A composition for preparing a carbon-based heat storage material with high friction coefficient, a carbon-based heat storage material, a preparation method and applications

Abstract

The present disclosure relates to a composition for preparing a carbon-based thermal storage material with high friction coefficient, a carbon-based thermal storage material and a preparation method and application. The composition comprises 16-76 wt% of coke, 0-60 wt% of a thermal conductive agent and 20-28 wt% of a binder, based on the total weight of the composition. The carbon-based thermal storage material has a friction coefficient of 0.52-0.88, preferably 0.52-0.78; a density of 1.47-1.61 g / cm ‑3 , preferably 1.58-1.61 g / cm ‑3 ; a thermal conductivity of 7.2-35.6 W / mK, preferably 19.0-35.6 W / mK; and a compressive strength of 14.0-18.5 MPa, preferably 15.1-16.9 MPa. The carbon-based thermal storage material prepared by using the composition of the present disclosure has a high friction coefficient, and has high thermal conductivity and compressive strength. Moreover, the preparation method is simple and the production cost is low.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of heat storage materials, in particular, to a composition for preparing a carbon-based heat storage material with high friction coefficient, a carbon-based heat storage material, a preparation method and applications. BACKGROUND

[0002] Sensible heat storage technology is one of the most mature heat storage methods, which has simple operation mode, low cost and long service life. Compared with traditional heat storage materials such as magnesium and aluminum oxide, carbon-based heat storage materials have higher thermal conductivity, heat storage temperature and heat storage density, and have significant advantages.

[0003] Patent CN115181554A discloses a coal-based heat storage carbon material and its preparation method and application, which mainly uses graphite with different ID / IG as the aggregate component of the carbon-based heat storage material. The aggregate component is divided into two categories by ID / IG value, one category is 0-0.6, and the other category is >1. Through this compounding method, the coal-based heat storage material can have high compressive strength and high thermal conductivity. Patent CN107673759A discloses a preparation method of a new type of solar thermal power generation graphite heat storage material, which uses special graphite powder as raw material. The prepared graphite material has excellent physical and chemical indicators and can be widely used in the field of solar thermal power generation graphite heat storage materials. CN115140724A discloses a heat storage carbon material, its preparation method and application, and a composition for preparing a heat storage carbon material. It uses high graphitization degree graphite with graphitization degree ≥92% as the main raw material to form specific overall orientation and z-plane orientation. The overall orientation D(x) / D(z) of the heat storage carbon material is 500-900, and the z-plane orientation D(z) / E(z) is 0.2-8. The compressive strength of the heat storage carbon material is 20-60 MPa, and the thermal conductivity is 200-500 W / mK. The heat storage carbon material has high graphitization degree and specific overall orientation and z-plane orientation, so the heat storage carbon material has high molding density, thermal conductivity and compressive strength.

[0004] As can be seen, the existing carbon-based heat storage material technology mainly selects high graphitization degree and high orientation degree natural graphite or artificial graphite as raw material, and the prepared heat storage material can obtain high thermal conductivity. However, the carbon atoms in graphite form a hexagonal network of layers with sp2 hybridization, and the van der Waals force between the layers is weak, making the friction coefficient of graphite as low as 0.03 at room temperature. In particular, in order to improve the thermal conductivity, large flake graphite is used, and the prepared material has high thermal conductivity but low friction coefficient. Therefore, the carbon-based heat storage material using graphite as raw material has too low friction coefficient, which makes the heat storage material prone to slip during compounding. Not only is it not conducive to the transportation and hoisting of the product, but also an additional fixing system needs to be added during the assembly of the heat storage system, which increases the process steps, improves the complexity of the system, and increases the cost of the system. SUMMARY

[0005] To solve the above technical problems, the present disclosure provides a composition for preparing a carbon-based thermal storage material with high friction coefficient, a carbon-based thermal storage material with high friction coefficient, and a preparation method and application. The carbon-based thermal storage material has a high friction coefficient, and has high thermal conductivity and compressive strength.

[0006] To achieve the above-mentioned purpose, the present disclosure provides a composition for preparing a carbon-based thermal storage material with high friction coefficient. The composition includes, based on the total weight of the composition: 16-76% by weight of coke, 0-60% by weight of a thermal conductive agent, and 20-28% by weight of a binder.

