SYSTEM AND METHOD FOR DISPOSING CARBON DIOXIDE
20170341988 · 2017-11-30
Assignee
Inventors
Cpc classification
C04B18/02
CHEMISTRY; METALLURGY
C04B38/103
CHEMISTRY; METALLURGY
C04B2111/00017
CHEMISTRY; METALLURGY
C04B2111/28
CHEMISTRY; METALLURGY
C04B38/103
CHEMISTRY; METALLURGY
International classification
C04B38/10
CHEMISTRY; METALLURGY
C04B18/02
CHEMISTRY; METALLURGY
Abstract
A system and method for disposing carbon dioxide is disclosed. The system includes a foam generator that generates a plurality of disposable foam vessels from a polymer based solution mixed with water and captured carbon dioxide from the atmosphere. The plurality of disposable foam vessels contains an amount of carbon dioxide. The plurality of disposable foam vessels is mixed in a cementitious material with a set of mixers. In a preferred embodiment, the set of mixers is a concrete mixing plant. During the curing process of the cementitious material the plurality of disposable foam vessels dissipates allowing for a timely release of CO.sub.2 to chemically react with the surrounding cementitious material. This irreversible chemistry change permanently disposes of the carbon dioxide.
Claims
1. A system for disposing carbon dioxide, comprising: a foam generator; a carbon dioxide source connected to the foam generator, supplying carbon dioxide to the foam generator; a water source connected to the foam generator, supplying water to the foam generator; a gas entrainment solution source connected to the foam generator, supplying a gas entrainment solution to the foam generator; and, a set of disposable foam vessels generated from the carbon dioxide, the water, and the gas entrainment solution.
2. The system of claim 1, wherein the carbon dioxide has a gas pressure range from approximately 60 pounds per square inch to approximately 150 pounds per square inch.
3. The system of claim 1, wherein the carbon dioxide has a gas flow rate range from approximately 2 cubic feet per minute to approximately 50 cubic feet per minute.
4. The system of claim 1, wherein the water has a water temperature range from approximately 35 degrees Fahrenheit to approximately 100 degrees Fahrenheit.
5. The system of claim 1, wherein the water has a water flow rate range from approximately 0.02 gallons per minute to approximately 10 gallons per minute.
6. The system of claim 1, wherein the gas entrainment solution has a solution flow rate range from approximately 0.02 gallons per minute to approximately 10 gallons per minute.
7. The system of claim 1, wherein the gas entrainment solution is a polymer based solution.
8. The system of claim 1, wherein the gas entrainment solution, by weight, comprises: approximately 96.8% to approximately 82.0% of water; approximately 0.04% to approximately 3.0% of n-dodecyl-b-iminodipropionic acid; approximately 0.08% to approximately 5.0% of n,n-bis(2-hydroxyethyl) dodecanamide; and, approximately 2.0% to approximately 10.0% of an oligomer of ethelene oxide.
9. A medium for disposing carbon dioxide, comprising: a cementitious mixture comprising: from approximately 2% by volume of the cementitious mixture to approximately 80% by volume of the cementitious mixture of a plurality of disposable foam vessels, comprising: water; a gas entrainment solution; and, carbon dioxide.
10. The medium of claim 9, wherein the cementitious mixture is a concrete mixture.
11. The medium of claim 10, wherein the concrete mixture further comprises: Portland cement; water; aggregate; and, sand.
12. The medium of claim 10, wherein the concrete mixture further comprises a high range water reducer.
13. The medium of claim 9, wherein the gas entrainment solution, by weight, comprises: approximately 96.8% to approximately 82.0% of water; approximately 0.04% to approximately 3.0% of n-dodecyl-b-iminodipropionic acid; approximately 0.08% to approximately 5.0% of n,n-bis(2-hydroxyethyl) dodecanamide; and, approximately 2.0% to approximately 10.0% of an oligomer of ethylene oxide.
14. A method for disposing carbon dioxide comprising the steps of: providing carbon dioxide at a predetermined gas pressure and a predetermined gas flow rate; providing water at a predetermined water temperature and a predetermined water flow rate; providing a gas entrainment solution at a predetermined solution flow rate; generating a plurality of disposable foam vessels from the carbon dioxide, the water, and the gas entrainment solution; mixing the plurality of disposable foam vessels with a cementitious material to generate a cementitious mixture; and, dissipating the plurality of disposable foam vessels in the cementitious mixture.
