Hydrophilic Modified Grinding Aids and Pre-treatment Process for Nanogrinding of Nano Hydrocarbon Fuel

Abstract

The present invention provides a hydrophilic modified grinding aid and a pre - process for nano - pulverizing nano - hydrocarbon fuel. The hydrophilic modified grinding aid provided by the present invention comprises 20% - 40% of sodium fatty acid, 35% - 60% of sodium hexametaphosphate and 5% - 25% of titanium dioxide. The hydrophilic modified grinding aid provided by this application synergistically interacts with the hydrophobic regions on the surface of coal powder particles through the specific mass ratio of sodium fatty acid, sodium hexametaphosphate and titanium dioxide. On the one hand, it can interact with the hydrophobic regions on the surface of coal powder particles, and on the other hand, it can combine with water molecules, converting the highly hydrophobic surface of coal powder into a hydrophilic surface, making the coal powder particles easier to be wetted by water, reducing the interfacial contact angle between the coal powder particles and water. At the same time, it can form a hydration film on the surface of coal powder particles to prevent the aggregation of coal powder particles, making the coal powder particles uniformly dispersed in water, reducing the viscosity of the slurry and improving the fluidity, thereby effectively improving the pulverization efficiency, reducing the energy consumption per unit product and increasing the production efficiency of nano - hydrocarbon fuel.

Description

Technical Field

[0001] The present invention relates to the technical field of grinding aids, and in particular, to a hydrophilic modified grinding aid and a pre - process for nano - pulverizing nano - hydrocarbon fuel. Background Art

[0002] Nano - hydrocarbon fuel is a new type of ultra - fine particle fuel developed by using industrial nano - powder production technology and other supporting processes to process coal. It has a high specific surface area and surface activity, and has the characteristics of high combustion efficiency and low pollutant emissions. It is a high - efficiency and clean new type of coal - based special fuel.

[0003] In the process of preparing nano - hydrocarbon fuel, after coal powder is ultra - finely pulverized to the micron level, the specific surface area and surface energy of coal powder particles increase sharply, the agglomeration phenomenon intensifies, and due to the strong hydrophobicity of the coal powder surface, the coal powder particles cannot be closely combined with water to form an integrated slurry. Even when the concentration is high, a "mud mass" - like structure will be formed, which will cause a large mechanical resistance, resulting in a high viscosity and poor fluidity of the slurry, hindering the normal operation of the equipment, significantly reducing the pulverization efficiency, and significantly increasing the energy consumption per unit product.

[0004] Adding a suitable grinding aid is one of the methods to improve the pulverization efficiency of coal powder and reduce energy consumption. The ultra - fine pulverization process is not only a simple physical process of reducing particle size, but also involves changes in the physical and chemical properties of coal powder particles caused by mechanical ultra - fine pulverization. Existing technologies have studied the mechanochemical effect in the ultra - fine pulverization process more, but the influence of the physical and chemical property changes of coal powder particles on the selection of grinding aids and processing efficiency in the ultra - fine pulverization process is almost blank.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The main object of the present invention is to provide a hydrophilic modified grinding aid and a pre - process for nano - pulverizing nano - hydrocarbon fuel to solve the technical problems of low pulverization efficiency and high energy consumption per unit product existing in the existing ultra - fine pulverization process of coal powder.

[0007] To achieve the above object, according to one aspect of the present invention, a hydrophilic modified grinding aid is provided. The hydrophilic modified grinding aid comprises 20% - 40% of sodium fatty acid, 35% - 60% of sodium hexametaphosphate, and 5% - 25% of titanium dioxide.

[0008] Further, in the above - mentioned hydrophilic modified grinding aid, the mass content of sodium fatty acid is 30% - 40%, the mass content of sodium hexametaphosphate is 50% - 60%, and the mass content of titanium dioxide is 5% - 15%.

[0009] Further, in the above hydrophilic modified grinding aid, the mass content of sodium fatty acid is 35%, the mass content of sodium hexametaphosphate is 55%, and the mass content of titanium dioxide is 10%.

