A composite pyrolysis catalyst for desulfurization before coal combustion and a method for pre-treatment of coal before combustion.

Abstract

This invention discloses a composite pyrolysis catalyst for desulfurization before coal combustion and a method for pre-treatment of coal before combustion. The composite pyrolysis catalyst comprises 2-6 parts of a penetrant, 10-40 parts of a swelling agent, and 2-30 parts of a solvent. The penetrant is selected from one or a combination of two or more components selected from azone, linoleic acid, or octadecyl dimethyl ammonium chloride. The swelling agent is selected from one or a combination of two or more components selected from octadecyl dimethyl ammonium chloride, formamide, polyethylene glycol 600, ethylene glycol butyl ether, isopropanol, and propylene glycol methyl ether. The solvent is selected from one or a combination of two or more components selected from propylene glycol butyl ether, ethylene glycol, cyclohexanol, cyclohexanone, dichloromethane, xylene, methanol, and n-butanol. After treatment with this invention, ultra-low sulfur and low ash ultra-pure coal can be obtained, while ensuring that its physical and chemical properties remain unchanged.

Description

Technical Field

[0001] This invention relates to the field of coal pre-combustion desulfurization technology, and in particular to a composite pyrolysis catalyst for coal pre-combustion desulfurization and a coal pre-treatment method. Background Technology

[0002] Based on the different stages of the desulfurization process, it can be divided into three types of desulfurization methods: pre-combustion, during-combustion, and post-combustion. Pre-combustion desulfurization, under current technological conditions, has a relatively low sulfur removal efficiency, making it difficult to meet environmental protection requirements and production needs, especially for coking coal production. During-combustion desulfurization mainly involves adding a sulfur-fixing agent to the coal. During coal combustion, SO2 and sulfide-containing substances are fixed in the coal slag; this is the commonly used fluidized bed and briquette sulfur fixation technology. Currently, the most effective method for controlling the concentration and total amount of sulfur dioxide emitted into the atmosphere during coal combustion is flue gas desulfurization technology, which is the most widely used. Among current flue gas desulfurization technologies, wet desulfurization technology is the most mature, accounting for 85%-90% of the current installed capacity. This mainly includes wet desulfurization technologies such as CaO, CaCO3, and MgO. Although wet desulfurization technology has an efficiency of over 90%-95%. However, its construction costs are high, its operating costs are high, its maintenance costs are high, and it also generates a large amount of desulfurization gypsum, lime slag, etc., which brings serious environmental problems of secondary pollution.

[0003] Currently, the core technology for pre-combustion desulfurization of coal lies in whether it can achieve coal pyrolysis and sulfur removal without damaging other beneficial components of the coal. Therefore, there is an urgent need to develop a highly efficient, economical, environmentally friendly, clean, and pollution-free pre-combustion pyrolysis desulfurization technology for coal. Summary of the Invention

[0004] To address the problems of existing technologies, this invention provides a composite pyrolysis catalyst for coal pre-combustion desulfurization and a coal pre-treatment method, which can catalyze coal pyrolysis before combustion to achieve desulfurization. The technical solution of this invention is as follows:

[0005] As a first aspect of the present invention, it is to provide a composite pyrolysis catalyst for desulfurization before coal combustion, comprising 2-6 parts of a penetrant, 10-40 parts of a swelling agent and 2-30 parts of a solvent;

[0006] The penetrant is selected from one or a combination of two or more of the following components: azone, linoleic acid, or octadecyl dimethyl ammonium chloride.

[0007] The swelling agent is selected from one or a combination of two or more of the following components: octadecyl dimethyl ammonium chloride, formamide, polyethylene glycol 600, ethylene glycol butyl ether, isopropanol, propylene glycol methyl ether, and 1,2-propanediol.

[0008] The solvent is selected from one or a combination of two or more components selected from propylene glycol butyl ether, ethylene glycol, cyclohexanol, cyclohexanone, dichloromethane, xylene, methanol, and n-butanol.

[0009] Preferably, the composite pyrolysis catalyst for desulfurization before coal combustion comprises propylene glycol butyl ether: 2-6 parts; propylene glycol methyl ether: 5-10 parts; isopropanol: 2-10 parts; formamide: 2-6 parts; linoleic acid: 2-5 parts; and 1,2-propanediol: 5-10 parts.

[0010] Preferably, the composite pyrolysis catalyst for desulfurization before coal combustion comprises ethylene glycol: 15-20 parts; ethylene glycol butyl ether: 10-15 parts; polyethylene glycol 600: 2-5 parts; xylene: 10-15 parts; and n-butanol: 5-10 parts.

[0011] Preferably, the composite cracking catalyst for desulfurization before coal combustion comprises cyclohexanol: 5-10.0 parts; cyclohexanone: 1.5-10 parts; azone: 1-5 parts; dichloromethane: 10-15 parts; methanol: 10-20 parts; and octadecyl dimethyl ammonium chloride: 5-15 parts.

