall be understood
that other water reducers, air entrainment agents, and admixtures
may be used with the method and apparatus of the current invention
and are within the scope and spirit of the present invention as
will be recognized by one of ordinary skill in the art.
[0022] In still another embodiment, determining that the
predetermined amount of carbon dioxide has been injected into the
mixing chamber of the mixer comprises as least one of measuring a
weight of the storage container and/or measuring a mass of carbon
dioxide that has flowed from the storage container.
[0023] In another aspect of the present invention, a method of
applying carbon dioxide to concrete materials used in the
production of the concrete is provided. The method generally
comprises: (1) providing a supply of carbon dioxide in a storage
container; (2) placing concrete materials in a chamber of a
material container, wherein the material container has a plurality
of injectors, wherein each of the plurality of injectors has a
valve to control the flow of carbon dioxide through the injector,
wherein each of the plurality of injectors has an inlet on an
exterior surface of the chamber, and wherein each of the plurality
of injectors has an outlet directed into the chamber; (3)
interconnecting the storage container to the inlets of the
plurality of injectors of the material container; (4) moving a
control valve in fluid communication with the storage container and
the plurality of injectors to an open configuration to allow the
carbon dioxide to leave the storage container and pass through the
plurality of injectors into the chamber of the material container;
and (5) moving the control valve to a closed configuration after
determining that a sufficient amount of carbon dioxide has been
added to the concrete materials in the material container. In one
embodiment, a water reducer and/or an air entrainment agent may be
added to the concrete materials in the mixer. In another
embodiment, the water reducer is BASF Pozzolith.RTM. 322. In yet
another embodiment, the water reducer is BASF Glenium.RTM. 3400 NV.
In one embodiment, the air entrainment agent is BASF's MB-AE.TM.
90. It shall be understood that other water reducers, air
entrainment agents, and admixtures may be used with the method and
apparatus of the current invention and are within the scope and
spirit of the present invention as will be recognized by one of
ordinary skill in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a flowchart diagram of a system for applying CO2
in a concrete production process according to a preferred
embodiment of the present invention;
[0025] FIG. 2 is a system for applying CO2 to concrete materials
according to another embodiment of the present invention;
[0026] FIG. 3 is a system for applying CO2 in a concrete production
process according to yet another embodiment of the present
invention;
[0027] FIG. 4 is flowchart diagram of a preferred embodiment of a
method for applying CO2 according to the present invention and
which relates to the system depicted in FIG. 3; and
[0028] FIG. 5 is a block diagram of a system controller according
to an embodiment of the present invention.
[0029] To assist in the understanding of embodiments of the present
invention, the following list of components and associated
numbering found in the drawings is provided below:
[0030] Number Component [0031] 2 System [0032] 4 Storage container
[0033] 6 Piping [0034] 8 Mixer [0035] 10 Tank isolation valve
[0036] 12 Liquid/gas sensing instrument [0037] 14 Automated
injection valve [0038] 16 Injection assembly [0039] 17 Injector
[0040] 18 System [0041] 20 Shut-off valve [0042] 22 Pressure
reducing valves [0043] 24 Gas purifier [0044] 26 Pumping connection
[0045] 28 Flange [0046] 30 Valve [0047] 32 Mass flow controller
[0048] 33 Material container [0049] 34 System [0050] 36 Carbon
dioxide [0051] 38 Load cells [0052] 40 Connection [0053] 42 System
controller [0054] 44 Concrete materials [0055] 46 Position sensors
[0056] 48 User interface [0057] 50 Electronic device [0058] 52
Wired network [0059] 54 Wireless network [0060] 56 Control valve
[0061] 58 Liquid-gas separator [0062] 59 Liquid CO2 sensor [0063]
60 Gaseous carbon dioxide [0064] 62 Inlet [0065] 64 Outlet [0066]
66 Solid carbon dioxide [0067] 68 Concrete [0068] 70 Method [0069]
72 Start [0070] 74 Adjust set point of desired amount of CO2 [0071]
76 Determine amount of CO2 in storage container [0072] 78 Start
mixer [0073] 80 Mixer filled [0074] 82 Determine position of
injector assembly and mixer [0075] 84 CO2 delivery initiated [0076]
86 Control valve opened [0077] 88 CO2 leaves storage container
[0078] 90 Liquid and gaseous CO2 separated [0079] 92 Liquid CO2
enters inlet of injection assembly [0080] 94 Liquid CO2 changes
state [0081] 96 Solid and gaseous CO2 discharged from outlet into
mixer [0082] 98 Determine amount of CO2 delivered [0083] 100
Control valve closed [0084] 102 Determine if concrete mixed and CO2
reaction complete [0085] 104 Concrete discharged [0086] 106 End of
method [0087] 110 Computer [0088] 112 Sensor array [0089] 114
Controlled devices [0090] 116 Memory [0091] 118 Processor [0092]
120 Controller [0093] 122 Display [0094] 124 Input device
DETAILED DESCRIPTION
[0095] Although the following text sets forth a detailed
description containing different elements, it should be understood
that the legal scope of the description is defined by the words of
the claims set forth at the end of this disclosure. The detailed
description is to be construed as exemplary only and does not
describe every possible embodiment since describing every possible
embodiment would be impractical, if not impossible. Numerous
alternative embodiments could be implemented, using either current
technology or technology developed after the filing date of this
patent, which would still fall within the scope of the claims.
