Abstract:
Processes are disclosed for managing the reduction of carbon dioxide emissions by a process of mining, acquiring water, capturing carbon and disposing of water containing bicarbonates. A number of process configurations of accelerated weathering of carbonate mineral-containing materials (AWC) reactors are disclosed.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims the benefits, under 35 U.S.C.§119(e), of U.S. Provisional Application Ser. No. 61/180,660 entitled “Method of Managing Carbon Dioxide Emissions”, filed May 22, 2009, which is incorporated herein by this reference. 
     
    
     FIELD 
       [0002]    The present invention relates generally to a method and means of managing the reduction of carbon dioxide emissions by a process of mining, acquiring water, capturing carbon and disposing of water containing calcium bicarbonates. 
       BACKGROUND 
       [0003]    Many industrial operations are powered by hydrocarbon fuels which generate flue gases that are comprised primarily of carbon dioxide, water vapor, sulphur dioxide and NOx emissions. The sulphur dioxide and NOx emissions may be reduced by well known pre- and post-combustion processes in which carbon dioxide is captured. Carbon dioxide emissions are typically not always removed from flue gases, although pre- and post-combustion methods for removing at least some of the carbon dioxide emissions are being implemented on many hydrocarbon powered industrial operations. 
         [0004]    Rau et al have proposed an accelerated weathering of limestone (“AWL”) process as an economical method of removing carbon dioxide from flue gases as described, for example, in “Reducing Energy-Related CO2 Emissions Using Accelerated Weathering of Limestone”, G. H. Rau, K. G. Knauss, W. H. Langer, K. Caldeira, Energy 32, 2007. In the AWL process, carbon dioxide is combined with crushed limestone in water to produce a calcium bicarbonate solution. This solution can be diluted with additional water and sequestered in the ocean. 
         [0005]    Rau proposes to use waste limestone fines from existing limestone mines and quarries for his AWL reactors. This limits the AWL technology to applications where limestone fines are available and requires AWL installations that are nearby to large sources of water to dilute the calcium bicarbonate solutions formed in AWL reactors to levels of alkalinity acceptable for disposal into these near by bodies of water. 
         [0006]    There remains a need for more general methods of applying the AWL process to hydrocarbon-powered industrial operations that may or may not be sited near large bodies of surface or underground water or near sources of limestone. 
       SUMMARY 
       [0007]    These and other needs are addressed by the various embodiments and configurations of the present invention which are directed generally to providing sources of large quantities of carbonate mineral-containing materials and methods of sequestering calcium bicarbonate solutions. 
         [0008]    In one embodiment, a method is provided that includes the steps of: 
         [0009]    (a) receiving, from a hydrocarbon-powered industrial operation, a carbon dioxide-containing off-gas; 
         [0010]    (b) contacting the off-gas with water and an underground supply of carbonate mineral-containing materials to convert at least a portion of the carbon dioxide and carbonate mineral-containing materials into aqueous bicarbonate and a treated off-gas; and 
         [0011]    (c) discharging the treated off-gas. 
         [0012]    In another embodiment, a system is provided that includes: 
         [0013]    (a) a supply of carbonate mineral-containing materials; 
         [0014]    (b) an inlet for a carbon dioxide-containing off-gas from a hydrocarbon-powered industrial operation, the hydrocarbon-powered industrial operation converting hydrocarbons into the off-gas; 
         [0015]    (c) an accelerated weathering of carbonate mineral-containing materials (“AWC”) reactor to contact the off-gas with water and carbonate mineral-containing materials to convert at least a portion of the carbon dioxide and carbonate mineral-containing materials into aqueous bicarbonates and a treated off-gas, the AWC reactor being positioned underground; and 
         [0016]    (d) an outlet to discharge the treated off-gas. 
         [0017]    In another embodiment, a reactor assembly is provided that includes: 
         [0018]    (a) a first zone to contact water with a carbon dioxide-containing off-gas to dissolve at least most of the carbon dioxide in the water to form a treated off-gas and an aqueous process stream comprising dissolved carbon dioxide in the form of carbonic acid, the first zone being substantially free of carbonate mineral-containing materials; and 
         [0019]    (b) a second zone to contact the process stream with carbonate mineral-containing materials to convert at least most of the carbonic acid to bicarbonates and form aqueous bicarbonates, wherein the first and second zones are spatially dislocated from one another. 
         [0020]    In another embodiment, a method is provided that includes the steps of: 
         [0021]    (a) in a first zone, contacting water with a carbon dioxide-containing off-gas to dissolve at least most of the carbon dioxide in the water to form a treated off-gas and an aqueous process stream comprising dissolved carbon dioxide in the form of carbonic acid, the first zone being substantially free of carbonate mineral-containing materials; and 
         [0022]    (b) in a second zone, contacting the process stream with carbonate mineral-containing materials to convert at least most of the carbonic acid to bicarbonates and form aqueous bicarbonates, wherein the first and second zones are spatially dislocated from one another. 
