Multi-element extractant and its application and method for extracting lignite resin and lignite wax from lignite

Abstract

The present invention relates to the field of lignite wax preparation and discloses a multi-component extractant, its application, and a method for extracting lignite resin and lignite wax from lignite. The multi-component extractant is extractant I containing a first base solvent, additive A, and additive B, or extractant II containing a second base solvent, water, additive A, additive B, and additive C. Using the multi-component extractant of the present invention to extract lignite resin and lignite wax from lignite can reduce the amount of organic extractant used and improve the extraction efficiency of lignite resin and lignite wax from lignite with different water contents, especially higher water contents, thereby obtaining high-quality resin and lignite wax.

Description

Technical Field

[0001] The invention relates to the field of lignite wax preparation, and in particular to a multi-component extractant and application thereof, and a method for extracting lignite resin and lignite wax from lignite by using the multi-component extractant. Background Art

[0002] Lignite wax is a mineral wax extracted from wax-rich lignite using organic solvents. The two-phase model of coal posits that the "host" phase of coal is a three-dimensional, cross-linked macromolecular network, while the "guest" phase consists of small molecules embedded within this macromolecular network through non-covalent bonds. Non-covalent bonds in low-rank coals are primarily hydrogen bonds and ionic crosslinks. The solvent extraction process for lignite wax can be described as follows: the extractant penetrates and diffuses into the pores of the coal, dissolving the wax. Simultaneously, the extractant disrupts the van der Waals forces and weak complexing forces between coal molecules, releasing the wax. The underlying principle is that like dissolves like. Traditional extractant selection typically prioritizes organic solvents with high wax solubility. However, this typically imposes a water content requirement on the raw coal, with a moisture content of 10-15% being the optimal value. This is because water is insoluble in organic solvents, which hinders wax extraction. Furthermore, traditional extractants fail to effectively remove resin, resulting in a high resin content in the lignite wax and low yield and quality of the lignite resin byproduct.

[0003] Although there are many patents in the prior art that study how to improve the extraction efficiency of lignite wax, most of these patents focus on how to increase the solubility of lignite wax in the extractant and often ignore the yield and quality of the by-product lignite resin.

[0004] CN201310640304.X discloses a high-efficiency solvent composition and method for extracting lignite wax. The extraction solvent composition comprises a mixed extractant and a surfactant, comprising an ester mixed with one or more of an aromatic hydrocarbon, a cycloalkane, or a linear hydrocarbon solvent. The surfactant is a lipophilic fluorinated surfactant that reduces the viscosity and surface tension of the mixed extractant, enhancing its permeability and diffusion rate within lignite particles while also creating a directional adsorption between the coal and the wax. In principle, this patent further increases the solubility of the wax in the solvent. However, the extract in this patent has a high resin content, and the amount of the extraction solvent composition used is relatively large.

[0005] CN200810233651.X discloses a solvent and method for extracting montan wax. The extraction solvent is prepared from 1,2-dichloroethane:alcohol in a ratio of 3:7 to 10:0. Under the same production conditions, the montan wax yield is increased by 2 to 3 percentage points compared to the benzene extraction method, while the solvent cost is reduced by 10 to 20%. However, this patent also results in a high resin content in the extract and requires a large amount of extraction solvent. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problems existing in the prior art, such as low extraction efficiency of lignite wax in lignite with high water content, high resin content in lignite wax, and large amount of organic extractant required, and to provide a multi-component extractant and a method and application of extracting lignite resin and lignite wax from lignite using the multi-component extractant.

[0007] In order to achieve the above-mentioned object of the invention, the first aspect of the present invention provides a multi-component extractant, characterized in that the multi-component extractant is an extractant I containing a first base solvent, an additive A and an additive B; or,

[0008] The multi-element extractant is an extractant II containing a second basic solvent, water, additive A, additive B and additive C.

[0009] A second aspect of the present invention provides a use of the above-mentioned multi-element extractant in extracting lignite wax and lignite resin from lignite.

