Coal tar impurity removal method and system

Abstract

The invention belongs to the technical field of coal tar impurity removal, and relates to a coal tar impurity removal method and system.The method comprises the steps that water in coal tar to be treated is evenly mixed with coal tar components; heating the uniformly mixed coal tar to a first temperature to obtain heated coal tar; mixing the first group of liquid medicine with the heated coal tar at a first temperature to obtain a first liquid medicine and coal tar mixture, carrying out evaporation precipitation treatment on the first liquid medicine and coal tar mixture to obtain first purified coal tar, and mixing the second group of liquid medicine with the first purified coal tar to obtain a second liquid medicine and coal tar mixture; heating the second liquid coal tar mixture to a second temperature, reacting to obtain a coal tar mixture with ion coagulation impurities, and dehydrating to obtain a dehydrated coal tar mixture with ion coagulation impurities; and carrying out vacuum light hydrocarbon removal on the dehydrated coal tar mixture with the ion coagulation impurities, and then carrying out two-stage filtration to obtain pure coal tar without impurities. According to the technical scheme provided by the invention, impurities in the coal tar can be effectively removed.

Description

Technical Field

[0001] The present application relates to the technical field of coal tar impurity removal, and more specifically, to a method and system for removing impurities from coal tar. Background Art

[0002] Coal tar is a black or brown viscous liquid obtained by placing coal in a retort furnace and retorting it at 450 to 800°C. Its density is 0.90 to 1.20 g / cm 3 , among which the total metal content is 110-450PPm, the water content is 1%-6%, and the main components are a mixture of phenol, aromatic hydrocarbons and heterocyclic compounds. In addition, it also contains quinoline insolubles such as salt, metal, coal powder, asphalt, colloid, etc. Coal tar is further processed by hydrogenation unit for refining, cracking, fractionation, etc. to obtain diesel, naphtha, liquid hydrocarbons, dry gas, sulfur and other products, and its development and utilization value is constantly increasing.

[0003] However, during the processing, metal impurities in coal tar can poison and inactivate hydrogenation catalysts, and metals, asphalt, and colloids can rapidly increase the pressure difference of the catalyst bed and make it impossible to produce for a long period of time; quinoline insoluble substances such as asphalt and colloids in coal tar can cause serious blockages in hydrogenation reactors, heat exchangers, filters, pipelines, etc.; coal powder in coal tar can be freed into diesel, naphtha and other products, seriously affecting product quality; and water in coal tar can cause large fluctuations in the temperature of the heating furnace, which is very harmful to the safety, stability, quality, and long-term production of the hydrogenation unit. Therefore, before entering the hydrogenation unit, the water in the coal tar must be completely removed, and impurities such as metals, coal powder, asphalt, and colloids that cannot be dissolved by quinoline must be removed to ensure efficient processing and use of coal tar.

[0004] The existing method is to add dispersant, demulsifier, light oil, and then filter and back-blow through a sintered mesh precision filter. Although this method can obtain purified coal tar with good quality, it is complicated in process, difficult to operate, and costly, and has low production efficiency and pollutes the environment, making it difficult to meet the needs of large-scale continuous production. In addition, sedimentation, centrifugation, dilution, and extraction are combined, and the cost is also high and the production efficiency is low. On this basis, a method for anhydrous desalination and demetallization of coal tar has also been produced. This method uses an organic flocculant to react with salt and metal to form agglomerates, and then filter to remove impurities. Although this method can better remove salt and metal from coal tar, the subsequent hydrogenation product has good quality and high yield, it does not disperse and evenly stir the water in the oil before the coal tar enters the pretreatment system, the reaction temperature fluctuates greatly, and the impurity removal is not thorough. A hard coke layer formed by the aggregation of asphalt and colloid due to the high temperature environment is found on the upper surface of the reactor bed, which increases the resistance of the hydrogenation reactor bed. Suspended matter containing black coal powder can be clearly seen in the finished product, which seriously affects the quality of the product. Summary of the invention

[0005] The technical problem to be solved by the embodiments of the present application is that the existing coal tar impurity removal method does not remove impurities thoroughly, resulting in increased resistance of the coal tar processing equipment and affecting the quality of the processed products.

