CN114231332A - Phosphoric acid modified coal gangue, preparation method and application thereof, and composite fuel - Google Patents

Phosphoric acid modified coal gangue, preparation method and application thereof, and composite fuel Download PDF

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CN114231332A
CN114231332A CN202111541221.6A CN202111541221A CN114231332A CN 114231332 A CN114231332 A CN 114231332A CN 202111541221 A CN202111541221 A CN 202111541221A CN 114231332 A CN114231332 A CN 114231332A
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coal gangue
phosphoric acid
ash
acid modified
biomass
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贾相如
霍心广
柳少卿
丁雅倩
张剑
云峰
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Inner Mongolia University of Technology
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Inner Mongolia University of Technology
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L9/00—Treating solid fuels to improve their combustion
    • C10L9/10—Treating solid fuels to improve their combustion by using additives
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L5/00—Solid fuels
    • C10L5/40—Solid fuels essentially based on materials of non-mineral origin
    • C10L5/44—Solid fuels essentially based on materials of non-mineral origin on vegetable substances
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E50/00—Technologies for the production of fuel of non-fossil origin
    • Y02E50/10—Biofuels, e.g. bio-diesel
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E50/00—Technologies for the production of fuel of non-fossil origin
    • Y02E50/30—Fuel from waste, e.g. synthetic alcohol or diesel

Abstract

The invention provides phosphoric acid modified coal gangue, a preparation method and application thereof, and a composite fuel, and belongs to the technical field of solid waste utilization. The invention utilizes the kaolin component inherent in the coal gangue, and because the structure of the raw coal gangue sample is compact and the chemical activity is weaker, the coal gangue is accompanied by component volatilization and structural expansion in the high-temperature calcination process, most of the original inorganic mineral crystals in the calcined coal gangue are converted into amorphous state, so the activity of the coal gangue is greatly improved. The modification by phosphoric acid can lead the interior of the reaction chamber to generate chemical reaction, and more pores are generated to increase the adsorption capacity of the reaction chamber to alkali metals; the invention utilizes the kaolin component inherent in the coal gangue and the physical and chemical activity of the modified coal gangue, effectively reduces the discharge of alkali metal gaseous products in the biomass combustion process, and forms high-melting-point compounds such as alkali metal aluminosilicate with high melting point, alkali metal regular phosphate and the like, thereby effectively reducing the slag bonding phenomenon generated by biomass combustion.

Description

Phosphoric acid modified coal gangue, preparation method and application thereof, and composite fuel
Technical Field
The invention relates to the technical field of solid waste utilization, in particular to phosphoric acid modified coal gangue, a preparation method and application thereof and a composite fuel.
Background
The biomass energy becomes the fourth most energy source in the world due to the renewable property, rich resources and environmental friendliness, and is mainly characterized in that the modern biomass energy technology is utilized to process raw materials such as agricultural wastes, felling residues, livestock and poultry manure, municipal solid wastes, domestic sewage, industrial organic wastewater and the like into terminal products such as biomass granular fuel, biodiesel, biofuel ethanol and the like. Almost no sulfur dioxide is discharged in the later utilization process of the biomass fuel, the harm of acid rain and greenhouse effect caused by smoke generated in the utilization process of the biomass fuel is reduced, and the biomass energy has wider application prospect and development space, so that the development of the biomass fuel becomes an important means and development direction for solving energy problems and improving the environment of human beings.
However, in the process of biomass combustion, the biomass contains more moisture and alkaline metal substances (especially crop straws), so that ash deposition and slagging are easily caused during combustion to damage a combustion bed, and a sintering phenomenon may occur. The high alkali metal content (K, Na) in biomass results in a low ash melting point of the biomass, which causes many problems for the combustion process. In the combustion utilization process, high alkali metal content is an important factor causing ash accumulation, slag bonding and corrosion on the heating surface of the boiler, and the service life and the heat efficiency of the boiler are directly reduced; meanwhile, the high alkali metal content also easily causes agglomeration and slag bonding of bed materials to destroy fluidization in the bed, so that the combustion working condition is deteriorated.