         [0023]    In one configuration, the AWC process is a two-step process by two reactors, one which dissolves off-gases in water and a second which converts dissolved carbon dioxide to calcium bicarbonate by the addition of crushed limestone and limestone fines. 
         [0024]    In yet another embodiment, a method is provided that includes the steps of: 
         [0025]    (a) at high tide, collecting seawater in at least a first excavation; 
         [0026]    (b) at low tide, removing the collected seawater from the at least a first excavation; 
         [0027]    (c) processing the seawater to form a discharge stream; and 
         [0028]    (d) at low tide, locating the discharge stream in the at least a first excavation, whereby, at high tide, the discharge stream is removed from the at least a first excavation. 
         [0029]    In another embodiment, a system is provided that includes: 
         [0030]    (a) at least a first underground excavation operable, at high tide, to collect seawater; and 
         [0031]    (b) a facility operable, at low tide, to remove the collected seawater from the at least a first excavation; process the seawater to form a discharge stream; and locate the discharge stream in the at least a first excavation, whereby, at high tide, the discharge stream is removed from the at least a first excavation. 
         [0032]    In one configuration, an AWC facility is sited underground, near an ocean, so that the action of the tides coming in and going out are used to move water into the AWL reactor facility and then dilute and flush out the resulting calcium bicarbonate solution. 
         [0033]    In one configuration, a carbonate (e.g., carbonate or dolomite) mine is sited near a hydrocarbon-powered industrial operation such as, for example, a power plant, a cement production plant, a steel production plant, or a thermal hydrocarbon recovery operation. The carbonate rock is used for several purposes such as supplying commercial aggregate, water softening, sulphur and carbon dioxide removal from the combustion of hydrocarbon fuels. Captured carbon dioxide can converted to bicarbonates (e.g., calcium bicarbonate) by an AWC reactor system and can be sequestered in a mined out section of the mine. In this configuration, large amounts of water required for diluting bicarbonate solutions formed in AWC reactors may be unnecessary as the underground reactor can use modest sources of local water or nearby aquifers to dilute, disperse and sequester the bicarbonates. 
         [0034]    In another configuration, a carbonate mine is sited near a hydrocarbon-powered industrial operation. Captured carbon dioxide is converted to bicarbonates using an AWC process in which the AWC reactor is sited in an excavated cavern where the carbon capture reaction takes place and the resulting bicarbonate solution is sequestered. A portion of the captured carbon dioxide may also be sequestered in a mined out section of the limestone mine. In this configuration, large amounts of water required for diluting bicarbonate solutions formed in AWC reactors may not be necessary as the underground reactor can use modest sources of local water or nearby aquifers to dilute, disperse and sequester the bicarbonate. 
         [0035]    In yet another configuration, a carbonate mine is sited near a hydrocarbon-powered industrial operation. Captured carbon dioxide is converted to calcium bicarbonate using an AWC process. In this configuration the AWC reactor is created in-situ by rubblizing in place long chambers in the carbonate formation by use of explosives or a tunnel boring machine. The rubblized chamber is where water and flue gas are introduced, the carbon capture reaction takes place, and from which the resulting bicarbonate solution is generated, collected and then injected into saline aquifers directly below the chambers. In this configuration, large amounts of water required for diluting bicarbonate solutions formed in AWC reactors may not be necessary as the underground reactor can use modest sources of local water or nearby saline aquifers to dilute, disperse and sequester the bicarbonate. 
         [0036]    In a further embodiment, a method is disclosed for disposing of carbon dioxide captured by conventional methods by transporting the carbon dioxide from a remote location to an underground AWC facility sited near an ocean, where it can be converted to bicarbonate, diluted, and sequestered directly in the ocean. 
         [0037]    The above-described embodiments and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the invention are possible utilizing, alone or in combination, one or more of the features set forth above or described in detail below. 
         [0038]    The following definitions are used herein: 
         [0039]    The terms “at least one”, “one or more”, and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together. 
         [0040]    AWL means accelerated weathering of limestone. In this process gases containing carbon dioxide are dissolved in a solution of water and crushed limestone and limestone fines. A portion of the dissolved carbon dioxide is converted to calcium bicarbonate. 
         [0041]    AWC means accelerated weathering of carbonate mineral-containing materials. In this process gases containing carbon dioxide are dissolved in a solution of water and crushed carbonate mineral-containing materials and carbonate mineral-containing materials fines. A portion of the dissolved carbon dioxide is converted to a bicarbonate. 
         [0042]    A carbon sequestration facility is a facility in which carbon dioxide can be controlled and sequestered in a repository such as, for example, by introduction into a mature or depleted oil and gas reservoir, an unmineable coal seam, a deep saline formation, a basalt formation, a shale formation, or an excavated tunnel or cavern. 