[0096] According to certain embodiments of the present invention,
systems and methods of applying CO2 to concrete, or alternatively
to one or more of the concrete materials used in the production of
concrete, are depicted in FIGS. 1-5. Referring now to FIG. 1, a
system 2 for applying CO2 to concrete, or concrete materials,
according to a preferred embodiment is illustrated. A vessel or
storage container 4 is utilized to store liquid CO2. The storage
container 4 may be of any material, shape, or size known to those
of skill in the art and may be positioned generally vertically or
horizontally. Piping 6 or other conduit interconnects the storage
container 4 to a mixer 8 and is utilized to transport a
predetermined amount of CO2 to the mixer 8. The piping 6 may be
flexible or generally rigid. In one embodiment, at least a portion
of the piping 6 is comprised of a flexible ultra-high vacuum (UHV)
hose. Various types of mixers 8 known to those of skill in the art
may be used with the embodiments of the present invention,
including, for example, tilt drum mixers, single and twin shaft
compulsory mixers, paddle mixers, pressurized reactor/mixers, truck
mounted mixers, transit mix trucks continuous mixers, and mixers
with mixing chambers that can be sealed with a closure.
[0097] The system 2 includes one or more of a tank isolation valve
10, a liquid/gas sensing instrument 12, and an automated injection
valve 14 to regulate the flow of CO2 between the storage container
4 and the mixer 8. One or more injection assemblies 16, which may
also be referred to as snow horns, apply the CO2 to the concrete
and/or directly to one or more of the concrete materials used in
the production of concrete. Snow horns suitable for use as
injection assemblies 16 with the current invention are generally
known. For example, U.S. Pat. No. 3,667,242 entitled "Apparatus for
Intermittently Producing Carbon Dioxide Snow by Means of Liquid
Carbon Dioxide," which is incorporated by reference herein in its
entirety, generally discloses an improved snow horn for producing
carbon dioxide snow in a controlled intermittent manner upon
demand.
[0098] The CO2 is generally injected into the mixer 8 while the
concrete materials are beginning to combine during mixing. The CO2
may be applied to the concrete or the concrete materials in a
gaseous, liquid, or solid state. The injection assemblies 16 permit
dispensing the CO2 directly into mixers 8 of all types.
[0099] The injection assemblies 16 may be situated to communicate
CO2 to the concrete mixer 8 in use during production at a concrete
production facility, central mix batch plant, or at a job site.
Alternatively, the concrete mixer 8 may be replaced by a material
container or other structure (including a stack or pile of concrete
materials) housing the concrete or concrete materials used in
producing concrete. For example, carbon dioxide may be delivered by
the system 2 to concrete materials stored at a jobsite using
existing structures and equipment. At the jobsite, cement and other
concrete materials normally rest in a material container, such as,
in the case of cement, a container known as a "pig." The interior
surface of the material containers include a plurality of inwardly
facing injector outlets. Tubing or piping interconnects the inlets
of the plurality of injectors to a source of compressed air. In
known equipment, compressed air is injected into the material
container through one or more of the plurality of injectors into
the concrete materials to "fluidize" the concrete materials such
that they flow out of the material container. In addition,
compressed air is also often injected into cement in delivery
trucks to transfer the cement from the trucks into the storage
facilities. In a preferred embodiment, the systems and methods of
the current invention utilize existing structures and injectors for
fluidizing the concrete materials and cement to apply CO2 to the
concrete and/or concrete materials and to achieve the benefits of
applying CO2 described herein. For example, in one preferred
embodiment, system 2 is interconnected to injectors of a material
container in place of the source of compressed air. When the
concrete material in the material container is required for the
production of a batch of concrete, the system 2 injects compressed
gaseous CO2 from container 4 into the material container through
the plurality of injectors, fluidizing the concrete material and
treating the concrete material with CO2. Each of the plurality of
injectors may be individually controlled such that the flow of CO2
may be precisely controlled and the CO2 can be selectively injected
through some or all of the plurality of injectors. Further, the
rate of the flow of CO2 through each of the plurality of injectors
can be individually controlled such that some injectors may be
partially opened allowing a low rate of flow of CO2, while other
injectors may allow a greater rate of flow of CO2. In alternate
embodiments of the present invention, the application of CO2 is
performed by separate and/or additional equipment, as will be
understood from a review of the detailed description and drawing
figures provided herein.
