Aza-tetraphenylcyclobutane rare earth gas combustion additive and preparation method thereof

Abstract

The application discloses a rare earth nitrogen tetraphenylcyclo-tetracarboxylic acid gas combustion aid and a preparation method thereof, which comprises three steps of preparing a nitrogen tetraphenylcyclo ring by using dimethylbenzene, 2,7-diamino fluorene, sodium bicarbonate and dibromoethane, preparing nitrogen tetraphenylcyclo-tetracarboxylic acid by using the nitrogen tetraphenylcyclo ring, dimethyl sulfoxide, sodium methoxide and allyl chloride, and preparing the rare earth nitrogen tetraphenylcyclo-tetracarboxylic acid gas combustion aid by using the nitrogen tetraphenylcyclo-tetracarboxylic acid, ferrocene, rare earth chloride and an organic solvent. The rare earth nitrogen tetraphenylcyclo-tetracarboxylic acid gas combustion aid prepared by the method is sprayed into a boiler combustion area in a misting mode to promote combustion, so that the gas combustion efficiency is increased by 10-16%, and the method has the advantages of less equipment investment, convenient operation and the like.

Description

Technical Field

[0001] This invention relates to a rare earth combustion aid for aza-tetrafluorenecyclotetracarboxylic acid fuel and its preparation method, belonging to the field of fuel catalysts. Background Technology

[0002] A gas-fired boiler is a boiler device that uses gas as its energy source. It typically consists of a burner, furnace, heat exchanger, and control system. It boasts advantages such as high efficiency, environmental friendliness, safety, and reliability, and is widely used in industrial, commercial, and residential sectors. The principle of a gas-fired boiler is to utilize the high-temperature flue gas generated by the combustion of gas, transferring heat to water or other media through a heat exchanger to heat them to the desired temperature. This type of boiler includes gas-fired hot water boilers, gas-fired hot water boilers, and gas-fired steam boilers, among which gas-fired hot water boilers are also called gas-fired heating boilers or gas-fired bathing boilers. The combustion efficiency of gas-fired boilers is typically between 90% and 99%. With the adoption of fully premixed, FGR (Flue Gas Recirculation) technology, the thermal efficiency can reach approximately 100% to 108%. However, adopting fully premixed, FGR, and other combustion technologies in older boilers requires significant equipment retrofitting costs. Reasons for low combustion efficiency in gas-fired boilers may include poor fuel quality, burner adjustment issues, internal ash or scale buildup, insufficient or uneven air supply, poor gas quality, unreasonable boiler design, and improper operation management and system maintenance. The purity and calorific value of fuel gas have a significant impact on the combustion effect and thermal efficiency of gas-fired boilers. Poor fuel gas quality can lead to incomplete combustion. Impurities in the fuel gas used in gas-fired boilers mainly include tar, dust, and moisture. Tar accumulation not only affects normal combustion but can also lead to incomplete combustion, carbon buildup, and consequently, reduced boiler thermal efficiency. The crude fuel gas produced during the pyrolysis and gasification process of biomass boilers contains tar vapor impurities. Catalytic combustion of the tar using a catalyst can improve combustion effect and thermal efficiency while reducing carbon buildup.

[0003] Currently, research on improving the combustion efficiency of natural gas through catalytic additives has received widespread attention, and several combustion-enhancing patents have been reported. For example, patent CN102690696B discloses a method for preparing a nano-rare earth combustion enhancer for dimethyl ether (DME) gas. This method uses a hydrothermal process to prepare cerium chloride-modified neodymium lanthanum oxide nanoparticles as a combustion enhancer for DME gas. While this method can improve the combustion efficiency of natural gas, the prepared combustion enhancer is only suitable for DME gas and cannot be used for natural gas. Patent CN106147907B discloses a combustion enhancer for liquefied natural gas (LNG), which is formulated with tung oil, ethanol, n-butanol, cyclopentanol, ethylene glycol monobutyl ether, methyl ethyl ketone, and borane tetrahydrofuran. Although this combustion enhancer can increase the calorific value of the gas, its composition is complex and its preparation cost is high. Patent CN103160348B discloses a rare earth catalytic enhancer for light alkane fuel gas and its preparation method. The enhancer formulation consists of the following raw materials in parts by weight: 3-6 parts cerium nitrate, 0.3-0.6 parts ferrocene, 30-50 parts ethanol, 10-20 parts acetone, and 15-25 parts petroleum ether. The enhancer is prepared through steps including additive preparation, raw material mixing, and filtration. Cerium nitrate belongs to category 2 of oxidizing solids, and its high-temperature decomposition releases highly toxic nitrogen oxide gases. Ethanol and acetone are precursor chemicals for toxic substances, and their production and transportation are strictly controlled. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a rare earth combustion aid containing aza-tetrafluorenecyclotetracarboxylic acid and its preparation method, thereby solving the problems of complex composition of existing combustion aids, use of easily toxic raw materials, and low catalytic efficiency for natural gas and other fuel gases.

