A chemical looping combustion fuel composition, combustion system, and power generation system

Abstract

The application discloses a chemical looping combustion fuel composition, a combustion system and a power generation system. Fly ash zeolite-based composite nano oxygen carrier materials are prepared by taking fly ash generated in combustion as raw materials, and metal resources in the fly ash are recycled. Meanwhile, on the basis of retaining mature core equipment of a carbonaceous fuel boiler power generation system, only small-scale modification is carried out, that is, an oxygen carrier production module, a fuel pretreatment module and a local combustion atmosphere control module are introduced, and a flue gas path is adjusted, so that the carbonaceous boiler power generation system can be upgraded to a chemical looping combustion power generation system, a technical problem that CLC upgrading modification cannot be carried out on an existing boiler system is overcome, and the function of automatically capturing CO2-rich (>94%) gas is realized.

Description

[0001] This application claims the prior art of patent application filed on September 20, 2022, with the China National Intellectual Property Administration, patent application number 202211145968.4, entitled "A Chemical Chain Combustion Fuel Composition, Combustion System and Power Generation System". The entire contents of the prior application are incorporated herein by reference. Technical Field

[0002] This invention belongs to the field of power generation systems, specifically relating to a chemically looped combustion fuel composition, a combustion system, and a power generation system. Background Technology

[0003] Chemical Looping Combustion (CLC) is an advanced clean combustion technology with the ability to automatically separate CO2 gas. Significant progress and achievements have been made in various aspects, including oxygen carrier development, reaction kinetics, reactor design, system efficiency, and prototype testing of multiple reactors. The CLC system is also a clean combustion system for carbonaceous fuels. Regardless of whether the CLC system uses fossil fuels or organic renewable fuels, the flue gas recirculation can automatically provide CO2-enriched gas as a byproduct and completely suppress NO from hot air. x The CLC technology is a reliable energy technology that can tightly integrate CO2 capture with combustion, thus eliminating pollution. It is expected to become the mainstream technology for large-scale online carbon capture and real-time carbon sequestration in the future carbon fuel cogeneration industry, achieving net-zero carbon emissions for the industry.

[0004] To date, CLC systems have utilized various carbonaceous fuels (such as syngas, natural gas, biogas, coal, and biomass) and employed nickel, iron, copper, manganese, or calcium-based oxide carriers in solid-gas reactors of different types of dual-interconnected fluidized beds, including circulating fluidized beds, bubbling fluidized beds, and moving bed (MB) systems. However, the CLC system, based on the dual-interconnected fluidized bed gas-solid reactor process prototype, differs from the existing boiler equipment in most coal-fired or organic renewable fuel power generation units worldwide, making it impossible to upgrade existing boiler systems. Globally, nearly 40% of power generation plants use coal-fired or biomass-fired boiler systems. Repurchasing the core equipment of a "dual-interconnected fluidized bed boiler" would expose these power plants to substantial operational losses and the high risk of investing in a completely new system. How to upgrade CLC technology while preserving the core equipment of traditional boiler systems has become a pressing technical challenge for the thermal power industry.

[0005] Furthermore, fly ash generated by traditional boiler systems, if left uncontrolled or untreated, can cause industrial pollution, including metal contamination. The chemical substances accumulated during combustion can be harmful to organisms and humans. How to utilize fly ash and turn it from waste into a valuable resource is a technical problem that this field has been continuously working to solve. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention provides the following technical solution:

[0007] This invention provides the application of fly ash in the preparation of oxygen carriers or oxygen-fueled fuels, preferably chemical looping combustion (CLC) oxygen carriers. The fly ash is a fine ash particle emitted during fuel combustion, optionally containing or not containing unburned carbonaceous particles; fly ash including unburned carbonaceous particles is also known as pulverized fly ash or soot. In one embodiment, the fly ash is boiler combustion fly ash.

[0008] The present invention also provides an oxygen carrier, which is prepared from fly ash; preferably, the oxygen carrier is a chemical looping combustion oxygen carrier.

[0009] According to an embodiment of the present invention, the oxygen carrier contains a metal oxide, and the carrier is a microporous aluminosilicate crystal based on artificial zeolite or fly ash zeolite, wherein the metal element oxide contained in the fly ash is uniformly distributed in the crystal structure of the carrier.

[0010] According to one embodiment of the present invention, the oxygen carrier / support has a crystal structure of FAU zeolite, and preferably the iron oxide nanocrystal particles distributed therein have a structure of γ-Fe2O3, α-Fe2O3, or γ-Fe3O4.

[0011] According to an embodiment of the present invention, the oxygen carrier is a micro / nano material, that is, it has a micro / nano-scale crystal structure.

[0012] According to an embodiment of the present invention, the metal in the metal oxide is a metal element contained in fly ash, such as one or more of the elements K, Na, Al, Mg, Fe, Zn, Pb, Mn, Cu, and Cr.

[0013] According to an embodiment of the present invention, the mass ratio of the metal oxide to the oxygen carrier is 5 to 35 wt%, for example, 10 wt%, 15 wt%, 20 wt%, 25 wt%, or 30 wt%.

[0014] According to an embodiment of the present invention, the particle size of the oxygen carrier is 0.075 mm to 0.2 mm, for example, 100 μm, 120 μm, 150 μm, or 180 μm.

[0015] According to an embodiment of the present invention, the oxygen carrier is prepared from fly ash as raw material by a two-stage alkali conversion method of melt polymerization and hydrothermal reaction.

[0016] The present invention also provides a method for preparing the above-mentioned oxygen carrier, which is prepared by using fly ash as raw material through a two-stage alkali conversion method of melt polymerization and hydrothermal reaction.

