A method for regulating the yield and composition of coal pyrolysis products

Abstract

This invention discloses a method for controlling the yield and composition of coal pyrolysis products. The method includes: pyrolyzing a coal mixture consisting of coal and oil, coal and catalyst, or coal, oil, and catalyst; separating the pyrolysis volatiles through condensation to obtain coal tar, pyrolysis gas, and semi-coke; wherein the coal is lignite, bituminous coal, or a mixture thereof processed to obtain deashed coal, or different coal petrographic components; and the oil is medium-low temperature coal tar heavy oil, medium-low temperature coal tar and its distillate oil, or organic reagents and mixtures thereof with a boiling point of 50-130℃. Based on the composition and structure of coal, this invention starts from the source of coal pyrolysis, influencing the pyrolysis behavior of the coal itself through the addition of oil and catalyst, promoting the release of coal pyrolysis volatiles from the source and controlling the composition of coal pyrolysis volatiles, thereby achieving increased oil production from coal pyrolysis and controlling the composition and distribution of coal tar.

Description

Technical Field

[0001] This invention relates to a coal pyrolysis method, specifically to a method for controlling the yield and composition of coal pyrolysis products. Background Technology

[0002] Coal is an organic rock containing elements such as carbon, hydrogen, oxygen, nitrogen, and sulfur. The pyrolysis products of coal include coke / semi-coke, coal tar, and coal gas. Pyrolysis is a crucial means of achieving coal fractionation, multi-value production, clean and efficient utilization, and large-scale processing. Coal pyrolysis products can be further converted into high-value products such as specialty fuels, chemicals, and carbon-based materials. Furthermore, coal tar is rich in important chemicals or intermediates that cannot be produced by petrochemical processes, holding a vital position among global chemical raw materials. Compared to other coal thermal conversion technologies such as coal gasification and coal liquefaction, coal pyrolysis technology boasts the lowest carbon emissions, highest thermal efficiency, longest product chain, and lowest investment cost, exhibiting significant technological and economic advantages. However, existing coal pyrolysis technologies still face some pressing problems, such as low coal tar yield and poor quality.

[0003] Chinese invention patent CN104479711A discloses a method for improving the yield of coal tar from low-rank coal pyrolysis. The method includes: (1) Raw coal drying: Vacuum drying of coal with a particle size less than 200 mesh for 3-24 hours at a temperature of 40-80℃ and a pressure of 100-1000 Pa to obtain dried coal; (2) Swelling treatment: Mixing the dried coal obtained in step (1) with a mixed solvent, swelling for 0.5-2 hours at a temperature of 60-100℃ and a pressure of 0.1-1.5 MPa, then filtering and vacuum drying to obtain swollen coal. The mixed solvent consists of alcohols and tetrahydrofuran in a volume ratio of 2-10: 1. Composition, wherein the alcohol is a mixture of methanol: ethanol: ethylene glycol in a volume ratio of 1:(1~2):(1~5); (3) Pyrolysis reaction: Under inert gas protection, the tubular furnace is heated to 500~700℃, and the swollen coal obtained in step (2) is pushed into the tubular furnace for pyrolysis reaction. The reaction lasts for 0.25~0.5 hours. Then the coal sample is quickly removed under inert gas protection and cooled to below 200℃. The pyrolyzed coal sample is removed from the tubular furnace and cooled to room temperature; (4) Collection of coal tar. This method can improve the coal tar yield, thereby increasing the coal tar yield by 0.2~3.4% and the total volatile matter yield by 3~7%.

[0004] Chinese invention patent with publication number CN112280580A discloses a method for improving the quality and oil content of pulverized coal pyrolysis in a fluidized bed. The method involves mixing coal and biomass in a certain proportion, using a fluidized bed as a reactor, introducing conveying gas and fluidizing gas, and carrying out a pyrolysis reaction under certain pressure conditions. The yield of the co-pyrolysis oil is higher than that of coal pyrolysis oil alone, and the aromatic content of the co-pyrolysis oil is increased.

[0005] Chinese invention patent CN118064173A discloses a method for increasing the phenolic compound content of coal pyrolysis tar. Under temperature conditions of 400-600℃, low-rank coal pyrolysis volatiles react with an Fe2Ca2O5 catalyst, causing catalytic cracking of large-molecule oxygen-containing heterocyclic compounds in the tar, reducing the content of these compounds, and significantly increasing the phenolic content in the tar. This method is a catalytic modification of coal pyrolysis volatiles, utilizing the secondary reactions of volatiles to regulate the tar composition.

[0006] Chinese invention patent CN113980699A discloses a method for improving the yield of lignite pyrolysis tar. The method involves treating raw lignite through a combined process of hydrothermal treatment and swelling, including hydrothermal upgrading, drying, swelling treatment, and organic solvent recovery and drying. This process increases the H / C atomic ratio of the upgraded coal, increases the hydrogen free radical content during pyrolysis, and amplifies the increase in the H / C atomic ratio during swelling, thereby improving the yield of lignite pyrolysis tar.

[0007] In summary, researchers have conducted extensive studies on the coal pyrolysis process, finding that changes in pyrolysis process parameters such as final pyrolysis temperature, heating rate, pressure, and atmosphere all affect the chemical reactions occurring during coal pyrolysis and the final distribution of pyrolysis products. However, existing methods for improving coal pyrolysis tar yield are complex, difficult to implement, and offer limited improvement in tar yield. Catalytic conversion of coal pyrolysis volatiles can effectively control the composition of coal pyrolysis tar, but this process suffers from rapid catalyst deactivation and difficulty in catalyst regeneration. Furthermore, this method of controlling tar composition comes at the cost of sacrificing tar yield.

[0008] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0009] The purpose of this invention is to provide a method for controlling the yield and composition of coal pyrolysis products, which solves the problems of low yield and poor quality of existing coal pyrolysis tar. The method of this invention can effectively improve the yield of coal pyrolysis tar and control the composition of coal tar.

[0010] To achieve the above objectives, the present invention provides a method for controlling the yield and composition of coal pyrolysis products, the method comprising: This invention utilizes a coal mixture consisting of coal and oil, coal and catalyst, or coal, oil, and catalyst. The coal mixture is pyrolyzed at 300-800°C in a pyrolysis carrier gas atmosphere at a reaction pressure of 0-2 MPa. The pyrolysis volatiles are separated by condensation to obtain coal tar, pyrolysis gas, and semi-coke. The coal is lignite, bituminous coal, or a mixture thereof, processed to obtain deashed coal or different petrographic components of the coal. The petrographic components include: pithite, vitrinite, and inertinite. The oil is medium-low temperature coal tar heavy oil, medium-low temperature coal tar and its distillate oil, or organic reagents and mixtures thereof with a boiling point of 50-130°C. The organic reagents are selected from any one or more of methanol, ethanol, tetrahydrofuran, acetone, acetic acid, n-heptane, and benzene. The catalyst is any one or more of halides, sulfates, nitrates, phosphates, acetates, oxalates, and sulfides of Al, alkali metals, alkaline earth metals, and transition metals. The catalyst used in this invention does not suffer from deactivation and is easy to mass-produce.

[0011] For different types of coal, this invention employs various combinations of coal and oil, coal and catalyst, or coal, oil, and catalyst for pyrolysis. The yield of coal tar and the aromatic content in the coal tar can be controlled by adjusting the type and combination of oil, pyrolysis temperature, pyrolysis carrier gas, pyrolysis pressure, and the type, particle size, and dosage of catalyst. For lignite, due to its high content of oxygen-containing functional groups and relatively loose structure, a combination of coal and oil, or coal, oil, and catalyst, is preferred for pyrolysis. Introducing medium- or low-temperature coal tar or low-boiling-point organic reagents can enhance the swelling effect of coal particles, promote the release of volatiles, and inhibit secondary condensation reactions of free radicals, thereby increasing the coal tar yield and reducing the oxygen-containing compound content in the tar. In this case, the pyrolysis temperature is preferably controlled within a relatively low or medium range to avoid excessive tar cracking. For bituminous coal, due to its well-developed aromatic structure and susceptibility to secondary condensation reactions, a synergistic system of coal, oil, and catalyst is preferred for pyrolysis. Oil is used to improve mass transfer conditions and stabilize pyrolysis intermediates, while catalysts promote the cleavage of aliphatic side chains, the removal of oxygen-containing functional groups, and aromatization reactions. By controlling the type and amount of catalyst, the aromatic content in tar can be increased, while further conversion of tar to gas or semi-coke can be inhibited. For the chitinous group, the formation of liquid products can be promoted by combining milder pyrolysis conditions with the oil phase; for the vitrinite group, the conversion of aromatic structures can be enhanced through the synergistic effect of the oil phase and catalyst, increasing the proportion of aromatics in the tar; for the inert group, its reactivity can be improved by reducing particle size, introducing an oil phase with strong swelling capacity, and adding an appropriate amount of catalyst, thereby promoting its conversion to liquid products. The mass ratio of oil to coal, the mass ratio of catalyst to coal, and the catalyst particle size can be adjusted according to the specific coal type to optimize mass transfer and reaction efficiency during the reaction process. Generally, smaller catalyst particle sizes are beneficial to improving their dispersibility and catalytic activity, while an appropriate amount of catalyst can achieve a balance between promoting cracking and inhibiting excessive cracking. By adjusting the pyrolysis carrier gas flow rate, the residence time of volatiles in the reaction zone can be controlled. A higher carrier gas velocity facilitates the rapid removal of volatiles, thereby reducing secondary cracking and condensation reactions in tar and increasing tar yield. Furthermore, by adjusting the type of pyrolysis carrier gas, the reaction pathway and transformation behavior of volatiles in the reaction zone can be controlled. For example, using an H2 atmosphere can stabilize free radicals generated during pyrolysis through hydrogen supply, inhibiting condensation reactions and promoting the formation of light components and aromatics in the tar. Adjusting the reaction pressure within the range of 0–2 MPa can alter the residence and transport behavior of volatiles in the system. Moderately increasing the pressure enhances the interaction between volatiles and the reaction medium, but excessively high pressure may promote condensation reactions; therefore, optimization selection is necessary based on the coal type and target product.