[0005] To achieve the above objectives, the present invention first provides a rare earth combustion aid of aza-tetrafluorenecyclotetracarboxylic acid, which has the following structure:

[0006] (I) In formula (Ⅰ), R is a rare earth ion, including any one of lanthanum (La), cerium (Ce), and europium (Eu).

[0007] This invention also provides a method for preparing a rare earth combustion aid, namely, aza-tetrafluorenecyclotetracarboxylic acid, comprising the following steps: (1) Under nitrogen protection, 2,7-diaminofluorene and sodium bicarbonate were added to xylene. After cooling to 4~10 ℃, dibromoethane was added dropwise. The reaction was stirred at 30~90 ℃ for 2~8 h. After the reaction was completed, the reaction mixture was poured into 10~15 times the volume of ice water and stirred for 5~10 min. The mixture was filtered and the precipitate was washed with water 3 times to obtain the azatetrafluorene ring. (2) Under nitrogen protection, the azatetrafluorene ring was added to dimethyl sulfoxide, and then sodium methoxide was added. After the reaction, allyl chloride was added dropwise to the reaction mixture and the reaction was stirred. After the reaction was completed, distilled water was added to the reaction mixture, filtered, and the precipitate was transferred to dichloromethane. Sodium periodate, potassium perchromate and water were added. After the reaction was completed, the reaction product was washed twice with saturated sodium chloride aqueous solution. The organic layer was dried with anhydrous Na2SO4 for 0.5~1.5h, filtered, and the solvent was removed on a vacuum rotary evaporator to obtain azatetrafluorene tetracarboxylic acid. (3) Add the azira-tetrafluorene cyclotetracarboxylic acid prepared in step (2) to an organic solvent to prepare an azira-tetrafluorene cyclotetracarboxylic acid solution, then add an aqueous solution of rare earth chloride, mix and shake for 5~30 min, let stand to separate into layers, collect the organic phase, dry with anhydrous calcium chloride for 0.5~1.5 h, and then add ferrocene to obtain azira-tetrafluorene cyclotetracarboxylic acid rare earth combustion aid.

[0008] In one embodiment of the present invention, in step (1), the mass-to-volume ratio of 2,7-diaminofluorene to xylene is (0.5~5)g:(30~100)mL, the mass-to-volume ratio of sodium bicarbonate to xylene is (0.1~0.4)g:(15~50)mL, and the volume ratio of dibromoethane to xylene is (2~25):(30~100).

[0009] In one embodiment of the present invention, in step (1), the yield of the azatetrafluorene ring is 82-97.2%.

[0010] In one embodiment of the present invention, in step (2), the mass-to-volume ratio of the azatetrafluorene ring to dimethyl sulfoxide is (1.5~3)g:(30~100)mL, and the mass-to-volume ratio of the sodium methoxide to dimethyl sulfoxide is (1~3)g:(15~50)mL.

[0011] In one embodiment of the present invention, in step (2), after adding sodium methoxide, the mixture is stirred and reacted at 25-40 °C for 30-120 min.

[0012] In one embodiment of the present invention, in step (2), the volume ratio of the added allyl chloride to dimethyl sulfoxide is (0.02~0.15):(30~100), and after adding allyl chloride, the reaction continues for 3~6 hours.

[0013] In one embodiment of the present invention, in step (2), the volume ratio of dichloromethane to dimethyl sulfoxide is 1:1, the mass-to-volume ratio of sodium periodate to dichloromethane is (1~3)g:(30~100)mL, the mass-to-volume ratio of potassium perchromate to dichloromethane is (0.5~4)g:(30~100)mL, and the volume ratio of water to dichloromethane is (1~2):(30~100). After adding sodium periodate, potassium perchromate and water, the reaction is carried out at 25~35℃ for 16~18h.

