Apparatus and Method for Carbon Dioxide Recovery

Abstract

An apparatus and process for use of an alkaline reagent (e.g. sodium hydroxide, NaOH, potassium hydroxide, KOH, etc.) to facilitate removal of carbon dioxide (CO2) from flue gas output from a glass melting operation. The CO2 removed from the flue gas can be in carbonates formed in the reaction of the reagent with the flue gas, which can be used in glass melting operations. A portion of the flue gas can also be liquefied in some embodiments to produce a liquefied CO2 stream for other uses. In some embodiments, a portion of the carbonate generated from the CO2 removal process can be heated (e.g. in an indirect heat exchange process) to liberate the CO2 for feeding the liberated CO2 to a liquefaction process while a resultant oxide formed via the CO2 liberation can be hydrolyzed to regenerate the alkaline reagent for subsequent use in the CO2 removal process.

Claims

1. A method of recovering carbon dioxide (CO.sub.2) from a flue gas output from a furnace being operated to melt glass, comprising: feeding the flue gas to a CO.sub.2 capture unit after the flue gas is treated via at least one process gas treatment element (PGTE) positioned between the furnace and the CO.sub.2 capture unit; treating a first portion of the flue gas with at least one alkaline reagent within the CO.sub.2 capture unit so that CO.sub.2 of the first portion of the flue gas reacts with the alkaline reagent to form at least one carbonate material; feeding at least a portion of the carbonate material from the CO.sub.2 capture unit to the furnace for mixing with other feed material for forming molten glass in the furnace.

2. The method of claim 1, wherein the at least one alkaline reagent includes XOH, wherein the X is Na or K.

3. The method of claim 1, wherein the at least one alkaline reagent includes: calcium hydroxide (Ca(OH).sub.2), sodium hydroxide (NaOH) or potassium hydroxide (KOH).

4. The method of claim 3, wherein the carbonate material includes limestone (CaCO.sub.3), soda ash (Na.sub.2CO.sub.3) or potassium carbonate (K.sub.2CO.sub.3).

5. The method of claim 4, wherein the at least one PGTE includes a candle filter or a high-temperature filter device.

6. The method of claim 4, wherein the at least one PGTE includes a SO.sub.2 removal unit and an electrostatic precipitator that is positioned between the SO.sub.2 removal unit and the CO.sub.2 capture unit.

7. The method of claim 1, comprising: passing the flue gas through at least one heat exchanger to heat at least one of a flow of fuel and an oxidant flow before the first portion of the flue gas is fed to the CO.sub.2 capture unit and after the first portion of the flue gas is output from the at least one PGTE.

8. The method of claim 1, comprising: feeding a first portion of the carbonate material output from the CO.sub.2 capture unit to the furnace and regenerating a second portion of the carbonate material output from the CO.sub.2 capture unit to form the at least one alkaline reagent from the second portion of the carbonate material.

9. The method of claim 1, comprising: feeding a second portion of the flue gas output from the at least one PGTE to a CO.sub.2 liquefaction system to liquefy CO.sub.2 within the second portion of the flue gas.

10. The method of claim 1, wherein the at least one PGTE is fed at least one alkaline reagent to treat the flue gas upstream of the CO.sub.2 capture unit.

11. An apparatus for capturing carbon dioxide (CO.sub.2) from a flue gas output from a melting furnace, the apparatus comprising: a CO.sub.2 capture unit positionable downstream of the furnace to receive a first portion of flue gas output from the furnace, the CO.sub.2 capture unit configured so that the first portion of the flue gas reacts with at least one alkaline reagent within the CO.sub.2 capture unit so that CO.sub.2 of the first portion of the flue gas reacts with the at least one alkaline reagent to form at least one carbonate material; the CO.sub.2 capture unit positionable such that at least a portion of the carbonate material is outputtable from the CO.sub.2 capture unit to feed the carbonate material to the furnace.

12. The apparatus of claim 11, wherein the at least one alkaline reagent includes calcium hydroxide (Ca(OH).sub.2), sodium hydroxide (NaOH) and potassium hydroxide (KOH).

13. The apparatus of claim 12, wherein the carbonate material includes limestone (CaCO.sub.3), soda ash (Na.sub.2CO.sub.3) and/or potassium carbonate (K.sub.2CO.sub.3).