         [0043]    Carbonate rocks are a class of sedimentary rocks composed primarily of one or more categories of carbonate minerals. The two major types of carbonate rocks are limestone and dolomite, composed primarily of calcite (CaCO 3 ) and the mineral dolomite (CaMg(CO 3 ) 2 ), respectively. Chalk and tufa are also minor sedimentary carbonates. Examples of carbonate minerals include without limitation calcite, dolomite, siderite, magnesite, ankerite, aragonite, azurite and malachite. 
         [0044]    It is to be understood that a reference to “limestone” herein is intended to include limestone, dolomite, peridotite, chalk, tufa, and other naturally occurring rocks that are known to absorb carbon dioxide. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0045]      FIG. 1  is a schematic of a AWL reactor which is prior art. 
           [0046]      FIG. 2  is a schematic of a two-stage AWL reactor. 
           [0047]      FIG. 3  is a schematic of a prior art industrial operation wherein CO2 is removed by conventional means. 
           [0048]      FIG. 4  is a schematic of an industrial operation wherein CO2 is removed by an AWL process. 
           [0049]      FIG. 5  is a schematic of an industrial operation wherein CO2 is removed by an AWL process in an excavated cavern. 
           [0050]      FIG. 6  is a schematic of a prior art barge-based AWL reactor operation. 
           [0051]      FIG. 7  is a schematic of a prior art AWL reactor operation using a surface reservoir. 
           [0052]      FIG. 8  is a schematic of a two-stage AWL reactor operation using an underground reservoir. 
           [0053]      FIG. 9  is a schematic of an AWL reactor operation using an in-situ reactor. 
           [0054]      FIG. 10  is a plan view of a two-stage AWL reactor operation using tidal action. 
           [0055]      FIG. 11  is a side view of an AWL reactor facility at high tide. 
           [0056]      FIG. 12  is a side view of an AWL reactor facility at low tide. 
           [0057]      FIG. 13  is a schematic of a prior art system for disposing of previously captured carbon dioxide. 
           [0058]      FIG. 14  is a schematic of an AWL system for disposing of previously captured carbon dioxide. 
       
    
    
     DETAILED DESCRIPTION 
       [0059]    Accelerated Weathering of Limestone or AWL is a process for reducing or eliminating carbon dioxide emissions is based on the reaction: 
         [0000]      CO 2 +H 2 O+CaCO 3  Ca+2(HCO 3 ) 
         [0000]    where the calcium and bicarbonate ions form calcium bicarbonate in solution with water. 
         [0060]    This reaction can be carried out in a water-filled reactor in which crushed limestone and limestone fines are filtered down through the water. Flue gases are injected at any one or all of multiple locations around the reactor. In addition to carbonic acid, the presence of sulphur in the solution (as weak sulphuric acid) enhances the carbon dioxide capture reaction rate. The sulphur may be captured by also introducing lime to the reactor. 
         [0061]    As can be appreciated, limestone, CaCO 3 , contains the potential for releasing fossil carbon dioxide (for example in the production of lime for cement). In the AWL reaction, this potential carbon dioxide is never released but is combined with previously released carbon dioxide to form calcium bicarbonate which incorporates the potential carbon dioxide molecule from limestone with a new carbon dioxide molecule contained in a flue gas or as previously captured carbon dioxide. 
       AWL Reactors 
       [0062]      FIG. 1  is a schematic of a prior art AWL reactor. Such a reactor is described in “Accelerated Weathering of Limestone for CO 2  Mitigation: Opportunities for the Stone and Cement Industries”, Langer, San Juan, Rau, and Caldeira, Mining Engineering, February 2009. 
         [0063]    In  FIG. 1 , crushed limestone and limestone fines are added to the reactor  101  via conduit  105  (limestone conduits denoted by dash-dot lines). Untreated ocean, lake or river water is added to the reactor  101  via conduit  106  (water conduits denoted by solid lines) until the carbonate bed  102  reaches a predetermined mixture of water and limestone. Incoming flue gases are injected into the AWL reactor  101  via conduits  103  (gas conduits denoted by dashed lines) at multiple points such as into the gas volume  110  of the reactor, into the middle of the reactor carbonate bed  102  or into the bottom of the reactor carbonate bed  102 . Gas volume  110  is comprised of a mixture of air and flue gases. After a selected residence time, a first portion of water containing a calcium bicarbonate solution is removed from the carbonate bed  102  and pumped with pump  107  through conduit  108  to the top of reactor  101  where it is recycled by spraying  109  into the gas volume  110 . A second portion of water containing a calcium bicarbonate solution is removed from the carbonate bed  102  and sent via conduit  112  for further dilution and sequestering in a nearby ocean, lake or river. The flue gases with a substantial portion of the carbon dioxide removed via conversion to calcium bicarbonate are discharged via conduit  111  into the atmosphere. As can be appreciated, valves such as  104  are used to control the flow of input and output gases as well as input and output water. 
