GB2608578A - Methods and related systems for processing an exhaust stream of a ship engine for safe disposal at sea - Google Patents

Abstract

A method of processing a ship engine exhaust by splitting the exhaust stream 2 into a wet 6 and a dry 14 stream using a hydrophobic membrane condenser 5, passing the wet stream 6 through either a fuel emulsification 9 or contaminant removal stage 26, and removing 15 non carbon dioxide CO2, Dinitrogen N2 and Dioxygen O2 contaminants from the dry stream 14. A first aspect discloses preparing the dry stream 14 by further separating the dry stream 14 into a Carbon rich stream 19 and a Nitrogen/Oxygen rich stream 18 and mineralising 23 the Carbon rich stream 19 for disposal. A second aspect discloses feeding the dry stream 14 alternately between two Calcium batteries based on a charge/discharge cycle of the batteries and releasing mineralised Calcium Carbonate CaCO2 for disposal.

Description

Title: Methods and related systems for processing an exhaust stream of a ship engine for safe disposal at sea

Field of Invention.

The present invention relates generally to the fields of ship engine exhaust management and carbon emission reduction. More specifically, the present invention relates to a method of separating the components of a ship engine exhaust into useful and safely disposable elements.

Background

The carbon emissions due to ship engines and their effect on the pH levels of the ocean are well known problems. Onboard carbon capture and conversion solutions for vessels have been limited both by economic viability and the limited space available on such the ships themselves, often requiring additional onshore infrastructure which would have to be implemented at ports worldwide for the solutions to be effective.

Since the 1970's liming has been practiced on a large scale in Sweden to mitigate acidification and several thousand lakes and streams are limed repeatedly. A self-regulating carbonate buffering system would help keep the ocean's pH constant by maintaining an equilibrium between the four forms of dissolved carbon dioxide: the gas itself, carbonate ions, bicarbonate ions and carbonic acid.

If the carbon emissions produced by ship engines burning fossil fuels could be converted into such an aqueous solution both problems would be solved. It is within this context that the present invention is provided.

Summary

The present disclosure provides a method and related systems for processing an exhaust stream of a ship engine for safe disposal at sea, the method comprising in sequential stages passing the exhaust gas stream through a hydrophobic membrane condenser to remove the water content, then a gas separation membrane to isolate the carbon dioxide content, then converting carbon dioxide gas thus isolated to carbonate ions in aqueous solution and precipitating calcium carbonates and carbonate hydrates for disposal at sea.

The method combines the technologies of on-board fuel emulsification, membrane separation of flue gas into water and CO2, and conversion of CO2 into calcium carbonate for disposal at sea (Carbon Capture Machine) to create an innovative solution to the carbon emissions crisis for ship engines.

The present invention thus relates to a system that will allow for known technologies to be brought together to allow the exhaust stream of an internal combustion engine to be processed into electricity and calcium carbonate neither of which are greenhouse gasses but beneficial products vis a vis climate change.

The invention is a method of producing and utilising a changed state of matter (eg. water electric power, calcium carbonate) from the exhaust gas of an combustion engine/turbine that is modular in design and proceeds by first passing the exhaust stream through a heat exchanger to cool the exhaust stream to the ambient temperature for passing to a hydrophobic membrane condensing device (5). The removed heat can be utilised as an auxiliary power source like a Turbosteamer (4) or thermo-electric generator. From there the gas stream is passed to a hydrophobic membrane device (5).

Condensed water (with contaminants) from the retent side of the membrane (5) is then passed to a computer controlled valve to divide the water into a stream for passing back to the engine using on-board fuel emulsification and a stream for passing to a post treatment unit to produce potable water.

Alternatively to or alongside fuel emulsification cooled water vapour and carbon dioxide exhaust can be passed back to the combustion chamber as exhaust gas recycling separately and in proportions that provide an optimum oxidant. (EGR a technology well known to those skilled on the art).

The remaining gas stream which has passed through the hydrophobic membrane (5) is then passed through a pre-treatment unit to remove contaminants (SOx NOx ect.) The resulting treated flue gas is passed through a gas separation membrane (6) unit to separate it into a CO2 rich stream and a N2/ 02 rich stream. The N2/02 rich stream is then passed to the local atmosphere.

