Device and process for reducing pollution, storing hydrogen and preparing ammonia by using redundant electric energy

Abstract

The device comprises a reactor a and a reactor b, the reactor a sequentially comprises a hydrogen peroxide oxidation system I, an ammonia production system II and a nitrogen fixation system III from top to bottom, the structure of the steel reactor b is the same as that of the reactor a, and the tops of the reactor a and the reactor b are connected with a four-way valve A; the bottoms of the reactor a and the reactor b are connected with a four-way valve B, and hydrogen peroxide spraying devices are respectively arranged in the reactor a and the reactor b. The whole reaction process comprises a nitrogen fixation process and an ammonia preparation process, and two reaction devices with the same structure are connected through a four-way valve to realize circular reaction, so that NO is continuously consumed, NH3 is generated, and the dual targets of pollution reduction and energy conversion are realized. According to the invention, NO conversion and NH3 synthesis are carried out by using redundant electric energy, so that the utilization efficiency of the electric energy is improved, dependence on fossil fuel is reduced, and sustainable utilization of energy is realized.

Description

Technical Field

[0001] The present invention belongs to the field of energy manufacturing, and in particular relates to a device and process for utilizing redundant electric energy to reduce pollution, store hydrogen and produce ammonia. Background Art

[0002] China is a major coal producer and consumer in the world, with coal dominating its energy structure. Although China is reducing its reliance on coal, it is expected to remain the main energy source by 2035. Coal use leads to high NOx emissions, and controlling NOx emissions is an important task for China's environmental protection. In the field of renewable energy, the instability of power supply often occurs due to the intermittent nature of power generation and transmission limitations. Hydrogen energy storage technology has emerged as the times require. It converts electricity into hydrogen energy and uses excess, off-peak or low-quality electricity to produce hydrogen on a large scale through the mutual conversion of electricity and hydrogen energy, converting electrical energy into hydrogen energy for storage. When the power supply is insufficient, power generation can be supplemented by hydrogen fuel cells or other chemical reactions. Hydrogen fuel cells can directly convert the chemical energy of hydrogen into electrical energy, avoiding energy loss in the intermediate conversion process, achieving high-efficiency power generation, and being more environmentally friendly and practical.

[0003] In addition, ammonia production and hydrogen storage technology also shows significant advantages. Ammonia has a high energy density, and its volume energy density is about 13.6MJ·L -1 , which means that the energy contained in 1 liter of liquid ammonia is equivalent to 4.5 liters of high-pressure hydrogen (35.0MPa) or 1,200 liters of hydrogen at room temperature and pressure. The liquefaction, storage and transportation costs of ammonia are relatively low, and it can be liquefied at a pressure of only 1.0MPa, which is much lower than the storage and transportation costs of liquid hydrogen. In terms of safety, ammonia has a narrow range of explosion limits and a high boiling point, which reduces the risk of fire and explosion. The pungent smell of ammonia also makes leaks easier to detect. Finally, ammonia is easy to liquefy and store, and can be liquefied with just a slight pressurization at -10°C, with little energy loss, high safety, and easy storage and transportation. These characteristics make ammonia a highly potential medium for hydrogen storage and transportation. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a device and process for utilizing redundant electric energy to reduce pollution, store hydrogen and produce ammonia. The present invention first utilizes hydride silicon aluminum molecular sieve to catalyze hydrogen peroxide (H2O2) to effectively oxidize NO, and combines it with an alkaline absorbent to achieve effective storage of nitrates, while utilizing a Cu / Ce catalyst to promote the synthesis of ammonia (NH3). The use of redundant electric energy to reduce pollution, store hydrogen and produce ammonia is achieved through a catalyst process combination process, providing an innovative process and method that can both efficiently remove pollutants and efficiently produce ammonia.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A device for reducing pollution by storing hydrogen and producing ammonia using redundant electric energy comprises a reactor a and a reactor b. The reactor a comprises a hydrogen peroxide oxidation system I, an ammonia production system II and a nitrogen fixation system III from top to bottom. The structure of the reactor b is the same as that of the reactor a. The tops of the reactors a and b are connected with a four-way valve A, and the bottoms of the reactors a and b are connected with a four-way valve B. The reactors a and b are respectively provided with hydrogen peroxide spraying devices and are located above the hydrogen peroxide oxidation system I.