[0007] Among them, based on the total weight of the coke, the volatile content of the coke is 1.0-1.2% by weight, the ash content is 7.8-10% by weight, and the fixed carbon content is 88.8-91.2% by weight.

[0008] Optionally, based on the total weight of the composition, the composition includes: 16-46% by weight of coke, 30-60% by weight of a thermal conductive agent, and 22-26% by weight of a binder.

[0009] Optionally, in the composition, the weight ratio of the coke to the thermal conductive agent is (0.26-1.54):1.

[0010] Optionally, the average particle size of the coke is 0.075-3mm;

[0011] The thermal conductive agent is a graphite material, wherein the average particle size of the graphite material is 50-200 mesh, the carbon content is 95-98%, and the graphitization degree is 98-99%; the graphite material is selected from one or more of natural flake graphite, graphitized petroleum coke, graphitized needle coke, and graphite electrode broken material; preferably natural flake graphite and / or graphitized petroleum coke;

[0012] The binder is pitch and / or resin, preferably pitch;

[0013] Optionally, the pitch is selected from mesophase pitch and / or non-mesophase pitch; wherein the softening point of the mesophase pitch is 175-200℃, and the carbon residue rate is 80-95% by weight; the softening point of the non-mesophase pitch is 75-95℃, and the carbon residue rate is 55-60% by weight; optionally, the mesophase pitch is selected from one or more of coal mesophase pitch, petroleum-based mesophase pitch, and pure aromatic mesophase pitch, and the non-mesophase pitch is selected from coal pitch and / or petroleum pitch; preferably, the weight ratio of the mesophase pitch to the non-mesophase pitch is 0.1:(0-1).

[0014] The second aspect of the present disclosure provides a method for preparing a carbon-based heat storage material with high friction coefficient, comprising the following steps:

[0015] S1, mixing the composition of the first aspect to obtain a raw material mixture;

[0016] S2, performing a molding treatment on the raw material mixture to obtain a raw material green body;

[0017] S3, performing an embedding treatment and a sintering treatment on the raw material green body.

[0018] Optionally, in step S1, the mixing treatment comprises: mixing the coke and the heat-conducting agent at 120-130℃ and 50-60r / min for 30-60min to obtain a first mixture; mixing the first mixture and the binder at 160-210℃ and 50-60r / min for 15-30min to obtain the raw material mixture.

[0019] Optionally, in step S2, the molding treatment is performed under the following conditions: a molding pressure of 100-130MPa; a molding temperature of 90-95℃; and a pressure holding time of 1-3min.

[0020] Optionally, in step S3, the sintering treatment is performed under the following conditions: a sintering temperature of 800-850℃; a sintering time of 1-2h; and a sintering atmosphere of air; preferably, the heating rate for heating to the sintering temperature is 0.3-0.5℃ / min.

[0021] The third aspect of the present disclosure provides the carbon-based heat storage material with high friction coefficient prepared by the method of the second aspect, wherein the carbon-based heat storage material has a friction coefficient of 0.52-0.88, preferably 0.52-0.78; a density of 1.47-1.61g / cm -3 , preferably 1.58-1.61g / cm -3 ; a thermal conductivity of 7.2-35.6W / mK, preferably 19.0-35.6W / mK; and a compressive strength of 14.0-18.5MPa, preferably 15.1-16.9MPa.

[0022] The fourth aspect of the present disclosure provides the use of the composition of the first aspect or the carbon-based heat storage material with high friction coefficient of the third aspect in a heat storage system in the field of heat storage heating and / or heat storage steam generation.

[0023] Through the above technical solutions, the present disclosure provides a composition for preparing a carbon-based heat storage material with high friction coefficient, a carbon-based heat storage material, a preparation method and application. The carbon-based heat storage material prepared by using the composition of the present disclosure has a high friction coefficient, and has a high thermal conductivity and a high compressive strength. Moreover, the preparation method is simple and the production cost is low.

[0024] Other features and advantages of the present disclosure will be described in detail in the following detailed description section. DETAILED DESCRIPTION

[0025] The following detailed description of the present disclosure is described in detail. It should be understood that the specific implementation described herein is only for illustration and explanation of the present disclosure, and is not intended to limit the present disclosure.