14. The apparatus of claim 11, wherein the CO.sub.2 capture unit includes at least one reactor.

15. The apparatus of claim 11, comprising: at least one process gas treatment element (PGTE) positionable between the CO.sub.2 capture unit and the furnace to receive the flue gas output from the furnace to treat the flue gas before the first portion of the flue gas is fed to the CO.sub.2 capture unit.

16. The apparatus of claim 15, comprising: at least one heat exchanger positionable between the at least one PGTE and the CO.sub.2 capture unit so that flue gas output from the at least one PGTE is passed through the at least one heat exchanger to reduce a temperature of the flue gas before the first portion of the flue gas is fed to the CO.sub.2 capture unit.

17. The apparatus of claim 16, comprising: at least one acid gas removal unit positionable to receive the flue gas upstream of the CO.sub.2 capture unit.

18. The apparatus of claim 15, comprising: a CO.sub.2 liquefaction system positionable to receive a second portion of the flue gas that is split from the first portion of the flue gas after the flue gas is output from the at least one PGTE.

19. The apparatus of claim 11, wherein a first portion of the carbonate material is feedable to the furnace and the apparatus comprising: an alkaline reagent regeneration system downstream of the CO.sub.2 capture unit to receive a second portion of the carbonate material to form the at least one alkaline reagent from the second portion of the carbonate material.

20. The apparatus of claim 19, wherein the alkaline reagent regeneration system comprises: a CO.sub.2 liberation device that liberates CO.sub.2 from the carbonate material to form oxides; and a hdyrolization unit to hydrolyze the oxides outputtable from the CO.sub.2 liberation device to form the at least one alkaline reagent such that the formed at least one alkaline reagent is feedable to the CO.sub.2 capture unit.

21. A method of recovering carbon dioxide (CO.sub.2) from a flue gas output from a furnace or reactor, comprising: feeding the flue gas to a CO.sub.2 capture unit after the flue gas is treated via at least one process gas treatment element (PGTE) positioned between the furnace or reactor and the CO.sub.2 capture unit; treating a first portion of the flue gas with at least one alkaline reagent within the CO.sub.2 capture unit so that CO.sub.2 of the first portion of the flue gas reacts with the alkaline reagent to form at least one carbonate material; feeding a first portion of the carbonate material from the CO.sub.2 capture unit to an alkaline reagent regeneration system; reacting the first portion of the carbonate material with hydrated lime (Ca(OH).sub.2) in a reagent regeneration reactor of the alkaline reagent regeneration system to precipitate calcium carbonate (CaCO.sub.3) and liberate the alkaline reagent for feeding to the CO.sub.2 capture unit; heating the CaCO.sub.3 in a CO.sub.2 liberation unit or a lime kiln to liberate CO.sub.2 from the CaCO.sub.3 and generate calcium oxide (CaO); and hydrolyzing the CaO to form Ca(OH).sub.2 to feed the formed Ca(OH).sub.2 to the reagent regeneration reactor of the alkaline reagent regeneration system.

22. An apparatus for capturing carbon dioxide (CO.sub.2) from a flue gas output from a furnace or reactor, the apparatus comprising: a CO.sub.2 capture unit positionable downstream of the furnace or reactor to receive a first portion of flue gas output from the furnace, the CO.sub.2 capture unit configured so that the first portion of the flue gas reacts with at least one alkaline reagent within the CO.sub.2 capture unit so that CO.sub.2 of the first portion of the flue gas reacts with the at least one alkaline reagent to form at least one carbonate material; an alkaline reagent regeneration system downstream of the CO.sub.2 capture unit, the alkaline reagent regeneration system comprising: a regeneration reactor positioned to receive the carbonate material to react the carbonate material with hydrated lime (Ca(OH).sub.2) to precipitate calcium carbonate (CaCO.sub.3) and liberate the alkaline reagent for feeding to the CO.sub.2 capture unit; a CO.sub.2 liberation unit positioned to receive the CaCO.sub.3 from the regeneration reactor of the alkaline reagent regeneration system to liberate CO.sub.2 from the CaCO.sub.3 and generate calcium oxide (CaO); a hydrolysis unit positioned to receive the CaO to hydrolyze the CaO to form Ca(OH).sub.2 so the formed Ca(OH).sub.2 is feedable to the regeneration reactor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Exemplary embodiments of apparatuses and processes for the recovery of CO2 from a flue gas emitted from glass melting operations, glass melting systems that can incorporate such apparatuses and/or processes, glass manufacturing plants, glass melting apparatuses, glass manufacturing furnace arrangements, and methods of making and using the same are shown in the drawings included herewith. It should be understood that like reference characters used in the drawings may identify like components.

