Method for purifying coal-based heavy oil

Abstract

The invention provides a coal-based heavy oil purification method which comprises the following steps: S1, adding a diluent into a coal-based heavy oil raw material, and heating until the temperature reaches 60-200 DEG C; s2, adding a purifying agent, a viscosity reducer and a dispersing agent, and stirring and mixing to form a coal-based heavy oil intermediate material; and S3, dehydrating the coal-based heavy oil intermediate material, and filtering and purifying to obtain purified coal-based heavy oil. The coal-based heavy oil purification method can realize removal of metal, ash and other impurities in the coal-based heavy oil, effectively reduces the metal content and solid content of the coal-based heavy oil, greatly reduces the processing difficulty of the purified coal-based heavy oil, widens the application field, and is simple in process, easy to operate and suitable for industrial production. And a large amount of coal chemical industry wastewater is not additionally generated.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal-based heavy oil processing. Specifically, the present invention relates to a method for purifying coal-based heavy oil. Background Art

[0002] Coal-based heavy oils such as high-temperature coal tar, medium-low temperature coal tar, gasification tar, and coal direct liquefaction oil usually have the characteristics of high metal content, many solid impurities, and high gum and asphaltene content, which bring great difficulties to subsequent processing. Usually, the oil needs to be purified before further processing and utilization.

[0003] Taking medium-temperature coal tar as an example: Medium-temperature coal tar is usually used to produce light oil products and chemicals through fixed-bed hydrogenation technology. However, the content of impurities such as moisture, metals, active oxygen-containing compounds, and solid particles in coal tar is high. These impurities will have a serious impact on the stable operation of the hydrogenation unit, the activity of the catalyst, and the product quality. Water will cause fluctuations in the operating temperature of the heating furnace and increase energy consumption. Steam will cause serious pulverization of the catalyst and reduce the hydrogenation activity. The metals in coal tar are mainly elements such as Fe, Ca, Al, Na, Mg, and K. During the hydrogenation reaction, most of these metals are removed in the form of sulfides in the pretreatment reactor and deposited in the pores of the pretreatment catalyst and between the catalyst particles, resulting in blockage of the catalyst pore openings, coverage of the active centers, and an increase in the pressure drop of the catalyst bed layer, affecting the long-term operation of the unit. The solid impurity particles are mainly coal powder, coke powder, and mechanical impurities. These solid particles will cause serious blockage of the hydrogenation equipment, pipelines, and catalyst bed layer.

[0004] Taking coal liquefaction residue as an example: Using coal direct liquefaction main by-product - coal liquefaction residue to prepare mesophase pitch, and then manufacturing high-performance carbon fiber, needle coke, lithium battery anode material and other high-end carbon material raw materials. The deashing and refining technology of coal liquefaction residue is the key link and a technical bottleneck that is difficult to break through in the preparation of high-end carbon materials, and it is also an important part of the development of coal liquefaction process technology and the extension of the industrial chain.

[0005] Currently, the commonly used separation and purification methods mainly include sedimentation separation, centrifugal separation, electric field purification (electrodesalting and dehydration device), chemical separation, solvent extraction, hydrocyclone separation, filtration separation, and other separation methods.

[0006] Among them, related technology CN100999675A and related technology CN102079983A both disclose a method for removing impurities in coal tar by using electric field purification (electrodesalting and dehydration device), that is, injecting a certain amount of fresh water into coal tar, fully mixing, and under the action of a demulsifier and a high-voltage electric field, making tiny water droplets aggregate into larger water droplets, and then using the density difference to separate oil and water to achieve the purpose of desalting and dehydration. However, this method will produce a large amount of coal chemical wastewater, and due to the emulsification problem, the purification is difficult, and the impurity removal cannot be well achieved.

[0007] The related technology CN106398735A discloses a method for coal tar pretreatment. In this method, water, salt, and demulsifier are injected into coal tar. After mixing, oil-water separation is carried out, and the coal tar is divided into oil on the water and oil under the water, which are respectively filtered to remove solid impurities, and finally the oil under the water is pickled and washed with water. This method has a complex process flow, and uses a filtering device with a pore size of 0.1 - 1.0 μm, which has high precision and a large investment cost.

