Carbon capture system and method

Abstract

A carbon dioxide capture system for removing carbon dioxide from an exhaust gas stream, comprising: a gas pump configured to induce a flow of the exhaust gas into a heat exchanger, and thereby cool the exhaust gas; a reactor coupled to the heat exchanger to receive the cooled exhaust gas, the reactor including a volume of solvent to react with carbon dioxide in the exhaust gas to form a byproduct rich fluid, and a drier coupled to the reactor to receive the byproduct rich fluid and evaporate water from the byproduct rich fluid to produce a solid byproduct and water vapor; wherein the heat transferred from the exhaust gas stream by the heat exchanger is used to operate the drier, so as to produce the solid byproduct. Other aspects relate to mixing of gas with solvent using a perforated plate to generate bubbles, and sequestration using the byproduct as a component of concrete.

Description

CARBON CAPTURE SYSTEM AND METHODTechnical Field

[0001] This invention relates to a carbon capture system, and more particularly to a system for capturing carbon dioxide, from exhaust gas streams or other sources, and related methods.Background of the Invention

[0002] The release of carbon dioxide (CO2) and other greenhouse gases by human activities is recognised as being the main cause of global warming. One response is to reduce the combustion of fossil fuels, and to modify other activities such as agriculture and forestry, in order to reduce the man-made production of greenhouse gases.

[0003] However, in the short term, the cessation of fossil fuel use is unlikely. Further, in order to return the atmosphere and climate to a stable condition, it is likely to be necessary to actively remove carbon dioxide (and potentially other greenhouse gases) at the point of emission as well as directly from the atmosphere. As a consequence, carbon capture, utilization, and permanent storage is an active area of endeavour.

[0004] One strategy to mitigate greenhouse gas emissions is Carbon Capture, Utilization, and Storage (CCUS). CCUS involves first capturing carbon dioxide from point sources, for example blast furnaces, fossil fuel fired power stations, diesel or gas engines and gas extraction I compression facilities, which typically emit a large amount of carbon dioxide, or directly from the atmosphere. The captured carbon dioxide is then further concentrated through drying and removing other impurities, compressed, transported, and injected into appropriate geological formations for long-term storage. The capture process is energy intensive, and unless the storage structure is nearby, the associated costs and carbon footprint for transport, pipelines, refrigeration and pumping are very high.

[0005] Some approaches to capturing some or all of the carbon dioxide emitted by stationary and mobile fossil fuel engines and stationary industrial processes have been proposed. An advantage of such approaches is that the exhaust gases have a relatively high concentration of carbon dioxide, relative to free air or a more diffuse exhaust stream.

[0006] Published patent application US20240050891 A1 discloses a system for removing carbon dioxide from a flow of gas. The system includes a venturi eductor configured to receive the flow of gas, a flow of an alkaline solution at a predetermined pH range, a reaction chamber, and an output of a metal carbonate slurry or solution to an evaporator.

[0007] It is an object of the present invention to provide a greenhouse gas capture system and method which is efficient and effective in operation.Summary of the Invention

[0008] In a first broad form, the present invention provides a carbon dioxide capture and sequestration system, in which part of the heat from the input gas stream is utilized to operate a dryer, so as to produce a solid carbon containing output from a liquid or slurry output.

[0009] In another broad form, the present invention provides a carbon dioxide capture and sequestration system, in which the carbon dioxide is captured in a CaO solution and forms a CaCO3 byproduct, and the byproduct is incorporated into a concrete product to sequester the carbon dioxide.

[0010] According to one aspect, the present invention provides a carbon dioxide capture system for removing carbon dioxide from an exhaust gas stream, comprising: a gas pump configured to induce a flow of the exhaust gas into a heat exchanger, and thereby cool the exhaust gas;a first reactor coupled to the heat exchanger to receive the cooled exhaust gas, the first reactor including a volume of solvent and configured and dimensioned to operatively provide sufficient reaction time to facilitate transfer of a substantial part of the carbon dioxide in the exhaust gas into the solvent, and to allow for reaction of the carbon dioxide to form a byproduct rich fluid, and to release spent exhaust gas;a drier coupled to the first reactor and configured to receive the byproduct rich fluid and evaporate water from the byproduct rich fluid to produce a solid byproduct and water vapor;wherein the heat transferred from the exhaust gas stream by the heat exchanger is used to operate the drier, so as to produce the solid byproduct.

[0011] According to another aspect, the present invention provides a method for capturing carbon dioxide from an exhaust gas stream, including at least the steps of:Providing a gas pump configured to induce a flow of the exhaust gas into a heat exchanger, and thereby cool the exhaust gas;Providing a first reactor coupled to the heat exchanger to receive the cooled exhaust gas, the first reactor including a volume of solvent and configured and dimensioned to operatively provide sufficient reaction time to facilitate transfer of a substantial part of the carbon dioxide in the exhaust gas into the solvent, and to allow for reaction of the carbon dioxide to form a byproduct rich fluid, and to release spent exhaust gas;providing a drier coupled to the first reactor and configured to receive the byproduct rich fluid and evaporate water from the byproduct rich fluid to produce a solid byproduct and water vapor;The method including inducing a flow of exhaust gas through the heat exchanger, mixing the cooled exhaust gas with the solvent, capturing carbon dioxide in the byproduct in the solvent, and drying the byproduct rich fluid to produce a solid byproduct, wherein the heat transferred from the exhaust gas stream by the heat exchanger is used to operate the drier, so as to produce the solid byproduct.

[0012] According to a further aspect, the present invention provides a carbon dioxide capture system for removing carbon dioxide from an exhaust gas stream, comprising: a gas pump configured to induce a flow of the exhaust gas into a heat exchanger, and thereby cool the exhaust gas;a reactor coupled to the heat exchanger to receive the cooled exhaust gas, the reactor including a volume of solvent and configured and dimensioned to operatively provide sufficient reaction time to facilitate transfer of a substantial part of the carbon dioxide in the exhaust gas into the solvent, and to allow for reaction of the carbon dioxide to form a byproduct rich fluid, and to release spent exhaust gas;a drier coupled to the reactor and configured to receive the byproduct rich fluid and evaporate water from the byproduct rich fluid to produce a solid byproduct and water vapor;wherein the reactor further includes a perforated screen for generating bubbles of the cooled exhaust gas within the solvent in the reactor so as to increase capture of carbon dioxide.

[0013] According to a further aspect, the present invention provides a method for capturing and sequestering carbon dioxide from an exhaust gas stream, including at least the steps of:Providing a gas pump configured to induce a flow of the exhaust gas into a heat exchanger, and thereby cool the exhaust gas;Providing a first reactor coupled to the heat exchanger to receive the cooled exhaust gas, the first reactor including a volume of solvent and configured and dimensioned to operatively provide sufficient reaction time to facilitate transfer of a substantial part of the carbon dioxide in the exhaust gas into the solvent, and to allow for reaction of the carbon dioxide to form a byproduct rich fluid, and to release spent exhaust gas;Providing a drier coupled to the first reactor and configured to receive the byproduct rich fluid and evaporate water from the byproduct rich fluid to produce a solid byproduct and water vapor;the method including inducing a flow of exhaust gas through the heat exchanger, mixing the cooled exhaust gas with the solvent, capturing carbon dioxide in the byproduct in the solvent, drying the byproduct rich fluid to produce a solid byproduct, and forming a concrete product including the solid byproduct, so that the carbon dioxide is sequestered within the concrete product.

[0014] The present invention further encompasses byproduct material made according to the method or system of the present invention, and a cement or concrete product incorporating the byproduct material.

[0015] Suitable implementations of the present invention allow for the efficient removal of carbon dioxide from exhaust gases, and produce a byproduct which can be readily used for long term sequestration of carbon.