[0052] FIG. 1 is a block diagram of a first exemplary embodiment of a glass melting apparatus 1 that can utilize a first exemplary embodiment of an apparatus for the recovery of CO2 from a flue gas emitted from glass melting operations. A first exemplary embodiment of a process for the recovery of CO2 from a flue gas emitted from glass melting operations can also be appreciated from FIG. 1.

[0053] FIG. 2 is a block diagram of a second exemplary embodiment of a glass melting apparatus 1 that can utilize a second exemplary embodiment of an apparatus for the recovery of CO2 from a flue gas emitted from glass melting operations. A second exemplary embodiment of a process for the recovery of CO2 from a flue gas emitted from glass melting operations can also be appreciated from FIG. 2.

[0054] FIG. 3 is a block diagram of a third exemplary embodiment of a glass melting apparatus 1 that can utilize a third exemplary embodiment of an apparatus for the recovery of CO2 from a flue gas emitted from glass melting operations. A third exemplary embodiment of a process for the recovery of CO2 from a flue gas emitted from glass melting operations can also be appreciated from FIG. 3.

[0055] FIG. 4 is a block diagram illustrating an alkaline reagent regeneration system 13 that can be utilized in an exemplary process for alkaline reagent regeneration (also referred to as XOH Regen.). This exemplary embodiment of the alkaline reagent regeneration system 13 that can be utilized in the embodiments of FIGS. 1, 2, and 3 is also shown in broken line in FIGS. 1, 2, and 3.

[0056] FIG. 5 is a block diagram illustrating another embodiment of an alkaline reagent regeneration system 13 that can be utilized in an exemplary process for alkaline reagent regeneration (also referred to as XOH Regen.). This exemplary embodiment of the alkaline reagent regeneration system 13 that can be utilized in the embodiments of FIG. 1, 2, 3 or 4.

[0057] Exemplary process parameters (e.g. temperature, CO2 concentration, etc.) are identified in FIGS. 1-3. It should be appreciated that these are exemplary process parameters that provide non-limiting examples of how embodiments of the process and apparatus can be utilized.

DETAILED DESCRIPTION

[0058] Referring to FIGS. 1-4, a glass melting apparatus 1 can include a furnace 3 that is for melting feed material to form molten glass. The feed material can include lime, cullet and batch raw glass feed material (e.g. silica, etc.). The feed material can also include liquid or solid hydrocarbons and carbonate material. The carbonate material fed to the furnace 3 can include limestone (CaCO3), dolomite (CaMg(CO3)2), soda ash (Na2CO3) and/or potassium carbonate (K2CO3).

[0059] Fuel (e.g. natural gas, etc.) and an oxidant (e.g. air, oxygen enriched air, a flow of gases that includes oxygen, etc.) can be fed to the furnace 3 to combust the fuel for heating the feed of glass raw materials within a cavity or chamber of the furnace 3 to form the molten glass.

[0060] Flue gas formed from the combustion of fuel for generating the heat in the furnace 3 to melt the feed material to form molten glass can be output from the furnace via at least one flue gas output. The temperature of the flue gas that is output from the furnace 3 can be very hot (e.g. a temperature within a pre-selected furnace flue gas output temperature range such as, for example, up to 1,400 C., between 1,000 C. and 1,400 C., between 1,000 C. and 1,500 C., or other furnace outlet temperature).

[0061] As can be appreciated from the embodiments of FIGS. 1-3, an apparatus for capturing CO2 from flue gas output from a glass melting furnace can include a CO2 capture unit 15 that is positionable downstream of the furnace 3 to receive a first portion of flue gas output from the furnace. The CO2 capture unit 15 can be configured so that the first portion of the flue gas reacts with at least one alkaline reagent within the CO2 capture unit so that CO2 of the first portion of the flue gas reacts with the at least one alkaline reagent to form at least one carbonate material. The CO2 capture unit 15 can be positionable such that at least a portion of the carbonate material is outputtable from the CO2 capture unit to feed the carbonate material to the furnace 3.