         [0064]    The fraction of carbon dioxide removed is dependent on the ratio of reactor water flow rate to gas flow rate. Both flow rates are expressed in the same volume per time units. As this ratio increases, more carbon dioxide is converted to calcium bi-carbonate. For example, for a ratio of about 1, about 60% of the carbon dioxide introduced into the reactor is converted to calcium bicarbonate. For a ratio of about 8, about 95% of the carbon dioxide introduced into the reactor is converted to calcium bicarbonate. 
         [0065]      FIG. 2  is a schematic of a two-stage AWL reactor in which a first reactor  201  is used to dissolve flue gases in water and a second reactor  211  is used to carry out the reaction whereby calcium and bicarbonate ions form calcium bicarbonate in solution with water. Untreated ocean, lake or river water is added to reactor  201  via conduit  203 . Flue gases are introduced into water reactor  201  via conduit  204  where they dissolve in the water mass  202  to form a carbonic acid solution. A vent to the atmosphere  205  is provided to relieve the pressure in the event of a pressure buildup. A first portion of water containing dissolved flue gases is removed from the water mass  202  and pumped through conduit  206  to the top of reactor  201  where it is sprayed  209  into the gas volume above water mass  202 . A second portion of water containing dissolved flue gases is removed from reactor  201  and sent via conduit  207  to the second reactor  211 . Crushed limestone and limestone fines are added to the reactor  211  via conduit  213  as needed. A first portion of water containing a calcium bicarbonate solution is removed from the carbonate bed  212  and pumped via conduit  214  to the top of reactor  211  where it is sprayed  219  into the gas volume. A second portion of water containing a calcium bicarbonate solution is removed from the carbonate bed  212  and sent via conduit  216  for further dilution and sequestering in a nearby ocean, lake or river. The flue gases with a substantial portion of the carbon dioxide removed via the solution are discharged via conduit  215  into the atmosphere. As can be appreciated, valves are used to control the flow of input and output gases as well as input and output water. 
       Flow Charts of Processes 
       [0066]      FIG. 3  is a schematic of a prior art industrial operation  301  wherein carbon dioxide CO 2  is removed by conventional means based on the use of delivered limestone. In this configuration, a limestone mine  302  is installed in a limestone or dolomite formation near an industrial operation  301  which generates significant amounts of carbon dioxide. By siting a limestone mine  302  near the industrial operation  301 , the cost of limestone is minimized by avoiding significant transportation costs. Examples of such industrial operations include electrical power plants using hydrocarbon fuels, thermal bitumen or heavy oil recovery operations, cement plants and the like. A portion of the mined limestone may be used or sold for commercial aggregate  304 . The remainder of the mined limestone may be used for water purification  305 , sulphur capture and removal  306  and carbon dioxide capture and removal  307 . Water softening  305  is typically carried out before use in the industrial operation  301 . Reduction of hardness involves the addition of slaked lime Ca(OH) 2  to a hard water supply to remove the carbonate hardness by precipitation and filtration through the basic reaction: 
         [0000]      Ca(OH) 2 +Ca(HC0 3 ) 2  2 CaCO 3 +2 H 2 0 
         [0067]    The mined limestone is processed  321  into lime CAO and slaked lime Ca(OH) 2  by well-known processes that liberate carbon dioxide CO 2 . This “clean” carbon dioxide is considered fossil carbon dioxide and is captured  322  for future disposal. The lime is used in sulphur removal  306  and carbon dioxide removal  307  is carried out by any well-known processes such as pre-combustion, post-combustion, oxyfuel combustion or other industrial process such as ammonia production. Removal of sulphur can be carried out using lime to produce calcium sulphite CaSO 3  which, in turn, can be processed into gypsum which can be sold as a product or disposed  308 . Disposal can be by returning the calcium sulphite slurry or gypsum for example to a mined out section  303  of the limestone mine  302 . Carbon dioxide may be removed and captured  307  by using solid sorbents based on hydroxides of alkali metals such as for example calcium hydroxide Ca(OH) 2  activated with sodium hydroxide NaOH or potassium hydroxide KOH as represented by the summary reaction: 
         [0000]      Ca(OH) 2 +CO 2  CaCO 3 +H 2 O 
         [0068]    As can be seen, the production of lime liberates “clean” carbon dioxide which can be captured. The use of slaked lime to capture carbon dioxide produced in the industrial operation  301  removes carbon dioxide from, for example, the burning of fossil fuels. Both the captured carbon dioxide  322  and the calcium carbonate and residual “dirty” carbon dioxide from step  307  must be disposed. The pure carbon dioxide captured from step  322  can be used or sold for Enhanced Oil Recovery (“EOR”) usage  309  or it can be transported by rail, truck or pipeline  310  and sequestered in the ocean  311  or at a commercial carbon dioxide sequestration site  312 . Alternately, the clean carbon dioxide generated in the capture step  322  can be sequestered in a nearby aquifer  313  if conditions in the aquifer are acceptable. The calcium carbonate and residual “dirty” carbon dioxide from step  307  can be returned and disposed of in a mined out section  303  of the limestone mine  302 . 