[0026] The first aspect of the present disclosure provides a composition for preparing a high-friction coefficient carbon-based thermal storage material, wherein the composition comprises, based on the total weight of the composition: 16-76 wt% of coke, 0-60 wt% of a thermal conductor and 20-28 wt% of a binder;

[0027] wherein, based on the total weight of the coke, the coke has a volatile content of 1.0-1.2 wt%, an ash content of 7.8-10 wt% and a fixed carbon content of 88.8-91.2 wt%.

[0028] The present disclosure provides a composition for preparing a high-friction coefficient carbon-based thermal storage material, which can be used to prepare a carbon-based thermal storage material. The composition of the present disclosure uses coke as an aggregate, and combines a thermal conductor and a binder to prepare a carbon-based thermal storage material with a high friction coefficient, effectively overcoming the problem of interlayer slip of the carbon-based thermal storage material. In particular, the carbon-based thermal storage material prepared using the composition formula described above not only improves the friction coefficient of the carbon-based thermal storage material, but also maintains the thermal conductivity and compressive strength of the carbon-based thermal storage material.

[0029] In a preferred embodiment of the present disclosure, the composition comprises, based on the total weight of the composition: 16-46 wt% of coke, 30-60 wt% of a thermal conductor and 22-26 wt% of a binder. The composition formula provided in this embodiment can be used to prepare a carbon-based thermal storage material with better performance, further improving the friction coefficient of the carbon-based thermal storage material.

[0030] In order to further improve the performance of the high-friction coefficient carbon-based thermal storage material, in a preferred embodiment of the present disclosure, the weight ratio of the coke to the thermal conductor in the composition is (0.26-1.54): 1.

[0031] The composition in the above embodiments uses coke as an aggregate and combines a thermal conductor with a suitable ratio to further improve the friction coefficient and thermal conductivity of the carbon-based thermal storage material.

[0032] In an embodiment of the present disclosure, the average particle size of the coke is 0.075-3 mm. The coke used in the present disclosure has a volatile matter content of 1.0-1.2 wt%, an ash content of 7.8-10 wt%, and a fixed carbon content of 88.8-91.2 wt%. The coke is composed of graphite-like microcrystals with regular structure and amorphous carbon with irregular structure, and has the advantages of low volatile matter content, low ash content, and high fixed carbon content, which is beneficial to improve the friction coefficient, thermal conductivity, and compressive strength of the carbon-based thermal storage material.

[0033] More specifically, the coke used in the present disclosure can have the following specifications, for example, the coke can have a particle size of 200 mesh, or an average particle size of 1-3 mm, both of which are purchased from Shanxi Coking Co., Ltd.

[0034] In an embodiment of the present disclosure, the heat-conducting agent is a graphite material, wherein the average particle size of the graphite material is 50-100 mesh, preferably 50 mesh; the carbon content is 95-98%, preferably 98%; the graphitization degree is 98-99%, preferably 99%; the graphite material is selected from one or more of natural flake graphite, graphitized petroleum coke, graphitized needle coke, and graphite electrode broken material; preferably, the graphite material is natural flake graphite and / or graphitized petroleum coke. The use of the heat-conducting agent of the present embodiment can greatly improve the thermal conductivity of the carbon-based thermal storage material.

[0035] In an embodiment of the present disclosure, the binder is pitch and / or resin, preferably pitch; the pitch is selected from mesophase pitch and / or non-mesophase pitch; wherein the softening point of the mesophase pitch is 175-200°C, and the carbon residue rate is 80-95 wt%; the softening point of the non-mesophase pitch is 75-95°C, and the carbon residue rate is 55-60 wt%; optionally, the mesophase pitch can be selected from one or more of coal mesophase pitch, petroleum mesophase pitch, and pure aromatic mesophase pitch, and the non-mesophase pitch can be selected from coal pitch and / or petroleum pitch.

[0036] In the present disclosure, the binder can be only mesophase pitch, or a mixture of mesophase pitch and non-mesophase pitch, preferably, the weight ratio of mesophase pitch to non-mesophase pitch is 0.1: (0-1). Since the pitch has good compatibility with the coke and the heat-conducting agent, the use of pitch as the binder makes the carbon-based thermal storage material have good dispersion uniformity and quality stability. The softening point of the pitch can be measured by GBT 4507-2014 Pitch Softening Point Test Method Ball Method; the carbon residue rate of the pitch after carbonization can be measured by ASTM D2416- (2009) method; the mesophase content of the mesophase pitch is measured by GBT 38396-2019 Coking Pitch Products-Determination of Mesophase Content-Optical Reflection Microscopic Analysis Method.