15. The method of claim 14, wherein the step of providing a gas entrainment solution at a predetermined solution flow rate further comprises the step of providing a polymer based solution as the gas entrainment solution.
16. The method of claim 14, wherein the step of providing a gas entrainment solution at a predetermined solution flow rate further comprises the steps of: providing from approximately 96.8% to approximately 82.0% of water for the gas entrainment solution; providing from approximately 0.04% to approximately 3.0% of n-dodecyl-b-iminodipropionic acid for the gas entrainment solution; providing from approximately 0.08% to approximately 5.0% of n,n-bis(2-hydroxyethyl) dodecanamide for the gas entrainment solution; and, providing from approximately 2.0% to approximately 10.0% of an oligomer of ethylene oxide of an oligomer of ethelene oxide for the gas entrainment solution.
17. The method of claim 14, wherein the step of mixing the plurality of disposable foam vessels with a cementitious material to generate a cementitious mixture further comprises the steps of: providing Portland cement for the cementitious mixture; providing water for the cementitious mixture; providing aggregate for the cementitious mixture; and, providing sand for the cementitious mixture.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The embodiments disclosed below will described with reference to the following drawings.
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DETAILED DESCRIPTION
[0031] Referring to
[0032] In a preferred embodiment, no minimum percentage of carbon dioxide is required. The carbon dioxide can be mixed with other gases such as compressed air or nitrogen.
[0033] In a preferred embodiment, foam generator 102 is the Miracon® ToughAir® Air Entrainment System available from Miracon Technologies, LLC of Richardson, Tex. Any foam generator known in the art may be employed.
[0034] In a preferred embodiment, gas entrainment solution 119 is a polymer based solution. Any type of air entrainment solution known in the art may be employed.
[0035] An exemplary formula for the gas entrainment solution is provided in Table 1 below.
TABLE-US-00001 TABLE 1 Amount Ranges (in approximate Molecular percentage Component Formula by weight) Water H.sub.2O 91.3% to 82.0% N-Dodecyl-B- C.sub.18H.sub.33NNa.sub.2O.sub.4 0.04% to 3.0% Iminodipropionic Acid N,N-BIS(2-HYDROXY- C.sub.16H.sub.33NO.sub.3 0.08% to 5.0% ETHYL)DODECANAMIDE Oligomer of Ethylene Oxide C.sub.2nH.sub.4n+2O.sub.n+1 2.0% to 10.0%
[0036] In some embodiments, additives may be added to the water supply and/or gas entrainment solution 119 to alter the structure of the plurality of disposable foam vessels.
[0037] Referring to
[0038] In a preferred embodiment, air entrainment system 100 is housed in station 104 of concrete plant 103. Concrete plant 103 includes hoppers 105, 106, and 107. Hopper 105 is connected to gate 108. Gate 108 is connected to chute 111. Hopper 106 is connected to gate 109. Gate 109 is connected to chute 112. Hopper 107 is connected to gate 110. Gate 110 is connected to chute 113. Each of chutes 111, 112, and 113 is connected to outlet 114. A set of controllers is connected to each of gates 108, 109, and 110. Hoppers 105, 106, and 107 store materials such as cement, sand, rock and other aggregates, and supplemental cementitious materials, such as fly ash. Predetermined amounts of materials, including water, are controllably fed into mixer 116 of concrete truck 117. The generated plurality of disposable foam vessels is controllably sent through outlet 115 to mixer 116 to be mixed with the concrete.
[0039] In a preferred embodiment, the plurality of disposable foam vessels is mixed with the concrete as a foam in an amount ranging from approximately 2% to approximately 80% by volume of the entire concrete mix. The percentage by volume depends on the application of the concrete and the desired properties of the final concrete product. In some embodiments, the percentage of volume substitution by the plurality of disposable foam vessels is as much as approximately 80% by volume where the plurality of disposable foam vessels replaces other materials. For example, at approximately 80% by volume of the plurality of disposable foam vessels, the only remaining materials in the concrete mix would be cement and water. It will be appreciated by those skilled in the art that the extent, number, and combinations of suitable mix designs that may be employed are numerous.