[0010] A third aspect of the present invention provides a method for extracting lignite wax and lignite resin from lignite, characterized in that the method comprises:

[0011] (1) contacting lignite particles with a first extractant to perform a first extraction, and then performing a first solid-liquid separation to obtain a first liquid phase and a first solid phase;

[0012] (2) subjecting the first liquid phase to a first steaming treatment to obtain first extractant vapor and lignite resin;

[0013] (3) mixing the first solid phase with a second extractant to perform a second extraction, and then performing a second solid-liquid separation to obtain a second liquid phase and a second solid phase;

[0014] (4) subjecting the second liquid phase to a second steaming treatment to obtain second extractant vapor and montan wax;

[0015] The first extractant is extractant I containing a first base solvent, additive A and additive B, and the second extractant is extractant I containing a first base solvent, additive A and additive B or extractant II containing a second base solvent, water, additive A, additive B and additive C.

[0016] Through the above-mentioned technology, the multi-component extractant provided by the present invention adds additives A, B, and / or C to the lignite wax base extractant, thereby increasing the extraction efficiency of lignite wax by more than 30%, further improving the production efficiency of lignite wax, reducing the amount of organic extractant (i.e., multi-component extractant), and more efficiently utilizing wax-rich resources. It is particularly suitable for processing lignite with a high water content. Specifically:

[0017] (1) The multi-element extractant provided by the present invention can extract lignite resin and lignite wax from lignite separately by adjusting the extraction temperature, and has a high extraction efficiency;

[0018] (2) The multi-element extractant provided by the present invention contains additives A and B, which can facilitate the formation of hydrogen bonds with the network skeleton macromolecules in the lignite, thereby increasing the effective pore size for wax extraction and achieving higher extraction efficiency;

[0019] (3) In some embodiments, the additive C is added to the multi-component extractant. When the multi-component extractant is used to extract lignite wax from lignite particles, the solubility of the lignite wax in the multi-component extractant can be greatly increased, thereby reducing the amount of the multi-component extractant used, reducing production costs, and improving environmental benefits. The additive C is particularly suitable for processing lignite with a high water content (above 25 wt%).

[0020] (4) The multi-element extractant provided by the present invention has increased adaptability to the water content of lignite, so that lignite can be directly used for extraction without drying;

[0021] (5) The multi-element extractant provided by the present invention is used to extract lignite wax and lignite resin from lignite, thereby obtaining a high-purity lignite resin product and a lignite wax with a low resin content. DETAILED DESCRIPTION

[0022] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0023] A first aspect of the present invention provides a multi-component extractant, wherein the multi-component extractant is an extractant I comprising a first base solvent, an additive A and an additive B; or

[0024] The multi-element extractant is an extractant II containing a second basic solvent, water, additive A, additive B and additive C.

[0025] In the present invention, Additive C in Extractant II can form an emulsion with water, the extract, and the base solvent, increasing the solubility of montan wax in the multi-component extractant, thereby reducing the amount of the multi-component extractant used. When Extractant II contains only the second base solvent, water, Additive A, and Additive B, the extraction efficiency of Extractant II is low. When Extractant II contains only the second base solvent, Additive A, Additive B, and Additive C, the overall organic solvent content in the extractant is high, and the extraction efficiency is low.

[0026] In some embodiments of the present invention, based on the total amount of the extractant I, the content of the first base solvent in the extractant I is 50-95 wt %, the content of the additive A is 1-30 wt %, and the content of the additive B is 1-30 wt %;

[0027] And / or, based on the total amount of the extractant II, the content of the second base solvent in the extractant II is 30-67 wt %, the content of water is 30-60 wt %, the content of the additive A is 1-20 wt %, the content of the additive B is 1-18 wt %, and the content of the additive C is 0.005-0.15 wt %.

[0028] In some embodiments of the present invention, the content of the first base solvent in the extractant I is 50-90 wt %, the content of the additive A is 5-30 wt %, and the content of the additive B is 5-25 wt %.

[0029] In some embodiments of the present invention, the content of the second base solvent in the extractant II is 30-54 wt%, the content of water is 30-60 wt%, the content of the additive A is 3-18 wt%, the content of the additive B is 3-18 wt%, and the content of the additive C is 0.005-0.105 wt%.

[0030] In some embodiments of the present invention, in order to further improve the extraction efficiency of lignite resin and lignite wax, the additive A is selected from at least one of acetic acid, propionic acid, butyric acid, and ethylenediamine.

[0031] In some embodiments of the present invention, in order to further improve the extraction efficiency of lignite resin and lignite wax, the additive B is selected from at least one of pyridine, tetrahydrofuran, cyclohexanone, and N-methyl-2-pyrrolidone.