[0010] Further, the titanium dioxide is anatase titanium dioxide, and the particle size D50 of the titanium dioxide is 50 - 200 nm.

[0011] According to another aspect of the present invention, there is also provided a pre - process for nano - grinding of nano - hydrocarbon fuel. The pre - process includes: mixing coal slurry and a grinding aid to obtain a modified raw material for preparing nano - hydrocarbon fuel, wherein the grinding aid is any one of the hydrophilic modified grinding aids provided in the first aspect above.

[0012] Further, the above - mentioned mixing method includes at least one of ultrasonic and stirring.

[0013] Further, the above - mentioned mixing includes: first, ultrasonic dispersion for 5 - 15 min, and then stirring for 15 - 30 min.

[0014] Further, the power of the above - mentioned ultrasonic dispersion is 20 - 80 kHz, and the rotation speed of stirring is 5000 - 15000 revolutions per minute.

[0015] Further, the above - mentioned coal slurry includes coal powder particles and water. In the coal slurry, the mass content of coal powder particles is 20% - 40%, preferably 25%.

[0016] Further, the dosage ratio of the grinding aid to the coal powder particles is 0.5 - 5:1000, preferably 1:1000.

[0017] Further, the particle size D50 of the coal powder particles is 10 - 100 μm.

[0018] Further, the coal powder particles are obtained by crushing raw coal. The raw material includes the following components by mass percentage: carbon 63% - 65%, alumina 13% - 15%, silica 8% - 10%, calcium oxide 1.5% - 2.0%, and iron oxide 1.0% - 2.0%.

[0019] The hydrophilic modified grinding aid provided in this application synergistically combines sodium fatty acid, sodium hexametaphosphate, and titanium dioxide with specific mass ratios. On the one hand, it can interact with the hydrophobic region on the surface of coal powder particles, and on the other hand, it can combine with water molecules. It can not only convert the surface of strongly hydrophobic coal powder particles into hydrophilicity, making the coal powder particles easier to be wetted by water, reducing the interfacial contact angle between the coal powder particles and water, but also form a hydration film on the surface of the coal powder particles to block the aggregation of coal powder particles, making the coal powder particles evenly dispersed in water, reducing the slurry viscosity, improving the fluidity, thereby effectively improving the grinding efficiency, reducing the energy consumption per unit product, and improving the production efficiency of nano - hydrocarbon fuel. Detailed implementation manners

[0020] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0021] As analyzed in the background art of this application, there are technical problems of low pulverization efficiency and high energy consumption per unit product in the existing pulverized coal ultra-fine pulverization process. To solve this problem, this application provides a preparation method of a hydrophilic modified grinding aid and a nano hydrocarbon fuel.

[0022] In a typical implementation manner of this application, a hydrophilic modified grinding aid is provided. By mass percentage, the hydrophilic modified grinding aid includes 20% - 40% of sodium fatty acid, 35% - 60% of sodium hexametaphosphate, and 5% - 25% of titanium dioxide.

[0023] The hydrophilic modified grinding aid provided by this application synergistically combines sodium fatty acid, sodium hexametaphosphate, and titanium dioxide with specific mass ratios. On the one hand, it can interact with the hydrophobic region on the surface of pulverized coal, and on the other hand, it can combine with water molecules. It can not only convert the surface of pulverized coal with strong hydrophobicity into hydrophilicity, making the pulverized coal particles easier to be wetted by water, reducing the interfacial contact angle between the pulverized coal particles and water, but also form a hydration film on the surface of the pulverized coal particles to prevent the aggregation of pulverized coal particles, making the pulverized coal particles evenly dispersed in water, reducing the slurry viscosity, improving the fluidity, and thus effectively improving the pulverization efficiency, reducing the energy consumption per unit product, and improving the preparation efficiency of the nano hydrocarbon fuel.

[0024] The general formula of the above sodium fatty acid is RCOONa, where R is a saturated or unsaturated alkyl group with 11 - 18 carbon atoms; the above sodium fatty acid includes, but is not limited to, any one or a mixture of multiple of sodium laurate, sodium myristate, sodium palmitate, sodium stearate, sodium palmitoleate, and sodium linolenate.