[0100] In one embodiment, control of the amount of CO2 applied to
the concrete and/or the concrete materials can be accomplished by
connecting load cells (or scales) to the CO2 storage container 4
with constant monitoring of the weight of the container 4 and the
CO2 within the container. A system controller (described below) can
be set to open and close one or more valves when a pre-set weight
of the CO2 has been dispensed from the container 4. Said
differently, once the controller determines that the combined
weight of the storage container 4 and the CO2 therein has decreased
by a predetermined amount corresponding to the desired weight of
CO2 to be injected into the concrete mix, the system controller
will generate a signal to close one or more valves to stop the flow
of CO2 from the storage container 4, ensuring the proper amount of
CO2 has been injected into the concrete and/or concrete materials.
The Applicant has found that injecting too much CO2 into the
process is undesirable and can negatively impact the quality of the
concrete. Thus, monitoring the differential weight of the container
4 to control the amount of CO2 dispensed ensures a predetermined
amount of CO2 is applied to the concrete to achieve the desired
design characteristics of the concrete. The applicant has found
that the addition of between about 1 to 27 pounds of CO2 per cubic
yard of concrete increases the break strength and physical
properties of the concrete mixture. This is just one example and it
should be understood that the amount of CO2 added to the concrete
may vary based upon various design requirements of the concrete and
the components and admixtures added to the concrete. For example,
in one embodiment, more than about 27 pounds of CO2 is added per
cubic yard of concrete.
[0101] Another method of controlling the amount of CO2 applied to
the concrete and/or the concrete materials is by a timed
application. In this embodiment, a timer relay switch is set to
open a valve 10 and allow injection of CO2 into the mix for a set
amount of time. The length of time the valve 10 remains open may be
determined based on the pressure of the CO2 in the storage
container 4 and/or flow rate of the CO2 monitored by the injection
assembly 16. In yet another embodiment, CO2 can be manually added
to the concrete and/or concrete materials by a user manually
opening and closing one or more valves.
[0102] Additional elements and equipment may also be included with
the system 2 for enhancing the system and method disclosed herein.
For example, equipment described in relation to FIGS. 2-5 below may
be used with the embodiment of the present invention described
above in conjunction with FIG. 1.
[0103] Another embodiment of a system 18 for applying CO2 to
concrete or concrete materials is illustrated in FIG. 2. Similar to
the system 2 discussed above, the system 18 has a storage container
4A containing carbon dioxide in fluid communication with an
injection assembly 16A by piping 6A, 6B. The piping includes both
flexible 6A portions and generally rigid 6B portions. The system 18
may include one or more of a shut-off valve 20, pressure reducing
valves 22, a gas purifier 24, a pumping connection 26 with a flange
28, and one or more valves 30. The amount of CO2 applied to the
concrete mix or the concrete materials is controlled by use of a
mass flow controller 32 coupled to a cryogenic control valve 30A.
The mass flow controller 32 measures and continuously reports the
mass of CO2 that has flowed through the mass flow controller 32 to
a system controller (described below). When the system controller
determines that a pre-set mass of CO2 has passed through the mass
flow controller 32, the system controller sends a signal to close
the control valve 30A, the shut-off valve 20, and/or one or more
valves within the injection assembly 16A. Various mass flow
controllers 32 and control valves 30A are commercially available
and suitable for use with embodiments of the present invention. Two
examples of valves that may be used with the present invention
include ASCO.RTM. cryogenic valves and liquid CO2 solenoid valves.
The Sierra.RTM. Instruments InnovaMass.RTM. 240 model cryogenic
mass flow controller is one example of a cryogenic mass flow
controller that is suitable for use in the present invention.