[0032] In some embodiments of the present invention, in order to further improve the extraction efficiency of montan wax, the additive C is selected from at least one of ethyl laurate, sorbitol polyether tristearate, and dodecyldimethylaminoethyl lactone.

[0033] In some embodiments of the present invention, the first base solvent and the second base solvent are each selected from at least one of a benzene compound, an ester compound, and a hydrocarbon compound. Preferably, the ester compound is an ester compound having less than 12 carbon atoms, the benzene compound is at least one of benzene, toluene, and xylene, and the hydrocarbon compound is an alkane compound having less than 16 carbon atoms. To further improve the extraction efficiency of lignite resin and montan wax, the ester compound is ethyl acetate and / or propyl acetate, the benzene compound is toluene, and the hydrocarbon compound is preferably cyclohexane and / or n-heptane.

[0034] The inventors have found that when the multi-extractant contains the base solvent, additive A, and additive B, the base solvent, additive A, and additive B have a synergistic effect, and have high extraction efficiency for lignite resin and lignite wax in lignite at different extraction temperatures; when the multi-extractant contains the base solvent, additive A, additive B, additive C, and water, the base solvent, additive A, additive B, additive C, and water have a synergistic effect, which can further improve the extraction efficiency of lignite with a high water content, especially lignite wax with a water content of more than 25wt%.

[0035] A second aspect of the present invention provides a use of the above-mentioned multi-element extractant in extracting lignite wax and lignite resin from lignite.

[0036] A third aspect of the present invention provides a method for extracting lignite wax and lignite resin from lignite, the method comprising:

[0037] (1) contacting lignite particles with a first extractant to perform a first extraction, and then performing a first solid-liquid separation to obtain a first liquid phase and a first solid phase;

[0038] (2) subjecting the first liquid phase to a first steaming treatment to obtain first extractant vapor and lignite resin;

[0039] (3) mixing the first solid phase with a second extractant to perform a second extraction, and then performing a second solid-liquid separation to obtain a second liquid phase and a second solid phase;

[0040] (4) subjecting the second liquid phase to a second steaming treatment to obtain second extractant vapor and montan wax;

[0041] The first extractant is extractant I containing a first base solvent, additive A and additive B, and the second extractant is extractant I containing a first base solvent, additive A and additive B or extractant II containing a second base solvent, water, additive A, additive B and additive C.

[0042] In the above method provided by the present invention, the extractant I and the extractant II respectively correspond to the extractant I and the extractant II in the aforementioned multi-element extractant, and are not described in detail here.

[0043] In the present invention, the lignite particles can be obtained using conventional techniques in the art, such as crushing and screening the raw coal. The extractants I and II, as well as the method for extracting lignite wax and lignite resin from lignite, are highly adaptable to the moisture content of the lignite. Therefore, the lignite particles do not need to be dried.

[0044] In some embodiments of the present invention, the moisture content of the lignite particles is 10-50 wt %. In some embodiments of the present invention, in order to further improve the extraction rate of lignite wax, the particle size of the lignite particles is 1-10 mm.

[0045] In the present invention, the first solid-liquid separation is not particularly limited, as long as the first solid phase and the first liquid phase can be separated.

[0046] In the present invention, the second solid-liquid separation is not particularly limited, as long as the second solid phase and the second liquid phase can be separated.

[0047] In the present invention, the first solid-liquid separation and the second solid-liquid separation can be conventional solid-liquid separation operations in the art, such as filtration or hydrocyclone separation. Preferably, the solid-liquid separation is performed by hydrocyclone separation first and then by filtration.

[0048] In the present invention, the first steaming treatment and the second steaming treatment are both conventional operations in the art and are not particularly limited in the present invention. Preferably, the first steaming treatment and the second steaming treatment are rotary steaming.

[0049] In the present invention, step (1) performs a first extraction by contacting the lignite particles with a first extractant, thereby extracting the lignite resin in the lignite particles into the first extractant. Then, through solid-liquid separation, a mixture of the lignite resin and the first extractant, i.e., a first liquid phase, and lignite particles from which the lignite resin has been substantially removed, i.e., a first solid phase, can be obtained.

[0050] In some embodiments of the present invention, the mass ratio of the first extractant to the lignite particles is (2-3):1, the temperature of the first extraction is 15-35° C., and the time of the first extraction is 4-12 hours.