[0012] Preferably, the organic reagent is a mixed solvent of THF, ethanol, benzene, acetic acid, acetone, and n-heptane. More preferably, the volume ratio of THF:ethanol:benzene:acetic acid:acetone:n-heptane is 0.7:0.7:4.5:0.7:0.7:0.7.

[0013] Preferably, the distillate oil of the medium- and low-temperature coal tar is selected from distillate oil with a boiling point of less than 210°C - light oil, distillate oil with a boiling point of 210~230°C - phenol oil, distillate oil with a boiling point of 230~270°C - naphthalene oil, or distillate oil with a boiling point of greater than 270°C - wash oil.

[0014] Preferably, the alkali metal is selected from Na and / or K; the alkaline earth metal is selected from Ca and / or Mg; and the transition metal is selected from any one or more of Zn, Mn, Fe, Cu, Co, Ni, Cr, W, and Mo.

[0015] Preferably, the coal has a particle size of <0.5mm and a moisture content of ≤10%. The coal is deashed by HCl / HF stepwise deashing treatment to obtain deashed coal, or it is prepared by flotation and sedimentation to separate microscopic components to obtain vitrinite-enriched coal sample, and then deashed by HCl / HF stepwise deashing treatment to obtain deashed vitrinite-enriched coal sample, and then constitutes the coal mixture with oil and / or catalyst.

[0016] Preferably, the catalyst is added in any of the following ways: (1) Mechanical mixing of coal and catalyst; (2) Ion exchange between coal and catalyst; (3) Coal and catalyst are loaded by impregnation.

[0017] The mechanical mixing method involves distributing the active metal on the outer surface of the coal sample (e.g., grinding and loading the coal with metal salts); the impregnation method involves dispersing the active metal in the porous structure of the coal (e.g., loading the coal with a metal salt solution); and the ion exchange method involves combining the active metal component with the functional group structure of the coal. Depending on the tightness of the binding between the active metal and the coal structure, the ion exchange method introduces the active metal into the molecular structure, which has the greatest impact on the coal pyrolysis process.

[0018] More preferably, when the coal mixture consists of coal, oil, and a catalyst, the coal is prepared by impregnating the coal in oil containing the catalyst; when the coal mixture consists of coal and a catalyst, the coal is impregnated in an aqueous solution containing the catalyst, and after loading, the solvent is evaporated and dried to obtain the coal mixture.

[0019] More preferably, in the coal-catalyst ion exchange method, the metal salt is prepared into an ethanol solution with a concentration of 0.1~0.4 mol / L, the mass ratio of coal to ethanol salt solution is 1:1~40, mixed and ultrasonically dispersed for 0~30 min, and 0.1~0.5 mol / L NaOH solution is added dropwise to adjust the pH value to between 8 and 9. The mixture is then filtered, washed with deionized water until neutral, and dried to obtain a metal ion-exchanged coal sample. The amount of ion-exchanged metal is ≤1%, which is the metal loading / catalyst addition amount, meaning that the metal addition amount needs to be less than 1% of the corresponding raw material mass.

[0020] Preferably, in the method of supporting coal and catalyst metal, the concentration of the metal salt in ethanol-water is 0.001~0.002 g / mL, the ratio of coal to ethanol-water is 1 g : 1~40 mL, and the mixture is dried to obtain a metal-loaded coal sample, wherein the amount of ion-exchange metal is ≤1%.

[0021] Preferably, in the coal and oil or the coal mixture with the catalyst, the mass ratio of coal to oil is 1:1 to 20; and in the coal mixture with the catalyst, the metal loading is 0.5 to 0.8% of the coal mass.

[0022] More preferably, in the coal mixture of coal, oil and catalyst, the oil contains the catalyst, and the concentration of the catalyst is 0.001~0.002 g / mL.

[0023] Preferably, the pyrolysis temperature is 500~800℃, and the pyrolysis reaction pressure is 0.04~0.1MPa. More preferably, the pyrolysis temperature is 550~650℃.

[0024] Preferably, in the pyrolysis, the pyrolysis carrier gas is selected from any one or more of N2, He, CH4, H2, CO2, and CO. More preferably, the carrier is selected from H2, which significantly increases the relative content of aromatics and acidic compounds.

[0025] Preferably, the amount of catalyst added is ≤1% of the coal mass, and the particle size of the catalyst is ≤100µm. More preferably, the particle size of the catalyst is 20µm ≤ 70µm.

[0026] Preferably, the mass of the coal accounts for 30-50% of the total mass of the coal and oil.

[0027] Preferably, the coal and oil, or the mixture thereof and the catalyst, are preheated at 100-200°C, then pyrolyzed, or the oil is distilled off above its boiling point after preheating and returned to the oil source. After pyrolysis, the coal tar is condensed and recovered, and a portion of the distillate with a boiling point ≤200°C is returned as oil for recycling.

[0028] The preheating treatment can reduce the viscosity of the kerosene slurry raw material, increase its fluidity, and improve the uniformity of coal, oil, and metal catalyst; enhance the swelling effect of solvent / oil on coal; reduce the temperature gradient and avoid local overheating caused by rapid heating inside the coal particles; and cause weak bonds in the coal (such as hydrogen bonds, some ether bonds, and side chain bonds) to begin to loosen or break, thereby weakening the coal structure and improving the pyrolysis effect.

[0029] The method for controlling the yield and composition of coal pyrolysis products of the present invention solves the problems of low yield and poor quality of existing coal pyrolysis tar, and has the following advantages: (1) The method of the present invention is based on the composition and structure of coal. Starting from the source of coal pyrolysis, the method affects the pyrolysis behavior of coal itself by adding oil and catalyst, thereby promoting the release of coal pyrolysis volatiles and regulating the composition of coal pyrolysis volatiles from the source, so as to achieve the increase of coal pyrolysis oil and the regulation of coal tar composition and distribution. (2) In the method of the present invention, the addition of oil has the effects of swelling, dissociation, extraction and dissolution of coal during the co-pyrolysis process, promoting the generation and release of pyrolysis volatiles in the coal itself. Different oil compositions have selective effects on the swelling, dissociation, extraction and dissolution of different structures in the coal during the pyrolysis process. By changing the composition of the oil, the composition of pyrolysis volatiles can be controlled, that is, the composition and structure of tar and coal gas can be controlled.

[0030] (3) In the method of the present invention, the added catalyst can form catalytic active sites on the surface of coal or in the pores of coal, promote the cracking reaction of the coal macromolecular structure, promote the generation of coal pyrolysis volatiles, and at the same time, the active sites generated by different catalysts have different functions and will be selective for different bonds in the coal structure, thereby realizing the regulation of the composition of pyrolysis volatiles, that is, the regulation of the composition and structure of tar and coal gas. (4) In the method of this invention, during the pyrolysis of oil and catalyst with coal, oil and catalyst have a synergistic effect. The swelling, dissociation, extraction, and dissolution of coal by oil exposes more sites for binding with the catalyst. Oil can promote the dispersion of the catalyst. The catalyst can act on the pyrolysis of oil, and can further regulate the composition of its pyrolysis oil. In addition, at the end of pyrolysis, oil acts as a binder between coal and coke, causing the coal / coke particles to bond together, and can upgrade the final pyrolysis product - powdered coke - into block coke. This can solve the problems of difficult utilization and easy spontaneous combustion of coal powdered coke;

[0031] (5) In the method of the present invention, the oil can be recovered and used as recycled oil. The amount of catalyst added is ≤1%, which does not affect the further use of coal coke. The method of the present invention is simple, the catalyst preparation method is simple, the cost is low, the equipment investment is small, and it is easy to produce on a large scale. Attached Figure Description

[0032] Figure 1The yield diagram shows the pyrolysis products of RD, RD-n-heptane, RD-acetic acid, RD-benzene, RD-ethanol, RD-THF and RD-acetone.

[0033] Figure 2 The graph shows the relative content changes of group components in coal tar for RD, RD-n-heptane, RD-acetic acid, RD-benzene, RD-ethanol, RD-THF and RD-acetone.

[0034] Figure 3 The graph shows the relative content changes of BTXN (benzene, toluene, xylene, and naphthalene) in coal tar of RD, RD-n-heptane, RD-acetic acid, RD-benzene, RD-ethanol, RD-THF, and RD-acetone.

[0035] Figure 4 The three-phase yield of S5H5 at 200℃, 300℃, 400℃, 500℃, 550℃, 600℃, 650℃, 700℃ and 800℃.