The CO2 rich gas stream is then passed to a carbon dioxide to calcium carbonate reactor (7) and the mineralised calcium carbonate produced by it is disposed of at sea helping neutralize acidic waters.

In an alternative to the primary embodiment the CO2 rich gas stream is passed through a stack of charged electrochemical plates. Essentially a large, specialized battery that absorbs carbon dioxide from a gas stream passing over its electrodes as it is being charged up, and then releasing the gas as it is being discharged (8). In operation, the device would alternate between charging and discharging, with feed gas being blown through the system during the charging cycle, and then the pure, concentrated carbon dioxide being blown out during the discharging.

The pure CO2 is then passed to a discharge only calcium battery (9) that does not allow the CO2 to reform and that produces calcium carbonate which is mechanically or chemically harvested as it forms. For example with mechanical vibration you could gently remove the calcium carbonate from the cathode, keeping it clear for sustained reaction. Placed within an exhaust stream, such a system could continuously remove CO2 emissions, generating electricity and producing calcium carbonate.

This exhaust system is in eight main parts: Post combustion cooling of exhaust. ( Eg. turbo steamer, wESP, thermo-electric generator.); Separating H2O from cooled gas stream using a hydrophobic membrane condenser; Recycling some of the water reclaimed by the exhaust to the engine in the form of on board fuel emulsification and treating some of the reclaimed water for use in the ships water supply; Passing the nitrogen/ CO2 rich gas stream through reduced (reduced in size because the gas stream has been reduced by removing the H2O) pollution control means (SCR,s SOX scrubbers) well known to those skilled in the art; Passing the nitrogen/ CO2 rich gas stream through a Gas Separation Membrane to separate it into an N2/02 rich stream and a CO2 rich stream; Passing CO2 stream to a CO2 to Calcium Carbonate Reactor.(Carbon Capture machine); Passing the calcium carbonate thus produced to the sea to help reduce ocean acidification; Passing the N2/02 rich gas stream to the atmosphere.

As an alternative option to the final three steps, which may be developed upon in the future, there is an option to carry out the following process; Passing the nitrogen/ CO2 rich stream through a large, specialized battery (Polyanthraquinone hybrid electro chemical cell) that absorbs carbon dioxide from the gas stream passing over its electrodes as it is being charged up, and then releasing the gas as it is being discharged. In operation, the device would simply alternate between charging and discharging, with feed gas being blown through the system during the charging cycle, and then the pure, concentrated carbon dioxide being blown out during the discharging; Passing the pure CO2 produced to a calcium based / CO2 discharge only battery that does not allow the CO2 to reform, one that produces calcium carbonate mechanically or chemically harvesting the calcium carbonate as it forms. Applying a vibrating device and passing the calcium carbonate thus produced to the sea to help reduce ocean acidification.

Brief Description of the Drawings

Various embodiments of the invention are disclosed in the following detailed description and accompanying drawings.

FIG.1 illustrates a block and flow diagram of an example set of steps in accordance with a first embodiment of the present disclosure.

FIG.2 illustrates a block and flow diagram of an alternative example set of steps in accordance with a second embodiment of the present disclosure.

Common reference numerals are used throughout the figures and the detailed description to indicate like elements. One skilled in the art will readily recognize that the above figures are examples and that other architectures, modes of operation, orders of operation, and elements/functions can be provided and implemented without departing from the characteristics and features of the invention, as set forth in the claims.

Detailed Description and Preferred Embodiment

The following is a detailed description of exemplary embodiments to illustrate the principles of the invention. The embodiments are provided to illustrate aspects of the invention, but the invention is not limited to any embodiment. The scope of the invention encompasses numerous alternatives, modifications and equivalent; it is limited only by the claims.

Numerous specific details are set forth in the following description in order to provide a thorough understanding of the invention. However, the invention may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the invention is not unnecessarily obscured.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any combinations of one or more of the associated listed items. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well as the singular forms, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.

