Method and process for capturing carbon dioxide from marine engines

Abstract

A method and modular desulfurization-decarbonization apparatus for removing contaminants from exhaust gas is described. The apparatus comprises discrete modular units with distinct functions. The modular units may be housed in standard shipping containers and installed on cargo ships. The modules can be removed and replaced while docking with minimal disruption to ship and port operations.

Claims

1. A modular desulfurization-decarbonization apparatus for removing contaminants from exhaust gas comprising: a desulfurizing and decarbonizing reactor module; an equipment module; and a chemical storage module.

2. The modular desulfurization-decarbonization apparatus of claim 1, wherein the equipment module comprises a recirculation tank.

3. The modular desulfurization-decarbonization apparatus of claim 2, wherein the recirculation tank comprises a segregated spent sulfite tank.

4. The modular desulfurization-decarbonization apparatus of claim 2, wherein the recirculation tank comprises a segregated sulfite recirculation tank.

5. The modular desulfurization-decarbonization apparatus of claim 2, wherein the recirculation tank comprises a segregated makeup water tank.

6. The modular desulfurization-decarbonization apparatus of claim 1, wherein the equipment module comprises a control system.

7. The modular desulfurization-decarbonization apparatus of claim 1, further comprising two or more chemical storage modules.

8. The modular apparatus desulfurization-decarbonization of claim 7, wherein the two or more chemical storage modules are provided in a vertically stacked configuration.

9. The modular desulfurization-decarbonization apparatus of claim 1, wherein the chemical storage module comprises a hinged and spring-loaded floor opening.

10. The modular apparatus desulfurization-decarbonization of claim 1, wherein the desulfurizing and decarbonizing reactor module comprises a desulfurizer and a decarbonizer; wherein the decarbonizer comprises a CO.sub.2-lean gas outlet; wherein the outlet is coupled to a ship exhaust funnel.

11. The modular apparatus desulfurization-decarbonization of claim 1, wherein the apparatus comprises: a port-side desulfurizing and decarbonizing reactor module; a starboard-side desulfurizing and decarbonizing reactor module; a port-side equipment module; a starboard-side equipment module; a port-side chemical storage module; and a starboard-side chemical storage module.

12. The modular apparatus desulfurization-decarbonization of claim 1, wherein each module is housed within a distinct standard ISO shipping container.

13. The modular apparatus desulfurization-decarbonization of claim 12, wherein a size of each shipping container is independently selected from the group consisting of 10 ft., 20 ft., 40 ft., 20 ft. high cube, and 40 ft. high cube.

14. The modular desulfurization-decarbonization apparatus of claim 1, wherein the equipment module comprises a recirculation tank; wherein the recirculation tank comprises a segregated spent sulfite tank.

15. The modular desulfurization-decarbonization apparatus of claim 1, further comprising two or more chemical storage modules; wherein the two or more chemical storage modules are provided in a vertically stacked configuration.

16. The modular apparatus desulfurization-decarbonization of claim 1, wherein each module is housed within a distinct standard ISO shipping container; wherein a size of each shipping container is independently selected from the group consisting of 10 ft., 20 ft., 40 ft., 20 ft. high cube, and 40 ft. high cube.

17. A modular desulfurization-decarbonization apparatus for removing contaminants from exhaust gas comprising: a desulfurizing and decarbonizing reactor module; an equipment module; and a chemical storage module; wherein the apparatus comprises: a port-side desulfurizing and decarbonizing reactor module; a starboard-side desulfurizing and decarbonizing reactor module; a port-side equipment module; a starboard-side equipment module; a port-side chemical storage module; and a starboard-side chemical storage module.

18. A method for removing CO.sub.2 and SO.sub.2 from an exhaust gas stream using a modular desulfurization-decarbonization apparatus, the method comprising the steps of: a) directing the exhaust gas stream into a desulfurizing and decarbonizing reactor module comprising a desulfurizer and decarbonizer; b) bringing the exhaust gas stream into contact with a first liquid reagent in the desulfurizer and absorbing into the reagent at least a part of the SO.sub.2 of the exhaust gas stream such that the gas stream is depleted in SO.sub.2 and the reagent is enriched in SO.sub.2; c) bringing the SO.sub.2-depleted gas into contact with a second liquid reagent in the decarbonizer and absorbing into the reagent at least a part of the CO.sub.2 of the SO.sub.2-depleted gas such that the gas stream is depleted in both SO.sub.2 and CO.sub.2 and the second reagent is enriched in CO.sub.2; and d) exhausting the SO.sub.2- and CO.sub.2-depleted gas to the atmosphere.