[0036] Figure 5 The distribution of group components of S5H5 at 200℃, 300℃, 400℃, 500℃, 550℃, 600℃, 650℃, 700℃ and 800℃.

[0037] Figure 6 The three-phase yield (a) and group component distribution (b) of S5H5 at 2.0 MPa, 2.2 MPa and 2.4 MPa are shown.

[0038] Figure 7 The graph shows the theoretical values ​​and actual yields of the pyrolysis products of SD, HCT, S3H7, S4H6, S5H5, and S6H4.

[0039] Figure 8 The graph shows the yield variation of PCX (a) and aromatic hydrocarbon 1-4 rings (b) in coal tar of SD, HCT, S3H7, S4H6, S5H5 and S6H4.

[0040] Figure 9 The graph shows the theoretical and actual yields of the pyrolysis products of SD-T, SD-QY, SD-FY, SD-NY, and SD-XY. Detailed Implementation

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] It should be noted that: Unless otherwise specified in the examples, conditions should be followed according to standard conditions or the manufacturer's recommendations. Instruments whose manufacturers are not specified are all commercially available products. Raw materials and reagents whose manufacturers are not specified are all commercially available goods or can be prepared using known methods.

[0043] In this invention, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are used only for simplicity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0044] The features mentioned in this invention can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification, provided that there is no contradiction in the combination of these features. Each feature disclosed in the specification can be replaced by any alternative feature that provides the same, equivalent, or similar purpose. Therefore, unless otherwise specified, the disclosed features are merely general examples of equivalent or similar features.

[0045] In the description of this invention, it should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] Existing kerosene co-pyrolysis technologies use heavy oil as the hydrogen donor solvent, dissolving coal in the heavy oil. The coal and oil undergo simultaneous hydrocracking under high temperature and pressure in a reactor. The high pressure (10-20 MPa) conditions place stringent requirements on equipment materials and processing precision, resulting in high investment costs. Furthermore, these technologies suffer from problems such as poor kerosene-oil compatibility, low catalyst activity and dispersibility, equipment erosion, solid-liquid separation, and large, unutilized residue. Therefore, this invention provides a method for controlling the yield and composition of coal pyrolysis products. This method eliminates the stringent high-pressure conditions and utilizes the synergistic effect of coal and oil under high-temperature conditions. Applying this method to the coal pyrolysis process will effectively improve coal pyrolysis efficiency, tar yield, and quality.

[0047] However, the mechanism of coal-oil co-pyrolysis is complex, including: 1) solvent swelling of coal: increasing tar yield; multiple solvents are superior to single solvents (eliminating / mitigating cross-linking); 2) coal and oil co-pyrolysis: under high temperature conditions, the swelling, extraction, and dissociation of coal by oil are enhanced, while oil, as a medium, effectively increases the mass transfer of catalyst and active hydrogen. Therefore, this invention studies the effects of different solvents (e.g., organic solvents: methanol, tetrahydrofuran, n-heptane, acetic acid, benzene, ethanol, acetone, etc., and medium- and low-temperature coal tar or its fractions) on coal pyrolysis behavior, combined with the addition of catalysts (e.g., metal ions such as Na, K, Li, Ca, Mg, Zn, Mn, Fe, Cu, Co, Cr, Ni, Al, etc.) to investigate the synergistic mechanism between coal, oil, and catalyst. Furthermore, the influence of different pyrolysis conditions (e.g., pyrolysis temperature, catalyst dosage and particle size, pressure, atmosphere, etc.) on the yield and composition of coal pyrolysis products was studied, thus constructing a method that can effectively regulate the coal pyrolysis process and achieve targeted enrichment and quality optimization of target products.

[0048] The method of this invention starts from "source control of coal pyrolysis" and achieves synchronous, adjustable and significant improvement in the yield and composition of pyrolysis products through the synergistic co-pyrolysis of coal-oil-catalyst. Moreover, the process is simpler, applicable to a wider range of coal and oil types, and the tar increase is greater, thus possessing stronger industrial scale-up potential.

[0049] The following embodiments provide a detailed description of the method for controlling the yield and composition of coal pyrolysis products provided by the present invention.

[0050] Example 1 A method for controlling the yield and composition of coal pyrolysis products involves using Shendong low-rank bituminous coal (SD) as raw material. Coal samples with a particle size <0.075mm and a moisture content ≤6% are obtained through crushing and screening. SD is then subjected to HCl / HF stepwise deashing treatment to prepare deashed coal (SD-DE). The following method is used to control the yield and composition of coal pyrolysis products on the deashed coal: (1) Coal and oil pyrolysis treatment SD-DE-ME and SD-DE-TH feedstocks were prepared by mixing methanol (ME) and tetrahydrofuran (TH) as oils in a 4:1 (mass ratio) ratio with SD-DE. SD-DE-TM feedstock was prepared by mixing methanol (ME) and tetrahydrofuran (TH) as oils in a 1:7 (volume ratio) ratio with SD-DE in a 4:1 (mass ratio) ratio.

[0051] After introducing N2 as a pyrolysis carrier gas, the above raw materials were preheated to 150°C and then pyrolyzed at 650°C and atmospheric pressure using a Gagkin distiller. The pyrolysis volatiles were collected at the bottom via a condenser to obtain coal tar, while pyrolysis gas was obtained at the top. The semi-coke remaining inside the reactor was directly obtained, yielding the three-phase yield of the raw material pyrolysis. As shown in Table 1, the SD-DE-TM showed the highest tar yield, at 9.40%.

[0052] The obtained coal tar was analyzed by gas chromatography-mass spectrometry, and its component content information was obtained by area normalization method. The contents of aromatic hydrocarbons (benzene, toluene, xylene and naphthalene, etc.) and acidic compounds (phenol, cresol, xylenol and catechol, etc.) are shown in Table 2. The aromatic hydrocarbon content in the pyrolysis tar of SD-DE-TM was 42.02%, and the acidic compound content was 32.01%.

[0053] (2) Coal and catalyst pyrolysis treatment Using LiCl, CaCl2, MnCl2, CuCl2, and CoCl2 as solutes, deashed coal (SD-DE) was loaded with metal ions to prepare Li-loaded coal. + Ca 2+ Mn 2+ Cu 2+ With Co 2+ The coal samples containing metal ions (SD-DE-Li, SD-DE-Ca, SD-DE-Mn, SD-DE-Cu, and SD-DE-Co) are as follows: SD-DE was impregnated in an aqueous solution containing a certain amount of the above-mentioned metal ions and 20% methanol at a certain ratio. The concentration of metal ions in the aqueous solution was 0.002 g / mL, the ratio of aqueous solution to coal was 4 mL : 1 g, the metal loading was 0.8% of the coal mass, and the metal salt particle size was 20 µm. After stirring and loading for 2 min, the solvent was evaporated and dried until the sample reached constant weight to obtain a coal sample loaded with metal ions.

[0054] After introducing N2 as the pyrolysis carrier gas, the coal sample loaded with metal ions was preheated at 150 °C and then pyrolyzed using a Gagkin distiller at 650 °C and atmospheric pressure. The pyrolysis volatiles were collected at the bottom of the reactor after passing through a condenser to obtain coal tar, while pyrolysis gas was obtained at the top. The semi-coke remaining inside the reactor was directly obtained to obtain the three-phase yield of the raw material pyrolysis. Among them, SD-DE-Cu was the best, with a pyrolysis tar yield of 9.51%.

[0055] The obtained coal tar was analyzed by gas chromatography-mass spectrometry (GC-MS), and its component content information was obtained by area normalization. The effects of SD-DE, SD-DE-Li, SD-DE-Ca, SD-DE-Mn, SD-DE-Cu, and SD-DE-Co on the content of different groups of components in the obtained coal tar were analyzed. The loaded metals all favored the formation of aromatics, with SD-DE-Ca showing the most significant effect.

[0056] (3) Pyrolysis of coal, oil and catalyst Using a mixed solvent of CH3OH and THF as oil, and LiCl, CaCl2, MnCl2, CuCl2, and CoCl2 as solutes, deashed coal (SD-DE) was swollen and simultaneously loaded with metal ions to prepare a CH3OH+THF mixed solvent swollen and simultaneously loaded LiCl metal ions. + Ca 2+ Mn 2+ Cu 2+ With Co 2+ The coal samples containing metal ions (SD-DE-TM-Li, SD-DE-TM-Ca, SD-DE-TM-Mn, SD-DE-TM-Cu, and SD-DE-TM-Co) are as follows: SD-DE were impregnated separately in a CH3OH+THF mixed solution containing the above-mentioned single metal ions. The concentration of the metal ions in the mixed solution was 0.002 g / mL, the volume ratio of CH3OH to THF was 1:7, the ratio of oil to coal was 4 mL:1 g, the metal loading was 0.8% of the coal mass, and the metal salt particle size was 20 µm, thus obtaining oil-loaded metal ion coal raw material.

[0057] After introducing N2 as a pyrolysis carrier gas, the oil-loaded metal ion coal feedstock was preheated at 150 °C and then pyrolyzed at 650 °C under atmospheric pressure using a Gagkin distiller. The pyrolysis volatiles were collected at the bottom of the reactor via a condenser to obtain coal tar, while pyrolysis gas was obtained at the top. The semi-coke remaining inside the reactor was directly collected, yielding the three-phase yield of the feedstock pyrolysis. As shown in Table 1, SD-DE-TM-Co had the highest tar yield of 11.60%; as shown in Table 2, SD-DE-TM-Mn had the highest aromatic hydrocarbon content in its pyrolysis tar, at 53.46%.