[0016] Implementations of the invention help in the reduction of greenhouse gas emissions and particulate matter from the exhaust from coal industry; mining; transport industry such as truck emissions; heavy vehicles; ships; diesel generators; commercial buildings; residential homes; and industrial emissions.Brief Description of the Drawings

[0017] Illustrative embodiment of the present invention will now be described with reference to the accompanying figures, in which:

[0018] Figure 1 is a schematic block diagram showing a first implementation of a carbon capture and sequestration system according to the present invention;

[0019] Figure 2 is a control system block diagram for an implementation of the present invention.

[0020] Figure 3 is a perspective view of Reactor 2 according to a first implementation of the present invention;

[0021] Figure 4 is an exploded view of Reactor 2 of Figure 1;

[0022] Figure 5 shows data from concrete testing utilizing the byproduct from the carbon capture and sequestration system;

[0023] Figure 6 Shows the C02 offset by the lifecycle of 1 Ton of Active chemical, Utilizing a Low CO2 Grade Chemical, with an energy efficient manufacturing process;

[0024] Figure 7 Shows the CO2 offset by the lifecycle of 1 Ton of Active chemical, Utilizing a Low CO2 Grade Chemical, with an energy inefficient manufacturing process;

[0025] Figure 8 Shows the CO2 offset by the lifecycle of 1 Ton of Active chemical, Utilizing a Standard CO2 Grade Chemical, with an energy efficient manufacturing process;

[0026] Figure 9Shows the CO2 offset by the lifecycle of 1 Ton of Active chemical, Utilizing a standard CO2 Grade Chemical, with an energy inefficient manufacturing process;

[0027] Figure 10 is a schematic block diagram showing a second embodiment of a carbon capture and sequestration system according to the present invention;

[0028] Figure 11 is a flow diagram of one implementation of the software used to control the system;

[0029] Figure 12 is a block diagram illustrating the overall process of an implementation of the present invention; andDetailed Description of the invention

[0030] The present invention will be described with reference to specific modes of implementation and specific applications. However, it will be appreciated that the general principle of the present invention is of wide scope and may be applied to many different situations. The example provided is intended as illustrative of possible implementation, and not limitative of the scope of the invention disclosed. The exemplary uses relate to use of the present invention in relation to a stationary generator of greenhouse gas rich exhausts, such as a diesel generator or other stationary engine or generator. However, the present invention may be employed, with suitable modification to the implementation, to a wide range of applications, for example land vehicles, particularly heavy transport and other heavy vehicles; marine applications; stationary industrial processes; coal, gas or oil powered electricity generators; commercial, industrial and residential buildings; or other exhaust or flue gas uses. It is applicable to combustion processes using any kind of fossil fuel, for example gasoline, diesel, oil, heavy fuel oil, coal, lignite, natural gas, LPG, propane, butane, methane or any other fossil fuel or carbon based renewable fuels, for example biomass, bio waste, bio based synthetic fuels, or Efuels.

[0031] With suitable modifications, for example a concentration system and pressurisation components, the present invention may also be applied to applications with less concentrated carbon dioxide or other target gas streams.

[0032] The present invention is primarily described with reference to removing CO2 from an exhaust stream. Implementations of the present invention may also have the effect of removing other contaminants, for example particulates, from the exhaust stream as the exhaust passes through the capture fluid. Sulphur oxides and nitrogen oxides, and other combustion products, may also be removed, either intentionally or as a byproduct of the capture process. The system and method of the present invention should not be understood as limited to the specific capture fluids disclosed herein.

[0033] Implementations of the present invention seek to remove some or all of the CO2 from the gas stream which is treated. The term remove is intended to encompass both complete removal, and partial removal from the gas stream to be treated. The exact extent of removal will be a function of many factors in the practical system, for example flow rates and gas stream composition.

[0034] Moreover, the system and process according to this implementation do not require steam or hot utility for regeneration of the capture solvent, making it an ideal technology for diesel generators and engines. Power consumption is of critical concern for carbon dioxide capture systems, as there is limited power available from the combustion of fossil fuels and this power is dedicated to supplying power to the intended purpose of the machine. Additionally, steam is not always available in the vicinity of diesel generators or on moving vehicles. For mobile combustion sources, power consumption, foot print, and weight of equipment are major issues. By not requiring regeneration, the power consumption, footprint and the weight of the equipment are reduced significantly, making it more suitable for use in these applications.

[0035] Figure 12 provides an overview of the steps in the operation of an implementation of the present invention. The system is designed to treat exhaust gas from a combustion source by directing the gas through a reaction tank containing a reactive chemical medium. As the exhaust gas flows through the tank, a chemical interaction occurs between the gas and the medium, enabling reduction or removal of selected components from the gas stream. In preferred versions, the system operates continuously by renewing the chemical medium during operation.

[0036] Exhaust gas 201 exiting the combustion source typically contains particulates and is at a high temperature. Before entering the reaction tank, the system will typically include:a particulate-removal stage 202 to capture or reduce solid particles, and• a gas-cooling stage 203to lower the temperature to a suitable range for the reaction process.

[0037] These stages protect downstream components and stabilise operating conditions for the reaction tank. The gas colling stage is conveniently carried out by a heat exchanger.

[0038] After conditioning, the exhaust gas is fed into a gas-pumping subsystem 204. This subsystem generates the pressure and flow required to draw in the exhaust gas, and move the gas through the reaction tank 207. The gas-pumping unit204 can preferably adjust its operating level based on load, thereby controlling:gas flow rate,gas residence time within the reaction tank, andpressure conditions in the system.

[0039] The reaction tank 207 is the primary location where the exhaust gas interacts with the chemical medium.

[0040] The reaction tank includes:

[0041] An inlet for receiving conditioned gas,

[0042] A reactive chemical medium, which may be added in the form of a slurry, solution, or suspension (e.g., alkaline chemical mixture),

[0043] A gas-chemical contacting zone 206, in which the gas is introduced into or across the chemical medium,

[0044] Internal or external recirculation, which may be used to improve mixing and maintain uniform chemical distribution,

[0045] An outlet 208 for discharging treated gas.

[0046] Inside the tank, the target gas component (for example, CO2or other acidic species) reacts with or is absorbed by the chemical medium. The size, shape, and internal design of the tank may vary depending on the specific process requirements ofthe particular combustion system to which the invention is applied, as will be understood by those skilled in the art.

[0047] To maintain continuous operation, the system includes:a chemical addition inlet 206, where fresh chemical medium or precursor material is introduced into the reaction tank, anda chemical discharge outlet, through which a portion of the used or reacted chemical medium is removed.

[0048] This maintains the reactive capacity of the chemical medium without stopping system operation, so that continuous operation can be achieved. Fresh chemical can be added by the inlet based on operating time, throughput, or control conditions. The discharged material will include the by-product, which is dried and collected, as will be explained below.

[0049] Figure 2 illustrates a control architecture for an implementation of a system according to an aspect of the present invention. A main control unit coordinates the system. This may be any suitably configured processor, for example, a programmable logic controller (PLC) with suitable I / O cards. It is configured to:Operate the gas-pumping subsystem,Control circulation of the chemical medium,Control the rate of chemical addition and discharge,Execute operational logic and safety functions.

[0050] The control unit and associated software ensures stable gas flow, maintains chemical availability, and prevents operation outside the desired limits.

[0051] At 230, treatment of exhaust gas is enabled or disabled, preferably responsive to the operation of the combustion source, e.g. a diesel generator.

[0052] At 232, the gas pumping unit is controlled to adjust the flow rate and pressure through the reaction tank.

[0053] At 233, the circulation and mixing inside the reaction tank are controlled to maintain gas / chemical contact.

[0054] At 234, addition of further chemicals are controlled, as the reactive components are spent, and the removal of solution containing the byproduct is controlled.

