Preparation method and application of La@Fe2O3 nanoparticle combustion improver and its dispersion

Abstract

The present invention discloses a La@Fe2O3 nanoparticle combustion improver, a dispersion of the combustion improver, and a preparation method thereof. The La@Fe2O3 nanoparticle combustion improver is prepared by reacting amino acid-activated Fe2O3 nanoparticles with a lanthanum ligand solution. The La@Fe2O3 nanoparticle combustion improver helps promote combustion of gas, thereby increasing its combustion efficiency. The La@Fe2O3 nanoparticle combustion improver prepared using the present method can be stably dispersed in methoxypolyvinyl alcohol glycerol ether to form a stable La@Fe2O3 nanoparticle combustion improver dispersion. This dispersion can be mixed with gas through a dilution spray atomization method without disrupting the original natural gas boiler combustion system, thereby improving the combustion efficiency of the gas.

Description

Technical Field

[0001] The invention relates to a La@Fe2O3 nanoparticle combustion improver and a preparation method and application of a dispersion thereof, belonging to the technical field of environmental protection. Background Art

[0002] A gas boiler is a device that uses gas (such as natural gas, liquefied petroleum gas, etc.) as fuel to generate heat energy through combustion, and then transfers the heat energy to a heating system or hot water system. It is a common heating and hot water device that is widely used in homes, businesses, and industries. Residential and commercial buildings choose gas boilers as heating equipment to provide comfortable indoor warmth. In the industrial field, gas boilers can be used for steam production and heating processes in power plants, chemical plants, textile mills, food processing plants, and other places. With the increasing attention to environmental protection and energy efficiency, high efficiency and energy saving of gas boilers have become an industry trend. However, the current combustion system of gas boilers is not efficient, mainly due to the following reasons: (1) Incomplete combustion of fuel. Part of the fuel cannot be fully burned during the combustion process, resulting in reduced combustion efficiency. Possible reasons include unreasonable burner design, unstable fuel supply, or uneven airflow during the combustion process; (2) Heat loss. Gas boilers generate a large amount of flue gas and heat during the combustion process. Part of the heat will be lost through flue gas emissions, loss on the boiler surface, or not fully utilized, reducing the efficiency of the combustion system; (3) Excess air. Excessive air entering the combustion system will lead to heat dilution and heat carry away, reducing combustion efficiency; (4) Inaccurate combustion control. Inaccurate control of parameters such as temperature, humidity, and fuel supply during the combustion process of gas boilers may lead to a decrease in the efficiency of the combustion system. By adopting advanced burner design and combustion technology, such as premixed burners and multi-stage burners, the heat in the flue gas can be recovered and utilized, which can improve the combustion efficiency of gas boilers and achieve a more complete combustion process. However, the use of advanced burner technology, flue gas waste heat recovery devices and intelligent control systems usually requires high technical and economic costs, which limits the ability of small and medium-sized enterprises to adopt these improvement measures.

[0003] Currently, research on improving gas combustion efficiency through the assistance of catalytic promoters has received widespread attention, and several combustion-supporting patents have been reported. For example, patent publication number CN102690696B discloses a method for preparing a nano-rare earth combustion improver for dimethyl ether gas. Cerium chloride-modified neodymium lanthanum oxide nanoparticles are prepared using a hydrothermal method as a combustion improver for dimethyl ether gas. While this combustion improver can improve the combustion efficiency of gas, it is only specific for dimethyl ether gas and cannot be used for natural gas. Patent publication number CN106147907B discloses a liquefied natural gas combustion improver. Tung oil, ethanol, n-butanol, cyclopentanol, ethylene glycol monobutyl ether, methyl ethyl ketone, borane tetrahydrofuran, etc. are combined to form a liquefied natural gas combustion improver. Although this combustion improver can increase the calorific value of gas, its composition is complex and its preparation cost is high. Summary of the Invention

[0004] The present invention aims to provide a La@Fe2O3 nanoparticle combustion improver and a preparation method of its dispersion. The combustion improver can be stably dispersed in methoxy polyvinyl alcohol glycerol ether to form a La@Fe2O3 nanoparticle combustion improver dispersion with stable properties. The dispersion can be mixed with fuel gas through a dilution spray atomization method without destroying the original boiler combustion system, thereby improving the fuel gas combustion efficiency.

[0005] To achieve the above-mentioned purpose, the present invention first provides a method for preparing La@Fe2O3 nanoparticle combustion improver, comprising the following steps:

[0006] (1) Pretreatment of Fe2O3 nanoparticles: adding Fe2O3 nanoparticles to deionized water and stirring to disperse them, adding sodium hydroxide aqueous solution to the dispersed solution and stirring to react, and after the reaction is completed, filtering, washing, and drying to obtain pretreated Fe2O3 nanoparticles;

[0007] (2) Activation of Fe2O3 nanoparticles: adding amino acids and the pretreated Fe2O3 nanoparticles obtained in step (1) to a solvent, stirring to react, and filtering, washing, and drying after the reaction to obtain activated Fe2O3 nanoparticles, wherein the amino acid comprises one of 3-aminopropionic acid, phenylalanine, and serine;

[0008] (3) Preparation of lanthanum ligand solution: adjust the pH of disodium ethylenediaminetetraacetic acid solution to 8-10 with alkali solution, and add the lanthanum salt solution dropwise to the disodium ethylenediaminetetraacetic acid solution, stir to react, and filter after the reaction is completed. The filtrate is the lanthanum ligand solution;

[0009] (4) Preparation of La@Fe2O3 nanoparticle combustion improver: Add the activated Fe2O3 nanoparticles obtained in step (2) to the lanthanum ligand solution in step (3), stir to react, filter after the reaction is completed, wash the filter residue with methanol or acetone, and dry to obtain La@Fe2O3 nanoparticle combustion improver.

