Flue gas micro-nano bubble-based solid fuel comprehensive modification device and electric power system

Abstract

The invention belongs to the field of solid fuel modification, and particularly discloses a solid fuel comprehensive modification device based on flue gas micro-nano bubbles and an electric power system.The solid fuel comprehensive modification device comprises a modification unit, the modification unit comprises at least one water washing assembly, and each water washing assembly comprises at least one water washing box; the water washing tank is used for containing solid fuel to be modified and introducing a liquid solvent to form mixed slurry, and non-desulfurized flue gas is introduced into the mixed slurry in the form of micro-nano bubbles to achieve comprehensive modification of the solid fuel. On one hand, mineral substances such as alkali metal and alkaline earth metal in the solid fuel can be removed, so that the heat value of the solid fuel is effectively increased, the contamination and slagging tendency in the combustion process is weakened, the emission amount of particulate matter is reduced, and on the other hand, the physical characteristics and chemical characteristics of the solid fuel can be improved; such as a carbon structure, a pore structure, hydrophilicity and hydrophobicity, free radicals and the like, so that subsequent high-value utilization of the solid fuel is facilitated, and comprehensive modification of the solid fuel is realized.

Description

Technical Field

[0001] The present application belongs to the field of solid fuel modification, and more specifically, to a solid fuel comprehensive modification device and power system based on flue gas micro-nano bubbles. Background Art

[0002] Solid fuel modification is a technical means to improve the combustion performance and energy efficiency of solid fuels by changing their chemical structure and physical properties. In the prior art, solid fuels are mainly modified by physical, chemical or biological methods, but they have single functions and can only meet specific industrial needs, and cannot achieve comprehensive modification and quality improvement of solid fuels. At the same time, the modification effect of existing solid fuel modification devices is poor. In order to improve the modification effect, it is usually necessary to add additional chemical reagents or complicate the design of the device structure, which has the problems of high cost and difficulty in industrial application. Summary of the invention

[0003] In response to the defects of the prior art, the present application provides a comprehensive solid fuel modification device and power system based on flue gas micro-nano bubbles, aiming to solve the problems of existing modification devices having single functions, poor modification effects, and being unable to achieve comprehensive modification.

[0004] According to one aspect of the present application, a solid fuel comprehensive modification device based on flue gas micro-nano bubbles is provided, the solid fuel comprehensive modification device comprising a modification unit, the modification unit comprising at least one group of water washing components, each group of the water washing components comprising at least one water washing box, the water washing box being used to hold the solid fuel to be modified, the water washing box being provided with a water inlet, an air inlet, an air outlet and a slurry outlet, the water inlet being used to introduce a liquid solvent to form a mixed slurry; the air inlet being used to introduce undesulfurized flue gas, and the air inlet being provided with a micro-nano bubble generator, for introducing the undesulfurized flue gas into the mixed slurry in the form of micro-nano bubbles, so that under the joint action of the multi-free radicals generated by the micro-nano bubbles and the complex flue gas components, the solid fuel is demineralized and the physical and chemical properties of the solid fuel are improved; the air outlet is used to discharge the flue gas after the modification reaction; the slurry outlet is used to discharge the modified mixed slurry, thereby realizing comprehensive modification of the solid fuel.

[0005] Through the above technical scheme conceived by the present application, compared with the prior art, since the present application introduces micro-nano bubbles into the solid fuel modification, it can achieve physical and chemical modifications while carrying out demineralization treatment in combination with undesulfurized flue gas, thereby achieving comprehensive modification of solid fuel.

[0006] As a further preferred embodiment, the comprehensive solid fuel modification device also includes a slurry conveying unit and a slurry processing unit. The slurry conveying unit is arranged between the modification unit and the slurry processing unit, and is used to convey the modified mixed slurry into the slurry processing unit; the slurry processing unit is used to perform solid-liquid separation and drying treatment on the modified mixed slurry to obtain modified solid fuel.

[0007] As a further preference, the slurry processing unit includes a solid-liquid separation component and a drying component, one end of the solid-liquid separation component is connected to the slurry conveying unit, and the other end is connected to the drying component, for performing solid-liquid separation on the modified mixed slurry and sending the separated solid matter to the drying component for drying, thereby obtaining modified solid fuel.

[0008] As further preferred, each group of water washing components in the modification unit is connected in parallel, and each water washing tank in the water washing component is connected in parallel.

[0009] As further preferred, the air inlet is used to be connected to the outlet of the dust collector so as to pass the undesulfurized flue gas into the modification unit.

[0010] According to another aspect of the present application, there is provided an electric power system including the above-mentioned solid fuel comprehensive modification device, the electric power system also including a boiler, a dust collector, a desulfurization tower and a flue gas heat exchanger connected in sequence along the flue gas flow direction, the air inlet of the modification unit is connected to the outlet of the dust collector to feed the undesulfurized flue gas into the modification unit; the air outlet of the modification unit is respectively connected to the inlet of the desulfurization tower and the inlet of the flue gas heat exchanger to feed the flue gas after the modification reaction into the desulfurization tower or the flue gas heat exchanger.

[0011] As a further preference, the drying component is connected to the outlet of the boiler to utilize the flue gas for heat exchange drying.