[0007] Furthermore, the reactor a and the reactor b are steel reactors, and are provided with heating jackets on the outside to achieve segmented heating.

[0008] Furthermore, the catalyst type used in hydrogen peroxide oxidation system I is hydrogenated silicon aluminum molecular sieve, the molecular sieve is a medium-pore or macroporous structure, the pore size is greater than 50nm, and the catalyst Si / Al is 5-30. Ammonium chloride, ammonium nitrate, ammonium carbonate and other reagents are used for hydrogenation treatment of silicon aluminum molecular sieve, and the catalyst calcination temperature is 500-600℃.

[0009] Furthermore, the catalyst type used in the ammonia production system II is a Cu / Ce catalyst, the copper precursors are copper nitrate, copper chloride, and copper sulfate, the Cu loading is 1-10wt%, and the carrier type is CeO2.

[0010] Furthermore, the nitrogen fixation system III uses a supported alkaline absorbent, wherein the alkaline components of the supported alkaline absorbent are alkali metal oxides and alkaline earth metal oxides, and the carrier is a single γ-Al2O3, SiO2 or TiO2.

[0011] The present invention also provides a process for producing ammonia by storing hydrogen for pollution reduction using the device, comprising the following steps:

[0012] (1) First, connect the valve port 1 of the four-way valve A to the valve port 2, and the valve port 3 to the valve port 4; connect the valve port 5 of the four-way valve B to the valve port 8, and the valve port 6 to the valve port 7; then simultaneously carry out the following (2) and (3);

[0013] (2) Nitrogen fixation process: Flue gas containing a large amount of NO is introduced into reactor a through valve port 1, and H2O2 solution is injected into hydrogen peroxide oxidation system I through a spray device. Flue gas first passes through hydrogen peroxide oxidation system I, and uses hydrogenated silicon aluminum molecular sieve to catalyze H2O2 to oxidize nitrogen monoxide in flue gas to generate water-soluble high-valent nitrogen oxides, nitrous acid and nitric acid. After heating, the flue gas is finally introduced into ammonia production system II in gaseous form, namely, gaseous nitrogen oxides, gaseous nitrous acid and gaseous nitric acid. In ammonia production system II, no chemical reaction occurs, and the gas enters nitrogen fixation system III. In nitrogen fixation system III, gaseous nitrogen oxides, gaseous nitrous acid and gaseous nitric acid react with alkali metal oxides in alkaline absorbent to generate nitrates and store them. Clean gas is discharged from the tail of valve port 7, completing the nitrogen fixation process.

[0014] (3) Ammonia production process: Reactor b has completed the nitrogen fixation process in advance. At this time, a mixed gas containing hydrogen and water vapor enters reactor b through valve port 5. The mixed gas first enters nitrogen fixation system III, where water vapor and stored nitrate are hydrolyzed to produce nitric acid vapor and generate alkali metal oxides. Subsequently, hydrogen and the generated nitric acid vapor enter ammonia production system II together; in the ammonia production system II, hydrogen and nitric acid vapor react on the catalyst surface to produce ammonia, which is discharged from valve port 3 through hydrogen peroxide oxidation system I.

[0015] Furthermore, during the nitrogen fixation process in step (2), the NO concentration in the flue gas is 100-20000 ppm, and the flue gas volume is 1000-500000 m 3 / min, volume space velocity is 2000-200000h -1 , the molar ratio of H2O2 and NO is (0.1-5):1, and the concentration of H2O2 solution is 1-5mol / L.

[0016] During the nitrogen fixation process in step (2), the temperature of the reaction chamber of the hydrogen peroxide oxidation system I is 100-250°C.

[0017] In the ammonia production process of step (3), the volume concentration of H2 in the mixed gas containing hydrogen and water vapor is 1%-10%, the volume concentration of water vapor is 1%-5%, and the rest is N2. The gas volume of the mixed gas is 100-500000m 3 / min, volume space velocity is 2000-200000h -1 .

[0018] Furthermore, in the ammonia production process of step (3), the reaction temperature of the nitrogen fixation system III is 100-300°C.

[0019] Furthermore, during the ammonia production process in step (3), the reaction temperature of the ammonia production system II is 150-250°C.

[0020] It should be noted that redundant electric energy is used to heat reactor a and reactor b, and the H2 introduced in the ammonia production process in step (3) is produced by electrolyzing water using redundant electric energy. Since reactor a and reactor b can be heated in stages, it is not necessary to heat ammonia production system II in the nitrogen fixation process in step (2), and it is not necessary to heat hydrogen peroxide oxidation system I in the ammonia production process in step (3).