[0040] It will be further appreciated by those skilled that numerous materials known in the art that can be added into a concrete mixture include without limitation: different types of cementitious materials including different types of cement, fly ash, slag; different types of rock materials including hard and/or dense rock, many different types of lightweight aggregate, or no rock or aggregate at all; different types of sand including find sands to coarse sands; and any admixtures and/or combinations of admixtures known in the art and any suitable range amounts of such admixtures and/or combinations of admixtures known in the art may be employed.
[0041] An exemplary concrete mix design is described in Table 2 below, which can be scaled to suit any desired need. Other suitable mix designs known in the art may employed.
TABLE-US-00002 TABLE 2 Amount (approximate percentage Component by volume) Portland Cement - Type I/II 11.1% Water 15.2% #67 Rock 34.0% Concrete Sand 31.3% Gas Entrainment (Foam vessels) 7.9% High Range Water Reducer (preferably, Master 0.01% Builders MB7500, although any suitable high range water reducer known in the art may be employed)
[0042] In other embodiments, a pre-cast concrete plant is employed. Any mechanism known in the art to mix the plurality of disposable foam vessels with concrete may be employed.
[0043] In a preferred embodiment, the plurality of disposable foam vessels is used with existing mix designs, products and infrastructure, including mix designs for precast and transit mixtures—to be cast in place.
[0044] In a preferred embodiment, the plurality of disposable foam vessels is designed to dispose of carbon dioxide in any wet cast concrete application, with a polymer based air entrainment solution. As will be further described below, the controlled release of carbon dioxide into wet cast concrete enables the carbon dioxide to be consumed in the chemical reaction. The cement acts as a natural sink for the carbon dioxide. The carbon dioxide is compartmentalized, engages in the chemistry of the curing concrete mix, and permanently becomes part of the final product. As the carbon dioxide is released in a controlled, timely manner, the carbon dioxide is converted to calcium carbonate, resulting in enhanced properties of the concrete.
[0045] The disclosed embodiments allow for supplemental cementitious materials to be used as partial replacements of quantities of Portland cement which results lower amounts of Portland cement required. Supplemental cementitious materials have a calcium based chemistry similar to that of Portland cement. The reduction in the use of Portland cement lowers the carbon footprint of concrete. Applications of the disclosed embodiments range from bridge decks, buildings, playground materials, and soil stabilization.
[0046] Referring to
[0047] Referring to
[0048] Referring to
[0049] Referring to
[0050] At step 503, a gas entrainment solution is maintained at a predetermined flow rate. In a preferred embodiment, the predetermined flow rate is in a range from approximately 0.02 gpm to approximately 10 gpm. In this step, any mechanisms known in the art of increasing and/or decreasing liquid flow rates may be employed, including pumps, valves, and/or piping of varying diameters.
[0051] At step 504, a plurality of disposable foam vessels is generated from the water, the carbon dioxide, and the gas entrainment solution.
[0052] At step 505, the plurality of disposable foam vessels is mixed with a cementitious material in a plastic state, preferably in a plastic concrete mixture. At step 506, the carbon dioxide reacts with the cementitious material in the concrete mixture after a predetermined time. In a preferred embodiment, the predetermined time is the time period required for the plurality of disposable foam vessels to dissipate. Other known means of delaying dissipation of the foam vessels or bubbles may be employed, including chemical additives to the cementitious material and/or the gas entrainment solution.
[0053] Tests Overview
[0054] A set of tests were performed to evaluate the efficacy of the disclosed embodiments. The tests included the fabrication of concrete specifications containing average loadings of carbon dioxide, 13.8% (Lo CO.sub.2) and 18.1% (Hi CO.sub.2) by volume, introduced into the concrete specimens utilizing the previously described disposable foam vessels, and a control average loading of 11% by volume of compressed laboratory air (Comp. Air). Each concrete specimen was fabricated using the same foaming agent and foam generator supplied by Miracon Technologies, LLC of Richardson, Tex.