[0037] The raw materials of the composition used in the present disclosure can be purchased through ordinary commercial channels or prepared by known methods.

[0038] The second aspect of the present disclosure provides a method for preparing a carbon-based thermal storage material with high friction coefficient, which comprises the following steps:

[0039] S1, mixing the composition of the first aspect to obtain a raw material mixture;

[0040] S2, performing a compaction treatment on the raw material mixture to obtain a raw material green body;

[0041] S3, performing an embedding treatment and a sintering treatment on the raw material green body.

[0042] The present disclosure also provides a method for preparing a carbon-based thermal storage material with high friction coefficient, which can effectively mix the pitch binder with the aggregate such as coke and heat-conducting agent, and press-form and sinter into a block-shaped material. The method has simple equipment, mature process, and can be used for large-scale manufacturing of carbon-based thermal storage materials.

[0043] In an embodiment of the present disclosure, in step S1, the mixing treatment comprises: mixing the coke and the heat-conducting agent at 120-130℃ and 50-60r / min for 30-60min to obtain a first mixture; mixing the first mixture and the binder at 160-210℃ and 50-60r / min for 15-30min to obtain the raw material mixture. The mixing treatment method provided by the present disclosure can remove the residual moisture in the aggregate such as coke and heat-conducting agent, and fully mix and uniformly mix with the pitch binder in a molten state.

[0044] In an embodiment of the present disclosure, in step S2, the compaction treatment conditions comprise: a forming pressure of 100-130MPa, preferably 130MPa; a forming temperature of 90-95℃, preferably 95℃; and a pressure holding time of 1-3min, preferably 3min. According to the process conditions in this embodiment, especially the preferred process conditions, a thermal storage material with better performance, such as higher friction coefficient and thermal conductivity, can be prepared on the basis of reducing the use of thermal energy.

[0045] In an embodiment of the present disclosure, in step S3, the embedding treatment comprises: filling the voids between the carbon-based thermal storage materials and the voids between the carbon-based thermal storage materials and the furnace chamber with the embedding material (a mixture of quartz sand / metallurgical coke powder, with a weight ratio of 1:1).

[0046] In the present disclosure, the raw green body can be embedded with an embedding material to avoid deformation, cracking or damage of the raw green body caused by the gas and / or liquid generated by the binder; the raw green body can be embedded with the embedding material for roasting treatment to ensure uniform temperature distribution during roasting and effectively promote heat transfer; in addition, the embedding treatment can effectively prevent the raw green body from being oxidized.

[0047] In an embodiment of the present disclosure, the roasting treatment conditions include: a roasting temperature of 800-850℃, preferably 850℃; a roasting time of 1-2h, preferably 2h; and an air atmosphere. The heat storage material prepared according to the roasting conditions in this embodiment, especially the preferred roasting conditions, has better performance, such as higher friction coefficient and thermal conductivity.

[0048] To further obtain a heat storage material with better performance such as friction coefficient and thermal conductivity, preferably, the heating rate for heating to the roasting temperature is 0.3-0.5℃ / min, preferably 0.3℃ / min. The suitable heating rate can prevent the carbon-based heat storage material from cracking due to too fast gas volatilization and uneven heating during roasting, thereby reducing the performance such as friction coefficient, thermal conductivity and strength.

[0049] The third aspect of the present disclosure provides a high-friction-coefficient carbon-based heat storage material prepared by the method of the second aspect, wherein the carbon-based heat storage material has a friction coefficient of 0.52-0.88, preferably 0.52-0.78; a density of 1.47-1.61g / cm -3 , preferably 1.58-1.61g / cm -3 ; a thermal conductivity of 7.2-35.6W / mK, preferably 19.0-35.6W / mK; and a compressive strength of 14.0-18.5MPa, preferably 15.1-16.9MPa.

[0050] The fourth aspect of the present disclosure provides the use of the composition of the first aspect or the high-friction-coefficient carbon-based heat storage material of the third aspect in a heat storage system device in the field of heat storage for heating and / or heat storage for steam production.