[0014] In one embodiment of the present invention, in step (2), the yield of the azatetrafluorene cyclotetracarboxylic acid is 75-85%.

[0015] In one embodiment of the present invention, in step (3), the organic solvent includes at least one of dibutyl ether, ethyl acetate, ethylene glycol dibutyl ether, and propyl acetate, preferably dibutyl ether.

[0016] In one embodiment of the present invention, in step (3), the mass concentration of the azatetrafluorene cyclotetracarboxylic acid solution is 45-55%.

[0017] In one embodiment of the present invention, in step (3), the rare earth chloride includes any one of lanthanum chloride, cerium chloride, and europium chloride, the mass concentration of the rare earth chloride in the aqueous solution of the rare earth chloride is 15-25%, and the volume ratio of the rare earth chloride aqueous solution to the organic solvent is 1:1.

[0018] In one embodiment of the present invention, after adding ferrocene in step (3), the mass concentration of ferrocene is 5-10%.

[0019] The present invention also discloses the application of the above-mentioned aza-tetrafluorenecyclotetracarboxylic acid rare earth combustion aid in catalytic combustion.

[0020] In one embodiment of the present invention, the application includes atomizing the above-mentioned aza-tetrafluorene cyclotetracarboxylic acid rare earth combustion aid in the boiler combustion zone after being sprayed by a sprayer.

[0021] In one embodiment of the present invention, the injection amount is 0.1-0.5 liters of azatetrazolium tetrafluoromethane rare earth combustion aid per cubic meter of fuel gas.

[0022] The beneficial effects of this invention are: (1) This invention first prepares azira-tetrafluorene ring and azira-tetrafluorene tetracarboxylic acid, and then uses organic solvents such as azira-tetrafluorene tetracarboxylic acid, ferrocene, rare earth chlorides and dibutyl ether to prepare azira-tetrafluorene tetracarboxylic acid rare earth combustion aid. In the preparation of the combustion aid, rare earth chlorides such as lanthanum chloride (La), cerium chloride (Ce), europium chloride (Eu) and organic solvents such as dibutyl ether are used. These raw materials are not easily manufactured toxic chemicals and do not have flammable and explosive properties. Since there is no nitro group in the rare earth chloride, it will not produce highly toxic nitrogen oxide gas after high temperature decomposition.

[0023] (2) The present invention prepares rare earth combustion additives of azira-tetrafluorene cyclotetracarboxylic acid by reacting organic solvents such as ferrocene, rare earth chlorides and dibutyl ether. The final material has a single composition, and the raw materials used in the preparation process are all conventional raw materials, so the preparation cost is not high.

[0024] (3) The preparation method of the present invention is simple. The prepared aza-tetrafluorene cyclotetracarboxylic acid has a certain combustion-supporting effect. On the other hand, the catalytic effect of rare earth elements can accelerate the decomposition of tar impurities in the gas, increase the combustion speed of the gas, reduce carbon deposits, and improve the combustion effect and thermal efficiency of the boiler.

[0025] (4) The azatetrafluorenecyclotetracarboxylic acid rare earth combustion aid prepared by the method of the present invention can be used as a combustion aid for natural gas. When promoting the combustion of natural gas, the combustion efficiency of the gas can be increased by 10-16%.

[0026] (5) The azatetrafluorene cyclotetracarboxylic acid rare earth gas combustion catalyst can be injected into the boiler combustion zone by atomization to promote combustion. It requires less equipment investment and is easy to operate. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The xylene used in the embodiments and comparative examples of this invention is from Shandong Qilin Chemical Co., Ltd., 2,7-diaminofluorene is from Hubei Baidu Chemical Co., Ltd., sodium bicarbonate is purchased from Shandong Haihua Supply Chain Co., Ltd., dibromoethane is provided by Jiangsu Bosite Chemical Technology Co., Ltd., dimethyl sulfoxide is from Changzhou Qidi Chemical Co., Ltd., sodium methoxide is from Shandong Yuanjin New Materials Co., Ltd., allyl chloride is from Shandong Duoju Chemical, dichloromethane is from Changzhou Qidi Chemical Co., Ltd., sodium periodate is purchased from Xindongneng Chemical Co., Ltd., potassium perchromate is purchased from Wuhan Jiyesheng Chemical Co., Ltd., dibutyl ether is provided by Shandong Jinyueyuan New Materials Co., Ltd., and cerium chloride, lanthanum oxide, europium oxide and anhydrous calcium chloride are provided by Ganzhou Liantuo New Materials Co., Ltd.