[0010] The present invention uses lanthanum ions to modify iron oxide to synthesize a La@Fe2O3 nanoparticle combustion improver. The iron oxide and lanthanum ions interact, forming defect sites on the iron oxide. When the combustion improver is operating, oxygen and fuel molecules are easily adsorbed onto the defect sites on the combustion improver's surface. The lanthanum ions activate the oxygen and fuel molecules adsorbed on the combustion improver's surface, forming active substances. These substances react with each other, producing combustion products and releasing energy. The reaction mechanism is shown in the following formula.

[0011] CH4+Fe2O3→CH4@Fe2O3

[0012] O2+Fe2O3→O2@Fe2O3

[0013] O2@Fe2O3+2La 3+ →2La2O3+O@Fe2O3

[0014] CH4@Fe2O3+O@Fe2O3→CO2+H2O

[0015] In one embodiment of the present invention, in step (1), the mass volume ratio of the added Fe2O3 nanoparticles to deionized water is (1-20) kg:100 L, and the particle size of the Fe2O3 nanoparticles is 5-20 nm.

[0016] In one embodiment of the present invention, in step (1), the stirring speed during the dispersion of Fe2O3 nanoparticles is 200-500 r / min.

[0017] In one embodiment of the present invention, in step (1), the concentration of the added sodium hydroxide aqueous solution is 0.5 to 1.5 mol / L, the addition rate of the sodium hydroxide aqueous solution is 2 to 10 L / min, and the total volume of the sodium hydroxide aqueous solution added dropwise is 20 to 70 L.

[0018] In one embodiment of the present invention, in step (1), after adding the sodium hydroxide aqueous solution, the stirring speed is 200 to 500 r / min and the reaction time is 8 to 16 hours.

[0019] In one embodiment of the present invention, in step (1), the solution is concentrated using a porous ceramic membrane before filtration, and then filtered using a membrane filter press. The filter residue is washed with water and then dried at 50-70° C. for 6-12 hours.

[0020] In one embodiment of the present invention, in step (2), the solvent comprises any one of methanol, ethanol, tetrahydrofuran, and dimethylformamide, or a mixture of several thereof, and the amino acid is preferably 3-aminopropionic acid.

[0021] In one embodiment of the present invention, in step (2), the mass volume ratio of the amino acid to the solvent is (3-30) kg:100 L, and the mass volume ratio of the pretreated Fe2O3 nanoparticles to the solvent is (1-4) kg:100 L.

[0022] In one embodiment of the present invention, in step (2), the stirring reaction time is 8 to 14 hours, and the product is concentrated using a porous ceramic membrane before filtration. After concentration, the product is filtered using a diaphragm filter press, and the filter residue is washed with water and dried at 50 to 70° C. for 6 to 12 hours.

[0023] In one embodiment of the present invention, in step (3), the mass concentration of the disodium edetate solution is 0.05-0.3 kg / L, the alkali solution is a sodium hydroxide aqueous solution, and the concentration of the sodium hydroxide aqueous solution is 0.5-1.5 mol / L.

[0024] In one embodiment of the present invention, in step (3), the lanthanum salt includes lanthanum trichloride or lanthanum nitrate, and the mass concentration of the lanthanum salt in the lanthanum salt solution is 0.025 to 0.2 kg / L.

[0025] In one embodiment of the present invention, in step (3), the dropwise addition rate of the lanthanum salt solution is 5 to 10 L / min, the rotation speed during stirring is 100 to 200 r / min, and the stirring reaction time is 4 to 12 h.

[0026] In one embodiment of the present invention, in step (4), the mass volume ratio of the activated Fe2O3 nanoparticles to the lanthanum ligand solution is (1-2) g:10L.

[0027] In one embodiment of the present invention, in step (4), before the stirring reaction, hydrochloric acid or sodium hydroxide is used to adjust the pH of the solution to 7-9, the rotation speed during the stirring reaction is 100-600 r / min, the reaction time is 4-16 h, and the reaction temperature is 25-90°C.

[0028] In one embodiment of the present invention, in step (4), the solution is concentrated using a porous ceramic membrane before filtration, and then filtered using a membrane filter press. The filter residue is washed with a solvent and then dried at 50-70° C. for 6-12 hours.

[0029] The present invention also provides a La@Fe2O3 nanoparticle combustion improver prepared by the above preparation method.

[0030] The present invention also provides a method for preparing a La@Fe2O3 nanoparticle combustion-improving agent dispersion, comprising the following steps:

[0031] (1) Preparation of chloropolyethylene glycol monomethyl ether: Polyethylene glycol monomethyl ether and pyridine are added to an organic solvent, and dichlorothionyl is added dropwise while stirring. After the addition is complete, the reaction is stirred for 4 to 8 hours, and the solvent is removed to obtain chloropolyethylene glycol monomethyl ether;

[0032] (2) Synthesis of methoxypolyvinyl alcohol glycerol ether: adding the chloropolyethylene glycol monomethyl ether obtained in step (1) to an organic solvent, and simultaneously adding sodium hydroxide and acetone acetal thereto, stirring to react, adjusting the pH of the reaction mixture to make the mixture acidic, and continuing to stir the reaction. After the reaction is completed, removing the solvent, dissolving the residue with an organic solvent, filtering, and removing the solvent from the filtrate to obtain methoxypolyvinyl alcohol glycerol ether;

[0033] (3) Preparation of La@Fe2O3 nanoparticle combustion-supporting agent dispersion: La@Fe2O3 nanoparticle combustion-supporting agent is dispersed in water, and methoxy polyvinyl alcohol glycerol ether obtained in step (2) is added thereto, and the La@Fe2O3 nanoparticle combustion-supporting agent dispersion is obtained after stirring and reacting.