[0006] In order to solve the above technical problems, the present application provides a method for removing impurities from coal tar, which adopts the following technical solution:

[0007] Evenly mixing the water in the coal tar to be treated with the coal tar components to obtain mixed coal tar;

[0008] heating the mixed coal tar to a first temperature to obtain heated coal tar;

[0009] At the first temperature, mixing the prefabricated first group of liquid medicines with the heated coal tar to obtain a first liquid medicine-coal tar mixture;

[0010] At the first temperature, subjecting the first liquid-to-coal tar mixture to an evaporation precipitation process to obtain a first purified coal tar;

[0011] At the first temperature, mixing the pre-made second group of liquid medicine with the first purified coal tar to obtain a second liquid medicine coal tar mixture;

[0012] Heating the second liquid coal tar mixture to a second temperature to obtain a coal tar mixture with ion agglomerates and impurities;

[0013] Dehydrating the coal tar with ion agglomerate impurity mixture to obtain a dehydrated coal tar with ion agglomerate impurity mixture;

[0014] Vacuuming the dehydrated coal tar with ion agglomerate impurity mixture to remove light hydrocarbons to obtain a second purified coal tar;

[0015] The second purified coal tar is subjected to two-stage filtration to obtain pure coal tar from which impurities are removed.

[0016] Furthermore, the step of uniformly mixing the water in the coal tar to be treated with the coal tar components to obtain the mixed coal tar comprises:

[0017] In a normal pressure storage tank, the coal tar to be treated is heated to 60-85° C.;

[0018] The coal tar to be treated is stirred and dispersed by mechanical stirring or liquid flow stirring at 60-85°C.

[0019] Further, the first group of drug liquids comprises a first group of drugs and water, and the mass percentage concentration of the first group of drugs in the first group of drug liquids is 1% to 60%; wherein the first group of drugs is selected from at least one of fatty alcohol ether phosphate, polyacrylic acid, polycarboxylic acid higher alcohol ester, pyrophosphate, polymer polyol, polyether polyol, stearic acid, alkyl sulfonate, phosphate, sulfonic acid and sulfonate; and / or

[0020] The second group of drug solutions includes a second group of drugs and water, and the mass percentage concentration of the second group of drugs in the second group of drug solutions is 1% to 60%; wherein the second group of drugs is selected from at least one of polyaspartate, polycarboxylic acid and polycarboxylate, polyepoxysuccinate, polycarboxylic acid high-carbon alcohol ester, alkyl sulfonate, inorganic acid and inorganic acid salt, phosphate, and maleic acid octyl sulfonate.

[0021] Furthermore, the step of mixing the prefabricated first group of liquid medicines with the heated coal tar to obtain a first liquid medicine-coal tar mixture comprises:

[0022] respectively feeding the first group of liquid medicines and the heated coal tar at the first temperature into a first-stage static mixer;

[0023] In the first-stage static mixer, the non-ionized impurities in the heated coal tar are fully contacted and mixed with the first group of liquid medicines to obtain a first liquid medicine-coal tar mixture; and / or

[0024] The step of mixing the prefabricated second group of liquid medicines with the first purified coal tar to obtain a second liquid medicine-coal tar mixture comprises:

[0025] sending the second group of liquid medicines at the first temperature and the first purified coal tar to the second-stage static mixer respectively;

[0026] In the second-stage static mixer, the first purified coal tar and the second group of liquid medicines are fully and evenly mixed to obtain a second liquid medicine-coal tar mixture.

[0027] Furthermore, the step of heating the second liquid coal tar mixture to the second temperature to obtain a coal tar mixture with ion agglomerated impurities comprises:

[0028] The second liquid coal tar mixture is heated to the second temperature, and the ion-bearing impurities in the second liquid coal tar mixture fully react with the second group of liquid medicines at the second temperature to obtain a coal tar impurity mixture with ion agglomerates.

[0029] Furthermore, the step of dehydrating the coal tar with ion agglomerate impurity mixture to obtain a dehydrated coal tar with ion agglomerate impurity mixture comprises:

[0030] The coal tar with ion agglomerate impurity mixture is sent to a super cyclotron, and the coal tar with ion agglomerate impurity mixture generates a gravitational acceleration greater than a preset threshold value through the inner wall of the super cyclotron;

[0031] Under the action of the density difference of each component in the coal tar with ion agglomerate impurity mixture, water vapor and dehydrated stratified products are generated by the gravitational acceleration, and the dehydrated stratified products are dehydrated coal tar with ion agglomerate impurity mixture;

[0032] The water vapor is discharged from the steam outlet of the super cyclotron, and the dehydrated coal tar with ion condensate impurity mixture is discharged from the bottom of the super cyclotron.

[0033] Furthermore, the step of vacuum removing light hydrocarbons from the dehydrated coal tar with ion agglomerate impurity mixture to obtain the second purified coal tar comprises:

[0034] The dehydrated coal tar with ion agglomerate impurity mixture is input into a vacuum device, and the dehydrated coal tar with ion agglomerate impurity mixture is heated by a heat medium in the vacuum device;

[0035] During the heating process, the light hydrocarbon components in the dehydrated coal tar with ion agglomerate impurity mixture are fully evaporated and discharged from the vacuum device to obtain the precipitated second purified coal tar;

[0036] The second purified coal tar is output from the vacuum device.