[0017] According to an embodiment of the present invention, the preparation method includes the following steps: fly ash is melt-polymerized under alkaline conditions, the resulting polymer is ground, diluted, ultrasonically treated, and then activated by hydrothermal reaction to obtain the oxygen carrier.

[0018] According to an embodiment of the present invention, the alkaline conditions may be provided by a strong base, such as potassium hydroxide and / or sodium hydroxide.

[0019] According to an embodiment of the present invention, the conditions for the melting and polymerization include: a temperature of 400-650°C and a time of 2-8 hours; for example, a temperature of 450-550°C and a time of 4-6 hours.

[0020] According to an embodiment of the present invention, the polymer is ground to a thickness of 0.075 mm to 0.2 mm.

[0021] According to an embodiment of the present invention, the concentration of solid substances in the diluted mixture is 1-5 mol / L, for example 2.5 mol / L.

[0022] According to an embodiment of the present invention, the diluent used for dilution is water or a liquid medium recovered from a hydrothermal activation reaction.

[0023] According to an embodiment of the present invention, fly ash may or may not be added during dilution.

[0024] According to an embodiment of the present invention, the ultrasonic treatment time is 10-30 minutes, for example, 15 minutes.

[0025] According to an embodiment of the present invention, the conditions for the hydrothermal activation reaction include: a temperature of 70-100°C and a time of 2-8 hours; for example, a temperature of 80-90°C and a time of 4-8 hours.

[0026] According to an embodiment of the present invention, after the hydrothermal activation reaction is completed, the product is filtered, washed, and dried to obtain the oxygen carrier.

[0027] The present invention also provides an apparatus for producing the above-mentioned oxygen carrier, comprising a polymerization reactor, a grinding device, a dilution tank, an ultrasonic device, and a hydrothermal activation device connected in sequence.

[0028] According to an embodiment of the present invention, the polymerization reactor is provided with a fly ash inlet and an alkaline reagent inlet.

[0029] According to an embodiment of the present invention, the production apparatus further includes a filtration device, the liquid outlet of which is connected to a dilution tank via a pipeline for recycling and reuse of the filtered liquid medium.

[0030] The present invention also provides a combustion aid composition comprising the oxygen carrier.

[0031] Preferably, the combustion aid composition further includes metal oxide nanoparticles.

[0032] According to an embodiment of the present invention, the metal oxide nanoparticles account for 5 to 35 wt% of the combustion improver composition, for example, 10 wt%, 15 wt%, 20 wt%, 25 wt%, or 30 wt%.

[0033] According to embodiments of the present invention, the metal oxide nanoparticles include, but are not limited to, alkali transition metal oxide nanoparticles with oxidation catalytic activity, such as oxide nanoparticles of iron, chromium, manganese, cobalt, nickel, copper, aluminum, zirconium, tin, zinc, tungsten, molybdenum and vanadium; preferably, iron oxide nanoparticles, zinc oxide nanoparticles, and aluminum oxide nanoparticles; as an example, the metal oxide nanoparticles are ferric oxide nanoparticles, zinc oxide nanoparticles, and aluminum oxide nanoparticles.

[0034] According to an embodiment of the present invention, the shape of the ferric oxide nanoparticles can be ellipsoidal or other regular or irregular shapes.

[0035] According to an embodiment of the present invention, the particle size of the metal oxide nanoparticles is 0.1-100 nm, for example 1-50 nm, with exemplary values ​​of 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, and 50 nm.

[0036] In one embodiment, the metal oxide nanoparticles are ferric oxide nanoparticles with a particle size of 3-5 nm, preferably ellipsoidal in shape.

[0037] According to an embodiment of the present invention, the combustion aid composition further includes one or more metal complexes or non-metal complexes, mainly used to modify or promote the catalytic function of active metal elements in metal oxide nanoparticles and / or oxygen carriers, such as being able to cooperate with or compensate for the function of these metal elements.

[0038] According to an embodiment of the present invention, the metal element of the metal complex may be selected from rare earth metal elements and / or half-metal elements; for example, the rare earth metal element is lanthanum (La) or cerium (Ce), preferably cerium; for example, the half-metal element is silicon (Si).

[0039] According to embodiments of the present invention, the metal complex may also be selected from metal compounds such as ruthenium, nickel, palladium, silver, platinum, nickel, cobalt, vanadium, aluminum, chromium, copper, zinc, molybdenum, tin, manganese, gold, rhodium, zirconium, tungsten, rhenium, osmium, iridium, and titanium, preferably compounds of aluminum and zinc, and more preferably aluminum oxide and zinc oxide.

[0040] In one embodiment, the rare earth metal element is derived from its salt or oxide, and the half-metal element is derived from its oxide (e.g., silicon dioxide).

[0041] In one embodiment, the metal compound is a corresponding metal salt or oxide.

[0042] According to an embodiment of the present invention, the metal complex is a nanoscale metal oxide, such as nano-cerium oxide, nano-aluminum oxide, and / or nano-zinc oxide.

[0043] According to an embodiment of the present invention, the combustion aid composition further includes a liquid regulator, for example, the liquid regulator is selected from primary regulators, secondary regulators or liquid media.

[0044] According to an embodiment of the present invention, the mass ratio of the metal oxide nanoparticles, metal complexes, or non-metal complexes to the liquid regulator is 0.5 to 15 wt%, for example, 1 wt%, 3 wt%, 5 wt%, 7 wt%, 10 wt%, or 12 wt%.

[0045] In one embodiment, the metal oxide nanoparticles or metal complexes enter the combustion system together with the liquid conditioner, or form a dispersion with the liquid conditioner and enter the combustion system.