[0051] In the present disclosure, the carbon-based heat storage material prepared by the present disclosure can effectively overcome the problem of interlayer slippage of the carbon-based heat storage material and can be widely used in the field of solid heat storage; specifically, in the field of solid heat storage, the carbon-based heat storage material can be used in a heat storage system in the field of heat storage for heating and / or heat storage for steam production, effectively avoiding the problem of slippage during transportation and hoisting of the product, and without the need to increase an additional fixing system during assembly of the heat storage system, achieving the effect of simplifying the system.

[0052] The present disclosure is further illustrated in detail by the following examples. The raw materials used in the examples are all commercially available.

[0053] The specifications of the coke used in the following examples include:

[0054] (1) The coke with a particle size of 200 mesh, with a volatile content of 1.0 wt%, an ash content of 7.8 wt%, and a fixed carbon content of 91.2 wt% based on the total weight of the coke, was purchased from Shanxi Coking Co., Ltd.;

[0055] (2) The coke with an average particle size of 1-3 mm, with a volatile content of 1.2 wt%, an ash content of 10 wt%, and a fixed carbon content of 88.8 wt% based on the total weight of the coke, was purchased from Shanxi Coking Co., Ltd.

[0056] Example 1

[0057] The coke used in this example is a coke with a particle size of 200 mesh;

[0058] The heat-conducting filler is natural graphite (50 mesh, carbon content of 98%, graphitization degree of 99%) and artificial graphite (50 mesh, carbon content of 98%, graphitization degree of 99%);

[0059] The binder is coal tar pitch (softening point of coal tar pitch is 80°C, carbon residue rate is 57 wt%).

[0060] The method for preparing the carbon-based heat storage material includes the following steps:

[0061] (1) Preparation of raw material mixture: sample according to the percentage of total weight (100 grams), wherein the coke: heat-conducting agent: binder = coke: (natural graphite + artificial graphite): pitch = 16.00 wt%: (25.00 wt% + 35.00 wt%): 24.00 wt% (i.e., the weight ratio of coke to heat-conducting agent = 0.27:1);

[0062] First, mix the coke, natural graphite, and artificial graphite in a kneading machine at 120°C and 50 r / min for 30 min, then add the pitch into the kneading machine and mix at 160°C and 50 r / min for 15 min to obtain the raw material mixture, and discharge for standby use.

[0063] (2) Preparation of raw material green body: weigh about 115 g of the raw material mixture and press at a pressure of 130 Mpa at 95°C to obtain the raw material green body, then demold for standby use.

[0064] (3) Embedding: The green body of raw materials is subjected to embedding treatment, and embedding material (a mixture of quartz sand / metallurgical coke powder, a weight ratio of 1:1) is used to fill the gaps between the carbon-based thermal storage materials and the gaps between the carbon-based thermal storage materials and the furnace chamber.

[0065] (4) Calcination: The embedded material is placed in a carbonization furnace for calcination, the target temperature is 850°C, the temperature rising rate to the calcination temperature is 0.3°C / min, and the temperature is kept for 2h, the calcination atmosphere is air, and the material is taken out after cooling to room temperature in the furnace for standby, to obtain the carbon-based thermal storage material.

[0066] Example 2

[0067] According to the preparation method in Example 1, which is different from Example 1, the sample is weighed according to the percentage of the total weight (100g), wherein the coke: heat conductor: binder = coke: (natural graphite + artificial graphite): pitch = 30.00wt%: (18.00wt% + 28.00wt%): 24.00wt% (i.e. the weight ratio of coke to heat conductor = 0.65:1); to obtain the carbon-based thermal storage material.

[0068] Example 3

[0069] According to the preparation method in Example 1, which is different from Example 1, the sample is weighed according to the percentage of the total weight (100g), wherein the coke: heat conductor: binder = coke: (natural graphite + artificial graphite): pitch = 46.00wt%: (10.00wt% + 20.00wt%): 24.00wt% (i.e. the weight ratio of coke to heat conductor = 1.53:1); to obtain the carbon-based thermal storage material.

[0070] Example 4

[0071] According to the preparation method in Example 1, which is different from Example 1, no heat conductor is added, and the sample is weighed according to the percentage of the total weight (100g), wherein the coke: binder = coke: pitch = 76.00wt%: 24.00wt%; to obtain the carbon-based thermal storage material.

[0072] Example 5

[0073] According to the preparation method in Example 4, which is different from Example 4, two specifications of coke are used, and no heat conductor is used, and the sample is weighed according to the percentage of the total weight (100g), wherein the coke: heat conductor: binder = (coke with a particle size of 200 mesh + coke with an average particle size of 1-3mm): pitch = (60.00wt% + 16.00wt%): 24.00wt%, to obtain the carbon-based thermal storage material.