[0037] Furthermore, the two-stage filtration includes a first-stage filtration and a second-stage filtration; the first-stage filtration is carried out in a centrifugal filter, used to filter out ion-agglomerated impurities of a first particle size in the second purified coal tar; the second-stage filtration is carried out in a plate and frame pressure filter, used to filter out ion-agglomerated impurities of a second particle size in the second purified coal tar; wherein the first particle size is larger than the second particle size.

[0038] Furthermore, after the step of performing two-stage filtration on the second purified coal tar, the method further comprises:

[0039] Seal devices are respectively provided on the centrifugal filter body and the plate-and-frame press body to prevent the escape of oil mist and irritating gas;

[0040] Oil mist and irritating gases are transported to the oil-gas separation device through pipelines for harmless treatment. When the treated gases meet environmental emission standards, they are discharged into the atmosphere.

[0041] In order to solve the above technical problems, an embodiment of the present application also provides a coal tar impurity removal system, which uses a coal tar impurity removal method as described above to remove coal tar impurities.

[0042] Compared with the prior art, this application has the following beneficial effects:

[0043] The coal tar impurity removal method provided in the present application disperses the water in the impurity-containing coal tar to be treated and mixes it evenly with the coal tar to avoid uneven temperature distribution caused by the evaporation of local water due to the large specific heat capacity of water in the subsequent reaction, which takes away a large amount of heat; impurities are condensed in an environment where water and coal tar are evenly mixed, and then water is removed, light hydrocarbons are removed by vacuum, and impurities with ion agglomerates are filtered. The reaction environment is stable, impurities in the coal tar can be effectively removed, damage to the coal tar processing equipment can be avoided, and the quality of the processed products can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the scheme in the present application, a brief introduction is given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 It is a flow chart of an embodiment of a method for removing impurities from coal tar according to the present application. DETAILED DESCRIPTION

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0047] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0048] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0049] The present invention provides a method for removing impurities from coal tar. Figure 1 , showing a flow chart of the coal tar impurity removal method, comprising the following steps:

[0050] Step S10, mixing the water in the coal tar to be treated with the coal tar components uniformly to obtain mixed coal tar.

[0051] The coal tar to be treated contains water and impurities, and the impurities mainly include salt, metal, coal powder, asphalt, colloid and other quinoline insolubles; the coal tar components are mainly a mixture of phenol, aromatic hydrocarbons and heterocyclic compounds.

[0052] Specifically, the coal tar to be treated is heated to 60-85° C. in a normal pressure storage tank; and the coal tar to be treated is stirred and dispersed by mechanical stirring or liquid flow stirring at 60-85° C.

[0053] The coal tar to be treated is stirred in the liquid storage tank by mechanical stirring or liquid flow stirring to break up the water accumulated in the coal tar, disperse the water and mix it evenly with the coal tar components. In the subsequent reaction process, because the water and coal tar components are fully mixed, the temperature depression will not be formed in the local position due to the large specific heat capacity of water. When the water evaporates, it will not take away a lot of heat due to the evaporation of local water, causing uneven temperature distribution. In this way, the temperature of each part of the coal tar can be adjusted, which is conducive to the condensation reaction of impurities at an ideal temperature. The liquid storage tank is a normal pressure metal tank or plastic tank.

[0054] Before the dispersive stirring, the coal tar to be treated is heated to 60-85° C. and then stirred to improve the fluidity of the coal tar, thereby enhancing the mixing effect of the coal tar components and water.

[0055] Step S20, heating the mixed coal tar to a first temperature to obtain heated coal tar.

[0056] In this embodiment, the first stage shell and tube heat exchanger can be used to heat the mixed coal tar to obtain heated coal tar, wherein the first temperature is 95°C to 110°C.

[0057] It should be understood that the temperature of heating the coal tar may be any temperature between 95°C and 110°C, for example, 95°C, 100°C, 105°C or 110°C.

[0058] Step S30, mixing the prefabricated first group of liquid medicines with heated coal tar at a first temperature to obtain a first liquid medicine-coal tar mixture.

[0059] Impurities in coal tar include non-ionic impurities and ionic impurities. The first group of liquid chemicals is used to condense non-ionic impurities, wherein non-ionic impurities mainly include coal ash, carbon particles, asphalt, colloid, mud, sand, etc.

[0060] Wherein, the first group of drug solutions is pre-prepared, the first group of drug solutions comprises the first group of drugs and water, and the mass percentage concentration of the first group of drugs in the first group of drug solutions is 1% to 60%. For example, the mass percentage concentration range can be 1-10%, 1-20%, 1-30%, 1-40%, 1-50%, 10-20%, 10-30%, 10-40%, 10-50%, 10-60%, 20-40%, 20-60%, 30-50%, 30-60%, 40-50%, 40-60% or 50-60%.