[0058] Example 2 A method for controlling the yield and composition of coal pyrolysis products involves using Shendong low-rank bituminous coal (SD) as raw material. After crushing, grinding, and sieving, coal samples with a mesh size of less than 30 mesh (<0.5 mm) and a moisture content ≤6% are obtained. Microscopic components of the SD are separated by flotation-sinking method (density liquid-ZnCl2 solution) to obtain vitrinite (V) enriched coal samples. The V samples are then subjected to HCl / HF stepwise deashing treatment to prepare deashed vitrinite (VD). The following method is used to control the yield and composition of coal pyrolysis products from the deashed vitrinite enriched coal samples: (1) Coal and oil pyrolysis treatment VDS-n-heptane, VDS-acetic acid, VDS-benzene, VDS-ethanol, VDS-THF, and VDS-acetone raw materials were prepared by mixing VDS with n-heptane, acetic acid, benzene, ethanol, THF, and acetone in a 4:1 (mass ratio) ratio.

[0059] After introducing N2 as a pyrolysis carrier gas, the above raw materials were preheated to 150 °C and then pyrolyzed in an infrared furnace at 650 °C and atmospheric pressure. The pyrolysis volatiles were collected at the bottom via a condenser to obtain coal tar, while pyrolysis gas was obtained at the top. The semi-coke remaining inside the reactor was directly obtained, yielding the three-phase yield of the raw materials. The pyrolysis tar yielded the highest value (22.82%) for VDS-acetone. The pyrolysis tar for VDS-acetic acid had the highest BTXN content (17.53%), while the pyrolysis tar for VDS-THF had the highest PCXC content (20.99%).

[0060] (2) Coal and catalyst pyrolysis treatment Using NaCH3COO, KCH3COO, Ca(CH3COO)2, Mg(CH3COO)2, Mn(CH3COO)2, Co(CH3COO)2, Ni(CH3COO)2, Cu(CH3COO)2, Zn(CH3COO)2, Cr(CH3COO)3, Fe(CH3COO)3, and Al(CH3COO)3 as solutes to load metal ions onto deashed vitrinite (VD) groups, Na-loaded metal ions were prepared. + K + Ca 2+ Mg 2+ Mn 2+ Co 2+ Ni 2+ Cu 2+ Zn 2+ Cr 3+ Fe 3+ And Al 3+The coal samples containing metal ions (VD-Na, VD-K, VD-Ca, VD-Mg, VD-Mn, VD-Co, VD-Ni, VD-Cu, VD-Zn, VD-Cr, VD-Fe, and VD-Al) are as follows: VD was mixed with an aqueous solution containing 20% ​​methanol containing a certain amount of metal ions. The concentration of metal ions in the aqueous solution was 0.00125 g / mL. The ratio of aqueous solution to coal was 4 mL: 1 g. The metal loading was 0.5% of the coal mass. The metal salt particle size was 20 µm. The solution containing the ion-exchanged coal sample was then filtered, washed until neutral, and dried until the sample reached constant weight to obtain a metal ion-loaded coal sample.

[0061] After introducing N2 as a pyrolysis carrier gas, the above raw materials are preheated to 150 °C and then pyrolyzed in an infrared heating furnace at 650 °C and atmospheric pressure. The pyrolysis volatiles are collected at the bottom of the reactor after passing through a condenser to obtain coal tar, and pyrolysis gas is obtained at the top. The semi-coke remaining inside the reactor is directly obtained to obtain the three-phase yield of the raw material pyrolysis. Among them, the pyrolysis tar yield of VD-Al is the highest, at 28.01%.

[0062] The obtained coal tar was analyzed using gas chromatography-mass spectrometry (GC-MS). The component content information was obtained using the area normalization method. The distribution of different group components in the obtained VD, VD-Na, VD-K, VD-Ca, VD-Mg, VD-Mn, VD-Co, VD-Ni, VD-Cu, VD-Zn, VD-Cr, VD-Fe, and VD-Al coal tars was analyzed. Among them, the VD-Mn pyrolysis tar had the highest aromatic hydrocarbon content, at 30.98%.

[0063] (3) Pyrolysis of coal, oil and catalyst A mixture of acetone, THF, ethanol, benzene, acetic acid, and n-heptane was selected as the solvent for oil. CH3COONa, CH3COOK, Ca(CH3COO)2, Mg(CH3COO)2, Mn(CH3COO)2, Co(CH3COO)2, Ni(CH3COO)2, Cu(CH3COO)2, Zn(CH3COO)2, Cr(CH3COO)3, Fe(CH3COO)3, and Al(CH3COO)3 were used as solutes to swell and simultaneously load metal ions onto deashed vitrinite (VD) coal samples (VDS-Na, VDS-K, VDS-Ca, VDS-Mg, VDS-Mn, VDS-Co, VDS-Ni, VDS-Cu, VDS-Zn, VDS-Cr, VDS-Fe, and VDS-Al) were prepared.

[0064] VD was mixed into solutions containing the aforementioned single metal ions and mixed solvents. The concentration of the metal ion in the mixed solution was 0.00125 g / mL. The ratio of oil to coal was 4 mL : 1 g. The volume ratio of acetone, THF, ethanol, benzene, acetic acid, and n-heptane was 0.10 : 0.32 : 21.68 : 51.29 : 1.29 : 25.33. The metal loading was 0.5% of the coal mass, and the metal salt particle size was 20 µm. Oil-loaded metal ion coal feedstock was obtained.

[0065] After introducing N2 as the pyrolysis carrier gas, the oil-loaded metal ion coal feedstock was preheated at 150 °C and then pyrolyzed in an infrared furnace at 650 °C and atmospheric pressure. The pyrolysis volatiles were collected at the bottom via a condenser to obtain coal tar, while pyrolysis gas was obtained at the top. The semi-coke remaining inside the reactor was directly collected, and the distribution of the pyrolysis products was determined. As shown in Table 1, the VD-Al pyrolysis tar yield was the highest at 28.01%; as shown in Table 2, the VDS-Fe pyrolysis tar had the highest aromatic hydrocarbon content at 36.73%.

[0066] Example 3 A method for controlling the yield and composition of coal pyrolysis products involves using Shendong low-rank bituminous coal (SD) as raw material. The coal sample is dried, crushed, sieved, and then crushed and sieved again to obtain a particle size <0.2 mm and a moisture content ≤6%. Microscopic components are separated from the SD using a flotation-sinking method (density liquid-ZnCl2 solution) to obtain a vitrinite (V) enriched coal sample. The V sample is then subjected to HCl / HF stepwise deashing treatment to prepare deashed vitrinite (VD). The yield and composition of coal pyrolysis products are controlled using the following method on the deashed vitrinite enriched coal sample: (1) Coal and oil pyrolysis treatment VDS-n-heptane, VDS-acetic acid, VDS-benzene, VDS-ethanol, VDS-THF and VDS-acetone raw materials were prepared by mixing VDS with n-heptane, acetic acid, benzene, ethanol, tetrahydrofuran (THF) and acetone as oils in a ratio of 4:1 (mass ratio) and stirring and swelling at room temperature for 24 h.

[0067] After introducing N2 as a pyrolysis carrier gas, the above raw materials are preheated to 150 °C and then pyrolyzed in an infrared heating furnace at 650 °C and atmospheric pressure. The pyrolysis volatiles are collected at the bottom of the reactor via a condenser to obtain coal tar, while pyrolysis gas is obtained at the top, directly extracting the semi-coke remaining inside the reactor.

[0068] (2) Coal and catalyst pyrolysis treatment Using NaNO3, KNO3, Ca(NO3)2, Mg(NO3)2, Mn(NO3)2, Co(NO3)2, Ni(NO3)2, Cu(NO3)2, Zn(NO3)2, Cr(NO3)3, Fe(NO3)3, and Al(NO3)3 as solutes, metal ions were loaded onto deashed vitrinite (VD) to prepare Na-loaded metal ions. + K + Ca 2+ Mg 2+ Mn 2+ Co 2+ Ni 2+ Cu 2+ Zn 2+ Cr 3+ Fe 3+ And Al 3+ The coal samples containing metal ions (VD-Na, VD-K, VD-Ca, VD-Mg, VD-Mn, VD-Co, VD-Ni, VD-Cu, VD-Zn, VD-Cr, VD-Fe, and VD-Al) are as follows: VD was mixed with an aqueous solution containing 20% ​​methanol containing a certain amount of metal ions. The concentration of metal ions in the aqueous solution was 0.00125 g / mL. The ratio of aqueous solution to coal was 4 mL: 1 g. The metal loading was 0.5% of the coal mass. The metal salt particle size was 20 µm. After stirring and loading for 6 h, the sample was dried to constant weight to obtain a coal sample loaded with metal ions.