19. The method of claim of claim 18, further comprising controlling gas and liquid transfer from an equipment module.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is an illustration of a control louver damper installed inside duct connected to the top of an existing ship exhaust funnel. This damper intercepts exhaust gas flow in the duct and diverts at least a portion of the exhaust gas through exhaust gas conduits.

[0028] FIG. 2 depicts an embodiment of a desulfurizing and decarbonizing reactor module that includes a desulfurizer and a decarbonizer separated by a mist eliminator.

[0029] FIG. 3 depicts an embodiment of a modular a desulfurizing and decarbonizing apparatus that includes a desulfurizing and decarbonizing reactor module, an equipment module, and four chemical storage modules.

[0030] FIG. 4 illustrates a hinged and spring-loaded floor opening for a chemical storage module.

[0031] FIG. 5 depicts an embodiment of a modular a desulfurizing and decarbonizing apparatus that includes a desulfurizing and decarbonizing reactor module, a recirculation tank module, an equipment module, six spent chemical storage modules, and two fresh chemical storage modules.

[0032] FIG. 6 depicts a duct-side flexible expansion joint coupling a gas inlet to the inside of a container side flange that allows for sliding along slots and enables connecting or disconnecting of the inlet from the flange.

DETAILED DESCRIPTION

[0033] Disclosed herein is a modular apparatus and method for the capture of emissions from diesel engines. The method involves absorption of SO.sub.2 and CO.sub.2 using custom-designed modules. The modules may each be housed within an ISO standard size shipping container. Because the modules are housed within standard shipping containers, the modules may be installed on container ships with minimal modification to the ship. For other types of ships (tanker, vehicle transport, cruise and other), the same equipment may be installed in containers or in other shells, depending on the configuration of each vessel.

[0034] In some aspects, the method disclosed herein involves removal of exhaust gas SO.sub.2 emissions prior to removal of CO.sub.2. This feature allows ship owners currently using expensive low sulfur diesel to revert to cheaper high sulfur diesel, for which the marine engines were originally designed, while achieving compliance with 2020 SO.sub.2 emission regulations.

[0035] In some aspects, the method involves the use of a modular apparatus that comprises a desulfurizing and decarbonizing reactor module, an equipment module, and a chemical storage module. In some aspects, the modular apparatus is divided into a symmetrical system whereby exhaust gas is split and diverted to port and starboard sides of a ship. The port exhaust gas is processed using a port-side desulfurizing and decarbonizing reactor module, a port-side equipment module, and a port-side chemical storage module. The starboard exhaust gas is processed using a starboard-side desulfurizing and decarbonizing reactor module, a starboard-side equipment module, and a starboard-side chemical storage module. By dividing the modules into port- and starboard-side units, the total apparatus weight can be distributed evenly on port and starboard sides of the ship.

[0036] The modules may be permanently installed with a ship, or may be removably installed. In some aspects, the desulfurizing and decarbonizing reactor and equipment modules are permanently installed, and the chemical storage modules are removably installed. This arrangement allows for rapid removal and replacement of chemical storage modules housing spent reagents, while the reactor and equipment modules remain on the ship. Removable modules may be fitted with quick-connect and disconnect components to allow rapid module removal and installation in designated shipboard locations. In some embodiments, a module is fitted with pump-in and pump-out flanges with valves for feed and discharge of fresh and spent reagents and make-up water. Modules may be fitted with ducting, dampers with actuators, quick-connect and disconnect entrance and discharge gas hoods and vane distribution assemblies for gas conveyance and control. In some aspects, ducts and/or piping is fitted with expansion joints to allow for duct and piping movement in heavy seas.