[0034] In one embodiment of the present invention, in step (1), the organic solvent includes at least one of dichloromethane, chloroform, tetrahydrofuran, and N,N-dimethylformamide.

[0035] In one embodiment of the present invention, in step (1), the molecular weight of the polyethylene glycol monomethyl ether is 600-2000, and the mass volume ratio of the polyethylene glycol monomethyl ether to the organic solvent is (1-2) kg:10L.

[0036] In one embodiment of the present invention, in step (1), the mass volume ratio of pyridine to organic solvent is (0.5-2):100L.

[0037] In one embodiment of the present invention, in step (1), the stirring speed during both times is 200-500 r / min, the volume ratio of the added thionyl chloride to the organic solvent is (2-15):10, and the dropping speed is 0.5-2 L / min.

[0038] In one embodiment of the present invention, in step (1), the solvent is removed by vacuum distillation at a temperature of 50 to 80°C.

[0039] In one embodiment of the present invention, in step (2), when dissolving chloropolyethylene glycol monomethyl ether in an organic solvent, the organic solvent comprises at least one of dichloromethane, chloroform, tetrahydrofuran, and N,N-dimethylformamide, preferably N,N-dimethylformamide.

[0040] In one embodiment of the present invention, in step (2), the mass volume ratio of the chloropolyethylene glycol monomethyl ether to the organic solvent is (1-2) kg:10 L, the mass volume ratio of the sodium hydroxide to the organic solvent is (1-5) kg:100 L, and the mass volume ratio of the acetone acetal to the organic solvent is (8-15) kg:100 L.

[0041] In one embodiment of the present invention, in step (2), the rotation speed during the stirring reaction is 200-500 r / min, and hydrochloric acid is used to adjust the pH of the reaction mixture to 1-3.

[0042] In one embodiment of the present invention, in step (2), when an organic solvent is used to dissolve the residue, the organic solvent includes at least one of dichloromethane, chloroform, tetrahydrofuran, and N,N-dimethylformamide, preferably chloroform.

[0043] In one embodiment of the present invention, in step (3), the mass ratio of the La@Fe2O3 nanoparticle combustion improver to water is 1:(0.1-0.4).

[0044] In one embodiment of the present invention, in step (3), after adding methoxy polyvinyl alcohol glycerol ether, the concentration of the methoxy polyvinyl alcohol glycerol ether is 2 to 20%.

[0045] The present invention also provides a La@Fe2O3 nanoparticle combustion-improving agent dispersion prepared by the above method.

[0046] The present invention also provides an application of a La@Fe2O3 nanoparticle combustion-supporting agent dispersion in the field of heating and heat supply.

[0047] The present invention also provides a method for using a La@Fe2O3 nanoparticle combustion-supporting agent dispersion liquid, wherein the La@Fe2O3 nanoparticle combustion-supporting agent dispersion liquid is sprayed through a sprayer and atomized in the boiler combustion area, with the spray amount being 0.1-0.5 kg of combustion-supporting agent dispersion liquid per cubic meter of gas.

[0048] Beneficial effects of the present invention

[0049] (1) The present invention prepares a La@Fe2O3 nanoparticle combustion improver with enhanced oxygen molecule activity. There are defect sites on the surface of the combustion improver. When the combustion improver is working, oxygen and fuel molecules are easily adsorbed onto the defect sites on the surface of the combustion improver. Lanthanum ions can activate the oxygen and fuel molecules adsorbed on the surface of the combustion improver to form active substances. The active substances react with each other to produce combustion products and release energy. The La@Fe2O3 nanoparticle combustion improver prepared by the method of the present invention helps to promote the combustion of fuel gas, thereby increasing the combustion efficiency of the fuel gas.

[0050] (2) The La@Fe2O3 nanoparticle combustion aid is reacted with methoxy polyvinyl alcohol glycerol ether to form a combustion aid dispersion. The dispersion has strong stability. From the results of the static sedimentation test, it can be seen that the dispersion stability period of the combustion aid dispersion exceeds 6 months. When the combustion aid dispersion is diluted to a weight percentage concentration of 0.1-0.3%, the La@Fe2O3 nanoparticle combustion aid can pass through a 3μm microporous filter membrane (based on the amount of water used in the preparation), which can effectively prevent the La@Fe2O3 nanoparticles from clogging during use.

[0051] (3) The present invention sprays and atomizes the La@Fe2O3 nanoparticle combustion-supporting agent dispersion so that it is mixed with the fuel gas for combustion. The combustion-supporting agent dispersion can promote the combustion reaction, thereby improving the combustion efficiency and reducing the emission of harmful substances such as nitrogen oxides.