[0069] After introducing N2 as a pyrolysis carrier gas, the above raw materials were preheated to 150 °C and then pyrolyzed in an infrared furnace at 650 °C and atmospheric pressure. The pyrolysis volatiles were collected at the bottom via a condenser to obtain coal tar, while pyrolysis gas was obtained at the top, directly extracting the semi-coke remaining inside the reactor. The three-phase yields of the raw material pyrolysis were obtained, with VD-Fe pyrolysis tar showing the highest yield at 19.84%. VD-Mn pyrolysis tar had the highest alkane content at 27.43%.

[0070] (3) Pyrolysis of coal, oil and catalyst A mixed solvent of acetone, THF, ethanol, benzene, acetic acid, and n-heptane was selected as the oil. NaNO3, KNO3, Ca(NO3)2, Mg(NO3)2, Mn(NO3)2, Co(NO3)2, Ni(NO3)2, Cu(NO3)2, Zn(NO3)2, Cr(NO3)2, Fe(NO3)2, and Al(NO3)3 were used as solutes to simultaneously load metal ions onto deashed vitrinite (VD) coal samples (VDS-Na, VDS-K, VDS-Ca, VDS-Mg, VDS-Mn, VDS-Co, VDS-Ni, VDS-Cu, VDS-Zn, VDS-Cr, VDS-Fe, and VDS-Al) were prepared using the mixed solvent for swelling. The details are as follows: VD was mixed into a mixed solvent solution containing the aforementioned single metal ion. The concentration of the metal ion in the mixed solution was 0.00125 g / mL. The ratio of oil to coal was 4 mL : 1 g. The volume ratio of acetone, THF, ethanol, benzene, acetic acid, and n-heptane was 0.10 : 0.32 : 21.68 : 51.29 : 1.29 : 25.33. The metal loading was 0.5% of the coal mass, and the metal salt particle size was 20 µm. Oil-loaded metal ion coal feedstock was obtained.

[0071] After introducing N2 as a pyrolysis carrier gas, the above raw materials were preheated to 150 °C and then pyrolyzed in an infrared furnace at 650 °C and atmospheric pressure. The pyrolysis volatiles were collected at the bottom via a condenser to obtain coal tar, while pyrolysis gas was obtained at the top, directly extracting the semi-coke remaining inside the reactor. The distribution of the pyrolysis products was obtained. As shown in Table 1, the VD-Al pyrolysis tar yield was the highest, at 23.43%. As shown in Table 2, the VDS-Cu pyrolysis tar had the highest aromatic hydrocarbon content, at 39.24%.

[0072] Example 4 A method for controlling the yield and composition of coal pyrolysis products involves using Shendong low-rank bituminous coal (SD) as raw material. The coal is dried, crushed, screened, and then crushed and screened again to obtain a coal sample with a particle size <0.2 mm and a moisture content ≤6%. The SD is then subjected to HCl / HF stepwise deashing treatment to prepare deashed raw coal (RD). The yield and composition of the coal pyrolysis products are then controlled by coal-oil pyrolysis treatment of the deashed raw coal, as detailed below: RD-n-heptane, RD-acetic acid, RD-benzene, RD-ethanol, RD-THF and RD-acetone raw materials were prepared by mixing n-heptane, acetic acid, benzene, ethanol, tetrahydrofuran (THF) and acetone as oils with RD at a ratio of 4:1 (mass ratio) and stirring at 150°C for 1 h.

[0073] After introducing N2 as a pyrolysis carrier gas, the above raw materials are preheated to 150 °C and then pyrolyzed in an infrared furnace at 650 °C and atmospheric pressure. The pyrolysis volatiles are collected at the bottom via a condenser to obtain coal tar, while pyrolysis gas is obtained at the top, directly extracting the semi-coke remaining inside the reactor. The three-phase yield of the raw materials is obtained, such as... Figure 1 As shown in Table 1, RD-THF had the highest pyrolysis tar yield, at 24.37%.

[0074] The obtained coal tar was analyzed using gas chromatography-mass spectrometry (GC-MS), and its component content information was obtained using the area normalization method. The content of group components is shown in the figure below. Figure 2 As shown in Table 2, the pyrolysis tar of RD-acetone has the highest aromatic content, at 36.14%.

[0075] Example 5 A method for controlling the yield and composition of coal pyrolysis products involves using Shendong low-rank bituminous coal (SD) as raw material. The coal sample is dried, crushed, screened, and then crushed and screened again to obtain a particle size <0.5 mm and a moisture content ≤6%. The SD is then subjected to HCl / HF stepwise deashing treatment to prepare deashed raw coal (RD). The yield and composition of the coal pyrolysis products are then controlled by coal-oil pyrolysis treatment of the deashed raw coal, as detailed below: RD-n-heptane, RD-acetic acid, RD-benzene, RD-ethanol, RD-THF and RD-acetone were prepared by mixing n-heptane, acetic acid, benzene, ethanol, tetrahydrofuran (THF) and acetone as oils with RD in a ratio of 4:1 (mass ratio) and stirring at 200°C for 1 h.

[0076] After introducing N2 as the pyrolysis carrier gas, the above raw materials were preheated to 150 °C and then pyrolyzed in an infrared furnace at 650 °C and atmospheric pressure. The pyrolysis volatiles were collected at the bottom via a condenser to obtain coal tar, and pyrolysis gas was obtained at the top. The semi-coke remaining inside the reactor was directly obtained, yielding the three-phase yield of the raw materials. The pyrolysis tar yield of RD-THF was the highest, at 22.49%; the pyrolysis tar of RD-acetone had the highest aromatic content, at 51.33%. For BTNX in the pyrolysis tar, please refer to [reference needed]. Figure 3 .

[0077] Example 6 A method for controlling the yield and composition of coal pyrolysis products involves using Shendong low-rank bituminous coal (SD) as raw material. The coal is dried, crushed, screened, and then crushed and screened again to obtain a coal sample with a particle size <74μm and a moisture content ≤6%. The SD is then subjected to HCl / HF stepwise deashing treatment to prepare deashed coal (SD-DE). The yield and composition of the coal pyrolysis products are controlled by coal-catalyst pyrolysis treatment, as detailed below: Using NaCH3COO, KCH3COO, Ca(CH3COO)2, Mg(CH3COO)2, Co(CH3COO)2, and Ni(CH3COO)2 as solutes, metal ions were loaded onto deashed coal (SD-DE) to prepare Na-loaded metal ions. + K + Ca 2+ Mg 2+ Co 2+ and Ni 2 + Coal samples containing metal ions (SD-DE-Na, SD-DE-K, SD-DE-Ca, SD-DE-Mg, SD-DE-Co, SD-DE-Ni). SD-DE was mixed with a 20% methanol aqueous solution containing a certain amount of metal ions. The concentration of metal ions in the aqueous solution was 0.00125 g / mL, the ratio of aqueous solution to coal was 4 mL : 1 g, the metal loading was 0.5% of the coal mass, and the metal salt particle size was 20 µm. The mixture was stirred until the pH of the solution was constant (pH 8.3 was the best). The solution containing the ion-exchanged coal samples was then filtered, washed until neutral, and dried until the sample reached constant weight to obtain the metal ion-loaded coal samples.

[0078] After introducing N2 as a pyrolysis carrier gas, the above raw materials were preheated to 150 °C and then pyrolyzed in an infrared furnace at 650 °C and atmospheric pressure. The pyrolysis volatiles were collected at the bottom of the reactor after passing through a condenser to obtain coal tar, and pyrolysis gas was obtained at the top. The semi-coke remaining inside the reactor was directly obtained to obtain the three-phase yield of the raw material pyrolysis. As shown in Table 1, the pyrolysis tar yield of SD-DE-Mg was the highest, at 17.74%.

[0079] The obtained coal tar was analyzed by gas chromatography-mass spectrometry, and the component content information was obtained by area normalization method. As shown in Table 2, the pyrolysis tar of SD-DE-Co had the highest aromatic content, at 30.07%.

[0080] Example 7 A method for controlling the yield and composition of coal pyrolysis products is basically the same as in Example 6, except that: Na2SO4, K2SO4, CaSO4, MgSO4, CoSO4, and NiSO4 are used as solutes to load metal ions onto deashed coal (SD-DE), thereby preparing Na-loaded products. + K + Ca 2+ Mg 2+ Co 2+ and Ni 2+For coal samples containing metal ions (SD-DE-Na, SD-DE-K, SD-DE-Ca, SD-DE-Mg, SD-DE-Co, SD-DE-Ni), the remaining steps are the same as in Example 6.

[0081] The three-phase yields of the feedstock pyrolysis were obtained, as shown in Table 1. The pyrolysis tar yield of SD-DE-Mg was the highest, at 14.69%. The pyrolysis tar of SD-DE-K had the highest contents of aromatic hydrocarbons and acidic compounds, at 30.09% and 16.87%, respectively.

[0082] Example 8 A method for controlling the yield and composition of coal pyrolysis products is basically the same as in Example 6, except that: Na3PO4, K3PO4, Ca3(PO4)2, Mg3(PO4)2, Co3(PO4)2, and Ni3(PO4)2 are used as solutes to load metal ions onto deashed coal (SD-DE), thereby preparing Na-loaded products. + K + Ca 2+ Mg 2+ Co 2+ and Ni 2+ For coal samples containing metal ions (SD-DE-Na, SD-DE-K, SD-DE-Ca, SD-DE-Mg, SD-DE-Co, SD-DE-Ni), the remaining steps are the same as in Example 6.