[0021] Compared with the prior art, the device and process of the present invention have the following beneficial effects:

[0022] 1. The entire reaction process connects two reaction devices of the same structure through a four-way valve to achieve a cyclic reaction, thereby continuously consuming NO and producing NH3, achieving the dual goals of pollution reduction and energy conversion.

[0023] 2. Using redundant electric energy to convert NO and synthesize NH3 improves the efficiency of electric energy utilization, reduces dependence on fossil fuels, and helps achieve sustainable use of energy.

[0024] 3. The process can be adjusted according to the actual situation of power supply and NO emissions, with good flexibility and adaptability, suitable for different industrial environments and energy management needs.

[0025] 4. The catalysis of H2O2 by hydridosilicon aluminum molecular sieve and Cu / Ce catalyst improved the NO conversion rate and NH3 synthesis efficiency, demonstrating the innovative technology application in the field of chemical engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the structure of a hydrogen storage and ammonia production device that utilizes redundant electric energy to reduce pollution.

[0028] Figure 2 Schematic diagram of the cyclic reaction process of the hydrogen storage and ammonia production process using redundant electricity to reduce pollution.

[0029] Figure 3 The efficiency of NO oxidation by H-SM-5 at different hydrogen peroxide concentrations. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention, and those skilled in the art in this field can make some non-essential improvements and adjustments based on the content of the above invention.

[0031] Example 1

[0032] Figure 1 This is a schematic diagram of the structure of a hydrogen storage and ammonia production device that uses redundant electric energy to reduce pollution. The device consists of two steel reactors with the same structure and function, marked as a and b, which are connected to each other through a four-way valve to achieve a cyclic reaction. This design allows two processes - nitrogen fixation and ammonia production to be carried out simultaneously. The specific structure is as follows:

[0033] A device for reducing pollution by storing hydrogen and producing ammonia using redundant electric energy, comprising a reactor a and a reactor b, wherein the reactor a comprises a hydrogen peroxide oxidation system I, an ammonia production system II and a nitrogen fixation system III from top to bottom, and the structure of the reactor b is the same as that of the reactor a, and the tops of the reactors a and b are connected with a four-way valve A, and the bottoms of the reactors a and b are connected with a four-way valve B, and the reactors a and b are respectively provided with hydrogen peroxide spraying devices. Preferably, the reactors a and b are steel reactors, and are provided with heating jackets on the outside to achieve segmented heating.

[0034] The catalyst type used in the hydrogen peroxide oxidation system I is hydrogenated silicon aluminum molecular sieve, the molecular sieve is a mesoporous or macroporous structure, the pore size is greater than 50nm, and the catalyst Si / Al is 5-30. Ammonium chloride, ammonium nitrate, ammonium carbonate and other reagents are used for hydrogenation of silicon aluminum molecular sieve, and the catalyst calcination temperature is 500-600°C. The catalyst type used in the ammonia production system II is a Cu / Ce catalyst, the copper precursor is copper nitrate, copper chloride, copper sulfate, the Cu loading is 1-10wt%, and the carrier type is CeO2. The nitrogen fixation system III uses an alkali absorbent, the alkaline components of the alkali absorbent are K, Na, Ca, and the carrier type is γ-Al2O3, SiO2 or TiO2.

[0035] Example 2

[0036] The process of reducing pollution and storing hydrogen to produce ammonia using the device described in Example 1 is as follows:

[0037] (1) First, connect the valve port 1 of the four-way valve A to the valve port 2, and the valve port 3 to the valve port 4; connect the valve port 5 of the four-way valve B to the valve port 8, and the valve port 6 to the valve port 7; then simultaneously carry out the following (2) and (3);

[0038] (2) Nitrogen fixation process: gas volume is 1000m 3 / min, volume air velocity is 12000h -1 , the flue gas containing 2000ppm NO is introduced into the steel reactor a through valve port 1, and the flue gas is firstly passed through the hydrogen peroxide oxidation system I, the molar ratio of H2O2 and NO is 1:1, the concentration of H2O2 solution is 4mol / L, the temperature of the reaction chamber is 200℃, and the hydrogen peroxide is catalyzed by the hydrogenated silicon aluminum molecular sieve H-ZSM-5 to oxidize the nitric oxide in the flue gas to generate water-soluble high-valent nitrogen oxides, nitrous acid and nitric acid, which are finally heated and introduced into the ammonia production system II in the form of gaseous nitrogen oxides, gaseous nitrous acid and gaseous nitric acid;

