A method for producing porous graphite electrodes from coal liquefaction residue

Abstract

The present invention provides a method for producing porous graphite electrodes from coal liquefaction residue. The method comprises: mixing the coal liquefaction residue with water, additives, crosslinking agents, dispersants, foaming agents, polymers and catalysts and forming the mixture into sheets to obtain coal liquefaction residue sheets; heating the coal liquefaction residue sheets to generate porous carbon sheets; sintering the porous carbon sheets and condensing them to obtain porous graphite electrodes. The technical solution provided by the present invention realizes the effective utilization of coal liquefaction residues, can produce high-value porous graphite electrodes, and can dry distill byproduct hydrocarbon oil in the process of preparing graphite electrodes. Compared with the traditional graphite electrode preparation method, the cost is lower, and the prepared porous graphite electrode has a large specific surface area, which can greatly increase the contact area between water and the electrode, and improve the efficiency of electrolysis or power generation.

Description

Technical Field

[0001] The invention relates to a method for producing porous graphite electrodes from coal liquefaction residues. Background Art

[0002] Coal direct liquefaction technology is an effective and clean method of coal utilization. During the coal direct liquefaction process, a residue accounting for about 1 / 3 of the original coal will be produced, which is the coal liquefaction residue. As a large amount of waste, if the coal liquefaction residue cannot be effectively treated, it will not only have a negative impact on the environment, but also be a waste of resources. The reuse of coal liquefaction residue is of great significance to controlling the cost of the coal liquefaction process.

[0003] Coal liquefaction residue is a complex solid mixture. After industrial analysis, it can be found that the residue contains almost no water, and its main characteristics are high carbon, high ash and high sulfur. Coal liquefaction residue mainly contains carbon, hydrogen, oxygen, sulfur, silicon, in addition to the metal elements contained in the coal liquefaction catalyst, of which carbon accounts for about 80%. Most of the ash in the residue is aluminosilicate, and the content is much higher than that of raw coal. This is due to the enrichment of minerals in the raw coal in the residue after liquefaction. Volatile substances are composed of pyrolysis products of organic matter in the raw coal that has not been completely liquefied.

[0004] In the direct coal liquefaction process, due to the different origins of the raw coal and the different production methods, the composition of the coal liquefaction residue obtained will vary to a certain extent. Its calorific value can usually reach 30MJ / kg, the softening point is generally around 180℃, and the density is 1.2-1.6g / cm 3 Coal liquefaction residue is very sensitive to temperature changes. When heated, the viscosity gradually decreases during the temperature increase process. Its viscosity is related to the carbon content. The higher the carbon content, the higher the viscosity. Through the pyrolysis characteristics test of coal liquefaction residue, it can be known that the organic matter in the residue is very violently pyrolyzed in the low temperature section, proving that it contains more oil substances.

[0005] The traditional utilization methods of coal liquefaction residue are mainly as follows: (1) Direct combustion: Coal liquefaction residue has high carbon content and high calorific value, and can be directly used as fuel for energy supply, and is often used in combination with raw coal, wood, etc. as boiler fuel. However, coal liquefaction residue also has the characteristics of high sulfur content, and a large amount of SO will be generated during the combustion process. 2, causing serious air pollution; (2) Hydrogenation liquefaction: Heavy oil and asphaltene can be further hydrogenated and liquefied due to their aromatic hydrocarbon structure, which not only improves the yield of raw coal liquefied oil, but also can obtain other high value-added oil products. However, the secondary hydrogenation reaction of coal liquefaction residue is difficult, the requirements for the equipment are strict, and the quality of the obtained oil products is unstable; (3) Gasification hydrogen production: The use of coal liquefaction residue to prepare hydrogen not only consumes the residue, but also provides hydrogen for the coal liquefaction production line. However, due to the high impurity content in the coal liquefaction residue, non-metallic elements such as sulfur are easily absorbed by O 2 Oxidized to SO 2 (4) Dry distillation: Coal liquefaction residue is the remaining material after the raw coal is liquefied. It is difficult to separate liquid products from the residue, but coking heavy oil and asphaltene can produce coke, distillable oil and gas.

[0006] In summary, there is still a need to study new methods to achieve the secondary utilization of coal liquefaction residue. Summary of the invention

[0007] The object of the present invention is to provide a method capable of realizing effective utilization of coal liquefaction residue, wherein the method can realize production of porous graphite electrodes by using coal liquefaction residue as raw material.