[0008] The above purification methods and technologies all have defects such as poor separation effect, low efficiency, and complex process. Moreover, they do not consider the property characteristics of high oxygen content and high phenol content in coal-based heavy oil, resulting in problems such as difficult actual operation and unsatisfactory purification effect, and cannot meet the quality requirements of subsequent hydrogenation units and catalysts for coal-based heavy oil. Summary of the Invention

[0009] The present invention is a filtering and purification method developed based on the fact that coal-based heavy oil cannot be effectively processed and utilized due to its high metal content and high solid content, aiming to effectively reduce the metal content and solid content of coal-based heavy oil to reduce the processing difficulty of coal-based heavy oil.

[0010] To achieve the above object, an embodiment of the present invention provides a purification method for coal-based heavy oil, including the following steps:

[0011] S1, adding a diluent to the coal-based heavy oil raw material and heating it up until the temperature reaches 60 - 200 °C;

[0012] S2, adding a purification agent, a viscosity reducer, and a dispersant, and stirring and mixing to form an intermediate material of coal-based heavy oil;

[0013] S3, dehydrating the intermediate material of coal-based heavy oil and then performing filtration and purification to obtain purified coal-based heavy oil.

[0014] In the embodiment of the present invention, by adding a diluent, a purification agent, a viscosity reducer, and a dispersant to the coal-based heavy oil raw material containing a large amount of impurities such as metals and ash, on the one hand, the oil-soluble metals in the coal-based heavy oil raw material can contact and react with the purification agent at the oil-water interface, causing metal ions to ionize or form precipitates and chelates, and thus the oil-soluble metals can be separated; on the other hand, by introducing a diluent, a viscosity reducer, and a dispersant into the purification system, the viscosity of the system can also be reduced, enabling macromolecules such as resins and asphaltenes in the coal-based heavy oil raw material to be effectively dispersed, and thus it is easier to filter and separate the metals and ash in the coal-based heavy oil raw material, and it is not easy to be blocked. Moreover, the processing and utilization difficulty of the purified coal-based heavy oil is reduced, and its application is more extensive.

[0015] In some embodiments, the diluent includes at least one of naphtha, diesel oil, wash oil, benzene, xylene, toluene, tetrahydrofuran, N-methylpyrrolidone, solvent oil 100#, and solvent oil 150#.

[0016] In some embodiments, the weight ratio of the diluent to the coal-based heavy oil raw material is 0.01:1 to 10:1.

[0017] In some embodiments, the purifying agent includes at least one of formic acid, acetic acid, citric acid, phosphoric acid, carboxylate, phosphate, ethylenediaminetetraacetic acid, and ethylenediaminetetraacetic acid derivatives;

[0018] and / or, the viscosity reducer includes at least one of polyoxyethylene nonylphenol ether-10, sodium dodecylbenzenesulfonate, sodium octadecanoate, sodium dodecyl nonylphenol ether sulfate-10, sodium dodecyl nonylphenol ether ethyl sulfonate-4, carboxymethyl dodecyl nonylphenol ether-10, and α-olefin sulfonate;

[0019] and / or, the dispersant includes at least one of clay, diatomite, kaolin, polycarbonol polyether phosphate, and polycarboxylic acid higher alcohol ester.

[0020] In some embodiments, the weight ratio of the purifying agent, the viscosity reducer, and the dispersant is (1 to 100):(1 to 100):(1 to 100).

[0021] In some embodiments, the weight of the purifying agent is 0.01% to 1% of the weight of the coal-based heavy oil raw material, preferably 0.05% to 0.5%.

[0022] In some embodiments, the time for stirring and mixing is 30 to 90 min.

[0023] In some embodiments, the method of filtration and purification includes at least one of pressure filtration, atmospheric pressure filtration, clay filtration, sedimentation separation, and hydrocyclone separation.