         [0069]      FIG. 4  is a schematic of an industrial operation wherein carbon dioxide CO2 is removed by an accelerated weathering of limestone (“AWL”) process based on the use of limestone. In this configuration, a limestone mine  402  is installed in a limestone or dolomite formation near an industrial operation  401  which generates significant amounts of carbon dioxide. By siting a limestone mine  402  near the industrial operation  401 , the cost of limestone is minimized by avoiding significant transportation costs. Examples of such industrial operations include electrical power plants using hydrocarbon fuels, thermal bitumen or heavy oil recovery operations, cement plants and the like. A portion of the mined limestone may be used or sold for commercial aggregate  404 . The remainder of the mined limestone may be used for water purification  405 , sulphur capture and removal and carbon dioxide capture and removal  407  using the AWL process on the flue gases generated by the industrial operation  401 . 
         [0070]    Accelerated Weathering of Limestone or AWL is a process for reducing or eliminating carbon dioxide emissions is based on the reaction: 
         [0000]      CO 2 +H 2 O+CaCO 3  Ca+2(HCO 3 ) 
         [0000]    where the calcium and bicarbonate ions form calcium bicarbonate in solution with water. 
         [0071]    This reaction is carried out in a water filled reactor in which crushed limestone is filtered down through the water and flue gases are injected at multiple locations around the reactor. In addition to carbonic acid, the presence of sulphur in the solution (as weak sulphuric acid) enhances the carbon dioxide capture reaction rate. The sulphur may be captured by also introducing lime to the reactor. An AWL reactor is discussed in more detail in  FIG. 1 . The AWL process could be carried out in a large water reservoir in an open excavation, a portion of which may be used for the actual AWL reactor. Such a reservoir would be sited near the industrial operation  401 . The AWL reactor can also be sited underground as described in  FIGS. 8 and 9 . 
         [0072]    The sulphur from the AWL reactor  407  can be captured, disposed of or sold. If desired, a portion of the calcium bicarbonate can be turned into calcium and carbon dioxide by allowing a portion of the calcium bicarbonate solution to evaporate and capturing the CO 2  to be used for sale or EOR operations  409 . 
         [0073]    If economical, the calcium bicarbonate solution can be diluted with water and sent by rail, truck or pipeline  410  for disposal in the ocean  411 . Alternately, the calcium bicarbonate solution can be diluted with water and sequestered in a river or lake  415  or in a nearby aquifer  413 . The amount of water required to dilute the calcium bicarbonate solution from reactor  407  varies depending on the final destination. For example, a calcium bicarbonate solution may require as much as about 10,000 tons of water per ton of carbon dioxide to dispose of the resulting solution in a large river or large lake. Less dilution may be required for disposal in an aquifer. Even less dilution would be required for rail, truck or pipeline transportation. The calcium bicarbonate solution may not be required to be substantially diluted for disposal in some aquifers  413  or for disposal in a mined out section  403  of the limestone mine  402 . 
         [0074]      FIG. 5  is a schematic of an industrial operation wherein CO2 is removed by an AWL process in an excavated cavern. In this configuration, a limestone mine  502  is installed in a limestone or dolomite formation near an industrial operation  501  which generates significant amounts of carbon dioxide. By siting a limestone mine  502  near the industrial operation  501 , the cost of limestone is minimized by avoiding significant transportation costs. Examples of such industrial operations include electrical power plants using hydrocarbon fuels, thermal bitumen or heavy oil recovery operations, cement plants and the like. A portion of the mined limestone may be used or sold for commercial aggregate  504 . The remainder of the mined limestone may be used for water purification  505 . The flue gases from the industrial operation  501  are then directed to an underground cavern which serves as a large AWL reactor  516  for sulphur capture and carbon dioxide capture. The cavern  516  may be divided into chambers and a portion of the resulting calcium bicarbonate solution may be transported to a mined out section  503  of the limestone mine  502 . The advantage of this configuration is that a minimum of additional water is required to keep the calcium bicarbonate solution from evaporating and releasing gaseous carbon dioxide in the underground cavern. 