[0029] Example 1 A method for preparing a rare earth combustion aid containing aza-tetrafluorenecyclotetracarboxylic acid includes the following steps: (1) Under nitrogen protection, 5 g of 2,7-diaminofluorene and 0.8 g of sodium bicarbonate were added to 100 mL of xylene. After cooling to 10 °C, 25 mL of dibromoethane was added dropwise over half an hour. The mixture was then stirred at 90 °C for 8 h. After the reaction was completed, the reaction mixture was poured into 15 times its volume of ice water and stirred for 10 minutes. The mixture was then filtered, and the precipitate was washed three times with water to obtain azatetrafluorene ring with a yield of 97.2%. (2) Under nitrogen protection, 3 g of azatetrafluorene ring was added to 100 mL of dimethyl sulfoxide, followed by 6 g of sodium methoxide, and then stirred at 40 °C for 120 min. Next, 0.15 mL of allyl chloride was added dropwise to the reaction mixture, and the reaction was continued with stirring for 6 h. After the reaction was complete, 20 times the volume of distilled water was added to the reaction mixture, filtered, and the precipitate was transferred to 100 mL of dichloromethane. 3 g of sodium periodate, 4 g of potassium perchromate, and 2 mL of water were added. The reaction mixture was stirred at 35 °C for 18 h. After the reaction was complete, the reaction mixture was washed twice with 100 mL of saturated sodium chloride (Shandong Ocean Star Chemical Technology Co., Ltd.) aqueous solution. The organic layer was dried with 4 g of anhydrous Na₂SO₄ (Weifang Dakang Chemical Co., Ltd.) for 1.5 h, filtered, and the solvent was removed using a vacuum rotary evaporator to obtain azatetrafluorene ring tetracarboxylic acid with a yield of 85%. (3) Add azira-tetrafluorene cyclotetracarboxylic acid to 100 mL of dibutyl ether to prepare a 50% (w / v) dibutyl ether solution of azira-tetrafluorene cyclotetracarboxylic acid. Then add 100 mL of 20% (w / v) cerium chloride aqueous solution, mix and shake for 30 minutes, let stand to separate the layers, collect the organic phase, dry it with 10 g of anhydrous calcium chloride for 1.5 hours, and then add ferrocene to make the ferrocene mass concentration 10% to obtain the azira-tetrafluorene cyclotetracarboxylic acid rare earth gas combustion catalyst.

[0030] Application of rare earth combustion aids, such as azirmonofluorenecyclotetracarboxylic acid, in catalytic combustion.

[0031] The application site uses a vertical fully automatic oil (gas) steam boiler owned by 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, heating area: 7.32 m². 2 .

[0032] The rare earth gas combustion aid, aza-tetrafluorene cyclotetracarboxylic acid obtained in this embodiment, was atomized in the boiler combustion zone after being sprayed by a sprayer (produced by Shandong Qingzhou Haili Machinery, type FZ-6). The spraying amount was 0.5 L of aza-tetrafluorene cyclotetracarboxylic acid rare earth gas combustion aid per cubic meter of gas.

[0033] Based on the average daily gas consumption, the combustion efficiency of the gas increased by 10% after injecting the rare earth gas combustion additive, azotetrafluorenecyclotetracarboxylic acid.