In the prior art, for example, chinese patents CN107365609A, CN110423638A and CN103351094A disclose anti-slagging agents, which all have the disadvantages of high cost and tedious method, and the reason for the high cost is mainly that raw materials required for manufacturing the anti-slagging agent are all taken from chemical products, and a large amount of chemical reagents are required to be added in the manufacturing process, thereby increasing the cost; the main reason for the tedious method is that the preparation of the anti-slagging agent needs a complex chemical process flow.
Disclosure of Invention
In view of the above, the invention aims to provide a phosphoric acid modified coal gangue, a preparation method and an application thereof, and a composite fuel. The invention utilizes the waste coal gangue resources which are convenient to take and use, thereby reducing the cost to the maximum extent.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of phosphoric acid modified coal gangue, which comprises the following steps:
calcining the coal gangue to obtain a calcined product;
and mixing the calcined product with a phosphoric acid solution for modification to obtain the phosphoric acid modified coal gangue.
Preferably, the calcining temperature is 550-600 ℃, the time is 2-3 h, and the calcining is carried out in a protective atmosphere.
Preferably, the coal refuse has a particle size <0.125 mm.
Preferably, the use amount ratio of the phosphoric acid to the calcined product in the phosphoric acid solution is 24-48 mmol: 1g of the total weight of the composition.
Preferably, the concentration of the phosphoric acid solution is 3-6 mol/L.
Preferably, the modification temperature is 85-90 ℃ and the modification time is 4-6 h.
The invention also provides phosphoric acid modified coal gangue prepared by the preparation method of the technical scheme.
The invention also provides application of the phosphoric acid modified coal gangue in the technical scheme in the field of reducing biomass slagging.
Preferably, the application comprises the following steps:
and mixing the phosphoric acid modified coal gangue with biomass and then burning.
The invention also provides a composite fuel, which comprises the following components in percentage by mass:
according to the technical scheme, the phosphoric acid modified coal gangue accounts for 0-20%, the mass percentage of the phosphoric acid modified coal gangue is not 0, and the biomass accounts for 80-100%.
The invention provides a preparation method of phosphoric acid modified coal gangue, which comprises the following steps: calcining the coal gangue to obtain a calcined product; and mixing the calcined product with a phosphoric acid solution for modification to obtain the phosphoric acid modified coal gangue.
Compared with the prior art, the invention has the following beneficial effects:
the invention utilizes the kaolin component inherent in the coal gangue, and because the structure of the raw coal gangue sample is compact and the chemical activity is weaker, the coal gangue is accompanied by component volatilization and structural expansion in the high-temperature calcination process, most of the original inorganic mineral crystals in the calcined coal gangue are converted into amorphous state, so the activity of the coal gangue is greatly improved. The modification by phosphoric acid can lead the interior of the reaction chamber to generate chemical reaction, and more pores are generated to increase the adsorption capacity of the reaction chamber to alkali metals; the invention utilizes the kaolin component inherent in the coal gangue and the physical and chemical activity of the modified coal gangue, effectively reduces the discharge of alkali metal gaseous products in the biomass combustion process, and forms high-melting-point compounds such as alkali metal aluminosilicate, alkali metal silicoaluminophosphate and the like, thereby effectively reducing the slagging phenomenon generated by biomass combustion. The coal gangue is used as an additive for reducing the slag bonding of the biomass, so that on one hand, the reduction treatment and the resource utilization of the coal gangue solid waste can be realized; on the other hand, the addition of the coal gangue effectively reduces the slagging tendency in the biomass combustion process, and has special significance for realizing the full utilization of the biomass fuel;
according to the invention, phosphoric acid modified coal gangue with a certain proportion is added into biomass fuel to prepare the composite fuel, the ash content generated after the composite fuel is combusted contains more high-melting-point silicoaluminophosphates, the solid potassium content in the ash content is obviously different, and the solid potassium rate in the biomass ash content is obviously improved by adding the phosphoric acid modified coal gangue;
the composite fuel is prepared by taking the phosphoric acid modified coal gangue and the biomass straw as raw materials, the preparation cost is low, and the preparation process is simple and convenient.