[0062] At least one process gas treatment element (PGTE) can be positionable between the CO2 capture unit 15 and the furnace 3 to receive the flue gas output from the furnace to treat the flue gas before the first portion of the flue gas is fed to the CO2 capture unit 15. At least one heat exchanger can also be positionable between the at least one PGTE 6 and the CO2 capture unit 15 so that flue gas output from the at least one PGTE 6 is passable through the at least one heat exchanger 9 to reduce a temperature of the flue gas before the first portion of the flue gas is fed to the CO2 capture unit 15. At least one acid gas removal unit 10 can be positionable to receive the flue gas upstream of the CO2 capture unit 15 to treat the flue gas to remove acid gas components from the flue gas before the first portion of the flue gas is treated by the CO2 capture unit 15. Embodiments can also utilize a CO2 liquefaction system 11 positionable to receive a second portion of the flue gas that can be split from the first portion of the flue gas after the flue gas is output from the at least one PGTE 6, at least one heat exchanger 9, or acid gas removal unit 10.

[0063] In some embodiments, the furnace 3 can receive a first portion of the carbonate material from the CO2 capture unit 15. An alkaline reagent regeneration system 13 that can be positioned downstream of the CO2 capture unit 15 to receive a second portion of the carbonate material to form the at least one alkaline reagent from the second portion of the carbonate material. As may best be appreciated from FIGS. 3 and 4, the alkaline reagent regeneration system can include a CO2 liberation device 31 that can liberate CO2 from the carbonate material to form oxides and a hydrolization unit 33 that can be positioned and configured to hydrolyze the oxides outputtable from the CO2 liberation device 31 to form the at least one alkaline reagent. The formed at least one alkaline reagent can be output from the hydrolization unit 33 so that the formed alkaline reagent is feedable to the CO2 capture unit 15.

[0064] The flue gas temperature from flue gas output from the furnace 3 can be reduced by diluting the flue gas with air and/or water that can be fed for direct contact with the flue gas to lower the temperature of the flue gas. A water spray and/or air dilution feed can be passed to the flue gas to directly contact the flue gas to lower its temperature, for example. The lowered flue gas temperature can be within a pre-selected flue gas transport temperature range that is suitable for being conveyed via a flue gas feed conduit to at least one process gas treatment element (PGTE) 6. The conduit can be metal ducts, an array of conduits and valves, or other conduit arrangement, for example. The at least one PGTE 6 can be positioned downstream of the furnace 3 and upstream of at least one heat exchanger 9 and also be positioned upstream of a carbon dioxide capture unit 15.

[0065] As can be appreciated from FIGS. 1-3, the at least one PGTE 6 can include a high-temperature filter device 8 (e.g. a filter device that has an operating temperature over 500 C., over 600 C., over 700 C., in a range of 500 C.-900 C., in a range of 600 C.-900 C., or in a range of 700 C. to 900 C., etc.) or can include an electrostatic precipitator 7 or other type of particulate filter (e.g. a baghouse) that is positioned in series with a sulfur dioxide (SO2) removal unit 5. The SO2 removal unit 5 can include a SO2 scrubber, a dry sorbent injection SO2 scrubber, a sorbent injection scrubber, or other device that can receive trona and/or the alkaline reagent (e.g. XOH) for removal of SO2 as well as other constituents (e.g. CO2) from the flue gas passed therethrough. It should be appreciated that trona is also referred to as trisodium hydrogendicarbonate dihydrate, and sodium sesquicarbonate dihydrate, (e.g. Na2CO3.Math.NaHCO3.Math.2H2O). Trona is a type of non-marine evaporite mineral.

[0066] XOH can include at least one alkaline reagent where X can be Na or K such that XOH can refer to KOH or NaOH. XOH can also refer to Ca(OH)2.

[0067] The temperature of the flue gas that is passed to at least one PGTE 6 can be within a pre-selected flue gas treatment temperature range. This temperature can be less than 450 C. in some embodiments or be in a range of 300 C. and 500 C. (e.g. be 425 C., 400 C., etc.). In embodiments where the at least one PGTE 6 includes the high-temperature filter device 8, the temperature can be higher as noted above (e.g. can be in the range of between 700 C. and 900 C. or in the range of 600 C. and 900 C.

[0068] After the flue gas is output from at least one PGTE 6 in the embodiments of FIGS. 1-3, the flue gas can be fed to at least one heat exchanger 9 to cool the flue gas and heat one or more other process streams. For example, the flue gas can be passed through a heat exchanger to warm fuel and an oxidant flow (e.g. air, oxygen enriched air, etc.) before the oxidant and fuel are fed to the furnace for combustion of the fuel therein. After being output from the one or more heat exchangers 9, the flue gas can be fed to at least one acid gas removal devices (e.g. wash tower, scrubber, etc.). Trona and/or the alkaline reagent (e.g. XOH) can be fed to such devices to facilitate acid gas removal in some embodiments. FIGS. 2 and 3 illustrate examples of how at least one acid gas removal unit 10 can be positioned to treat the flue gas after the flue gas is output from the one or more heat exchangers 9, for example.