[0061] The first group of drugs is selected from at least one of fatty alcohol ether phosphate, polyacrylic acid, polycarboxylic acid higher alcohol ester, pyrophosphate, high polymer polyol, polyether polyol, stearic acid, alkyl sulfonate, phosphate, sulfonic acid and sulfonate.

[0062] The first group of drugs has the ability to disperse and demulsify asphalt and colloid, and to flocculate. They can disperse impurities such as coal ash, carbon particles, mud and sand from asphalt and colloid, and through the flocculation ability, flocculate the impurities and part of the asphalt and colloid into clumps and settle to the bottom.

[0063] The first liquid medicine-coal tar mixture is a mixture of a first group of liquid medicines and heated coal tar. Specifically, the first group of liquid medicines at a first temperature and the heated coal tar are respectively fed into a first-stage static mixer; in the first-stage static mixer, the non-ionized impurities in the heated coal tar are fully contacted and mixed with the first group of liquid medicines to obtain the first liquid medicine-coal tar mixture.

[0064] For example, a first group of chemical liquids at a first temperature are transported to a lateral inlet of a first-stage static mixer through a pipeline and fed into the first-stage static mixer, and heated coal tar heated to a first temperature is transported to an axial inlet of the first-stage static mixer through a pipeline and fed into the first-stage static mixer, so that the first group of chemical liquids and the heated coal tar are mixed in the first-stage static mixer.

[0065] In this embodiment, during the mixing process of the first group of liquid medicines and the heated coal tar, the temperature of the first group of liquid medicines is adapted to the temperature of the coal tar so that the two liquid streams of the first group of liquid medicines and the heated coal tar can be evenly mixed, so that the first group of medicines and the non-ionized impurities in the coal tar can contact and react fully and condense into non-ionized impurities.

[0066] The mass percentage concentration of the first group of drugs in the first group of drug solutions should be guaranteed to be able to fully contact with the heated coal tar. Secondly, the first group of drugs will not be thermally decomposed at the first temperature, and the reaction speed is moderate, which can ensure the effect of the mixed drugs.

[0067] It should be noted that pressurizing the first group of drug solutions with heated coal tar to 0.5-5.01 MPa before mixing can improve the mixing efficiency and allow the first group of drugs to be in more complete contact with non-ionic impurities in the coal tar.

[0068] Step S40, subjecting the first liquid medicine-coal tar mixture to an evaporation precipitation process at a first temperature to obtain a first purified coal tar.

[0069] In this embodiment, the evaporation precipitation treatment can be achieved by a flash precipitator, which is connected to the first-stage static mixer through a pipeline. At a first temperature, the first liquid medicine-coal tar mixture is transported to the interior of the flash precipitator through a pipeline, so that the non-ionized impurities in the first liquid medicine-coal tar mixture are fully contacted and reacted with the first medicine to condense into non-ionized condensate impurities. At the same time, during the reaction, water vapor and combustible gas flash and are discharged from the top of the flash precipitator, and the non-ionized condensate impurities are precipitated to the bottom of the flash precipitator and discharged regularly, thereby obtaining the first purified coal tar from which a large amount of water, combustible gas and non-ionized impurities have been removed in the side line of the flash precipitator.

[0070] The pressure inside the flash precipitator is set to -0.090 MPa to -0.080 MPa, and the temperature is set to 105 to 110 degrees Celsius. By using the sudden drop in pressure, water vapor and combustible gas flash out from the liquid and are discharged from the top. They are then transferred to the oil and gas separation device for gas-liquid separation and harmless treatment, and are discharged into the atmosphere after meeting environmental emission standards.

[0071] The volume of the flash precipitator must be sufficient to allow the "first liquid coal tar mixture" to stay for 45 to 60 minutes. A heating coil for adjusting the liquid temperature and a baffle for stagnant liquid are also provided in the middle and lower part of the flash precipitator. The side line outlet of the flash precipitator is connected to the inlet of the intermediate transfer pump. The first purified coal tar is pressurized by the intermediate transfer pump and then transferred to the axial inlet of the second-stage static mixer.

[0072] Step S50, mixing the pre-made second group of liquid medicine with the first purified coal tar at a first temperature to obtain a second liquid medicine-coal tar mixture.

[0073] The second group of liquid medicines is pre-formulated and used to condense ion-carrying impurities, and the ion-carrying impurities mainly include metal ions. The second group of liquid medicines includes the second group of drugs and water, and the mass percentage concentration of the second group of drugs in the second group of liquid medicines is 1% to 60%. For example, the mass percentage concentration range can be 1-10%, 1-20%, 1-30%, 1-40%, 1-50%, 10-20%, 10-30%, 10-40%, 10-50%, 10-60%, 20-30%, 20-40%, 20-60%, 30-50%, 30-60%, 40-50%, 40-60% or 50-60%, etc.