[0055] During operation, the system proceeds through the following stages:1. Exhaust IntakeExhaust gas enters the particulate-removal stage.2. Gas ConditioningGas is cooled to the appropriate working temperature.3. Gas PumpingThe gas-pumping subsystem drives the conditioned gas toward the reaction tank.4. Gas-Chemical InteractionThe gas enters the reaction tank and is brought into contact with the reactive chemical medium.Gas-liquid contact may be achieved by sparging, bubbling, spraying, or other suitable means.5. Chemical RenewalFresh chemical medium is added while an equivalent volume of spent medium is discharged.This maintains consistent reactivity during continuous operation.6. Clean Gas DischargeThe treated gas is released from the outlet of the reaction tank and discharged to the final outlet.

[0056] Implementations of the present invention provide a number of advantages. The system allows for continuous operation, with more reagents added as required, and ongoing production of the byproduct. The system can be readily added to existing exhaust systems, and can handle variable exhaust gas flows. Further, the effective management of gas-chemical interactions provides for improved control of operating conditions.

[0057] The term ‘capture fluid’ is used to describe the reactive chemical medium, the water in which it is carried, and the byproduct formed progressively in the fluid. Thus, the composition will vary over time and with the level of reaction, and may be a solution in water, or a slurry or suspension, depending on the circumstances.

[0058] Connecting the carbon capture and sequestration system (301,401) to the exhaust of the combustion source is simple. The piping should be designed so that it issuitable to avoid backflow of capture fluid, and so that the operation of the carbon capture and sequestration system will minimise, ideally to zero, back pressure on the combustion process through the use of a gas pump, such as a venturi scrubber, and / or use of a blower. Retrofitting of the carbon capture and sequestration system (301,401 ) to the point source emitter can be accomplished through simple connections that physically mate to the exhaust source and standard electrical connections to the output of the electrical generator or utility. The connecting pipe size will of course vary depending on the size of the combustion source exhaust. The connection pipe can be made from steel, high temperature composites or any other suitable material for the high temperature application.

[0059] Physically connecting the carbon capture and sequestration system (301,401 ) to the diesel generator may not be necessary. In suitable implementations, it may be possible to just pull the exhaust in through the induced draft from the venturi or other gas pump without the need to connect. It would be possible to pull in atmospheric air with the exhaust and then perform direct air capture and point source capture simultaneously.

[0060] Retrofit of the carbon capture and sequestration system according to this implementation of the present invention (301,401) is not detrimental to the operation and output of a diesel engine or diesel generator, provided the carbon capture and sequestration system (301,401) is correctly connected. If the capacity of the capture system is lower than the gas exhaust flow of the diesel generator, then only a portion of the exhaust will be processed for CO2 capture, the remaining will be vented to the atmosphere, for example by using a three-way valve.

[0061] The invention also provides a method of retrofitting the carbon capture and sequestration system (301,401) to another device, a machine, a plant or a vehicle producing carbon dioxide-containing pollution such as, a point source, and further relates to an engine which has been so modified.Component Concentration Value (during test) Value (expected in DG)CO2 Vol% (wet) 7.60 2-12N2 Vol% (wet) 77.01 60-7002 Vol% (wet) 10.50 9-18H2O Vol% (wet) 4.80* 2-13

[0062] A specific example will now be described. The exhaust is from a stationary diesel generator. The gas composition of the exhaust input to the carbon capture and sequestration system (301,401 ) is provided below. These values were measured directly out of the exhaust pipe from the generator.Table 1

[0063] *This value is estimated based on the observed dew point of the exhaust gas and was not directly measured during the test. The output values achieved after passage through the carbon capture and sequestration system (301,401) were as follows:Table 2Component Value Method For Determining DuringTest21 O to 220°C Direct MeasureExhaust Gas Temperature IntoCooling System39 to 41 °C Direct MeasureExhaust Gas Temperature Outof Cooling System3.5 m3 / minVolumetric Flow Rate of Calculated based on change Exhaust Gas Into Cooling in density between hot and System cold exhaust gas2.25 m3 / minVolumetric Flow Rate of Estimated based on Venturi Exhaust Gas Out of Cooling Performance Curves and System solvent system operating pressure / flow4.45[CO2] Direct Measurement

[0002] Direct Measurement

[0064] The engine exhaust temperature was about 210 to 220°C and the exhaust pressure at the outlet of the tailpipe of the generator was between 0-3 in. w.c. throughout the test. The engine exhaust gas flow rate was about 2.25 m3 / min at 40°C.

[0065] As shown in Figure 1 and Figure 11, practical examples of the present invention provide a carbon capture and sequestration system (301,401) that includes an exhaust gas measuring system, a spray drying chamber, a particle separator, an exhaust gas heat exchanger, a venturi scrubber, a byproduct separator, one or two reactors, level controllers for the reactors, a backpressure regulator blower and associated cooler, a reactor coolant pump, a solvent cooler and associated pump, a chemical addition chamber, electrical system, and instrumentation and controls.

[0066] The exhaust gas measuring system (301,402) is used to determine the flow rate of carbon dioxide (and possibly NOx, SOx, CO and particulate matter) coming out of the tailpipe of the diesel generator. In order to determine the efficacy of the system and perform carbon accounting, it is critical to obtain accurate measurements of the exhaust gas properties and flow rates. The exhaust gas measuring system measures exhaust gas properties coming out of the diesel generator tailpipe and at the exit of the carbon capture and sequestration system. The properties being measured at the outlet of the generator are; exhaust gas temperature, CO2 (and possibly NOx, Sox, CO and particulate matter) concentration, and volumetric flow rate. The property(s) being measured at the outlet of the carbon capture and sequestration system are CO2 (and possibly NOx, Sox, CO and particulate matter) concentration. These measurements will be read in real time and the software will use them to calculate the mass flow rate of CO2 (and possibly NOx, Sox, CO and particulate matter) both into and out of the system. These values can then be integrated throughout the run time of the diesel generator to determine the mass of CO2 (and possibly NOx, Sox, CO and particulate matter) captured and the total reduction in CO2 (and possibly NOx, Sox, CO and particulate matter) emissions through the carbon capture and sequestration system.

[0067] The carbon capture and sequestration system (301,401) further includes a mechanism to remove the byproduct created during the carbon capture process from the system, in order to allow the system to run continuously without the need to shutdown the system to remove accumulated byproduct. This feature utilizes a byproduct drying device to dry byproduct using heat from the exhaust stream coming out of the diesel generator and subsequently remove and store the byproduct. In the present invention, a spray drier (303, 403) is utilised in conjunction with a cyclone separator (303,404) or other equivalent particle separation device, such as an interior impactor, charged plate separation device or other method and collection vessel (see Figure 2).

[0068] The spray drier (303, 403) takes a flow of byproduct rich solvent from the Byproduct Preparation Device (307, 416). This flow enters the spray drier and is sprayed through a nozzle to atomize the liquid and byproduct directly into the exhaust gas. In a preferred form, the gas is provided as the waste heat from the heat exchanger, positioned to cool the incoming exhaust gas from the combustion prior to processing. In certain iterations the spray drier will also use a flow of gas from the blower (312, 406) to both preheat the incoming byproduct slurry and to aid in atomization of the slurry. As the atomized spray enters the exhaust gas in the spray drying chamber (303, 403), the water will evaporate, leaving behind only dry byproduct. This dry byproduct continues to flow with the exhaust gas into a particulate separator (cyclone, inertial, charged plate, or equivalent) (304, 404) where the solid particulates are removed from the exhaust stream and stored in a byproduct collection vessel. The particle separation device may also consist of multiple steps and chambers to allow separation of the byproduct into different streams, based on particle size. By further separating into multiple particle classes, the byproduct can be used in more specific cement or chemical applications.