       AWL Carbon Capture Configurations 
       [0075]      FIG. 6  is a schematic of a prior art barge-based AWL reactor operation. Such an approach was suggested in “Reducing Energy-Related CO2 Emissions Using Accelerated Weathering of Limestone”, G. H. Rau, K. G. Knauss, W. H. Langer, K. Caldeira, Energy 32, 2007. This figure shows an industrial plant  601  sited near a shoreline of a large body of water  610  such as for example an ocean, a large lake or a large river. For example, the industrial plant  601  may be a hydrocarbon fuel powered electrical power plant, a cement production plant or the like. The plant  601  is shown with a tall flue gas stack  602  which is normally used to dispose of flue gases into the atmosphere. Rather than disposing of flue gases into the atmosphere, the AWL process can be used to remove a substantial portion or all of the carbon dioxide from the flue gases. It is also possible to remove sulphur and NOxs from the flue gases in an AWL reactor. In  FIG. 6 , the AWL reactor is shown formed by a barge system. This system could, for example, be comprised of barges carrying limestone and some barges carrying AWL reactors. Such a barge system  613  could be moored off the shoreline near to industrial plant  601  using a mooring station  603 . The flue gas paths are shown as continuous lines  605  and the water paths by dashed lines  607  and  608 . The flue gases from plant  601  can be transported to the barge reactor system  613  via, for example, a pipeline  605  installed underground and through the body of water  610  to the mooring station  603  where it can be connected to another pipeline  606  which directs the flue gases into the barge-based reactors  613 . Water from water body  610  is pumped in to the AWL reactors via inlet  607 , mixed with crushed limestone stored in another nearby barge. A first product of the AWL reactors is a calcium bicarbonate solution which is then disposed of via outlet  608  into the body of water  610  as a diluted calcium bicarbonate aqueous solution. A second product of the AWL reactors are flue gases minus most of the carbon dioxide, sulphur and NOxs which can be vented from the AWL reactors into the surrounding atmosphere. 
         [0076]      FIG. 7  is a schematic of a prior art AWL reactor operation using a surface reservoir. This figure shows an industrial plant  701  sited near a shoreline of a large body of water  710  such as for example an ocean, a large lake or a large river. For example, the industrial plant  701  may be a hydrocarbon fuel powered electrical power plant, a cement production plant or the like. The plant  701  is shown with a tall flue gas stack  702  which is normally used to dispose of flue gases into the atmosphere. Rather than disposing of flue gases into the atmosphere, the AWL process can be used to remove a substantial portion or all of the carbon dioxide from the flue gases. It is also possible to remove sulphur and NOxs from the flue gases in an AWL reactor. The flue gas paths are shown as continuous lines and the water paths by dashed lines. In  FIG. 7 , the AWL reactor is formed using a surface reservoir  711  such as described by item  507  in  FIG. 5  into which flue gases are directed via pipeline  705 . Water is often used for cooling in industrial plant operations. In this example, cooling water is taken from water body  710  via path  708  into plant  701  and used for cooling. The heated water is then piped via path  709  to AWL reservoir  711 . Crushed limestone is added into reservoir  711  and a diluted calcium bicarbonate solution is transported out of reservoir  711  via a second pipeline for disposal into a nearby body of water  710 . A first product of the AWL reactor is a calcium bicarbonate solution which is disposed of via pipeline  707  into the body of water  710  as a diluted calcium bicarbonate solution. Alternately, the calcium bicarbonate solution can be disposed of via well  706  into a saline aquifer  712 , if available, typically as a less diluted calcium bicarbonate solution. A second product of the AWL reactor is flue gases minus most of the carbon dioxide, sulphur and NOxs which can be allowed to vent from the AWL reactor into the surrounding atmosphere. 
         [0077]    As can be appreciated, two surface reservoirs can be used where a first reservoir is used to dissolve flue gases in water and a second reservoir is used to carry out the reaction whereby calcium and bicarbonate ions form calcium bicarbonate in solution with water. 
         [0078]      FIG. 8  is a schematic of a two-stage AWL reactor operation using underground reservoirs. This figure shows an industrial plant  801  sited near a shoreline of a large body of water  810  such as for example an ocean, a large lake or a large river. For example, the industrial plant  801  may be a hydrocarbon fuel powered electrical power plant, a cement production plant or the like. The plant  801  is shown with a tall flue gas stack  802  which is normally used to dispose of flue gases into the atmosphere. Rather than disposing of flue gases into the atmosphere, the AWL process can be used to remove a substantial portion or all of the carbon dioxide from the flue gases. It is also possible to remove sulphur and NOxs from the flue gases in an AWL reactor. The flue gas paths are shown as continuous lines and the water paths by dashed lines. In  FIG. 8 , the AWL reactor is formed using two underground caverns  814  and  815  such as described in  FIG. 2  into which flue gases are directed via pipeline  805 . Water is often used for cooling in industrial plant operations. In this example, cooling water is taken from water body  810  via path  831  and  832  into plant  801  and used for cooling. The heated water from plant  801  is then piped via path  833  to a first reactor  814  used to dissolve flue gases in water. This water is then directed via pipeline  816  to a second reactor  815  used to carry out the reaction whereby calcium and bicarbonate ions form calcium bicarbonate in solution with water. Water for the reactor  814  may also be taken from aquifer  812  if available, via path  834  which may be a well or series of wells. Alternately, water for reactor  814  may be taken directly from the body of water  810  via path  831 . Crushed limestone is also added into underground reactor  815  and a diluted calcium bicarbonate solution is transported out of underground reservoir  815  via a second pipeline  807  for disposal into a nearby body of water  810 . Alternately or in addition, a diluted calcium bicarbonate solution may be sequestered via a well or wells  806  for disposal into an aquifer  812 . A first product of the AWL reactor is a calcium bicarbonate solution which is disposed of via pipeline  1107  into the body of water  810  and or via disposal wells  806  into an aquifer  812  as a diluted calcium bicarbonate solution. A second product of the AWL reactor is flue gases minus most of the carbon dioxide, sulphur and NOxs which can be vented from the underground AWL reactor  815  into the surrounding atmosphere. 