[0074] The second group of drugs is selected from at least one of polyaspartate, polycarboxylic acid and polycarboxylate, polyepoxysuccinate, polycarboxylic acid higher alcohol ester, alkyl sulfonate, inorganic acid and inorganic acid salt, phosphate, and maleic octyl sulfonate.

[0075] The second group of drugs has dispersing, demulsifying and chelating effects. They disperse the ionized impurities from the coal tar through the dispersing and demulsifying effects, and condense the ionized impurities into large particle agglomerates through the chelating effect.

[0076] Under the condition of the first temperature, the second group of liquid medicines is mixed with the first purified coal tar, and the specific process is: the second group of liquid medicines at the first temperature and the first purified coal tar are respectively sent to the second-stage static mixer; in the second-stage static mixer, the first purified coal tar and the second group of liquid medicines are fully mixed to obtain a second liquid medicine coal tar mixture. The second liquid medicine coal tar mixture is a mixture of the second group of liquid medicines and the first purified coal tar.

[0077] For example, the second group of liquid medicines at the first temperature is transported to the lateral inlet of the second-stage static mixer through a pipeline and sent into the second-stage static mixer. After being pressurized by an intermediate transfer pump, the first purified coal tar from the outlet of the flash precipitator is transported to the axial inlet of the second-stage static mixer through a pipeline and sent into the second-stage static mixer, so that the first purified coal tar and the second group of liquid medicines are evenly mixed.

[0078] In this embodiment, during the mixing process of the second group of liquid medicines and the first purified coal tar, the temperature of the second group of liquid medicines is adapted to the temperature of the first purified coal tar, so that the two liquid streams of the second group of liquid medicines and the first purified coal tar can be evenly mixed in the second-stage static mixer, so that the second group of drugs and the ionic impurities in the first purified coal tar can contact and react fully, and condense into ionic agglomerated impurities, and finally come out from the only outlet of the second-stage static mixer to obtain a second liquid medicine coal tar mixture.

[0079] The mass percentage concentration of the second group of drugs in the second group of drug solution should be guaranteed to be able to fully contact with the first purified coal tar. Secondly, the second group of drugs will not be thermally decomposed at the first temperature, and the reaction speed is moderate, which can ensure the effect of the mixed drugs.

[0080] In some embodiments, the second group of drug liquids is pressurized to 0.5-5.01 MPa, and then the pressurized second group of drug liquids is heated to the first temperature and then mixed with the first purified coal tar. This can improve the mixing efficiency and further allow the second group of drugs to fully contact the ionic impurities in the first purified coal tar.

[0081] Specifically, the second group of liquid medicines is pressurized by a volumetric pump, and the pressurized second group of liquid medicines is heated to a first temperature so that the second group of liquid medicines can be smoothly mixed with the first purified coal tar during the mixing process.

[0082] Step S60, heating the second liquid coal tar mixture to a second temperature to obtain a coal tar impurity mixture with ion agglomerates by reaction.

[0083] In this embodiment, the second temperature is 135-165° C. Through the second heating, the temperature of the second liquid coal tar mixture and the second group of liquid medicines reaches an environment that is conducive to the reaction of ionized impurities with the second group of drugs. Under the condition of the second temperature, the ionized impurities in the second liquid coal tar mixture react fully with the second group of liquid medicines, that is, the second group of drugs condense the ionized impurities to obtain a coal tar ionized agglomerated impurity mixture.

[0084] In this embodiment, a second-stage shell and tube heater is used to heat the second liquid medicine coal tar mixture by heat exchange, and the pressure of the second liquid medicine coal tar under the shell and tube heat exchange environment is 1 to 1.6 MPa. When the temperature reaches the second temperature, the flow rate of the heat flow medium is controlled by the temperature controller to control the temperature of the second liquid medicine coal tar mixture to always operate within the second temperature range of 135 to 165°C. At this temperature, the drug activity of the liquid medicine and the dispersibility and permeability of the coal tar are good, and the coal tar will not undergo polymerization and coking reaction due to high temperature, so that the ion impurities in the coal tar can fully react with the second group of drugs in the best state, and the ion agglomerated impurities generated after the reaction are not easy to decompose.

[0085] The present application improves the efficiency of injection and reaction by performing two injections and two heatings, the efficiency of impurity condensation is higher, and impurities in coal tar can be removed more effectively.

[0086] Step S70, dehydrating the coal tar with ion agglomerates and impurities mixture to obtain a dehydrated coal tar with ion agglomerates and impurities mixture.