[0069] After being passed through one or more acid gas removal devices 10 or after being passed out of at least one heat exchanger 9, at least a portion of the flue gas can be passed through a CO2 capture unit 15. In some embodiments, the portion may be the entirety of the flue gas. In other embodiments, a first portion can be passed to the CO2 capture unit 15 and a second portion of the flue gas can be passed to a stack 19 for being emitted to atmosphere. The second portion may be passed to the stack 19 or may first be passed through a CO2 liquefaction system 11 before being passed to the stack 19. In yet other embodiments, a third portion of the flue gas can be passed from the heat exchanger 9 or at least one acid gas removal device 10 to a CO2 liquefaction system 11 (identified via broken line in FIGS. 1 and 2) for partial condensation of the flue gas in at least one condenser 11a for forming liquid CO2 and non-condensed vapors output from the condenser 11a. The non-condensed vapors can be fed back to the stack 19 via a vapor conduit 11b positioned between the stack 19 and the one or more condensers 11a.

[0070] For example, referring to the embodiments of FIGS. 1 and 3, the flue gas can be passed to an SO2 scrubber or other type of SO2 removal unit 5 and then output from the SO2 removal unit 5 to be fed to an electrostatic precipitator 7 or baghouse to remove particulates from the flue gas. Conduits can be arranged to interconnect the SO2 removal unit 5 and the electrostatic precipitator 7 so that flue gas output from the SO2 removal unit 5 can be fed to the precipitator 7. A heat exchanger feed conduit can connect the electrostatic precipitator 7 to one or more heat exchangers 9 for feeding the treated flue gas output from the electrostatic precipitator 7 to the one or more heat exchangers 9 for providing pre-heating to fuel and/or oxidant streams passed through the heat exchanger(s) 9 before the oxidant and fuel are fed to the furnace for being combusted therein for forming the molten glass. The flue gas output from the one or more heat exchangers 9 can be cooled as a result of the heating of the fuel and oxidant flows passed through the one or more heat exchangers 9.

[0071] Referring to the embodiment of FIG. 2, the flue gas can be passed from the furnace 3 to a high-temperature filter device 8 for particulate removal after the flue gas is cooled via air dilution and/or water spray. A conduit can connect the high-temperature filter device 8 to one or more heat exchangers 9 (not shown in FIG. 2) so that the flue gas output from the high-temperature filter device can be cooled while the heat from the flue gas is used to pre-heat fuel and/or an oxidant flow (e.g. O2, air, O2 enriched air, etc.) that is to be fed to the furnace for combustion of the fuel therein. It is also possible, as shown in FIG. 3 for example, that no such heat exchangers are utilized. Instead, the treated flue gas can be passed to an acid gas removal unit 10 and subsequently split into multiple streams for CO2 recovery or carbonate production.

[0072] Use of a high-temperature filter device 8 (e.g. a candle filter or other type of high-temperature filter device) as shown in FIG. 2 can provide some additional advantages. For example, the high-temperature filter device 8 can operate at a higher temperature and can be utilized for particulate removal in place of an electrostatic precipitator or baghouse. The higher temperature operation of the filter candle 8 relative to the typical operational temperature of an SO2 removal unit 5 and/or electrostatic precipitator 7 can enable a lower dilution of the flue gas that can provide at least three beneficial effects as compared to use of the SO2 removal unit 5 and/or electrostatic precipitator 7 that include: [0073] (1) lowering total mass flow of the flue gas, which can reduce the size of downstream gas processing equipment; [0074] (2) increase the CO2 concentration within the flue gas to facilitate the removal of CO2 relative to a more diluted CO2 stream; and [0075] (3) provide a higher flue gas temperature that can enable higher proportion of waste energy to be recovered via heat exchangers (e.g. one or more heat exchangers 9) for other plant processes.

[0076] The CO2 concentration within the flue gas output from the at least one PGTE 6 and/or from the acid gas removal unit 10 can be relatively low for purposes of CO2 capture. For example, there can be a CO2 concentration of 15 vol % CO2 in the flue gas, a CO2 concentration in the range of 15 vol % to 75 vol % CO2 in the flue gas, or a CO2 concentration in the range of 10 vol % to 75 vol % CO2 in the flue gas. In some applications, the CO2 in the flue gas can be a CO2 concentration in the 10 vol % to 20 vol % range, or 12 vol % to 25 vol % range or be greater than the vol % range, for example.