[0025] The type of the above titanium dioxide is not limited. When anatase titanium dioxide is preferably used, the hydrophilic modified grinding aid composed of it has a more significant grinding effect on pulverized coal. To further improve the grinding effect, it is preferred that the particle size D50 of the above titanium dioxide is 50 - 200 nm.

[0026] Typically but not limitedly, in the hydrophilic modified grinding aid provided in the present application, the mass content of sodium fatty acid is, for example, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40% or a range composed of any two of these numbers; the mass content of sodium hexametaphosphate is, for example, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58%, 60% or a range composed of any two of these numbers; the mass content of titanium dioxide is, for example, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25% or a range composed of any two of these numbers; the particle size D50 of titanium dioxide is, for example, 50nm, 80nm, 100nm, 120nm, 150nm, 180nm, 200nm or a range composed of any two of these numbers.

[0027] In order to further improve the efficiency of nano-grinding of pulverized coal and further reduce the energy consumption per unit product, in some embodiments of the present application, in the above-mentioned hydrophilic modified grinding aid, the mass content of sodium fatty acid is 30% - 40%, the mass content of sodium hexametaphosphate is 50% - 60%, and the mass content of titanium dioxide is 5% - 15%. Especially when the mass content of sodium fatty acid in the hydrophilic modified grinding aid is 35%, the mass content of sodium hexametaphosphate is 55%, and the mass content of titanium dioxide is 10%, after it is mixed with the coal slurry, the nano-grinding efficiency is higher.

[0028] In the second typical embodiment of the present application, a pre-treatment process for nano-grinding of nano-hydrocarbon fuel is further provided. The pre-treatment process includes: mixing the coal slurry and the grinding aid to obtain a modified raw material for preparing nano-hydrocarbon fuel, where the grinding aid is any one of the hydrophilic modified grinding aids provided in the first typical embodiment above.

[0029] The above-mentioned coal slurry contains solid substances and water. The solid substances are mainly pulverized coal particles, and the solid substances may also include additives. Considering that the content of additives in the solid substances is very low and can be ignored, the mass content of pulverized coal particles in the present application is the mass content of solid substances in the coal slurry.

[0030] Applying the technical solution of the present application, during the preparation of nano-hydrocarbon fuel, mixing the above-provided hydrophilic modified grinding aid with the coal slurry. On the one hand, the hydrophilic modified grinding aid interacts with the hydrophobic region on the surface of pulverized coal particles, and on the other hand, combines with water, making the pulverized coal particles easier to be wetted by water. At the same time, a hydration film that blocks the aggregation of pulverized coal particles is formed on the surface of the pulverized coal particles, so that the pulverized coal particles can be evenly distributed in water, effectively reducing the viscosity of the slurry and improving the fluidity, thereby effectively improving the grinding efficiency, reducing the energy consumption per unit product, and improving the preparation efficiency of nano-hydrocarbon fuel.

[0031] The above-mentioned coal slurry is mainly obtained by dispersing coal powder particles in water. In order to further improve the efficiency of subsequent nano-grinding treatment, it is preferred that in the coal slurry, the mass content of coal powder particles is 20% - 40%. Especially when the mass content of coal powder particles in the coal slurry is 25%, it is more conducive to cooperating with the grinding aid to improve the nano-grinding treatment efficiency. In order to further improve the grinding efficiency of subsequent nano-hydrocarbon fuel, it is preferred that the dosage ratio of the above-mentioned grinding aid to coal powder particles is 0.5 - 5:1000. Especially when the dosage ratio of the grinding aid to coal powder particles is 1:1000, the preparation efficiency of nano-hydrocarbon fuel is higher.