[0087] In step S40, a large amount of water in the coal tar has been removed, but it has not been completely removed. In this embodiment, the coal tar with ion condensation impurity mixture is sent to the super cyclotron, and the coal tar with ion condensation impurity mixture generates a gravitational acceleration greater than a preset threshold through the inner wall of the super cyclotron; under the action of the density difference of each component in the coal tar with ion condensation impurity mixture, water vapor and dehydrated stratified products are generated through gravitational acceleration, and the dehydrated stratified products are dehydrated coal tar with ion condensation impurity mixture; the water vapor is discharged from the steam outlet of the super cyclotron, and the dehydrated coal tar with ion condensation impurity mixture is discharged from the bottom of the super cyclotron.

[0088] The coal tar with ion agglomerate impurity mixture is further dehydrated by a super cyclotron. For example, the coal tar with ion agglomerate impurity mixture is transported to the side line inlet of the super cyclotron through a pipeline and sent into the interior of the super cyclotron. The coal tar with ion agglomerate impurity mixture generates a super cyclotron with a gravitational acceleration greater than 500g (preset threshold) in the super cyclotron. Due to the density difference between water vapor and coal tar components, under the action of super cyclotron and density difference, water vapor is squeezed to the center of the cyclotron and discharged from the top (steam exhaust port), and the dehydrated coal tar with ion agglomerate impurity mixture is discharged from the bottom of the super cyclotron, thereby achieving oil-water separation.

[0089] Step S80, vacuum-removing light hydrocarbons from the dehydrated coal tar with ion agglomerate impurity mixture to obtain a second purified coal tar.

[0090] Specifically, the dehydrated coal tar with ion agglomerate impurity mixture is input into a vacuum device, and the dehydrated coal tar with ion agglomerate impurity mixture is heated by the heat medium in the vacuum device; during the heating process, the light hydrocarbon components in the dehydrated coal tar with ion agglomerate impurity mixture are fully evaporated and discharged from the vacuum device to obtain the precipitated second purified coal tar; the second purified coal tar is output from the vacuum device.

[0091] The vacuum device may be a vacuum tower or a vacuum tank. The dehydrated coal tar with ion agglomerate impurities mixture is transported to the vacuum device through the pipeline between the super cyclotron and the vacuum device; the light hydrocarbon components in the dehydrated coal tar with ion agglomerate impurities mixture are evaporated and discharged out of the vacuum device by heating with a heat medium, and part of the ion agglomerate impurities are precipitated at the bottom of the vacuum device; the coal tar with ion agglomerate impurities after the light hydrocarbons are removed are output at the bottom of the vacuum device, which is the second purified coal tar.

[0092] In this embodiment, heating is performed so that the light hydrocarbon components can be evaporated as much as possible from the dehydrated coal tar with ion agglomerate impurity mixture under vacuum and discharged out of the vacuum device. This ensures that when the coal tar solid impurities are subsequently filtered, there will be no fire or explosion accidents due to the light hydrocarbon combustible gas contained in the coal tar escaping to the outside of the filter body.

[0093] In some embodiments, the vacuum device maintains the temperature of the dehydrated coal tar with ion agglomerated impurities mixture at 90-135°C under a pressure of -0.0915 to -0.0036 MPa, and evaporates the light components and precipitates some of the ion agglomerated impurities in this temperature range.

[0094] The vacuum device can be a plurality of vacuum towers or vacuum tanks arranged in series, which can ensure the complete evaporation of the light hydrocarbon components.

[0095] Step S90, performing two-stage filtration on the second purified coal tar to obtain pure coal tar with impurities removed.

[0096] In this embodiment, the two-stage filtering includes a first-stage filtering and a second-stage filtering, the first-stage filtering is primary filtering, and the second-stage filtering is higher-precision filtering.

[0097] The first stage of filtration is carried out in a centrifugal filter, which is used to filter out ion-agglomerated impurities of a first particle size in the second purified coal tar; the second stage of filtration is carried out in a plate and frame pressure filter, which is used to filter out ion-agglomerated impurities of a second particle size in the second purified coal tar; wherein the first particle size is larger than the second particle size.

[0098] Specifically, the second purified coal tar is transferred to the centrifugal filter through a pipeline between the vacuum device and the centrifugal filter, and the impurities with ion agglomerates with relatively large particle sizes in the second purified coal tar are filtered out to obtain first-stage filtered coal tar; the first-stage filtered coal tar is output from the outlet of the centrifugal filter, transferred to an intermediate buffer tank through a pipeline and retained for about 10 to 15 minutes, and then pressurized to 0.01 to 1.5 MPa by a pump, and then transferred to the inlet of a plate and frame pressure filter; impurities with ion agglomerates with smaller particle sizes are filtered out by the plate and frame pressure filter, and pure coal tar free of impurities is output.