Methods of metering the CO2 by weight, time, mass, or manual
application may be combined and or used alternatively. In one
embodiment, CO2 may be applied to the concrete mix by a combination
of metering CO2 by weight using load cells, by mass in conjunction
with a mass flow controller, by time, and/or by a manual
application. Optionally, the valves 20, 30A and valves of the
injection assembly 16A may be manually opened and closed by a
user.
[0104] In the embodiment illustrated in FIG. 2, the injection
assembly 16A has been interconnected by piping 6A to a plurality of
injectors 17 of a material container 33, or "pig," with an interior
chamber for storing concrete materials. The injectors 17 have
outlets directed inward or facing the interior chamber of the
material container. Inlets of the injectors 17 are positioned on an
exterior surface of the material container. Each of the plurality
of injectors 17 has a valve that may be actuated to individually
control the flow of CO2 through the injector 17. The controller is
operable to send a signal to each of the plurality of injectors 17
to open or close the valve of the injector 17 and to increase or
decrease the flow of CO2 through each of the injectors 17. The
chamber of the storage container has an aperture that is open. By
opening one or more valves 20, 30, 30A, a supply of carbon dioxide
is applied through the injectors 17 to the interior of the material
container 33, treating the concrete materials in the material
container 33 with CO2 in accordance one embodiment of the present
invention. In yet another embodiment, liquid CO2 is applied to the
concrete materials in the material container 33. Optionally, a
closure may be interconnected to material container to seal the
aperture to prevent the CO2 injected into the material container
from escaping. In one embodiment, the chamber may be pressurized
after the aperture is sealed by the closure.
[0105] Referring now to FIGS. 3 and 4, a system 34 and a method 70
according to one particular embodiment are illustrated. While a
general order of the steps of the method 70 are shown in FIG. 4,
the method 70 can include more or fewer steps or the order of the
steps may be arranged differently than the method 70 illustrated in
FIG. 4 and described herein.
[0106] The method 70 starts 72 when a desired amount of carbon
dioxide 36 to be delivered to the mixer 8A is entered 74 into a
system controller 42. The set point can be a weight or mass of CO2.
The set point may be selected from a list of predetermined mixtures
based on design specifications for the concrete being produced
which may be displayed in a user interface 48 in communication with
the system controller 42. Alternatively, a custom amount of carbon
dioxide to be delivered to the mixer 8A may be entered into the
controller 42 by a user through the user interface 48. The user
interface 48 may be generated by a portable electronic device 50
physically separated from the system controller 42. Examples of
electronic devices 50 include smartphones, tablet devices, laptop
computers, other portable computers, or other devices running
software or an application (or "an app") adapted to interact with
the system controller 42 and capable of communicating with the
system controller 42 over either a wired 52 or a wireless 54
network. The electronic device 50 may generate the user interface
48 to enable a user, such as a cement truck operator, to access the
system controller 42 to control the system 34 and method 70. In one
embodiment, the user may access, receive information from, and
control the system controller 42 and the sensor array and
controlled devices in signal communication therewith by using an
electronic device 50 to communicate with the system controller 42
over an internet connection.
[0107] After the set point for the desired amount of CO2 to be
added to the concrete mix is entered 74 into the system controller
42, the system controller 42 determines 76 if there is a sufficient
amount of carbon dioxide in the storage container 4B. Load cells 38
are affixed to the storage container 4B and constantly monitor the
combined weight of the storage container 4B and liquid carbon
dioxide 36 and gaseous carbon dioxide 60 contained therein. The
combined weight of the storage container 4B and carbon dioxide
therein are continuously transmitted by the connection 40 to the
system controller 42. By subtracting the known empty weight of the
container 4B from the combined weight of the container 4B and the
carbon dioxide therein, the controller can determine the weight of
CO2 in the storage container 4B. If the system controller 42
determines 76 an insufficient amount of carbon dioxide 36 is
available, the method 70 returns until a sufficient amount of
carbon dioxide is available in the storage container 4B. If the
system controller 42 determines 76 there is a sufficient amount of
carbon dioxide available, the method 70 continues to 78 and the
system controller 42 sends a signal by connection 40 to start the
mixer 8A.