[0024] In some embodiments, the coal-based heavy oil raw material includes at least one of coal liquefied oil, coal tar, coal liquefaction residue, and coal-based asphalt.

[0025] The advantages and positive effects of the present invention are as follows:

[0026] (1) The operation of the present invention is simple, the removal of impurities is efficient, and it is environmentally friendly.

[0027] (2) The present invention adopts the combined technology of diluent, purifying agent, viscosity reducer, and dispersant, which is conducive to the formation of precipitates and chelates of fine particles in coal-based heavy oil and then removal. The removal rate of inorganic minerals is high, the ash content of the product after solid-liquid separation is low, and the purification effect is good.

[0028] (3) The solid residue generated by the present invention can be co-fired with coal, avoiding the discharge of solid waste. Description of the Drawings

[0029] Figure 1 It is a flowchart of the coal-based heavy oil purification method according to an embodiment of the present invention. Detailed Embodiments

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the art to which the present invention pertains.

[0032] In this article, when a value is described as a range, it should be understood that such disclosure includes the disclosure of all possible sub-ranges within that range, as well as the specific values falling within that range, regardless of whether the specific values or specific sub-ranges are explicitly indicated.

[0033] In this article, the term "and / or" is merely a description of the associated relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone.

[0034] As Figure 1 shown, an embodiment of the present invention provides a method for purifying coal-based heavy oil, including the following steps:

[0035] S1, adding a diluent to the coal-based heavy oil raw material and heating it up until the temperature reaches 60 - 200 °C;

[0036] S2, adding a purifying agent, a viscosity reducer, and a dispersant, and stirring and mixing to form an intermediate coal-based heavy oil material;

[0037] S3, dehydrating the intermediate coal-based heavy oil material and then filtering and purifying it to obtain the purified coal-based heavy oil.

[0038] In the embodiments of the present invention, by adding a diluent, a purifying agent, a viscosity reducer and a dispersant to a coal-based heavy oil raw material containing a large amount of impurities such as metals and ash, not only can the oil-soluble metals in the coal-based heavy oil raw material contact and react with the purifying agent at the oil-water interface, causing metal ions to ionize or form precipitates and chelates, thereby separating the oil-soluble metals; at the same time, the viscosity of the system can also be reduced, enabling effective dispersion of macromolecules such as resins and asphaltenes in the coal-based heavy oil raw material, making it easier to filter and separate the metals and ash in the coal-based heavy oil raw material, and not prone to clogging. This method can achieve the removal of impurities such as metals and ash in the coal-based heavy oil, effectively reduce the metal content and solid content of the coal-based heavy oil, greatly reduce the processing difficulty of the purified coal-based heavy oil, expand the application fields, and the purification method has a simple process, is easy to operate, and does not require the additional generation of a large amount of coal chemical wastewater, being environmentally friendly.

[0039] In some specific embodiments, the diluent includes at least one of naphtha, diesel oil, wash oil, benzene, xylene, toluene, tetrahydrofuran, N-methylpyrrolidone, 100# solvent oil, and 150# solvent oil. By adding the above diluent, the viscosity of the mixed system can be reduced, the fluidity can be enhanced, and it is easy to transport.

[0040] In some specific embodiments, the weight ratio of the diluent to the coal-based heavy oil raw material is 0.01:1 to 10:1, and non-limiting examples are: 0.01:1, 0.5:1, 1:1, 2:1, 4:1, 10:1, etc. If the addition amount of the diluent is too high, the actual processing amount of the coal-based heavy oil will be too low, and the economy will be poor.