[0074] Example 6

[0075] The preparation method in Example 1 is followed, except that in Example 1, the difference is that two specifications of coke are used, and the sample is weighed in percentage of total weight (100 grams), wherein the coke: heat conductor: binder = (coke with particle size of 200 mesh + coke with average particle size of 1-3 mm): (natural graphite + artificial graphite): pitch = (36.00% by weight + 10.00% by weight): (10.00% by weight + 20.00% by weight): 24.00% by weight (i.e., the weight ratio of coke to heat conductor = 1.53:1); and a carbon-based thermal storage material is obtained.

[0076] Example 7

[0077] The preparation method in Example 1 is followed, except that in Example 1, the difference is that the pitch is used as a mesophase pitch and a non-mesophase pitch, wherein the mesophase pitch is a coal mesophase pitch (190°C, 90% by weight of carbon residue rate); the non-mesophase pitch is a coal pitch (softening point of 80°C, 57% by weight of carbon residue rate); and the weight ratio of the mesophase pitch to the non-mesophase pitch is 0.1:1. The mixing parameters of the pitch after being added to the kneader are adjusted to 195°C, 50 r / min for 5 min. A carbon-based thermal storage material is obtained.

[0078] Example 8

[0079] The preparation method in Example 1 is followed, except that in Example 1, the difference is that in step (1), the coke, natural graphite and artificial graphite are first mixed in the kneader at 130°C, 60 r / min for 60 min, and then the pitch is added to the kneader and mixed at 170°C, 60 r / min for 30 min to obtain a raw material mixture, which is discharged for standby. A carbon-based thermal storage material is obtained.

[0080] Example 9

[0081] The preparation method in Example 1 is followed, except that in Example 1, the difference is that in step (2), the preparation of the raw material green body: about 115 g of the raw material mixture is pressed at a pressure of 100 Mpa at 90°C to obtain a raw material green body, which is then demolded for standby. A carbon-based thermal storage material is obtained.

[0082] Example 10

[0083] The preparation method in Example 1 is followed, except that in Example 1, the difference is that in step (4), the roasting: the embedded material is placed in a carbonization furnace for roasting, the target temperature is 800°C, and the temperature is maintained for 1 h, the roasting atmosphere is air, and the material is taken out after cooling to room temperature in the furnace for standby, to obtain a carbon-based thermal storage material.

[0084] Example 11

[0085] According to the preparation method in Example 1, the difference between Example 1 is that in step (4), the roasting: the embedded material is placed in the carbonization furnace for roasting, the target temperature is 850℃, the temperature rising rate to the roasting target temperature is 0.5℃ / min, and the holding time is 2h, the roasting atmosphere is air, and the material is taken out after cooling to room temperature in the furnace for standby, to obtain the carbon-based thermal storage material.

[0086] Comparative Example 1

[0087] According to the preparation method in Example 1, the difference between Example 1 is that no coke is added, and the sample is weighed according to the percentage of the total weight (100g), wherein the thermal conductive agent: binder = (natural graphite + artificial graphite): pitch = (41.00wt% + 35.00wt%): 24.00wt%, to obtain the carbon-based thermal storage material.

[0088] Comparative Example 2

[0089] Graphite is used as aggregate, and the sample is weighed according to the percentage of the total weight (100g), graphite: 80wt%, pitch: 5wt%, graphene: 15wt%;

[0090] (1-1) 5g of pitch is mixed with 100mL of solvent tetrahydrofuran to obtain a pitch solution, and the mixing temperature is 65℃;

[0091] (1-2) Graphite (carbon content 95wt%, 50 mesh) and graphene (loftiness 300, at least one of the three-dimensional size is ≥100μm, graphitization degree 99%) are added to the pitch solution for second mixing, the mixing temperature is 65℃, the holding time is 15min, and the solvent is removed to obtain a premix;

[0092] (1-3) The premix is molded, the molding temperature is 550℃, the molding pressure is 1000bar, and the molding holding time is 3h. The carbon-based material is prepared.