[0108] A mixing chamber of the mixer 8A is filled 80 with concrete
materials 44 (such as, for example rock, sand, other aggregates,
water, other cementitious materials, admixtures, and cement) per
the desired mix design and mixing continues. In one embodiment,
sensors in communication with the system controller 42 are operable
to measure the weight or volume of the concrete materials 44 to be
added to the concrete mix. The system controller 42 is further
operable to control conveyors, belts, pipes, or valves required to
transport the concrete materials 44 to be added to the concrete mix
to the mixing chamber of the mixer 8A.
[0109] Those of skill in the art will recognize that various
concrete materials 44 and admixtures may be added to the concrete
mixer 8A as required by design considerations based on the use and
desired characteristics of the concrete. Concrete materials 44
including, but not limited to, plastic, polymer concrete, dyes,
pigments, chemical and/or mineral admixtures, or similar materials
that may be represented in a variety of types and composition mixes
having various combinations of ingredients may be added to the
mixer 8A. When combined in the mixer 8A, the selected concrete
materials 44 create a concrete with desired characteristics. The
Applicant has found that the addition of water reducers and/or air
entrainment agents to the concrete materials 44 in the mixer 8A is
advantageous. Water reducers suitable for use in the present
invention include, by way of example only, Pozzolith.RTM. 200 N
water-reducing admixture, Pozzolith.RTM. 322 N water-reducing
admixture, and Glenium.RTM. 3400 NV high-range water-reducing
admixture, which are each produced by BASF. One example of a
suitable air entrainment agent is BASF's MB-AE.TM. 90
air-entraining admixture. It shall be understood that other water
reducers, air entrainment agents, and admixtures may be used with
the method and apparatus of the current invention and are within
the scope and spirit of the present invention as will be recognized
by one of ordinary skill in the art.
[0110] The position of an injection assembly 16B or snow horn
relative to the mixer 8A is monitored by sensors 46 and transmitted
by connection 40 to the system controller 42. The sensors 46 may
comprise optical, linear, or angular position sensors that, among
other things, track the relative and/or absolute positions of the
various movable components of the injection assembly 16B and the
mixer 8A and the alignment of stationary and moveable components.
The injection assembly 16B, mixer 8A, and sensors 46 may be moved,
positioned, and pointed by the system controller 42. When the
system controller 42 determines 82 that the injection assembly 16B
is in an appropriate position relative to the mixer 8A, the process
70 continues and the user may initiate 84 the delivery of carbon
dioxide by pressing a "start" button or other button on the user
interface 48. The system controller 42 then sends a signal by
connection 40 to open a control valve 56. The valve 56 opens 86 and
liquid 36 carbon dioxide leaves 88 the storage container 4B by
delivery piping 6.
[0111] The inventors have found that the efficiency of the system
34 is improved when substantially all of the CO2 transmitted to the
injection assembly 16B is in a liquid 36 state. The piping 6 and
other components of the system 34 are designed to operate at
temperatures and pressures required to maintain the CO2 in a liquid
36 state once it leaves the storage container 4B. Additionally,
positioning the CO2 storage container 4B as close as possible to
the injection assembly 16B reduces the amount of liquid carbon
dioxide 36 that changes phase to a gaseous 60 state.
[0112] To further increase the ratio of liquid 36 CO2 compared to
gaseous 60 CO2, the system 34 includes a liquid-gas separator 58 to
separate 90 the gaseous carbon dioxide 60 from the liquid carbon
dioxide 36. The gaseous carbon dioxide 60 is returned to the
storage container 4B by additional piping 6C interconnected to a
return valve 56A of the liquid-gas separator and the storage
container. Optionally, the gaseous carbon dioxide 60 may be vented
into the atmosphere through a release valve or vent. In one
embodiment, the liquid-gas separator 58 includes a valve 56A with a
first position to vent the gaseous carbon dioxide 60 to the
atmosphere. The valve 56A has a second position to return the
gaseous carbon dioxide 60 to the storage container 4b through the
additional piping 6C. The liquid-gas separator 58 and the valve 56A
are in signal communication 40 with the system controller 42 and
the system controller 42 is operable to control the valve 56A.