[0055] The testing program characterized the physical and mechanical properties of the fabricated, cured concrete specimens. The specimens were evaluated petrographically to assess the impact of carbon dioxide addition into the concrete mixtures, and then compared to the control mixture made with compressed air. Observations were made as to desired properties, including mechanical strength, freeze-thaw resistance and drying shrinkage.
[0056] Test 1—Mechanical and Physical Evaluation
[0057] The properties of interest selected for this evaluation were mechanical (compressive) strength, freeze-thaw resistance, and length change. The selected properties were evaluated for Comp. Air, Hi CO.sub.2 and Lo CO.sub.2 over a sufficient period of time to study the early and short term effects of concrete carbonization on specimen durability.
[0058] The purpose of the Hi CO.sub.2 (18.1%) test was to determine if significantly higher carbon dioxide loading rates had any recordable effect on early or later stage curing rates or if higher loading rates of carbon dioxide would produce a greater possibility or incidence of development of carbonic acid.
[0059] Generally, the results show that there was no recordable difference in rate of cure, nor was there any evidence of carbonic acid in the petrographic macro or microscopic analysis. The results of Test 1—Mechanical and Physical Evaluation of industry accepted test are shown below in Table 3, Table 4, and Table 5.
TABLE-US-00003 TABLE 3 ASTM C666, Standard Test Method for Resistance of Concrete to Rapid Freezing and Thawing Procedure A, Freezing and Thawing in Water (306 cycles) Average Comp. Average Lo Average Hi Air (11%) CO.sub.2 (13.8%) CO.sub.2 (18.1%) Length Change % 0.012 0.013 0.012
TABLE-US-00004 TABLE 4 ASTM C 157 Drying Shrinkage Average Comp. Average Lo Average Hi Air (11%) CO.sub.2 (13.8%) CO.sub.2 (18.1%) Drying Shrinkage −0.044 −0.038 −0.015
[0060] Referring to Table 4, a negative length change indicates shrinkage. Accordingly, a higher/greater negative number indicates a greater length change.
TABLE-US-00005 TABLE 5 ASTM C39 and AASHTO T 22 Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens (psi) Average Comp. Average Lo Average Hi Time Air (11%) CO.sub.2 (13.8%) CO.sub.2 (18.1%) 7 Days 4650 4077 2160 28 Days 5277 4603 2440 90 Days 5777 4993 2830
[0061] An accepted concrete industry practice is that compressive strength will decrease by 5% to 6% for every 1% increase in air/gas. This practice applies to products of relatively close air void density. For example, where Average Comp-Air is 11% and Average Lo CO.sub.2 is 13.8%, the industry accepted compressive strength decrease is calculated as follows:
Compressive Strength.sub.Industry=(13.8%−11%)*5% Eq. 1
Compressive Strength.sub.Industry=14%
Now, using the test samples, the tested compressive strength reduction is as follows:
[0062] As can be seen by comparing the results of Eq. 1 and Eq. 2, the Average Lo CO.sub.2 compressive strength is at least within the industry accepted compressive strength decrease.
[0063] Test 2—Petrographic Study of Concrete Specimens
[0064] Each of the three concrete samples was microscopically evaluated to observe if any of the microstructures of the tested samples were affected by the addition of carbon dioxide. A thin section from each concrete specimen was prepared for examination with an optical microscope. The micrographs of the void system of the compressed air sample, the Lo CO.sub.2 sample, and the Hi CO.sub.2 samples are shown in
[0065] Referring to
[0066] Test 3—Carbonation of Concrete Paste
[0067] Referring to
[0068] Referring to
[0069] Referring to
[0070] Referring to
[0071] Test 4—Calculation of Internal Bubble Pressure for the Plurality of Foam Vessels
[0072] The test was performed using a custom-built cylindrical pressure chamber having an internal diameter of approximately 6.06 inches and a length of approximately 24 inches. The purpose of the test was to confirm the amount of pressure at which a foam vessel or bubble would collapse. The test methodology began by filling the pressure chamber from the top with foam. Ensure good quality foam is flowing through the chamber and out the exhaust port at the bottom of the chamber. Once the chamber is full of foam, the foam supply is shut off and the valve at the chamber closed. The exhaust port valve at the bottom of the chamber is closed. Utilizing a regulator to control the pressure level, slowly increase the pressure in the chamber and document when the foam collapses and what percentage of foam in the chamber collapses at the documented pressure. Continue to increase the pressure level, documenting all collapses of bubble that are in excess of 10% of the total chamber volume. When the maximum safe pressure is reached on the pressure chamber, document the remaining volume of foam left in the chamber. The weight of the gas contained in the chamber was then calculated.