[0008] In order to achieve the above object, the present invention provides a method for producing a porous graphite electrode from coal liquefaction residue, wherein the method comprises:

[0009] Step 1): mixing the coal liquefaction residue with water, an additive, a cross-linking agent, a dispersant, a foaming agent, a polymer and a catalyst and forming the mixture into a sheet to obtain a coal liquefaction residue sheet;

[0010] Step 2): heating the coal liquefaction residue sheet to generate a porous carbon sheet;

[0011] Step 3): The porous carbon sheet is sintered and then condensed to obtain a porous graphite electrode.

[0012] The above method utilizes the characteristics of high organic component (heavy oil and asphaltene) content and large molecular weight in coal liquefaction residue, which is suitable for preparing carbon materials as a carbon source. The residue is mixed with water, additives, cross-linking agents, dispersants, foaming agents, polymers and catalysts to form a sheet and then heated to generate coke. The coke is sintered at high temperature and cooled to obtain a porous graphite electrode sheet, wherein hydrocarbon oil can be dry distilled during the heating process of generating coke. The porous graphite electrode sheet can be used as a graphite electrode in water electrolysis or fuel cells, which is beneficial to increase the contact area between water and the electrode and improve the efficiency of electrolysis or power generation.

[0013] Coal liquefaction residue contains more asphaltene and pre-asphaltene. Asphaltene and pre-asphaltene raw materials have low molecular weight. Through additives, cross-linking agents, etc., cross-linking reactions occur. Under the catalyst and optimized oxidation carbonization process, low molecular weight polycyclic aromatic hydrocarbons are further aromatized to form a graphite-like structure. Asphaltene and pre-asphaltene raw materials are used as carbon sources. The carbon yield is moderate, which can not only ensure the continuity of oxidation carbonization, but also form suitable sub-micro-nanoscale pores, so that the porous carbon structure has a certain strength to meet the mechanical properties and flexibility requirements of flexible electrodes, and has a reasonable pore volume and pore structure to meet the requirements of energy storage and release.

[0014] In the above method for producing a porous graphite electrode from coal liquefaction residue, preferably, based on the mass of the coal liquefaction residue being 100%, the total content of asphaltene and pre-asphaltene in the coal liquefaction residue is not less than 20%.

[0015] In the above-mentioned method for producing porous graphite electrodes from coal liquefaction residue, preferably, the additive includes polycyclic aromatic hydrocarbons, wherein polycyclic aromatic hydrocarbons refer to aromatic hydrocarbons with three or more rings; more preferably, the additive further includes paraffin; more preferably, polycyclic aromatic hydrocarbons can be added by adding polycyclic aromatic hydrocarbon-rich light mineral oil (such as catalytic cracking light cycle oil) and / or a polycyclic aromatic hydrocarbon mixture, wherein the mass content of polycyclic aromatic hydrocarbons in the polycyclic aromatic hydrocarbon-rich light mineral oil is not less than 50%.

[0016] In the above method for producing porous graphite electrodes from coal liquefaction residue, preferably, the crosslinking agent comprises one or a combination of two or more of polytriallyl isocyanurate, hydroxyethyl acrylate compounds, methacrylic acid compounds and blocked crosslinking agents.

[0017] In the above method for producing a porous graphite electrode from coal liquefaction residue, preferably, the dispersant comprises an oil-soluble polyether surfactant.

[0018] In the above method for producing porous graphite electrodes from coal liquefaction residue, preferably, the foaming agent includes one or a combination of two or more of hydrophilic polyurethane, carboxylic acids and salts thereof, alkyl sulfonic acids and salts thereof, phenols and pyridines.

[0019] In the above method for producing porous graphite electrodes from coal liquefaction residue, preferably, the polymerization agent includes one or a combination of two or more of polyvinyl n-butyl ether, vinyl vinyl sulfite, vinyl ethylene carbonate and alkyd resin surfactants.

[0020] In the above method for producing porous graphite electrodes from coal liquefaction residue, preferably, the catalyst comprises one or a combination of iron, nickel, titanium, silicon, and carbides and oxides thereof.

[0021] In the above method for producing a porous graphite electrode from coal liquefaction residue, preferably,

[0022] Coal liquefaction residue: water = 1:1-1:3

[0023] Coal liquefaction residue: additive = 3:1-3:2

[0024] Coal liquefaction residue: cross-linking agent = 3:1-8:1

[0025] Coal liquefaction residue: dispersant = 90:1-120:1

[0026] Coal liquefaction residue: foaming agent = 100:1-200:1

[0027] Coal liquefaction residue: polymerizer = 15:1-30:1

[0028] Coal liquefaction residue: catalyst = 4:1-6:1;

[0029] In a specific embodiment, the weight ratio of each component in the coal liquefaction residue piece is:

[0030] Coal liquefaction residue: water = 1:1

[0031] Coal liquefaction residue: additive = 3:1

[0032] Coal liquefaction residue: cross-linking agent = 5:1

[0033] Coal liquefaction residue: dispersant = 100:1

[0034] Coal liquefaction residue: foaming agent = 150:1

[0035] Coal liquefaction residue: polymerizer = 15:1

[0036] Coal liquefaction residue: catalyst = 5:1.