[0051] In the present invention, step (3) is performed by mixing the lignite particles (i.e., the first solid phase) from which the lignite resin has been substantially removed with a second extractant to perform a second extraction, thereby extracting the lignite wax from the lignite particles into the second extractant. In this case, the second extractant containing the lignite wax is a wax-rich liquid. After the second extraction is completed, solid-liquid separation is performed to obtain a mixture of the lignite wax and the second extractant, i.e., the second liquid phase, and lignite from which the lignite resin and the lignite wax have been substantially removed, i.e., the second solid phase. In some embodiments of the present invention, after desolventizing the second solid phase, defatted and dewaxed coal can be obtained.

[0052] In the present invention, the desolvation is a conventional operation in the art, for example, evaporative desolvation, i.e., removing the solvent by evaporation, which is not particularly limited in the present invention. Preferably, the evaporative desolvation can be performed using an evaporator to remove the solvent from the second solid phase in order to evaporate the solvent at a temperature higher than the boiling point of the solvent.

[0053] In some embodiments of the present invention, the volume ratio of the second extractant to the first solid phase is (2-4):1.

[0054] In the present invention, the volume of the first solid phase refers to the bulk volume of the first solid phase, that is, the first solid phase (lignite particles from which lignite resin has been substantially removed) is poured into a straight graduated cylinder, and the cylinder is gently tapped 5-6 times. The reading corresponding to the upper plane is the volume of the first solid phase.

[0055] In some embodiments of the present invention, in order to extract montan wax, the second extraction needs to be performed at a higher temperature. Preferably, in order to improve the extraction efficiency of montan wax, the second extraction temperature is 70-90°C and the second extraction time is 0.5-4 hours, preferably 0.5-2 hours.

[0056] In some embodiments of the present invention, in order to increase the solubility of the montan wax in the second extractant, the mixing in step (3) is further mixing the second extractant with the second solid phase by a circulating spraying method. The circulating spraying method is conventional in the art and will not be described in detail here.

[0057] In some embodiments of the present invention, in order to increase the solubility of montan wax in the second extractant, step (3) further includes stirring the wax-rich liquid (the second extractant containing montan wax) at a stirring speed of 3000-5000 r / min. In some embodiments of the present invention, the method further includes recovering the first extractant vapor and the second extractant vapor, respectively, and returning them to step (1) and step (3), respectively.

[0058] In some embodiments of the present invention, the recovery includes: collecting the first extractant vapor and the second extractant vapor by condensation, respectively, detecting the proportion of each component in the condensed and collected solvent, replenishing each component to the initial value according to the initial proportion, and returning to step (1) and step (3), respectively.

[0059] The present invention will be described in detail below by way of examples. Unless otherwise specified, the raw materials and reagents used in the following examples and comparative examples can all be obtained from commercial sources.

[0060] Unless otherwise specified, the methods used in the following examples are commonly used methods in the art.

[0061] The volume of the first solid phase is measured by pouring the first solid phase (lignite particles substantially free of lignite resin) into a straight graduated cylinder, gently tapping the cylinder 5-6 times, and the reading corresponding to the upper plane is the volume of the first solid phase.

[0062] Since the content of lignite wax varies in different regions, the extraction efficiency used in the examples and comparative examples reflects the extraction effect of lignite wax and lignite resin. The extraction efficiency of lignite wax is defined as: (the mass of lignite wax extracted using the extractant / the mass of the extract extracted using toluene)*100%; the extraction efficiency of lignite resin is defined as: (the mass of lignite resin extracted using the extractant / the mass of the extract extracted using toluene)*100%. Among them, extraction with toluene means using toluene to extract the lignite particles under the same conditions in each embodiment. Specifically, the method of extraction with toluene is: using toluene as the extractant, with a mass ratio of extractant to lignite particles = 3:1, adding the extractant to the lignite particles in a circulating spraying manner at 80°C, extracting the lignite particles for 2 hours, then filtering, and rotary evaporating to obtain a mixture of lignite wax and resin.

[0063] The resin and asphalt content are determined in accordance with the national standard "GB / T 2559-2005 Montan Wax Determination Method".