[0012] Preferably, the composite pyrolysis catalyst for desulfurization before coal combustion comprises: propylene glycol butyl ether: 2-6 parts; propylene glycol methyl ether: 5-10 parts; ethylene glycol: 5-20 parts; ethylene glycol butyl ether: 10-15 parts; azone: 1-5 parts; formamide: 2-6 parts; xylene: 5-15 parts; isopropanol: 2.0-10.0 parts; cyclohexanone: 1.5-10 parts; cyclohexanol: 2-10 parts; linoleic acid: 2-5 parts; and dichloromethane: 6-15 parts.

[0013] As a second aspect of the present invention, a method for pre-treatment of coal before combustion is provided, comprising the following steps:

[0014] 1. Material preparation process:

[0015] The coal is washed, sorted, and then crushed.

[0016] 2. Pre-catalytic process section:

[0017] The pulverized coal powder from step 1 is fed into a mixer, and the diluted composite pyrolysis catalyst is sprayed onto the coal powder. After being mixed evenly, it is transferred to a pre-catalytic reactor, heated and stirred at the same time to carry out the pre-catalytic reaction.

[0018] 3. Cracking catalytic reaction and oxidative desulfurization process section:

[0019] After the pre-catalytic reaction is completed, the coal slurry is transported to the cracking catalytic reactor and stirred. The cracking catalytic reaction time is 30-60 minutes. Then, the reaction temperature is increased to 60℃-80℃ and the reaction is carried out for 60-180 minutes. Then, a composite oxidation catalyst is added and the reaction continues.

[0020] 4. Coal washing process:

[0021] After the cracking catalytic reaction and the oxidative desulfurization reaction are completed, the coal slurry is transported to the coal washing machine and washed with water.

[0022] 5. Solid-liquid separation and filtrate recovery process section:

[0023] After the coal washing process is completed, the coal slurry is filtered using a plate and frame filter press to separate the solid and liquid components, thus obtaining the coal after solid-liquid separation.

[0024] 6. Dry the coal after solid-liquid separation to obtain the finished product.

[0025] After undergoing pre-catalysis, cracking catalysis, oxidative desulfurization, washing, and residue recovery, clean coal with a sulfur content of 0.5-0.10 and an ash content of less than 2.5-10.0 can be obtained.

[0026] Preferably, the coal is selected from coking coal, thermal coal, or bituminous coal.

[0027] Preferably, the composite pyrolysis catalyst contains azone, which is dissolved in methanol and then mixed with other components of the composite pyrolysis catalyst.

[0028] Preferably, the composite pyrolysis catalyst comprises octadecyl dimethyl ammonium chloride, which is dissolved in xylene and then mixed with other components of the composite pyrolysis catalyst.

[0029] Preferably, the composite pyrolysis catalyst contains linoleic acid, which is dissolved in isopropanol and then mixed with other components of the composite pyrolysis catalyst.

[0030] Preferably, a coal pretreatment method includes the following steps:

[0031] 1. Material preparation process:

[0032] After the coal is washed by a coal washing machine to remove gangue and inorganic sulfur impurities, it is then conveyed to a hammer mill for crushing. The particle size of the crushed coal should be controlled to be less than 15mm, or 60-80 mesh, thus completing the material preparation process.

[0033] 2. Pre-catalytic process section:

[0034] The pulverized coal powder from step 1 is conveyed to the mixer using a screw conveyor, and a mixture of diluted composite cracking catalyst and water is added simultaneously. The dilution process of the composite cracking catalyst is as follows: the pre-mixed composite cracking catalyst is diluted once with 1 to 10 times its weight of water, and then the diluted material is diluted a second time with 200 times its weight of water using a high-pressure metering pump.

[0035] According to the weight ratio of raw coal to diluted cracking catalyst of 10:1 to 10:8, the diluted cracking catalyst is sprayed into the mixer in one go using a high-pressure metering pump. After being thoroughly mixed, it is then transported to the pre-catalytic reactor by a screw conveyor and heated to 35℃-60℃ at the same time, and the agitator is turned on. The pre-catalytic reaction time is 30 minutes to 60 minutes, after which the process enters the next stage, and the pre-catalytic reaction is completed. The preferred weight ratio of raw coal to diluted cracking catalyst is 10:2.

[0036] 3. Cracking catalytic reaction and oxidative desulfurization process section:

[0037] After the pre-catalytic reaction is completed, the coal slurry is conveyed to the cracking catalytic reactor by a screw conveyor and the reactor agitator is turned on. The cracking catalytic reaction time is required to be 30-60 minutes. Then the reaction temperature is increased to 60℃-80℃. After the reaction time reaches 60-180 minutes, a composite oxidation catalyst of 10-30 parts per thousand of coal weight is added and the reaction is continued for 60 minutes. This completes the cracking catalytic reaction and oxidation desulfurization process.