[0012] As a further preference, the outlet of the dust collector is respectively connected to the inlet of the desulfurization tower and the air inlet of the modification unit through a first control valve, so as to adjust the proportion of flue gas entering the modification unit according to the operating condition of the modification unit; the air outlet of the modification unit is respectively connected to the inlet of the desulfurization tower and the inlet of the flue gas heat exchanger through a second control valve, so as to control the flue gas after the modification reaction to enter the desulfurization tower or the flue gas heat exchanger according to the operating condition of the modification unit.

[0013] As further preferred, the modification unit further includes a SO2 concentration detection component, which is disposed between the gas outlet and the second control valve to control the flue gas entering the desulfurization tower or the flue gas heat exchanger according to the SO2 concentration in the flue gas after the modification reaction.

[0014] As further preferred, the power system further includes a control device, which is connected to the first control valve and the second control valve of the modification unit for performing flue gas distribution.

[0015] In general, the above technical solutions conceived by this application have the following technical advantages compared with the prior art:

[0016] 1. The present application sets micro-nano bubbles in the modification unit and passes the undesulfurized flue gas into the mixed slurry containing solid fuel in the form of micro-nano bubbles. The combined effect of sulfur-containing flue gas and micro-nano bubbles can be utilized to remove minerals such as alkali metals and alkaline earth metals in the solid fuel, thereby effectively improving the calorific value of the solid fuel, reducing the tendency of contamination and slagging during the combustion process, and reducing the emission of particulate matter. On the other hand, the physical and chemical characteristics of the solid fuel can be improved, such as carbon structure, pore structure, hydrophilicity, free radicals, etc., which is conducive to the subsequent high-value utilization of the solid fuel, thereby realizing the comprehensive modification of the solid fuel. The solid fuel has the advantages of simple operation, mild conditions, and low cost, and has a relatively broad application prospect.

[0017] 2. At the same time, the present application only needs to connect the air inlet of the modification unit to the dust collector, and connect the air outlet of the modification unit to the desulfurization tower and the flue gas heat exchanger, so that the solid fuel comprehensive modification device can be applied to the existing power system. Not only is the change to the existing power system minor, it can effectively reduce the cost of industrial application, and it can partially or completely replace the role of the desulfurization tower, realize the flue gas desulfurization while realizing the comprehensive modification of solid fuel, and further reduce the production cost;

[0018] 3. In addition, the present application can realize intelligent distribution of flue gas through the cooperation of the first control valve, the second control valve and the SO2 concentration detection component, thereby maximizing the flue gas desulfurization effect of the modification unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of a solid fuel comprehensive modification device provided in an embodiment of the present application;

[0020] Figure 2 It is a structural schematic diagram of a modification unit in a solid fuel comprehensive modification device provided in an embodiment of the present application;

[0021] Figure 3 is a schematic diagram of a power system including a solid fuel comprehensive modification device provided in an embodiment of the present application;

[0022] Figure 4 The removal rate of minerals in the modified coal obtained in Example 1 and Comparative Examples 1 to 3 of the present application;

[0023] Figure 5The total content of acid infusible minerals in the modified coal obtained in Example 1 and Comparative Examples 1 to 3 of the present application;

[0024] Figure 6 are the microcrystalline structure parameters of the modified coal obtained in Example 1 and Comparative Examples 1 to 3 of the present application, wherein (a) is d002, (b) is La, (c) is Lc, and (d) is fa;

[0025] Figure 7 The carbon structure parameter changes of the modified coal obtained in Example 1 and Comparative Examples 1 to 3 of the present application;

[0026] Figure 8 The S / N morphological distribution characteristics in the modified coal are obtained in Example 1 and Comparative Examples 1 to 3 of the present application, wherein (a) is the morphological distribution characteristics of the S element in the modified coal, and (b) is the morphological distribution characteristics of the N element in the modified coal.

[0027] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0028] 1-modification unit, 11-water washing box, 12-micro-nano bubble generator, 13-air inlet, 14-air outlet, 15-water inlet, 16-slurry outlet, 17-SO2 concentration detection component, 18-branch gas line, 19-main gas line, 2-slurry conveying unit, 21-slurry conveying pipeline, 22-screw propeller, 3-slurry processing unit, 31-solid-liquid separation component, 32-drying component, 4-boiler, 5-economizer, 6-dust collector, 7-desulfurization tower, 71-first control valve, 72-second control valve, 73-third control valve, 74-fourth control valve, 8-flue gas heat exchanger, 9-chimney. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0030] like Figure 1 , 2As shown, according to one aspect of the present application, a solid fuel comprehensive modification device based on flue gas micro-nano bubbles is provided, and the solid fuel comprehensive modification device includes a modification unit 1, wherein: the modification unit 1 includes at least one group of water washing components, each group of water washing components includes at least one water washing box 11, the water washing box 11 is used to hold the solid fuel to be modified and provide a reaction place for its comprehensive modification, the water washing box 11 is provided with a water inlet 15, an air inlet 13, an air outlet 14 and a slurry outlet 16, the water inlet 15 is used to pass a liquid solvent into the water washing box 11 to form Mixed slurry; the air inlet 13 is used to introduce undesulfurized flue gas into the water washing box 11, and the air inlet 13 is provided with a micro-nano bubble generator 12, which is used to introduce the undesulfurized flue gas into the mixed slurry in the form of micro-nano bubbles, so that under the joint action of multiple free radicals generated by the micro-nano bubbles and complex flue gas components, the solid fuel is demineralized and the physical and chemical properties of the solid fuel are improved; the air outlet 14 is used to discharge the flue gas after the modification reaction; the slurry outlet 16 is used to discharge the modified mixed slurry, so as to achieve comprehensive modification of the solid fuel.

