WO2021008192A1

WO2021008192A1 - Research model for coal and construction method therefor

Info

Publication number: WO2021008192A1
Application number: PCT/CN2020/087867
Authority: WO
Inventors: 张继龙; 马永; 刘颖杰; 于盛旺; 张露雅
Original assignee: 太原理工大学
Priority date: 2019-07-12
Filing date: 2020-04-29
Publication date: 2021-01-21
Also published as: CN110376347B; CN110376347A

Abstract

A research model for coal and a construction method therefor. The invention employs the concept of tai chi to turn coal into tai-chi-coal particles. The coal particles comprise four substances: a pure organic substance; a pure mineral substance; a mineral-substance-containing organic substance; and an organic-substance-containing mineral substance. Arrangement and combination of the four substances form a basic research model for coal. The invention converts a complex coal structure to a tai-chi-coal particle model. This structural unit is applicable to various aspects, uses and research fields.

Description

A coal research model and its construction method

Technical field

The invention relates to a coal research model and a construction method thereof, and belongs to the technical field of coal research.

Background technique

The formation of coal is generally believed to be a fossil resource formed by the evolution of ancient plants in the underground through geological changes for more than 70 million years. The formation process is accompanied by the simultaneous mineralization of other materials, so that in the mining, coal is accompanied by minerals (also known as gangue), and even the phenomenon of lean coal and more minerals occurs. In coal processing and utilization, whether it is coal washing or coal deep processing (coal chemical industry), minerals are always accompanied by organic coal. Therefore, coal is recognized as a community of organic matter and inorganic minerals. However, the current research on the structure of coal is mainly based on the establishment of models for chemical utilization, and it is intended that the molecular structure of coal cannot be determined to be uniform. Chinese patent CN 104091504A discloses a method for building a coal structure model to understand the structure and properties of coal from a chemical point of view, and play a guiding role in the efficient conversion and utilization of coal. Chinese Patent CN 105138809A discloses the establishment of an analysis method for the void characteristics of amorphous bituminous coal structure. Chinese patent CN 106898220A discloses a new method for establishing a structural model of lignite. The model established by this method can reflect the characteristics of the formation of benzene carboxylic acid and its yield distribution during the oxidation process of lignite. Chinese patent CN 106169016A discloses a method for constructing a structural model of sulfur-containing macromolecules in coking coal, which plays a guiding role in developing model compounds to replace coal for microwave desulfurization. Chinese patent CN108088863A discloses a method for constructing a structural model of lignite organic macromolecules without damage. The above methods are based on the current development of computer technology and the development of coal chemistry and chemical engineering. Various characterization methods (such as ¹³ C NMR, HRTEM, X-ray, FT-IR, etc.) are used to study various reactions of coal. Performance model.

There is still a gap between the ideal and simplified conception of model establishment and actual micro-research. For example, only C, H, O, N and S elements are considered in the model construction, and only the micropores and gaps constructed by bulk molecules in the molecular structure, while the actual coal molecules and mineral molecules are co-occurring (associated). The structure of coal There are many mesopores and macropores in the determination. Coal is a heterogeneous organic sedimentary rock, which is composed of multi-component, macromolecular organic matter and a variety of inorganic minerals. In short, coal is a mixture of organic and inorganic phases. Zeng Fangui et al. (The concept of coal supramolecular structure and its research methods and methods[J]. Journal of China Coal Society,2005,30(1):85-89) proposed the concept of coal supramolecular structure, and believed that coal supramolecular structure is mainly reflected in coal The physical and chemical mechanisms of molecular composition and structure, interaction between molecules, molecular recognition and formation. So far, most research has focused on the concept of organic molecular structure of coal, covering coal chemical industry, coalbed methane and other fields.

In the field of coal flotation, the basic research unit concept of coal has not yet been proposed. We believe that the concept of coal molecules in coal preparation should be studied in conjunction with minerals. Flotation is the process of separating inorganic minerals and organic coal to obtain clean coal. Due to the complex lithofacies structure of coal, the uneven distribution of minerals and organic matter, and the functional groups (oxygen, sulfur, nitrogen, etc.) contained on the surface of coal particles, the established models can basically not solve the basic unit problem of studying coal.

Summary of the invention

The invention aims to provide a coal research model and its construction method. Its purpose is to solve the general problem of researching the basic unit of coal, specifically to establish a basic unit particle that reflects the coexistence of organic matter and inorganic matter in the coal composition, and simultaneously solves the problem Practical problems with minerals in coal processing and utilization.

The present invention provides a coal research model, using the concept of Tai Chi to make coal into Tai Chi coal particles. The coal particles contain four parts: one part is pure organic matter, one part is pure minerals, and one part is organic matter containing minerals. The substance and one part are minerals which contain organic matter. The permutation and combination of the four parts form the basic research model of coal.

Furthermore, organic matter accounts for 1-100% of coal particles, and minerals account for 0-99% of coal particles (ultra-pure coal has no minerals or the percentage of minerals is close to 0).