Drawings
FIG. 1 is an SEM image of a material in example 1, wherein (a) is an original sample of wheat straw, (b) is an ash sample of wheat straw, (c) is a raw sample of coal gangue, and (d) is CG/PC-3 phosphoric acid modified coal gangue;
FIG. 2 shows the potassium fixation amount of wheat straw ash under the action of different additive types in example 1, wherein 1 is no additive, 2 is CG, 3 is CG/PC-3, and 4 is CG/PC-6;
FIG. 3 is a mechanism diagram of reducing biomass combustion slagging by phosphoric acid modified coal gangue;
FIG. 4 shows the amount of potassium fixed in wheat straw ash at different additive ratios in example 2, where 1 is 5 wt% CG/PC-6, 2 is 10 wt% CG/PC-6, 3 is 15 wt% CG/PC-6, and 4 is 20 wt% CG/PC-6.
Detailed Description
The invention provides a preparation method of phosphoric acid modified coal gangue, which comprises the following steps:
calcining the coal gangue to obtain a calcined product;
and mixing the calcined product with a phosphoric acid solution for modification to obtain the phosphoric acid modified coal gangue.
The invention calcines the coal gangue to obtain a calcined product.
In the present invention, the coal gangue preferably has a particle size <0.125 mm. The present invention preferably achieves the particle size range by crushing treatment with a crusher.
In the invention, the coal gangue is preferably dried before use, the temperature of the drying is preferably 105 ℃, and the time is preferably 12 hours. In the present invention, the drying is preferably performed in a drying oven.
In the invention, the calcination is preferably carried out at 550-600 ℃ for 2-3 h, and preferably in a protective atmosphere, preferably nitrogen. In the present invention, the calcination is preferably carried out in a tube furnace.
In the invention, the components of the coal gangue are volatilized and the structure of the coal gangue is expanded in the calcining process, and most of the original inorganic mineral crystals in the calcined coal gangue are converted into amorphous state, so that the activity of the coal gangue is greatly improved.
After the calcined product is obtained, the calcined product is mixed with a phosphoric acid solution for modification, and the phosphoric acid modified coal gangue is obtained.
In the invention, the dosage ratio of phosphoric acid to the calcined product in the phosphoric acid solution is preferably 24-48 mmol: 1g of the total weight of the composition.
In the invention, the concentration of the phosphoric acid solution is preferably 3-6 mol/L. According to the invention, 15mol/L standard phosphoric acid solution is preferably selected, deionized water is adopted for constant volume respectively, and 3-6 mol/L phosphoric acid solution is obtained.
In the invention, the modification temperature is preferably 85-90 ℃, and the time is preferably 4-6 h.
According to the invention, the phosphoric acid modification is adopted, so that chemical reaction can be generated in the calcined coal gangue, and more pores are generated to increase the adsorption capacity of the calcined coal gangue on alkali metals.
After the modification is finished, the obtained modified product is preferably dried in a drying oven at 70 ℃ overnight to obtain the phosphoric acid modified coal gangue.
The invention also provides phosphoric acid modified coal gangue prepared by the preparation method of the technical scheme.
The invention also provides application of the phosphoric acid modified coal gangue in the technical scheme in the field of reducing biomass slagging.
In the present invention, said application preferably comprises the following steps:
and mixing the phosphoric acid modified coal gangue with biomass and then burning.
The invention also provides a composite fuel, which comprises the following components in percentage by mass:
according to the technical scheme, the phosphoric acid modified coal gangue accounts for 0-20%, the mass percentage of the phosphoric acid modified coal gangue is not 0, and the biomass accounts for 80-100%.