[0037] The methods disclosed herein employ one or more chemical reagents to absorb SO.sub.2 and CO.sub.2 in a custom-designed, modular system installed in a set of modular containers. The modular system can include one or more stages of a desulfurizer reactor (for SO.sub.2 capture) and a decarbonizer reactor (for CO.sub.2 capture), custom-engineered mass transfer packing specifically designed for SO.sub.2 and CO.sub.2 capture, reagent hold tanks for storage of the fresh and spent chemical reagents, a system of recirculating pumps and piping to convey fresh reagent to distribution headers located above the packing, and reagent outlets, trays and valves to distribute reagent uniformly over the surface of the packing. In some aspects, the packing has been extensively tested for the capture of SO.sub.2 and CO.sub.2. The modular system may further include blowdown pumps, piping, valves, and related components like fittings and flanges to remove the reaction products and convey these to a spent chemical storage tank or tanks. Spent chemicals may be sold or regenerated. In some aspects, the modular system includes a ship- or land-based regeneration system for collection and transfer of reclaimed reagents and/or for production of pure CO.sub.2. In some aspects, the modular system includes instrumentation to control, measure, and record process parameters in various areas of the decarbonizer, desulfurizer, and optional regeneration systems. In some aspects, an equipment module includes one or more of a Programmable Logic Controller (PLC), Human Machine Interface (HMI), and Supervisory Control and Data Acquisition (SCADA) device to automatically control process parameters. The equipment module may include equipment to record performance data, transmit selected data to a cloud-based storage device to allow remote monitoring and troubleshooting, and enable a dedicated control panel in the ship bridge to allow manual intervention of the equipment in the event of a system problem. A core and recurring feature of the apparatus and methods disclosed herein is the emphasis placed on capturing SO.sub.2 and CO.sub.2 without disruption to ship or port operations.

A. Process Flow Sequence

[0038] Exhaust gas from a ship engine is discharged to the atmosphere from a funnel located above the upper deck of the vessel. In the modular desulfurization-decarbonization apparatus depicted in FIG. 1, control louver damper 110 is installed inside duct 100 connected to an existing exhaust funnel. This damper intercepts exhaust gas flow in the duct and diverts at least a portion of the exhaust gas through exhaust gas conduits 120 to the desulfurizer and decarbonizer system. The degree to which exhaust gas is diverted is controlled by modulating the angle of the louvers. When the damper is in the fully open position, the exhaust gas reverts to normal discharge from the funnel to the atmosphere. The modular desulfurization-decarbonization apparatus can be programmed to fully open the louvers in the event of a malfunction. The louvers can also be manually controlled remotely or from the ship bridge. The damper is a louver design with multiple blades. The angle of the blades determines the volume of gas diverted to the desulfurization-decarbonization system, and may be automatically modulated by the PLC to vary this flow volume as needed. This modulation may be conducted slowly, so as to not affect back pressure on the ship engine.

[0039] With the damper closed, 100% of the exhaust gas is directed through exhaust gas conduits 120 equally to the starboard and port sides of the ship. On each side, the exhaust gas enters an essentially identical system of modular contaminant-removal containers. Distributing the essentially identical modular containers equally on each side helps minimize ship roll along its longitudinal axis.

[0040] An embodiment of a desulfurizing and decarbonizing reactor module 210 is depicted in FIG. 2. The reactor module includes exhaust gas inlet 220. Exhaust gas travels through inlet 220 into a first desulfurizer section 230. The exhaust gas is contacted with a first liquid reagent, e.g., a NaOH solution that dissolves SO.sub.2 and reduces exhaust gas temperature to its adiabatic saturation temperature. SO.sub.2 reacts with water to form H.sub.2SO.sub.3, which in turn is converted to NaHSO.sub.3.sup.− and Na.sub.2SO.sub.3.sup.2− in the alkaline environment. The resulting SO.sub.2-enriched liquid flows vertically downward to a sulfite section of a recirculation tank. When the gas has passed through the desulfurizer, almost 100 percent of the SO.sub.2 has been captured, even if the fuel used in the engine is high sulfur diesel with more than 3.5 percent sulfur content.

[0041] The SO.sub.2-lean gas then passes through optional mist eliminator 250. The mist eliminator serves to remove any sulfite-containing droplets that may otherwise be entrained in the gas passing into the decarbonizer, and drains into the liquid flowing to the recirculation tank. The mist eliminator resides between the desulfurizer and decarbonizer components.