[0077] The flue gas output from the one or more heat exchangers 9 or acid gas removal unit 10 can be subsequently processed for CO2 capture. In the embodiments of FIGS. 1 and 2, the flue gas output from the one or more heat exchangers 9 or acid gas removal unit 10 can be split into at least a first portion and a second portion. The first portion of the flue gas can be passed to a CO.sub.2 capture unit 15 for CO.sub.2 capture and a second portion of the flue gas can be passed to at least one condenser 11a of a CO.sub.2 liquefaction system 11 for condensing of CO.sub.2 of the flue gas of the second portion of the flue gas to form a liquid CO.sub.2 stream. Non-condensed vapor output from the at least one condenser 11a can be passed to a stack 19 for emission to atmosphere via the vapor conduit 11b. A fan 20 can be connected to a non-condensed vapor conduit 11b connected between the stack 19 and the one or more condensers 11a to help facilitate the flow of the non-condensed vapor output from the at least one condenser 11a to the stack 19. The liquid CO.sub.2 that is output from the one or more condensers 11a can be fed to a pipeline for transport or can be fed to a vessel for storage and subsequent transport or for storage for sequestration.

[0078] In some embodiments of the CO2 liquefaction system 11, the condensing of the CO2 can be performed such that the CO2 is solidified and output as solid material. CO2 solidification can occur in such embodiments based on the pressure and temperature operational parameters of the one or more condensers 11a.

[0079] In some embodiments, the flue gas can also include a split third portion that is fed directly to the stack 19 for emitting to the atmosphere. In other embodiments, there may not be such a third portion. In yet other embodiments, there may only be a first portion fed to a CO2 capture unit 15 and another portion that is fed to the stack 19. The portion fed to the stack 19 can be considered a second portion for the flue gas in such embodiments.

[0080] The first portion of the flue gas fed to the CO.sub.2 capture unit 15 can pass through a CO.sub.2 capture conduit positioned between the CO.sub.2 capture unit 15 and the heat exchanger(s) 9 or acid gas removal unit 10 for being fed to the CO.sub.2 capture unit 15. An alkaline reagent can be fed to the flue gas passing through the CO.sub.2 capture conduit and/or fed to the CO.sub.2 capture unit 15 for reacting with the CO.sub.2 within the first portion of the flue gas. The alkaline regent can include XOH, for example. As discussed above, the alkaline reagent can react with the CO.sub.2 within the flue gas to remove the CO.sub.2 and form carbonates (e.g. XOH can react with the CO.sub.2 of the flue gas to form X.sub.2CO.sub.3, XHCO.sub.3, XCO.sub.3, etc.). It should be appreciated that examples of the formed carbonates include CaCO.sub.3, Na.sub.2CO.sub.3 or K.sub.2CO.sub.3. The formed carbonates can be within a slurry (e.g. a liquid) that is formed as a result of the reaction of the alkaline reagent with the CO.sub.2 within the CO.sub.2 capture unit 15. The non-condensed, or non-liquefied portion of the flue gas passed out of the CO.sub.2 capture unit 15 can be output to the stack 19 for being emitted to the atmosphere. The liquefied portion having the carbonates therein can be passed to one or more heat exchangers or otherwise undergo heating to form carbonate material suitable for being fed to the furnace 3.

[0081] It should be appreciated that the CO.sub.2 capture unit 15 can include a reactor that receives the alkaline reagent (e.g. XOH) and the first portion of the flue gas to facilitate the reaction of the reagent with the CO.sub.2 of the flue gas to form the carbonate material. This formed material can include a slurry that includes XCO.sub.3, X.sub.2CO.sub.3 and/or XHCO.sub.3, for example. A furnace carbonate feed conduit can be connected between the CO.sub.2 capture unit 15 and the furnace 3 for feeding the carbonate material output from the CO.sub.2 capture unit 15 to the furnace 3.

[0082] In some embodiments, heat can be applied to the reactor to heat the formed carbonate slurry material to facilitate formation of carbonate material that can be reintroduced to the furnace 3 as a part of the carbonate feed material that is heated for the formation of the molten glass. In other embodiments, the formed slurry material output from the reactor can subsequently be heated via at least one heat exchanger to further heat the material so non-carbonate material within the slurry (e.g. XHCO3) can be heated to form into carbonate material prior to that material being fed to the furnace. In yet other embodiments, the slurry having carbonate material can be output from the CO.sub.2 capture unit 15 for being fed to the furnace 3 for being heated therein for forming the molten glass material.