[0069] The flow rate of byproduct through the spray drier system is controlled based on temperature of the exhaust stream exiting the particle separation device. Flow is regulated to maintain temperature between about 80-125C to ensure that the spray drying process does not become saturated with liquid water. The spray drier (303, 403) operates continuously and the flow rate of liquid / byproduct mix is varied, based on the exhaust gas temperatures entering and leaving the spray drier (303, 403). The top end of flow for the exemplary system, using a 30 kVA generator will be 10 g / s byproduct and 6.7 g / s water. This is based on the maximum CO2 flow through the system at 100% capture efficiency.

[0070] Chemical storage and byproduct storage for the device may be accomplished through, for example, custom containers that interface directly with the carbon capture and sequestration system (301, 401 ). The containers will include a method for the system to recognize that they are properly installed, such as an RFID or equivalent method. This will ensure that there is always a fresh supply of chemical to feed to the system, as well as ensuring that there is always a container available to retain the byproduct, to prevent byproduct exiting the particle separation device (4) from being unknowingly released to the environment. The chemical feed and byproduct storage containers will be identical in design, allowing the operator to remove the spent byproduct, move the chemical storage vessel into its’ place and load new chemicals utilizing the same operational method. The containers may also include mechanisms for powder handling, such as vibratory or auger components. The containers will be designed to be re-used following emptying of byproduct to minimize overall waste generated by the system.

[0071] There are several benefits to drying byproduct in-situ and removing in powder form vice slurry / wet form. The first of which is the weight of the byproduct is significantly reduced. By reducing the weight of the byproduct, the CO2 emissions required to ship the byproduct from the jobsite are reduced. Most, if not all, of the energy utilized to evaporate water from the byproduct is provided directly from the engine exhaust. Thisgreatly reduces the power requirements to achieve a dry byproduct. For example, about 17 kW of thermal power are available on a 30 kW diesel generator that can be taken from the exhaust gas that otherwise would have been dissipated to ambient without any method to utilize. The motive force to drive the gas through the spray dryer is the venturi scrubber.

[0072] By using the venturi scrubber to drive the fluid, there is no need to add an additional blower, thereby reducing the overall power requirements and complexity of the system. Also, there may be some amount of active chemical mixed in with the byproduct slurry, which could be utilized to add an additional carbon capture step to the system. Lastly, drying the byproduct in-situ allows the byproduct to exit the carbon capture and sequestration system (301, 401) in a commercially viable form, without the need to send to a processing facility to prepare the byproduct. By creating the final form prior to exiting the system, the carbon lifecycle is greatly improved because transportation to a processing facility is not required and emissions tied to the processing of the byproduct are avoided.

[0073] The thermodynamic analysis of the spray drier is shown below.tepsrBpwte Hwt:Gpwater “ 4.18 KCpbypraduot -. S3 kJfkgKCpexhsm ^ 1.11 y>§KUot h« if wter - System Fiws^s;m&stodwst ” 42.5ototobyiwdoto: S:1 flByprod^Wwster opsfeing tempor^tiw - 11"?Cstolate w fe heal w^lahle fem enghe (C& ks e>tai^fem C to 1 KTC) Qd - ®te * s^s * J’Pi — fest®, M2S * 1, 11 * ( G - 180)gsfofe:". I7WWl s:Qc t s id® tlwi aw®r awls bl® ta th® sx s st gasmhi h the eshatisi fk roteis extern gas m r r® festers id® s rsy ^rysr1W h efeauto gaa toro oafere after the w dryerCd^late B^predyoVWatgr flew oepefety ef waste heat§afoi — msfefl * epi * (Tteit — Has.) mdfe:2 * q?2 * (Tfet — Tin) +> MdetS * 2268 ifeanange esguatfcm ta wk« for msass flow1fee of water (mdto2)rrfe’ 2 ■••• <^w-4s)w«)■>•■:;?,<'’?::::= & 7 $ / slWSiiOder h to® thermal p»er a^ilfel® tan ta efe fe a®fet te the byprstoost flow1feecp1 s to® yprofe to speech eto oepstotytotS te too w l wte ths ®petofc b®to cep&el to® waterTn te ® slurry Wrnpwtw® W«w to® ®pi®y toys®Iboi h the slwr te pe tur® after "th® spray dryerTherefore, the spray drier works without any additional heat required, provided that the ratio of water to byproduct in the slurry does not exceed.67 grams of water per gram of byproduct at maximum flow and temperature for the system. However, in certain iterations, an electric heater may be used to allow higher capacity of the spray drier across a wider operating band.

[0074] Whilst the example provided are primarily in the context of a spray drier, the heat from the input exhaust gas can equally be used to fully or partly provide the necessary heat input for other types of driers. For example, these could include a paddle drier, a fluidised bed, or a rotary drier, all using the exhaust gas heat, output through a heat exchanger, to achieve the necessary drying.

[0075] Following the particle separation device (304, 404) the exhaust gas will be about 80-125C and will have a substantially higher moisture content than when it exited the generator. In order to minimize the volumetric flow rate through the venturi scrubber and to reclaim the water removed during spray drying, the exhaust gas must be further cooled to a range of from about ambient to 60C. To perform this operation the exhaust gas heat exchanger (305, 405) is utilized. The exhaust gas heat exchanger (305, 405) according to this implementation uses an axial fan to force a flow of ambient air across a radiator to transfer thermal energy from the exhaust gas to ambient. During the cooling process, the exhaust gas will reach and fall below its dew point and the evaporated water from the solvent drying process will be condensed. This condensed water is then returned to Reactor 1 (313, 410), allowing the system to continuously operate the spray dryer, without the need to add water. This feature is particularly important for remote sites, where access to water is not available. In addition to condensing the water used in spray drying, additional water vapor that was present in the exhaust gas prior to the spray drier may be condensed, which will create an excess of water for the system that can be used for purposes such as, but not limited to; spraying a mist of water back onto the exhaust gas heat exchanger (5) to increase effectiveness of the cooler or the initial filling of the system with water in remote areas.

[0076] The system includes a venturi scrubber (306, 408) which serves multiple purposes for the system, depending on the embodiment of the invention. In the first embodiment, shown in Figure 1, the venturi scrubber performs the following functions.

[0077] First, the venturi scrubber (306) is used to maintain a state of very low, ideally zero backpressure on the engine. Maintaining zero backpressure on the engine is critical to both engine health and efficiency. If the engine is forced to operate with high backpressure, the generator will need to burn a substantially larger amount of fuel for the same power output and the temperatures and pressures felt by the engine will be much higher, thereby decreasing engine life, increasing fuel use, and increasing the maintenance cost for the generator. Second, the venturi scrubber acts as the first step in the carbon capture process. Testing performed has shown that about 10-40% of the carbon dioxide in the exhaust gas is captured inside of the venturi scrubber. Third, theventuri scrubber acts as a mixing mechanism for Reactor 1. The mixed flow of exhaust gas and capture solvent that leave the venturi scrubber is submerged under the liquid level of Reactor 1 (313) and creates a high degree of agitation within Reactor 1 (313) which aids in suspending the chemicals in the carbon capture fluid. This step is critical because the solubility of the chemicals used is very low in water, so to ensure that the chemical reaction does not become limited, it is important that the particles stay suspended in the solvent and are not allowed to settle at the bottom of the reactor. During operation of the Venturi Scrubber (306) the solvent pressure is about 120-850 kPa with about 35-190 Ipm of solvent flow. On the exhaust gas side of the venturi, -0.75 to 0.75 kPa pressure is maintained at the outlet of the generator with flow rates of about 1-4.5 m3 / min of exhaust at 25-60C.