[0064] Preparation of lignite granules: Lignite was purchased from Baoqing Coal and Electrochemical Co., Ltd. After crushing and screening, lignite granules with a particle size of 1-3 mm were selected. The moisture content of the lignite granules was 48 wt%. The lignite granules were divided into several portions and dried in a 40°C forced air drying oven to different moisture contents (by weight). The resulting lignite granules with different moisture contents were used in the following experiments.

[0065] Example 1

[0066] (1) The first extractant is prepared according to a mass ratio of the first base solvent (ethyl acetate): additive A (acetic acid): additive B (tetrahydrofuran) = 76:14:10. 500 g of lignite particles having a water content of 48 wt% are taken and subjected to a first extraction at 20° C. for 12 h using a mass ratio of the first extractant:lignite particles of 3:1, followed by filtration to obtain a first solid phase and a first liquid phase;

[0067] (2) rotary evaporating the first liquid phase to obtain lignite resin and a first extraction vapor; the first extraction vapor is condensed and collected, the ratio of each component therein is detected, and each component is added to the first base solvent (ethyl acetate): additive A (acetic acid): additive B (tetrahydrofuran) in a mass ratio of 76:14:10 to obtain a first extractant, and returning to step (1);

[0068] (3) The second extractant is prepared according to the mass ratio of the second base solvent (ethyl acetate): water: additive A (acetic acid): additive B (tetrahydrofuran): additive C (sorbitol tristearate) = 30.36:60:5.6:4:0.04. The second extractant is added to the first solid phase in a circulating spraying manner at a volume ratio of the second extractant: first solid phase = 3:1 at 80°C, and the wax-rich liquid (the second extractant containing montan wax, the same below) is stirred at a stirring speed of 5000 r / min for 2 hours, and the first solid phase is subjected to a second extraction, and then filtered to obtain a second solid phase and a second liquid phase;

[0069] (4) The second solid phase is evaporated and desolventized at 140°C in a degassing machine to obtain defatted and dewaxed coal;

[0070] (5) Rotary evaporation of the second liquid phase to obtain lignite wax and a second extraction vapor; the second extraction vapor is condensed and collected, the ratio of each component therein is detected, and the ratio of each component is supplemented to a mass ratio of the second base solvent (ethyl acetate): water: additive A (acetic acid): additive B (tetrahydrofuran): additive C (sorbitol polyether tristearate) = 30.36:60:5.6:4:0.04 to obtain a second extractant, and return to step (3).

[0071] The extraction efficiency and total extraction efficiency of lignite resin and montan wax are shown in Table 1, and the contents of relevant components of lignite resin and montan wax are shown in Table 2.

[0072] Example 2

[0073] (1) The extractant is prepared in a mass ratio of the first base solvent (propyl acetate): additive A (acetic acid): additive B (pyridine) = 60:30:10. 500 g of lignite particles with a water content of 25 wt% are taken and subjected to a first extraction at a mass ratio of extractant:lignite particles of 3:1, allowed to stand at 25°C for 12 hours, and then filtered to obtain a first solid phase and a first liquid phase;

[0074] (2) rotary evaporating the first liquid phase to obtain lignite resin and a first extraction vapor; the first extraction vapor is condensed and collected, the ratio of each component therein is detected, and each component is added to the first base solvent (propyl acetate): additive A (acetic acid): additive B (pyridine) in a mass ratio of 60:30:10 to obtain a first extractant, and returning to step (1);

[0075] (3) The second extractant is prepared according to the mass ratio of the second base solvent (propyl acetate): water: additive A (butyric acid): additive B (pyridine): additive C (ethyl laurate) = 30:50:14.975:5:0.025. The second extractant is added to the first solid phase in a circulating spraying manner at a volume ratio of the second extractant: first solid phase = 3:1 at 80°C, and the wax-rich liquid is stirred at a stirring speed of 5000 r / min for 4 hours. The first solid phase is subjected to a second extraction and then filtered to obtain a second solid phase and a second liquid phase;

[0076] (4) the second solid phase is subjected to evaporation and desolventization at 140° C. in a degassing machine to obtain defatted and dewaxed coal;

[0077] (5) Rotary evaporation of the second liquid phase to obtain lignite wax and a second extraction vapor; the second extraction vapor is condensed and collected, the ratio of each component therein is detected, and the ratio of each component is supplemented to the mass ratio of the second base solvent (propyl acetate): water: additive A (butyric acid): additive B (pyridine): additive C (ethyl laurate) = 30:50:14.975:5:0.025 to obtain a second extractant, and return to step (3).