[0042] The SO.sub.2-lean gas next enters decarbonizer 240 located within reactor module 210. The decarbonizer and desulfurizer are physically separated from each other. In the decarbonizer, intimate contact occurs between the SO.sub.2-lean gas and a second liquid reagent. In some embodiments, the second liquid reagent is a solution of NaOH. CO.sub.2 in the gas dissolves into the second liquid reagent, forming Na.sub.2CO.sub.3 and NaHCO.sub.3. The resulting CO.sub.2-enriched liquid flows vertically downward to a carbonate section of a recirculation tank. The desulfurizer and/or the decarbonizer may be fitted with packing that promotes intimate contact between exhaust gas and liquid reagent. In some embodiments, greater than 90 percent of the CO.sub.2 in the gas is removed in the decarbonizer. The resulting SO.sub.2- and CO.sub.2-lean gas exits module 210 through exhaust gas outlet 260. The SO.sub.2- and CO.sub.2-lean gas passes through an exhaust duct to the existing ship funnel downstream of control louver damper, or through a distinct funnel and is exhausted to the atmosphere.

[0043] The embodiment depicted in FIG. 3 includes desulfurizing and decarbonizing reactor module 310, equipment module 320, and chemical storage modules 330, 340, 350, and 360. First reagent line 380 is coupled to desulfurizer of reactor module 310 (connection not depicted for clarity) and provides desulfurizer with first reagent. Second reagent line 390 is coupled to decarbonizer of reactor module 310 (connection not depicted for clarity) and provides decarbonizer with second reagent. Equipment module 320 feeds spent reagent through blowdown line 370 to chemical storage modules 330, 340, 350, and 360. The hinged and spring-loaded floor and matching roof openings in storage modules 330, 340, 350, and 360 are more clearly depicted in FIG. 4. The storage modules include a floor-opening 420 with a solid flap 410 that may be in an open or closed position. Solid flap 410 is connected to a liquid-level switch at or near the top of the storage module. When spent reagent is transferred to chemical storage modules 330, 340, 350, and 360 in FIG. 3, the floor- and roof-openings in modules 330, 340, and 350 are in an open position. The floor opening in module 360 is in a closed position. Upon module 360 becoming filled with spent reagent, the open floor in module 350 would be switched to a closed position, effectively sealing the floor of module 350. This allows module 350 to be filled with spent reagent that travels through open floors and roofs of modules 330 and 340.

B. Desulfurizer Technology

[0044] The SO.sub.2 in the gas entering the desulfurizer dissolves in and reacts with an alkaline reagent (e.g., NaOH or KOH) contained in and added from dedicated reagent storage tanks. The SO.sub.2 is converted into Na.sub.2SO.sub.3 in the desulfurizer. This reagent is recirculated from a sulfite section of a recirculation tank through the desulfurizer and is returned to the tank. The spent, SO.sub.2-enriched reagent contains sodium sulfite (Na.sub.2SO.sub.3), sodium bisulfite (NaHSO.sub.3), and sodium sulfate (Na.sub.2SO.sub.4). The reactions in the desulfurizer include:

2NaOH+SO.sub.2.fwdarw.Na.sub.2SO.sub.3+H.sub.2O

Na.sub.2SO.sub.3+SO.sub.3+H.sub.2O.fwdarw.2NaHSO.sub.3

[0045] A small amount of Na.sub.2SO.sub.4 may be formed, depending on the pH of the recirculating reagent. The pH of the liquid reagents may be adjusted by addition of NaOH, and may be carefully controlled by the PLC within a selected operating band defined by the engine fuel sulfur, engine load, and other parameters.

C. Decarbonizer Technology

[0046] When the exhaust gas leaves the desulfurizer and mist eliminator, it passes through the decarbonizer. The reactions that occur in the decarbonizer include:

CO.sub.2+H.sub.2O.fwdarw.H.sub.2CO.sub.3

H.sub.2CO.sub.3+NaOH.fwdarw.Na.sup.++HCO.sub.3.sup.−+H.sub.2O

HCO.sub.3.sup.−+NaOH.fwdarw.Na.sup.++CO.sub.3.sup.2−+H.sub.2O

[0047] The CO.sub.2 in the gas reacts with the water in the second liquid reagent to form carbonic acid (H.sub.2CO.sub.3), which then reacts with NaOH (contained in and added from dedicated tanks) to form a mixture of sodium bicarbonate (NaHCO.sub.3) and sodium carbonate (Na.sub.2CO.sub.3). The carbonate and bicarbonate are in equilibrium depending on the pH of the reagent, and these reactions are reversible. By careful control of pH by the PLC, this equilibrium may be shifted to the formation of sodium bicarbonate to ensure there is no off-gassing of CO.sub.2 in the decarbonizer. The CO.sub.2-enriched reagent is then returned to the recirculation tank.