[0073] Calculations were made to show the expected pressures at which the foam vessel or bubble would collapse and are shown in Table 6 below.
TABLE-US-00006 TABLE 6 Volumetric Calculations Based on Testing Pressure in Bottle 1st 2nd 3rd 4th Compressed When full Bubble Bubble Bubble Bubble Final Compressed Gas Atmospheric and valve Collapse Collapse Collapse Collapse Pressure Units Gas(Static) (Dynamic) Pressure is closed Pressure Pressure Pressure Pressure on Chamber PSI 80 70 14.7 11.6 30.5 34.5 38 42 60 Pa 101325 181304 311615 339194 363326 390905 515011 % of 20% 15% 15% 15% 35% Chamber
[0074] The assumptions listed in Table 7 below were utilized to calculate the weight of carbon dioxide in the foam vessel or bubble.
TABLE-US-00007 TABLE 7 Assumptions PSI to PA 6894.76 Pa/PSI Air at 1 atm 101325 Pa Volume of Chamber 693.4 in.sup.3 Volume of Chamber 0.401 ft.sup.3 Volume of Chamber 0.011 m.sup.3 R - Ideal Gas Constant 8.3145 J/mol K n - moles 28.97 air Molecular Weight of Air 28.97 gm/mol Molecular Weight of CO2 44.01 gm/mol Temp - Kelvin 293 K Temp - Celsius 20 C.
[0075] Under the Ideal Gas Law:
PV=nRT Eq. 3
n=PV/RT Eq. 4
where P is pressure in Pascals (Pa), V is volume (cubic meters (m.sup.3)), n is the amount of gas in moles, R is the Universal Gas constant (J/mol K), T is temperature in Kelvins (K).
[0076] Using Eq. 4, the weight of air at (20° C. and 1 atm) can be calculated as follows:
n=PV/RT Eq. 4
n=(101325 Pa*0.0113 m3)/(8.3145 J/mol K*293 K)
n=0.470 moles
Weight of Air=moles*molecular Weight Eq. 5
Weight of Air=13.6 gms
[0077] The weight of air in the pressure chamber as validated by bubble collapse requires calculation of n at each bubble collapse pressure using Eq. 4 and is shown in Table 8 below.
TABLE-US-00008 TABLE 8 Weight of Air in the Pressure Chamber as Validated by Bubble Collapse 1st 2nd 3rd 4th Bubble Bubble Bubble Bubble Final Collapse Collapse Collapse Collapse Pressure Units Pressure Pressure Pressure Pressure on Chamber PSI 30.5 34.5 38 42 60 Pa 311615 339194 363326 390905 515011 % of 20% 15% 15% 15% 35% Chamber n 1.45 1.57 1.69 1.81 2.39 Weight 8.37 6.84 7.32 7.88 24.22 (gm)
[0078] The total weight of air inside the foam is the sum of weights at the collapse pressures. The weight of air in the pressure chamber is approximately 54.64 gm. The weight of air at 20° C. and 1 atm (from Above) is 13.6 gm. Therefore, the bubble contains 4.01 times the weight of air.
[0079] Due to the fact that carbon dioxide can be considered an ideal gas, particularly at less than 5 atmospheres, the net weight of carbon dioxide can be calculated in the foam by substituting the molecular weight of the carbon dioxide. Therefore, the weight of carbon dioxide is as follows:
The weight of carbon dioxide in a cubic foot of foam is:
EXAMPLES
[0080] The disclosed embodiments may be deployed in any number of means, including the following examples. In these examples, the following definitions and calculations are used.
[0081] Conversions
1 yd.sup.3=27 ft.sup.3
1 MT (metric ton)=2200 lb
[0082] Carbon Dioxide Information
Weight.sub.CO.sub.