[0037] In the above method for producing a porous graphite electrode from coal liquefaction residue, preferably, the thickness of the coal liquefaction residue sheet is 1.0-1.5 mm (eg, 1.25 mm).

[0038] In the above method for producing porous graphite electrodes from coal liquefaction residue, the length and width of the coal liquefaction residue sheet can be determined according to the size of the porous graphite electrode to be prepared; in a specific embodiment, the length and width of the coal liquefaction residue sheet are 100 mm respectively.

[0039] In the above method for producing a porous graphite electrode from coal liquefaction residue, preferably, in step 1), the coal liquefaction residue mixed with water, additives, crosslinking agents, dispersants, foaming agents, polymerizing agents and catalysts is coal liquefaction residue that has been screened by particle size; the particle size of the coal liquefaction residue that has been screened by particle size is greater than 100 mesh;

[0040] More preferably, the particle size screening is performed by flotation.

[0041] In the above method for producing porous graphite electrodes from coal liquefaction residue, preferably, step 1) comprises:

[0042] The coal liquefaction residue is screened and then mixed with water; then an additive, a cross-linking agent and a dispersant are added in sequence to form a mixture; a foaming agent is added to the mixture to generate foam, and then a polymerizing agent and a catalyst are added, and the mixture is injected into a mold before forming a gel, and is formed into a sheet in the mold to obtain a coal liquefaction residue sheet;

[0043] More preferably, the coal liquefaction residue is first washed with water after screening and then mixed with water.

[0044] In the above method for producing porous graphite electrodes from coal liquefaction residue, preferably, step 2) comprises:

[0045] The coal liquefaction residue flakes are heated in an air-tight condition to distill out water vapor, gaseous reactants and hydrocarbon vapor;

[0046] Continue heating and raising the temperature (still maintaining the air-tight condition) to achieve thermal conversion reaction of high-boiling-point macromolecular hydrocarbons in the coal liquefaction residue flakes to crack into light hydrocarbons and distill them out in the form of hydrocarbon vapor, and part of the residues are coked to form coke, thereby obtaining a porous carbon flake;

[0047] More preferably, the step of heating the coal liquefaction residue pieces in an airtight condition to distill out water vapor, gaseous reactants and hydrocarbon vapor is achieved by: heating the coal liquefaction residue pieces in an airtight condition to 150-400° C. and keeping the temperature for 2-3 hours; further preferably, heating the coal liquefaction residue pieces in an airtight condition to 400° C. and keeping the temperature for 2-3 hours; further preferably, the heating rate of the heating is 20° C. / h;

[0048] More preferably, the step of continuing to heat and raise the temperature to achieve thermal conversion reaction of high-boiling-point macromolecular hydrocarbons in the coal liquefaction residue sheet to crack into light hydrocarbons and distill them out in the form of hydrocarbon vapor, and part of the residue is coked to form coke to obtain the porous carbon sheet is achieved by the following method:

[0049] Continue heating (still maintaining air isolation conditions) to 500-700°C and keep warm for 1.5-2.5 hours; more preferably, the heating rate is 25°C / h;

[0050] The air-isolated condition may be achieved by, but is not limited to, introducing an inert gas.

[0051] In the above method for producing porous graphite electrodes from coal liquefaction residue, preferably, the sintering is performed at 750-950° C. for 1-3 hours under a protective gas atmosphere.

[0052] In the above method for producing porous graphite electrodes from coal liquefaction residue, preferably, the density of the porous graphite electrode can be controlled to be 0.3-0.8 g / cm according to different ratios of additives. 3 .

[0053] In the above method for producing hydrocarbon oil and porous graphite electrode from coal liquefaction residue, preferably, in step 2), hydrocarbon vapor is distilled during the heating process of the coal liquefaction residue slices, and the hydrocarbon vapor is condensed and collected to obtain hydrocarbon oil.

[0054] In the above method for producing porous graphite electrodes from coal liquefaction residue, preferably, in step 2), water vapor is distilled during the heating process of the coal liquefaction residue sheets, and the distilled water vapor is condensed and collected in a sewage pool.