In the present invention, the biomass is preferably wheat straw.
In the present invention, the particle size of the wheat straw is preferably <0.125 mm.
In the invention, the ash generated after the composite fuel is combusted contains more high-melting-point silicoaluminophosphates, the solid potassium content in the ash is obviously different, and the solid potassium rate in the biomass ash can be obviously improved by adding the phosphoric acid modified coal gangue.
In order to further illustrate the invention, the phosphoric acid modified coal gangue provided by the invention, the preparation method and the application thereof and the composite fuel are described in detail by combining the examples, but the examples are not to be construed as limiting the protection scope of the invention.
Example 1
Crushing raw Coal Gangue (CG) and biomass wheat straws by a crusher, screening out a sample with a particle size of <120 meshes (<0.125mm), and drying the sample in a drying oven at 105 ℃ for 12 hours.
2) And (3) taking a raw coal gangue sample, and putting the raw coal gangue sample into a tubular furnace to be calcined for 2 hours at the constant temperature of 550 ℃ under the nitrogen atmosphere.
3) Taking 15mol/L standard phosphoric acid solution, and respectively metering 3mol/L phosphoric acid solution and 6mol/L phosphoric acid solution by using deionized water. Then, 10g of Calcined Coal Gangue (CCG) are taken out, 2 parts of the Calcined Coal Gangue (CCG) are mixed with 3mol/L and 6mol/L of phosphoric acid solution and the CCG respectively according to the metering ratio of 8mL/g, and the phosphoric acid solution and the CCG are marked as PC-3 and PC-6 respectively.
4) And (3) respectively carrying out constant temperature treatment on the mixture of the PC-3 and the PC-6 for 6 hours at 85 ℃ by adopting a constant temperature magnetic stirrer, and finally, putting the mixture into a drying box to dry overnight at 70 ℃, wherein the obtained product is the phosphoric acid modified coal gangue and is marked as CG/PC-3 or CG/PC-6.
5) CG/PC-3 or CG/PC-6 or CG and wheat straw are mixed according to the mass percent of the wheat straw accounting for 90 percent, and a micro stirrer is adopted for stirring treatment so as to ensure that the mixture is uniformly mixed and then combusted, and the method specifically comprises the following steps:
and (3) combustion of CG and wheat straws:
the method is characterized in that a self-built tube furnace is used for testing the characteristics of combustion slag formation after CG is added into wheat straws, and the method specifically comprises the following steps: crushing wheat straws in an electric crusher, and screening by using a standard sieve to ensure that the maximum particle size of the wheat straws is less than 125 mm; drying the screened straw sample in a drying box at constant temperature (105 ℃) for 12 hours, putting the straw sample into a self-sealing bag for storage after completely removing external water, and marking for later use; respectively mixing a certain amount of screened wheat straw samples with coal gangue samples, wherein the mass percent of the wheat straw is 90%, and the mass percent of the CG is 10%; and (3) respectively putting the mixed samples into porcelain boats, and respectively carrying out a 900 ℃ combustion experiment in a self-built tubular furnace.
Macroscopic morphology observation is carried out on the burnt wheat straw ash sample, and the wheat straw ash sample is found to have slight sintering phenomenon at 900 ℃, has hard and brittle texture, is adhered to the bottom of the porcelain boat in a glass state, and is not easy to be cut and crushed by a medicine spoon; the wheat straw mixed ash added with the coal gangue is fine and smooth in texture, loose in structure and easy to purge, and the ash slagging degree of the mixed sample is obviously reduced compared with that of pure wheat straw.