D. NaOH Regeneration

[0048] The apparatus disclosed herein may be configured to regenerate NaOH from Na.sub.2CO.sub.3. NaOH regeneration may be performed in a dedicated regeneration module. The Na.sub.2CO.sub.3 produced by CO.sub.2 capture may be reacted with widely available and inexpensive calcium hydroxide (Ca(OH).sub.2). The reaction is:

Na.sub.2CO.sub.3+Ca(OH).sub.2.fwdarw.2NaOH+CaCO.sub.3

[0049] The regenerated NaOH is a clear liquid and may recovered by decanting from precipitated calcium carbonate (CaCO.sub.3) solids with the aid of a clarifier, centrifuge, or other commonly used device. The regenerated NaOH may be re-used in the desulfurizing and decarbonizing method described herein. Collected CaCO.sub.3, also known as limestone, may be sold for use in the chemical and other industries.

[0050] NaOH may also be regenerated by thermal decomposition of Na.sub.2CO.sub.3. The initial product is solid sodium oxide (Na.sub.2O). The reaction is:

Na.sub.2CO.sub.3.fwdarw.Na.sub.2O+CO.sub.2

[0051] The CO.sub.2 product is in the form of a gas, and may be collected and compressed for storage in low pressure tanks. The gaseous CO.sub.2 may be sold for the manufacture of various chemicals, including biofuels, or for use in carbonated beverages and industrial scale greenhouses.

[0052] The solid Na.sub.2O may then be collected and hydrated to produce NaOH. The reaction is

Na.sub.2O+H.sub.2O.fwdarw.2NaOH

[0053] The regenerated NaOH may be used on the shop as a decarbonizing and/or desulfurizing reagent.

[0054] NaOH may also be regenerated from Na.sub.2SO.sub.3 by reacting the Na.sub.2SO.sub.3 with widely available and inexpensive calcium hydroxide (Ca(OH).sub.2). The reaction is:

Na.sub.2SO.sub.3+Ca(OH).sub.2.fwdarw.2NaOH+CaSO.sub.3

[0055] The regenerated NaOH is a clear liquid and may recovered by decanting from by settling the calcium sulfite (CaSO.sub.3) solids in a clarifier, centrifuge, or other commonly used device. Alternatively, the CaSO.sub.3 may be oxidized after collection of NaOH by reducing the pH to produce calcium sulfate (CaSO.sub.4), also known as gypsum. This is widely used in the production of wallboard, used in construction.

EXAMPLES

[0056] The following examples are included to demonstrate preferred embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.

[0057] The embodiment depicted in FIG. 5 includes twenty-four modules, with twelve port-side modules and twelve starboard-side modules. This embodiment may be employed in a ship powered by a 12,000 horse-power (hp) diesel engine, for example. Only one container column, e.g., the starboard-side, is depicted for clarity, however, it is understood that this embodiment includes two columns of container modules, with the starboard-side containers mirroring the port-side containers.

[0058] The ship's exhaust gas is routed to desulfurization and decarbonization module 510. Fresh reagent from chemical storage modules 508 and 509 is used to desulfurize and decarbonize the exhaust gas. Decontaminated exhaust gas is routed from desulfurization and decarbonization module 510 and vented to the atmosphere. Spent reagent from module 510 flows downward into a recirculation tank in module 511. Recirculation tank may be housed within an equipment module that includes control systems, or the recirculation tank may be housed within a discrete module. In the embodiment depicted in FIG. 5, module 512 is a equipment module that does not house a recirculation tank.

[0059] Blowdown of spent reagent, e.g., Na.sub.2CO.sub.3 in solution, is pumped from the recirculation tank in module 511 to the top of chemical storage module 501. Floor gates in chemical storage modules 501-506 are open at the start of system operation and the floor gate in chemical storage module 507 is closed. Spent reagent travels through chemical storage modules 501-506 and fills chemical storage module 507 first. When the spent reagent level has reached the top of chemical storage module 506, a level sensor and switch at this location releases the spring-loaded gate, which closes firmly against a flexible seal, for example, ethylene propylene diene terpolymer, and prevents draining into chemical storage module 507. This process may continue until chemical storage module 501 is filled. The spring-loaded gate's flexible seal ensures there is no leakage when unloading the containers. Each container may be provided with an inner wall to contain any liquid in the unlikely event of leaks. Spent chemical storage modules 501-507 and empty fresh chemical storage modules 508 and 509 may be unloaded with replacements loaded in port.