[0055] In the above method for producing a porous graphite electrode from coal liquefaction residue, preferably, the method further comprises:

[0056] The porous graphite electrode prepared in step 3) is cut, and optionally subjected to physical surface processing and / or chemical modification such as acid and alkali as required, and then cleaned and dried.

[0057] The present invention also provides a porous graphite electrode prepared by the method for producing a porous graphite electrode from the coal liquefaction residue.

[0058] In the above-mentioned porous graphite electrode, preferably, the specific surface area of ​​the porous graphite electrode is 220-500m 2 / g.

[0059] In the above-mentioned porous graphite electrode, preferably, the pore size distribution of the porous graphite electrode is 2-15 nm.

[0060] In the above-mentioned porous graphite electrode, preferably, the density of the porous graphite electrode is 0.3-0.8 g / cm 3 .

[0061] The technical solution provided by the present invention realizes the effective utilization of coal liquefaction residue, can produce high-value product porous graphite electrodes, and can dry distill by-product hydrocarbon oil in the process of preparing graphite electrodes. Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0062] 1. The technical solution provided by the present invention is lower in cost than the traditional graphite electrode preparation method. The prepared porous graphite electrode has a large specific surface area, which can greatly increase the contact area between water and the electrode and improve the electrolysis or power generation efficiency.

[0063] 2. The technical solution provided by the present invention mixes coal liquefaction residue with water, additives, cross-linking agents, dispersants, foaming agents, polymers and catalysts to form sheets and then heats them to generate coke. The coke is sintered at high temperature and cooled to obtain porous graphite electrode sheets. This process couples the two processes of thermal conversion of coal liquefaction residue and roasting of graphite electrode sheets to achieve the preparation of graphite electrode sheets. This process can produce hydrocarbon oil while producing graphite electrode sheets, and the produced hydrocarbon oil is of better quality than traditional water-washed coal liquefaction residue oil.

[0064] 3. The technical solution provided by the present invention avoids the generation of a large amount of waste water (the existing conventional coal liquefaction residue utilization method usually generates a large amount of waste water), significantly reduces the volume of powdered coal liquefaction residue, solves the problem that both water washing and coking cannot process powdered coal liquefaction residue, and realizes comprehensive utilization of resources.

[0065] 4. The technical solution provided by the present invention has small process investment, wide working conditions, strong applicability, easy operation, simple process, low cost, and has obvious economic, environmental and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 This is a flow chart of the method for producing porous graphite electrodes from coal liquefaction residue provided in Example 1 of the present invention.

[0067] Figure 2 This is the XRD spectrum of the porous graphite electrode provided in Example 1 of the present invention.

[0068] Figure 3 Graph showing the specific capacity (specific capacitance) of the porous graphite electrode provided in Example 1 and Comparative Example 1 of the present invention at different current densities. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0070] A specific embodiment of the present invention provides a method for producing a porous graphite electrode from coal liquefaction residue, wherein the method comprises:

[0071] Step 1): screening the coal liquefaction residue (residue produced in the direct coal liquefaction process) having a total mass content of asphaltene and pre-asphaltene of not less than 20% by particle size, washing the screened coal liquefaction residue with water, and then adding an additive, a cross-linking agent and a dispersant in sequence to form a mixture; adding a foaming agent to the mixture to generate foam, and then adding a polymerizing agent and a catalyst, injecting the mixture into a mold before forming a gel, and forming it into a sheet in the mold to obtain a coal liquefaction residue sheet;

[0072] Step 2): heating the coal liquefaction residue sheet to 150-400° C. in an airtight condition and keeping the temperature for 2-3 hours (this step is used to achieve distillation of water vapor, gaseous reactants and light hydrocarbons), continuing to heat and raise the temperature (still maintaining the airtight condition) to 500-700° C. and keeping the temperature for 1.5-2.5 hours (this step is used to achieve thermal conversion reaction and cracking of high-boiling point macromolecular hydrocarbons in the coal liquefaction residue sheet to generate light hydrocarbons and distill them out, and part of the residue is coked to generate coke), to obtain a porous carbon sheet; the hydrocarbon vapor distilled during the heating process is condensed to obtain hydrocarbon oil;

[0073] Step 3): The porous carbon sheet is sintered at 750-950° C. for 2 hours in a protective gas atmosphere to obtain a porous graphite electrode.

[0074] Wherein, taking the mass of the coal liquefaction residue as 100%, the total content of asphaltene and pre-asphaltene in the coal liquefaction residue is not less than 5.