[0083] The three-phase yields of the feedstock pyrolysis were obtained, as shown in Table 1. The pyrolysis tar yield of SD-DE-Mg was the highest, at 14.57%. The obtained coal tar was analyzed by gas chromatography-mass spectrometry, and its component content information was obtained by area normalization method. Among them, the pyrolysis tar of SD-DE-Co had the highest aromatic content, at 30.15%.

[0084] Example 9 A method for controlling the yield and composition of coal pyrolysis products is basically the same as in Example 6, except that: Na2S, K2S, CaS, MgS, CoS, and NiS are used as solutes to load metal ions onto deashed coal (SD-DE), respectively, to prepare Na-loaded products. + K + Ca 2+ Mg 2+ Co 2+ and Ni 2+ For coal samples containing metal ions (SD-DE-Na, SD-DE-K, SD-DE-Ca, SD-DE-Mg, SD-DE-Co, SD-DE-Ni), the remaining steps are the same as in Example 6.

[0085] The three-phase yields of the feedstock pyrolysis were obtained, as shown in Table 1. The pyrolysis tar yield of SD-DE-Mg was the highest, at 14.49%.

[0086] The obtained coal tar was analyzed by gas chromatography-mass spectrometry, and the component content information was obtained by area normalization method. As shown in Table 2, the aromatic content of SD-DE-Co pyrolysis tar was the highest, at 30.02%.

[0087] Example 10 A method for controlling the yield and composition of coal pyrolysis products involves using Shendong low-rank bituminous coal (SD) as raw material. The coal sample is crushed, ground, sieved, and dried to obtain a mesh size of less than 350 mesh (43 μm) and a moisture content ≤6%. The yield and composition of the coal pyrolysis products are controlled by coal-oil pyrolysis treatment of the SD sample, as detailed below: Using medium-low temperature coal tar heavy oil (HCT) from a certain region in northern Shaanxi as the oil, kerosene slurry S5H5, prepared by mixing SD and HCT at a mass ratio of 5:5, was used as the pyrolysis feedstock.

[0088] After introducing N2 as the pyrolysis carrier gas, the kerosene slurry S5H5 was preheated at 150 °C and then pyrolyzed in an infrared heating furnace reactor at atmospheric pressure at 550 °C and 650 °C, respectively. The pyrolysis volatiles were collected at the bottom via a condenser to obtain coal tar, while pyrolysis gas was obtained at the top. The semi-coke remaining inside the reactor was directly obtained. The three-phase yields of the raw materials at different temperatures were obtained, as shown in Table 1. The highest tar yield (51.03%) was achieved when the kerosene slurry S5H5 was pyrolyzed at 550 °C. As shown in Table 2, the aromatic hydrocarbon content in the pyrolysis tar of kerosene slurry S5H5 was 18.04%.

[0089] Example 11 A method for controlling the yield and composition of coal pyrolysis products is basically the same as that in Example 10, except that the pyrolysis conditions are at atmospheric pressure, and the above raw materials are pyrolyzed at 200℃, 300℃, 400℃, 500℃, 600℃, 700℃ and 800℃ respectively, and the remaining steps are the same as in Example 10.

[0090] To obtain the three-phase yields of the pyrolysis of the raw materials at different temperatures, see [reference needed]. Figure 4 As temperature increases, tar yield first increases and then decreases, and the content of acidic compounds in the tar decreases significantly (see [reference]). Figure 5 As shown in Table 1, the pyrolysis tar yield at S5H5-800℃ was the lowest, at 41.37%. As shown in Table 2, the acid compound content in the pyrolysis tar of kerosene slurry at S5H5-800℃ was 16.64%.

[0091] Example 12 A method for controlling the yield and composition of coal pyrolysis products is basically the same as that in Example 10, except that the pyrolysis conditions are 650 °C, and the above raw materials are pyrolyzed at atmospheric pressure (101.32 kPa), 80.32 kPa, and 60.32 kPa respectively. The remaining steps are the same as in Example 10.

[0092] The three-phase yields of the raw materials under different pressures were obtained, as shown in Table 1. As the pressure increased, the tar yield decreased and the heavy components in the tar increased. The pyrolysis tar yield at S5H5-60.32 kPa had the highest yield of 52.19%. As shown in Table 2, the aromatic hydrocarbon content in the tar at S5H5-60.32 kPa was 23.98%.

[0093] Example 13 A method for controlling the yield and composition of coal pyrolysis products is basically the same as that in Example 10, except that the pyrolysis conditions are 650 °C, and the above raw materials are pyrolyzed at 2 MPa, 2.2 MPa and 2.4 MPa respectively. The remaining steps are the same as in Example 10.

[0094] The three-phase yields of the raw materials under different pressures were obtained, as shown in Table 1. The tar yield decreased with increasing pressure, and the acidic compound content in the tar decreased significantly (see Table 1). Figure 6 Among them, the pyrolysis tar yield at S5H5-2.4kPa was the lowest, at 39.74%; as shown in Table 2, the acid compound content in the tar at S5H5-60.32kPa was 17.32%.

[0095] Example 14 A method for controlling the yield and composition of coal pyrolysis products is basically the same as that in Example 10, except that the pyrolysis carrier gases used are N2, CO2, CO, H2, CH4, and He, respectively, and the pyrolysis is carried out at 650 °C under normal pressure. The remaining steps are the same as in Example 10.

[0096] The three-phase yields of the raw materials under different carrier gases were obtained, as shown in Table 1. The pyrolysis tar yield was the highest under H2 atmosphere, at 53.80%. As shown in Table 2, the tar under H2 atmosphere had the highest acid compounds content, at 27.60%.

[0097] Example 15 A method for controlling the yield and composition of coal pyrolysis products is basically the same as the coal and oil pyrolysis treatment in Example 1, except that: THF (THF8), ethanol (alcohol8), benzene (benzene8), acetic acid (acid8), acetone (ketone8), and n-heptane were selected as reference oils (single oil solvents). Seven groups of mixed solvents with different volume ratios were designed as oils (THF4.5 group: THF:ethanol:benzene:acetic acid:acetone:n-heptane = 4.5 : 0.7 : 0.7 : 0.7 : 0.7 : 0.7; alcohol4.5 group: THF:ethanol:benzene:acetic acid:acetone:n-heptane = 0.7 : 4.5 : 0.7 : 0.7 : 0.7 : 0.7; benzene4.5 group: THF:ethanol:benzene:acetic acid:acetone:n-heptane = 0.7 : 0.7 : 4.5 : 0.7 : 0.7). The mixing ratio for the 4.5 groups (acids, ethanol, benzene, acetic acid, acetone, n-heptane) is THF:ethanol:benzene:acetic acid:acetone:n-heptane = 0.7:0.7:0.7:4.5:0.7:0.7; the mixing ratio for the 4.5 groups (ketones, ethanol, benzene, acetic acid, acetone, n-heptane) is THF:ethanol:benzene:acetic acid:acetone:n-heptane = 0.7:0.7:0.7:0.7:4.5:0.7; the mixing ratio for the 4.5 groups (alkanes, ethanol, benzene, acetic acid, acetone, n-heptane) is THF:ethanol:benzene:acetic acid:acetone:n-heptane = 0.7:1.3:1.3:1.3:1.3:1.3:1.3:1.3 1.3) SD-DE was mixed into a total of 8 mL of base oil and mixed oil, respectively, with an oil to coal ratio of 4 mL : 1 g, to obtain kerosene slurry raw material. The remaining steps were the same as the coal and oil pyrolysis treatment in Example 1.

[0098] The three-phase yields of the feedstock pyrolysis were obtained, as shown in Table 1. The pyrolysis tar yield of SD-DE-benzene 4.5 was the highest, at 20.08%.

[0099] Example 16 A method for controlling the yield and composition of coal pyrolysis products is basically the same as in Example 10, except that: the yield and composition of coal pyrolysis products are controlled by pyrolysis treatment of coal, oil, and catalyst. A kerosene slurry S5H5, prepared by mixing SD and HCT at a mass ratio of 5:5, is prepared using Ni(NO3)2 as a solute (added at amounts of 0.1%, 0.5%, and 0.9% of the mass of SD, with a particle size of 20µm). After stirring and loading for 3 minutes, different Ni-loaded products are obtained. 2+ The kerosene slurry feedstock containing metal ions (S5H5-Ni) was used as the pyrolysis feedstock, and the remaining steps were the same as in Example 10.

[0100] The three-phase yields of the feedstock pyrolysis were obtained, as shown in Table 1. The S5H5-0.9%Ni pyrolysis tar had the highest yield of 40.84%, while the S5H5-0.1%Ni pyrolysis tar had the highest aromatic content of 32.15% (see Table 2).

[0101] Example 17 A method for controlling the yield and composition of coal pyrolysis products is basically the same as that in Example 14, except that the amount of Ni(NO3)2 added is 0.9% of the mass of SD, and the particle sizes are 20µm, 45µm and 70µm, respectively, to prepare Ni with different particle sizes. 2+ Kerosene slurry feedstock containing metal ions (S5H5-Ni).