[0083] Not all of the vapor of the flue gas will be reacted with the alkaline reagent to form a carbonate containing slurry. The remaining vapor that is present after the reaction of the flue gas with the alkaline reagent can be output from the CO.sub.2 capture unit 15 for being fed to the stack 19 as noted above. A fan 20 can be connected to a non-condensed vapor conduit 17 connected between the stack 19 and the CO.sub.2 capture unit 15 to help facilitate the flow of the non-condensed vapor output from the CO.sub.2 capture unit 15 to the stack 19.

[0084] As may best be appreciated from FIG. 3, some embodiments can include a furnace 3 that has a regenerative air-fuel furnace with optional oxygen lancing, boosting, or enrichment (e.g. a left hand side regenerator, or LHS Regenerator and a right hand side regenerator, or RHS Regenerator). Each regenerator can include a regenerator chamber in which a checkerwork of refractory bricks has been stacked or otherwise positioned. Fuel and combustion oxidant flows (e.g. air, etc.) can be cycled every regenerative air-fuel cycle time period (e.g. 20 minutes, every pre-selected time period in a range of 10 minutes and 30 minutes, etc.). While one of the regenerators can preheat the oxidant flow (e.g. combustion air), the other regenerator can recover heat from the flue gas. Fuel can be fed directly to one or more burner nozzles without any preheating in such an arrangement.

[0085] As may best be appreciated from FIGS. 1-4, embodiments can also be arranged and configured so that a portion of the carbonate material that is formed via the CO.sub.2 capture unit 15 can be utilized to regenerate the alkaline reagent (e.g. XOH) for recycling back to the CO.sub.2 capture unit 15 for use therein and/or for use in other process elements (e.g. acid gas removal unit 10, SO.sub.2 removal unit 5). For example, embodiments can include an alkaline agent regeneration system 13, which is also be referred to as an XOH Regen. in FIGS. 1, 2 and 4. The alkaline agent regeneration system 13 can include a CO.sub.2 liberation unit 31 that can receive an indirect heat exchange stream, which can include a hot process stream of fluid (e.g. steam, hot gas from a plant, etc.) to heat a portion of carbonate material output from the CO.sub.2 capture unit 15. For instance, a first portion of the carbonate material output from the CO.sub.2 capture unit 15 can be fed to the furnace 3 for being fed therein for forming molten glass material and a second portion of the carbonate material output from the CO.sub.2 capture unit 15 can be fed to the CO.sub.2 liberation unit 31 for being indirectly heated via the hot indirect heat exchange stream fed therein. The heating of the carbonate material can form oxide material that can be output from the CO.sub.2 liberation unit 31 for being fed to a hydrolization unit 33 for hydrolyzing the oxides for forming the alkaline reagent (e.g. XOH) for outputting the XOH for being fed to the CO.sub.2 capture unit 15 and/or other process elements that may utilize the alkaline reagent. Another output flow output from the hydrolization unit 33 that can include a byproduct flow that is a byproduct of the hydrolization of the oxide material for regeneration of the alkaline reagent. This byproduct flow can be output for subsequent use or treatment in the apparatus as well.

[0086] CO2 liberated from the carbonate material can be output within a vapor flow output from the CO2 liberation unit 31 for being fed to a CO2 liquefaction unit 32. In some embodiments, the CO2 liquefaction unit 32 can include the CO2 liquefaction unit system 11 (e.g. one or more condensers 11a, etc.). In other embodiments, the CO2 liquefaction unit 32 can be a separate CO2 liquefaction unit that can utilize one or more CO2 condensers for condensing the vapor output from the CO2 liberation unit. Non-condensed vapor output from the CO2 liquefaction unit 32 can be passed to the stack 19. The condensed CO2 can be passed to a pipeline, a storage vessel, or be further processed for solidification and/or sequestration.