[0032] Typical but non-limiting, in the above-mentioned coal slurry, the mass content of coal powder particles is, for example, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40% or a range value composed of any two numerical values; the dosage ratio of the grinding aid to coal powder particles is 0.5:1000, 0.8:1000, 1:1000, 1.2:1000, 1.5:1000, 1.8:1000, 2:1000, 2.5:1000, 3:1000, 3.5:1000, 4:1000, 4.5:1000, 5:1000 or a range composed of any two numbers; in the above-mentioned coal slurry, the particle size D50 of coal powder particles is, for example, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 100μm or a range value composed of any two numerical values.

[0033] In order to further improve the efficiency of subsequent nano-hydrocarbon fuel grinding, preferably, in order to further improve the mixing efficiency of the coal slurry and the grinding aid, the above mixing includes at least one of ultrasonic and stirring. In some preferred embodiments of the present application, the above mixing includes: first, ultrasonic dispersion for 5 - 15 min, and then stirring for 15 - 30 min, so as to facilitate the rapid and uniform mixing of the grinding aid and the coal slurry, and further improve the mixing efficiency.

[0034] In order to further improve the efficiency of the above-mentioned grinding aid dispersion treatment, it is preferred that the ultrasonic dispersion power is 20 - 80 kHz, and the rotation speed of the above stirring is 5000 - 15000 revolutions per minute.

[0035] There is no limitation on the equipment for the above ultrasonic dispersion, including but not limited to ultrasonic generators with a power of 0.5 - 5 kW; there is also no limitation on the equipment for the above stirring, including but not limited to mixers with a power of 0.5 - 5 kW.

[0036] Typically but not limited to, in the above step S2, if the power of ultrasonic dispersion is 20 kHz, 30 kHz, 40 kHz, 50 kHz, 60 kHz, 70 kHz, 80 kHz or a range composed of any two numbers, and the time of ultrasonic dispersion is, for example, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 12 min, 15 min or a range composed of any two numbers; the rotation speed of stirring is, for example, 5000 r / min, 8000 r / min, 10000 r / min, 12000 r / min, 15000 r / min or a range composed of any two numbers, and the time of stirring is, for example, 15 min, 18 min, 20 min, 22 min, 25 min, 28 min, 30 min or a range composed of any two numbers.

[0037] The beneficial effects of the present application will be further described below in conjunction with examples and comparative examples.

[0038] Example 1

[0039] This example provides a hydrophilic modified grinding aid. By mass percentage, the hydrophilic modified grinding aid includes 35% sodium fatty acid, 55% sodium hexametaphosphate and 10% titanium dioxide. Among them, the sodium fatty acid is purchased from Sinopharm Group Pharmaceutical Co., Ltd., the titanium dioxide is anatase titanium dioxide, and the particle size D50 of the titanium dioxide is 50 - 200 nm.

[0040] Example 2

[0041] This example provides a hydrophilic modified grinding aid, which is different from Example 1 in that the mass content of sodium fatty acid is 20%, the mass content of sodium hexametaphosphate is 60%, and the mass content of titanium dioxide is 20%.

[0042] Example 3

[0043] This example provides a hydrophilic modified grinding aid, which is different from Example 1 in that the mass content of sodium fatty acid is 40%, the mass content of sodium hexametaphosphate is 35%, and the mass content of titanium dioxide is 25%.

[0044] Example 4

[0045] This example provides a hydrophilic modified grinding aid, which is different from Example 1 in that the mass content of sodium fatty acid is 30%, the mass content of sodium hexametaphosphate is 55%, and the mass content of titanium dioxide is 15%.

[0046] Example 5

[0047] This embodiment provides a hydrophilic modified grinding aid, which is different from that of Embodiment 1 in that the mass content of sodium fatty acid is 35%, the mass content of sodium hexametaphosphate is 60%, and the mass content of titanium dioxide is 5%.

[0048] Comparative Example 1

[0049] This comparative example provides a grinding aid, which is different from that of Embodiment 1 in that it does not contain titanium dioxide, and the mass content of sodium fatty acid is 39%, and the mass content of sodium hexametaphosphate is 61%.