[0102] After introducing N2 as a pyrolysis carrier gas, the above raw materials were preheated to 150 °C and then pyrolyzed in an infrared furnace at 650 °C and atmospheric pressure. The pyrolysis volatiles were collected at the bottom via a condenser to obtain coal tar, while pyrolysis gas was obtained at the top, directly extracting the semi-coke remaining inside the reactor. The three-phase yields of the raw material pyrolysis were obtained, as shown in Table 1. The S5H5-70µmNi pyrolysis tar yield was the lowest at 38.14%, as shown in Table 2. Its tar had the highest aromatic hydrocarbon content at 31.89%.

[0103] Example 18 A method for controlling the yield and composition of coal pyrolysis products is basically the same as in Example 10, except that SD and HCT are mixed in mass ratios of 3:7, 4:6, 5:5, and 6:4 to form a kerosene slurry, yielding raw materials S3H7, S4H6, S5H5, and S6H4, respectively. The above raw materials are pyrolyzed using an infrared heating furnace reactor to obtain the theoretical and actual three-phase yields of the pyrolysis. Figure 7 As shown in Table 1, the experimental value of S3H7- showed the highest pyrolysis tar yield, at 64.44%.

[0104] The theoretical value (ES) in each embodiment of the present invention is the average yield of products obtained by pyrolysis of SD and HCT or their fractions alone, as shown in the following formula: Yield ES = α S ·Y S +α T ·Y T In the formula, Yield ES Y represents the theoretical value of the yield of the pyrolysis products; S and Y T α represents the actual yield of the products when SD and HCT or their fractions are pyrolyzed separately; S and α TThese represent the mass percentages of SD and HCT or their fractions in the sample during co-pyrolysis.

[0105] The obtained coal tar was analyzed by gas chromatography-mass spectrometry (GC-MS), and its component content information was obtained by area normalization. The contents of PCX (phenol, cresol, and xylenol) and aromatic hydrocarbons (1-R, 2-R, 3-R, 4-R) were as follows: Figure 8 As shown.

[0106] The kerosene slurry S5H5, prepared by mixing SD and HCT in a mass ratio of 5:5, contains Fe(NO3)3, Cu(NO3)2, Ni(NO3)2, and (NH4)6Mo7O. 24 Loaded Fe was prepared by stirring and loading the solute (0.9% of the mass of SD, particle size 20µm) for 3 min, respectively. 3+ Cu 2+ Ni 2+ with Mo 6+ The kerosene slurry raw materials S5H5-Fe, S5H5-Cu, S5H5-Ni and S5H5-Mo containing metal ions were used as pyrolysis raw materials, and the pyrolysis steps were the same as in Example 9.

[0107] The three-phase yields of the feedstock pyrolysis were obtained. The S5H5-Mo pyrolysis semi-coke yield was the highest at 49.67%, and the tar yield was 42.98%. As shown in Table 2, the S5H5-Fe pyrolysis tar had the highest aromatic content at 31.70%.

[0108] Example 19 A method for controlling the yield and composition of coal pyrolysis products, using Shendong low-rank bituminous coal (SD) as raw material, after crushing, grinding, sieving and drying to obtain a coal sample with a mesh size of less than 350 mesh (43 μm) and a moisture content of ≤6%, the method for controlling the yield and composition of coal pyrolysis products is as follows: (1) Coal and oil pyrolysis treatment Using medium-low temperature coal tar (T), T<210℃ distillate oil-light oil (QY), T<210~230℃ distillate oil-phenol oil (FY), T<230~270℃ distillate oil-naphthalene oil (NY), and T<270℃ distillate oil-wash oil (XY) as oils, SD was mixed with T, QY, FY, NY, and XY at a mass ratio of 1:3 to prepare kerosene slurry, and SD-T, SD-QY, SD-FY, SD-NY, and SD-XY raw materials were obtained respectively.

[0109] After introducing N2 as a pyrolysis carrier gas, the above raw materials are preheated to 150 °C and then pyrolyzed in an infrared furnace at 650 °C and 0.08 MPa. The pyrolysis volatiles are collected at the bottom via a condenser to obtain coal tar, while pyrolysis gas is obtained at the top. The semi-coke remaining inside the reactor is directly obtained, yielding the theoretical and actual three-phase yields of the raw material pyrolysis. Figure 9 As shown in Table 1, the pyrolysis tar yield of the SD-NY experimental value was 73.99%.

[0110] (2) Coal and oil pyrolysis treatment with catalyst A Cu-loaded coal sample (SD-Cu) was prepared by solid-solid mixing of Cu(NO3)2 with Shendong low-rank bituminous coal (SD). Specifically, the metal salt was mixed with SD in a grinding mortar (the amount of metal salt added was 0.9% of the coal mass), and ground three times until it adhered to the wall, thus obtaining the metal-loaded coal sample.

[0111] For the metal-supported coal samples prepared above, medium-low temperature coal tar (T), T <210℃ distillate oil-light oil (QY), T 210~230℃ distillate oil-phenol oil (FY), T 230~270℃ distillate oil-naphthalene oil (NY), and T >270℃ distillate oil-wash oil (XY) were selected as oils, and Cu(NO3)2 was used as the solute to carry out oil-solubilized + metal-supported Shendong coal (SD), respectively, to prepare SD-T-Cu, SD-QY-Cu, SD-FY-Cu, SD-NY-Cu, and SD-XY-Cu coal oil slurry raw materials. Specifically, the mass ratio of oil to coal in the preparation was 3:1.

[0112] After introducing N2 as a pyrolysis carrier gas, the above raw materials were preheated to 150 °C and then pyrolyzed in an infrared furnace at 650 °C and 0.08 MPa. The pyrolysis volatiles were collected at the bottom via a condenser to obtain coal tar, while pyrolysis gas was obtained at the top, directly extracting the semi-coke remaining inside the reactor. The three-phase yields of the raw material pyrolysis were obtained, with SD-NY-Cu showing the highest pyrolysis tar yield at 55%. As shown in Table 2, the aromatic hydrocarbon content in the SD-NY-Cu tar was 21.93%.

[0113] The three-phase yields of the pyrolysis products in Examples 1-19 were calculated, and the results are shown in Table 1.

[0114] Table 1. Comparison of three-phase yields of pyrolysis products in Examples 1-19

[0115] Note: SD-DE, VDS, and RD are control groups for coal treated with the same pyrolysis conditions in the corresponding examples.

[0116] As shown in Table 1, the yield of coal pyrolysis products can be effectively improved by pyrolyzing coal and oil (including solvent, coal tar and its fractions), coal and catalyst (including mechanical mixing, ion exchange and impregnation loading methods), and coal mixtures consisting of coal, oil and catalyst in a pyrolysis reactor.

[0117] Longitudinal analysis of individual groups revealed that in Example 1, the coal mixture composed of deashed coal (SD-DE) with methanol (ME), tetrahydrofuran (TH), and ME+TH effectively increased the tar yield by up to 9.40% compared to SD-DE, while also increasing the gas yield by up to 15.92%. The coal mixture composed of SD-DE with ME+TH and Co showed even greater increases in coal tar yield (11.60%) and gas yield (17.65%). Examples 2 and 3, using deashed vitrinite (VD) with oil (a mixture of acetone, THF, ethanol, benzene, acetic acid, and n-heptane) and catalysts (Cr and Mn), significantly increased the coal tar yield compared to the VDS mixture composed of VD and oil (a mixture of acetone, THF, ethanol, benzene, acetic acid, and n-heptane), with increases of 9.62% and 5.29%, respectively. Examples 4 and 5, using deashed raw coal (RD) and tetrahydrofuran (THF) to form coal mixtures, both increased coal tar yield and pyrolysis gas yield compared to RD, with Example 4 showing the largest increase, reaching 3.51% and 4.54%, respectively. Examples 6-9, using deashed coal (SD-DE) and acetate, sulfate, phosphate, and sulfide metal salts to form coal mixtures, also increased coal tar and pyrolysis gas yield compared to SD-DE (although the types of metal salts differed, the differences were not significant). Examples 10-17, using Shendong low-rank bituminous coal (SD) and coal tar (HCT) 5: 5. A kerosene mixture S5H5 was formed by mixing kerosene under different temperatures (200℃, 300℃, 400℃, 500℃, 550℃, 600℃, 650℃, 700℃, and 800℃), pressures (101.32kPa, 80.32kPa, 60.32kPa, 2MPa, 2.2MPa, and 2.4MPa), carrier gases (N2, CO2, CO, H2, CH4, He), oil mixing ratios, and catalyst / metal salt loading / addition amounts (SD quality). Pyrolysis was performed at concentrations of 0.1%, 0.5%, and 0.9% (by weight) and catalyst / metal salt particle sizes of 20µm, 45µm, and 70µm. It was found that excessively high temperatures reduced tar yield while increasing pyrolysis gas yield, while pressures below atmospheric pressure promoted tar and pyrolysis gas formation. H2 in the carrier gas had the best effect on promoting tar formation (an increase of 3.84%). Different proportions of mixed solvents effectively promoted tar formation, with higher metal loading or smaller particle sizes having a more significant effect on promoting tar formation. In Example 18, a coal mixture S3H7 was constructed by mixing Shendong low-rank bituminous coal (SD) with coal tar (HCT) at a ratio of 3:7 (mass ratio). The experimental value of S3H7 coal tar yield showed the highest increase compared to the theoretical value, reaching 2.48%. Example 19 describes a coal mixture SD-NY, which is formed by mixing low-rank bituminous coal (SD) and naphthalene oil fraction (NY) from coal tar. The coal-oil mixing ratio is 1:3 (mass ratio). The experimental value of coal tar yield of SD-NY showed the highest increase compared to the theoretical value, reaching 28.16%.A cross-sectional comparison across multiple groups revealed that all 19 examples validated the effectiveness of coal-oil, coal-catalyst, and coal-oil-catalyst mixtures in improving the yield of the target pyrolysis product.