On-board fuel emulsification is a commercially available system that produces a fuel saving and a large reduction in NOx emissions it has not gone mainstream until now because it would require ships to carry a large tank of water or have an on-board desalination plant. Other combustion enhancing technologies utilising water are known to those skilled in the art and could utilises the water produced. (eg. Fully vapouried fuel, using water to provide an extra power stroke in a six stroke engine and using electrolysis to turn pure water into oxygen and hydrogen for using as a catalyst in the combustion process to overcome disadvantages such as ignition delay and the decrease of power for emulsified fuel.) Emulsified fuel gives better overall performance but it does have a disadvantage of producing ignition delay The ignition delay in a diesel engine is defined as the time interval between the start of injection and the start of combustion. This delay period consists of (a) physical delay, wherein atomisation, vaporization and mixing of air fuel occur and (b) of chemical delay attributed to pre-combustion reactions. The technology of a catalytic reforming reaction is introduced to the combustion of the emulsified oil. A small quantity of hydrogen generated by a catalytic reforming reaction can effectively overcome disadvantages of ignition delay and the decrease of power for emulsified fuel because of the large coefficient of diffusion and heat conduction for hydrogen, which increase the rate of heat transport to the surface of droplets. Therefore, it can reduce specific fuel consumption far more than that of emulsified fuel without catalytic reforming reaction. The availability of purified water allows for hydrogen carbon cleaning technology to be used along with emulsified fuel thus producing a fuel saving of 20% . Referring to FIG.1, a block and flow diagram of an example set of steps in accordance with a first embodiment of the present disclosure is shown.

Downstream of the engine (1) the exhaust system (2) passes to cooling means (3) well known to those skilled in the like heat exchangers, turbo steamers and thermo-electric generators from there the exhaust stream is passed to a Hydrophobic membrane condensing device (5) via pipe (4). The water contained in a saturated gas is condensed and recovered in the retentate side of the membrane module, thanks to the hydrophobic nature of the membrane and to the lower temperature at which the condenser is operated. The dehydrated gases, instead, pass through the membrane in the permeate side. When the water condenses in the membrane module the hydrophobic nature of the membrane prevents the penetration of the liquid into the pores. The water is then past via pipe (6) to a computer controlled water recycling valve (7) which recycles water in controlled amounts via pipe (8) to a fuel emulsification device (9) where it is mixed with fuel from pipe (10) the on board emulsified fuel is then passed via pipe (11) to a computer controlled valve (12) where it is mixed with CO2 gas and air in computer controlled amounts. It is then passed to the engine via pipe and injectors (13).Water from water Recycling Valve (7) is passed via pipe (25) to Post Treatment Unit (26) to be processed by methods well known to those skilled in the art into potable water for the ships drinking water supply. From there the water is passed via pipe (39) to an electrolysis device (40) that splits the water into oxygen and hydrogen from there the hydrogen is passed via pipe (41) and the oxygen is passed via pipe (42) to a Computer controlled Fuel/Oxygen/Hydrogen mixing device (43) before passing to the fuel mix via pipe (44) to the combustion chamber of engine (1).

The exhaust gas from the permeate side of the membrane (5) is passed via pipe (14) to the reduced pollution control devices (15) and the pollution free exhaust gas (N2, 02, CO2) is passed through a gas separation membrane(17) which divides the gas stream into a N2O2 rich stream and a CO2 rich stream. The N2O2 rich stream is passed to the atmosphere via pipe (18). The CO2 rich stream is passed via pipe (19) to a computer controlled Exhaust Gas Recirculation Valve (20) which divides the gas stream into an EGR stream for passing a proportion of the CO2 via pipe (21) to act as oxidant in the combustion process and a stream passed via pipe (22) to a carbon capture machine (23) for conversion into calcium carbonate for safe disposal at sea. The calcium carbonate solution is passed to safe disposal means via pipe (24). The CO2 in pipe (21) is passed to EGR valve (12) where it is mixed with air and on-board emulsified fuel. The exhaust gas from the permiate side of the membrane (5) is passed via pipe (14) to the reduced pollution control devices (15) and the pollution free exhaust gas (N2, 02, CO2) is passed via pipe 16 to a gas separation membrane(17) which divides the gas stream into a N2O2 rich stream and a CO2 rich stream. The N202 rich stream is passed to the atmosphere via pipe (18). The CO2 rich stream is passed via pipe (19) to a computer controlled Exhaust Gas Recirculation Valve (20) which divides the gas stream into an EGR stream for passing a proportion of the CO2 via pipe (21) to exhaust gas/emulsified fuel valve (12) to act as oxidant in the combustion process and a stream passed via pipe (22) to a carbon capture machine (23) for conversion into calcium carbonate for safe disposal at sea. The calcium carbonate solution is passed to safe disposal means via pipe (24). The CO2 in pipe (21) is passed to EGR valve (12) where it is mixed with air and on-board emulsified fuel before being passed to pipe /fuel injectors to the fuel feed to the engine (13).