[0052] (4) By spraying the La@Fe2O3 nanoparticle combustion-supporting agent dispersion into the combustion area of ​​the boiler to form atomization to promote combustion, the equipment investment is small and the operation is convenient. The La@Fe2O3 nanoparticle combustion-supporting agent dispersion obtained by the present invention can increase the gas combustion efficiency by 8 to 12%. DETAILED DESCRIPTION

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0054] The Fe2O3 nanoparticles used in the examples of the present invention are produced by Shanghai Yaotian New Materials Technology Co., Ltd., with a particle size range of 5 to 20 nm; 3-aminopropionic acid is produced by Henan Baichuang Biotechnology Co., Ltd.; lanthanum trichloride and lanthanum nitrate are produced by Zibo Ruibokang Rare Earth Materials Co., Ltd.; disodium ethylenediaminetetraacetic acid is produced by Jiangsu Duoyuansu Biotechnology Co., Ltd.; polyethylene glycol monomethyl ether is produced by Jiangsu Hai'an Petrochemical Plant, with a molecular weight of 600; pyridine is produced by Liaocheng Tongda Chemical Co., Ltd.; thionyl chloride is produced by Tianjin Ruimingwei Chemical Co., Ltd.; N,N-dimethylformamide is produced by Shandong Maojun Chemical Technology Co., Ltd.; and glycerol acetone acetal is produced by Wuhan Huaxiang Kejie Biotechnology Co., Ltd. The porous ceramic membrane used in the examples of the present invention is a PL-T*4 product produced by Anhui Pulang Membrane Technology Co., Ltd., with a filtration accuracy of 30-50 nm. The microporous filter membrane is produced by Xinghua Sanqing Filtration Equipment Manufacturing Co., Ltd. The sprayer used in the present invention is a FZ-6 model produced by Shandong Qingzhou Haili Machinery.

[0055] Static sedimentation experiment:

[0056] The prepared La@Fe2O3 nanoparticle combustion-supporting agent dispersion was allowed to stand for a period of time at room temperature, and the stability of the dispersion was determined by judging whether precipitation was generated in the dispersion.

[0057] Example 1

[0058] A method for preparing a La@Fe2O3 nanoparticle combustion improver comprises the following steps:

[0059] (1) Pretreatment of Fe2O3 nanoparticles: 500L of deionized water was placed in a 1000L stirred tank, and then 100kg of Fe2O3 nanoparticles was added. Under mechanical stirring (200r / min), 50L of 1.5mol / L sodium hydroxide aqueous solution was added dropwise at a rate of 5L / min. After the addition was completed, the reaction was continued to stir at room temperature for 8 hours. After the reaction was completed, the reaction mixture was concentrated through a porous ceramic membrane and filtered with a diaphragm filter press. The filter cake was repeatedly beaten and washed with water three times and then dried at 70°C for 6 hours to obtain pretreated Fe2O3 nanoparticles;

[0060] (2) Activation of Fe2O3 nanoparticles: 500 L of methanol, 100 kg of 3-aminopropionic acid, and 10 kg of the pretreated Fe2O3 nanoparticles obtained in step (1) were added to a 1000 L stirred tank, and the mixture was stirred and reacted at room temperature for 8 hours. After the reaction, the reaction mixture was concentrated through a porous ceramic membrane and filtered through a membrane filter press. The filter cake was repeatedly beaten and washed with water three times and then dried at 50°C for 12 hours to obtain activated Fe2O3 nanoparticles.

[0061] (3) Preparation of lanthanum ligand solution: Add 20kg of lanthanum trichloride and 150L of deionized water to a 200L stirred tank to prepare a lanthanum salt solution. In a 500L stirred tank, put 100L of deionized water and 30kg of disodium ethylenediaminetetraacetic acid, stir and dissolve, and adjust the pH value of the disodium ethylenediaminetetraacetic acid solution to 8 with 1mol / L sodium hydroxide aqueous solution. Under stirring conditions (stirring speed is 100r / min), add the lanthanum salt solution dropwise to the disodium ethylenediaminetetraacetic acid solution, control the dropwise addition speed to 5L / min, and the temperature to room temperature. After the addition is completed, continue to stir and react at room temperature for 4 hours. After the reaction is completed, filter with a porous ceramic membrane to remove the residue to obtain a lanthanum ligand solution;

[0062] (4) Preparation of La@Fe2O3 nanoparticle combustion improver: In a 200L stirred tank, 100L of the lanthanum ligand solution obtained in step (3) was placed, and 20kg of the activated Fe2O3 nanoparticles obtained in step (2) were added at the same time. The pH value was adjusted to 9 with 1mol / L sodium hydroxide solution. The reaction temperature was controlled at 40°C, and the reaction was stirred (600r / min) for 16 hours. After the reaction was completed, the reaction mixture was concentrated through a porous ceramic membrane and filtered through a diaphragm filter press. The filter cake was repeatedly beaten and washed three times with methanol and acetone respectively. The washed filter cake was dried at 50°C for 6 hours to obtain La@Fe2O3 nanoparticle combustion improver.

[0063] A method for preparing a La@Fe2O3 nanoparticle combustion-supporting agent dispersion comprises the following steps:

[0064] (1) Preparation of chloropolyethylene glycol monomethyl ether: In a 200L stirred tank, 100L of dichloromethane, 12kg of polyethylene glycol monomethyl ether and 0.5kg of pyridine were placed. Under stirring (200r / min), 50L of dichlorothionyl was added dropwise at a rate of 1.5L / min. After the addition was completed, the mixture was stirred at room temperature (200r / min) and reacted for 8 hours. -3 The solvent was removed by vacuum distillation under a pressure of 400 kPa to obtain chloropolyethylene glycol monomethyl ether.