[0060] The modular design disclosed herein minimizes the time required to unload and load designated containers when the ship has docked in port. Gas duct quick-connects and disconnects are described in FIG. 6. Piping, electrical, and instrument wiring may be routed inside mating manifolds inside and outside of each container, minimizing the number of conduit runs needed for each container. The mating manifolds may employ quick-connect and disconnect flanges. Use of these features will allow port staff to complete connections and disconnections in significantly less time than the duration of docking in port. Containers can be unloaded without pumping out of their contents, for example when a small ship is fitted with the modular apparatus disclosed herein. Alternatively, for large ships that include multiple columns of containers, flanged connections can be provided on containers to allow pumping out of spent reagent and replenishment with fresh reagent and makeup water. The containers to be unloaded and loaded may be located at the top of the container column in order to simplify removal and replacement.

Additional Embodiments

[0061] Embodiment 1: A modular desulfurization-decarbonization apparatus for removing contaminants from exhaust gas comprising: a desulfurizing and decarbonizing reactor module; an equipment module; and a chemical storage module.

[0062] Embodiment 2: The modular apparatus of embodiment 1, further comprising an exhaust gas conduit coupled to the desulfurizing and decarbonizing reactor module.

[0063] Embodiment 3: The modular apparatus of embodiment 1, wherein the desulfurizing and decarbonizing reactor module comprises a desulfurizer and a decarbonizer.

[0064] Embodiment 4: The reactor module of embodiment 3, wherein the desulfurizer is upstream of the decarbonizer.

[0065] Embodiment. 5: The reactor module of embodiment 3, wherein the desulfurizer comprises a first liquid reagent distribution header.

[0066] Embodiment 6: The first liquid reagent header of embodiment 5, wherein the first liquid reagent distribution header comprises one or more liquid reagent outlets.

[0067] Embodiment 7: The reactor module of embodiment 3, wherein the desulfurizer comprises an exhaust gas inlet coupled to the exhaust gas conduit.

[0068] Embodiment 8: The reactor module of embodiment 3, wherein the desulfurizer comprises an SO.sub.2-lean gas outlet.

[0069] Embodiment 9: The reactor module of embodiment 3, wherein the desulfurizer comprises a SO.sub.2-lean gas duct coupled to the SO.sub.2-lean gas outlet.

[0070] Embodiment 10: SO.sub.2-lean gas duct of embodiment 9, further comprising a mist eliminator.

[0071] Embodiment 11: The reactor module of embodiment 3, further comprising at least one SO.sub.2-lean gas fan.

[0072] Embodiment 12: The reactor module of embodiment 3, further comprising at least one first liquid reagent transfer pump.

[0073] Embodiment 13: The reactor module of embodiment 3, wherein the decarbonizer comprises an SO.sub.2-lean gas inlet coupled to the SO.sub.2 lean gas conduit.

[0074] Embodiment 14: The reactor module of embodiment 3, wherein the decarbonizer comprises a CO.sub.2-lean exhaust gas outlet.

[0075] Embodiment 15: The reactor module of embodiment 3, wherein the decarbonizer comprises a second liquid reagent distribution header.

[0076] Embodiment 16: The second liquid reagent header of embodiment 15, wherein the second liquid reagent distribution header comprises one or more liquid reagent outlets.

[0077] Embodiment 17: The reactor module of embodiment 3, wherein the decarbonizer comprises a CO.sub.2-lean gas outlet.

[0078] Embodiment 18: The reactor module of embodiment 3, further comprising at least one CO.sub.2-lean gas fan.

[0079] Embodiment 19: The reactor module of embodiment 3, further comprising at least one second liquid reagent transfer pump.

[0080] Embodiment 20: The reactor module of embodiment 3, wherein the decarbonizer comprises a CO.sub.2-lean gas duct coupled to the CO.sub.2-lean exhaust gas outlet.

[0081] Embodiment 21: The reactor module of embodiment 3, wherein the module optionally comprises a second decarbonizer downstream of the decarbonizer.

[0082] Embodiment 22: The equipment module of embodiment 1, wherein the equipment module comprises a first liquid reagent pump.