Referring to FIG.2, a block and flow diagram of an alternative example set of steps in accordance with a second embodiment of the present disclosure is shown.

In the alternative embodiment Figure 2 the water extraction using membrane (3) through to using water recaptured from the exhaust is the same. The gas however is handled differently it first passed through a stack of charged electrochemical plates (31) The device is essentially a large, specialized battery that absorbs carbon dioxide from a flue gas stream passing over its electrodes as it is being charged up, and then releases the gas as it is being discharged. In operation, the device would simply alternate between charging and discharging, feed gas being blown through the system during the charging cycle, and then the pure, concentrated carbon dioxide being blown out during the discharging.

As the battery charges, an electrochemical reaction takes place at the surface of each of a stack of electrodes. These are coated with a compound called polyanthraquinone, which is composited with carbon nanotubes. The electrodes have a natural affinity for carbon dioxide and readily react with its molecules in the airstream or feed gas, even when it is present at very low concentrations. The reverse reaction takes place when the battery is discharged during which the device can provide part of the power needed for the whole system -and in the process ejects a stream of pure carbon dioxide. The whole system operates at room temperature and normal air pressure.

The gas stream is divided by valve (29) and sent down pipes (30) to send to two hybrid batteries (31) which will be alternately in charge and discharge mode. the output from this is passed via pipes (32) to a computer controlled recombining exhaust gas recycling valve (33) which divides the gas stream into an EGR stream (35) for passing a proportion of the CO2 via pipe (35) to exhaust gas/emulsified fuel valve (39) to act as oxidant in the combustion process and a stream passed via pipe (34) discharge only calcium battery (36) here a mechanical vibrating device (37) gently removes the solid from the cathode, keeping it clear for sustained reaction, If placed within an exhaust stream, such a system could continuously remove CO2 emissions, generating electricity and produce calcium carbonate at the same time. From the calcium battery the calcium carbonate is passed to disposal at sea means via pipe (38).

The basic invention is to use batteries as a method of removing CO2 from a gas stream as they can provide some or all of the power to remove the CO2 from the gas stream. Until now CO2 removal from a gas stream has been energy expensive. The batteries should be in a gas stream with a temperature as close to their ambient temperature as possible.

A discharge-only setup -addresses the problem of allowing CO2 gas to reform by never allowing the gaseous CO2 to re-form. If by mechanical vibration you could gently remove the solid from the cathode, keeping it clear for sustained reaction, If placed within an exhaust stream, such a system could continuously remove CO2 emissions, generating electricity and produce calcium carbonate at the same time. Converting captured CO2 into calcium carbonate can potentially be achieved by electrochemical processes -in this case, a process in which chemical reactions release electrical energy, as in the discharge of a battery in particular, those that occur inside lithium-0O2 batteries.

The system would be based on calcium, a material that's not yet well-developed for battery applications. If the calcium-0O2 setup works as predicted, the solid that forms would be calcium carbonate which could be safely disposed of at sea.

Unless otherwise defined, all terms (including technical terms) used herein have the same meaning as commonly understood by one having ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The disclosed embodiments are illustrative, not restrictive. While specific configurations of the system for providing a virtual event space coordinated with a real world event space have been described in a specific manner referring to the illustrated embodiments, it is understood that the present invention can be applied to a wide variety of solutions which fit within the scope and spirit of the claims. There are many alternative ways of implementing the invention.

It is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.

List of Reference Numerals 1 Marine Diesel engine 2 Exhaust system 3 Cooling means (eg. thermo electric generators, turbo steamers, wESPs) 4 Pipe from cooling means to Hydrophobic Membrane Condenser Hydrophobic Membrane Condenser 6 Condensed water pipe 7 Condensed water recycling valve.