[0046] For example, the primary regulator is selected from small molecule organic solvents and / or polymers (which may be selected from oligomers). The primary dispersant contains one or more functional groups to disperse metal oxide nanoparticles or catalyst complexes through mechanisms such as ionic bonds, covalent bonds, van der Waals interactions / bonding, lone pair electron bonds, or hydrogen bonds, in any one or more of the above mechanisms. For example, the functional group includes a carbon atom bonded to at least one electron-rich atom, which is more electronegative than a carbon atom and can donate one or more electrons to form a bond or attraction with the metal element. Preferably, the primary regulator includes a charge or one or more lone electrons, which can be used to composite the metal catalyst element, or can form other types of bonds, such as hydrogen bonds. These functional groups enable the primary regulator to have a strong binding effect with the metal element. As an example, the functional group may be selected from substituted or unsubstituted hydroxyl, carboxyl, carbonyl, amino, acyl, amide, nitrile, nitrogen with free lone pair electrons, sulfonic acid, etc.

[0047] The small molecule organic solvent is selected from monofunctional, bifunctional, multifunctional organic solvents, or other small molecule organic solvents. For example, a monofunctional organic solvent is selected from one or more of methanol, ethanol, n-propanol, isopropanol, formic acid, acetic acid, acetonitrile, acetone, tetrahydroacetonitrile, dichloromethane, dimethylbromoamide, dimethyl sulfoxide, etc. For example, a bifunctional organic solvent is selected from one or more of oxalic acid, malic acid, malonic acid, malic acid, succinic acid, ethylene glycol, propylene glycol, 1,3-propanediol, glycolic acid, lactic acid, etc. For example, a multifunctional organic solvent is selected from one or more of glucose, polysalicylic acid, citric acid, pectin, cellulose, etc. For example, other small molecule organic solvents may be selected from one or more of ethylamine, mercaptoethanol, 2-mercaptoacetyl, amino acids (such as glycine), sulfonic acid, sulfobenzyl alcohol, fluorobenzoic acid, sulfothiol, sulfobenzylamine, triiodoethanol, sulfonyl halides, acyl halides, etc.

[0048] According to embodiments of the present invention, the primary regulator may further include inorganic components (e.g., silicon-based).

[0049] According to embodiments of the present invention, the metal oxide nanoparticles, metal complexes and / or non-metal complexes can form complexes (preferably nanoscale complexes) with the small molecule organic solvent, preferably forming stable suspensions or colloids.

[0050] According to embodiments of the present invention, the polymer includes, but is not limited to, one or more of the following: polyacrylate, polyethylene benzoate, polyvinyl sulfate, vinyl sulfonate (e.g., sulfonated styrene), polybisphenol carbonate, polybenzimidazole, polyvinyl alcohol, polyethylene glycol, polyacrylol (e.g., polypropylene glycol), polybenzoxazole imidazole, polypyridine, sulfonated polyethylene terephthalate, sulfonated styrene, etc.

[0051] According to an embodiment of the present invention, in a dispersion system formed of a primary regulator and a solid (metal oxide nanoparticles or catalyst complex), the size of the solid is less than 0.5 micrometers, for example less than 0.1 micrometers.

[0052] According to an embodiment of the present invention, the molar ratio of the primary regulator to the metal element is in the range of approximately 0.001:1 to 50:1, preferably in the range of 0.005:1 to 10:1, and most preferably in the range of 0.01:1 to 1:1.

[0053] According to embodiments of the present invention, the liquid conditioner may further contain secondary conditioners, such as landfill leachate, HTC process media water, or other biomass energy liquids, which can all serve as inexpensive organic solvents. Landfill leachate contains metal salts. This not only reduces solvent costs but also enables the removal of permanent metal and organic pollutants from landfills. The secondary conditioner is primarily used to dilute and disperse the primary system to obtain a large-volume, homogeneous secondary system.

[0054] According to an embodiment of the present invention, the volume ratio of the secondary regulator to the primary regulator is (10-1000):1, for example 10:1, 100:1, or 1000:1, preferably 100:1.

[0055] According to an embodiment of the present invention, in the secondary system, the size of the metal oxide nanoparticles and / or metal complexes is less than 300 nm, preferably less than 200 nm, more preferably less than 100 nm, and even more preferably less than 30 nm, 10 nm, or 4 nm.

[0056] According to an embodiment of the present invention, the liquid medium may be selected from carbon hydrogen. The carbon hydrogen may be selected from the bio-combustion-supporting materials disclosed in the specific embodiments of Chinese Patent Specification No. 201510271762.X, Authorization Announcement No. CN104877714B.

[0057] According to embodiments of the present invention, the combustion aid composition may further comprise additives. For example, the additives may be one or more inorganic acids, inorganic bases, etc. For instance, the inorganic acid may be selected from hydrochloric acid, nitric acid, sulfuric acid, and / or phosphoric acid, and the inorganic base may be selected from sodium hydroxide, potassium hydroxide, calcium hydroxide, and / or ammonium hydroxide, etc. The additives are used in small amounts.

[0058] As an example, glycolic acid, as one of the dispersants, helps to prevent or at least delay the aggregation of nanoparticles and the deactivation of the catalyst, which can improve combustion efficiency.

[0059] The aforementioned liquid conditioners and / or additives are used to adjust the combustion atmosphere of the CLC.

[0060] The present invention also provides an oxygen fuel comprising the above-mentioned oxygen carrier.

[0061] The present invention also provides a fuel composition comprising a fuel matrix and the above-described oxygen fuel.

[0062] According to an embodiment of the present invention, the fuel matrix can be a fossil fuel or a recycled carbon material, such as water coke or high-sodium coal fuel.

[0063] In one embodiment, the water coke is prepared by using biomass solid waste as raw material through the HTC hydrothermal carbonization method, and the system used adopts the co-liquid reaction system provided in Chinese patent application 202210190471.8.

