Method for adding back extractant in extraction and back extraction separation process of coal characteristic family components

Abstract

The invention discloses a method for adding a back-extractant in the process of extracting and back-extracting and separating coal characteristic group components. The method comprises the following steps: firstly, measuring the maximum thickness Y of a gelatinous layer of a raw material coal sample, the caking index GR.I of the raw material coal sample and the dry ash-free volatile component Vdaf of the raw material coal sample; then, the adding amount of the back-extractant is calculated through a calculation formula; in the formula, W is the adding amount of the back-extractant, mL; sm is the addition amount of the extraction agent, mL; y is the maximum thickness of the gelatinous layer of the raw material coal, mm; gR.I is the caking index of the feed coal; vdaf is a dry ash-free basis volatile component of the feed coal,%. According to the method, the specific adding amount of the back extractant can be directly calculated according to three national standard test indexes, namely the volatile component content, the maximum gelatinous layer thickness and the caking index, of the coking coal, the method is simple, practical and easy to implement, the separation effect and the separation working efficiency are greatly improved, and the problem of effective precipitation of dense and medium components in different coal types is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of separation of coal characteristic group components, and in particular relates to a method for adding a stripping agent in the process of extracting and stripping to separate coal characteristic group components. Background Art

[0002] At present, regarding the extraction and stripping separation method of coal group components, the patent with the prior art publication number CN101070495 discloses a mild coal group component separation method based on extraction and stripping, and the separation process steps of the method are: adding a mixed solvent (solvent A + solvent B) as an extractant to the coal sample, stirring, and obtaining an extracted solid-liquid mixture; performing solid-liquid separation on the extracted solid-liquid mixture to obtain an extract and a residue (also called a coal heavy group) respectively; washing the residue with water, and then vacuum drying to obtain a residue coal; adding solvent C as a stripping agent to the extract, stirring, obtaining a stripped solid-liquid mixture and performing solid-liquid separation on it. The solid material (also called the coal loose medium group) and the liquid material are obtained; the solid material is washed with water and dried to obtain clean coal; the liquid material is divided into two layers: the upper layer solution is mainly a mixture of solvent B and solvent C; the lower layer solution mainly contains solvent A and a small amount of solvent B. Solvent A is removed by atmospheric distillation to obtain a viscous residue, which is mainly an asphaltene component (also called a coal dense medium group) and a small amount of solvent B. After the viscous residue is transferred out, it needs to be subjected to the next process treatment to precipitate the coal dense medium group. In this process treatment, the viscosity of the viscous residue must be within a certain moderate range to be achieved.

[0003] However, the patent technical solution only provides that the amount of stripping agent added for the first use is "according to the volume ratio between the extract and the stripping agent of 1:0.1 to 1:2", and its specific cases also only introduce a limited number of cases, for example: "The stripping agent used is water, and the amount of stripping agent added is equal to 1:1, 1:2, 1:0.2, 1:0.1, 1:1.1 according to the ratio of the remaining solution to the stripping agent", and there is no further study on the adverse effects of different amounts of stripping agent added on subsequent operations.

[0004] Since the amount of dense coal medium mass group contained in different types of coal is different, therefore, after removing solvent A from the lower solution and then subjecting the viscous residue to the next process to precipitate the dense medium mass group, the inventor believes that the amount of stripping agent added for the first time in the process will affect the fluidity or viscosity of the viscous residue. If the amount of stripping agent added is too little, the viscous residue is too thin and cannot be processed in the next step. If the amount of stripping agent added is too much, the viscous residue is too thick, which is mainly manifested as easy adhesion to the container wall, which makes it difficult to transfer the viscous residue for the next step of processing, thereby affecting the separation effect. Therefore, for different types of coal, it is necessary to adjust the amount of stripping agent added for the first time to achieve the fluidity or viscosity of the above-mentioned viscous residue in a suitable range. At present, there is no literature report on obtaining the amount of stripping agent added according to the corresponding characteristic data of different types of coal. Summary of the invention

[0005] The purpose of the present invention is to solve the problem of fluidity of viscous residue after extraction, and provide a method for adding a stripping agent in the process of extracting and stripping to separate coal characteristic group components. The method is simple and easy to implement, and can obtain the amount of stripping agent added by calculation according to the corresponding characteristic data (volatile matter content, maximum colloid layer thickness, bonding index) of different types of coal, thereby effectively improving the separation effect of coal dense medium mass group in different types of coal.