According to the biomass ash production standard of ASTM E1755-01(2020) Standard test method for Ash in Biomass, the ash production temperature is determined to be 600 ℃/700 ℃/800 ℃/900 ℃, and the constant temperature time is 3 hours. According to the ash forming rates of the ash samples prepared at the three temperatures, the ash forming rate after 800 ℃ is reduced, which shows that the release of alkali metal in the biomass tends to be stable at the temperature, so that the ash preparation experiment is carried out at 800 ℃ in the subsequent experiment.
Respectively putting 10g of wheat straw and 9g of a mixed sample of the wheat straw and CG into porcelain boats, then putting the porcelain boats into a muffle furnace, heating the porcelain boats from 20 ℃ to 800 ℃ at a heating rate of 20 ℃/min, staying at 250 ℃ for 30 minutes, finally keeping the temperature for 3 hours under the working condition of 800 ℃, and taking out the porcelain boats for later use after the equipment is cooled to room temperature.
The ash sample burnt for 3 hours at 800 ℃ is taken, and the characterization analysis is carried out on the compound components in the ash by adopting an X-ray diffractometer (XRD), and the test result shows that a large amount of SiO exists in the wheat straw ash2And at the same time a small amount of K2SiO3These low melting compounds contribute to a severe slagging tendency during the combustion of biomass; KAlSiO exists in biomass fuel ash added with coal gangue4These high melting compounds reduce the tendency of biomass to severely slag during combustion.
The analysis of the K element component in the wheat straw ash is carried out by means of an inductively coupled atomic emission spectrometer (ICP-AES), as shown in figure 2, the result shows that the wheat straw ash contains a small amount of K element, which shows that the K element in the wheat straw is released into the air in a large amount in the form of gaseous compounds in the combustion process, and further causes the serious corrosion phenomenon of a boiler furnace; the wheat straws added with the raw coal gangue contain more K elements, which shows that most of the K elements in the wheat straws are fixed in ash during the combustion process and form alkali metal aluminosilicate with high melting point, thereby further reducing the severe slagging tendency during the combustion process of the wheat straws.
The content of alkali metal in the wheat straw ash has important relation with the ash melting point, and the ash melting point affects the difficulty of combustion and slagging of the wheat straw. The wheat straw contains a large amount of alkali metal elements (mainly K elements) which are easy to react with SiO2The reaction produces eutectic potassium silicate with low melting point, resulting in a severe slagging tendency. Because the coal gangue contains kaolin components, the wheat straws added with the raw coal gangue can generate the following reaction in the combustion process to generate aluminium silicate potassium salt with high melting point, thereby reducing the slagging tendency of the straws, and the chemical reaction between the coal gangue and the wheat straws is shown as the following formula:
Al2Si2O5(OH)4→Al2O3·2SiO2+2H2O....................(1)
Al2O3·2SiO2+2KCl+H2O→2KAlSiO4+2HCl...............(2)
Al2O3·2SiO2+2KOH→2KAlSiO4+H2O....................(3)。
CG/PC-3 or CG/PC-6 and wheat straw combustion
A self-built tube furnace is used for testing the characteristics of the combustion slagging after 10 wt% of CG/PC-3 or CG/PC-6 is added into the wheat straws, and the method specifically comprises the following steps: crushing wheat straws in an electric crusher, and screening by using a standard sieve to ensure that the maximum particle size of the wheat straws is less than 125 mm; drying the screened straw sample in a drying box at constant temperature (105 ℃) for 12 hours, putting the straw sample into a self-sealing bag for storage after completely removing external water, and marking for later use; respectively mixing a certain amount of screened wheat straw samples with a PC-3/PC-6 test sample, wherein the mass percent of the wheat straw is 90%, and the mass percent of the CG/PC-3 or CG/PC-6 is 10%; and (3) respectively putting the mixed samples into porcelain boats, and respectively carrying out a 900 ℃ combustion experiment in a self-built tubular furnace.
Macroscopic morphology observation is carried out on the burnt wheat straw ash sample, and the texture of the wheat straw mixed ash sample added with CG/PC-3 or CG/PC-6 is finer and smoother at 900 ℃, the structure is loose and the blowing treatment is easier, so that the ash slagging degree of the mixed sample is reduced compared with that of the wheat straw added with CG.