[0038] 4. Coal washing process:

[0039] After the coal slurry has completed the cracking catalytic reaction and the oxidation desulfurization reaction, it is conveyed to the coal washing machine by a screw conveyor. The sulfides in the coal that have been converted into water-soluble, small-molecule sulfur-containing sulfides during the cracking catalytic reaction and the oxidation desulfurization reaction are washed out to ensure the quality of the coal. This completes the coal washing process.

[0040] 5. Solid-liquid separation and filtrate recovery process section:

[0041] After the coal washing process is completed, the coal slurry is pumped into a plate and frame filter press for solid-liquid separation. The clean coal after solid-liquid separation is conveyed to the next process section 6 by a belt conveyor. The separated filtrate is pumped into a filtrate storage tank for sedimentation and filtration, and then pumped into a composite pyrolysis catalyst storage tank. Before use, after sampling and testing to determine the content of composite pyrolysis catalyst in the filtrate, fresh composite pyrolysis catalyst is added once according to technical specifications for recycling. No composite oxidant needs to be added in this process section (the residual content of composite oxidant is negligible and will not affect the catalytic pyrolysis reaction; composite oxidant should be added according to normal process requirements, so no addition is necessary). The ratio of oxidant to coal remains unchanged during use; thus, solid-liquid separation and filtrate recycling are completed in this process section.

[0042] 6. Residual composite cracking catalyst and oxidant recovery and utilization process section:

[0043] After solid-liquid separation, the coal is conveyed to a rotary drum dryer via a belt conveyor, and the heating system is turned on. The temperature should be controlled between 105℃ and 150℃ to evaporate the residual composite cracking catalyst and oxidant in the coal. The evaporated steam is then pumped into a condenser for condensation and recovery of the composite cracking catalyst and oxidant (because the residual composite oxidant content is small and negligible, it will not affect recycling, so it does not need to be recovered separately to consider the cost of recovery). This completes the process of recovering the residual composite cracking catalyst and oxidant.

[0044] After undergoing pre-catalysis, cracking catalysis, oxidative desulfurization, washing, and residue recovery, clean coal with a sulfur content of 0.5-0.10 and an ash content of less than 2.5-10.0 can be obtained.

[0045] Preferably, the composite oxidation catalyst comprises: sodium peroxide: 1-10 parts; trivalent iron powder: 3-8 parts; octadecanedimethylammonium chloride: 0-20 parts; and triazine: 3-10 parts.

[0046] The reagent provided by this invention has the following function:

[0047] 1. Propylene glycol butyl ether: It is an organic compound, a colorless liquid, easily soluble in water, and has good solubility, especially for oily substances.

[0048] 2. Propylene glycol methyl ether: This is an organic compound, a colorless liquid. It has dispersing properties and can be used as a solvent, dispersant, and diluent. It can also be used as a fuel antifreeze and extractant.

[0049] 3. Ethylene glycol: A simple diol, colorless, odorless, and sweet-tasting liquid. It can be used as a solvent, antifreeze, a phase transfer catalyst, and in cell fusion. It can dissolve inorganic salts such as calcium chloride, zinc chloride, sodium chloride, zinc carbonate, zinc iodide, and potassium hydroxide. Due to its low molecular weight and high reactivity, it can undergo esterification, etherification, alcoholization, oxidation, acetalization, and dehydration reactions.

[0050] 4. Ethylene glycol butyl ether: This is an organic compound, a colorless and transparent liquid, readily soluble in water and mineral oil. It is a high-boiling-point solvent and is also used as a non-reactive diluent, wetting agent, dispersant, extractant, and plasticizer.

[0051] 5. Isopropanol: A colorless, transparent liquid, readily soluble in water, and also soluble in alcohols, ethers, benzene, chloroform, and many other organic solvents. It has a stronger dissolving power for lipophilic substances than ethanol and can be used as a solvent, extractant, dispersant, and antifreeze for alkaloids.

[0052] 6. Formamide: A colorless, transparent, oily liquid with a slight ammonia odor. It is hygroscopic and soluble, and can dissolve casein, glucose, corn starch, lignin, nylon, and certain inorganic salts, such as copper, aluminum, zinc, tin, cobalt, iron, and lead, as well as some carbonic and nitric acids. Formamide can undergo a variety of reactions; in addition to reactions involving three hydrogen atoms, it can also undergo dehydration, decarbonylation, introduction of amino groups, introduction of acyl groups, and cyclization.

[0053] 7. Cycloisools: These are colorless, transparent, oily liquids or white needle-like crystals. They can be used as solvents for metal soaps, oils, esters, and ethers.

[0054] 8. Linoleic acid: A fatty acid that exists in animal and vegetable oils in the form of glycerides. It is the main component of drying and semi-drying oils such as linseed oil and cottonseed oil, which are composed of glycerides. Industrially, it is generally in powder form. It can be used as an emulsifier and surfactant, and its aluminum salts can be used in paints and coatings.