[0078] The functions of the venturi nozzle in the second embodiment, shown in Figure 10 are as follows. First, the venturi scrubber (408) is used to create intense mixing of the exhaust gas into the capture solvent, by micronizing the bubbles into the solvent. Second, the venturi scrubber creates a pressurized environment for the reaction to occur, greatly increasing reaction rates between the solvent and CO2. Third, the venturi scrubber acts as a mixing mechanism for Reactor 1. The mixed flow of exhaust gas and capture solvent is fed into the bottom of Reactor 1 (410) and creates a high degree of agitation within Reactor 1 (410) which aids in suspending the chemicals in the carbon capture fluid. This step is critical because the solubility of the chemicals used is very low in water, so to ensure that the chemical reaction does not become limited, it is paramount that the particles stay suspended in the solvent and are not allowed to settle at the bottom of the reactor. During operation of the Venturi Scrubber (408) the solvent pressure is about 120-850 kPa with about 35-240 Ipm of solvent flow. On the exhaust gas side of the venturi, 6-105 kPa pressure is maintained at the outlet of the blower with flow rates of about.5-4.5 m3 / min of exhaust at 25-60C.

[0079] Although the description above refers to a venturi scrubber, it will be appreciated that alternative gas pumps could be used to induce exhaust gas into the system. For example, a roots blower or a side channel blower.

[0080] The carbon capture and sequestration system (301,401) contains a solvent distribution pump (318, 411 ). This pump will be a centrifugal pump or equivalent designed to supply the rated flow of solvent to the venturi scrubber (306,408), spray nozzle for the pressurized reaction chamber (310,409), and any other required solvent distribution loads. The pump will draw suction from Reactor 1 and all solvent will ultimately discharge back to reactor 1 for further distribution throughout the system.

[0081] In embodiment 1, the carbon capture and sequestration system (301,401) contains two reactors that are operated at or close to ambient pressure. The first reactor (313) serves multiple purposes for the carbon capture and sequestration (301,401) system. First, it is the primary storage tank for the solvent. Also, the first reactor (313) is where the precipitated byproduct from CO2 absorption is collected for subsequent spraydrying operations. Additionally, the mixing of the solvent occurs in the first reactor (313) to ensure the active chemicals remain suspended in the solvent. The first reactor (313) is also where pH is monitored to control the chemical dosing system (319). Finally, Reactor 1 is where condensed water is returned to the system to allow continuous use of the carbon capture and sequestration system without the need to add additional water. The flowrates are the same as for the Venturi Scrubber (306). The temperatures are typically 20 to 80°C, pressure in the chamber typically ranges from -3 to 3 kPa, and pH ranges are typically from about 10-12.

[0082] The second reactor (316) is the final step of the carbon capture and sequestration process according to this implementation. Figures 3 and 4illustrate Reactor 2 (100). Reactor 2 (100) includes generally a bottom assembly 1, a middle assembly 9, and an upper assembly 19. Pipe 30 allows for the connection of exhaust gas from the outlet of the backpressure regulator (9), and pipe 40 is where the exhaust gas monitoring system (302,402) connects. Flange 15 joins bottom assembly 1 to middle assembly 9, and flanges 7 join middle assembly 1 to upper assembly 19.

[0083] Perforated element 13 is disposed inside the bottom assembly 1 and middle assembly 9. Exhaust gas from the backpressure regulator (9) enters from pipe 30 via the opening in bottom distributor plate 5.

[0084] Perforated element 13 has a large array of openings 14. It may be formed from any suitable material, for example carbon steel or other corrosion resistant alloys, preferably corrosion resistant stainless steel. The pore diameter may be, for example, from 200 microns to 3 mm. The pore pattern is intended to provide a sufficient structure to induce and / or control bubble formation, as will be further described below. As will be apparent to those skilled in the field, a variety of different patterns and shapes are possible. In the illustrated example, the pores are diagonal with a pitch of 1.2 to 1.5 times the pore diameter. It will be understood that the shape of the element 13 as illustrated is cylindrical, may be changed to provide a different shaped but generally planar surface, for different applications of the present invention. In use, the exhaust gas enters the filter device 100 from the bottom distributor plate 5 and rises in the form of bubbles in and outside the perforated element 13. The design of perforated element 13 restricts the growth of the bubbles, so that they remain relatively small.

[0085] The gas passes through perforated element 13 and the capture fluid, and forms secondary bubbles by breaking the bubbles while exiting the top of perforated element 13. The frequent breaking and formation of bubbles helps in efficient interaction of liquid and gas, so as to increase the interaction of the target CO2 with the capture fluid.

[0086] The filter length required depends on the main vessel capacity. A minimum of 80% length of the perforated element 13 is preferably inside the capture fluid. The cylinder diameter in this implementation is preferably 60 to 80% of the inside diameter of the main vessel, in other words, of the middle assembly 9 in this implementation. It will beappreciated that the exact dimensions and construction may be varied depending upon the specific characteristics of the exhaust stream to be filtered, for example including the flow rate and volume.

[0087] According to these implementations, the carbon capture and sequestration system (301,401) contains a byproduct preparation system (307,416) to ensure the byproduct entering the spray drier is at the desired concentration, flow rate and temperature for optimal spray drier and overall system performance ( or for any alternative drier). As shown in the calculations above, the ratio of water to byproduct is critical to system performance. In order to ensure this ratio is maintained and little to no extra energy is required to dry the byproduct, the byproduct may first need to be concentrated. The byproduct concentration system will utilize the difference in density between the byproduct, active chemical and water to perform this separation. This system may, in suitable implementations, I consist of some or all of the following components; a dosing pump to control flow of byproduct slurry into the spray drier, a gravity separation system to allow the byproduct to settle at the bottom of the container away from the water and a centrifugal separator to separate the byproduct from the unused active chemical. The system may also contain an electric heater to increase the capacity of the spray drier at low generator load conditions. The system may also contain a heat exchanger to transfer heat energy from the compressed gas exiting the blower (312,406) into the slurry to increase capacity of the spray drier at low generator load conditions. The dosing mechanism may be a pump or similar device or it may be driven by the pressure from the outlet of the blower (312 / 406).

[0088] In embodiment 2, there is only a single reactor 1 (410) preferably structured as illustrated in figures 3 and 4 and described above,

[0089] In embodiment 1, the pressurized reaction chamber will be supplied with a flow of pressurized exhaust gas from the blower (312) and with a steady flow of solvent from the solvent distribution pump (318). The pressurized reactor will be arranged in a counterflow orientation, where exhaust gas flows in the bottom of

[0090] The carbon capture and sequestration system of this embodiment (301 / 401) will require a blower (312,406) to increase the pressure of the exhaust gas.

[0091] For embodiment 1, in addition to increasing the pressure of the exhaust gas, the blower will also be used to control the pressure of Reactor 1 (313) to about -3 to 3 kPag. By reducing the pressure in Reactor 1 (313) the venturi scrubber (306) will be able to move a larger flow of exhaust gas, with less solvent flow, thereby minimizing the power required to operate the venturi scrubber (306). The blower may be a regenerative blower, rotary lobe blower, ring compressor, or other gas compression method.

[0092] The primary purpose for increasing system pressure is to increase capture efficiency. As the exhaust gas flows through the venturi scrubber (306) and reactor 1(313) about 40-60% of the CO2 is captured, leaving a relatively lean concentration of CO2, making it difficult to achieve further capture, without creating a system that is too large for many applications. To increase the system capture efficiency, without the need for prohibitively large reactors and piping system, the exhaust gas will be pressurized and fed into the pressurized reaction chamber. During the compression step, the temperature of the exhaust gas will increase. The outlet temperature of the blower will range from about 10-150C above the inlet temperature. This heat energy must be removed and the system is equipped with a blower cooler (311).