[0118] The relative contents of aromatics and acidic compounds in the coal tar of Examples 1-19 were calculated by GC / MS, and the results are shown in Table 2.

[0119] Table 2 Comparison of relative contents of aromatics and acidic compounds in coal tar from Examples 1-19 by GC / MS ; Note: The “sub-group” in the table represents the group with the highest relative content of aromatics and acidic compounds in each example and is the most representative; “ / ” indicates none. Since the oil used in the coal-oil co-pyrolysis in Example 15 is benzene (aromatic), the estimate of aromatics in the pyrolysis product tar was inaccurate and was not analyzed.

[0120] As shown in Table 2, the composition of coal pyrolysis products can be effectively improved by pyrolyzing coal and oil (including solvent, coal tar and coal tar four-component fractions), coal and catalyst (including mechanical mixing, ion exchange and impregnation loading methods), and coal mixtures consisting of coal, oil and catalyst in a pyrolysis reactor.

[0121] Longitudinal analysis of individual groups revealed that in Example 1, the coal mixture composed of deashed coal (SD-DE) with methanol (ME), tetrahydrofuran (TH), and ME+TH effectively increased the relative content of aromatics and acidic compounds in the coal tar compared to SD-DE, with the highest total relative content reaching 74.03%. The coal mixture composed of SD-DE with ME+TH and Mn showed an even greater increase in the relative content of aromatics and acidic compounds in the coal tar, with a total relative increase of 3.06% compared to SD-DE. Examples 2 and 3, using deashed vitrinite (VD) with oil (a mixture of acetone, THF, ethanol, benzene, acetic acid, and n-heptane) and catalysts (Fe and Cu), significantly increased the relative content of aromatics and acidic compounds in the coal tar compared to the coal mixture VDS composed of VD and oil (a mixture of acetone, THF, ethanol, benzene, acetic acid, and n-heptane), with increases of 7.04% and 6.20% respectively (total relative content of aromatics and acidic compounds). Examples 4 and 5, using deashed raw coal (RD) and acetone to form coal mixtures, both increased the relative content of aromatics and acidic compounds in coal tar compared to RD. Example 4 showed the largest increase, with an 8.93% increase in the relative content of aromatics and a 3.98% increase in the relative content of acidic compounds. Examples 6-9, using deashed coal (SD-DE) and acetate, sulfate, phosphate, and sulfide metal salts to form coal mixtures, also increased the relative content of aromatics in coal tar compared to SD-DE (although the types of metal salts were different, the differences were not significant). Examples 10-17 involved pyrolysis of a kerosene mixture S5H5, constructed from a 5:5 mixture of Shendong low-rank bituminous coal (SD) and coal tar (HCT). The mixture was subjected to various pyrolysis conditions at different temperatures (200℃, 300℃, 400℃, 500℃, 550℃, 600℃, 650℃, 700℃, and 800℃), pressures (101.32 kPa, 80.32 kPa, 60.32 kPa, 2 MPa, 2.2 MPa, and 2.4 MPa), carrier gases (N2, CO2, CO, H2, CH4, He), oil mixing ratios, catalyst / metal salt loading / addition amounts (0.1%, 0.5%, and 0.9% of SD mass), and catalyst / metal salt particle sizes (20 µm, 45 µm, and 70 µm). The results showed that increasing the temperature promoted aromatic hydrocarbon formation (by up to 4.88%) and inhibited the formation of acidic compounds, while lower pressures (0.1 µm and 0.9% of atmospheric pressure) were also effective. MPa) promotes the release of aromatics. H2, as a pyrolysis carrier gas, can significantly increase the relative content of aromatics and acidic compounds (up to 10.53% compared to N2 carrier gas). Higher metal loading and smaller metal particle size reduce the content of aromatics and acidic compounds in coal tar. Example 18 uses a mixture of Shendong low-rank bituminous coal (SD), coal tar (HCT), and Fe to form a coal mixture S5H5-Fe with a coal-to-oil mixing ratio of 5:5 (mass ratio). Compared to S5H5 and S5H5-Fe coal tar, this mixture shows an 8.78% increase in the relative content of aromatics.Example 19 involved mixing low-rank bituminous coal (SD) with coal tar light oil fraction (QY) and Cu to form a coal mixture SD-QY-Cu, with a coal-oil mixing ratio of 1:3 (mass ratio). Compared to SD-QY and SD-QY-Cu, this mixture showed the highest increase in the relative content of aromatics and acidic compounds in the coal tar, with a total increase of 6.71%. A cross-sectional comparison across multiple groups revealed that all 19 examples validated the effectiveness of coal-oil, coal-catalyst, and coal-oil-catalyst mixtures in improving the composition of the target pyrolysis products.

[0122] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A method for controlling the yield and composition of coal pyrolysis products, characterized in that, The method includes: A coal mixture consisting of coal and oil, coal and catalyst, or coal, oil and catalyst is used. The coal mixture is pyrolyzed at 300-800°C in a pyrolysis carrier gas atmosphere. The pyrolysis reaction pressure is 0-2 MPa. The pyrolysis volatiles are separated by condensation to obtain coal tar, pyrolysis gas and semi-coke. The coal is lignite, bituminous coal, or a mixture thereof that has been processed to obtain deashed coal or different petrographic components of the coal, wherein the petrographic components include: pithite group, vitrinite group, and inertinite group; The oil is medium-low temperature coal tar heavy oil, medium-low temperature coal tar and its distillate oil, or organic reagents and mixtures thereof with a boiling point of 50~130℃; wherein, the organic reagent is selected from any one or more of methanol, ethanol, tetrahydrofuran, acetone, acetic acid, n-heptane and benzene. The catalyst is any one or more of the following: halides, sulfates, nitrates, phosphates, acetates, oxalates, and sulfides of Al, alkali metals, alkaline earth metals, and transition metals.

2. The method for controlling the yield and composition of coal pyrolysis products according to claim 1, characterized in that, The distillate oil of the medium- and low-temperature coal tar is selected from distillate oil with a boiling point of less than 210℃ - light oil, distillate oil with a boiling point of 210~230℃ - phenol oil, distillate oil with a boiling point of 230~270℃ - naphthalene oil, or distillate oil with a boiling point of greater than 270℃ - wash oil.

3. The method for controlling the yield and composition of coal pyrolysis products according to claim 1, characterized in that, The alkali metal is selected from Na and / or K; the alkaline earth metal is selected from Ca and / or Mg; and the transition metal is selected from any one or more of Zn, Mn, Fe, Cu, Co, Ni, Cr, W, and Mo.

4. The method for controlling the yield and composition of coal pyrolysis products according to claim 1, characterized in that, The coal has a particle size of <0.5mm and a moisture content of ≤10%. The coal is deashed by HCl / HF stepwise deashing treatment to obtain deashed coal, or it is prepared by flotation and sedimentation to separate microscopic components to obtain vitrinite-enriched coal sample, and then deashed by HCl / HF stepwise deashing treatment to obtain deashed vitrinite-enriched coal sample, and then constitutes the coal mixture with oil and / or catalyst.

5. The method for controlling the yield and composition of coal pyrolysis products according to claim 1, characterized in that, The catalyst may be added in any of the following ways: (1) Mechanical mixing of coal and catalyst; (2) Ion exchange between coal and catalyst; (3) Coal and catalyst are loaded by impregnation.

6. The method for controlling the yield and composition of coal pyrolysis products according to claim 5, characterized in that, When the coal mixture consists of coal, oil, and a catalyst, the coal mixture is prepared by impregnating the coal in oil containing the catalyst. When the coal mixture consists of coal and a catalyst, the coal is impregnated in an aqueous solution containing the catalyst, and after loading, the solvent is evaporated and dried to obtain the coal mixture.

7. The method for controlling the yield and composition of coal pyrolysis products according to claim 1, characterized in that, The pyrolysis temperature is 500~800℃, and the pyrolysis reaction pressure is 0.04~0.1MPa.

8. The method for controlling the yield and composition of coal pyrolysis products according to claim 1, characterized in that, In the pyrolysis, the pyrolysis carrier gas is selected from any one or more of N2, He, CH4, H2, CO2 and CO.

9. The method for controlling the yield and composition of coal pyrolysis products according to claim 1, characterized in that, The amount of catalyst added is ≤1% of the coal mass, and the particle size of the catalyst is ≤100µm; Or / and, the mass of the coal accounts for 30 to 50% of the total mass of the coal and oil.

10. The method for controlling the yield and composition of coal pyrolysis products according to any one of claims 1 to 9, characterized in that, The coal and oil, or a mixture thereof and a catalyst, are preheated at 100-200°C, then pyrolyzed, or a portion of the oil is distilled off above its boiling point and returned to the oil source after preheating. The coal tar is then condensed and recovered after pyrolysis, and a portion of the distillate oil with a boiling point ≤200°C is returned as oil for recycling.

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