         [0079]      FIG. 9  is a schematic of an AWL reactor operation using an in-situ reactor. Such an in-situ AWL reactor  915  can be formed in-situ by rubblizing long chambers in an underground limestone formation using drill &amp; blast, a tunnel boring machine, a roadheader machine or another excavation method. This figure shows an industrial plant  901  sited near a shoreline of a large body of water  910  such as for example an ocean, a large lake or a large river. For example, the industrial plant  901  may be a hydrocarbon fuel powered electrical power plant, a cement production plant or the like. The plant  901  is shown with a tall flue gas stack  902  which is normally used to dispose of flue gases into the atmosphere. Rather than disposing of flue gases into the atmosphere, an in situ AWL process can be used to remove a substantial portion or all of the carbon dioxide from the flue gases. The flue gas paths are shown as continuous lines and the water paths by dashed lines. Flue gases are injected into the rubblized limestone chambers via pipeline  905  and a diluted calcium bicarbonate solution reaction product is formed and either allowed to seep into the surrounding ground formations or is injected by a well or wells  906  into nearby saline aquifer  912 . It is also possible to remove sulphur and NOxs from the flue gases in an AWL reactor so the flue gases minus most of the carbon dioxide, sulphur and NOxs can be vented back to the surface for dispersal into the surrounding atmosphere or left underground to dissipate into the surrounding formation. Water is often used for cooling in industrial plant operations. In this example, cooling water is taken from water body  910  via path  931  and  932  into plant  901  and used for cooling. The heated water from plant  901  is then piped via path  933  to AWL reactor  915 . Water for the AWL reactor  915  may also be taken from aquifer  912  if available, via path  934  which may be a well or series of wells. Alternately, water for AWL reactor  915  may be taken directly from the body of water  910  via path  931 . In  FIG. 8 , the AWL reactor is formed using an underground cavern  915  such as described by item  616  in  FIG. 6  into which flue gases are directed via pipeline  905 . A diluted calcium bicarbonate solution is transported out of underground in-situ reactor  915  via a second pipeline  907  for disposal into a nearby body of water  910 . Alternately or in addition, a diluted calcium bicarbonate solution may be sequestered via a well or wells  906  for disposal into an aquifer  912 . A first product of the AWL reactor is a calcium bicarbonate solution which is disposed of via pipeline  907  into the body of water  910  and or via disposal wells  906  into an aquifer  912  as a diluted calcium bicarbonate solution. A second product of the AWL reactor is flue gases minus most of the carbon dioxide, sulphur and NOxs which can be vented from the in-situ AWL reactor  914  into the surrounding atmosphere. 
         [0080]    The advantage of the in-situ configuration of  FIG. 9  is that the limestone can be crushed by any number of excavating means and most of the crushed limestone need not be moved. That is, the material handling operations, and hence costs, can be minimized. 
       Water Management 
       [0081]    As is known, the cost of pumping millions of gallons of water vertically even for only a few meters can be a significant cost factor. Siting an AWL facility near an ocean in underground caverns can utilize the tides to fill a water chamber with sea water and then flush the calcium bicarbonate solution, formed in one or more AWL reactors, back into the ocean.  FIG. 10  is a plan view of a two-stage AWL reactor operation utilizing tidal action to move large amounts of sea water. Here an underground AWL facility is sited near an ocean  1002  where there is significant tidal variation. A first large underground cavern  1003  is used to collect sea water during incoming tides by opening gate  1011 . The water in cavern  1003  is then sent to a first underground reactor  1004  as needed by opening gate  1013 . Flue gases are introduced into reactor  1004  where carbonic acid is formed. The carbonic acid is then sent to a second underground reactor  1005  as needed by opening gate  1014 . Crushed limestone and limestone fines are introduced into reactor  1005  where a calcium bicarbonate solution is formed. The calcium bicarbonate solution is then sent to underground cavern  1006  by opening gate  1015 . A second large underground cavern  1006  is also used to collect sea water during incoming tides by opening gate  1012 . The water in cavern  1006  is used to dilute the calcium bicarbonate solution in preparation for discharging into the ocean. The discharge takes place during outgoing tides by opening gate  1012 . 
         [0082]    It is also possible to use a single cavern to bring in sea water, use the sea water in an underground AWL reactor system and then return the calcium bicarbonate solution to the cavern where the calcium bicarbonate solution can be diluted and flushed into the sea with the outgoing tide. 