[0113] The percentage of liquid carbon dioxide 36 present in the
piping 6 can also be increased by designing the storage container
4B to retain the gaseous carbon dioxide 60. In one embodiment, the
piping 6 is interconnected to a lower surface of the storage
container 4B to extract only liquid carbon dioxide 36 from the
storage container 4b leaving the gaseous carbon dioxide 60 in the
head space of the storage container. In a preferred embodiment, the
piping 6 is interconnected to the bottom of the storage container
4B. In addition, the system 34 may include a liquid CO2 sensor 59
adapted to determine if liquid carbon dioxide 36 is in proximity to
the control valve 56 and can send information collected by the
sensor 59 to the system controller 42 by connection 40. The liquid
CO2 sensor 59 is further operable to transmit a signal to the
system controller 42 when gaseous carbon dioxide 60 is in contact
with the piping 6 or the control valve 56. The liquid CO2 sensor 59
can be positioned proximate to the control valve 56. In one
embodiment, a liquid CO2 sensor 59 is positioned inside the storage
container 4B.
[0114] Optionally, the liquid-gas separator 58 may also include a
mass flow controller. The combined separation instrument and mass
flow controller continuously monitors the mass of the gaseous
carbon dioxide 60 separated and the mass of the liquid carbon
dioxide 36 that passes through the separation instrument 58 and
transmits these masses to the system controller 42 by connection
40. The system controller 42 may optionally use the information
transmitted from the mass flow controller to determine when the
pre-set amount of CO2 has been delivered and then send a signal to
close the control valve 56.
[0115] After passing through the separator 58, the liquid carbon
dioxide 36 continues through the piping 6 and enters 92 an inlet 62
of the injection assembly 16B. The pressure differential from the
inlet 62 of the injection assembly 16B to the outlet 64 of the
injection assembly 16B causes the carbon dioxide to change state 94
from a liquid 36 to a gas 60 and from a liquid 36 to a solid 66 so
that the CO2 ejected from the outlet 64 of the injection assembly
16B is a mixture of solid carbon dioxide 66 snow and gaseous carbon
dioxide 60. The pressure differential also causes the temperature
of the CO2 to decrease. In one embodiment, the pressure
differential causes the temperature of the CO2 to decrease to no
more than -109.degree. F. In another embodiment, the temperature of
the CO2 decreases to less than -109.degree. F. The mixture of solid
66 and gaseous 60 carbon dioxide is discharged 96 into the mixer
8A.
[0116] According to a preferred embodiment of the present
invention, the concrete 68 is mixed in a CO2 atmosphere created by
flooding the mixing chamber of the mixer 8A with CO2. The mixing
chamber may have an open aperture. In some embodiments of the
present invention, a closure adapted to seal the aperture may be
interconnected to the mixer 8A. The mixing chamber of the mixer 8A
contains air which has been intentionally enriched with CO2.
According to this embodiment, substantially all the air in the
mixing chamber is replaced with gaseous CO2.
[0117] It is one aspect of embodiments of the present invention to
mix the concrete 68 and CO2 in a mixer 8A with a mixing chamber
that has an aperture that can be sealed with a closure. The mixing
chamber is loaded with concrete materials 44 (such as rock, sand,
aggregates, water, cement, and/or materials and admixtures) and CO2
according to a predetermined mix design as described above.
Optionally, the CO2 may be added to the mixing chamber of the mixer
8A in a liquid state 36. The aperture of the mixing chamber is then
sealed by the closure and the mixer 8A started. Optionally, in one
embodiment, the CO2 may be injected into the mixing chamber after
the mixing chamber is sealed by the closure. The sealed mixing
chamber of the mixer 8A may also be pressurized. Pressure sensors
within the mixing chamber transmit a pressure within the sealed
mixing chamber to the system controller by connection 40. The
system controller 42 can control the pressure within the sealed
mixing chamber by adding a predetermined amount of CO2 to the
mixing chamber. The controller 42 can also open one or more valves
interconnected to the mixing chamber to reduce the pressure within
the mixing chamber to keep the pressure at a predetermined amount
or to vent the pressure prior to opening the closure sealing the
aperture of the mixing chamber. Pressurized reactors that keep
materials sealed in a mixing chamber during a mixing process are
known to those of skill in the art. Mixing the concrete materials
44 and CO2 in a sealed mixing chamber results in almost all of the
CO2 being sequestered in the concrete 68 during the mixing process,
achieving a more complete reaction and greater saturation of CO2 in
the concrete materials 44.
[0118] In another embodiment, solid carbon dioxide 66 may be added
to the concrete materials 44 in a mixer 8 with either an open or
sealed mixing chamber. In this embodiment, the solid carbon dioxide
66 will react with and sublimate into the concrete 68 during the
mixing of the concrete materials 44. The system may also comprise a
slinger/crusher for use with solid carbon dioxide 66 blocks or dry
ice. Regular water ice in block form may be added to the concrete
mix in place of mix water for the purposes of hydrating and cooling
the mix simultaneously. Equipment known in the industry which is
used for grinding up water ice blocks and adding the ground ice
into the concrete mix in the mixer 8 can be modified to accept
solid carbon dioxide 66 blocks for addition to the concrete mix.