[0006] To achieve the above-mentioned purpose of the invention, the present invention provides a method for adding a stripping agent during extraction and stripping to separate coal characteristic group components, the steps comprising:

[0007] ①, placing the coal sample in an extractor, and then adding a mixed solvent, the amount of which is 20-300 ml per gram of coal sample, the mixed solvent being a mixture of solvent A and solvent B; the extraction process is completed, and an extracted solid-liquid mixture is obtained; the mixed solvent comprises solvent A and solvent B, the mixing ratio of solvent A to solvent B is between 1:0.2 and 1:2, and the mixing ratio is a volume ratio;

[0008] ②, performing solid-liquid separation on the solid-liquid mixture extracted in process ①, and obtaining an extract and a residue after solid-liquid separation respectively;

[0009] ③. Treat the residue in process ② by washing with water and then vacuum drying to obtain the residue coal;

[0010] ④, treating the extract in process ②, placing the extract into a stripper, and then adding a stripping agent into the stripper, the stripping process is completed, and a stripping solid-liquid mixture is obtained after the stripping process;

[0011] ⑤. Treat the back-extracted solid-liquid mixture in process ④, perform solid-liquid separation on the back-extracted solid-liquid mixture, and obtain solid matter and liquid matter after solid-liquid separation;

[0012] ⑥. Treat the solid matter in process ⑤ by washing it with water and then vacuum drying it to obtain clean coal;

[0013] ⑦. The liquid substance obtained in process ⑤ is two layers of liquid substances: one layer of liquid substance is mainly composed of solvent A. After removing the layer, solvent A is first removed by atmospheric distillation, and then the remaining solution is stripped with a stripping agent. The stripping agent strips out a small amount of solvent B in the remaining solution and produces viscous solid precipitation. The viscous substance is vacuum dried to obtain the bonding component in the coal;

[0014] The other layered liquid substance is mainly a mixture of solvent B and stripping agent.

[0015] The solvent A is one of carbon disulfide, chloroform, dichloromethane, benzene, methanol, phenol and ether:

[0016] The solvent B is one of: N-methyl-2-pyrrolidone, cyclohexanone, dimethyl sulfoxide, tetrahydrofuran, dimethylformamide, dimethylacetamide, ethylenediamine, triethyl phosphate, quinoline, and pyridine;

[0017] The stripping agent is solvent C, and the solvent C is water;

[0018] In the same process, three different solvent substances must be selected for solvent A, solvent B and solvent C;

[0019] It is characterized in that: in step ④, the amount of stripping agent added is calculated according to the following method:

[0020] First, the maximum thickness Y of the colloid layer of the raw coal sample and the bonding index G of the raw coal sample are determined. R.I and the dry ash-free volatile matter V of the raw coal sample daf ; Then the amount of stripping agent added is calculated by formula (I);

[0021]

[0022] In formula (I): W is the amount of stripping agent added, mL; S m is the amount of extractant added, mL; Y is the maximum thickness of the raw coal colloid layer, mm; G R.I V is the raw coal cohesion index; daf The volatile matter of the raw coal is dry ash-free basis, %.

[0023] Furthermore, the maximum thickness Y of the raw coal colloidal layer is measured according to the national standard GB / T 479-2016.

[0024] Furthermore, the raw coal cohesion index G R.I It is measured according to the national standard GB / T 5447-2014.

[0025] Furthermore, the raw coal dry ash-free volatile matter V daf It is measured according to the national standard GB / T 212-2008.

[0026] Preferably, the solvent A is carbon disulfide, and the solvent B is N-methyl-2-pyrrolidone.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention only needs to directly calculate and determine the specific amount of the first stripping agent to be added based on the three national standard test indicators of the raw coal, namely, the volatile matter content, the maximum colloid layer thickness, and the bonding index, so that the viscous solid obtained after stripping has a relatively moderate fluidity, which lays a good foundation for the next operation process. The method is simple, practical and easy to implement, greatly improves the separation effect and separation work efficiency, and solves the problem of effective precipitation of dense medium-quality groups in different types of coal. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the prior art CN200710022120.1 disclosed a mild coal group component separation method based on extraction and back extraction and specific examples.

[0030] The specific steps are as follows:

[0031] ①. Place a coal sample with a particle size of 10-300 mesh in an extractor, and then add a mixed solvent in an amount of 20-300 ml of mixed solvent per gram of coal sample, wherein the mixed solvent is a mixture of solvent A and solvent B; stir at room temperature for 10-300 minutes, and the extraction process is completed to obtain an extracted solid-liquid mixture;

[0032] ②, performing solid-liquid separation on the solid-liquid mixture extracted in process ①, and obtaining an extract and a residue after solid-liquid separation respectively;

[0033] ③. Treat the residue in process ② by washing with water and then vacuum drying to obtain the residue coal;

[0034] ④. Treat the extract in process ②, put the extract into a stripper, and then add a stripping agent into the stripper. The stripping agent is determined by the characteristics of the raw coal. The volume ratio of the extract to the stripping agent is 5-60 minutes at room temperature. The stripping process is completed, and a stripping solid-liquid mixture is obtained after the stripping process;