[0064] In one embodiment, the fuel composition further includes the above-described combustion aid composition.

[0065] According to an embodiment of the present invention, the oxygen carrier accounts for 5 to 15 wt% of the oxygen fuel, for example, 7 wt%, 10 wt%, or 12 wt%.

[0066] The present invention also provides a clean combustion method, comprising adding the above-mentioned oxygen carrier, oxygen fuel, or combustion aid composition during the combustion of a fuel matrix; or, wherein the fuel matrix is ​​combusted in a combustion system as shown below. Preferably, in the method, cleaned flue gas is used as the gaseous medium for combustion reaction and heat conduction.

[0067] The present invention also provides a combustion system, comprising: a combustion furnace and an oxygen carrier production module, wherein fly ash discharged from the combustion furnace enters the oxygen carrier production module through a pipeline. The oxygen carrier production module is the aforementioned oxygen carrier production device. Preferably, the combustion system is a nitrogen-free atmosphere system.

[0068] According to an embodiment of the present invention, the combustion system further includes a fuel pretreatment module, which is connected to the material inlet of the combustion furnace.

[0069] In one embodiment, the fuel pretreatment module is a co-liquid reaction system provided in Chinese patent application 202210190471.8.

[0070] According to an embodiment of the present invention, the oxygen carrier outlet of the oxygen carrier production module is connected to the fuel pretreatment module. In the fuel pretreatment module, the uniform mixing of water-coke dispersion-supported nanoparticles is simultaneously completed.

[0071] According to an embodiment of the present invention, the fuel pretreatment module is connected to the biomass waste storage module.

[0072] According to an embodiment of the present invention, the combustion system further includes a local combustion atmosphere control module disposed below the combustion furnace and connected to the combustion furnace.

[0073] According to an embodiment of the present invention, the local combustion atmosphere control module provides a combustion complex suspension to the combustion furnace. The combustion complex suspension is a mixture of metal oxide nanoparticles, metal complexes and / or non-metal complexes and liquid regulators. For different fuels, different complex elements are added to adjust the local combustion atmosphere through injection.

[0074] According to an embodiment of the present invention, the local combustion atmosphere control module further includes a small air separation unit (ASU) or liquid oxygen backup, which is installed on the furnace injection pipe to achieve precise control of the injection of the local combustion complex suspension in the furnace.

[0075] According to an embodiment of the present invention, a chemical looping combustion reaction occurs in the combustion furnace. The oxygen-loaded oxygen in the oxygen carrier reacts with the fuel to produce CO2 and water. After the oxygen carrier-containing combustion reaction, the "oxygen holes" in the metal element lattice are restored to oxygen load through air reduction and chemical activation during the lattice material production process, and then participate in fuel combustion in a cycle. Therefore, this combustion system does not require a separate air separation unit for oxygen supply.

[0076] Preferably, the oxygen or liquid oxygen produced by the small air separation unit is used as a backup to adjust the oxygen content of the injected clean flue gas. The injected clean flue gas is CO2-enriched flue gas after chemical loop combustion, originating from the flue gas that has undergone cleaning treatment and been diverted after combustion in the combustion furnace. For boilers using high-sodium coal fuel, localized injection of suspension can also prevent coking caused by alkali metal evaporation.

[0077] According to an embodiment of the present invention, the combustion system includes a flue gas treatment module connected to the combustion furnace, comprising a waste heat furnace, a desulfurization device, and / or a dust collector. In one embodiment, the flue gas treatment module includes a waste heat furnace, a desulfurization device, and a dust collector connected in sequence, wherein the flue gas discharged from the combustion furnace is sequentially treated through cleaning processes such as waste heat recovery, desulfurization, and dust removal.

[0078] According to an embodiment of the present invention, the combustion system further includes a circulating loop for clean flue gas to enter the furnace.

[0079] According to an embodiment of the present invention, the combustion system further includes an air preheater.

[0080] In one embodiment, the combustion system includes a cleaned flue gas path with two branches. The first branch passes through an air preheater to become a heat-conducting medium that enriches CO2 in the furnace and a nitrogen-free atmosphere. The second branch produces CO2-enriched gas for industrial use as carbon sequestration or CO2 gas feedstock.

[0081] According to an embodiment of the present invention, the oxygen carrier production module includes an inlet for chemical raw materials such as fly ash and an outlet for finished zeolite-based oxygen carrier materials. The thermal energy required for the production device comes from different heating ports of the cascade flue gas heat source output from the combustion furnace.

[0082] According to an embodiment of the present invention, the fuel pretreatment module includes a heating flue gas inlet / outlet port from a heat source of cascaded flue gas output from a combustion furnace.

[0083] According to an embodiment of the present invention, the combustion furnace further includes a combustion furnace flue gas circuit, which is connected in parallel with the backup oxygen supply device pipeline injected into the furnace. Preferably, the flue gas passing through the air preheater is used as the injection gas medium for transporting the catalytic complex suspension, thereby precisely controlling and regulating the local combustion atmosphere.

[0084] This invention provides an integrated system comprising the aforementioned combustion system and power generation system. The combustion system generates H2O, CO2, and hot gas flow, which are then used to generate electricity through heat exchange. The power generation system is a known type of power generation system in the art.

[0085] Beneficial effects

[0086] This invention is the first to prepare fly ash zeolite-based composite nano-oxygen carrier material using fly ash produced by combustion as raw material, recycling the metal resources in the fly ash material; at the same time, based on retaining the core equipment of the mature carbon-fueled boiler power generation system, only minor modifications are made: introducing an oxygen carrier production module, a fuel pretreatment module, and a local combustion atmosphere control module, and adjusting the flue gas path, the carbon-fueled boiler power generation system can be upgraded to a chemical loop combustion power generation system, completely overcoming the technical difficulty that the CLC system based on the dual-interconnected fluidized bed gas-solid reactor process prototype is different from the current boiler equipment of most coal-fired power generation units worldwide, making it impossible to upgrade and modify the existing boiler system.