[0075] Wherein, the additive includes polycyclic aromatic hydrocarbons, wherein polycyclic aromatic hydrocarbons refer to aromatic hydrocarbons with three or more rings; further, the additive further includes paraffin; further, the polycyclic aromatic hydrocarbons are added by adding polycyclic aromatic hydrocarbon-rich light mineral oil (such as catalytic cracking light cycle oil) and / or a polycyclic aromatic hydrocarbon mixture, wherein,

[0076] The mass content of polycyclic aromatic hydrocarbons in the polycyclic aromatic hydrocarbons-rich light mineral oil is not less than 50%.

[0077] 0 Wherein, the crosslinking agent includes polytriallyl isocyanurate, hydroxyethyl acrylate compounds, methyl

[0078] One or a combination of two or more of an acrylic compound and a blocked cross-linking agent.

[0079] Wherein, the dispersant includes an oil-soluble polyether surfactant.

[0080] The foaming agent comprises one or a combination of two or more of hydrophilic polyurethane, carboxylic acids and their salts, alkyl sulfonic acids and their salts, phenols and pyridines.

[0081] 5 Wherein, the polymerization agent includes polyvinyl n-butyl ether, vinyl sulfite, vinyl carbonate

[0082] One or a combination of two or more of ester and alkyd resin surfactants.

[0083] The catalyst comprises one or a combination of iron, nickel, titanium, silicon, their carbides and their oxides.

[0084] Among them, the weight ratio of each component in the coal liquefaction residue piece is:

[0085] 0 Coal liquefaction residue: water = 1:1-1:3

[0086] Coal liquefaction residue: additive = 3:1-3:2

[0087] Coal liquefaction residue: cross-linking agent = 3:1-8:1

[0088] Coal liquefaction residue: dispersant = 90:1-120:1

[0089] Coal liquefaction residue: foaming agent = 100:1-200:1

[0090] 5 Coal liquefaction residue: polymerizer = 15:1-30:1

[0091] Coal liquefaction residue: catalyst = 4:1-6:1.

[0092] The thickness of the coal liquefaction residue sheet is 1.0-1.5 mm.

[0093] The length and width of the coal liquefaction residue sheet can be determined according to the size of the porous graphite electrode to be prepared; for example, the length and width are 100 mm respectively.

[0094] Among them, particle size screening is carried out by flotation.

[0095] In the step 2), during the heating process of the coal liquefaction residue pieces, water vapor is distilled out, and the distilled water vapor is condensed and collected in a sewage pool.

[0096] The method further comprises: cutting the porous graphite electrode prepared in step 3), optionally performing surface processing by physical means and / or chemical modification such as acid and alkali as required, and then cleaning and drying.

[0097] Among them, according to the different ratios of additives, the density of porous graphite sheets can be controlled to 0.3-0.8g / cm 3 .

[0098] The specific surface area of ​​the porous graphite electrode prepared in the above specific embodiment is 220-500m 2 / g, pore size distribution is 2-15nm.

[0099] Example 1

[0100] This embodiment provides a method for producing porous graphite electrodes from coal liquefaction residues, and the process is as follows: Figure 1 shown.

[0101] The method includes:

[0102] The coal liquefaction residue (the total mass content of asphaltene and pre-asphaltene is greater than 20%) is screened by flotation to obtain the coal liquefaction residue with a particle size meeting the requirements;

[0103] The screened coal liquefaction residue is washed with water and then mixed with water, additives, cross-linking agents, dispersants, foaming agents, polymerizing agents and catalysts; specifically, the screened coal liquefaction residue is washed with water and then mixed with water, and then additives, cross-linking agents and dispersants are added in sequence to form a mixture; a foaming agent is added to the mixture to generate foam, and then a polymerizing agent and a catalyst are added; wherein the weight ratio of each component in the coal liquefaction residue sheet is: coal liquefaction residue: water = 1:1, coal liquefaction residue: additives = 3:1, coal liquefaction residue: cross-linking agent = 5:1, coal liquefaction residue: dispersant = 100:1, coal liquefaction residue: foaming agent = 150:1, coal liquefaction residue: polymerizing agent = 15:1, coal liquefaction residue: catalyst = 5:1; wherein , the additive is polycyclic aromatic hydrocarbons (in this embodiment, polycyclic aromatic hydrocarbons are added by adding catalytic cracking light cycle oil), the cross-linking agent is an ester-type closed cross-linking agent (in this embodiment, TMPTMA, brand T003M, a cross-linking agent for a free radical polymerization system is used), the dispersant is an oil-soluble polyether surfactant (in this embodiment, SH-200 is used), the foaming agent is a hydrophilic polyurethane surfactant (in this embodiment, a hydrophilic polyurethane surfactant modified by using C8-C12 alcohol and polyester, brand Q1-01ZY, a rare metal flotation foaming agent); the polymerizing agent is an alkyd resin surfactant (in this embodiment, GR-311, Kenrich KR-238S, is used), and the catalyst is a petroleum coke recarburizer;