[0078] The extraction efficiency and total extraction efficiency of lignite resin and montan wax are shown in Table 1, and the contents of relevant components of lignite resin and montan wax are shown in Table 2.

[0079] Example 3

[0080] (1) The first extractant is prepared according to the mass ratio of the first base solvent (toluene): additive A (ethylenediamine): additive B (N-methyl-2-pyrrolidone) = 90:5:5, 500 g of lignite particles with a water content of 15 wt% are taken, and the first extraction is performed at a mass ratio of the extractant: lignite particles of 3:1 at 15° C. for 12 h, and then filtered to obtain a first solid phase and a first liquid phase;

[0081] (2) rotary evaporating the first liquid phase to obtain lignite resin and a first extraction vapor; the first extraction vapor is condensed and collected, the ratio of each component therein is detected, and each component is added to the first base solvent (toluene): additive A (ethylenediamine): additive B (N-methyl-2-pyrrolidone) in a mass ratio of 76:14:10 to obtain a first extractant, and returning to step (1);

[0082] (3) The second extractant is prepared according to the mass ratio of the second base solvent (toluene): water: additive A (ethylenediamine): additive B (N-methyl-2-pyrrolidone): additive C (dodecyldimethylamine betaine) = 53.994:40:3:3:0.006. The second extractant is added to the first solid phase in a circulating spraying manner at a volume ratio of the second extractant: first solid phase = 3:1 at 80°C, and the wax-rich liquid is stirred at a stirring speed of 5000 r / min for 1 hour. The first solid phase is subjected to a second extraction, and then filtered to obtain a second solid phase and a second liquid phase;

[0083] (4) The second solid phase is evaporated and desolventized at 140°C in a degassing machine to obtain defatted and dewaxed coal;

[0084] (5) Rotary evaporation of the second liquid phase to obtain lignite wax and a second extraction vapor; the second extraction vapor is condensed and collected, the ratio of each component therein is detected, and the ratio of each component is supplemented to the second base solvent (toluene): water: additive A (ethylenediamine): additive B (N-methyl-2-pyrrolidone): additive C (dodecyldimethylamine ethyl lactone) = 53.994:40:3:3:0.006 to obtain a second extractant, and return to step (3).

[0085] The extraction efficiency and total extraction efficiency of lignite resin and montan wax are shown in Table 1, and the contents of relevant components of lignite resin and montan wax are shown in Table 2.

[0086] Example 4

[0087] (1) The first extractant is prepared according to the mass ratio of the first base solvent (cyclohexane): additive A (butyric acid): additive B (cyclohexanone) = 50:25:25, 500 g of raw coal with a water content of 15 wt% is taken, and the first extraction is performed at a mass ratio of the extractant: lignite particles of 3:1 at 20° C. for 12 hours, and then filtered to obtain a first solid phase and a first liquid phase;

[0088] (2) rotary evaporating the first liquid phase to obtain lignite resin and a first extraction vapor; the first extraction vapor is condensed and collected, the ratio of each component therein is detected, and each component is added to the first base solvent (cyclohexane): additive A (butyric acid): additive B (cyclohexanone) in a mass ratio of 50:25:25 to obtain a first extractant, and returning to step (1);

[0089] (3) The second extractant is prepared according to the second base solvent (cyclohexane): water: additive A (butyric acid): additive B (cyclohexanone): additive C (sorbitol polyether tristearate) = 34.895:30:17.5:17.5:0.105. The second extractant is added to the first solid phase in a circulating spraying manner at a volume ratio of the second extractant to the first solid phase = 3:1 at 80°C, and the wax-rich liquid is stirred at a stirring speed of 5000 r / min for 0.5 h. The first solid phase is subjected to a second extraction, and then filtered to obtain a second solid phase and a second liquid phase;

[0090] (4) The second solid phase is evaporated and desolventized at 140°C in a degassing machine to obtain defatted and dewaxed coal;

[0091] (5) Rotary evaporation of the second liquid phase to obtain lignite wax and a second extraction vapor; the second extraction vapor is condensed and collected, the ratio of each component therein is detected, and the ratio of each component is supplemented to the second base solvent (cyclohexane): water: additive A (butyric acid): additive B (cyclohexanone): additive C (sorbitol polyether tristearate) = 34.895:30:17.5:17.5:0.105 to obtain a second extractant, and return to step (3).