[0065] (2) Place 100 L of N,N-dimethylformamide in a 200 L stirred tank, add 20 kg of chloropolyethylene glycol monomethyl ether obtained in step (1), 5 kg of sodium hydroxide and 8 kg of acetone acetal, and stir (200 r / min) at 10 ° C for 10 hours. Adjust the pH value of the reaction mixture to 3 with 1 mol / L hydrochloric acid, and continue stirring (200 r / min) for 8 hours. After the reaction is completed, the reaction mixture is stirred at 50 ° C and 0.133*10 -5 The solvent was removed by vacuum distillation under a pressure of kPa, the residue was dissolved with chloroform, and the filtrate was filtered through a porous ceramic membrane. The filtrate was heated at 50 ° C and 0.133*10-5 After removing the solvent by vacuum distillation under a pressure of 5.5 kPa, methoxy polyvinyl alcohol glycerol ether was obtained.

[0066] (3) Preparation of La@Fe2O3 nanoparticle combustion-supporting agent dispersion: 100 L of tap water and La@Fe2O3 nanoparticles were placed in a 200 L stirred tank, with the weight ratio of tap water to La@Fe2O3 nanoparticles being 1:0.3. The methoxy polyvinyl alcohol glycerol ether obtained in step (2) was added to make the concentration of methoxy polyvinyl alcohol glycerol ether 10%. The mixture was stirred at room temperature (500 r / min) for 1.0 hour to obtain a La@Fe2O3 nanoparticle combustion-supporting agent dispersion.

[0067] The static sedimentation experiment proves that its dispersion stability period exceeds 6 months, and it can pass through a 3μm microporous filter membrane when diluted to a weight percentage concentration of 0.2% (based on the amount of water used in preparation).

[0068] A method for using a La@Fe2O3 nanoparticle combustion-supporting agent dispersion is disclosed. The La@Fe2O3 nanoparticle combustion-supporting agent dispersion obtained in this embodiment is diluted to a weight percentage concentration of 0.2%, and then sprayed through a sprayer to form an atomized product in the combustion area of ​​the boiler. The spray amount is 0.5 kg of La@Fe2O3 nanoparticles per cubic meter of gas. The combustion-supporting agent dispersion is applied to a vertical fully automatic oil (gas) steam boiler of Changzhou Zhongna Chemical Co., Ltd., model: LHS0.3-0.4(0.7)-Y(Q), rated evaporation capacity: 0.3 t / h, rated steam pressure: 0.7 MPa, and heating area: 7.32 m 2 .

[0069] Calculated based on the average daily gas consumption, the gas combustion efficiency increased by 8% after the injection of La@Fe2O3 nanoparticle combustion aid dispersion.

[0070] Example 2

[0071] A method for preparing a La@Fe2O3 nanoparticle combustion improver comprises the following steps:

[0072] (1) Pretreatment of Fe2O3 nanoparticles: 500L of deionized water was placed in a 1000L stirred tank, and then 75kg of Fe2O3 nanoparticles were added. Under mechanical stirring (500r / min), 40L of 1.0mol / L sodium hydroxide aqueous solution was added dropwise at a rate of 8L / min. After the addition was completed, the reaction was continued to stir at room temperature for 14 hours. After the reaction was completed, the reaction mixture was concentrated through a porous ceramic membrane and filtered through a diaphragm filter press. The filter cake was repeatedly beaten and washed with water three times and then dried at 60°C for 10 hours to obtain pretreated Fe2O3 nanoparticles;

[0073] (2) Activation of Fe2O3 nanoparticles: 500 L of dimethylformamide, 100 kg of 3-aminopropionic acid, and 15 kg of the pretreated Fe2O3 nanoparticles obtained in step (1) were added to a 1000 L stirred tank, and the mixture was stirred and reacted at room temperature for 10 hours. After the reaction, the reaction mixture was concentrated through a porous ceramic membrane and filtered through a membrane filter press. The filter cake was repeatedly beaten and washed with water three times and then dried at 60°C for 10 hours to obtain activated Fe2O3 nanoparticles.

[0074] (3) Preparation of lanthanum ligand solution: Add 12kg of lanthanum nitrate and 150L of deionized water to a 200L stirred tank to prepare a lanthanum salt solution. In a 500L stirred tank, put 100L of deionized water and 25kg of disodium ethylenediaminetetraacetic acid, stir and dissolve, and adjust the pH value of the disodium ethylenediaminetetraacetic acid solution to 10 with 1mol / L sodium hydroxide aqueous solution. Under stirring conditions (stirring speed is 100r / min), the lanthanum salt solution is added dropwise to the disodium ethylenediaminetetraacetic acid solution, and the dropwise addition speed is controlled to 8L / min and the temperature is room temperature. After the addition is completed, continue to stir and react at room temperature for 6 hours. After the reaction is completed, filter with a porous ceramic membrane to remove the residue to obtain a lanthanum ligand solution;

[0075] (4) Preparation of La@Fe2O3 nanoparticle combustion improver: In a 200L stirred tank, 100L of the lanthanum ligand solution obtained in step (3) was placed, and 13kg of the activated Fe2O3 nanoparticles obtained in step (2) were added at the same time. The pH value was adjusted to 8 with 1mol / L sodium hydroxide solution. The reaction temperature was controlled at 60°C and the reaction was stirred (400r / min) for 14 hours. After the reaction was completed, the reaction mixture was concentrated through a porous ceramic membrane and filtered through a diaphragm filter press. The filter cake was repeatedly beaten and washed three times with methanol and acetone respectively. The washed filter cake was dried at 55°C for 8 hours to obtain La@Fe2O3 nanoparticle combustion improver.