[0055] 9. Cyclohexanone: An organic compound, a saturated cyclic ketone with a carbonyl atom enclosed in a six-ring structure, a colorless and transparent liquid. Slightly soluble in water, soluble in most organic solvents such as alcohols, ethers, and benzene. It can be used as a solvent for fats, waxes, and rubbers. It is a boiling point solvent and is usually prepared into mixed solvents with lower and medium boiling point solvents to obtain suitable evaporation rates and viscosities.

[0056] 10. Dichloromethane: A colorless, transparent liquid with an aromatic odor, slightly soluble in water. Used as a solvent, extractant, mutagen, fire extinguishing agent, deesterifying agent, and intermediate for organic solvents.

[0057] 11. Azone: Colorless to slightly yellow liquid, odorless and tasteless. It can be used as a penetrant, regulator, absorption promoter, wetting agent, etc.

[0058] 12. Polyethylene glycol 600: It is an almost colorless viscous liquid or a translucent waxy soft substance. It has good water solubility and the advantage of being compatible with many organic components. It also has excellent lubricity, moisturizing properties, dispersibility, adhesion, and non-volatility, among other uses.

[0059] 13. Xylene: A colorless, transparent liquid with the characteristic odor of aromatic hydrocarbons. It is used as a solvent, and also as a synthetic monomer compound and a component for high-alkane gasoline.

[0060] 14. 1,2-Propane glycol: Miscible with water, ethanol, and many organic solvents, it is a colorless, viscous liquid under normal conditions, nearly odorless, with a slightly sweet smell. It is widely used as a humectant, antifreeze, lubricant, solvent, softener, and emulsifier.

[0061] I5. Methanol: A colorless and transparent liquid used as a solvent and in organic synthesis. It can dissolve many inorganic salts.

[0062] 16. Octadecyldimethylammonium chloride: A white, waxy substance. It has excellent permeability and antistatic properties, and is compatible with a variety of surfactants or additives, exhibiting significant synergistic effects. It also functions as a softener, leavening agent, and is used for emulsifying asphalt.

[0063] 17. n-Butanol: A colorless and transparent liquid used as a solvent to adjust the evaporation rate and viscosity of solvents.

[0064] 18. Sodium peroxide: An inorganic compound, in the form of yellow powder or granules. It is an alkaline oxidizing agent and solvent, and can also be used as a carbon dioxide absorbent. It has strong oxidizing and reducing properties.

[0065] 19. Trivalent iron powder: This is an inorganic substance, appearing as a reddish-brown powder or granules. When iron reacts with elemental sulfur, copper, hydrochloric acid, etc., it loses two electrons to become +2 valent iron, possessing strong oxidizing properties and acting as a reducing agent capable of both oxidation and reduction.

[0066] 20. Triazine: A pale yellow, transparent, viscous liquid. It has a low molecular weight and can achieve irreversible reactions when removing sulfides. It also degrades thiols, hydrogen sulfide, and organic sulfur compounds.

[0067] The process flow and application method described above in this invention have the following advantages.

[0068] (1) This invention provides a composite pyrolysis catalyst for desulfurization before coal combustion and a coal pre-treatment method. The composite pyrolysis catalyst provided by this invention has strong solubility, permeability and dispersibility, and can catalytically pyrolyze coal at normal temperature and pressure, and then desulfurize it by oxidation. This technology has a good desulfurization effect, and the sulfur content in the coal after treatment is low. At the same time, it can ensure that other physical and chemical properties of coal remain unchanged, and obtain ultra-pure coal with ultra-low sulfur and low ash.

[0069] (2) The composite pyrolysis catalyst of the present invention can also rapidly catalyze pyrolysis reactions without the aid of other physical equipment such as ultrasound or microwave, resulting in high production efficiency and stable product quality.

[0070] (3) This invention uses a neutral pyrolysis catalyst, does not use strong acids, contains no prohibited chemical reagents, is non-corrosive, colorless, odorless, non-toxic, and causes no secondary pollution. The chemical reagents used are readily available and inexpensive.

[0071] (4) The present invention has a short process flow, no expensive equipment investment, easy-to-purchase equipment, low price, low cost, easy maintenance, and is suitable for large-scale coal processing.

[0072] (5) The processing device provided by the present invention occupies a small area and can be installed in a three-dimensional manner. Because the conveying equipment adopts a spiral and closed-loop pipeline conveying and pumping method, it is both dust-free and environmentally friendly. Attached Figure Description

[0073] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0074] Figure 1 This is a structural diagram of the coal combustion pretreatment device provided by the present invention.