[0083] Embodiment 23: The equipment module of embodiment 1, wherein the equipment module comprises a second liquid reagent pump.

[0084] Embodiment 24: The equipment module of embodiment 1, wherein the equipment module comprises an SO.sub.2-enriched liquid reagent pump.

[0085] Embodiment 25: The equipment module of embodiment 1, wherein the equipment module comprises a CO.sub.2-enriched liquid reagent pump.

[0086] Embodiment 26: The equipment module of embodiment 1, wherein the equipment module comprises a recirculation tank.

[0087] Embodiment 27: The recirculation tank of embodiment 26, wherein the recirculation tank comprises a segregated spent sulfite tank.

[0088] Embodiment 28: The recirculation tank of embodiment 26, wherein the recirculation tank comprises a segregated sulfite recirculation tank.

[0089] Embodiment 29: The recirculation tank of embodiment 26, wherein the recirculation tank comprises a segregated spent carbonate tank.

[0090] Embodiment 30: The recirculation tank of embodiment 26, wherein the recirculation tank comprises a segregated makeup water tank.

[0091] Embodiment 31: The equipment module of embodiment 1, wherein the equipment module comprises a control system.

[0092] Embodiment 32: The control system of embodiment 31, wherein the control system is a Programmable Logic Controller.

[0093] Embodiment 33: The equipment module of embodiment 1, wherein the equipment module comprises a Human Machine Interface.

[0094] Embodiment 34: The equipment module of embodiment 1, wherein the equipment module comprises a Supervisory Control and Data Acquisition device.

[0095] Embodiment 35: The equipment module of embodiment 1, wherein the equipment module comprises system instrumentation.

[0096] Embodiment 36: The chemical storage module of embodiment 1, wherein the storage module comprises a segregated spent sulfite tank.

[0097] Embodiment 37: The chemical storage module of embodiment 1, wherein the storage module comprises a segregated spent carbonate tank.

[0098] Embodiment 38: The modular apparatus of embodiment 1, wherein the apparatus comprises two or more chemical storage modules.

[0099] Embodiment 39: The chemical storage module of embodiment 1, further comprising a hinged and spring-loaded floor opening.

[0100] Embodiment 40: The modular apparatus of embodiment 38, wherein the two or more chemical storage modules are provided in a vertically-stacked configuration.

[0101] Embodiment 41: The CO.sub.2-lean gas outlet of embodiment 17, wherein the outlet is coupled to a ship exhaust funnel.

[0102] Embodiment 42: The modular apparatus of embodiment 1, wherein the exhaust gas conduit is coupled to a control louver damper.

[0103] Embodiment 43: The modular apparatus of embodiment 1, wherein the control louver damper is coupled to a ship exhaust funnel.

[0104] Embodiment 44: The control louver damper of embodiment 43, wherein the damper is coupled to a port-side exhaust gas duct and a starboard-side exhaust gas duct.

[0105] Embodiment 45: The modular apparatus of embodiment 1, wherein the apparatus comprises: a port-side desulfurizing and decarbonizing reactor module; a starboard-side desulfurizing and decarbonizing reactor module; a port-side equipment module; a starboard-side equipment module; a port-side chemical storage module; and a starboard-side chemical storage module.

[0106] Embodiment 46: The modular apparatus of embodiment 1, wherein each module is housed within a distinct standard ISO shipping container.

[0107] Embodiment 47: The standard shipping containers of embodiment 46, wherein a size of each shipping container is independently selected from the group consisting of 10 ft., 20 ft., 40 ft., 20 ft. high cube, and 40 ft. high cube.

[0108] Embodiment 48: The modular apparatus of embodiment 45, wherein the port-side modules are provided in a stacked configuration on a port-side of a ship, and the starboard-side modules are provided in a stacked configuration on a starboard-side of the ship.

[0109] Embodiment 49: The modular apparatus of embodiment 1, wherein the apparatus is a port-starboard symmetrical system having an even number of each component, with at least one starboard-side component and at least one port-side component.