[0093] Comparative Example 3

[0094] According to the preparation method in Example 1, the difference between Example 1 is that in step (1), the coke, natural graphite and artificial graphite are first mixed in the kneader at 110℃, 40r / min for 10min, then the pitch is added to the kneader, and mixed at 150℃, 40r / min for 10min to obtain the raw material mixture, and the material is discharged for standby. The carbon-based thermal storage material is obtained.

[0095] Comparative Example 4

[0096] The preparation method in example 1, except that in step (2), the preparation of the raw green body: about 115 g of raw material mixture was pressed at 100 ℃ under a pressure of 150 MPa, and the holding time was 10 min, to obtain a raw green body, and then demoulding for standby. The carbon-based thermal storage material was obtained.

[0097] Comparative example 5

[0098] The preparation method in example 1, except that in step (4), baking: the embedded material was placed in a carbonization furnace for baking, the target temperature was 1000 ℃, and the holding time was 3 h, the baking atmosphere was air, and after cooling to room temperature in the furnace, it was taken out for standby, to obtain the carbon-based thermal storage material.

[0099] The raw material content in the composition of the above examples and comparative examples is shown in Table 1.

[0100] Table 1

[0101]

[0102] Test example

[0103] The density, strength and thermal conductivity of the carbon-based thermal storage material prepared in the above examples and comparative examples were tested, and the test results are shown in Table 2 below.

[0104] Among them, the friction coefficient of the high-friction coefficient carbon-based thermal storage material was measured according to GB10006, ASTM D1894 and other test standards;

[0105] The bulk density of the high-friction coefficient carbon-based thermal storage material was measured according to GB / T24528-2009 method;

[0106] The thermal conductivity of the high-friction coefficient carbon-based thermal storage material was measured according to ASTM E1461 method;

[0107] The compressive strength of the high-friction coefficient carbon-based thermal storage material was measured according to GBT1431-2019 method;

[0108] The softening point of the asphalt binder was measured according to GBT4507-2014 asphalt softening point determination method ring ball method.

[0109] Table 2

[0110]

[0111] From Table 2, compared with the thermal storage materials of comparative examples 1 and 2, the carbon-based thermal storage materials prepared in examples 1-11 have significantly higher friction coefficient (0.52-0.88), which can effectively overcome the problem of interlayer slip of carbon-based thermal storage materials.

[0112] Further, the high-friction-coefficient carbon-based thermal storage materials prepared in Examples 1-3 and Examples 6-11 have higher thermal conductivities (19.0-35.6 W / mK), which can meet the application thereof in the field of solid thermal storage.

[0113] Further, compared with the carbon-based thermal storage material of Comparative Example 1, the high-friction-coefficient carbon-based thermal storage materials of Examples 1-7 also have higher compressive strengths.

[0114] Further, compared with the carbon-based thermal storage material of Example 1, the carbon-based thermal storage material prepared in Example 7 has higher compressive strength and density due to the introduction of mesophase pitch with high softening point and high carbon residue as a binder.

[0115] Further, compared with Example 8, the thermal conductivity, density and compressive strength of the thermal storage material prepared in Example 1 are higher than those of Example 8, which may be caused by the aging of pitch and the cracks of the obtained thermal storage material due to the long mixing temperature and mixing time. Compared with Comparative Example 3, the thermal conductivity, density and compressive strength of the thermal storage material prepared in Example 1 are higher than those of Comparative Example 3, which may be because the mixing temperature and mixing time of Comparative Example 3 are too low, resulting in uneven mixing of coke and thermal conductive agent with pitch binder and insufficient wetting degree.

[0116] Further, compared with Example 9, the thermal conductivity, density and compressive strength of the thermal storage material prepared in Example 1 are higher than those of Example 9, which may be because Example 9 adopts a lower compaction temperature and pressure and a shorter compaction time, resulting in insufficient density of the thermal storage material. Compared with Comparative Example 4, the thermal conductivity, density and compressive strength of the thermal storage material prepared in Example 1 are higher than those of Comparative Example 4, which may be because Comparative Example 4 adopts a higher compaction temperature and pressure and a longer compaction time, resulting in aging of pitch and cracks of the thermal storage material.

[0117] Further, compared with Example 10, the thermal conductivity, density and compressive strength of the thermal storage material prepared in Example 1 are higher than those of Example 10, which may be because Example 10 uses a lower calcination temperature and a shorter calcination time, resulting in low carbonization degree of the pitch binder. Compared with Comparative Example 5, the thermal conductivity, density and compressive strength of the thermal storage material prepared in Example 1 are higher than those of Comparative Example 5, which may be because Comparative Example 5 adopts a higher calcination temperature and a longer calcination time, resulting in oxidation side reactions of the thermal storage material.