[0075] 1-Hammer crusher, 2-Mixer, 3-Pre-catalytic reactor, 4-Crack reactor, 5-Coal washing machine, 6-Plate and frame filter press, 7-Drum dryer, 8-Screw conveyor, 9-Finished product, 10-Installation platform. Detailed Implementation

[0076] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0077] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0078] Example 1: Coal Combustion Pretreatment Device

[0079] like Figure 1 As shown, the device includes a hammer mill 1, a mixer 2, a precatalytic reactor 3, a pyrolysis reactor 4, a coal washing machine 5, a plate and frame filter press 6, a rotary drum dryer 7, and a screw conveyor 8. The processing device provided in this embodiment uses the hammer mill 1 and mixer 2 as the first combination, the precatalytic reactor 3 and pyrolysis reactor 4 as the second combination, the coal washing machine 5 and plate and frame filter press 6 as the third combination, and the rotary drum dryer 7 and screw conveyor 8 as the fourth combination. The first combination, the second combination, and the third combination adopt a three-dimensional upper and lower structure design, and the installation platform 10 with a height of 3 meters is assumed to be made of H steel. The height can also be determined according to the size of the equipment.

[0080] The precatalytic reactor can be a spiral precatalytic reactor, and the pyrolysis reactor can be a spiral pyrolysis reactor.

[0081] On the first combined installation platform, a vertical crusher is installed at the top and a mixer at the bottom. During production, a sealed belt conveyor or a screw conveyor transports the coal to a hammer crusher for crushing. The resulting coal powder flows into the mixer via the natural drop, ensuring thorough mixing. This saves on conveyor equipment and space. On the second combined installation platform, a screw-type precatalytic reactor is installed at the top and a screw-type pyrolysis reactor is installed below. During production, a screw conveyor transports the coal mixed in the mixer to the feed inlet of the screw-type precatalytic reactor for precatalytic reaction. After the precatalytic reaction is complete, the coal flows into the screw-type pyrolysis reactor via the natural drop from the screw-type precatalytic reactor for pyrolysis. On the third combined installation platform, a coal washing machine is installed at the top and a plate and frame filter press is installed below. During production, a screw conveyor connects the discharge outlet of the screw-type pyrolysis reactor to the feed inlet of the coal washing machine, transporting the coal into the washing machine for washing. After coal washing, a slurry pump is used to extract the coal slurry to a plate and frame filter press for dewatering. The fourth assembly does not require an installation platform and is installed parallel to the ground. The dewatered coal powder is conveyed from the outlet of the plate and frame filter press to the inlet of the dryer via a belt conveyor, allowing the coal powder to enter the dryer for drying. The processed coal is then transported to the designated location via a screw conveyor, completing the entire production process.

[0082] The following process is used for coal pretreatment before combustion: the coal is sequentially processed through a hammer mill, mixer, precatalytic reactor, pyrolysis reactor, coal washing machine, plate and frame filter press, and rotary drum dryer to obtain finished product 9.

[0083] Example 2: A composite pyrolysis catalyst and a coal combustion pretreatment method

[0084] Composite pyrolysis catalyst 2-1: Propylene glycol butyl ether: 2.0; Propylene glycol methyl ether: 5.0; Isopropanol: 2.0; 1,2-Propylene glycol: 5.0; Formamide: 6.0; Linoleic acid: 2.0.

[0085] Composite pyrolysis catalyst 2-2: Propylene glycol butyl ether: 6.0; Propylene glycol methyl ether: 10.0; Isopropanol: 10.0; 1,2-Propylene glycol: 10.0; Formamide: 4.0; Linoleic acid: 5.0.

[0086] Composite pyrolysis catalyst 2-3: Propylene glycol butyl ether: 4.0; Propylene glycol methyl ether: 8.0; Isopropanol: 6.0; 1,2-Propylene glycol: 7.0; Formamide: 2.0; Linoleic acid: 3.0.

[0087] Composite cracking catalyst 2-4: comprising propylene glycol butyl ether: 4.0 parts; propylene glycol methyl ether: 8.0 parts; ethylene glycol: 5 parts; ethylene glycol butyl ether: 12.0 parts; azone: 4.0 parts; formamide: 4.0 parts; xylene: 6 parts; isopropanol: 8.0 parts; cyclohexanone: 5.0 parts; cyclohexanol: 2.0 parts; linoleic acid: 2.0 parts; dichloromethane: 6.0 parts.

[0088] The composite oxidant is: sodium peroxide: 1.0; ferric iron powder: 8.0; triazine: 10.0.

[0089] (1) First, add the chemical reagents in the composite pyrolysis catalyst into the composite reactor in the order of their weight ratio;

[0090] (2) Based on the properties of isopropanol, which has a stronger solubility for lipophilic substances than ethanol, isopropanol is first added to the compounding reactor, followed by linoleic acid. After the linoleic acid is completely diluted by turning on the stirrer, other chemical reagents are added. Since linoleic acid is relatively viscous, it is dissolved in isopropanol before being mixed with other reagents.

[0091] (3) After the compounded pyrolysis catalyst is stored for 2 hours, it is ready for use.

[0092] (4) Composite oxidants are strong oxidants and are very active. They do not need to be mixed in advance and can be used according to the required weight ratio.

[0093] (5) After the coking coal is washed by the coal washing machine, impurities such as gangue and inorganic sulfur in the coal are removed. Weigh 5 tons and transport them to the hammer crusher for crushing. The particle size of the crushed coal should be controlled to be less than 15mm. Crush it to a particle size of less than 80 mesh or 60 mesh for later use.