[0104] The product obtained after mixing is injected into a mold before forming a gel, and is formed into a sheet in the mold to obtain a coal liquefaction residue sheet; wherein the thickness of the coal liquefaction residue sheet is 1.25 mm, and the length and width are 100 mm respectively;

[0105] The coal liquefaction residue sheet is placed in a fixed bed reactor (a closed rotary kiln is used in this embodiment) for heating treatment to obtain hydrocarbon oil and porous graphite electrodes; specifically: the coal liquefaction residue sheet is heated to about 100°C under air-tight conditions (achieved by introducing an inert gas into the fixed bed reactor) at a heating rate of 20°C / h to distill out water vapor, gaseous reactants and light hydrocarbons (in the form of hydrocarbon vapor), and the air-tight conditions are maintained to continue to be heated to 400°C and kept at a constant temperature for 2h to distill out the residual fuel fraction (in the form of hydrocarbon vapor); the air-tight conditions are maintained to continue to be heated to 600°C at a heating rate of 25°C / h and kept at a constant temperature for 2h to thermally convert the high-boiling point macromolecular hydrocarbons in the coal liquefaction residue sheet to crack into light hydrocarbons and distill them out (in the form of hydrocarbon vapor), and part of the residue is coked to form coke to obtain a porous carbon sheet; the porous carbon sheet is further heated to 800°C at a heating rate of 30°C / h and sintered at this temperature for 2 hours to obtain a porous graphite electrode;

[0106] The oil and gas obtained after the hydrocarbon vapor generated in the fixed bed reactor is condensed are transported to the oil and gas fractionation equipment for oil and gas fractionation, and hydrocarbon oil is obtained by condensation and collection. The gas component obtained by the oil and gas fractionation in the oil and gas fractionation equipment is sent to the liquefied gas storage tank for storage, and the obtained oil component is sent to the hydrocarbon oil storage tank for storage; the condensed water obtained after the water vapor generated in the fixed bed reactor is condensed is transported to the sewage pool for sewage treatment, and the clean water obtained by sewage treatment in the sewage pool is used for water washing and mixing with coal liquefaction residue;

[0107] The wastewater generated by washing the coal liquefaction residue is separated into oil and water, and the oil phase obtained by the oil-water separation is also transported to the oil and gas fractionation equipment for oil and gas fractionation, and the water phase obtained by the oil-water separation is also transported to the sewage pool for sewage treatment.

[0108] Among them, the raw materials stored in hydrocarbon oil storage tanks and liquefied gas storage tanks can be used as auxiliary fuel for heating the fixed bed reactor; the main fuel for heating the fixed bed reactor can be coal liquefaction residue or a mixture of coal liquefaction residue and coal; the exhaust gas generated by the combustion of fuel during the heating of the fixed bed reactor is treated with tail gas (the main component is CO 2 ) into the atmosphere.

[0109] The density of the porous graphite electrode prepared in this example is 0.8 g / cm 3 , with a specific surface area of ​​300m 2 / g, and the average pore size is 10nm.

[0110] The porous graphite electrode prepared in this example was subjected to XRD detection, and the results were as follows: Figure 2 shown.

[0111] Comparative Example 1

[0112] This comparative example provides a method for producing a porous graphite electrode from coal liquefaction residue. The difference between this comparative example and Example 1 is that no cross-linking agent is added.

[0113] The method includes:

[0114] The coal liquefaction residue (the total mass content of asphaltene and pre-asphaltene is greater than 20%) is screened by flotation to obtain the coal liquefaction residue with a particle size meeting the requirements;