[0093] In addition to raising the temperature of the exhaust gas, the compression step will also increase the vapor pressure of the water vapor in the exhaust gas. By increasing the vapor pressure, the dewpoint of the gas is lowered, which will cause water to condense during the cooling step. This water is then reclaimed and sent to the chemical addition chamber (319,415). In some iterations, this heat energy may be sent to the byproduct preparation system (307,416) to be utilized to preheat the byproduct slurry. The blower cooler will be similar in design to the exhaust gas heat exchanger (305,405) and will use an axial fan to force ambient air across a radiator to remove this heat energy. The operating pressure at the outlet of the blower will be about 7-105 kPag. In some iterations, the blower may also be used to supply a head pressure on the byproduct preparation system to induce flow into the spray drier without the need for an additional pump.

[0094] For embodiment 2 of the system, the blower serves as the mechanism to control backpressure on the engine, as well as to increase pressure of the exhaust gas to increase reaction between the solvent and exhaust gas CO2. The blower will monitor outlet pressure from the engine and will vary its speed to ensure that a state of 0 backpressure is maintained on the engine. Due to the varying speed of the blower, the outlet pressure will be maintained using a back pressure regulator (414) on the outlet of Reactor 1 to ensure that even at low flow conditions, the pressure is maintained to allow optimal CO2 capture.

[0095] The carbon capture and sequestration system (301,401) will contain a chemical addition chamber (319,415). The primary function of this chamber is to add powder form of the solvent chemicals into the system. This chamber will be fed powdered chemicals through a vibratory hopper, screw conveyor, auger, or similar device. The chemical addition chamber is also where the fresh chemical container is loaded by the operator. During operation of the carbon capture and sequestration system (301,401) the chemicals will be added into a chamber and when pH within Reactor 1 falls below a specified value, the solvent distribution pump (318,411) will be diverted to flow through the chemical addition chamber (319,415) to introduce new chemicals for CO2 absorption. Once sufficient flow has passed through the chemical addition chamber, the solvent distribution pump will return to the normal flow path, water will be drained from the chamber back into reactor 1 (313,410), and the next dose of chemicals will be fed into the system in preparation for the next chemical addition. In addition to adding chemicalsto the system, the chemical addition chamber (319,415) will also serve as a collection reservoir for condensed water vapor from the blower cooler. By collecting this water, the need to refill the system with water will be mitigated and the system can operate continuously, even in the most remote locations.

[0096] The carbon capture and sequestration system (301,401) also includes an electrical system. The electrical distribution panel will be part of the hardware to distribute power from the generator or utility to require loads in the system. The electrical system has some or all of the following components: battery, inverter, rectifier, 24V control system, E-stop, fuses, breakers, variable frequency drives, electrical panels, 12V control system and transformers. The electrical system is equipped with a mechanism to perform a safe and controlled shutdown, even if the generator is turned off or loses power without warning. The electrical system consists of a battery sized to handle the entire shutdown sequence.

[0097] The carbon capture and sequestration system (301,401) is controlled by software, as shown in Figure 11. The software regulates the pressure in the solvent circulating system. This serves to maintain a 0 backpressure state on the engine and prevents pulling a vacuum. The system pressure is varied, based on engine operating state to minimise overall power draw of the system. There is likely a smart controller that utilised lookup tables to determine the optimal operating pressure for given exhaust flow rates.

[0098] The software also regulates the cooling systems (305,405) (311,407) (314,412) (315,413). The cooling system output is modulated to control exhaust and solvent temperatures to a predetermined setpoint. This control system is used to minimise overall power draw on the system. The cooling system may have a smart control system that takes data for exhaust gas, ambient and solvent temperature and change cooling setpoints / locations for optimal power efficiency.

[0099] The software also controls the flow of byproduct slurry into the spray drier (303,403). This is done to ensure that the temperature of the exhaust does not fall below saturation temperature for the liquid content of the gas stream. If the exhaust gas temperature were to fall below saturation, liquid droplets would be formed and liquid water would be mixed with the dry powder in the particle separation device.

[0100] The software also controls the addition of chemicals to the system. When pH in reactor 1 (313,410) falls below setpoint, the flowpath of the discharge of the solvent distribution pump is changed, to add chemicals from the chemical addition chamber (319,415) into the system.

[0101] The software also regulates the speed on the blower (312,406). The blower speed will be modulated to maintain about ambient pressure on reactor 1 (313) inembodiment 1 or the diesel engine outlet pressure in embodiment 2 for Figure 2 to minimize the power required to maintain zero back pressure on the engine.

[0102] Furthermore, the software calculates reduction from the system. The software monitors CO2 inlet concentration, CO2 outlet concentration, exhaust gas flow and possibly diesel fuel burned to determine the net CO2 reduction. This software has the ability to export a report, to be used for any applicable carbon accounting requirements.

[0103] The carbon capture and sequestration system (301,401) measures temperature at the following locations: immediately coming out of the diesel generator exhaust pipe, after the exhaust gas cooler, at the discharge of the solvent pump, at the outlet of the blower and at the outlet of the blower cooler.

[0104] The carbon capture and sequestration system (301,401) also monitors pressure at the following locations: at the outlet of the generator exhaust, Reactor 1 pressure, at the outlet of the solvent distribution pump, and at the outlet of the blower. Likewise, mass flow rate of the diesel exhaust is measured at the inlet of the system.

[0105] In the present invention, there are three different chemical reaction pathways that the solvents can utilise. These three pathways are dependent on which chemical is used in the solvent. The primary chemicals in the solvent that are utilised in the present invention are CaO, MgO and / or NaOH / Na2CO3. Other chemicals can also be used and there are several identified waste streams that can be utilised in the solvent to reduce the CO2 footprint of the mixture.1st Reaction Set (CaO)CaO(s)+H2O(aq) ~ Ca(OH)2(s) (1) Ca(OH)2(s) ~ Ca2+(aq) + 2OH-(aq) (2) CO2(g) + H2O(I) ~ H2CO3(aq) ~ HCO3-(aq) + H+ ~ 2H+ + CO32-(aq) (3) Ca2+(aq) + HCO3-(aq) CaCO3(s) + H+(aq) (4) Ca2+(aq) + CO32-(aq) —> CaCO3(s) (5)2nd Reaction Set (MgO)MgO(s)+H2O(aq) ~ Mg(OH)2(s) (1) Mg(OH)2(s) ~ Mg2+(aq) + 2OH-(aq) (2)C02(g) + H20(l) ~ H2CO3(aq) ~ HC03-(aq) + H+ ~ 2H+ + CO32-(aq) Mg2+(aq) + HCO3-(aq) MgCO3(s) + H+(aq)Mg2+(aq) + CO32-(aq) MgC03(s)3rd Reaction Set (NaOH}2NaOHf^s+ CO^ Na;CO3;s.,, + (1)Na2CO3(s) + CO2(g) + H2O(g) ~ 2NaHCO3(s) (2) Na2CO3(s) + 0.6 CO2(g) + 0.6 H2O(g) ~ 0.4[Na2CO3*3NaHCO3(s)]. (3)3rd Reaction Set (NaOH)(1) 2NaOH.-w.;* CC>i:y.??Na2CO3(s) + CO2(g) + H2O(g) ~ 2NaHCO3(s) (2) Na2CO3(s) + 0.6 CO2(g) + 0.6 H2O(g) ~ 0.4[Na2CO3*3NaHCO3(s)]. (3)4th Reaction Set (Na2CO3)Na2CO3(s) + C02(g) + H20(g) ~ 2NaHCO3(s)Na2CO3(s) + 0.6 CO2(g) + 0.6 H2O(g) ~ 0.4[Na2CO3*3NaHCO3(s)]To improve the life cycle analysis, the solvent chemical composition may be combined with one or more of the following waste products: fly ash, recycled concrete, steel slag, mine tailings and phosphogypsum waste from construction demolition.