[0087] The combustion system provided by this invention generates H2O, CO2, and hot gas flow, which are then used to generate electricity through heat exchange. This enables the recycling of fly ash metal materials and achieves the function of automatically capturing and enriching (>94%) CO2 gas after combustion. Attached Figure Description

[0088] Figure 1 Process flow diagram for oxygen loading;

[0089] Figure 2 This is a flowchart of the preparation process for the oxygen carrier.

[0090] Figure 1-2 The fly ash zeolite-based nanocomposite material in the process serves as an oxygen carrier.

[0091] Figure 3 Flowchart of the preparation process for water-soluble coke;

[0092] Figure 4 This is a schematic diagram of the power generation system. Detailed Implementation

[0093] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0094] Unless otherwise stated, the raw materials and reagents used in the following implementation schemes are commercially available products or can be prepared by known methods.

[0095] [Oxygen carrier and its preparation process]

[0096] The preparation of the oxygen carrier includes the following steps (e.g. Figure 2 As shown): Fly ash was melt-polymerized in the presence of sodium hydroxide at a temperature of 550℃ for 1 hour. The resulting polymer was ground to 0.075 mm to 0.2 mm and diluted with water or the liquid medium recovered from the hydrothermal activation reaction to a solid concentration of 2.5 mol / L. The polymer was then ultrasonically treated for 15 minutes and subjected to hydrothermal activation at a temperature of 90℃ for 4 hours. After the hydrothermal activation reaction was completed, the product was filtered, washed, and dried to obtain an oxygen carrier.

[0097] The prepared oxygen carrier has a particle size of 0.075 mm to 0.2 mm and contains metal oxides. The carrier is a microporous aluminosilicate crystal based on artificial zeolite or fly ash zeolite. The oxides of metal elements contained in fly ash are uniformly distributed in the crystal structure of the carrier. The mass ratio of metal oxides to oxygen carrier is 5 to 35 wt%, for example, 10 wt%, 15 wt%, 20 wt%, 25 wt%, and 30 wt%.

[0098] In one embodiment, the oxygen carrier / support has a crystal structure of FAU zeolite, preferably wherein the distributed iron oxide nanocrystal particles have a structure of γ-Fe2O3, α-Fe2O3, or γ-Fe3O4.

[0099] The oxygen carrier can be prepared using the following production equipment, which includes a polymerization reactor, a grinding device, a dilution tank, an ultrasonic device, and a hydrothermal activation device connected in sequence.

[0100] The polymerization reactor is equipped with a fly ash inlet and an alkaline reagent inlet.

[0101] The production unit also includes a filtration device, whose liquid outlet is connected to a dilution tank via a pipeline, allowing for the recycling and reuse of the filtered liquid medium.

[0102] Combustion aid composition—complex suspension

[0103] The combustion aid composition comprises metal complex nanoparticles, wherein the metal oxide nanoparticles account for 5–35 wt% of the combustion aid composition, for example, 10 wt%, 15 wt%, 20 wt%, 25 wt%, or 30 wt%. The metal oxide nanoparticles include, but are not limited to, alkali transition metal oxide nanoparticles with oxidative catalytic activity, such as oxide nanoparticles of iron, chromium, manganese, cobalt, nickel, copper, aluminum, zirconium, tin, zinc, tungsten, molybdenum, and vanadium; preferably, iron oxide nanoparticles, zinc oxide nanoparticles, or aluminum oxide nanoparticles; as an example, the metal oxide nanoparticles are ferric oxide nanoparticles, zinc oxide nanoparticles, or aluminum oxide nanoparticles.

[0104] In one embodiment, the ferric oxide nanoparticles may be ellipsoidal or other regular or irregular shapes.

[0105] In one embodiment, the particle size of the metal oxide nanoparticles is 0.1-100nm, for example 1-50nm, with exemplary values ​​of 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, and 50nm.

[0106] In one embodiment, the metal oxide nanoparticles are ferric oxide nanoparticles with a particle size of 3-5 nm, preferably ellipsoidal in shape.

[0107] In one embodiment, the combustion aid composition further includes one or more metal complexes, primarily used to modify or enhance the catalytic function of active metal elements in metal oxide nanoparticles and / or oxygen carriers, such as being able to coordinate with or compensate for the function of these metal elements.

[0108] In one embodiment, the metal element of the metal complex may be selected from rare earth metal elements and / or half-metal elements; for example, the rare earth metal element is lanthanum (La) or cerium (Ce), preferably cerium; for example, the half-metal element is silicon (Si).

[0109] In one embodiment, the metal complex may also be selected from metal compounds such as ruthenium, nickel, palladium, silver, platinum, nickel, cobalt, vanadium, aluminum, chromium, copper, zinc, molybdenum, tin, manganese, gold, rhodium, zirconium, tungsten, rhenium, osmium, iridium, and titanium, preferably compounds of aluminum and zinc, and more preferably aluminum oxide and zinc oxide.

[0110] In one embodiment, the rare earth metal element is derived from its salt or oxide, and the half-metal element is derived from its oxide (e.g., silicon dioxide).

[0111] In one embodiment, the metal compound is a corresponding metal salt or oxide.

[0112] In one embodiment, the metal complex is a nanoscale metal oxide, such as nano-cerium oxide, nano-aluminum oxide, and / or nano-zinc oxide.