[0035] ⑤. Treat the back-extracted solid-liquid mixture in process ④, perform solid-liquid separation on the back-extracted solid-liquid mixture, and obtain solid matter and liquid matter after solid-liquid separation;

[0036] ⑥. Treat the solid matter in process ⑤ by washing it with water and then vacuum drying it to obtain clean coal;

[0037] ⑦. The liquid substance obtained in process ⑤ is a liquid substance of two layers: the lower layer liquid substance is mainly solvent A, the liquid substance of this layer is removed and solvent A is removed by atmospheric distillation, and then the remaining solution is stripped with a stripping agent to strip a small amount of solvent B, the amount of stripping agent added is 1:0.1 to 1:2 according to the ratio of the remaining solution to the stripping agent, and the solution to the stripping agent is a volume ratio. When the stripping agent strips out a small amount of solvent B in the remaining solution, a viscous solid is precipitated, and the viscous solid is vacuum dried to obtain the bonding component in the coal;

[0038] The other layered liquid substance is mainly a mixture of solvent B and stripping agent.

[0039] The mixing ratio of solvent A to solvent B is between 1:0.2 and 1:2, and the mixing ratio is a volume ratio.

[0040] The solvent A is one of carbon disulfide, chloroform, dichloromethane, benzene, methanol, phenol and ether:

[0041] The solvent B is one of: N-methyl-2-pyrrolidone, cyclohexanone, dimethyl sulfoxide, tetrahydrofuran, dimethylformamide, dimethylacetamide, ethylenediamine, triethyl phosphate, quinoline, and pyridine;

[0042] The stripping agent is solvent C, and the solvent C is water;

[0043] In the same process, three different solvent substances must be selected for solvent A, solvent B and solvent C;

[0044] In step ④, the amount of stripping agent added is calculated according to the following method: Example 1,

[0045] A method for calculating the amount of stripping agent added in the process of extracting and stripping to separate coal characteristic group components. In the process of extracting and stripping to separate coal characteristic group components, the mass of coking coal A is 10g, the extractant is a mixed solvent CS2 / NMP with a volume ratio of 1:1, and the amount of extractant added S m The volume is 1000 mL, and the stripping agent is water;

[0046] First, according to the national standards GB / T 479-2016, GB / T 5447-2014 and GB / T212-2008, the maximum thickness Y of the colloid layer of coking coal A is 15 mm, the bonding index G of coking coal A is 15 mm, and the bonding index G of coking coal A is 15 mm. R.I The dry ash-free volatile matter V of 85 and coking coal A daf is 20%; then the amount of stripping agent added is calculated by formula (I) to be 1015.72 mL; the viscous residue formed in the process has a viscosity of 186 cP, does not stick to the container wall, and has good flow properties; the next step of the process precipitates the dense medium group smoothly, and the amount of dense medium group precipitated is 6.35% (daf).

[0047]

[0048] Example 2

[0049] A method for calculating the amount of stripping agent added in the process of extracting and stripping to separate coal characteristic group components. In the process of extracting and stripping to separate coal characteristic group components, the mass of coking coal B is 10g, the extractant is a mixed solvent CS2 / NMP with a volume ratio of 1:1, and the amount of extractant added S m The volume is 1000 mL, and the stripping agent is water;

[0050] First, according to the national standards GB / T 479-2016, GB / T 5447-2014 and GB / T212-2008, the maximum thickness Y of the colloid layer of coking coal B is 21 mm, the bonding index G of coking coal B is 21 mm, and the bonding index G of coking coal B is 21 mm. R.I The dry ash-free volatile matter V of 85 and coking coal B daf is 33%; then the amount of stripping agent added is calculated by formula (I) to be 936.74 mL; the viscous residue formed in the process has a viscosity of 198 cP, does not stick to the container wall, and has good flow properties; the next step of the process precipitates the dense medium group smoothly, and the amount of dense medium group precipitated is 18.96% (daf).

[0051]

[0052] Example 3

[0053] A method for calculating the amount of stripping agent added in the process of extracting and stripping to separate coal characteristic group components. In the process of extracting and stripping to separate coal characteristic group components, the mass of coking coal C is 10g, the extractant is a mixed solvent CS2 / NMP with a volume ratio of 1:1, and the amount of extractant added S m The volume is 1000 mL, and the stripping agent is water;

[0054] Firstly, the maximum thickness Y of the colloid layer of coking coal C is 29 mm, the bonding index G of coking coal C is 29 mm, and the bonding index G of coking coal C is 29 mm. R.I The dry ash-free volatile matter V of coking coal C is 90 daf It is 36.26%; then the amount of stripping agent added is calculated by formula (I) to be 907.64mL; the viscous residue formed in the process has a viscosity of 190cP, does not stick to the container wall, and has good flowability; the next step of the process precipitates the dense medium group smoothly, and the amount of dense medium group precipitated is 12.43% (daf).