[0031] This application introduces micro-nano bubbles into the modification of solid fuels, and cooperates with undesulfurized flue gas to achieve physical and chemical modification while performing demineralization treatment, thereby achieving comprehensive modification of solid fuels, effectively solving the problem of single function and poor effect of modification methods in the prior art. At the same time, this application uses the flue gas of the power plant itself to modify and pre-treat the solid fuel, which is not only simple in process and low in cost, but also can synergistically remove SO2 from the flue gas, effectively improve the overall removal efficiency of SO2 in the flue gas, and further reduce the operating cost of the power plant.

[0032] In terms of demineralization, the present application has a high demineralization efficiency, can effectively improve the calorific value of solid fuels, and at the same time reduce the tendency of contamination and slagging during combustion, and reduce the emission of particulate matter. During the modification process, the solubility of acidic gases in flue gas in water can be enhanced by generating flue gas micro-nano bubbles, significantly reducing the pH of the mixed slurry, and effectively removing alkali metals and alkaline earth metals (AAEMs) in the form of ion exchange and acid soluble in solid fuels. At the same time, due to the presence of flue gas micro-nano bubbles, more OH radicals, O radicals, etc. will be produced. Compared with the free H radicals that can only be provided by the acid solution in the pickling modification, the free radicals have stronger electronic energy, which can destroy the Al-O bond in the AAEMs aluminosilicate / silicate lattice structure to obtain Si-O bonds, thereby promoting the acid-insoluble AAEMs to transform into other forms, and improving the removal efficiency of AAEMs as a whole. The present application can also simultaneously remove some trace elements in solid fuels, reduce the enrichment of toxic elements in solid fuels, and reduce the toxicity of particulate matter. In addition, the present application utilizes the reaction of flue gas acid gases (SO2, CO2, HCl, etc.) with water in the form of micro-nano bubbles, and the formed mixed acidic solutions of H2SO3, H2SO4, H2CO3, HCl, etc., to achieve enhanced and efficient removal of inorganic impurities in solid fuels.

[0033] In terms of physical modification, this application can achieve the following effects:

[0034] (1) Changing the carbon structure: Flue gas micro-nano bubbles will produce strong oxidizing free radicals such as ·OH and ·O in water. These free radicals can effectively destroy the complex organic structure in the solid fuel, destroy the aromatic ring structure in the solid fuel, and reduce the aromatization degree of the solid fuel, thereby improving the thermal utilization (pyrolysis, combustion, gasification, etc.) efficiency of the solid fuel. They can also promote the breakage of the branch and bridge chains in the solid fuel and reduce the molecular weight of the solid fuel, thereby improving the liquefaction efficiency of the solid fuel.

[0035] (2) Pore change: Since strong oxidizing free radicals such as ·OH and ·O can destroy the complex organic structure in the solid fuel, reduce the degree of aromatization and molecular weight, and more effectively open the pores inside the solid fuel to form a pore-rich structure, it can also simultaneously increase the specific surface area of ​​the solid fuel particles, further improving the thermal utilization efficiency of the solid fuel. At the same time, if the solid fuel is subsequently processed into activated carbon, the larger specific surface area and pore structure can effectively increase the adsorption capacity of the activated carbon.

[0036] (3) Hydrophilicity and hydrophobicity: During the continuous generation of flue gas micro-nano bubbles, more ·OH free radicals will be generated. During the reaction with solid fuel, the ·OH free radicals will increase the -OH functional groups in the solid fuel particles, thereby increasing the hydrophilicity of the solid fuel and helping to improve the dispersibility and stability of the solid fuel in water. For the preparation of water-coal slurry, the increase in hydrophilicity can reduce the aggregation between coal particles and improve the fluidity of water-coal slurry, thereby improving its overall performance. At the same time, the increase in the hydrophilicity of coal will also increase the viscosity of coal, so that it can become a high-viscosity coal to replace coking coal.

[0037] If it is necessary to change the hydrophilicity or hydrophobicity of coal, the flue gas micro-nano bubble generating device can be subsequently turned off, and only flue gas components can be continuously introduced into the water. The H free radicals and water molecules generated by the O2, SO2 and other gases in the flue gas components dissolving in water can react with the functional groups on the surface of the solid fuel, thereby reducing the content of the -OH functional group and reducing the hydrophilicity of the solid fuel. The -OH functional groups will be partially replaced to generate linear or branched alkyl hydrocarbons, alkyl phenols and other hydrophobic groups, and even the solid fuel will become a hydrophobic solid fuel.

[0038] In terms of chemical modification, sulfur-containing molecular structures such as thiophene / sulfone / sulfoxide and nitrogen-containing molecular structures such as pyridine / pyrrole in coal have high thermal stability. Desulfurization and denitrification require relatively high temperatures. Flue gas micro-nano bubbles produce strong oxidizing free radicals such as ·OH and ·O in water, which can effectively destroy these stable sulfur- and nitrogen-containing organic molecular structures to form sulfur free radicals such as ·SH and RS· and nitrogen free radicals such as ·NH2, ·NR2, and ·NO2. These free radicals have low thermal stability and are easier to remove, which can help the subsequent high-value utilization of solid fuels.