[0115] The screened coal liquefaction residue is washed with water and then mixed with water, additives, dispersants, foaming agents, polymerizing agents and catalysts; specifically, the screened coal liquefaction residue is washed with water and then mixed with water, and then additives, crosslinking agents and dispersants are added in sequence to form a suspension mixture; a foaming agent is added to the suspension mixture to generate foam, and then a polymerizing agent and a catalyst are added; wherein the weight ratio of each component in the coal liquefaction residue piece is: coal liquefaction residue: water = 1:1, coal liquefaction residue: additives = 3:1, coal liquefaction residue: dispersant = 100:1, coal liquefaction residue: foaming agent = 150:1, coal liquefaction residue: polymerizing agent = 15: 1. Coal liquefaction residue: catalyst = 5:1; wherein the additive is polycyclic aromatic hydrocarbons (in this embodiment, polycyclic aromatic hydrocarbons are added by adding catalytic cracking light cycle oil), the dispersant is an oil-soluble polyether surfactant (SH-200 is used in this embodiment), the foaming agent is a hydrophilic polyurethane surfactant (a hydrophilic polyurethane surfactant modified by C8-C12 alcohol and polyester is used in this embodiment, brand Q1-01ZY, a rare metal flotation foaming agent); the polymerizing agent is an alkyd resin surfactant (GR-311 and Kenrich KR-238S are used in this embodiment), and the catalyst is a petroleum coke recarburizer;

[0116] The product obtained after mixing is injected into a mold before forming a gel, and is formed into a sheet in the mold to obtain a coal liquefaction residue sheet; wherein the thickness of the coal liquefaction residue sheet is 1.25 mm, and the length and width are 100 mm respectively;

[0117] The coal liquefaction residue sheet is placed in a fixed bed reactor (a closed rotary kiln is used in this embodiment) for heating treatment to obtain hydrocarbon oil and porous graphite electrodes; specifically: the coal liquefaction residue sheet is heated to about 100°C under air-tight conditions (achieved by introducing an inert gas into the fixed bed reactor) at a heating rate of 20°C / h to distill out water vapor, gaseous reactants and light hydrocarbons (in the form of hydrocarbon vapor), and the air-tight conditions are maintained to continue to be heated to 400°C and kept at a constant temperature for 2h to distill out the residual fuel fraction (in the form of hydrocarbon vapor); the air-tight conditions are maintained to continue to be heated to 600°C at a heating rate of 25°C / h and kept at a constant temperature for 2h to thermally convert the high-boiling point macromolecular hydrocarbons in the coal liquefaction residue sheet to crack into light hydrocarbons and distill them out (in the form of hydrocarbon vapor), and part of the residue is coked to form coke to obtain a porous carbon sheet; the porous carbon sheet is further heated to 800°C at a heating rate of 30°C / h and sintered at this temperature for 2 hours to obtain a porous graphite electrode;

[0118] The oil and gas obtained after the hydrocarbon vapor generated in the fixed bed reactor is condensed are transported to the oil and gas fractionation equipment for oil and gas fractionation, and hydrocarbon oil is obtained by condensation and collection. The gas component obtained by the oil and gas fractionation in the oil and gas fractionation equipment is sent to the liquefied gas storage tank for storage, and the obtained oil component is sent to the hydrocarbon oil storage tank for storage; the condensed water obtained after the water vapor generated in the fixed bed reactor is condensed is transported to the sewage pool for sewage treatment, and the clean water obtained by sewage treatment in the sewage pool is used for water washing and mixing with coal liquefaction residue;

[0119] The wastewater generated by washing the coal liquefaction residue is separated into oil and water, and the oil phase obtained by the oil-water separation is also transported to the oil and gas fractionation equipment for oil and gas fractionation, and the water phase obtained by the oil-water separation is also transported to the sewage pool for sewage treatment.

[0120] Among them, the raw materials stored in hydrocarbon oil storage tanks and liquefied gas storage tanks can be used as auxiliary fuel for heating fixed bed reactors; the main fuel for heating fixed bed reactors can use coal liquefaction residue scraps or a mixture of coal liquefaction residue scraps and coal; the exhaust gas generated by the combustion of fuel during the heating of the fixed bed reactor is discharged into the atmosphere after tail gas treatment (the main component is CO2).

[0121] The density of the porous graphite electrode prepared in this example is 0.4 g / cm 3 , with a specific surface area of ​​200m 2 / g, and the average pore size is 7nm.

[0122] The porous graphite electrodes prepared in Example 1 and Comparative Example 1 were tested for specific capacitance at different current densities. The results are as follows: Figure 3 shown.