[0099] It should be understood that the filter particle size can be selected according to actual needs.

[0100] In some embodiments, sealing devices that can prevent the escape of oil mist and irritating gases are respectively provided on the centrifugal filter body and the plate and frame pressure filter body, and the oil mist and irritating gases are transported to the oil-gas separation device through pipelines for harmless treatment. The treated gas is discharged into the atmosphere when it meets environmental emission standards.

[0101] Specifically, a first sealed box is arranged in the centrifugal filter body, and a pipeline leading to a vacuum system (vacuum device and flash precipitator) is connected to one side of the first sealed box; a second sealed box is arranged in the plate and frame pressure filter body, and a pipeline leading to a vacuum system (vacuum device and flash precipitator) is connected to one side of the second sealed box; the oil mist and irritating gas collected in the first sealed box and the second sealed box is transported to the oil-gas separation device through the pipeline for harmless treatment such as cooling, separation, and adsorption to avoid air pollution.

[0102] The coal tar impurity removal method provided in the present application disperses the water in the impurity-containing coal tar to be treated and mixes it evenly with the coal tar to avoid uneven temperature distribution caused by the evaporation of local water due to the large specific heat capacity of water in the subsequent reaction; impurities are condensed in an environment where water and coal tar are evenly mixed, and then the water is removed, impurities with ion agglomerates are filtered, and toxic and harmful gases are treated. The reaction environment of the entire impurity removal process is stable and efficient, and impurities in coal tar can be effectively removed, and subsequent damage to coal tar processing equipment can be avoided, the quality of processed products can be improved, and environmental protection requirements can be met at the same time.

[0103] Based on the above-mentioned coal tar impurity removal method, the present application also provides a coal tar impurity removal system, which includes a normal pressure storage tank connected by a pipeline, a first-stage shell and tube heater, a first-stage static mixer, a flash precipitator, a second-stage static mixer, a second-stage shell and tube heater, a super gyro tube, a light hydrocarbon removal device, a centrifugal filter and a plate and frame pressure filter. The system uses a coal tar impurity removal method as described above to remove coal tar impurities.

[0104] In some embodiments, the coal tar impurity removal system further includes a first sealed box disposed in the centrifugal filter body, a second sealed box disposed in the pressure filter body, and an oil-gas separation device.

[0105] The coal tar impurity removal system provided in the present application can effectively remove impurities in coal tar, avoid subsequent damage to coal tar processing equipment, improve the quality of processed products, and meet environmental protection requirements.

[0106] Obviously, the embodiments described above are only some embodiments of the present application, rather than all embodiments. The preferred embodiments of the present application are given in the accompanying drawings, but they do not limit the patent scope of the present application. The present application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive. Although the present application is described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions recorded in the aforementioned specific implementation methods, or to perform equivalent replacement of some of the technical features therein. Any equivalent structure made using the contents of the specification and drawings of this application, directly or indirectly used in other related technical fields, is similarly within the scope of patent protection of this application.

Claims

1. A method for removing impurities from coal tar, characterized in that: The following steps are involved: Evenly mixing the water in the coal tar to be treated with the coal tar components to obtain mixed coal tar; heating the mixed coal tar to a first temperature to obtain heated coal tar; At the first temperature, mixing the prefabricated first group of liquid medicines with the heated coal tar to obtain a first liquid medicine-coal tar mixture; At the first temperature, subjecting the first liquid-to-coal tar mixture to an evaporation precipitation process to obtain a first purified coal tar; At the first temperature, mixing the pre-made second group of liquid medicine with the first purified coal tar to obtain a second liquid medicine coal tar mixture; Heating the second liquid coal tar mixture to a second temperature to obtain a coal tar mixture with ion agglomerates and impurities; Dehydrating the coal tar with ion agglomerate impurity mixture to obtain a dehydrated coal tar with ion agglomerate impurity mixture; Vacuuming the dehydrated coal tar with ion agglomerate impurity mixture to remove light hydrocarbons to obtain a second purified coal tar; The second purified coal tar is subjected to two-stage filtration to obtain pure coal tar from which impurities are removed.

2. The method for removing impurities from coal tar according to claim 1, characterized in that: The step of uniformly mixing the water in the coal tar to be treated with the coal tar components to obtain the mixed coal tar comprises: In a normal pressure storage tank, the coal tar to be treated is heated to 60-85° C.; The coal tar to be treated is stirred and dispersed by mechanical stirring or liquid flow stirring at 60-85°C.