[0039] In other aspects, the method provided by the present application can be carried out at room temperature and pressure, with a simple operation method and mild operating conditions. At the same time, the gas source used in the present application is power plant flue gas, which is low in cost and easy to obtain. If the flue gas also contains a high concentration of Cl or NO x content, the solid fuel modification effect will be further improved.

[0040] In addition, after the flue gas is modified by micro-nano bubbles, the SO2 content in the flue gas will be effectively reduced. If there is a high concentration of Cl or NO in the flue gas, x The content can be reduced during the process of flue gas micro-nano bubble modification. The flue gas then enters the desulfurization tower 7, which can effectively reduce the operating load of the desulfurization tower 7, reduce the amount of desulfurizer used, save costs, and reduce the content of harmful gases discharged into the atmosphere. If multiple solid fuel modification devices are connected in series, they can even replace the role of the desulfurization tower 7. The coal washing wastewater obtained after solid-liquid separation of the modified mixed slurry can be connected to the desulfurization wastewater treatment unit without the need for an additional coal washing wastewater treatment system.

[0041] Furthermore, pure water is the best liquid solvent, and boiler drum water, domestic water or water deeply treated by a desulfurization wastewater treatment system (water treated by reverse osmosis, mechanical steam recompression or multiple-effect evaporation of the clean water in the upper part of the clarification tank) can also be used, thereby effectively reducing the modification cost.

[0042] Further, the solid fuel comprehensive modification device also includes a slurry conveying unit 2 and a slurry processing unit 3. The slurry conveying unit 2 is arranged between the modification unit 1 and the slurry processing unit 3, and is used to convey the modified mixed slurry into the slurry processing unit 3. The slurry conveying unit 2 includes at least one slurry conveying pipeline 21, one end of which is connected to the slurry outlet 16 of the water washing box 11, and the other end is connected to the slurry processing unit 3. At the same time, a screw propeller 22 is arranged inside the slurry conveying pipeline 21 to provide power for the mixed slurry transmission;

[0043] The slurry processing unit 3 is used to perform solid-liquid separation and drying treatment on the modified mixed slurry to obtain modified solid fuel. The slurry processing unit 3 includes a solid-liquid separation component 31 and a drying component 32. One end of the solid-liquid separation component 31 is connected to the slurry conveying pipeline 21, and the other end is connected to the drying component 32. It is used to perform solid-liquid separation on the modified mixed slurry and send the separated solid matter into the drying component 32 for drying to obtain modified solid fuel. The heat source of the drying component 32 can come from the flue gas, and the heating and drying function is realized through heat exchange.

[0044] Further, each group of water washing components in the modification unit 1 is connected in parallel. When there are N groups of water washing components, the modification unit 1 includes a main gas path 19 and N branch gas paths 18, so that the undesulfurized flue gas is divided into N paths and respectively passed into each group of water washing components; at the same time, each water washing box 11 in each group of water washing components is connected in parallel, and the air inlet 13 of each water washing box 11 is respectively connected to the branch gas path 18, so that the undesulfurized flue gas in the branch gas path 18 is respectively passed into each water washing box 11, and at the same time, the flue gas discharged from the outlet 14 of each water washing box 11 after the modification reaction is collected and then post-processed. Preferably, the number of water washing components is 3 to 5 groups, and the number of water washing boxes 11 in each group of water washing components is 4 to 8. In practical applications, the appropriate number of water washing components and water washing boxes 11 can be selected according to the flue gas concentration, the characteristics of the solid fuel and other factors.

[0045] Furthermore, the air inlet 13 is used to connect with the outlet of the dust collector 6 to pass the dedusted and undesulfurized flue gas into the modification unit 1. The flue gas composition is relatively complex, mainly CO2, SO2 and O2, and contains a small amount of escaped NO x , which is beneficial to the comprehensive modification of solid fuels.

[0046] According to another aspect of the present application, Figure 3 As shown, a power system including the above-mentioned solid fuel comprehensive modification device is provided, and the power system also includes a boiler 4, an economizer 5, a dust collector 6, a desulfurization tower 7 and a flue gas heat exchanger 8 which are connected in sequence along the flue gas flow direction. The air inlet 13 of the modification unit 1 is connected to the outlet of the dust collector 6 to feed the undesulfurized flue gas into the modification unit 1; the air outlet 14 of the modification unit 1 is respectively connected to the inlet of the desulfurization tower 7 and the inlet of the flue gas heat exchanger 8 to feed the flue gas after the modification reaction into the desulfurization tower 7 or the flue gas heat exchanger 8. In practical applications, the modification unit 1 can be used to partially replace or completely replace the desulfurization tower 7, so as to achieve the effect of comprehensive modification and synergistic desulfurization of solid fuel.

[0047] Furthermore, the drying component 32 is connected to the outlet of the boiler 4 to utilize the flue gas for heat exchange drying.