[0076] A method for preparing a La@Fe2O3 nanoparticle combustion-supporting agent dispersion comprises the following steps:

[0077] (1) Preparation of chloropolyethylene glycol monomethyl ether: In a 200L stirred tank, 100L of dichloromethane, 15kg of polyethylene glycol monomethyl ether and 1kg of pyridine were placed. Under stirring (300r / min), 100L of dichlorothionyl was added dropwise at a rate of 1.5L / min. After the addition was completed, the mixture was stirred at room temperature (300r / min) and reacted for 6 hours. -6 The solvent was removed by vacuum distillation under a pressure of 400 kPa to obtain chloropolyethylene glycol monomethyl ether.

[0078] (2) 100 L of N, N-dimethylformamide was placed in a 200 L stirred tank, and 15 kg of chloropolyethylene glycol monomethyl ether obtained in step (1), 5 kg of sodium hydroxide and 13 kg of acetone acetal were added. The mixture was stirred (300 r / min) at 20 ° C for 8 hours. The pH value of the reaction mixture was adjusted to 2 with 1 mol / L hydrochloric acid, and the reaction was continued with stirring (200 r / min) for 7 hours. After the reaction was completed, the reaction mixture was heated at 50 ° C and 0.133*10 -6 The solvent was removed by vacuum distillation under a pressure of kPa, the residue was dissolved with chloroform, and the filtrate was filtered through a porous ceramic membrane. The filtrate was heated at 50 ° C and 0.133*10 -6 After removing the solvent by vacuum distillation under a pressure of 5.5 kPa, methoxy polyvinyl alcohol glycerol ether was obtained.

[0079] (3) Preparation of La@Fe2O3 nanoparticle combustion-supporting agent dispersion: 100 L of tap water and La@Fe2O3 nanoparticles were placed in a 200 L stirred tank, with the weight ratio of tap water to La@Fe2O3 nanoparticles being 1:0.2. The methoxypolyvinyl alcohol glycerol ether obtained in step (2) was added to make the concentration of methoxypolyvinyl alcohol glycerol ether 13%. The mixture was stirred at room temperature (500 r / min) for 0.8 h to obtain a La@Fe2O3 nanoparticle combustion-supporting agent dispersion.

[0080] The static sedimentation experiment proves that its dispersion stability period exceeds 6 months, and it can pass through a 3 μm microporous filter membrane when diluted to a weight percentage concentration of 0.1% (based on the amount of water used in preparation).

[0081] A method for using a La@Fe2O3 nanoparticle combustion-supporting agent dispersion obtained in this example is disclosed. The La@Fe2O3 nanoparticle combustion-supporting agent dispersion obtained in this example is diluted to a weight percent concentration of 0.1%. The dispersion is then sprayed through a sprayer to form an atomized atomized liquid in the boiler combustion area, with an injection rate of 0.4 kg of La@Fe2O3 nanoparticles per cubic meter of fuel gas. The combustion-supporting agent dispersion is applied to a YYL(W) oil-fired (or gas-fired) organic carrier boiler, model YYL(W)-3500Y(Q), manufactured by Suzhou Zhongyong Environmental Protection Technology Co., Ltd., with a rated calorific value of 300 kCal, a rated steam pressure of 0.8 MPa, and a maximum operating temperature of 320°C.

[0082] Calculated based on the average daily gas consumption, the gas combustion efficiency increased by 11.5% after spraying the La@Fe2O3 nanoparticle combustion aid dispersion.

[0083] Example 3

[0084] A method for preparing a La@Fe2O3 nanoparticle combustion improver comprises the following steps:

[0085] (1) Pretreatment of Fe2O3 nanoparticles: 500L of deionized water was placed in a 1000L stirred tank, and then 100kg of Fe2O3 nanoparticles was added. Under mechanical stirring (300r / min), 60L of 1.5mol / L sodium hydroxide aqueous solution was added dropwise at a rate of 8L / min. After the addition was completed, the reaction was continued to stir at room temperature for 10 hours. After the reaction was completed, the reaction mixture was concentrated through a porous ceramic membrane and filtered with a diaphragm filter press. The filter cake was repeatedly beaten and washed with water three times and then dried at 70°C for 7 hours to obtain pretreated Fe2O3 nanoparticles;

[0086] (2) Activation of Fe2O3 nanoparticles: 500 L of tetrahydrofuran, 70 kg of 3-aminopropionic acid, and 10 kg of the pretreated Fe2O3 nanoparticles obtained in step (1) were added to a 1000 L stirred tank, and the mixture was stirred and reacted at room temperature for 14 hours. After the reaction, the reaction mixture was concentrated through a porous ceramic membrane and filtered through a membrane filter press. The filter cake was repeatedly beaten and washed with water three times and then dried at 50°C for 10 hours to obtain activated Fe2O3 nanoparticles.