[0106] The carbon capture and sequestration system (301,401 ) may be implemented with any suitable capture solvent. A variety of such solvents are disclosed in the prior art, and with appropriate modifications any such solvent may be used in conjunction with the present capture system (301,401 ). Suitable solvents may include an aqueous solution of alkali carbonates.

[0107] There are several key advantages to locking the CO2 away in the chemical reactions above. One advantage is that there is no need to regenerate the byproduct to capture and store CO2, as used in many other carbon capture technologies. By removingthe need to regenerate and subsequently store the CO2 in liquid and / or gaseous form the energy requirement for the system is greatly reduced. The second benefit is that storage of the captured CO2 is significantly simpler. Storing CO2 in pure form requires a high energy compression system with large, energy intensive cooling systems. In addition to the lower energy requirements, there is no possibility of the captured CO2 leaking out of the system, increasing the overall capture efficiency of the system. In addition to improving the capture efficiency, the safety of the system is greatly increased. Storing CO2 in liquid form requires cryogenic storage in addition to the high pressure, about 1200 psi or greater, storage systems. In order to safely operate this sort of system, highly trained and expensive operators, safety systems and mechanical designs are required, in addition to specialty logistics operations for the safe transport of the CO2. All of these items greatly impact not only the safety and capture efficiency of systems with regeneration capability, but also ultimately increase the cost to capture CO2 for the consumer.

[0108] Another advantage of the capture solvents proposed, relative to some alternatives, is that the effectiveness of CO2 capture is not compromised by SOX and NOX impurities in the exhaust gases to be treated. For systems where the capture material is regenerated, these impurities are often unable to be removed during the normal regeneration sequence because their bonds are stronger than that of CO2. This means that over time, the capacity of regenerable CO2 capture systems is reduced and the system efficacy declines. By adding fresh chemicals for CO2 absorption to the system, this concern is mitigated for the carbon capture and sequestration system.

[0109] The carbonates may be of a single metal, or a mixture thereof.

[0110] It will further be understood that the capture fluid may be altered to target additional or alternative components. Further, in a system where (for example) different capture fluids required incompatible chemistries, the capture devices according to the present invention could be operated in a serial connection, with the output of one system as the input to a second system.

[0111] Solvent regeneration is possible for the solvents. For CaO or MgO based solvents, a green grid needs to be built for a facility or find a source of ample waste heat. The NaOH / Na2CO3 based solvents can be regenerated or can be regenerated from available waste heat from high temperature point source applications.

[0112] CaCO3, MgCO3, Na2CO3 and NaHCO3 can be filtered from the byproduct and sold as raw materials.

[0113] The byproduct that is generated by the preferred carbon capture and sequestration system is CaCO3. Analysis indicates that the byproduct material is typically composed primarily of crystalline calcium carbonate, with approximately 89.6 wt% calcite, 6.9 wt% aragonite and 3.5 wt% portlandite based on the XRD report. The balance is particulates and impurities.

[0114] CaCO3 can specifically be used as an input into green cement.

[0115] Portland cement has several environmental drawbacks, making it a significant contributor to global pollution and environmental degradation. Portland Cement production is responsible for nearly 8% of global CO2 emissions. This is primarily due to the chemical reaction (calcination) involved in converting limestone (calcium carbonate) into lime (calcium oxide), which releases large amounts of CO2. Additionally, the high heat required for this process is often generated by burning fossil fuels.

[0116] Supplementary Cementitious Materials (SCMs) are materials used in concrete to replace a portion of Portland cement, which helps reduce the environmental impact of concrete production. SCMs include industrial byproducts like fly ash, slag cement (ground granulated blast furnace slag), and silicon fume, as well as natural pozzolans which have volcanic ash or calcined clay. Incorporating SCMs into concrete products can help achieve more sustainable, cost-effective, and durable construction materials.

[0117] During trials to sequester the byproduct it was discovered that the byproduct from this carbon capture and sequestration system can be used as a direct replacement for Portland cement. Testing has been performed and validated that the byproduct is a direct replacement for Portland Cement. Data from 24 hour, 7 day and 28 day strength testing is shown in Figure 5. By replacing a proportion of the Portland Cement in the cement manufacturing process, the carbon emissions from the cement sector can be greatly reduced. Replacing Portland Cement with CaCO3 with embedded CO2 can specifically be used as an input for green cement.

[0118] A further trial using 35% CaCO3 byproduct from the present invention and 65% Portland cement, in a standard concrete formulation in cylinder moulds,, with a target strength of 40MPa, yielded results as follows:

[0119] Day 1 Day 3 Day 7 Day 2815.5MPa 34 MPa 47 MPa 64 MPa

[0120] The value of 40 MPa is that required for a noise panel wall.

[0121] Carbon capture system have difficulty achieving a fully positive life cycle analysis (LCA) due to several interconnected factors. Most carbon capture technologies, such as post-combustion capture (using solvents like amines) or direct air capture (DAC), are energy-intensive. They often require significant amounts of energy to separate, compress, and store CO2. If this energy is derived from fossil fuels, the overall emissions associated with the process may offset much of the CO2 captured. Even with renewable energy, the efficiency losses can be substantial, reducing the overall net benefit. All existing technologies have a variety of efficiency, cost, and environmental issues that prevent them from achieving a fully positive life cycle analysis (LCA). However, ongoing improvements in technology, energy sources, and policy could improve the LCA of carbon capture systems in the future.

[0122] If the product of the capture process is used in a concrete based sequestration system, then in some implementations it has a positive LCA. The advantage of having a positive life cycle analysis for a carbon capture and sequestration system is that it demonstrates the technology’s ability to reduce more greenhouse gas emissions than it generates throughout its entire lifecycle.

[0123] A life cycle analysis has been performed for Scope 1 and Scope 2 emissions for the quicklime utilized by the carbon capture and sequestration system (301 / 401) and can be seen in Figures 6-9. There are different grades of quicklime (CaO) available, all with different CO2 equivalencies in their manufacturing process. All 4 figures show the reduction in CO2 that will be incurred for every ton of quicklime utilized in the capture process. The analysis has also been performed for different system capture efficiencies and power requirements for the carbon capture and sequestration system (301,401). A summary of the analysis is shown below as well. As shown in Figures 6-9, by capturing CO2 from point source exhaust streams and utilizing the byproduct as a direct replacement for Portland Cement, the lifecycle of the process results in a net negative CO2 lifecycle for the majority of the operating domain.

[0124] Calcium oxide is generally produced by calcining limestone (whose main component is calcium carbonate) at 900-1200 degrees Celsius to produce calcium oxide and carbon dioxide. The formula is CaCO3 —> CaO + CO2, which does produce a large amount of carbon dioxide. A rough calculation shows that the production of one ton of calcium oxide produces 0.785 tons of carbon dioxide.Conventional production of quicklime commonly uses coal for burning lime. The carbon dioxide emissions generated by its combustion are between 2.5 and 3.5 tons per ton. Taking the production of 1 ton of lime as an example, theoretically, 0.1084 tons of standard fuel are required. If coal is used and calculated based on 3.7 tons of carbon dioxide emitted per ton of coal, then the carbon dioxide emitted by burning coal is approximately 0.1084x3.7 = 0.40108 tons. So in the process of producing 1 ton of calcium oxide, theoretically there will be 0.785+0.401 =1.186 tons of carbon dioxide emissions.

[0125] It is accordingly preferred that a low carbon source of quicklime is used, in order to optimise the environmental outcomes. Green CaO suppliers exist, such as Salt X and Zeql, see https: / / www.zeql.com / .