[0034] Example 2 A method for preparing a rare earth combustion aid containing aza-tetrafluorenecyclotetracarboxylic acid includes the following steps: (1) Under nitrogen protection, 0.5 g of 2,7-diaminofluorene and 0.2 g of sodium bicarbonate were added to 30 mL of xylene. The mixture was cooled to 4 °C, and 5 mL of dibromoethane was added dropwise over half an hour. The reaction mixture was then stirred at 30 °C for 8 hours. After the reaction was completed, the reaction mixture was poured into 10 times its volume of ice water and stirred for 50 minutes. The mixture was then filtered, and the precipitate was washed three times with water to obtain azatetrafluorene ring in 82% yield. (2) Under nitrogen protection, 1.5 g of azatetrafluorene ring was added to 30 mL of dimethyl sulfoxide, followed by 2 g of sodium methoxide, and then stirred at 25 °C for 30 minutes. Next, 0.02 mL of allyl chloride was added dropwise to the reaction mixture, and the reaction was stirred for another 3 h. After the reaction was complete, 10 times the volume of distilled water was added to the reaction mixture, and the mixture was filtered. The precipitate was transferred to 30 mL of dichloromethane, and 1 g of sodium periodate, 0.5 g of potassium perchromate, and 1 mL of water were added. The mixture was stirred at 25 °C for 16 h. After the reaction was complete, the reaction mixture was washed twice with 50 mL of saturated sodium chloride aqueous solution. The organic layer was dried with 2 g of anhydrous Na2SO4 for 0.5 h, filtered, and the solvent was removed by vacuum rotary evaporation to obtain azatetrafluorene ring tetracarboxylic acid in 75% yield.

[0035] (3) Add azira-tetrafluorene tetracarboxylic acid to 30 mL of dibutyl ether to prepare a azira-tetrafluorene tetracarboxylic acid dibutyl ether solution with a mass concentration of 45 % (w / v). Then add 30 mL of 15% (w / v) lanthanum chloride aqueous solution, mix and shake for 5 minutes, let stand to separate the layers, collect the organic phase, dry with 3 g of anhydrous calcium chloride for 0.5 hours, and then add ferrocene to make the mass concentration of ferrocene 5% to obtain azira-tetrafluorene tetracarboxylic acid rare earth combustion aid.

[0036] Application of rare earth combustion aids, such as azirmonofluorenecyclotetracarboxylic acid, in catalytic combustion.

[0037] The application site uses a YYL(W) type oil (gas) organic carrier boiler manufactured by Suzhou Zhongyong Environmental Protection Technology Co., Ltd., model: YYL(W)-3500Y(Q), rated calorific value: 300 kcal, rated steam pressure: 0.8 MPa, maximum operating temperature: 320℃.

[0038] The rare earth gas combustion aid, aza-tetrafluorene cyclotetracarboxylic acid obtained in this embodiment, was atomized in the boiler combustion zone after being sprayed by a sprayer (produced by Shandong Qingzhou Haili Machinery, type FZ-6). The spraying amount was 0.4 L of aza-tetrafluorene cyclotetracarboxylic acid rare earth gas combustion aid per cubic meter of gas.

[0039] Based on the average daily gas consumption, the combustion efficiency of the gas increases by 16% after injecting the rare earth gas combustion additive, azotetrafluorenecyclotetracarboxylic acid.

[0040] Example 3 A method for preparing a rare earth combustion aid containing aza-tetrafluorenecyclotetracarboxylic acid includes the following steps: (1) Under nitrogen protection, 3 g of 2,7-diaminofluorene and 0.5 g of sodium bicarbonate were added to 80 mL of xylene. The mixture was cooled to 8 °C, and 15 mL of dibromoethane was added dropwise over half an hour. The reaction mixture was then stirred at 60 °C for 6 hours. After the reaction was completed, the reaction mixture was poured into 12 times its volume of ice water and stirred for 8 minutes. The mixture was then filtered, and the precipitate was washed three times with water to obtain azatetrafluorene rings with a yield of 86%. (2) Under nitrogen protection, 2 g of azatetrafluorene ring was added to 70 mL of dimethyl sulfoxide, followed by 4 g of sodium methoxide, and then stirred at 35 °C for 90 minutes. Next, 0.1 mL of allyl chloride was added dropwise to the reaction mixture, and the reaction was continued with stirring for 5 hours. After the reaction was complete, 12 times the volume of distilled water was added to the reaction mixture, filtered, and the precipitate was transferred to 80 mL of dichloromethane. 2 g of sodium periodate, 3 g of potassium perchromate, and 1 mL of water were added. The reaction mixture was stirred at 30 °C for 18 hours. After the reaction was complete, the reaction mixture was washed twice with 80 mL of saturated sodium chloride aqueous solution. The organic layer was dried with 3 g of anhydrous Na₂SO₄ for 1 hour, filtered, and the solvent was removed using a vacuum rotary evaporator to obtain azatetrafluorene ring tetracarboxylic acid with a yield of 80%. (3) Add azira-tetrafluorene tetracarboxylic acid to 80 mL of dibutyl ether to prepare a 55% (w / v) dibutyl ether solution of azira-tetrafluorene tetracarboxylic acid. Then add 60 mL of 25% (w / v) europium chloride aqueous solution, mix and shake for 20 minutes, let stand to separate the layers, collect the organic phase, dry with 8 g of anhydrous calcium chloride for 1 hour, and then add 8% (w / v) ferrocene to obtain azira-tetrafluorene tetracarboxylic acid rare earth combustion aid.