[0094] (6) The crushed coking coal is conveyed to the mixer by a screw conveyor. When entering the mixer, the pre-mixed composite cracking catalyst is diluted once with 5 times its weight of water. Then, the diluted material is diluted a second time by a high-pressure metering pump at a weight ratio of 5 kg composite cracking catalyst diluted material to 1000 kg water. Then, it is sprayed into the coking coal. The raw coal and the diluted cracking catalyst are fully mixed evenly in the mixer at a weight ratio of 10:2. Then, it enters the screw catalytic cracking reactor and is heated to 35℃-60℃ at the same time. The stirrer is turned on and the pre-catalytic reaction is carried out for 0-60 minutes. Then, the temperature is raised to 60-80℃ and the reaction time is 90 minutes before entering the oxidation reaction process section.

[0095] (7) After the coking coal has completed the pyrolysis catalytic reaction, add sodium peroxide. Add 5 kg of sodium peroxide to 1000 kg of coking coal and add it to the reactor. Continue the reaction for 60 minutes. (If it is sulfur recovery, wash the coal after the oxidation reaction and use a plate and frame filter press to dehydrate the coal. The sulfur-containing water removed will enter the sulfur recovery system. Because this patent is for desulfurization by pyrolysis catalyst, sulfur recovery will not be described in detail in this patent.) Then add 8.0 kg of trivalent iron powder and 10 kg of triazine (10 kg: 100 kg water dilution) to the reactor at once. Continue the reaction for 30 minutes. The oxidation desulfurization process is completed and the process enters the washing process.

[0096] (8) After the catalytic cracking and oxidation reactions are completed, the coal is transported to the coal washing machine by a screw conveyor. The sulfides and small water-soluble sulfides produced by the catalytic cracking and oxidation reactions are washed out to achieve the purpose of thoroughly removing sulfur from the coal.

[0097] (9) The washed coal slurry is pumped to a plate and frame filter press for solid-liquid separation using a mud pump. The separated filtrate is pumped to a storage tank, where it is recycled after simple filtration and sedimentation. Before use, the residual composite pyrolysis catalyst content in the circulating water should be tested, and new composite pyrolysis catalyst should be added once based on the test results before recycling. No composite oxidant needs to be added in this process section because the residual composite oxidant content is small and negligible, and will not affect the next pyrolysis catalytic reaction.

[0098] (10) After solid-liquid separation, the clean coal is conveyed by belt conveyor to a rotary drum dryer. At a temperature of 105℃-150℃, the residual composite cracking catalyst and composite oxidant in the coal are evaporated. The evaporated steam is then drawn into a condenser for condensation and recovery. The recovered liquid is drawn into the circulating water storage tank in step (9) for testing and treatment before being recycled. The coal is required to be dried to a moisture content of less than 12-15%.

[0099] (11) After coal goes through the stages of catalysis, cracking, oxidation and desulfurization, high-quality clean coal with a sulfur content of less than 0.8-1.0 is obtained.

[0100] Example 3, Coal pretreatment method

[0101] Composite cracking catalyst: Ethylene glycol: 15.0; Ethylene glycol butyl ether: 10.0; Polyethylene glycol (600): 5.0; Xylene: 10.0; n-Butanol: 5.0; Octadecyl dimethyl ammonium chloride: 3.0.

[0102] The composite oxidant consists of sodium peroxide: 2.0; ferric iron powder: 3.0; and triazine: 10.0.

[0103] The sum of the weight percentages of the above complexes is 100%.

[0104] 2. Specific operation methods:

[0105] (1) First, add the chemical reagents in the composite pyrolysis catalyst into the composite pyrolysis catalyst compounding reactor according to the required weight percentage and the properties of the chemical reagents.

[0106] (2) First, add xylene to the reactor as required, then add octadecyl dimethyl ammonium chloride and turn on the stirrer. After confirming complete dilution, add polyethylene glycol 600 and turn on the stirrer again. After complete dilution, add other chemical reagents in turn, continue stirring for 20 minutes, and then let it stand for 30 minutes before use. Since octadecyl dimethyl ammonium chloride is a waxy substance and not easily soluble in common solvents, xylene is used to dissolve it before mixing with other reagents.

[0107] (3) Composite oxidants, due to their strong oxidizing properties, are not suitable for pre-mixing. They should be prepared and used immediately during production according to the required weight ratio.

[0108] (4) Take 10 tons of coal and crush it to less than 3mm for later use.

[0109] (5) The pulverized coal powder is transported to the mixer by a screw conveyor for mixing. When entering the mixer, the pre-mixed composite cracking catalyst is diluted once with the same weight of water. Then, the first dilution is diluted a second time by a high-pressure metering pump at a weight ratio of 5 kg composite cracking catalyst dilution to 1000 kg water. Finally, the high-pressure metering pump is used to spray the pulverized coal powder to make it uniform.