At present, no unified standard exists in China for a method for preparing ash from straw ash samples, and according to the biomass ash preparation standard of ASTM E1755-01(2020) Standard test method for Ash in Biomass, the ash preparation temperature is determined to be 800 ℃, and the constant temperature time is 3 hours.
Respectively putting a 9g wheat straw and 1g CG/PC-3 mixed sample and a 9g wheat straw and 1gCG/PC-6 mixed sample into a porcelain boat, then putting the porcelain boat into a muffle furnace, heating the porcelain boat from 20 ℃ to 800 ℃ according to the heating rate of 20 ℃/min, staying at 250 ℃ for 30 minutes, finally keeping the temperature at 800 ℃ for 3 hours, and taking out the porcelain boat for later use after the device is cooled to room temperature.
Taking an ash sample which is burnt for 3 hours at 800 ℃, and performing characterization analysis on the components of compounds in the ash by XRD (X-ray diffraction), wherein the test result shows that K exists in the wheat straw ash added with CG/PC-3 or CG/PC-62CaP2O7、K3PO4、KAlP2O7And KAlSiO4These high melting compounds reduce the tendency of biomass to severely slag during combustion.
The ICP-AES is used for analyzing the K element component in the wheat straw ash, as shown in figure 2, the result shows that compared with the biomass fuel added with CG, the wheat straw fuel ash added with CG/PC-3 or CG/PC-6 contains more K elements, and the wheat straw fuel ash added with CG/PC-6 contains the highest K element, which shows that most of the K elements in the wheat straw are fixed in the ash during the combustion process, and alkali metal silicoaluminophosphates with high melting points are formed, so that the severe slagging tendency of the wheat straw during the combustion process is reduced.
The content of alkali metal in the wheat straw ash has important relation with the ash melting point, and the ash melting point affects the difficulty of combustion and slagging of the wheat straw. The wheat straw contains a large amount of alkali metal elements (mainly K elements) which are easy to react with SiO2The reaction produces eutectic potassium silicate with low melting point, resulting in a severe slagging tendency. As residual phosphoric acid in the modified coal gangue can be decomposed and gasified under the high-temperature condition, the adsorption activity of the modified coal gangue on alkali metals is further improved, the adsorption activity of CG/PC-6 is obviously highest, and the wheat straws added with CG/PC-3 or CG/PC-6 can generate alkali metal silicoaluminophosphates with high melting points in the combustion process, so that the slagging tendency of the straws is reduced.
Fig. 1 is a SEM image of a material, wherein (a) is an original sample of wheat straw, (b) is an ash sample of wheat straw, (c) is an original sample of coal gangue, and (d) is CG/PC-3 phosphoric acid modified coal gangue, as can be seen from (a) and (b) in fig. 1, the original sample structure of wheat straw is loose, and the ash sample structure of wheat straw is compact. As can be seen from fig. 1(c) and (d), the coal gangue has a flaky layered structure as it is, while the coal gangue after the phosphoric acid modification treatment has an irregular and porous structure.
Fig. 2 shows the solid potassium content of the wheat straw ash under the action of different additive types, wherein 1 is no additive, 2 is CG, 3 is CG/PC-3, and 4 is CG/PC-6, and it can be seen that when no additive is added to the biomass during combustion, the solid potassium content in the biomass ash is lower, and when the CG/PC-6 additive is added to the biomass fuel, the solid potassium content in the biomass ash is the highest.
Fig. 3 is a mechanism diagram of reducing biomass combustion slagging by using phosphoric acid modified coal gangue, and it can be known from the diagram that after the coal gangue is modified, the chemical and physical activities of the coal gangue are obviously improved, so that the alkali metal trapping capability of the coal gangue in the biomass combustion process is increased, the emission of corrosive alkali metal gas is reduced, the ash fusion temperature of ash is increased, and finally the serious slagging problem in the biomass combustion process is relieved.