Using solid carbon dioxide 66 both treats the concrete mix with CO2
and cools the concrete mix.
[0119] The system controller 42 continuously monitors the load
cells 38 and optionally the mass information transmitted from the
optional mass flow controller to determine 98 the amount by weight
or mass of carbon dioxide 36 that has left the storage container
4B. When the system controller 42 determines 98 that the desired or
set amount of carbon dioxide 36 has been delivered, the system
controller 42 sends a signal by connection 40 to close the control
valve 56. The control valve 56 closes 100 and the flow of carbon
dioxide from the storage container 4B stops. Optionally, the system
controller 42 can control the amount of CO2 delivered to the mixer
8A by sending a signal to close the control valve 56 a
predetermined amount of time after the control valve 56 was opened.
The system controller 42 is also operable to control the rate of
CO2 delivered to the mixer 8A by sending a signal to the control
valve 56 to increase or decrease the flow of CO2 through the
control valve 56.
[0120] The gaseous 60 and solid 66 CO2 in the mixer 8A mixes 98 and
chemically reacts with the concrete materials 44 to change the
physical properties of the concrete. The mixer 8A continues to mix
the fresh concrete and CO2 until the system controller 42
determines 102 the concrete is thoroughly mixed and that the
chemical reaction of the CO2 is complete. The freshly mixed
concrete 68 is discharged 104 from the mixer 8A and the method 70
ends 106. The system controller 42 can send a signal to the mixer
8A causing the mixer 8A to discharge the mixed concrete and to stop
the mixer. The method 70 may repeat to produce subsequent batches
of concrete 68. The system 34 can be scaled to deliver small or
large batches of concrete treated with CO2. For example, in one
embodiment the system 34 can produce approximately 1,000 cubic
yards of concrete per day. However, this is just one example and
those of skill in the art will understand that they system 34 can
be designed to produce a larger or a smaller amount of concrete
each day.
[0121] It is expressly understood in making the foregoing
disclosure of this preferred embodiment that other steps may be
included, or certain steps omitted in the process, and that the
steps do not necessarily have to occur in this precise order to
accomplish the benefits described herein.
[0122] In all embodiments of the present invention, liquid 36,
gaseous 60, and/or solid 66 CO2 may also be injected or applied
directly to concrete materials 44 prior to mixing the concrete
materials 44 in the mixer 8. Sand, rock, and other fine or coarse
aggregates may be treated by injecting CO2 into aggregate
stockpiles, infusing the aggregates with CO2, storing the
aggregates in an enriched CO2 atmosphere (for example a sealed
chamber or storage tank containing gaseous, liquid, and/or solid
CO2), or soaking the aggregates in a CO2-rich medium such as
carbonated water. Cement may be treated with CO2 by altering the
production process of cement to increase the amount of CO2 retained
in the final product, by injecting CO2 into a cement storage vessel
or "pig," or by storing cement in an enriched CO2 atmosphere. In
one embodiment, the cement production process may be altered to
reduce the amount of CO2 driven off in the process of making cement
or by adding CO2 in the process to enrich the cement.
[0123] Other cementitious materials used for concrete production,
such as fly ash, pozzolan, or ground granulated blast furnace slag
(GGBFS), can also be treated with CO2 prior to being added to a
mixer 8 in a manner similar to those discussed above. For example,
CO2 may be injected into or added to the other cementitious
materials while they are in storage by storing the cementitious
material in an enriched CO2 atmosphere. Alternatively, the
production process of the cementitious material may be altered to
increase the amount of CO2 retained in the final product, for
example, by adding CO2 in the process to enrich the cementitious
material.
[0124] Water used in the production of the concrete may also be
used as a transport mechanism to add CO2 to the concrete 68 and/or
concrete materials 44. CO2 may be injected into the mix water to
measurably increase the CO2 content of the water. Carbonated mix
water may also be used in the production of concrete 68 according
to embodiments of the present invention. The water may be naturally
occurring carbonated water or may be processed carbonated water
enriched with carbon dioxide directly or indirectly. Any method of
treating or processing water which increases the level of CO2 for
mix water may be used with embodiments of the present invention. In
one embodiment, effluent water from a direct hydrocarbon fired
heater is used to add CO2 to the concrete mix.