[0113] In one embodiment, the combustion aid composition further includes a liquid regulator, such as a primary regulator, a secondary regulator, or a liquid medium.

[0114] In one embodiment, the mass ratio of the metal oxide nanoparticles and / or non-metallic complex to the regulator of the liquid suspension is 0.5 to 15 wt%, for example, 1 wt%, 3 wt%, 5 wt%, 7 wt%, 10 wt%, or 12 wt%.

[0115] In one embodiment, the metal oxide nanoparticles and / or the non-metal complex suspension, along with the regulator, enter the combustion system together, or the complex dispersion formed with the regulator enters the combustion system.

[0116] For example, the primary regulator is selected from small molecule organic solvents and / or polymers (which may be selected from oligomers). The primary dispersant contains one or more functional groups to disperse metal oxide nanoparticles or catalyst complexes through mechanisms such as ionic bonds, covalent bonds, van der Waals interactions / bonding, lone pair electron bonds, or hydrogen bonds, in any one or more of the above mechanisms. For example, the functional group includes a carbon atom bonded to at least one electron-rich atom, which is more electronegative than a carbon atom and can donate one or more electrons to form a bond or attraction with the metal element. Preferably, the primary regulator includes a charge or one or more lone electrons, which can be used to composite the metal catalyst element, or can form other types of bonds, such as hydrogen bonds. These functional groups enable the primary regulator to have a strong binding effect with the metal element. As an example, the functional group may be selected from substituted or unsubstituted hydroxyl, carboxyl, carbonyl, amino, acyl, amide, nitrile, nitrogen with free lone pair electrons, sulfonic acid, etc.

[0117] The small molecule organic solvent is selected from monofunctional, bifunctional, multifunctional organic solvents, or other small molecule organic solvents. For example, a monofunctional organic solvent is selected from one or more of methanol, ethanol, n-propanol, isopropanol, formic acid, acetic acid, acetonitrile, acetone, tetrahydroacetonitrile, dichloromethane, dimethylbromoamide, dimethyl sulfoxide, etc. For example, a bifunctional organic solvent is selected from one or more of oxalic acid, malic acid, malonic acid, malic acid, succinic acid, ethylene glycol, propylene glycol, 1,3-propanediol, glycolic acid, lactic acid, etc. For example, a multifunctional organic solvent is selected from one or more of glucose, polysalicylic acid, citric acid, pectin, cellulose, etc. For example, other small molecule organic solvents may be selected from one or more of ethylamine, mercaptoethanol, 2-mercaptoacetyl, amino acids (such as glycine), sulfonic acid, sulfobenzyl alcohol, fluorobenzoic acid, sulfothiol, sulfobenzylamine, triiodoethanol, sulfonyl halides, acyl halides, etc.

[0118] In one embodiment, the primary regulator may further include an inorganic component (e.g., silicon-based).

[0119] In one embodiment, the metal oxide nanoparticles and / or other non-metallic complexes can form complexes (preferably nanoscale complexes) with the small molecule organic solvent, preferably forming stable suspensions or colloids.

[0120] In one embodiment, the polymer includes, but is not limited to, one or more of the following: polyacrylate, polyethylene benzoate, polyvinyl sulfate, vinyl sulfonate (e.g., sulfonated styrene), polybisphenol carbonate, polybenzimidazole, polyvinyl alcohol, polyethylene glycol, polyacrylol (e.g., polypropylene glycol), polybenzoxazole imidazole, polypyridine, sulfonated polyethylene terephthalate, and sulfonated styrene.

[0121] In one embodiment, in a liquid dispersion system formed by a primary regulator and a solid (metal oxide nanoparticles as a catalytic complex), the size of the solid is less than 0.5 micrometers, for example less than 0.1 micrometers.

[0122] In one embodiment, the molar ratio of the primary regulator to the metal element is in the range of approximately 0.001:1 to 50:1, preferably in the range of 0.005:1 to 10:1, and most preferably in the range of 0.01:1 to 1:1.

[0123] In one embodiment, the liquid conditioner may also contain a secondary conditioner, such as landfill leachate, HTC process medium water, or other biomass energy liquids, which can all serve as inexpensive organic solvents. Landfill leachate contains metal salts. This not only reduces solvent costs but also enables the removal of permanent metal and organic contaminants from landfills. The secondary conditioner is primarily used to dilute and disperse the primary system to obtain a large-volume, homogeneous secondary system.

[0124] In one embodiment, the volume ratio of the secondary regulator to the primary regulator is (10-1000):1, for example, 10:1, 100:1, or 1000:1, preferably 100:1.

[0125] In one embodiment, in the secondary system, the size of the metal oxide nanoparticles and / or metal complexes is less than 300 nm, preferably less than 200 nm, more preferably less than 100 nm, and even more preferably less than 30 nm, 10 nm, or 4 nm.

[0126] In one embodiment, the liquid medium may be selected from carbon hydrogen. The carbon hydrogen may be selected from the bio-combustion-supporting materials disclosed in the specific embodiments of Chinese Patent Specification No. 201510271762.X, Authorization Announcement No. CN104877714B.

[0127] In one embodiment, the combustion aid composition may further comprise an additive. For example, the additive may be one or more inorganic acids, inorganic bases, etc. For instance, the inorganic acid may be selected from hydrochloric acid, nitric acid, sulfuric acid, and / or phosphoric acid, and the inorganic base may be selected from sodium hydroxide, potassium hydroxide, calcium hydroxide, and / or ammonium hydroxide, etc. The additive is used in small amounts.

[0128] As an example, glycolic acid, as one of the dispersants, helps to prevent or at least delay the aggregation of nanoparticles and the deactivation of the catalyst, which can improve combustion efficiency.