Example 2
The method is characterized in that a self-built tubular furnace is used for testing the characteristics of burned slag after 5 wt%/15 wt%/20 wt% of CG/PC-6 is added into wheat straws, and the method specifically comprises the following steps: crushing wheat straws in an electric crusher, and screening by using a standard sieve to ensure that the maximum particle size of the wheat straws is less than 125 mm; drying the screened straw sample in a drying box at constant temperature (105 ℃) for 12 hours, putting the straw sample into a self-sealing bag for storage after completely removing external water, and marking for later use; respectively mixing a certain amount of screened wheat straw samples with CG/PC-6 test samples, wherein the mass percent of the wheat straw is 90%, and the mass percent of the CG/PC-6 is 5%/15%/20%; and (3) respectively putting the mixed samples into porcelain boats, and respectively carrying out a 900 ℃ combustion experiment in a self-built tubular furnace.
Macroscopic morphology observation is carried out on the burnt wheat straw ash sample, and compared with the situation that CG/PC-6 with other proportion is added, the wheat straw mixed ash sample with 15 wt% of CG/PC-6 is finer in texture, looser in structure and easier to blow and sweep, so that the effect of reducing the wheat straw slagging tendency is best when 15 wt% of CG/PC-6 is added.
At present, no unified standard exists in China for a method for preparing ash from straw ash samples, and according to the biomass ash preparation standard of ASTM E1755-01(2020) Standard test method for Ash in Biomass, the ash preparation temperature is determined to be 800 ℃, and the constant temperature time is 3 hours.
Respectively taking a mixed sample of 9.5g of wheat straw and 0.5g of CG/PC-6, a mixed sample of 8.5g of wheat straw and 1.5gCG/PC-6, and a mixed sample of 8g of wheat straw and 2g of CG/PC-6, putting the mixed sample into a porcelain boat, then putting the porcelain boat into a muffle furnace, heating the porcelain boat from 20 ℃ to 800 ℃ at a heating rate of 20 ℃/min, staying at 250 ℃ for 30 minutes, finally keeping the temperature for 3 hours under the working condition of 800 ℃, and taking out the porcelain boat for later use after the equipment is cooled to room temperature.
Taking an ash sample which is burnt for 3 hours at 800 ℃, and characterizing the components of compounds in the ash by XRDThe test result shows that K exists in the wheat straw ash added with CG/PC-62CaP2O7、K3PO4、KAlP2O7And KAlSiO4This indicates that the presence of P-containing species can promote the fixation of K species in the biomass in the residual ash due to high affinity to alkali metals, and these high melting compounds reduce the severe slagging tendency of the biomass during combustion.
The ICP-AES is used for carrying out component analysis on K elements in wheat straw ash added with PC-6 in different proportions, as shown in figure 4, the result shows that compared with biomass fuel added with 5 wt%/10 wt%/20 wt% CG/PC-6, the wheat straw fuel ash added with 15 wt% CG/PC-6 contains more K elements, which shows that most of the K elements in the wheat straws are fixed in the ash during the combustion process, alkali metal silicoaluminophosphates with high melting points are formed, and further the severe slagging tendency during the combustion process of the wheat straws is reduced.
The content of alkali metal in the wheat straw ash has important relation with the ash melting point, and the ash melting point affects the difficulty of combustion and slagging of the wheat straw. The wheat straw contains a large amount of alkali metal elements (mainly K elements) which are easy to react with SiO2The reaction produces eutectic potassium silicate with low melting point, resulting in a severe slagging tendency. As the residual phosphoric acid in the modified coal gangue is decomposed and gasified under the high-temperature condition, the adsorption activity of the modified coal gangue on alkali metals is further improved, the experimental result shows that the adsorption activity of the added 15 wt% CG/PC-6 is obviously the highest, and the wheat straws added with the 15 wt% CG/PC-6 can generate more alkali metal silicoaluminophosphates with high melting points in the combustion process, so that the slagging tendency of the straws is more effectively reduced.