[0092] The extraction efficiency and total extraction efficiency of lignite resin and montan wax are shown in Table 1, and the contents of relevant components of lignite resin and montan wax are shown in Table 2.

[0093] Example 5

[0094] (1) The first extractant is prepared according to a mass ratio of the first base solvent (n-heptane): additive A (propionic acid): additive B (pyridine) = 76:14:10. 500 g of lignite particles with a 10 wt% water content are taken and subjected to a first extraction at a mass ratio of extractant:lignite particles = 3:1 at 20°C for 12 hours, followed by filtration to obtain a first solid phase and a first liquid phase;

[0095] (2) rotary evaporating the first liquid phase to obtain lignite resin and a first extraction vapor; the first extraction vapor is condensed and collected, the ratio of each component therein is detected, and the ratio of each component is supplemented to a mass ratio of the first base solvent (n-heptane): additive A (propionic acid): additive B (pyridine) = 76:14:10 to obtain a first extractant, and returning to step (1);

[0096] (3) The second extractant is prepared according to the mass ratio of the second base solvent (n-heptane): additive A (propionic acid): additive B (pyridine) = 76:14:10. The second extractant is added to the first solid phase in a circulating spraying manner at a volume ratio of the second extractant to the first solid phase = 3:1 at 80°C, and the wax-rich liquid is stirred at a stirring speed of 5000 r / min for 2 hours. The first solid phase is subjected to a second extraction and then filtered to obtain a second solid phase and a second liquid phase;

[0097] (4) The second solid phase is evaporated and desolventized at 140°C in a degassing machine to obtain defatted and dewaxed coal;

[0098] (5) Rotating the second liquid phase to obtain lignite wax and a second extraction vapor; the second extraction vapor is condensed and collected, and the ratio of each component therein is detected, and the ratio of each component is supplemented to a mass ratio of the second base solvent (n-heptane): additive A (propionic acid): additive B (pyridine) = 76:14:10 to obtain a second extractant, and returning to step (3).

[0099] The extraction efficiency and total extraction efficiency of lignite resin and montan wax are shown in Table 1, and the contents of relevant components of lignite resin and montan wax are shown in Table 2.

[0100] Example 6

[0101] Lignite resin and montan wax were obtained in the manner of Example 1, except that the second extractant was prepared according to the mass ratio of the first base solvent (ethyl acetate): additive A (acetic acid): additive B (tetrahydrofuran) = 76:14:10.

[0102] The extraction efficiency and total extraction efficiency of lignite resin and montan wax are shown in Table 1, and the contents of relevant components of lignite resin and montan wax are shown in Table 2.

[0103] Comparative Example 1

[0104] Lignite resin and montan wax were obtained in the same manner as in Example 1, except that toluene was used as both the first extractant and the second extractant.

[0105] The extraction efficiency and total extraction efficiency of lignite resin and montan wax are shown in Table 1, and the contents of relevant components of lignite resin and montan wax are shown in Table 2.

[0106] Comparative Example 2

[0107] Lignite resin and montan wax were obtained in the manner of Example 1, except that the first extractant was prepared according to a mass ratio of the first base solvent (ethyl acetate) to the additive A (acetic acid) of 84:16.

[0108] The extraction efficiency and total extraction efficiency of lignite resin and montan wax are shown in Table 1, and the contents of relevant components of lignite resin and montan wax are shown in Table 2.

[0109] Comparative Example 3

[0110] Lignite resin and montan wax were obtained in the manner of Example 1, except that the second extractant was prepared according to the mass ratio of the second base solvent (ethyl acetate): water: additive C (sorbitol tristearate) = 30.32:66.63:0.05.

[0111] The extraction efficiency and total extraction efficiency of lignite resin and montan wax are shown in Table 1, and the contents of relevant components of lignite resin and montan wax are shown in Table 2.

[0112] Comparative Example 4

[0113] Lignite resin and montan wax were obtained in the manner of Example 1, except that the second extractant was prepared according to the mass ratio of the second base solvent (ethyl acetate): water: additive A (acetic acid): additive B (tetrahydrofuran) = 30.4:60:5.6:4.