[0118] Further, compared with Example 11, the thermal conductivity, density and compressive strength of the thermal storage material prepared in Example 1 are higher than those of Example 11, which may be because Example 11 adopts a higher heating rate, resulting in rapid gas production during the reaction, stress concentration and cracks of the thermal storage material.

[0119] The preferred embodiments of the present disclosure are described in detail above, but the present disclosure is not limited to the specific details described in the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

[0120] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present disclosure.

[0121] In addition, various different embodiments of the present disclosure can also be combined in any manner as long as they do not deviate from the idea of the present disclosure, and they should also be considered as disclosed by the present disclosure.

Claims

1. A method of producing a carbon-based heat storage material with a high coefficient of friction, characterized by, The method comprises the following steps: S1, mixing the carbon-based heat storage material with a composition to obtain a raw material mixture; S2, performing a molding treatment on the raw material mixture to obtain a raw material green body; S3, performing embedding treatment and sintering treatment on the raw material green body; The composition comprises 16-46 wt% of coke, 30-60 wt% of a heat-conducting agent and 22-26 wt% of a binder, based on the total weight of the composition; The coke has a volatile content of 1.0-1.2 wt%, an ash content of 7.8-10 wt% and a fixed carbon content of 88.8-91.2 wt%, based on the total weight of the coke; The heat-conducting agent is a graphite material, and the binder is pitch; In step S1, the mixing treatment comprises mixing the coke and the heat-conducting agent at 120-130℃ and 50-60r / min for 30-60min to obtain a first mixture, and mixing the first mixture and the binder at 160-210℃ and 50-60r / min for 15-30min to obtain the raw material mixture; In step S2, the molding treatment is performed under the following conditions: The molding pressure is 100-130MPa, the molding temperature is 90-95℃, and the pressure holding time is 1-3min; In step S3, the sintering treatment is performed under the following conditions: the sintering temperature is 800-850℃, the sintering time is 1-2h, the sintering atmosphere is air, and the heating rate for heating to the sintering temperature is 0.3-0.5℃ / min.

2. The method of claim 1, wherein, In the composition, the weight ratio of the coke to the heat-conducting agent is (0.26-1.54):

1.

3. The method of claim 2, wherein, The coke has an average particle size of 0.075-3mm; The graphite material has an average particle size of 50-200mesh, a carbon content of 95-98% and a graphitization degree of 98-99%, and is selected from one or more of natural flake graphite, graphitized petroleum coke, graphitized needle coke and graphite electrode broken material; The binder is pitch.

4. The method of claim 3, wherein, The graphite material is natural flake graphite and / or graphitized petroleum coke; The pitch is selected from mesophase pitch and / or non-mesophase pitch; the mesophase pitch has a softening point of 175-200℃ and a carbon residue rate of 80-95wt%, and the non-mesophase pitch has a softening point of 75-95℃ and a carbon residue rate of 55-60wt%.

5. The method of claim 4, wherein, The mesophase pitch is selected from one or more of coal mesophase pitch, petroleum mesophase pitch and pure aromatic mesophase pitch, and the non-mesophase pitch is selected from coal pitch and / or petroleum pitch.

6. The method of claim 5, wherein, The weight ratio of the mesophase pitch to the non-mesophase pitch is 0.1:(0-1).

7. The high-friction carbon-based heat storage material produced by the method according to any one of claims 1 to 6, characterized by The carbon-based heat storage material has a friction coefficient of 0.52-0.88, a density of 1.47-1.61 g / cm 3 , a thermal conductivity of 7.2-35.6 W / mK, and a compressive strength of 14.0-18.5 MPa.

8. The carbon-based thermal storage material of claim 7, wherein, The carbon-based heat storage material has a friction coefficient of 0.52-0.78; a density of 1.58-1.61 g / cm 3 ; a thermal conductivity of 19.0-35.6 W / mK; and a compressive strength of 15.1-16.9 MPa.

9. Use of the carbon-based heat storage material with high friction coefficient according to any one of claims 7-8 in a heat storage system in the field of heat storage heating and / or heat storage steam generation.

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