[0087] (3) Preparation of lanthanum ligand solution: Add 16 kg of lanthanum nitrate and 200 L of deionized water to a 200 L stirred tank to prepare a lanthanum salt solution. In a 500 L stirred tank, put 100 L of deionized water and 15 kg of disodium ethylenediaminetetraacetic acid, stir and dissolve, and adjust the pH value of the disodium ethylenediaminetetraacetic acid solution to 9 with 1 mol / L sodium hydroxide aqueous solution. Under stirring conditions (stirring speed is 200 r / min), add the lanthanum salt solution dropwise to the disodium ethylenediaminetetraacetic acid solution, control the dropwise addition speed to 10 L / min, and the temperature to room temperature. After the addition is completed, continue to stir and react at room temperature for 10 hours. After the reaction is completed, filter with a porous ceramic membrane to remove the residue to obtain a lanthanum ligand solution;

[0088] (4) Preparation of La@Fe2O3 nanoparticle combustion improver: In a 200L stirred tank, 100L of the lanthanum ligand solution obtained in step (3) was placed, and 16kg of the activated Fe2O3 nanoparticles obtained in step (2) were added at the same time. The pH value was adjusted to 9 with 1mol / L sodium hydroxide solution. The reaction temperature was controlled at 40°C, and the reaction was stirred (300r / min) for 10 hours. After the reaction was completed, the reaction mixture was concentrated through a porous ceramic membrane and filtered through a diaphragm filter press. The filter cake was repeatedly beaten and washed three times with methanol and acetone respectively. The washed filter cake was dried at 70°C for 10 hours to obtain La@Fe2O3 nanoparticle combustion improver.

[0089] A method for preparing a La@Fe2O3 nanoparticle combustion-supporting agent dispersion comprises the following steps:

[0090] (1) Preparation of chloropolyethylene glycol monomethyl ether: In a 200L stirred tank, 100L of dichloromethane, 20kg of polyethylene glycol monomethyl ether and 2kg of pyridine were placed. Under stirring (500r / min), 150L of dichlorothionyl was added dropwise at a rate of 2L / min. After the addition was completed, the mixture was stirred at room temperature (500r / min) and reacted for 8 hours. -5 The solvent was removed by vacuum distillation under a pressure of 400 kPa to obtain chloropolyethylene glycol monomethyl ether.

[0091] (2) 100 L of N, N-dimethylformamide was placed in a 200 L stirred tank, and 20 kg of chloropolyethylene glycol monomethyl ether obtained in step (1), 4 kg of sodium hydroxide and 15 kg of acetone acetal were added. The mixture was stirred at 25 ° C (500 r / min) for 6 hours. The pH value of the reaction mixture was adjusted to 3 with 1 mol / L hydrochloric acid, and the reaction was continued at 500 r / min for 8 hours. After the reaction was completed, the reaction mixture was stirred at 50 ° C and 0.133*10 -5 The solvent was removed by vacuum distillation under a pressure of kPa, the residue was dissolved with chloroform, and the filtrate was filtered through a porous ceramic membrane. The filtrate was heated at 50 ° C and 0.133*10 -5 After removing the solvent by vacuum distillation under a pressure of 5.5 kPa, methoxy polyvinyl alcohol glycerol ether was obtained.

[0092] (3) Preparation of La@Fe2O3 nanoparticle combustion-supporting agent dispersion: 100 L of tap water and La@Fe2O3 nanoparticles were placed in a 200 L stirred tank, with the weight ratio of tap water to La@Fe2O3 nanoparticles being 1:0.4. The methoxypolyvinyl alcohol glycerol ether obtained in step (2) was added to make the concentration of methoxypolyvinyl alcohol glycerol ether 20%. The mixture was stirred at room temperature (500 r / min) for 1 hour to obtain a La@Fe2O3 nanoparticle combustion-supporting agent dispersion.

[0093] The static sedimentation experiment proves that its dispersion stability period exceeds 6 months, and it can pass through a 3 μm microporous filter membrane when diluted to a weight percentage concentration of 0.1% (based on the amount of water used in preparation).

[0094] A method for using a La@Fe2O3 nanoparticle combustion-supporting agent dispersion obtained in this example is disclosed. The La@Fe2O3 nanoparticle combustion-supporting agent dispersion obtained in this example is diluted to a weight percent concentration of 0.1%. The dispersion is then sprayed through a sprayer to form an atomized liquid in the combustion area of ​​a boiler, with a spray rate of 0.5 kg of La@Fe2O3 nanoparticles per cubic meter of gas. The combustion-supporting agent dispersion is applied to a horizontal vacuum hot water boiler, model ZKW2.1, manufactured by Tai'an Weiye Electromechanical Technology Co., Ltd., with a rated heating capacity of 2.1 MW and a rated steam pressure of 1.25 MPa.

[0095] Calculated based on the average daily gas consumption, the gas combustion efficiency increased by 12% after spraying the La@Fe2O3 nanoparticle combustion aid dispersion.