[0050] Comparative Example 2

[0051] This comparative example provides a grinding aid, which is different from that of Embodiment 1 in that it does not contain sodium fatty acid, and the mass content of sodium hexametaphosphate is 80%, and the mass content of titanium dioxide is 20%.

[0052] Comparative Example 3

[0053] This comparative example provides a grinding aid, which is different from that of Embodiment 1 in that it does not contain sodium hexametaphosphate, and the mass content of sodium fatty acid is 75%, and the mass content of titanium dioxide is 25%.

[0054] Comparative Example 4

[0055] This comparative example provides a grinding aid, which is different from that of Embodiment 1 in that the mass content of sodium fatty acid is 60%, and the mass content of sodium hexametaphosphate is 35%.

[0056] Comparative Example 5

[0057] This comparative example provides a grinding aid, which is different from that of Embodiment 1 in that the mass content of sodium fatty acid is 15%, and the mass content of titanium dioxide is 30%.

[0058] The grinding aids provided in the above embodiments and comparative examples are all prepared by mixing various raw materials.

[0059] Embodiment 6

[0060] This embodiment provides a pre - process for nano - pulverizing nano - hydrocarbon fuel, including the following steps:

[0061] Mix the coal slurry and the hydrophilic grinding aid provided in Example 1 under mechanical stirring. First, perform ultrasonic dispersion at a power of 50 kHz for 10 min, and then stir at 10,000 revolutions per minute for 25 min for dispersion treatment to obtain a modified raw material for preparing nano hydrocarbon fuel; wherein, the mass content of the solid substance in the coal slurry is 25%, the mass ratio of the grinding aid to the solid substance is 1‰, the solid substance includes pulverized coal particles, the particle size of the pulverized coal particles is 10 - 100 nm, which is obtained by pulverizing raw coal, and the raw coal includes the following components by mass percentage: 63% - 65% carbon, 13% - 15% alumina, 8% - 10% silica, 1.5% - 2.0% calcium oxide, and 1.0% - 2.0% iron oxide.

[0062] Examples 7 - 10

[0063] Examples 7 - 10 respectively provide a pre - process for nano - pulverization of hydrocarbon fuel. The differences from Example 6 are that the grinding aids provided in Examples 2 - 5 are respectively used to replace the grinding aid provided in Example 1.

[0064] Example 11

[0065] This example provides a pre - process for nano - pulverization of hydrocarbon fuel. The difference from Example 6 is that in step (2), the addition amount of the grinding aid is 0.5‰ of the mass of the pulverized coal particles.

[0066] Example 12

[0067] This example provides a pre - process for nano - pulverization of hydrocarbon fuel. The difference from Example 6 is that in step (2), the addition amount of the grinding aid is 5‰ of the mass of the pulverized coal particles.

[0068] Example 13

[0069] This example provides a pre - process for nano - pulverization of hydrocarbon fuel. The difference from Example 6 is that in step (2), the addition amount of the grinding aid is 8‰ of the mass of the pulverized coal particles.

[0070] Example 14

[0071] This example provides a pre - process for nano - pulverization of hydrocarbon fuel. The difference from Example 6 is that in step (2), the addition amount of the grinding aid is 0.2‰ of the mass of the pulverized coal particles in the coal slurry.

[0072] Comparative Examples 6 - 10

[0073] Comparative Examples 6 - 10 respectively provide a pre - process for nano - pulverization of hydrocarbon fuel. The differences from Example 6 are that the grinding aids provided in Comparative Examples 1 - 5 are respectively used to replace the grinding aid provided in Example 1.

[0074] Comparative Example 11

[0075] This comparative example provides a pre - process for nano - pulverizing hydrocarbon fuels, which is different from Example 6 in that no grinding aid is added.

[0076] Test Example

[0077] Put the modified raw materials for preparing nano - hydrocarbon fuels provided in the above Examples 6 - 14 and Comparative Examples 6 - 11 into a nano - pulverizer for nano - pulverization. Detect the particle size of the pulverized coal particles at different time points. The results are shown in Table 1 below, where the sampling time refers to the timing time starting from when the nano - pulverizer is started for nano - pulverization.