[0129] The aforementioned liquid conditioners and / or additives are used to adjust the combustion atmosphere of the CLC.

[0130] [Oxygen fuel]

[0131] An oxygen fuel containing the above-mentioned oxygen carrier, wherein the mass ratio of the oxygen carrier to the oxygen fuel is 5 to 15 wt%, for example 7 wt%, 10 wt%, or 12 wt%.

[0132] [Fuel Composition]

[0133] The fuel composition includes a combination of various fuel matrices and the aforementioned oxygen fuels, wherein the fuel matrices are fossil fuels or recycled carbon materials, such as water coke or high-sodium coal fuel.

[0134] Water coke is prepared from biomass solid waste through the HTC hydrothermal carbonization method. The system used adopts the co-liquid reaction system provided in Chinese patent application 202210190471.8.

[0135] In one embodiment, the fuel composition further includes the above-described combustion aid composition.

[0136] [Clean Combustion Methods]

[0137] A clean combustion method includes adding the above-mentioned oxygen carrier, oxygen fuel, or combustion aid composition during the combustion of a fuel matrix; or, the fuel matrix is ​​combusted in a combustion system as shown below.

[0138] [Combustion system, and integrated system of combustion system and power generation system]

[0139] like Figure 4 The integrated system shown consists of a combustion system and a power generation system. The H2O, CO2, and hot gas generated by the combustion system are output to generate electricity through heat exchange.

[0140] The combustion system includes a combustion furnace and an oxygen carrier production module. The fly ash discharged from the combustion furnace enters the oxygen carrier production module through pipelines. The oxygen carrier production module is the aforementioned oxygen carrier production device, which includes an inlet for chemical raw materials such as fly ash and an outlet for the zeolite-based oxygen carrier finished material. The heat energy required for the production device comes from different heating ports of the cascade flue gas heat source output from the combustion furnace.

[0141] The combustion system also includes a fuel pretreatment module, which is connected to the material inlet of the combustion furnace. The fuel pretreatment module is a co-liquid reaction system as provided in Chinese patent application 202210190471.8, such as... Figure 3 As shown.

[0142] The oxygen carrier outlet of the oxygen carrier production module is connected to the fuel pretreatment module. In the fuel pretreatment module, the uniform mixing of water-coke dispersion-supported nanoparticles is completed simultaneously.

[0143] The fuel pretreatment module is connected to the biomass waste storage module.

[0144] The combustion system also includes a localized combustion atmosphere control module, located below and connected to the combustion furnace. This module injects a combustion complex suspension into a designated area of ​​the combustion furnace. The combustion complex suspension is a mixture of metal oxide nanoparticles and / or non-metallic complexes with a liquid conditioner. Different complexing elements are added for different fuels, and the localized combustion atmosphere is adjusted through injection. The localized combustion atmosphere control module also includes a small air separation unit (ASU) or liquid oxygen backup, installed on the furnace inlet injection duct, for precise control of the injection of the localized combustion complex suspension within the furnace.

[0145] A chemical chain combustion reaction occurs inside the combustion furnace. The oxygen-loaded agent reacts with the fuel to produce CO2 and water. After the oxygen-loaded agent undergoes the combustion reaction, the "oxygen holes" in the metal element lattice are restored through air reduction and chemical activation during the lattice material production process, and then participate in fuel combustion in a cycle (e.g., Figure 1 (As shown). Therefore, this combustion system does not require a separate air separation unit for oxygen supply.

[0146] The oxygen or liquid oxygen produced by the small air separation unit is used as a backup to adjust the oxygen content of the injected clean flue gas. The injected clean flue gas is CO2-enriched flue gas after chemical loop combustion, originating from the flue gas that has undergone cleaning treatment and been diverted after combustion in the combustion furnace. For boilers using high-sodium coal fuel, localized injection of suspension can also prevent coking caused by alkali metal evaporation.

[0147] The combustion system includes a flue gas treatment module connected to the combustion furnace, comprising a waste heat furnace, a desulfurization device, and / or a dust collector. In one embodiment, the flue gas treatment module includes a waste heat furnace, a desulfurization device, and a dust collector connected in sequence, wherein the flue gas discharged from the combustion furnace is treated sequentially through cleaning processes such as waste heat recovery, desulfurization, and dust removal.

[0148] The combustion system also includes an air preheater. The combustion system includes a cleaned flue gas path with two branches. The first branch passes through the air preheater to become a heat-conducting gas medium that enriches CO2 in the furnace. The second branch produces CO2-enriched gas, which is output for industrial use as carbon sequestration or CO2 gas feedstock.

[0149] The fuel pretreatment module includes inlet and outlet ports for heated flue gas from the combustion furnace's output cascade flue gas heat source. The combustion furnace also includes a combustion furnace flue gas circuit, which is connected in parallel with the backup oxygen supply device pipeline for injection into the furnace. Preferably, flue gas passing through the air preheater is used as the injection gas medium for transporting the catalytic complex suspension, enabling precise control and regulation of the local combustion atmosphere.

[0150] This invention is the first to prepare fly ash zeolite-based composite nano-oxygen carrier materials using fly ash generated during combustion as raw material, thus recycling the metal resources in the fly ash. Simultaneously, while retaining the core equipment of a mature carbon-fueled boiler power generation system, only minor modifications are made: introducing an oxygen carrier production module, a fuel pretreatment module, and a local combustion atmosphere control module, and adjusting the flue gas path. This upgrades the carbon-fueled boiler power generation system to a chemical loop combustion power generation system, completely overcoming the technical challenge of upgrading existing boiler systems due to the difference between the CLC system based on the dual-interconnected fluidized bed gas-solid reactor process and the existing boiler equipment of most coal-fired power generation units worldwide. The combustion system provided by this invention generates H2O, CO2, and hot gas flow, which outputs power generation heat energy through heat exchange, realizing the recycling of fly ash metal materials and achieving the function of automatically capturing and enriching (>94%) CO2 gas after combustion.