[0039] In the ammonia production system II, no chemical reaction occurs, and the gas enters the nitrogen fixation system III;

[0040] In nitrogen fixation system III, gaseous nitrogen oxides, gaseous nitrous acid and gaseous nitric acid react with alkali metal oxides in alkaline absorbent K2O / γ-Al2O3 to generate nitrates which are stored, and clean gas is discharged from the tail of valve 7 to complete the nitrogen fixation process.

[0041] (3) Ammonia production process: A mixed gas containing hydrogen and water vapor is introduced into reactor b through valve port 5 (reactor b has previously completed the nitrogen fixation process, as in step (2) above). The mixed gas (hydrogen volume concentration is 10% and water vapor volume concentration is 3%, and the rest is nitrogen) is heated to 1000 m 3 / min, volume air velocity 6000h -1 First, it enters the nitrogen fixation system III, where water vapor reacts with the stored nitrate at 250°C to produce nitric acid vapor and generate alkali metal oxides. Subsequently, hydrogen and the produced nitric acid vapor enter the ammonia production system II together;

[0043] In the ammonia production system II, under normal pressure conditions, hydrogen with a volume concentration of 10% reacts with nitric acid vapor at 200°C under the catalytic action of Cu / Ce catalyst to generate ammonia, which is discharged through the hydrogen peroxide oxidation system I and valve port 3, thus completing the ammonia production process.

[0044] The above steps (2) and (3) are performed simultaneously. After completion, the valve port 1 of the four-way valve A is connected to the valve port 4, the valve port 2 is connected to the valve port 3, the valve port 5 of the four-way valve B is connected to the valve port 6, and the valve port 7 is connected to the valve port 8. According to the operations of the above steps (2) and (3), the nitrogen fixation process of step (2) is carried out in the reactor b, and the ammonia production process of step (3) is carried out in the reactor a simultaneously, so that the cyclic reaction (such as Figure 2 shown).

[0045] The laboratory preparation process of the hydrogenated silicon aluminum molecular sieve H-ZSM-5 includes the following steps:

[0046] Using 30 ml of 1.0 mol / L NH4Cl aqueous solution, ion exchange was performed at 60°C for 2 h (repeated three times), the sample was filtered, washed with distilled water, the sediment was dried at 110°C for 12 h, and then calcined at 600°C for 1 h to obtain H-ZSM-5. Its efficiency in oxidizing NO with H2O2 solution is as follows: Figure 3 shown.

[0047] The laboratory preparation process of the alkaline absorbent K2O / γ-Al2O3 includes the following steps:

[0048] 1g of the finished γ-Al2O3 carrier was calcined at 550℃ for 2 hours, then 5g of KNO3 was accurately weighed and dissolved in 30ml of deionized water to prepare an impregnation solution of the required concentration. K was loaded on the γ-Al2O3 carrier by wet impregnation. After drying at 80℃ and calcining at a certain temperature of 550℃, the obtained catalysts were named K2O / γ-Al2O3.

[0049] The laboratory preparation process of the Cu / Ce catalyst includes the following steps:

[0050] Dissolve 10g of Ce(NO3)3·6H2O in 30ml of deionized water and stir until completely dissolved. Then add 30ml of concentrated ammonia water and stir the precipitate. After aging for 3 hours at room temperature, wash the precipitate several times with deionized water to pH = 7. Finally, dry the precipitate at 80°C for 10 hours) and then calcine it at 550°C in a muffle furnace for 2 hours. It is labeled as CeO2-OH. Using the wet impregnation method, weigh 0.78g of copper nitrate solution as a precursor to load Cu on the CeO2 carrier. After drying at 80°C and calcining at 550°C, the resulting catalysts were named Cu / Ce.

[0051] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A device for reducing pollution by storing hydrogen and producing ammonia using redundant electric energy, characterized in that: The invention comprises a reactor a and a reactor b. The reactor a comprises a hydrogen peroxide oxidation system I, an ammonia production system II and a nitrogen fixation system III from top to bottom. The structure of the steel reactor b is the same as that of the reactor a. The tops of the reactor a and the reactor b are connected with a four-way valve A, the bottoms of the reactor a and the reactor b are connected with a four-way valve B, and the reactor a and the reactor b are respectively provided with a hydrogen peroxide spraying device.