Claims

1. A method for producing porous graphite electrodes from coal liquefaction residues, in, The method includes: Step 1): mixing the coal liquefaction residue with water, an additive, a cross-linking agent, a dispersant, a foaming agent, a polymerization agent and a catalyst and forming the mixture into a sheet to obtain a coal liquefaction residue sheet; Step 2): heating the coal liquefaction residue sheet to generate a porous carbon sheet; Step 3): the porous carbon sheet is sintered and then condensed to obtain a porous graphite electrode; Wherein, based on the mass of the coal liquefaction residue as 100%, the total content of asphaltene and pre-asphaltene in the coal liquefaction residue is not less than 20%; Wherein, the additives include polycyclic aromatic hydrocarbons, which refer to aromatic hydrocarbons with three or more rings; Wherein, the crosslinking agent includes one or a combination of two or more of polytriallyl isocyanurate, hydroxyethyl acrylate compounds, methacrylic acid compounds and blocked crosslinking agents; Wherein, the dispersant comprises an oil-soluble polyether surfactant; Wherein, the foaming agent comprises one or a combination of two or more of hydrophilic polyurethane, carboxylic acids and their salts, alkyl sulfonic acids and their salts, phenols and pyridines; Wherein, the polymerization agent includes one or a combination of two or more of polyvinyl n-butyl ether, vinyl sulfite, vinyl ethylene carbonate and alkyd resin surfactant; The catalyst comprises one or a combination of iron, nickel, titanium, silicon, their carbides and their oxides.

2. The method according to claim 1, in, The additives further include paraffin wax.

3. The method according to claim 1, in, The weight ratio of each component in the coal liquefaction residue flakes is: Coal liquefaction residue: water = 1:1-1:3 Coal liquefaction residue: additive = 3:1-3:2 Coal liquefaction residue: cross-linking agent = 3:1-8:1 Coal liquefaction residue: dispersant = 90:1-120:1 Coal liquefaction residue: foaming agent = 100:1-200:1 Coal liquefaction residue: polymerizer = 15:1-30:1 Coal liquefaction residue: catalyst = 4:1-6:

1.

4. The method according to claim 1, in, The thickness of the coal liquefaction residue sheet is 1.0-1.5 mm.

5. The method according to claim 1, in, In step 1), the coal liquefaction residue mixed with water, additives, crosslinking agent, dispersant, foaming agent, polymerization agent and catalyst is coal liquefaction residue that has been screened by particle size; the particle size of the coal liquefaction residue that has been screened by particle size is greater than 100 meshes.

6. The method according to claim 5, in, Particle size screening is carried out by flotation.

7. The method according to any one of claims 1 to 6, in, Step 1) includes: The coal liquefaction residue is screened and then mixed with water; then additives, crosslinking agents and dispersants are added in sequence to form a mixture; a foaming agent is added to the mixture to generate foam, and then a polymerizing agent and a catalyst are added, and the mixture is injected into a mold before forming a gel, and formed into a sheet in the mold to obtain a coal liquefaction residue sheet.

8. The method according to claim 1, in, Step 2) includes: The coal liquefaction residue flakes are heated in an air-tight condition to distill out water vapor, gaseous reactants and hydrocarbon vapor; The temperature is continued to be raised to achieve thermal conversion reaction of high-boiling-point macromolecular hydrocarbons in the coal liquefaction residue sheet to crack into light hydrocarbons which are distilled out in the form of hydrocarbon vapor, and part of the residue is coked to form coke to obtain a porous carbon sheet.

9. The method according to claim 8, in, The step of heating the coal liquefaction residue pieces in an airtight condition to distill out water vapor, gaseous reactants and hydrocarbon vapor is achieved by the following method: heating the coal liquefaction residue pieces in an airtight condition to 150-400° C. and keeping the temperature for 2-3 hours.

10. The method according to claim 9, in, The heating rate of the heating is 20°C / h.

11. The method according to claim 8, in, The step of continuing to heat and raise the temperature to achieve thermal conversion reaction of high-boiling-point macromolecular hydrocarbons in the coal liquefaction residue pieces to crack into light hydrocarbons and distill them out in the form of hydrocarbon vapor, and part of the residue is coked to form coke to obtain the porous carbon sheet is achieved by the following method: continue to heat and raise the temperature to 500-700°C.

12. The method according to claim 11, in, The heating rate of the heating is 25°C / h.

13. The method according to claim 1, in, The sintering is carried out at 750-950° C. for 1-3 hours in a protective gas atmosphere.

14. The method according to claim 1, in, Step 2), during the heating process of the coal liquefaction residue flakes, hydrocarbon vapor is distilled out, and the hydrocarbon vapor is condensed and collected to obtain hydrocarbon oil.

15. A porous graphite electrode prepared by the method for producing a porous graphite electrode from coal liquefaction residue according to any one of claims 1 to 14.

16. The porous graphite electrode according to claim 15, in, The specific surface area of ​​the porous graphite electrode is 750-950m 2 / g.

17. The porous graphite electrode according to claim 15, in, The pore size of the porous graphite electrode is distributed in the range of 2-15 nm.

18. The porous graphite electrode according to claim 15, in, The density of porous graphite electrode is 0.3-0.8g / cm 3 .

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