[0087] As may be appreciated from FIG. 5, the reagent regeneration system 13 can have other configurations. For instance, the reagent regeneration system 13 for either NaOH or KOH as the alkaline reagent, XOH can also be configured so that the resulting carbonate material or a portion of the carbonate material that is formed via the CO.sub.2 capture unit 15 can be fed to a regeneration reactor 34 with hydrated lime Ca(OH).sub.2 as shown in FIG. 5. The reaction of the carbonate material with the hydrated lime in the reactor 34 can precipitate calcium carbonate (CaCO.sub.3) while regenerating the alkaline reagent (XOH). The calcium carbonate can be fed into a CO.sub.2 liberation unit 31 that is configured as a lime kiln or other suitable device that can be indirectly heated to a temperature within a pre-selected calcium carbonate CO.sub.2 liberation temperature (e.g. a temperature of over 700 C.) to liberate the CO.sub.2 and generate calcium oxide CaO, which then can be fed into a hydrolyzation unit 33 and the resulting hydrated lime can be recycled back into the regeneration reactor 34. The regenerated NaOH or KOH can be put into an intermediate storage tank 35 (not shown) and subsequently fed back into CO.sub.2 capture unit 15. This type of regeneration process as shown in FIG. 5 can be applied to a CO.sub.2 capture system from any flue gas and not limited to flue gas from glass furnaces.

[0088] The CO2 liberated from the calcium carbonate via the CO2 liberation unit 31 can be output within a vapor flow output from the CO2 liberation unit 31 for being fed to a CO2 liquefaction unit 32. In some embodiments, the CO2 liquefaction unit 32 can include the CO2 liquefaction unit system 11 (e.g. one or more condensers 11a, etc.). In other embodiments, the CO2 liquefaction unit 32 can be a separate CO2 liquefaction unit that can utilize one or more CO2 condensers for condensing the vapor output from the CO2 liberation unit. Non-condensed vapor output from the CO2 liquefaction unit 32 can be passed to the stack 19. The condensed CO2 can be passed to a pipeline, a storage vessel, or be further processed for solidification and/or sequestration.

[0089] Glass melting furnace systems and apparatuses for the recovery of CO2 from a flue gas emitted from glass melting operations that can be incorporated into the systems can be configured to include process control elements positioned and configured to monitor and control operations (e.g. temperature and pressure sensors, flow sensors, an automated process control system having at least one work station that includes a processor, non-transitory memory and at least one transceiver for communications with the sensor elements, valves, and controllers for providing a user interface for an automated process control system that may be run at the work station and/or another computer device of the system, etc.).

[0090] Embodiments discussed herein can provide for an economical process for CO2 capture even for flows that have relatively low CO2 concentrations (e.g. concentration in the 10 vol % to vol % range, etc.). For example, conventional amine based processes often require substantial capital and operating costs that cannot be recovered using flows having such low CO2 concentrations. As an alternative to such conventional approaches, embodiments discussed herein can permit the captured CO2 to be economically reused for formation of carbonate material that can be used in the on-site glass making process (e.g. molten glass formation within furnace 3). This approach can avoid incurring such excessive costs and allow for reductions in raw material costs as well as other beneficial synergies while also allowing a significant reduction in greenhouse gas emissions from operation of the plant for making glass. Embodiments can also be configured so that sequestration or favorable geology required for such sequestration is not needed for economical capture of CO2 for reduction in greenhouse gas emissions. Further, embodiments can be configured so that use of a pipeline to provide for a commercially viable CO2 capture system is not required (though such a pipeline can be used in embodiments where such a use is warranted), which can permit a commercially viable reduction in greenhouse gas emissions in glass melting operations in a wider array of settings and plant locations.

[0091] It should be appreciated that different embodiments can be configured to meet a particular set of design criteria. For example, a particular set of pressure, temperature and flow rate criteria can be adjusted for different process elements of the apparatus for use in an embodiment of our process to meet a particular set of design criteria. As another example, the type and arrangement of various process elements (e.g. heat exchangers, pumps, fans, conduits, furnace 3, PGTE 6, etc.) can be adapted to meet a particular set of design criteria. As yet another example, the type of reactor that may be utilized as a CO2 capture unit 15 or type of unit to utilize for the acid gas removal unit 10 or SO2 removal unit 5 can be any of a number of suitable options that may be used to meet a particular set of design criteria.

[0092] As another example, it is contemplated that a particular feature described, either individually or as part of an embodiment, can be combined with other individually described features, or parts of other embodiments. The elements and acts of the various embodiments described herein can therefore be combined to provide further embodiments. Thus, while certain exemplary embodiments of a glass melting plants, apparatuses and processes for the recovery of CO2 from a flue gas emitted from glass melting operations, glass manufacturing furnace arrangements, and methods of making and using the same have been shown and described above, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.