[0055]

[0056] Example 4

[0057] A method for calculating the amount of stripping agent added in the process of extracting and stripping to separate coal characteristic group components. In the process of extracting and stripping to separate coal characteristic group components, the mass of coking coal D is 10g, the extractant is a mixed solvent CS2 / NMP with a volume ratio of 1:1, and the amount of extractant added S m The volume is 1000 mL, and the stripping agent is water;

[0058] First, according to the national standards GB / T 479-2016, GB / T 5447-2014 and GB / T212-2008, the maximum thickness Y of the colloid layer of coking coal D is 27.5 mm, the bonding index G of coking coal D is 27.5 mm, and the bonding index G of coking coal D is 27.5 mm. R.I The dry ash-free volatile matter V of coking coal D is 95 daf It is 29.21%; then the amount of stripping agent added is calculated by formula (I) to be 891.73 mL; the viscous residue formed in the process has a viscosity of 193 cP, does not stick to the container wall, and has good flowability; the next step of the process precipitates the dense medium group smoothly, and the amount of dense medium group precipitated is 12.50% (daf).

[0059]

Claims

1. A method for adding a stripping agent during extraction and stripping to separate coal characteristic group components, comprising the steps of: ①, placing the coal sample in an extractor, and then adding a mixed solvent, the amount of which is 20-300 ml per gram of coal sample, the mixed solvent being a mixture of solvent A and solvent B; the extraction process is completed, and an extracted solid-liquid mixture is obtained; the mixed solvent comprises solvent A and solvent B, the mixing ratio of solvent A to solvent B is between 1:0.2 and 1:2, and the mixing ratio is a volume ratio; ②, performing solid-liquid separation on the solid-liquid mixture extracted in process ①, and obtaining an extract and a residue after solid-liquid separation respectively; ③. Treat the residue in process ② by washing with water and then vacuum drying to obtain the residue coal; ④, treating the extract in process ②, placing the extract into a stripper, and then adding a stripping agent into the stripper, the stripping process is completed, and a stripping solid-liquid mixture is obtained after the stripping process; ⑤. Treat the back-extracted solid-liquid mixture in process ④, perform solid-liquid separation on the back-extracted solid-liquid mixture, and obtain solid matter and liquid matter after solid-liquid separation; ⑥. Treat the solid matter in process ⑤ by washing it with water and then vacuum drying it to obtain clean coal; ⑦. The liquid substance obtained in process ⑤ is two layers of liquid substances: one layer of liquid substance is mainly composed of solvent A. After removing the layer, solvent A is first removed by atmospheric distillation, and then the remaining solution is stripped with a stripping agent. The stripping agent strips out a small amount of solvent B in the remaining solution and produces viscous solid precipitation. The viscous substance is vacuum dried to obtain the bonding component in the coal; Another layer of liquid material is mainly a mixture of solvent B and stripping agent, The solvent A is one of carbon disulfide, chloroform, dichloromethane, benzene, methanol, phenol and ether: The solvent B is one of: N-methyl-2-pyrrolidone, cyclohexanone, dimethyl sulfoxide, tetrahydrofuran, dimethylformamide, dimethylacetamide, ethylenediamine, triethyl phosphate, quinoline, and pyridine; The stripping agent is solvent C, and the solvent C is water; In the same process, three different solvent substances must be selected for solvent A, solvent B and solvent C; It is characterized in that: in step ④, the amount of stripping agent added is calculated according to the following method: First, the maximum thickness Y of the colloid layer of the raw coal sample and the bonding index G of the raw coal sample are determined. R.I and the dry ash-free volatile matter V of the raw coal sample daf ; Then the amount of stripping agent added is calculated by formula (I); In formula (I): W is the amount of stripping agent added, mL; S m is the amount of extractant added, mL; Y is the maximum thickness of the raw coal colloid layer, mm; G R.I V is the raw coal cohesion index; daf The volatile matter of the raw coal is dry ash-free basis, %.

2. The method for adding a stripping agent in the process of extraction and stripping to separate the characteristic group components of coal according to claim 1, characterized in that: The maximum thickness Y of the raw coal colloid layer is measured according to the national standard GB / T479-2016.

3. The method for adding a stripping agent in the process of extraction and stripping to separate the characteristic group components of coal according to claim 1, characterized in that: The raw coal adhesion index G R.I It is measured according to the national standard GB / T5447-2014.

4. The method for adding a stripping agent in the process of extraction and stripping to separate the characteristic group components of coal according to claim 1, characterized in that: The dry ash-free volatile matter V of the raw coal daf It is measured according to the national standard GB / T 212-2008.

5. The method for calculating the amount of stripping agent added in the process of extraction and stripping to separate coal characteristic group components according to claim 1, characterized in that: The solvent A is carbon disulfide, and the solvent B is N-methyl-2-pyrrolidone.

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