[0041] In some specific embodiments, the purifying agent includes at least one of formic acid, acetic acid, citric acid, phosphoric acid, carboxylate, phosphate, ethylenediaminetetraacetic acid, and ethylenediaminetetraacetic acid derivatives. By adding the above purifying agent, the metals in the coal-based heavy oil can form chelates, facilitating subsequent separation;

[0042] And / or, the viscosity reducer includes at least one of polyoxyethylene nonylphenol ether-10, sodium dodecylbenzenesulfonate, sodium octadecanoate, sodium dodecylnonylphenol ether sulfate-10, sodium dodecylnonylphenol ether ethyl sulfonate-4, carboxymethyl dodecylnonylphenol ether-10, and α-olefin sulfonate. By adding the above viscosity reducer, the viscosity of the entire mixed system can be reduced, facilitating the transportation and filtration of the raw material, and not prone to clogging the filtration device;

[0043] And / or, the dispersant includes at least one of clay, diatomite, kaolin, polycarbonol polyether phosphate, and polycarboxylic acid higher alcohol ester. By adding the above dispersant, the heavy components and light components in the coal-based heavy oil can be kept in a stable state, not easily separated, thereby maintaining the feasibility of the operation and avoiding the occurrence of device clogging.

[0044] In some specific embodiments, the weight ratio of the purifying agent, the viscosity reducer and the dispersant is (1 to 100):(1 to 100):(1 to 100). Non-limiting examples include: 1:1:1, 1:1:5, 1:2:5, 1:10:1, 1:30:100, 5:28:70, 10:30:100, etc.

[0045] In some specific embodiments, the weight of the purifying agent is 0.01% to 1% of the weight of the coal-based heavy oil raw material. Non-limiting examples include: 0.01%, 0.05%, 0.1%, 0.5%, 0.8%, 1%; preferably 0.05% to 0.5%. Non-limiting examples include: 0.05%, 0.85%, 0.1%, 0.2%, 0.5%. If the addition amount of the purifying agent is too low, the oil-soluble metals in the coal-based heavy oil raw material cannot be completely precipitated and separated, resulting in incomplete purification; however, if the addition amount of the purifying agent is too high, the cost will increase.

[0046] In some specific embodiments, the stirring and mixing time is 30 to 90 min. Non-limiting examples include: 30 min, 45 min, 60 min, 75 min, 90 min, etc.

[0047] In some specific embodiments, the filtration and purification methods include at least one of pressure filtration, atmospheric filtration, clay filtration, sedimentation separation, and cyclone separation.

[0048] In some specific embodiments, the coal-based heavy oil raw material includes at least one of coal liquefied oil, coal tar, coal liquefaction residue, and coal-based asphalt.

[0049] The following are non-limiting examples and comparative examples of the present invention. It should be noted that: the solutions of the comparative examples are not prior art, but are only set for comparison with the solutions of the examples and do not limit the present invention. Conventional instruments and equipment in the art are used in the following examples and comparative examples. For the experimental methods without specific conditions noted in the examples and comparative examples, they are conventional methods and conventional conditions well-known in the art, or methods and conditions recommended by the manufacturer. Unless otherwise specified, all raw materials used in the following examples and comparative examples are conventional commercially available products or can be prepared by known methods.

[0050] Example 1

[0051] This example provides a method for purifying coal-based heavy oil, including the following steps:

[0052] S1, adding 50 g of tetrahydrofuran to 100 g of medium-temperature coal tar and heating and raising the temperature until the temperature reaches 80 °C;

[0053] S2, add 0.2 g of ethylenediaminetetraacetic acid, 0.2 g of polyoxyethylene nonylphenol ether-10 and 1.0 g of diatomaceous earth, and stir and mix for 30 min to form an intermediate material of coal-based heavy oil;

[0054] S3, feed the intermediate material of medium-temperature coal tar obtained in step S2 into a fractionating tower for dehydration treatment, and then perform pressure filtration with 0.1 Mpa of nitrogen to obtain purified coal tar.

[0055] The properties of the experimental raw materials of medium-temperature coal tar and the purification results in this example are shown in Table 1.