2. The device for reducing pollution by storing hydrogen and producing ammonia using redundant electric energy according to claim 1, characterized in that: The catalyst type used in hydrogen peroxide oxidation system I is hydride silicon aluminum molecular sieve, the molecular sieve has a medium or large pore structure, the pore size is greater than 50nm, and the catalyst Si / Al is 5-30.

3. The device for reducing pollution by storing hydrogen and producing ammonia using redundant electric energy according to claim 1, characterized in that: The catalyst type used in the ammonia production system II is a Cu / Ce catalyst, the copper precursors are copper nitrate, copper chloride, and copper sulfate, the Cu loading is 1-10wt%, and the carrier is CeO2.

4. The device for reducing pollution by storing hydrogen and producing ammonia using redundant electric energy according to claim 1, characterized in that: Nitrogen fixation system III uses a supported alkaline absorbent, in which the alkaline components are alkali metal oxides and alkaline earth metal oxides, and the carrier is a single γ-Al2O3, SiO2 or TiO2.

5. A process for producing ammonia by storing hydrogen with pollution reduction using the device described in any one of claims 1 to 4, characterized in that: The following steps are involved: (1) First, connect the valve port 1 of the four-way valve A to the valve port 2, and the valve port 3 to the valve port 4; connect the valve port 5 of the four-way valve B to the valve port 8, and the valve port 6 to the valve port 7; then simultaneously carry out the following (2) and (3); (2) Nitrogen fixation process: Flue gas containing a large amount of NO is introduced into reactor a through valve port 1, and H2O2 solution is injected into hydrogen peroxide oxidation system I through a spray device. Flue gas first passes through hydrogen peroxide oxidation system I, and uses hydrogenated silicon aluminum molecular sieve to catalyze H2O2 to oxidize nitrogen monoxide in flue gas to generate water-soluble high-valent nitrogen oxides, nitrous acid and nitric acid. After heating, the flue gas is finally introduced into ammonia production system II in gaseous form, namely, gaseous nitrogen oxides, gaseous nitrous acid and gaseous nitric acid. In ammonia production system II, no chemical reaction occurs, and the gas enters nitrogen fixation system III. In nitrogen fixation system III, gaseous nitrogen oxides, gaseous nitrous acid and gaseous nitric acid react with alkali metal oxides in alkaline absorbent to generate nitrates and store them. Clean gas is discharged from the tail of valve port 7, completing the nitrogen fixation process. (3) Ammonia production process: Reactor b has completed the nitrogen fixation process in advance. At this time, a mixed gas containing hydrogen and water vapor enters reactor b through valve port 5. The mixed gas first enters nitrogen fixation system III, where water vapor and stored nitrate are hydrolyzed to produce nitric acid vapor and generate alkali metal oxides. Subsequently, hydrogen and the generated nitric acid vapor enter ammonia production system II together; in the ammonia production system II, hydrogen and nitric acid vapor react on the catalyst surface to produce ammonia, which is discharged from valve port 3 through hydrogen peroxide oxidation system I.

6. The process according to claim 5, characterized in that During the nitrogen fixation process in step (2), the NO concentration in the flue gas is 100-20000 ppm, and the flue gas volume is 1000-500000 m 3 / min, volume space velocity is 2000-200000h -1 , the molar ratio of H2O2 and NO is (0.1-5):1, and the concentration of H2O2 solution is 1-5mol / L.

7. The process according to claim 5, characterized in that During the nitrogen fixation process in step (2), the temperature of the reaction chamber of the hydrogen peroxide oxidation system I is 100-250°C.

8. The process according to claim 5, characterized in that In the ammonia production process of step (3), the volume concentration of H2 in the mixed gas containing hydrogen and water vapor is 1%-10%, the volume concentration of water vapor is 1%-5%, and the rest is N2. The gas volume of the mixed gas is 100-500000m 3 / min, volume space velocity is 2000-200000h -1 .

9. The process according to claim 5, characterized in that During the ammonia production process in step (3), the reaction temperature of the nitrogen fixation system III is 100-300°C.

10. The process according to claim 5, characterized in that During the ammonia production process in step (3), the reaction temperature of the ammonia production system II is 150-250°C.

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