3. The method for removing impurities from coal tar according to claim 1, characterized in that: The first group of drug solutions comprises a first group of drugs and water, wherein the mass percentage concentration of the first group of drugs in the first group of drug solutions is 1% to 60%; wherein the first group of drugs is selected from at least one of fatty alcohol ether phosphate, polyacrylic acid, polycarboxylic acid higher alcohol ester, pyrophosphate, polymer polyol, polyether polyol, stearic acid, alkyl sulfonate, phosphate, sulfonic acid and sulfonate; and / or The second group of drug solutions includes a second group of drugs and water, and the mass percentage concentration of the second group of drugs in the second group of drug solutions is 1% to 60%; wherein the second group of drugs is selected from at least one of polyaspartate, polycarboxylic acid and polycarboxylate, polyepoxysuccinate, polycarboxylic acid high-carbon alcohol ester, alkyl sulfonate, inorganic acid and inorganic acid salt, phosphate, and maleic acid octyl sulfonate.

4. The method for removing impurities from coal tar according to claim 1, characterized in that: The step of mixing the prefabricated first group of liquid medicines with the heated coal tar to obtain a first liquid medicine-coal tar mixture comprises: respectively feeding the first group of liquid medicines and the heated coal tar at the first temperature into a first-stage static mixer; In the first-stage static mixer, the non-ionized impurities in the heated coal tar are fully contacted and mixed with the first group of liquid medicines to obtain a first liquid medicine-coal tar mixture; and / or The step of mixing the prefabricated second group of liquid medicines with the first purified coal tar to obtain a second liquid medicine-coal tar mixture comprises: sending the second group of liquid medicines at the first temperature and the first purified coal tar to the second-stage static mixer respectively; In the second-stage static mixer, the first purified coal tar and the second group of liquid medicines are fully and evenly mixed to obtain a second liquid medicine-coal tar mixture.

5. The method for removing impurities from coal tar according to claim 1, characterized in that: The step of heating the second liquid coal tar mixture to the second temperature to obtain a coal tar mixture with ion agglomerated impurities comprises: The second liquid coal tar mixture is heated to the second temperature, and the ion-bearing impurities in the second liquid coal tar mixture fully react with the second group of liquid medicines at the second temperature to obtain a coal tar impurity mixture with ion agglomerates.

6. The method for removing impurities from coal tar according to claim 1, characterized in that: The step of dehydrating the coal tar with ion agglomerate impurity mixture to obtain a dehydrated coal tar with ion agglomerate impurity mixture comprises: The coal tar with ion agglomerate impurity mixture is sent to a super cyclotron, and the coal tar with ion agglomerate impurity mixture generates a gravitational acceleration greater than a preset threshold value through the inner wall of the super cyclotron; Under the action of the density difference of each component in the coal tar with ion agglomerate impurity mixture, water vapor and dehydrated stratified products are generated by the gravitational acceleration, and the dehydrated stratified products are dehydrated coal tar with ion agglomerate impurity mixture; The water vapor is discharged from the steam outlet of the super cyclotron, and the dehydrated coal tar with ion condensate impurity mixture is discharged from the bottom of the super cyclotron.

7. The method for removing impurities from coal tar according to claim 1, characterized in that: The step of vacuum removing light hydrocarbons from the dehydrated coal tar with ion agglomerate impurity mixture to obtain the second purified coal tar comprises: The dehydrated coal tar with ion agglomerate impurity mixture is input into a vacuum device, and the dehydrated coal tar with ion agglomerate impurity mixture is heated by a heat medium in the vacuum device; During the heating process, the light hydrocarbon components in the dehydrated coal tar with ion agglomerate impurity mixture are fully evaporated and discharged from the vacuum device to obtain the precipitated second purified coal tar; The second purified coal tar is output from the vacuum device.

8. The method for removing impurities from coal tar according to claim 1, characterized in that: The two-stage filtration includes a first-stage filtration and a second-stage filtration; the first-stage filtration is performed in a centrifugal filter to filter out ion-agglomerated impurities of a first particle size in the second purified coal tar; the second-stage filtration is performed in a plate and frame pressure filter to filter out ion-agglomerated impurities of a second particle size in the second purified coal tar; wherein the first particle size is larger than the second particle size.

9. The method for removing impurities from coal tar according to claim 8, characterized in that: After the step of performing two-stage filtration on the second purified coal tar, the method further comprises: Seal devices are respectively provided on the centrifugal filter body and the plate-and-frame press body to prevent the escape of oil mist and irritating gas; Oil mist and irritating gases are transported to the oil-gas separation device through pipelines for harmless treatment. When the treated gases meet environmental emission standards, they are discharged into the atmosphere.

10. A coal tar impurity removal system, characterized in that: The coal tar impurity removal system uses a coal tar impurity removal method as described in any one of claims 1 to 9 to remove coal tar impurities.

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