[0056] Table 1

[0057]

[0058]

[0059] Example 2

[0060] This example proposes a purification method for coal-based heavy oil, including the following steps:

[0061] S1, add 50 g of tetrahydrofuran to 100 g of medium-low temperature coal tar, and heat up until the temperature reaches 90 °C;

[0062] S2, add 0.1 g of citric acid, 0.1 g of ethylenediaminetetraacetic acid, 0.1 g of sodium octadecanoate and 0.5 g of clay, and stir and mix for 60 min to form an intermediate material of medium-low temperature coal tar;

[0063] S3, feed the intermediate material of medium-low temperature coal tar obtained in step S2 into a fractionating tower for dehydration treatment, and then perform pressure filtration with a filter press to obtain purified coal tar.

[0064] The properties of the experimental raw materials of medium-low temperature coal tar and the purification results in this example are shown in Table 2.

[0065] Table 2

[0066]

[0067] Example 3

[0068] This example proposes a purification method for coal-based heavy oil, including the following steps:

[0069] S1, add 400 g of wash oil to 100 g of coal liquefaction residue, and heat up until the temperature reaches 120 °C;

[0070] S2, add 0.01 g of phosphoric acid, 0.3 g of polyoxyethylene nonylphenol ether-10, 1.0 g of diatomaceous earth, and stir and mix for 90 min to form an intermediate material of coal liquefaction residue;

[0071] S3. Feed the intermediate of coal liquefaction residue obtained in step S2 into a fractionating column for dehydration treatment. After dehydration, use a filter press for pressure filtration to obtain the purified coal liquefaction residue.

[0072] In this example, the properties of the experimental raw materials of coal liquefaction residue and the purification results are shown in Table 3.

[0073] Table 3

[0074] Item Coal liquefaction residue Purified coal liquefaction residue <![CDATA[Density, g / cm 3 > 1.3 1.2 Water content, wt% 0.08 0.06 Ash content, % 15.4 0.1 Quinoline insoluble matter, % 22.5 0.15 Ash removal rate, wt% / 99.4

[0075] Comparative Example 1

[0076] This comparative example presents a purification method for coal-based heavy oil, including the following steps:

[0077] S1. Add 50 g of tetrahydrofuran to 100 g of medium-temperature coal tar and heat it up until the temperature reaches 80 °C.

[0078] S2. Then add 0.2 g of polyoxyethylene nonylphenol ether-10 and 1.0 g of diatomaceous earth, and stir and mix for 30 min to form an intermediate of coal-based heavy oil.

[0079] S3. Feed the intermediate of medium-temperature coal tar obtained in step S2 into a fractionating column for dehydration treatment. After dehydration, use 0.1 Mpa nitrogen for pressure filtration to obtain the purified coal tar.

[0080] In this comparative example, the properties of the experimental raw materials of medium-temperature coal tar and the purification results are shown in Table 4.

[0081] Table 4

[0082]

[0083] Comparative Example 2

[0084] This comparative example presents a purification method for coal-based heavy oil, including the following steps:

[0085] S1. Add 50 g of tetrahydrofuran to 100 g of medium-low temperature coal tar and heat it up until the temperature reaches 90 °C.

[0086] S2. Then add 0.2 g of decalcifying agent (nitric acid), 0.1 g of sodium octadecanoate and 0.5 g of clay, and stir and mix for 60 min to form an intermediate of medium-low temperature coal tar.

[0087] S3. Feed the intermediate of medium-low temperature coal tar obtained in step S2 into a fractionating column for dehydration treatment. After dehydration, use a filter press for pressure filtration to obtain the purified coal tar.

[0088] The properties of the experimental raw materials of low-temperature coal tar in this comparative example and the purification results are shown in Table 5.

[0089] Table 5

[0090]

[0091] Comparative Example 3

[0092] This comparative example proposes a purification method for coal-based heavy oil, including the following steps:

[0093] S1, Add 400 g of wash oil to 100 g of coal liquefaction residue, and heat it up until the temperature reaches 120 °C;

[0094] S2, Then add 0.01 g of phosphoric acid and stir and mix for 90 min to form an intermediate material of coal liquefaction residue;

[0095] S3, Feed the intermediate material of coal liquefaction residue obtained in step S2 into a fractionating tower for dehydration treatment, and then use a filter press for pressure filtration to obtain the purified coal liquefaction residue.