[0110] (6) After the coal powder is mixed evenly, it is conveyed to coal bunker (No. 1) by a screw conveyor and heated to 60°C at the same time. The agitator is turned on and the pre-catalytic reaction is carried out for 30 minutes. Then the temperature is raised to 80°C and the catalytic reaction is carried out for 180 minutes. Then it is conveyed to mixer (No. 2) by a screw conveyor. When entering mixer (No. 2), 2 kg of sodium peroxide and 3 kg of trivalent iron powder and 10 kg of triazine are added to 1000 kg of coking coal. After the reaction is continued for 60 minutes, it becomes low-sulfur coal with a sulfur content of less than 0.1. Since the desulfurizing agent can achieve an irreversible reaction when removing sulfides, the desulfurized coal can be used directly.

[0111] Example 4, Coal pretreatment method for combustion

[0112] Composite cracking catalyst: Cyclohexanol: 5.0; Cyclohexanone: 1.5; Azone: 5.0; Dichloromethane: 10.0; Methanol: 10.0; Octadecyldimethylammonium chloride: 10 parts.

[0113] The composite oxidant is: sodium peroxide: 3.0; trivalent iron powder: 8.0; mestriazine: 10.0; octadecanedimethylammonium chloride: 5 parts.

[0114] 2. Specific operation methods:

[0115] (1) First, the chemical reagents in the composite pyrolysis catalyst are compounded according to their properties and characteristics, and according to the required weight percentage.

[0116] (2) Based on the dilutive properties of methanol, it is first added to the composite cracking catalyst reactor according to the required weight percentage. Then, azone is added according to the required weight percentage, and the stirrer is turned on for dilution. After confirming complete dilution, other chemical reagents are added, and stirring is continued for 30 minutes. After standing for 60 minutes, it is ready for use. Since azone is insoluble in water, it is first dissolved in methanol, then mixed with other reagents, and then diluted.

[0117] (3) Composite oxidizing desulfurizer, because of its strong oxidizing properties, should be prepared and used on the actual production line according to the required weight percentage.

[0118] (4) Considering the low hardness of bituminous coal and the strong permeability of the azone chemical reagent used in the composite cracking catalyst, this example three adopts the stockpile method.

[0119] (5) Take 10 tons of bituminous coal and crush it to a particle size of less than 5 mm. When it enters the crusher, first dilute the pre-mixed composite cracking catalyst in step (3) with 10 times the weight of water. Then, use a high-pressure metering pump to dilute the first dilution a second time at a weight ratio of 5 kg composite cracking catalyst dilution to 1000 kg water. Use a high-pressure metering pump to spray the raw coal and the diluted cracking catalyst onto the coal powder at a weight ratio of 1:1. After the mixture is fully and evenly mixed in the mixer, it is then transported to the stockpile by a belt conveyor and covered with plastic sheeting. After 8 hours of reaction, the cracking catalytic reaction is completed.

[0120] (6) After the cracking catalytic reaction is completed, add 3 kg of sodium peroxide to 1000 kg of coking coal, then add 8 kg of trivalent iron powder, 10 kg of mestriazine, and 15 kg of octadecanedimethylammonium chloride. Use a loader to stir the coal evenly, then cover it with plastic sheeting. After the reaction is completed, it is not necessary to wash the desulfurized coal, because the composite oxidative desulfurizing agent can achieve an irreversible reaction when removing coal sulfides, so it can be used immediately after the reaction is completed.

[0121] Example 5, Coal pretreatment method

[0122] Composite cracking catalyst: Cyclohexanol: 5.0; Cyclohexanone: 1.5; Azone: 5.0; Dichloromethane: 10.0; Methanol: 10.0.

[0123] The composite oxidant is: sodium peroxide: 3.0; trivalent iron powder: 8.0; triazine: 10.0; octadecanedimethylammonium chloride: 15 parts.

[0124] The operating steps are the same as in Example 4, except that all octadecanedimethylammonium chloride is used as a composite oxidant for the desulfurization treatment of bituminous coal.

[0125] Table 1 summarizes the parameter comparisons of different pulverized coals before and after desulfurization treatment in Examples 2-5.

[0126] Table 1. Summary of parameters of different pulverized coal in Examples 2-5 before and after desulfurization treatment.

[0127]

[0128]

[0129] The method provided by this invention, used for pre-combustion treatment of coal, significantly reduces the sulfur content of coal, decreasing it by up to 76%. This invention utilizes catalytic cracking under normal pressure, without damaging other components of the coal. After cracking, organic sulfur molecules dissolve into smaller molecules, allowing the desulfurizing agent to penetrate the coal and thus remove organic sulfur. Simultaneously, it ensures that the physical and chemical properties of the treated coal remain unchanged.

[0130] In Example 5, the lack of a swelling agent affected the dispersion of sulfur components from coal into the solvent, resulting in poor desulfurization effect.