The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be construed as the protection scope of the present invention.

Claims (10)

1. The preparation method of the phosphoric acid modified coal gangue is characterized by comprising the following steps:
calcining the coal gangue to obtain a calcined product;
and mixing the calcined product with a phosphoric acid solution for modification to obtain the phosphoric acid modified coal gangue.
2. The preparation method according to claim 1, wherein the calcination is carried out at 550-600 ℃ for 2-3 h in a protective atmosphere.
3. The method of claim 1, wherein the coal refuse has a particle size <0.125 mm.
4. The preparation method according to claim 1, wherein the amount ratio of the phosphoric acid to the calcined product in the phosphoric acid solution is 24 to 48 mmol: 1g of the total weight of the composition.
5. The method according to claim 1 or 4, wherein the concentration of the phosphoric acid solution is 3 to 6 mol/L.
6. The preparation method according to claim 1, wherein the modification temperature is 85-90 ℃ and the modification time is 4-6 h.
7. The phosphoric acid modified coal gangue prepared by the preparation method of any one of claims 1 to 6.
8. The application of the phosphoric acid modified coal gangue as defined in claim 7 in the field of reducing biomass slagging.
9. Use according to claim 8, characterized in that it comprises the following steps:
and mixing the phosphoric acid modified coal gangue with biomass and then burning.
10. The composite fuel is characterized by comprising the following components in percentage by mass:
the phosphoric acid modified coal gangue of claim 7, wherein the mass percentage of the phosphoric acid modified coal gangue is not 0, and the biomass is 80-100%.
CN202111541221.6A 2021-12-16 2021-12-16 Phosphoric acid modified coal gangue, preparation method and application thereof, and composite fuel Pending CN114231332A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116003013A (en) * 2023-02-07 2023-04-25 中国矿业大学 Heat conduction modifier, gangue-based underground heat conduction material and preparation method thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1298175A (en) * 1970-02-24 1972-11-29 Trw Inc Extraction of sulfur compounds from pulverized coal
CN1274012A (en) * 2000-05-19 2000-11-22 燕民才 Combustion improver for promoting sinter of iron concentrate
JP2005307117A (en) * 2004-04-26 2005-11-04 Taiho Ind Co Ltd Fuel additive for preventing slagging and method for burning fuel
CN108384597A (en) * 2018-02-06 2018-08-10 武汉凯迪绿色能源开发运营有限公司 Biomass recirculating fluidized bed boiler anti-coking additive and its preparation and application method
CN110885709A (en) * 2019-11-29 2020-03-17 华中科技大学 Biomass fuel with low emission of ultrafine particles in combustion and preparation method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1298175A (en) * 1970-02-24 1972-11-29 Trw Inc Extraction of sulfur compounds from pulverized coal
CN1274012A (en) * 2000-05-19 2000-11-22 燕民才 Combustion improver for promoting sinter of iron concentrate
JP2005307117A (en) * 2004-04-26 2005-11-04 Taiho Ind Co Ltd Fuel additive for preventing slagging and method for burning fuel
CN108384597A (en) * 2018-02-06 2018-08-10 武汉凯迪绿色能源开发运营有限公司 Biomass recirculating fluidized bed boiler anti-coking additive and its preparation and application method
CN110885709A (en) * 2019-11-29 2020-03-17 华中科技大学 Biomass fuel with low emission of ultrafine particles in combustion and preparation method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
陈昆柏: "《固体废物环境管理丛书 工业固体废物处理与处置》", 30 June 2017, 河南科学技术出版社 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116003013A (en) * 2023-02-07 2023-04-25 中国矿业大学 Heat conduction modifier, gangue-based underground heat conduction material and preparation method thereof

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