[0041] Application of rare earth combustion aids, such as azirmonofluorenecyclotetracarboxylic acid, in catalytic combustion.

[0042] The application site features a horizontal vacuum hot water boiler manufactured by Taian Weiye Electromechanical Technology Co., Ltd., model ZKW2.1, with a rated calorific value of 2.1 MW and a rated steam pressure of 1.25 MPa.

[0043] The rare earth gas combustion aid, aza-tetrafluorene cyclotetracarboxylic acid obtained in this embodiment, was atomized in the boiler combustion zone after being sprayed by a sprayer (produced by Shandong Qingzhou Haili Machinery, type FZ-6). The spraying amount was 0.3 L of aza-tetrafluorene cyclotetracarboxylic acid rare earth gas combustion aid per cubic meter of gas.

[0044] Based on the average daily gas consumption, the combustion efficiency of the gas increases by 14% after injecting the rare earth gas combustion additive, azotetrafluorenecyclotetracarboxylic acid.

[0045] Comparative Example 1 A method for preparing a combustion improver based on a dibutyl ether solution of azatetrafluorenecyclotetracarboxylic acid includes the following steps: (1) Under nitrogen protection, 5 g of 2,7-diaminofluorene and 0.8 g of sodium bicarbonate were added to 100 mL of xylene. After cooling to 10 °C, 25 mL of dibromoethane was added dropwise over half an hour. The mixture was then stirred at 90 °C for 8 h. After the reaction was completed, the reaction mixture was poured into 15 times its volume of ice water and stirred for 10 minutes. The mixture was then filtered, and the precipitate was washed three times with water to obtain azatetrafluorene ring with a yield of 97.2%. (2) Under nitrogen protection, 3 g of azatetrafluorene ring was added to 100 mL of dimethyl sulfoxide, followed by 6 g of sodium methoxide, and then stirred at 40 °C for 120 min. Next, 0.15 mL of allyl chloride was added dropwise to the reaction mixture, and the reaction was continued with stirring for 6 h. After the reaction was complete, 20 times the volume of distilled water was added to the reaction mixture, filtered, and the precipitate was transferred to 100 mL of dichloromethane. 3 g of sodium periodate, 4 g of potassium perchromate, and 2 mL of water were added. The reaction was stirred at 35 °C for 18 h. After the reaction was complete, the reaction mixture was washed twice with 100 mL of saturated sodium chloride aqueous solution. The organic layer was dried with 4 g of anhydrous Na₂SO₄ for 1.5 h, filtered, and the solvent was removed using a vacuum rotary evaporator to obtain azatetrafluorene ring tetracarboxylic acid with a yield of 85%. (3) Add aziratenecyclotetracarboxylic acid to 100 mL of dibutyl ether to prepare a dibutyl ether solution with a mass concentration of 50% (w / v) of aziratenecyclotetracarboxylic acid.

[0046] The application site uses a vertical fully automatic oil (gas) steam boiler owned by 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, heating area: 7.32 m². 2 .

[0047] The dibutyl azirconium tetrafluorene cyclotetracarboxylate solution obtained in this embodiment was sprayed using a sprayer (manufactured by Shandong Qingzhou Haili Machinery, type FZ-6) to form an atomized layer in the boiler combustion zone. The spray volume was 0.7 L of dibutyl azirconium tetrafluorene cyclotetracarboxylate solution per cubic meter of fuel gas. Based on the average daily fuel consumption, the fuel gas combustion efficiency increased by 1.5% after spraying the rare earth fuel gas combustion aid.