[0131] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for pre-treatment of coal before combustion, characterized in that, A composite pyrolysis catalyst is used, which comprises 2-6 parts of a penetrant, 10-40 parts of a swelling agent, and 2-30 parts of a solvent; The penetrant is selected from one or more of the following components: azone, linoleic acid, or octadecyltrimethylammonium chloride; The swelling agent is selected from one or more of the following components: octadecyltrimethylammonium chloride, formamide, polyethylene glycol 600, ethylene glycol butyl ether, isopropanol, propylene glycol methyl ether, and 1,2-propanediol. The solvent is selected from one or more of the following components: propylene glycol butyl ether, ethylene glycol, cyclohexanol, cyclohexanone, dichloromethane, xylene, methanol, and n-butanol. Includes the following steps: Step 1, Material Preparation Process: The coal is washed, sorted, and then crushed. Step 2, Pre-catalytic process section: The pulverized coal powder from step 1 is fed into a mixer. The diluted composite pyrolysis catalyst is sprayed onto the coal powder and mixed evenly. Then, it is transferred to a pre-catalytic reactor and heated to 35℃-60℃. The agitator is turned on, and the pre-catalytic reaction is carried out for 30-60 minutes. The dilution process of the composite pyrolysis catalyst is as follows: the pre-mixed composite pyrolysis catalyst is diluted once with 1-10 times its weight of water, and then the diluted material is diluted a second time with 200 times its weight of water using a high-pressure metering pump. Step 3, pyrolysis catalytic reaction and oxidative desulfurization process section: After the pre-catalytic reaction is completed, the coal slurry is transported to the pyrolysis catalytic reactor, stirred, and heated to 60-80℃. After a reaction time of 90-180 minutes, it enters the oxidation reaction process section. Sodium peroxide is added; 5 kg of sodium peroxide is added to 1000 kg of coking coal and added to the reactor. After reacting for another 60 minutes, trivalent iron powder and triazine, the desulfurizing agents, are added to the reactor all at once. After reacting for another 30 minutes, the oxidation desulfurization process section is completed. The composite pyrolysis catalyst used for desulfurization before coal combustion is catalytically pyrolyzed under normal pressure, allowing the desulfurizing agent to penetrate into the coal and achieve the removal of organic sulfur from the coal. Step 4, Coal washing process: After the cracking catalytic reaction and the oxidative desulfurization reaction are completed, the coal slurry is transported to the coal washing machine and washed with water. Step 5: Solid-liquid separation and filtrate recovery process: After the coal washing process is completed, the coal slurry is filtered using a plate and frame filter press to separate the solid and liquid components, thus obtaining the coal after solid-liquid separation. Step 6: Dry the coal after solid-liquid separation to obtain the finished product.

2. The coal pretreatment method according to claim 1, characterized in that: The composite pyrolysis catalyst comprises propylene glycol butyl ether: 2-6 parts; propylene glycol methyl ether: 5-10 parts; and isopropanol: 2-10 parts. Formamide: 2-6 parts; Linoleic acid: 2-5 parts; 1,2-propanediol: 5-10 parts.

3. The coal pretreatment method according to claim 1, characterized in that: The composite pyrolysis catalyst comprises 15-20 parts of ethylene glycol; Ethylene glycol butyl ether: 10-15 parts; Polyethylene glycol 600: 2-5 parts; Xylene: 10-15 parts; n-Butanol: 5-10 parts; Octadecyltrimethylammonium chloride: 2-5 parts.

4. The coal pretreatment method according to claim 1, characterized in that: The composite pyrolysis catalyst comprises 5-10 parts of cyclohexanol; Cyclohexanone: 1.5-10 parts; Azone: 1-5 parts; Dichloromethane: 10-15 parts; Methanol: 10-20 parts; Octadecyltrimethylammonium chloride: 5-15 parts.

5. The coal pretreatment method according to claim 1, characterized in that: The composite pyrolysis catalyst comprises propylene glycol butyl ether: 2-6 parts; propylene glycol methyl ether: 5-10 parts; Ethylene glycol: 5-20 parts; Ethylene glycol butyl ether: 10-15 parts; Azone: 1-5 parts; Formamide: 2-6 parts; Xylene: 5-15 parts; Isopropanol: 2.0-10.0 parts; Cyclohexanone: 1.5-10 parts; Cyclohexanol: 2-10 parts; Linoleic acid: 2-5 parts; Dichloromethane: 6-15 parts.

6. The coal pretreatment method according to claim 1, characterized in that: The composite pyrolysis catalyst contains azone, which is dissolved in methanol and then mixed with other components of the composite pyrolysis catalyst.

7. The coal pretreatment method according to claim 1, characterized in that: The composite pyrolysis catalyst contains octadecyltrimethylammonium chloride, which is dissolved in xylene and then mixed with other components of the composite pyrolysis catalyst.

8. The coal pretreatment method according to claim 1, characterized in that: The composite pyrolysis catalyst contains linoleic acid, which is dissolved in isopropanol and then mixed with other components of the composite pyrolysis catalyst.

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