[0048] Furthermore, the outlet of the dust collector 6 is connected to the inlet of the desulfurization tower 7 and the air inlet 13 of the modification unit 1 respectively through the first control valve 71, so as to adjust the proportion of flue gas entering the modification unit 1 according to the working condition of the modification unit 1. The first control valve 71 can adjust the proportion of flue gas entering the modification unit 1 within the range of 0 to 100%. Generally, 100% of the undesulfurized flue gas can enter the modification unit 1. Alternatively, according to the working condition of the modification unit 1, such as the number of normally operating water washing boxes 11, the quality of the solid fuel to be modified, etc., a suitable proportion of undesulfurized flue gas can be sent to the modification unit 1, and the remaining undesulfurized flue gas can be sent to the desulfurization tower 7. When the modification unit 1 fails or needs to be shut down for maintenance regularly, it can be completely switched to the desulfurization tower 7.

[0049] Preferably, the main gas path 19 in the modification unit 1 is connected to each branch gas path 18 through the third control valve 73, and each branch gas path 18 is connected to the air inlet 13 of the water washing box 11 through the fourth control valve 74, so that the third control valve 73 and the fourth control valve 74 are used to perform secondary distribution on the undesulfurized flue gas entering the modification unit. When a group of water washing components or a water washing box 11 fails, the third control valve 73 and the fourth control valve 74 can be used to close the corresponding branch gas path 18 or the air inlet 13 to avoid affecting the normal operation of the entire solid fuel comprehensive modification device.

[0050] At the same time, the gas outlet 14 of the modification unit 1 is connected to the inlet of the desulfurization tower 7 and the inlet of the flue gas heat exchanger 8 respectively through the second control valve 72, so as to control the flue gas after the modification reaction to enter the desulfurization tower 7 or the flue gas heat exchanger 8 according to the working conditions of the modification unit 1. When the flue gas after the modification reaction meets the national emission standards, it can be directly introduced into the flue gas heat exchanger 8 for "whitening" treatment, and then discharged through the chimney 9, so that the role of the desulfurization tower 7 is completely replaced by the solid fuel comprehensive modification device; when the flue gas after the modification reaction does not meet the national emission standards, it can be introduced into the desulfurization tower 7 for further desulfurization reaction, and then sent to the flue gas heat exchanger 8 after the conditions are met, so that the role of the desulfurization tower 7 is partially replaced by the solid fuel comprehensive modification device, reducing the use of desulfurizers.

[0051] Preferably, the modification unit 1 further comprises a SO2 concentration detection component 17, which is disposed between the gas outlet 14 and the second control valve 72 to control the flue gas entering the desulfurization tower 7 or the flue gas heat exchanger 8 according to the SO2 concentration in the flue gas after the modification reaction.

[0052] Furthermore, the power system also includes a control device 10, which is connected to the first control valve 71, the second control valve 72, the third control valve 73 and the fourth control valve 74 to intelligently distribute and regulate the flue gas.

[0053] The present application will be further described below based on specific embodiments and comparative examples.

[0054] Example 1

[0055] S1 dissolving the coal to be modified in deionized water to obtain a mixed slurry;

[0056] S2 uses 3000ppm SO2+5%O2+15%CO2 mixed with the balance gas N2 to simulate the undesulfurized flue gas, and introduces it into the mixed slurry in the form of micro-nano bubbles to achieve comprehensive modification of solid fuel;

[0057] S3 performs solid-liquid separation and drying treatment on the modified mixed slurry to obtain modified coal.

[0058] Comparative Example 1

[0059] S1 dissolving the coal to be modified in deionized water to obtain a mixed slurry, and stirring the mixed slurry to achieve comprehensive modification of the solid fuel;

[0060] S2 performs solid-liquid separation and drying on the modified mixed slurry to obtain modified coal.

[0061] Comparative Example 2

[0062] S1 dissolving the coal to be modified in deionized water to obtain a mixed slurry;

[0063] S2 passes H2SO4 into the mixed slurry. Since the pH of the mixed slurry is stabilized at 2.5 after continuous introduction of undesulfurized flue gas, it is necessary to ensure that the pH of the mixed slurry is stabilized at 2.5. After a period of reaction, comprehensive modification of the solid fuel is achieved;

[0064] S3 performs solid-liquid separation and drying treatment on the modified mixed slurry to obtain modified coal.

[0065] Comparative Example 3

[0066] S1 dissolving the coal to be modified in deionized water to obtain a mixed slurry;

[0067] S2 uses 3000ppm SO2+5%O2+15%CO2 mixed with the balance gas N2 to simulate the undesulfurized flue gas and directly introduces it into the mixed slurry to achieve comprehensive modification of solid fuel;

[0068] S3 performs solid-liquid separation and drying treatment on the modified mixed slurry to obtain modified coal.

[0069] The modified coal obtained in Example 1 and Comparative Examples 1 to 3 were respectively subjected to demineralization performance testing, crystal structure testing, pore structure testing, and surface chemical composition and element content testing. The results are as follows: Figures 4 to 8 As shown, the flue gas micro-nano bubbles in the figure are the modified coal obtained in Example 1, the deionized water is the modified coal obtained in Comparative Example 1, the H2SO4 is the modified coal obtained in Comparative Example 2, and the flue gas is the modified coal obtained in Comparative Example 3.

[0070] (1) Demineralization performance test

[0071] Table 1 shows the content and occurrence forms of inorganic elements in the coal to be modified used in Example 1 and Comparative Examples 1 to 3.