[0114] The extraction efficiency and total extraction efficiency of lignite resin and montan wax are shown in Table 1, and the contents of relevant components of lignite resin and montan wax are shown in Table 2.

[0115] Table 1

[0116]

[0117]

[0118] Table 2

[0119]

[0120] As can be seen from the results in Table 1, the use of the multi-extractant of the present invention can significantly improve the extraction efficiency of lignite wax and lignite resin, reduce the amount of organic solvent used, and improve environmental benefits. The results of Example 1 and Comparative Example 1 show that, under the same extraction method, the use of the multi-extractant of the present invention increases the extraction efficiency of lignite wax by 38.8% and the extraction efficiency of lignite resin by 24.7%. The results of Example 1 and Comparative Example 2 show that the base solvent, additive A, and additive B in the first extractant have a synergistic effect, which can increase the extraction efficiency of lignite resin and lignite wax. The results of Example 1, Comparative Example 3, and Comparative Example 4 show that when the second extractant uses Extractant II, the base solvent, additive A, additive B, and additive C have a synergistic effect, which can improve the extraction efficiency of lignite wax. The results of Examples 1 and 6 show that when the water content of the raw lignite is high, when the amount of the second extractant is the same, the extraction efficiency of lignite wax is higher and the extraction effect is better when Extractant II is used as the second extractant. It can be seen from Table 1 and Table 2 that the use of the extractant and method of the present invention can produce high-purity lignite resin and low-resin content lignite wax, and the extraction efficiency of lignite wax and lignite resin is high.

[0121] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for extracting lignite wax and lignite resin from lignite, characterized in that: The method includes: (1) contacting lignite particles with a first extractant to perform a first extraction, and then performing a first solid-liquid separation to obtain a first liquid phase and a first solid phase; wherein the temperature of the first extraction is 15-35° C.; (2) subjecting the first liquid phase to a first steaming treatment to obtain first extractant vapor and lignite resin; (3) mixing the first solid phase with a second extractant to perform a second extraction, and then performing a second solid-liquid separation to obtain a second liquid phase and a second solid phase; wherein the temperature of the second extraction is 70-90°C; (4) subjecting the second liquid phase to a second steaming treatment to obtain second extractant vapor and montan wax; Wherein, the first extractant is extractant I containing a first base solvent, additive A and additive B, The second extractant is an extractant II containing a second base solvent, water, additive A, additive B and additive C; Wherein, the additive A is selected from at least one of acetic acid, propionic acid, butyric acid, and ethylenediamine; Wherein, the additive B is selected from at least one of pyridine, tetrahydrofuran, cyclohexanone, and N-methyl-2-pyrrolidone; Wherein, the additive C is selected from at least one of ethyl laurate, sorbitol polyether tristearate, and dodecyl dimethylamino betaine; The first base solvent and the second base solvent are each selected from at least one of benzene compounds, ester compounds, and hydrocarbon compounds.

2. The method according to claim 1, wherein Based on the total amount of the extractant I, the content of the first base solvent in the extractant I is 50-95wt%, the content of the additive A is 1-30wt%, and the content of the additive B is 1-30wt%; And / or, based on the total amount of the extractant II, the content of the second base solvent in the extractant II is 30-67 wt %, the content of water is 30-60 wt %, the content of the additive A is 1-20 wt %, the content of the additive B is 1-18 wt %, and the content of the additive C is 0.005-0.15 wt %.

3. The method according to claim 1, wherein The ester compound is ethyl acetate and / or propyl acetate, the benzene compound is toluene, and the hydrocarbon compound is cyclohexane and / or n-heptane.

4. The method according to claim 1, wherein The particle size of the lignite particles is 1-10 mm.

5. The method according to claim 1 or 4, wherein The moisture content of the lignite particles is 10-50 wt %.

6. The method according to claim 1, wherein The mass ratio of the first extractant to the lignite particles is (2-3):1, and the first extraction time is 4-12 hours.

7. The method according to claim 1, wherein The volume ratio of the second extractant to the first solid phase is (2-4):1, and the second extraction time is 0.5-4 hours.

8. The method according to claim 1, wherein The method further comprises recovering the first extractant vapor and the second extractant vapor respectively, and returning the vapors to step (1) and step (3) respectively.

9. Use of the method according to any one of claims 1 to 8 in extracting lignite wax and lignite resin from lignite.

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