Claims

1. A method for preparing La@Fe2O3 nanoparticle combustion improver, characterized in that: The following steps are involved: (1) Pretreatment of Fe2O3 nanoparticles: adding Fe2O3 nanoparticles to deionized water, stirring to disperse them, adding sodium hydroxide aqueous solution to the dispersed solution, stirring to react them, filtering, washing, and drying after the reaction is completed to obtain pretreated Fe2O3 nanoparticles, wherein the mass volume ratio of the added Fe2O3 nanoparticles to the deionized water is (1-20) kg:100 L, the particle size of the Fe2O3 nanoparticles is 5-20 nm, the concentration of the added sodium hydroxide aqueous solution is 0.5-1.5 mol / L, the addition rate of the sodium hydroxide aqueous solution is 2-10 L / min, and the total volume of the added sodium hydroxide aqueous solution is 20-70 L; (2) Activation of Fe2O3 nanoparticles: adding amino acids and the pretreated Fe2O3 nanoparticles obtained in step (1) to a solvent, stirring to react, and filtering, washing, and drying after the reaction to obtain activated Fe2O3 nanoparticles, wherein the amino acid comprises one of 3-aminopropionic acid, phenylalanine, and serine; (3) Preparation of lanthanum ligand solution: adjusting the pH of disodium ethylenediaminetetraacetic acid solution to 8-10 with alkali solution, and adding the lanthanum salt solution dropwise to the disodium ethylenediaminetetraacetic acid solution, stirring to react, filtering after the reaction is completed, and the filtrate is the lanthanum ligand solution, wherein the mass concentration of the disodium ethylenediaminetetraacetic acid solution is 0.05-0.3 kg / L, the lanthanum salt includes lanthanum trichloride or lanthanum nitrate, the mass concentration of the lanthanum salt in the lanthanum salt solution is 0.025-0.2 kg / L, and the dropping speed of the lanthanum salt solution is 5-10 L / min; (4) Preparation of La@Fe2O3 nanoparticle combustion improver: Add the activated Fe2O3 nanoparticles obtained in step (2) to the lanthanum ligand solution in step (3), stir to react, filter after the reaction is completed, wash the filter residue with methanol and / or acetone, and dry to obtain La@Fe2O3 nanoparticle combustion improver.

2. The preparation method according to claim 1, characterized in that In step (2), the solvent includes any one or a mixture of methanol, ethanol, tetrahydrofuran, and dimethylformamide, the mass volume ratio of the amino acid to the solvent is (3-30) kg:100 L, the mass volume ratio of the pretreated Fe2O3 nanoparticles to the solvent is (1-4) kg:100 L, and the amino acid is 3-aminopropionic acid.

3. The preparation method according to claim 1, characterized in that In step (4), the mass volume ratio of the activated Fe2O3 nanoparticles to the lanthanum ligand solution is (1-2) g:10L. Before the stirring reaction, the pH of the solution is adjusted to 7-9 using hydrochloric acid or sodium hydroxide. The rotation speed during the stirring reaction is 100-600 r / min, the reaction time is 4-16 h, and the reaction temperature is 25-90°C.

4. The La@Fe2O3 nanoparticle combustion improver prepared by the preparation method according to any one of claims 1 to 3.

5. A method for preparing a La@Fe2O3 nanoparticle combustion-supporting agent dispersion, characterized in that: The following steps are involved: (1) Preparation of chloropolyethylene glycol monomethyl ether: Polyethylene glycol monomethyl ether and pyridine are added to an organic solvent, and dichlorothionyl is added dropwise while stirring. After the addition is complete, the reaction is stirred for 4 to 8 hours, and the solvent is removed to obtain chloropolyethylene glycol monomethyl ether; (2) Synthesis of methoxypolyvinyl alcohol glycerol ether: adding the chloropolyethylene glycol monomethyl ether obtained in step (1) to an organic solvent, and simultaneously adding sodium hydroxide and acetone acetal thereto, stirring to react, adjusting the pH of the reaction mixture to make the mixture acidic, and continuing to stir the reaction. After the reaction is completed, removing the solvent, dissolving the residue with an organic solvent, filtering, and removing the solvent from the filtrate to obtain methoxypolyvinyl alcohol glycerol ether; (3) Preparation of La@Fe2O3 nanoparticle combustion-supporting agent dispersion: The La@Fe2O3 nanoparticle combustion-supporting agent according to claim 4 is dispersed in water, and the methoxy polyvinyl alcohol glycerol ether obtained in step (2) is added thereto, and the La@Fe2O3 nanoparticle combustion-supporting agent dispersion is obtained after stirring and reacting; Wherein, the organic solvent includes at least one of dichloromethane, chloroform, tetrahydrofuran, and N,N-dimethylformamide. In step (1), the molecular weight of the polyethylene glycol monomethyl ether is 600-2000, the mass volume ratio of the polyethylene glycol monomethyl ether to the organic solvent is (1-2) kg:10L, and the mass volume ratio of the pyridine to the organic solvent is (0.5-2):100L.

6. The preparation method according to claim 5, characterized in that In step (2), the mass volume ratio of the chloropolyethylene glycol monomethyl ether to the organic solvent is (1-2) kg:10 L, the mass volume ratio of the sodium hydroxide to the organic solvent is (1-5) kg:100 L, the mass volume ratio of the acetone acetal to the organic solvent is (8-15) kg:100 L, and the pH of the mixed solution is 1-3.

7. The preparation method according to claim 5, characterized in that In step (3), the mass ratio of the La@Fe2O3 nanoparticles to water is 1:(0.1-0.4), and after the methoxy polyvinyl alcohol glycerol ether is added, the concentration of the methoxy polyvinyl alcohol glycerol ether is 2-20%.

8. The La@Fe2O3 nanoparticle combustion-supporting agent dispersion prepared according to the preparation method according to any one of claims 5 to 7.

9. Use of the La@Fe2O3 nanoparticle combustion-supporting agent dispersion according to claim 8 in the field of heating and heat supply.

10. A method for using the La@Fe2O3 nanoparticle combustion-supporting agent dispersion according to claim 8, characterized in that: The La@Fe2O3 nanoparticle combustion-supporting agent dispersion is sprayed through a sprayer and atomized in the combustion area of ​​the boiler, with the spraying amount being 0.1-0.5 kg of the combustion-supporting agent dispersion per cubic meter of gas.