[0072] Table 1 Content and occurrence form of inorganic elements in the coal to be modified

[0073]

[0074] Figure 2 is the removal rate of minerals in the modified coal obtained in Example 1 and Comparative Examples 1 to 3, Figure 3 is the total content of acid infusible minerals in the modified coal obtained in Example 1 and Comparative Examples 1 to 3, wherein:

[0075] Removal rate = Na / Ca / / Mg / Fe content in modified coal / Na / Ca / / Mg / Fe content in raw coal. Comprehensive removal rate = (Na+Ca+Mg+Fe) content in modified coal / (Na+Ca+Mg+Fe) content in raw coal.

[0076] from Figure 4It can be seen that compared with deionized water coal washing, acid washing and flue gas coal washing can effectively improve the mineral removal rate in coal. The removal rate of each element in flue gas coal washing is roughly equivalent to that in H2SO4 coal washing, while flue gas micro-nano bubble coal washing can further improve the mineral removal rate in coal. Figure 5 It can be seen that the additionally removed minerals are mainly acid-insoluble minerals (mainly silicates and aluminosilicates), which indicates that the flue gas micro-nano bubbles can react with acid-insoluble minerals, destroy the lattice structure, promote the transformation of acid-insoluble minerals, and thus improve the mineral removal rate.

[0077] (2) Crystal structure

[0078] The modified coal obtained in Example 1 and Comparative Examples 1 to 3 was subjected to XRD test and Raman test respectively to obtain the structural derivative behavior of the modified coal. The XRD results and Raman results were subjected to peak separation to obtain the following related parameters:

[0079] XRD: After peak separation of 002 peak, the aromaticity degree of coal is obtained, and the calculation formula is as follows:

[0080]

[0081] Wherein, d002 is the distance between the single layers of the aromatic layer of the coke microcrystal structure; Lc is the microcrystal stacking height perpendicular to the aromatic layer; La is the microcrystal size parallel to the aromatic layer; θ002 and θ100 are the diffraction angles corresponding to the 002 peak and the 100 peak respectively; β002 and β100 correspond to the half-height width of the 002 peak and the 100 peak; λ is the wavelength of the incident light, generally λ = 0.15406nm; k1 and k2 are the waveform factors, generally k1 = 0.89; k2 = 1.84.

[0082] The degree of aromaticity fa is used to characterize the degree of graphitization, and the integrated intensities (areas) of the 002 peak and the γ peak obtained by XRD peak fitting can represent the number of aromatic carbon atoms (Car) and the number of aliphatic carbon atoms (Cal), respectively.

[0083]

[0084] Figure 6 The microcrystalline structure parameters of the modified coal obtained in Example 1 and Comparative Examples 1 to 3 vary from Figure 6It can be seen that deionized water coal washing has no effect on the microcrystalline structure of coal, while H2SO4 and flue gas coal washing have almost the same effect on the microcrystalline structure of coal, mainly because the acid formed by flue gas dissolving in water also produces H ions, which is the same as the core essence of H2SO4. H ions will promote the breakage of branch chains or bridge chains in the coal structure, so they will promote the interlayer spacing of the microcrystalline structure (increase of d002) and the increase of stacking height (increase of Lc), and turn the macromolecular structure into a small molecular weight structure (decrease of La). With the breakage of bridge chains and branch chains, the remaining structures are stable structures, such as benzene rings, so the degree of aromaticity increases (increase of fa). After micro-nano bubble coal washing, the generated free radicals such as ·OH and ·O have higher electronic energy than ·H, and can also destroy benzene rings or heterocyclic organic structures, so they will further promote the increase of interlayer spacing and the formation of smaller molecular weight organic structures. The internal organic links between different aromatic layers will also be destroyed, resulting in a decrease in stacking height. The destruction of organic structures such as benzene rings leads to a significant decrease in the aromaticity of coal.

[0085] Raman: For the first order peak of Raman (800-2000cm -1 ) was processed into D1 peak, D2 peak, D3 peak, D4 peak and G peak, among which D1 peak was 1350cm -1 The peak, usually called the defect band, corresponds to the graphite lattice vibration mode with A1g symmetry and is attributed to in-plane defects such as defects and heteroatoms; the D2 peak is at 1620 cm -1 The peak is always present with the G1 peak, and its intensity decreases with the increase of carbon ordering degree. The D3 peak is usually a very wide band around 1500-1550cm-1, which is considered to be the manifestation of sp2 bonds in amorphous carbon, such as organic molecules, molecular fragments or functional groups in substances with low carbon ordering degree. The D3 peak may be related to the reaction site, thus affecting the reactivity of coke. The D4 peak is 1150cm-1, which only appears in substances with low carbon ordering degree, such as bituminous coal and coal coke. The D4 peak may be attributed to the sp3-sp2 mixing site at the edge of the crystallite or the stretching vibration of C-C and C=C of polyenes, and it may also be due to the reaction site. The G peak is 1580cm-1. -1 The peak corresponds to the stretching vibration peak of E2g symmetry in the aromatic layer of graphite crystal. The characteristics of Raman spectrum have been shown to have a good correlation with the degree of ordering of carbon structure. Therefore, Raman spectrum can be used to analyze the effect of heat treatment on the evolution of coke structure. The following three band area ratios are mainly calculated: I D1 / I G ,I D3 / I G and I G / I ALL , where I D1 / I G is the relative content of unstable structure, I D3 / I G is the loudness content of the amorphous structure, I G / I ALL is the relative content of graphite structure.