[0151] A comparison of the catalytic combustion-enhancing effects of FAU zeolite, oxygen-carrying water-carbon (water coke), and metal oxides as solid oxygen carrier media.

[0152] Replacing the oxygen carrier medium in traditional chemical looping combustion with a disposable oxygen carrier medium requires constructing a carrier medium in the continuous combustion system that has been recovered from the combustion ash and reduced to oxygen for reloading. Therefore:

[0153] (1) The present invention uses fly ash to prepare zeolite-based industrial processes to load solid metal oxygen, thereby realizing the loading of solid oxygen in the zeolite cage-frame pore nanostructure.

[0154] (2) This invention utilizes the fuel characteristics of biomass combustion power generation industrial devices and uses the HTC process to perform hydrothermal carbonization pretreatment on biomass fuel. The process designed in this invention can recover metal oxides after oxygen supply and reduction combustion, and can also simultaneously prepare biomass into oxygen fuel (the method for preparing oxygen-carrying water carbon is not disclosed).

[0155] Traditional oxygen carrier media in chemical loop combustion circuits need to be reused, thus imposing stringent requirements on the physical properties of the carrier media materials. The obstacle to their application lies in the loss of activity after multiple redox reactions. Disposable oxygen carrier media do not suffer from this deactivation efficiency problem. However, since the technical solution of this invention requires the continuous and large-scale use of disposable oxygen carrier media, using fly ash to prepare FAU zeolite-loaded metal oxides as a disposable oxygen carrier medium can improve the activity of the metal oxides and increase the efficiency of oxide reduction oxygen supply combustion. A better solution is to utilize the HTC process to recover the metal oxides after oxygen reduction combustion during biomass fuel pretreatment while simultaneously preparing oxygen fuel (oxygen-loaded water coke).

[0156] The nano-metal oxides include, but are limited to, alkali transition metal oxide nanoparticles with oxidation catalytic activity, such as oxide nanoparticles of iron, chromium, manganese, cobalt, nickel, copper, aluminum, zirconium, tin, zinc, tungsten, molybdenum, and vanadium; preferably, iron oxide nanoparticles, zinc oxide nanoparticles, and aluminum oxide nanoparticles; as examples, the nano-metal oxide particles are ferric oxide nanoparticles, zinc oxide nanoparticles, and aluminum oxide nanoparticles. In one embodiment, the ferric oxide nanoparticles may be ellipsoidal or other regular or irregular shapes.

[0157] TG-MS mass spectrometry can sensitively detect the intensity of CO2 gas produced by combustion, thus accurately reflecting the differences in catalytic combustion effects.

[0158] Samples of FAU zeolite composition loaded with nano-metal oxides, samples of oxygen-carrying water-carbon composition loaded with nano-metal oxides, and samples of nano-metal oxide particle composition were mixed evenly with peat fuel (the ratio of nano-metal oxide loaded medium composition sample to peat was 2:5), and then placed in a thermogravimetric analyzer with a heating rate of 20℃ / min, held at 900℃ for 1h, and an argon flow rate of 60ml / min.

[0159] Relative integrated area of ​​CO2 mass spectrum signal produced per gram of peat combustion

[0160]

[0161] In the table above, the nano-metal oxide composition is: 38% nano Fe2O3, 19% nano Al2O3, 19% nano ZnO, and 25% nano CeO2.

[0162] The results show that the solid oxygen carrier using FAU zeolite as a support exhibits better combustion performance than simple nano-metal oxides without a support. This is related to the cage-like porous nanostructure of the zeolite itself, which uniformly disperses the nano-metal oxides, promoting oxygen release and catalytic combustion. Therefore, zeolite materials loaded with nano-metal oxides and oxygen-carrying water coke have significantly higher oxygen supply and catalytic combustion effects than combinations of metal oxides.

[0163] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A combustion improver composition characterized by comprising, The composition includes an oxygen carrier, metal oxide nanoparticles, and cerium nanoparticles. The oxygen carrier contains metal oxides, and the carrier of the oxygen carrier is fly ash zeolite-based microporous aluminosilicate crystals, in which the metal oxides contained in the fly ash are uniformly distributed in the crystal structure of the carrier. The oxygen carrier has a crystal structure of FAU zeolite, wherein the distributed iron oxide nanocrystal particles have a structure of γ-Fe2O3, α-Fe2O3 and / or Fe3O4; the particle size of the oxygen carrier is 0.075 mm to 0.2 mm. The oxygen carrier is prepared from fly ash as raw material through a two-stage alkaline conversion method of melting-hydrothermal process, specifically including the following steps: the fly ash is melted under alkaline conditions, the resulting mixture is ground, diluted, ultrasonically treated, and then activated by a hydrothermal reaction to obtain the oxygen carrier; The metal oxide nanoparticles account for 5-35 wt% of the combustion aid composition; The metal oxide nanoparticles are selected from oxide nanoparticles of iron, chromium, manganese, cobalt, nickel, copper, aluminum, zirconium, tin, zinc, tungsten, molybdenum and / or vanadium.

2. The combustion improver composition of claim 1, wherein The metal oxide nanoparticles are selected from iron oxide nanoparticles, zinc oxide nanoparticles and / or aluminum oxide nanoparticles.

3. The combustion improver composition of claim 1, wherein The metal oxide nanoparticles are selected from ferric oxide nanoparticles, zinc oxide nanoparticles, and / or aluminum oxide nanoparticles.

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