[0126] / Vet CO2 = + B) + £? - D - &2 * E + k3(rf + B)Where:A = CO2 released from energy generated to perform the calcination processB - CO2 released from limestone during the calcination processC = Additional CO2 released from the generator due to increased feet consumption from powering the carbon capture and sequestration systemD = CO2 captured by carbon capture and sequestration systemE = CO2 released during the Portland Cement manufacturing process, that is offset by the byproductkl = Applied factor to account for additional quicklime manufacturing to account for the increase In active Ingredient needed to account for additional COS released from point source due to Increase In fuel consumption.k2 = Factor to account for additional mass of CO2 embodied in the byproduct.k3 - Factor to account for capture efficiencies below 100%

[0127] It will be appreciated that those skilled in the art that the above are merely examples of how the invention may be put into practice. There are many other implementations possible, which while different in some details, would nevertheless fall within the spirit and scope of the invention.

Claims

Claims1. A carbon dioxide capture system for removing carbon dioxide from an exhaust gas stream, comprising: a gas pump configured to induce a flow of the exhaust gas into a heat exchanger, and thereby cool the exhaust gas;a reactor coupled to the heat exchanger to receive the cooled exhaust gas, the reactor including a volume of solvent and configured and dimensioned to operatively provide sufficient reaction time to facilitate transfer of a substantial part of the carbon dioxide in the exhaust gas into the solvent, and to allow for reaction of the carbon dioxide to form a byproduct rich fluid, and to release spent exhaust gas;a drier coupled to the reactor and configured to receive the byproduct rich fluid and evaporate water from the byproduct rich fluid to produce a solid byproduct and water vapor;wherein the heat transferred from the exhaust gas stream by the heat exchanger is used to operate the drier, so as to produce the solid byproduct.

2. A carbon capture system according to claim 1, wherein the reactor further includes a perforated screen for generating bubbles of the cooled exhaust gas within the solvent in the reactor so as to increase capture of carbon dioxide.

3. A carbon dioxide capture system according to claim 1 or claim 2, wherein a solid dosing system is coupled to the reactor, the dosing system being adapted to deliver a powdered reagent into the reactor, the reagent mixing with the solvent and operatively reacting with the carbon dioxide to form the by product.

4. A carbon dioxide capture system according to any one of the preceding claims, wherein a further heat exchanger is configured to receive and recondense the water vapor from the drier for re-use.

5. A carbon dioxide capture system according to any one of the preceding claims, wherein the solvent is selected from an aqueous solution of CaO, MgO, NaOH or Na2CO3, and where the byproduct includes CaC03, MgCO3, Na2CO3 or NaHCO3.

6. A method for capturing carbon dioxide from an exhaust gas stream, including at least the steps of:Providing a gas pump configured to induce a flow of the exhaust gas into a heat exchanger, and thereby cool the exhaust gas;Providing a first reactor coupled to the heat exchanger to receive the cooled exhaust gas, the first reactor including a volume of solvent and configured and dimensioned to operatively provide sufficient reaction time to facilitate transfer of a substantial part of the carbon dioxide in the exhaust gas into the solvent, and to allow for reaction of the carbon dioxide to form a byproduct rich fluid, and to release spent exhaust gas;providing a drier coupled to the first reactor and configured to receive the byproduct rich fluid and evaporate water from the byproduct rich fluid to produce a solid byproduct and water vapor;The method including inducing a flow of exhaust gas through the heat exchanger, mixing the cooled exhaust gas with the solvent, capturing carbon dioxide in the byproduct in the solvent, and drying the byproduct rich fluid to produce a solid byproduct, wherein the heat transferred from the exhaust gas stream by the heat exchanger is used to operate the drier, so as to produce the solid byproduct.

7. A method for capturing carbon according to claim 6, wherein the method further comprises providing within the reactor a perforated screen for generating bubbles of the cooled exhaust gas within the solvent in the reactor so as to increase capture of carbon dioxide.

8. A method for capturing carbon dioxide according to claim 6 or claim 7, wherein the method further includes providing a solid dosing system coupled to the reactor, the dosing system being adapted to deliver a powdered reagent into the reactor, the reagent mixing with the solvent and operatively reacting with the carbon dioxide to form the by product.

9. A method for capturing carbon dioxide according to any one of claims 6 to 8, the method further including the step of providing a further heat exchanger configured to receive and recondense the water vapor from the drier for re-use.

10. A method for capturing carbon dioxide according to any one of claims 6 to 9, wherein the solvent is selected from an aqueous solution of CaO, MgO, NaOH or Na2CO3, and where the byproduct includes CaCO3, MgCO3, Na2CO3 or NaHCO3.

11. A carbon dioxide capture system for removing carbon dioxide from an exhaust gas stream, comprising: a gas pump configured to induce a flow of the exhaust gas into a heat exchanger, and thereby cool the exhaust gas;a reactor coupled to the heat exchanger to receive the cooled exhaust gas, the reactor including a volume of solvent and configured and dimensioned to operatively provide sufficient reaction time to facilitate transfer of a substantial part of the carbon dioxide in the exhaust gas into the solvent, and to allow for reaction of the carbon dioxide to form a byproduct rich fluid, and to release spent exhaust gas;a drier coupled to the reactor and configured to receive the byproduct rich fluid and evaporate water from the byproduct rich fluid to produce a solid byproduct and water vapor;wherein the reactor further includes a perforated screen for generating bubbles of the cooled exhaust gas within the solvent in the reactor so as to increase capture of carbon dioxide.12.. A carbon dioxide capture system according to claim 11, wherein a solid dosing system is coupled to the reactor, the dosing system being adapted to deliver a powdered reagent into the reactor, the reagent mixing with the solvent and operatively reacting with the carbon dioxide to form the by product.

13. A carbon dioxide capture system according to claim 11 or claim 12, wherein a further heat exchanger is configured to receive and recondense the water vapor from the drier for re-use.

14. A carbon dioxide capture system according to any one of claims 11 to 13, wherein the solvent is selected from an aqueous solution of CaO, MgO, NaOH or Na2CO3, and where the byproduct includes CaC03, MgCO3, Na2CO3 or NaHCO3.

15. A solid byproduct produced according to any one of the preceding method or system claims.

16. A cement or concrete that includes the solid byproduct produced according to the claim 15.

17. A method for capturing and sequestering carbon dioxide from an exhaust gas stream, including at least the steps of:Providing a gas pump configured to induce a flow of the exhaust gas into a heat exchanger, and thereby cool the exhaust gas;Providing a first reactor coupled to the heat exchanger to receive the cooled exhaust gas, the first reactor including a volume of solvent and configured and dimensioned to operatively provide sufficient reaction time to facilitate transfer of a substantial part of the carbon dioxide in the exhaust gas into the solvent, and to allow for reaction of the carbon dioxide to form a byproduct rich fluid, and to release spent exhaust gas;providing a drier coupled to the first reactor and configured to receive the byproduct rich fluid and evaporate water from the byproduct rich fluid to produce a solid byproduct and water vapor;the method including inducing a flow of exhaust gas through the heat exchanger, mixing the cooled exhaust gas with the solvent, capturing carbon dioxide in the byproduct in the solvent, drying the byproduct rich fluid to produce a solid byproduct, and forming a concrete product including the solid byproduct, so that the carbon dioxide is sequestered within the concrete product.

18. A method according to claim 17, wherein the solvent includes CaO, and the solid byproduct is substantially CaC03.

19. A method according to claim 18, wherein the concrete product is formed from a mixture including at least Portland cement, aggregate and the CaC03 byproduct.

20. A method according to claim 19, wherein the CaCO3 byproduct is between 5 and 30% by weight of the concrete product, wherein the heat transferred from the exhaust gas stream by the heat exchanger is used to operate the drier, so as to produce the solid byproduct.

21. A concrete product produced according to any one of claims 17 to 20.

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