[0086] like Figure 7 As shown in the figure, after deionized water coal washing, ID1 / IG, ID3 / IG and IG / IALL are almost the same as those of the original coal, indicating that deionized water coal washing will not change the structure and content of residual carbon, amorphous carbon and graphite carbon in coal, while after H2SO4 and flue gas coal washing, ID1 / IG and ID3 / IG drop rapidly, and IG / IALL rises sharply, indicating that the H ions in the solution during H2SO4 and flue gas coal washing will promote the elimination of residual carbon and amorphous carbon, reduce the content of residual carbon and amorphous carbon in coal, thereby increasing the relative content of graphite carbon, which is manifested as an increase in the degree of graphitization. After coal washing with flue gas micro-nano bubbles, ID1 / IG and ID3 / IG showed an increasing trend, while IG / IALL dropped sharply. This was mainly because the high reaction activity of free radicals such as ·OH and ·O generated by flue gas micro-nano bubbles can destroy the graphite carbon structure (such as benzene ring or heterocyclic organic structure) and transform it into amorphous carbon and residual carbon. The comprehensive performance is that the relative content of residual carbon and amorphous carbon is higher than that of H2SO4 and flue gas washing. This fully shows that coal washing with flue gas micro-nano bubbles will promote the decomposition of graphite carbon structure and reduce the degree of aromatization of coal.

[0087] (3) Pore structure

[0088] The modified coal obtained in Example 1 and Comparative Examples 1 to 3 was analyzed by using an adsorption tester, the total specific surface area was tested by using the BET model, and the pore size distribution of the coke was determined by using the BJH model.

[0089] Table 2 Pore structure parameters of modified coal in Example 1 and Comparative Examples 1 to 3

[0090]

[0091] Table 2 shows the measured pore structure parameters of modified coal. Deionized water washing has little effect on the specific surface area and pore volume of coal. H2SO4 and flue gas washing will increase the micropore area, external surface area, total specific surface area and pore volume of coal to a certain extent due to the bond breaking effect of ·H radicals. After coal washing with flue gas micro-nano bubbles, due to the destructive effect of strong oxidizing free radicals such as ·OH and ·O, the molecular weight of the coal base is reduced, the degree of aromatization is reduced, the pores inside the coal are effectively opened, and a pore-rich structure is formed, which further increases the micropore area, external surface area, total specific surface area and pore volume of the coal.

[0092] (4) Surface chemical composition and element content

[0093] XPS test was performed on the modified coal obtained in Example 1 and Comparative Examples 1 to 3 to obtain the surface chemical composition and element content of the modified coal. The S2p and N1s spectra of the XPS results were subjected to peak separation, and the electron binding energies corresponding to different structures were as follows:

[0094] S2p:

[0095] Pyrite: Binding energy is between 158 and 159.6 eV.

[0096] Sulfide: Binding energy is between 161.2 and 163.6 eV.

[0097] Thiophene: The binding energy is between 164 and 164.4 eV.

[0098] Sulfoxide: The binding energy is between 165 and 166 eV.

[0099] Sulfone: The binding energy is between 167 and 168.3 eV.

[0100] Sulfate: The binding energy is between 168.4 and 175 eV.

[0101] N1s:

[0102] Pyridinic N (N-6): The binding energy is 398.7 eV ± 0.3 eV. This nitrogen atom is usually connected to a carbon atom and a hydrogen atom to form a five-membered ring structure.

[0103] Amino, imine, and amide nitrogen (NH): The binding energy is located at 399.8 eV ± 0.2 eV. These nitrogen atoms can form bonds with hydrogen, carbon, and / or other elements.

[0104] Pyrrolic and pyridonic N (N-5): The binding energy is at 400.3 eV ± 0.2 eV. These nitrogen atoms usually participate in the formation of five-membered or six-membered heterocyclic structures.

[0105] Quaternary Nitrogen (NQ): The binding energy is at 401.4 eV ± 0.3 eV. This nitrogen atom acts as a substituent in the aromatic graphene structure and is connected to four carbon atoms.

[0106] Pyridine-N-oxide or Ammonia (NO): The binding energy is at 402.8 eV. This nitrogen atom can be part of a pyridine ring, in which the nitrogen atom is oxidized, or it can be the nitrogen in an ammonia molecule.

[0107] Adsorbed Nitrogen Oxides (N-OX): The binding energy is located at 405.0 eV ± 0.5 eV. These nitrogen atoms usually form bonds with oxygen atoms and may be connected to other elements such as carbon or hydrogen.

[0108] Figure 8 The S / N distribution characteristics of the modified coal obtained in Example 1 and Comparative Examples 1 to 3 are as follows. Figure 8 It can be seen that water washing will not change the distribution of S forms in coal. H2SO4 and flue gas coal washing will remove some inorganic sulfur such as pyrite, water-soluble sulfides and sulfates in coal, but will not destroy the organic sulfur structure in the form of thiophene, sulfoxide and sulfone. Flue gas micro-nano bubble coal washing will promote the decomposition of some thiophenes in coal and convert them into sulfoxides and sulfones. It will also promote the decomposition of some sulfoxides and sulfones and convert them into sulfides and sulfates, ultimately reducing the overall content of organic sulfur in coal.