[0048] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method for preparing a rare earth combustion aid containing aza-tetrafluorenecyclotetracarboxylic acid, characterized in that, Includes the following steps: (1) Under nitrogen protection, 2,7-diaminofluorene and sodium bicarbonate were added to xylene. After cooling to 4~10 ℃, dibromoethane was added dropwise. The reaction was stirred at 30~90 ℃ for 2~8 h. After the reaction was completed, the reaction mixture was poured into 10~15 times the volume of ice water and stirred for 5~10 min. The mixture was filtered and the precipitate was washed with water 3 times to obtain the azatetrafluorene ring. (2) Under nitrogen protection, the azatetrafluorene ring was added to dimethyl sulfoxide, and then sodium methoxide was added. After stirring the reaction at 25-40 °C for 30-120 min, allyl chloride was added dropwise to the reaction mixture and the reaction was continued. After the reaction was completed, distilled water was added to the reaction mixture, filtered, and the precipitate was transferred to dichloromethane. Sodium periodate, potassium perchromate and water were added. After the reaction was completed, the reaction product was washed twice with saturated sodium chloride aqueous solution. The organic layer was dried with anhydrous Na2SO4 for 0.5-1.5 h, filtered, and the solvent was removed on a vacuum rotary evaporator to obtain azatetrafluorene tetracarboxylic acid. (3) Add the azira-tetrafluorene cyclotetracarboxylic acid prepared in step (2) to an organic solvent to prepare an azira-tetrafluorene cyclotetracarboxylic acid solution, then add an aqueous solution of rare earth chloride, mix and shake for 5~30 min, let stand to separate into layers, collect the organic phase, dry with anhydrous calcium chloride for 0.5~1.5 h, and then add ferrocene to obtain azira-tetrafluorene cyclotetracarboxylic acid rare earth combustion aid.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass-to-volume ratio of 2,7-diaminofluorene to xylene is (0.5~5) g:(30~100) mL, the mass-to-volume ratio of sodium bicarbonate to xylene is (0.1~0.4) g:(15~50) mL, the volume ratio of dibromoethane to xylene is (2~25):(30~100), and the yield of the azatetrafluorene ring is 82~97.2%.

3. The preparation method according to claim 1, characterized in that, In step (2), the mass-to-volume ratio of the azatetrafluorene ring to dimethyl sulfoxide is (1.5~3) g:(30~100) mL, the mass-to-volume ratio of the sodium methoxide to dimethyl sulfoxide is (1~3) g:(15~50) mL, the volume ratio of the added allyl chloride to dimethyl sulfoxide is (0.02~0.15):(30~100), and after adding allyl chloride, the reaction continues for 3~6 h.

4. The preparation method according to claim 1, characterized in that, In step (2), the volume ratio of dichloromethane to dimethyl sulfoxide is 1:1, the mass-to-volume ratio of sodium periodate to dichloromethane is (1~3) g:(30~100) mL, the mass-to-volume ratio of potassium perchromate to dichloromethane is (0.5~4) g:(30~100) mL, and the volume ratio of water to dichloromethane is (1~2):(30~100). After adding sodium periodate, potassium perchromate, and water, the reaction is carried out at 25~35℃ for 16~18 h, and the yield of azatetrafluorene cyclotetracarboxylic acid is 75~85%.

5. The preparation method according to claim 1, characterized in that, In step (3), the organic solvent includes at least one of dibutyl ether, ethyl acetate, ethylene glycol dibutyl ether, and propyl acetate, and the mass concentration of the azirtetrafluorene tetracarboxylic acid solution is 45-55%.

6. The preparation method according to claim 1, characterized in that, In step (3), the rare earth chloride includes any one of lanthanum chloride, cerium chloride, and europium chloride, the mass concentration of the rare earth chloride in the aqueous solution of the rare earth chloride is 15-25%, and the volume ratio of the rare earth chloride aqueous solution to the organic solvent is 1:

1.

7. The preparation method according to claim 1, characterized in that, In step (3), after adding ferrocene, the mass concentration of ferrocene is 5~10%.

8. The aza-tetrafluorenecyclotetracarboxylic acid rare earth combustion aid prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the aza-tetrafluorenecyclotetracarboxylic acid rare earth combustion aid as described in claim 8 in catalytic combustion.

10. The application according to claim 9, characterized in that, The application involves atomizing the rare earth gas combustion aid, azirtetrafluorene cyclotetracarboxylate, in the boiler combustion zone after being sprayed by a sprayer, with an injection volume of 0.1-0.5 liters of azirtetrafluorene cyclotetracarboxylate rare earth gas combustion aid per cubic meter of gas.

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