STP=0 Celcius and 1 atm
Weight.sub.Gas Entrained=0.46 lb/ft.sup.3
[0083] Cement and Concrete Information
[0084] The usage of Portland Cement in the USA in 2013 was 77 Million Metric Tons of cement. A conservative estimate of 50% of the above cement amount is used in infrastructure—roads, highways, bridges, sewers, and hospitals. 1 yd.sup.3 of concrete has an average of: 400 lbs. of cement. 1 yd.sup.3 of concrete weighs an average of 3800 lbs. Therefore, the volume of concrete used in the USA in 2013 is:
Concrete absorbs between 40-55% of initial carbon dioxide emissions over 100 year life. In 2013, world production of cement was 4080 million Metric Tons.
[0085] Gas Entrainment
[0086] Use of gas entrainment in concrete is critical for improved durability.
Example 1
Carbon Dioxide Disposal in High Strength Applications
[0087] In a high strength application, the disclosed embodiments may be deployed in infrastructure, such as roads and bridges. For example, infrastructure mix design criteria typically allows for approximately 6% air/gas entrainment. In an example at 6% gas entrainment in infrastructure where the total concrete used in the USA in 2013 is 494,098,000 yd.sup.3 and the concrete used in infrastructure in 2013: 247,049,000 yd.sup.3, the total potential weight of carbon dioxide use is:
[0088] In an example at 9% gas entrainment in infrastructure where the total concrete used in the USA in 2013 is 494,098,000 yd.sup.3 and the concrete used in infrastructure in 2013: 247,049,000 yd.sup.3, the total potential weight of carbon dioxide use is:
Example 2
High Volume Applications
[0089] Flowable Fill/Soil Stabilization, Fire Retardant and Insulating applications are currently utilized in areas such as high risk chemical plants. The use of foamed cement to cover building structural beams where very low thermal conductivity is a must, lends to concrete with low compressive strength (e.g. 3,000+ psi) and a great volume of air/gas for insulation properties. In a job size of 18,000 yd.sup.3 of flowable fill concrete at 40% gas entrainment, the amount of carbon dioxide used is:
The weight of carbon dioxide if used in this job would be:
Example 3
Beam Fireproofing
[0090] Referring to
[0091] At 35% gas entrainment, the volume of carbon dioxide is:
[0092] The weight of carbon dioxide per beam is:
Example 4
Carbon Dioxide Disposal Estimates
[0093] According to the PCA, the percentage of total cement usage in the United States is listed in Table 9 below.
TABLE-US-00009 TABLE 9 Estimates for Cement Yielding Potential CO.sub.2 Consumption for the USA Percentage of Total Cement used in the Volume USA 157,796,100 50% Infrastructure, 400 lb./yd.sup.3 @6% 71,008,245 15% Potential Infrastructure at 9% 94,677,660 15% Unregulated, agriculture, sewage - 12% gas entrainment 57,708,288 12% Residential, nonstructural, 350 lb./yd.sup.3 8% 92,047,725 5% CLSM, Nonstructural, flowable fill, shotcrete and other lightweight applications - 35% 55,228,635 3% Nonstructural, decorative, insulative -35% 528,466,653 lb. 0.53 billion lb. total potential CO.sub.2 consumption for USA
[0094] The above estimates translate to 159 million yd.sup.3 potential carbon dioxide consumption for United States. This would fill a 6 inch diameter pipeline around the world 167 times. This translates to: 4.2 billion ft3 of carbon dioxide consumption, which would fill 243 billion—½ liter bottles of water, five times the number consumed in the USA per year, 45,278 Tons of carbon dioxide consumption, which would cover 276 football fields ten feet deep.
[0095] Worldwide, the total cement usage is 4080 million metric tons. The total cement usage in the USA is 77 million metric tons. Utilization of the disclosed embodiments worldwide would have 53 times the impact on carbon dioxide being disposed of. At these rates, at 6% gas entrainment, 227 billion ft.sup.3 or 14 million tons of carbon dioxide is disposed.
[0096] It will be appreciated by those skilled in the art that modifications can be made to the embodiments disclosed and remain within the inventive concept. Therefore, this invention is not limited to the specific embodiments disclosed, but is intended to cover changes within the scope and spirit of the claims.