[0096] The properties of the experimental raw materials of coal liquefaction residue in this comparative example and the purification results are shown in Table 6.

[0097] Table 6

[0098]

[0099] By comparing the examples and comparative examples, it can be found that compared with Comparative Examples 1-3, Examples 1-3 of the present invention by using the combined technology of diluent, purifying agent, viscosity reducer and dispersant, are beneficial to the formation of precipitates and chelates of fine particles in coal-based heavy oil and then removal, with a high inorganic mineral removal rate and a low ash content of the product after solid-liquid separation. In the field of hydrorefining, it can greatly reduce the blockage of hydroprocessing equipment, pipelines and catalyst beds, and achieve long-term stable operation of full-range hydroprocessing; in the field of carbon material processing, this ultra-low ash purification material is a high-quality raw material for manufacturing high-performance carbon fibers, needle coke, lithium battery anode materials and other high-end carbon materials, broadening the source of low-cost raw materials for carbon material preparation and having a wide application prospect.

[0100] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0101] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for purifying coal-based heavy oil, characterized in that: The steps include: S1, adding a diluent to the coal-based heavy oil raw material and heating it until the temperature reaches 60-200°C; S2, adding a purifier, a viscosity reducer and a dispersant, stirring and mixing to form a coal-based heavy oil intermediate material; S3, filtering and purifying the coal-based heavy oil intermediate material after dehydration to obtain purified coal-based heavy oil.

2. The method for purifying coal-based heavy oil according to claim 1, characterized in that: The diluent includes at least one of naphtha, diesel, wash oil, benzene, xylene, toluene, tetrahydrofuran, N-methylpyrrolidone, 100# solvent oil, and 150# solvent oil.

3. The method for purifying coal-based heavy oil according to claim 1, characterized in that: The weight ratio of the diluent to the coal-based heavy oil feedstock is 0.01:1 to 10:

1.

4. The method for purifying coal-based heavy oil according to claim 1, characterized in that: The purifier includes at least one of formic acid, acetic acid, citric acid, phosphoric acid, carboxylates, phosphates, ethylenediaminetetraacetic acid, and ethylenediaminetetraacetic acid derivatives; And / or, the viscosity reducer includes at least one of polyoxyethylene nonylphenol ether-10, sodium dodecylbenzene sulfonate, sodium octadecanoate, sodium dodecyl nonylphenol ether sulfate-10, sodium dodecyl nonylphenol ether ethyl sulfonate-4, carboxymethyl dodecyl nonylphenol ether-10, and α-olefin sulfonate; And / or, the dispersant includes at least one of white clay, diatomaceous earth, kaolin, polyol polyether phosphate, and polycarboxylic acid high alcohol ester.

5. The method for purifying coal-based heavy oil according to claim 4, characterized in that: The weight ratio of the purifier, the viscosity reducer and the dispersant is (1-100):(1-100):(1-100).

6. The method for purifying coal-based heavy oil according to claim 1, characterized in that: The weight of the purifier is 0.01% to 1% of the weight of the coal-based heavy oil raw material.

7. The method for purifying coal-based heavy oil according to claim 6, characterized in that: The weight of the purifier is 0.05% to 0.5% of the weight of the coal tar raw material.

8. The method for purifying coal-based heavy oil according to claim 1, characterized in that: The stirring and mixing time is 30 to 90 minutes.

9. The method for purifying coal-based heavy oil according to claim 1, characterized in that: The filtering and purification method includes at least one of pressure filtration, normal pressure filtration, clay filtration, sedimentation separation, and cyclone separation.

10. The method for purifying coal-based heavy oil according to claim 1, characterized in that: The coal-based heavy oil raw material includes at least one of coal liquefaction oil, coal tar, coal liquefaction residue, and coal-based asphalt.

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