         [0083]      FIG. 11  is a side view of an AWL reactor facility at high tide. This figure shows a large cavern  1103  excavated near the shore  1101  which is designed to substantially fill with sea water  1104  at high tide in ocean  1102 . Sea water enters cavern  1104  via one of more conduits  1105 . The cavern is sufficiently large enough to provide water for an AWL reactor system until the next high tide. Water flow control gates are not shown. 
         [0084]      FIG. 12  is a side view of an AWL reactor facility at low tide. This figure shows a large cavern  1203  which is designed to substantially empty of sea water  1204  at low tide in ocean  1202 . Sea water exits cavern  1204  via one of more conduits  1205 . Water flow control gates are not shown. As discussed in  FIG. 11 , the cavern can be either of caverns  1103  or  1106  in  FIG. 10 . 
       Disposal of Previously Captured Carbon Dioxide by AWL 
       [0085]    Carbon dioxide may be captured by conventional means which include pre-combustion systems such as catalytic reforming and water shifting that produces carbon dioxide that can be captured by a number of well-known methods; post-combustion systems where carbon dioxide is separated from flue gases by a number of well-known methods; oxyfuel combustion where carbon dioxide is separated from flue gases enriched in carbon dioxide by a number of well-known methods; and other industrial processes such as ammonia production that produces carbon dioxide that can be captured by a number of well-known methods. 
         [0086]      FIG. 13  is a schematic of a prior art system for disposing of previously captured carbon dioxide. This figure depicts an industrial operation  1301  that captures carbon dioxide by conventional means prior to emitting flue gases. This captured carbon dioxide may be sequestered at a nearby sequestration facility  1302  in any number of appropriate deep geological reservoirs or structures  1303 . Geological reservoirs include depleted gas and oil fields, saline formations and the like) and geological structures include abandoned mines. It is typically not sequestered in nearby rivers or lakes  1304  as carbon dioxide will cause acidification of the water. If a nearby sequestration facility  1302  is not available or too expensive, the captured carbon dioxide can be transported by train, truck or pipeline for sequestration in an ocean  1307 . For example, the carbon dioxide may be shipped by rail  1305  and off-loaded at a transfer station  1306  for transport to an off shore platform by pipeline  1308 , or by ship or barge. The carbon dioxide can then be sequestered in a deep geological reservoir  1310  under the ocean floor or sequestered in the deep ocean. Sequestering carbon dioxide in deep geological reservoirs  1303  may be expensive because of the cost of deep drilling and because of the uncertainties of the containment ability of the reservoir. Thus it may be preferable to transport the carbon dioxide for sequestration under an ocean because the greater cost is justified by removing many of the uncertainties of the containment ability of the reservoir. 
         [0087]      FIG. 14  is a schematic of an AWL system for disposing of previously captured carbon dioxide which reduces both cost and uncertainty of disposing of previously captured carbon dioxide. This figure depicts an industrial operation  1401  that captures carbon dioxide by conventional means prior to emitting flue gases. This captured carbon dioxide may be sequestered in an appropriate deep aquifer  1403  or in an appropriate nearby river or lake  1404  from a carbon dioxide sequestration facility  1402 . If a nearby sequestration site is not available, the captured carbon dioxide can be transported by train, truck or pipeline for sequestration in an ocean  1409 . For example, the carbon dioxide may be shipped by rail  1405  and off-loaded at an AWL facility  1406  where additional sea water can be added to dilute the concentrated calcium bicarbonate solution which can then be disposed by pipeline  1408  directly into the ocean  1407 . As noted previously, the net effect of this addition of calcium bicarbonate is to slightly raise the alkalinity of the sea water. This is beneficial when the sea water is slightly acidic as is the case when large amounts of carbon dioxide are sequestered in the oceans either by natural causes or dumping of carbon dioxide. 
         [0088]    A number of variations and modifications of the inventions can be used. As will be appreciated, it would be possible to provide for some features of the inventions without providing others. For example, though the embodiments are discussed with reference to use of crushed limestone, it is to be understood that the various embodiments may be used with other types of naturally occurring rocks such as dolomite, peridotite and the like. Dolomite is thought to be somewhat more active than limestone in the uptake of carbon dioxide. Peridotite is known to be very active in absorbing carbon dioxide although it is not as commonly found as limestone or dolomite. As can be appreciated, combinations of limestone, dolomite and peridotite may give rise to a faster carbon dioxide uptake reaction or a more complete carbon dioxide uptake reaction. 
         [0089]    The present invention, in various embodiments, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various embodiments, sub-combinations, and subsets thereof. Those of skill in the art will understand how to make and use the present invention after understanding the present disclosure. The present invention, in various embodiments, includes providing devices and processes in the absence of items not depicted and/or described herein or in various embodiments hereof, including in the absence of such items as may have been used in previous devices or processes, for example for improving performance, achieving ease and\or reducing cost of implementation. 
         [0090]    The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the invention are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the invention. 
         [0091]    Moreover though the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.