[0110] Embodiment 50: A method for removing CO.sub.2 and SO.sub.2 from an exhaust gas stream using a modular desulfurization-decarbonization apparatus, the method comprising the steps of

[0111] a) directing the exhaust gas stream into a desulfurizing and decarbonizing reactor module comprising a desulfurizer and decarbonizer;

[0112] b) bringing the exhaust gas stream into contact with a first liquid reagent in the desulfurizer and absorbing into the reagent at least a part of the SO.sub.2 of the exhaust gas stream such that the gas stream is depleted in SO.sub.2 and the reagent is enriched in SO.sub.2;

[0113] c) bringing the SO.sub.2-depleted gas into contact with a second liquid reagent in the decarbonizer and absorbing into the reagent at least a part of the CO.sub.2 of the SO.sub.2-depleted gas such that the gas stream is depleted in both SO.sub.2 and CO.sub.2 and the second reagent is enriched in CO.sub.2; and

[0114] d) exhausting the SO.sub.2- and CO.sub.2-depleted gas to the atmosphere.

[0115] Embodiment 51: The method of embodiment 50, further comprising transferring the SO.sub.2-enriched reagent to an equipment module.

[0116] Embodiment 52: The method of embodiment 51, further comprising transferring the SO.sub.2-enriched reagent to a recirculation tank within the equipment module.

[0117] Embodiment 53: The method of embodiment 52, further comprising transferring the SO.sub.2-enriched reagent to a segregated spent sulfite tank within the recirculation tank.

[0118] Embodiment 54: The method of embodiment 50, further comprising transferring the SO.sub.2-enriched reagent to a chemical storage module.

[0119] Embodiment 55: The method of embodiment 50, further comprising transferring the CO.sub.2-enriched reagent to an equipment module.

[0120] Embodiment 56; The method of embodiment 55, further comprising transferring the CO.sub.2-enriched reagent to a recirculation tank within the equipment module.

[0121] Embodiment 57: The method of embodiment 56, further comprising transferring the CO.sub.2-enriched reagent to a segregated spent carbonate tank within the recirculation tank.

[0122] Embodiment 58: The method of embodiment 50, further comprising transferring the CO.sub.2-enriched reagent to a chemical storage module.

[0123] Embodiment 59: The method of embodiment 50, wherein the exhaust gas stream is divided into a port-side exhaust gas stream and a starboard-side exhaust gas stream.

[0124] Embodiment 60: The method of embodiment 59, wherein a control louver damper coupled to a ship exhaust funnel divides a ship exhaust gas stream into the port-side exhaust gas stream and the starboard-side exhaust gas stream.

[0125] Embodiment 61: The method of embodiment 59, wherein the port-side exhaust gas stream is directed to a port-side desulfurizing and decarbonizing reactor module.

[0126] Embodiment 62: The method of embodiment 59 wherein the starboard-side exhaust gas stream is directed to a starboard-side desulfurizing and decarbonizing reactor module.

[0127] Embodiment 63: The method of embodiment 62, further comprising transferring starboard-side SO.sub.2-enriched reagent to a starboard-side equipment module.

[0128] Embodiment 64: The method of embodiment 62, further comprising transferring port-side SO.sub.2-enriched reagent to a port-side equipment module.

[0129] Embodiment 65: The method of embodiment 62, further comprising transferring starboard-side SO.sub.2-enriched reagent to a starboard-side chemical storage module.

[0130] Embodiment 66: The method of embodiment 62, further comprising transferring port-side SO.sub.2-enriched reagent to a port-side chemical storage module.

[0131] Embodiment 67: The method of embodiment 62, further comprising transferring starboard-side CO.sub.2-enriched reagent to a starboard-side equipment module.

[0132] Embodiment 68: The method of embodiment 62, further comprising transferring port-side CO.sub.2-enriched reagent to a port-side equipment module.

[0133] Embodiment 69: The method of embodiment 62, further comprising transferring starboard-side CO.sub.2-enriched reagent to a starboard-side chemical storage module.

[0134] Embodiment 70: The method of embodiment 62, further comprising transferring port-side CO.sub.2-enriched reagent to a port-side chemical storage module.

[0135] Embodiment 71: The method of embodiment of embodiment 50, further comprising controlling gas and liquid transfer from an equipment module.

[0136] Embodiment 72: The method of embodiment 71, wherein controlling gas and liquid transfer is controlled by a control system housed within the equipment module.

[0137] Embodiment 73: The method of embodiment 59, wherein a port-side equipment module controls port-side gas and liquid transfer and a starboard-side equipment module controls starboard-side gas and liquid transfer.

[0138] Embodiment 74: The method of any of embodiments 50 to 73, wherein each module is housed within a distinct standard ISO shipping container.

[0139] From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.