[0109] For N, from Figure 8 It can be seen that water washing will not change the distribution of N forms in coal, H2SO4 and flue gas coal washing will remove some NH (amino, imine, amide nitrogen), NQ (quaternary ammonium nitrogen), NO (oxidized pyridinic nitrogen or ammonia nitrogen), and N-OX (adsorbed nitrogen oxides) in coal, and will not destroy the organic nitrogen structure in the form of pyridinic nitrogen and pyrrolic nitrogen. Flue gas micro-nano bubble coal washing will promote the decomposition of some pyridinic nitrogen and pyrrolic nitrogen in coal and convert them into NH (amino, imine, amide nitrogen), NQ (quaternary ammonium nitrogen), NO (oxidized pyridinic nitrogen or ammonia nitrogen), and N-OX (adsorbed nitrogen oxides).

[0110] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A solid fuel comprehensive modification device based on flue gas micro-nano bubbles, characterized in that: The invention comprises a modification unit (1), wherein the modification unit (1) comprises at least one group of water washing components, each group of the water washing components comprises at least one water washing box (11), the water washing box (11) is used to hold the solid fuel to be modified, the water washing box (11) is provided with a water inlet (15), an air inlet (13), an air outlet (14) and a slurry outlet (16), the water inlet (15) is used to introduce a liquid solvent to form a mixed slurry; the air inlet (13) is used to introduce undesulfurized flue gas, and at the same time The air inlet (13) is provided with a micro-nano bubble generator (12) for passing undesulfurized flue gas into a mixed slurry in the form of micro-nano bubbles, thereby demineralizing the solid fuel and improving the physical and chemical properties of the solid fuel under the combined action of multiple free radicals generated by the micro-nano bubbles and complex flue gas components; the air outlet (14) is used to discharge the flue gas after the modification reaction; and the slurry outlet (16) is used to discharge the modified mixed slurry, thereby achieving comprehensive modification of the solid fuel.

2. The solid fuel comprehensive reforming device according to claim 1, characterized in that: The solid fuel comprehensive modification device further comprises a slurry conveying unit (2) and a slurry processing unit (3); the slurry conveying unit (2) is arranged between the modification unit (1) and the slurry processing unit (3) and is used to convey the modified mixed slurry into the slurry processing unit (3); the slurry processing unit (3) is used to perform solid-liquid separation and drying treatment on the modified mixed slurry to obtain modified solid fuel.

3. The solid fuel comprehensive reforming device according to claim 2, characterized in that: The slurry processing unit (3) comprises a solid-liquid separation component (31) and a drying component (32); one end of the solid-liquid separation component (31) is connected to the slurry conveying unit (2), and the other end of the solid-liquid separation component (31) is connected to the drying component (32), and is used to perform solid-liquid separation on the modified mixed slurry, and to convey the separated solid matter to the drying component (32) for drying, thereby obtaining a modified solid fuel.

4. The solid fuel comprehensive reforming device according to claim 1, characterized in that: The groups of water washing components in the modification unit (1) are connected in parallel, and the water washing boxes (11) in the water washing components are connected in parallel.

5. The solid fuel comprehensive reforming device according to claim 1, characterized in that: The air inlet (13) is used to be connected to the outlet of the dust collector (6) so as to allow the undesulfurized flue gas to enter the modification unit (1).

6. A power system comprising a solid fuel comprehensive reforming device as claimed in any one of claims 1 to 5, characterized in that: The power system further comprises a boiler (4), a dust collector (6), a desulfurization tower (7) and a flue gas heat exchanger (8) which are connected in sequence along the flue gas flow direction; the air inlet (13) of the modification unit (1) is connected to the outlet of the dust collector (6) so as to feed the undesulfurized flue gas into the modification unit (1); the air outlet (14) of the modification unit (1) is respectively connected to the inlet of the desulfurization tower (7) and the inlet of the flue gas heat exchanger (8) so as to feed the flue gas after the modification reaction into the desulfurization tower (7) or the flue gas heat exchanger (8).

7. The power system according to claim 6, characterized in that: The drying component (32) is connected to the outlet of the boiler (4) to utilize the flue gas for heat exchange drying.

8. The power system according to claim 6, characterized in that: The outlet of the dust collector (6) is connected to the inlet of the desulfurization tower (7) and the air inlet (13) of the modification unit (1) respectively through a first control valve (71), so as to adjust the proportion of flue gas entering the modification unit (1) according to the operating conditions of the modification unit (1); the air outlet (14) of the modification unit (1) is connected to the inlet of the desulfurization tower (7) and the inlet of the flue gas heat exchanger (8) respectively through a second control valve (72), so as to control the flue gas after the modification reaction to enter the desulfurization tower (7) or the flue gas heat exchanger (8) according to the operating conditions of the modification unit (1).

9. The power system according to claim 8, characterized in that: The modification unit (1) further comprises a SO2 concentration detection component (17), which is arranged between the gas outlet (14) and the second control valve (72) to control the flue gas entering the desulfurization tower (7) or the flue gas heat exchanger (8) according to the SO2 concentration in the flue gas after the modification reaction.

10. The power system according to claim 8, characterized in that The power system further comprises a control device (10), wherein the control device (10) is connected to a first control valve (71) and a second control valve (72) of the modification unit and is used for distributing flue gas.

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