[0078] Table 1

[0079]

[0080]

[0081]

[0082] From the above description, it can be seen that the above - mentioned embodiments of the present invention achieve the following technical effects:

[0083] The hydrophilic - modified grinding aid provided in this application synergistically combines sodium fatty acid, sodium hexametaphosphate and titanium dioxide with specific mass ratios. On the one hand, it can interact with the hydrophobic regions on the surface of coal - powder particles, and on the other hand, it can combine with water molecules. It can not only convert the surface of coal - powder particles with strong hydrophobicity into hydrophilicity, making the coal - powder particles easier to be wetted by water, reducing the interfacial contact angle between the coal - powder particles and water, but also form a hydration film on the surface of the coal - powder particles to prevent the aggregation of coal - powder particles, making the coal - powder particles evenly dispersed in water, reducing the slurry viscosity, improving the fluidity, and thus effectively improving the pulverization efficiency, reducing the energy consumption per unit product, and improving the production efficiency of nano - hydrocarbon fuels.

[0084] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A hydrophilic modified grinding aid for the pre - process of nano - pulverizing nano - hydrocarbon fuel, characterized in that, by mass percentage, the hydrophilic modified grinding aid comprises 20% - 40% of sodium fatty acid, 35% - 60% of sodium hexametaphosphate and 5% - 25% of titanium dioxide; the titanium dioxide is anatase titanium dioxide, and the particle size D50 of the titanium dioxide is 50 - 200 nm.

2. The hydrophilic modified grinding aid for the pre - process of nano - pulverizing nano - hydrocarbon fuel according to claim 1, characterized in that, in the hydrophilic modified grinding aid, the mass content of the sodium fatty acid is 30% - 40%, the mass content of the sodium hexametaphosphate is 50% - 60%, and the mass content of the titanium dioxide is 5% - 15%.

3. The hydrophilic modified grinding aid for the pre - process of nano - pulverizing nano - hydrocarbon fuel according to claim 1, characterized in that, in the hydrophilic modified grinding aid, the mass content of the sodium fatty acid is 35%, the mass content of the sodium hexametaphosphate is 55%, and the mass content of the titanium dioxide is 10%.

4. A pre - process of nano - pulverizing nano - hydrocarbon fuel, characterized in that, the pre - process includes: mixing coal slurry and a grinding aid to obtain a modified raw material for preparing nano - hydrocarbon fuel, wherein the grinding aid is the hydrophilic modified grinding aid for the pre - process of nano - pulverizing nano - hydrocarbon fuel according to any one of claims 1 to 3.

5. The pre - process according to claim 4, characterized in that, the mixing method includes at least one of ultrasonic and stirring.

6. The pre - process according to claim 5, characterized in that, the mixing includes: first, ultrasonic dispersion for 5 - 15 min, and then stirring for 15 - 30 min.

7. The pre - process according to claim 6, characterized in that, the power of the ultrasonic dispersion is 20 - 80 kHz, and the rotation speed of the stirring is 5000 - 15000 revolutions per minute.

8. The pre - process according to claim 4, characterized in that, the coal slurry includes coal powder particles and water, and in the coal slurry, the mass content of the coal powder particles is 20% - 40%.

9. The pre - process according to claim 8, characterized in that, the mass content of the coal powder particles is 25%.

10. The pre - process according to claim 8, characterized in that, the dosage ratio of the grinding aid to the coal powder particles is 0.5 - 5:1000.

11. The pre - process according to claim 8, characterized in that, the dosage ratio of the grinding aid to the coal powder particles is 1:1000.

12. The pre - process according to claim 8, characterized in that, the particle size D50 of the coal powder particles is 10 - 100 μm.

13. The pre - process according to any one of claims 8 to 12, characterized in that, the coal powder particles are obtained by pulverizing raw coal, and the raw coal comprises the following components by mass percentage: 63% - 65% of carbon, 13% - 15% of alumina, 8% - 10% of silica, 1.5% - 2.0% of calcium oxide, and 1.0% - 2.0% of iron oxide.

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