[0125] Concrete additives and/or admixtures may also be used to add
CO2 to the concrete materials 44 and/or the concrete mix. For
example, concrete additives or compounds which contain CO2, or act
to release CO2 into the concrete mix or promote reaction of CO2
with the concrete mix may be added to the concrete and/or concrete
materials 44. A predetermined amount of concrete additives or
compounds can be added to the concrete mix to add a desired amount
of CO2 to the concrete 68 based on design characteristics of the
concrete 68.
[0126] Referring now to FIG. 5, a system controller 42 for use with
various embodiments of the present invention is illustrated. The
system controller 42 includes a computer 110. The computer 110 may
be a general purpose personal computer (including, merely by way of
example, personal computers and/or laptop computers running various
versions of Microsoft Corp.'s Windows.TM. and/or Apple Corp.'s
Macintosh.TM. operating systems) and/or a workstation computer
running any of a variety of commercially-available UNIX.TM. or
UNIX-like operating systems. The computer 110 may also have any of
a variety of applications, including for example, database client
and/or server applications, and web browser applications.
Alternatively, the computer 110 may be any other electronic device,
such as a thin-client computer, laptop, Internet-enabled mobile
telephone or smartphone, and/or tablet computer.
[0127] The computer 110 is in signal communication via connections
40 with a sensor array 112 and controlled devices 114. The computer
110 may receive and process information from components of the
sensor array 112 and the controlled devices 114. The sensor array
112 includes the liquid/gas sensing instrument 12, mass flow
controller 32, load cells 38, position sensors 46, liquid CO2
sensor 59, and other sensors including pressure sensors, flow rate
sensors, thermometers, moisture indicators, timers, etc. Controlled
devices 114 are any devices having an operation or feature
controlled by the computer 110 including the mixers 8, tank
isolation valve 10, liquid/gas sensing valve 12, automated
injection valve 14, the injection assembly 16, injectors 17, system
shut-off valves 20, pressure reducing valves 22, gas purifiers 24,
valves 30, mass flow controllers 32, sensors 46, control valve 56,
valve 56A, and the liquid-gas separator 58. Controlled devices also
include conveyors, belts, pipes, or valves that transport the
concrete materials to the mixer and load the concrete materials
into the mixer. The computer 110 generates signals to actuate or
control the controlled devices 114. The computer 110 generally
comprises a software-controlled device that includes, in memory
116, a number of modules executable by one or more processors 118.
The executable modules include a controller 120 to receive and
process signals from the sensor array 112 and generate and transmit
appropriate commands to the controlled device 114.
[0128] A user interacts with the control system 42 through any
means known to those skilled in the art, including a display 122
and an input device 124 such as a keyboard, mouse, or other
pointer, and/or gestures captured through gesture capture sensors
or surfaces, such as a touch sensitive display on a handheld or
portable device 50. The term "computer-readable medium" as used
herein refers to any tangible storage and/or transmission medium
that participates in providing instructions to a processor for
execution. Such a medium may take many forms, including but not
limited to, non-volatile media, volatile media, and transmission
media. Non-volatile media includes, for example, NVRAM, or magnetic
or optical disks. Volatile media includes dynamic memory, such as
main memory. Common forms of computer-readable media include, for
example, a floppy disk, a flexible disk, hard disk, magnetic tape,
or any other magnetic medium, magneto-optical medium, a CD-ROM, any
other optical medium, punch cards, paper tape, any other physical
medium with patterns of holes, a RAM, a PROM, and EPROM, a
FLASH-EPROM, a solid state medium like a memory card, any other
memory chip or cartridge, a carrier wave as described hereinafter,
or any other medium from which a computer can read. A digital file
attachment to e-mail or other self-contained information archive or
set of archives is considered a distribution medium equivalent to a
tangible storage medium. When the computer-readable media is
configured as a database, it is to be understood that the database
may be any type of database, such as relational, hierarchical,
object-oriented, and/or the like. Accordingly, the disclosure is
considered to include a tangible storage medium or distribution
medium and prior art-recognized equivalents and successor media, in
which the software implementations of the present disclosure are
stored.
[0129] While various embodiments of the present disclosure have
been described in detail, it is apparent that modifications and
alterations of those embodiments will occur to those skilled in the
art. However, it is to be expressly understood that such
modifications and alterations are within the scope and spirit of
the present disclosure, as set forth in the following claims.
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