8 Water pipe from valve to emulsification device 9 Fuel emulsification device Fuel tank and fuel pipe to emulsification device 11 Emulsified fuel pipe to exhaust gas recycling valve 12 Exhaust gas recirculation/emulsified fuel valve 13 Fuel feed to computer controlled fuel mixing device 14 Flue gas (N2 02 CO2) feed to pollution control devices.

Reduced pollution control devices ( Selective catalytic Reduction Unit, Sox, Scrubber, Particulate Trap ect.) 16 Contamination free N2, 02, CO2,pipe from pollution control devices (15) to gas separation membrane (17) 17 Gas separation membrane 18 N2 02 exhaust gas to output to atmosphere 19 CO2 pipe from Gas separation membrane(17) to Exhaust gas recirculation valve (20) Exhaust gas recirculation valve 21 CO2 Exhaust gas recirculation feed pipe from Exhaust gas recirculation control valve (20) to exhaust gas/emulsified fuel valve (12) 22 CO2 pipe from Exhaust gas recycling valve (20) to Carbon capture machine (23) 23 Carbon Capture Machine.

24 Calcium carbonate output for disposal at sea.

Pipe from condensed water recycling valve (7) to post treatment unit (26) 26 Post treatment unit for potable water.

28 Contamination free N2, 02, CO2, pipe from pollution control devices (15) to separation valve (29) 29 Separation valve Separation Pipes 31 Hybrid Battery Stack in charging/discharging mode 32 Charging discharging /discharging pipes 33 Computer controlled reintegration exhaust gas recirculation valve 34 Pure CO2 feed pipe from EGR valve (33) to discharge only Calcium Battery (36) CO2 feed pipe from EGR valve (33) to Exhaust gas/emulsified fuel valve (12) 36 Discharge only Calcium Battery 37 Mechanical vibrating device 38 Pipe from Mechanical vibrating device for Calcium carbonate output disposal at sea 39 Pipe from post treatment unit (26) to electrolysis device (40) Electrolysis device 41 Hydrogen pipe from electrolysis device (40) to Computer controlled fuel mixing valve(43) 42 Oxygen pipe from electrolysis device (40) to Computer controlled fuel mixing valve(43) 43 Computer controlled Fuel/Oxygen/Hydrogen mixing device 44 Pipe from Computer controlled fuel mixing valve (43) to Engine (1)

Claims (7)

1. Claims What is claimed is: 1. A method of processing an exhaust stream of a ship engine, the method comprising the steps of: a. separating the exhaust stream into a dry stream and a wet stream using a hydrophobic membrane condenser; b. funnelling the wet stream to a fuel emulsification device or a post-treatment unit configured to remove contaminants to produce potable water; and either: c. treating the dry stream to remove non CO2, N2, and 02 contaminants; and either: d. preparing the dry stream for safe disposal at sea by: d.i. Separating the dry stream into a carbon rich stream and a nitrogen and oxygen rich stream; d.ii. mineralising the carbon rich stream for disposal at sea;ORe. passing the dry stream through a valve that alternatively feeds the dry stream to two separate calcium batteries formed of stacks of charged electrochemical plates by: e.i. alternately funnelling the dry stream between the two batteries according to a charge/discharge cycle of the batteries; and e.ii. releasing a resultant mineralised calcium carbonate deposit from the batteries at sea.
2. 2. A method according to claim 1, wherein the method further comprises the step of first cooling the exhaust stream to an ambient temperature.
3. 3. A method according to claim 2, wherein the cooling is performed by passing the exhaust stream through a heat exchanger.
4. 4. A method according to claim 1, wherein at least a portion of the wet stream is used for fuel emulsification, and the method further comprises passing an output of the fuel emulsification device to a ship engine fuel intake.
5. 5. A method according to claim 1, wherein step (c) involves removing Sox and NOx contaminants.
6. 6. A method according to claim 1, wherein step (b) is implemented by a computer-controlled valve.
7. 7. A method according to claim 1 that passes potable water produced by step b) to a catalytic reforming reaction devise that splits the water into an oxygen and hydrogen stream for passing back to the combustion chamber.