The present invention provides a method for constructing the aforementioned coal research model, which includes the following steps:

(1) First-level crushing of coal particles to a particle size of 3mm or less; the equipment used in the first-level crushing is jaw crusher, hammer crusher, counter-roll crusher, rod mill, and ball mill. One kind

Then, the secondary crushing is performed to grind the coal to a particle size of ≤10 μm; the equipment used for the secondary crushing is one of a jet mill, an ultrasonic crushing device, and a diamond grinding disc;

(2) Study the surface properties of pulverized coal, including surface area, surface energy, and surface unevenness, to form a primitive particle model;

The surface area is measured by a nitrogen adsorption instrument, the surface energy is measured by a surface energy adsorption instrument, and the surface unevenness is measured by a coal rock microscope and a scanning electron microscope;

(4) One part is demineralized by hydrochloric acid, nitric acid, and concentrated hydrochloric acid to obtain ultra-pure coal (its ash content≤0.1%); another part is obtained by low-temperature plasma ashing (120-150℃) to obtain minerals (its ash content) Content ≥99.9%); Take two parts of samples and mix, shape, and press in proportion to make Tai Chi coal particles with a particle size of less than 0.1 mm.

The beneficial effects of the present invention:

The invention constructs a complex coal structure into a Tai Chi coal particle model. This structural unit can be applied in multiple angles, multiple uses, and multiple research fields; it is of great significance to study a universal coal structure method , And even subversive ideas and research innovations.

Description of the drawings

Figure 1 is a schematic diagram of the construction process of coal structure model.

Detailed ways

The following examples further illustrate the present invention, but are not limited to the following examples.

Example 1:

Taking 150 g of Jincheng anthracite coal, after industrial analysis, A _d = 21.1%, V _d = 12.3%, FC _d = 66.6%. Divide into A, B, and C each with 50g. The A sample is crushed by a ball mill and sieved with a 7-mesh (2.80mm) standard sieve to obtain an undersize sample of 48.9; then powdered with an ultrasonic pulverizer for 5 minutes, and then sieved with a 1340-mesh (10μm) standard sieve to obtain an undersize sample 5.3g, the sample on the sieve was pulverized with an ultrasonic pulverizer for 10 minutes, and then sieved with a 1340 mesh (10 μm) standard sieve to obtain 13.1 g of the undersize sample, and 18.4 g of the undersize sample was collected. In the same way, sample B was processed in the same way, and a total of 19.1 g of under-sieve samples were collected.

Put 18.4g of the sample under the A sieve into a 250mL three-necked flask, add 100mL hydrochloric acid (35%) and stir at 120℃ for 24 hours, then filter; add the filtered sample to a 250mL three-necked flask, add 100mL nitric acid and stir at 100℃ Filter after 10 hours; add the filtered sample to a 250mL three-necked flask, add 150mL of concentrated hydrochloric acid, stir at 160°C for 24 hours, filter, and dry in a vacuum drying oven at 75°C for 5 hours. Then ash was turned, and A _d =0.03% was measured. Put the 19.1gB sample under the sieve into the plasma ashing dish, and put about 1g in each ashing dish, and send the samples into the low-temperature plasma ashing instrument 19 times at 150℃ for 12 hours. Then, all the processed samples are mixed and ashed, and A _d =99.98% is measured.

Add 5g of the processed A sample and B sample at a ratio of 3.74:1 into the beaker. After ultrasonic treatment for 15 minutes, magnetically stir for 3 hours and mix well; then put it on the tablet press and adjust the pressure to 5MPa for molding; It is then crushed by a ball mill, and the undersize of a 7-mesh (2.80 mm) standard sieve is taken for industrial analysis. It is determined that A _d = 20.7%, V _d = 11.9%, and FC _d = 67.4%. In the same way, the C sample was mixed and stirred, compressed into tablets, and then ball milled and crushed. The under-sieve of a 7-mesh (2.80mm) standard sieve was taken for industrial analysis. It was determined that A _d = 21.0%, V _d = 12.1%, FC _d = 66.9%. By comparison, the data is within the error range, indicating that the properties of the prepared Tai Chi coal particles are completely consistent with the raw coal. The surface area, surface energy, surface unevenness, porosity and pore distribution are also measured. The comparison data is as follows:

样品sample	表面积(m ²/g) Surface area (m ² /g)	表面能(mJ/m ²) Surface energy (mJ/m ² )	粒度分布Particle size distribution	孔隙率(％)Porosity(%)	孔分布Pore distribution
A+B太极煤粒A+B Tai Chi coal particles	327327	7171	100μm(90％)100μm(90%)	3434	4.7nm4.7nm
C原煤粒C raw coal particles	330330	7272	100μm(90％)100μm(90%)	3535	5.0nm5.0nm

The present invention constructs a complex coal structure into a Tai Chi coal particle model. This structural unit can be applied in multiple angles, multiple uses, and multiple research fields; it can be seen from the above figure that the performance of the two is very close.

Industrial applicability

The invention has industrial applicability.

Claims

A coal research model, which is characterized by: adopting the concept of Tai Chi, the coal is made into Tai Chi coal particles. The coal particles contain four parts: one part is pure organic matter, one part is pure minerals, and one part contains minerals in organic matter. The substance and one part are minerals which contain organic matter. The permutation and combination of the four parts form the basic research model of coal.
The coal research model according to claim 1, characterized in that: the proportion of organic matter in coal particles is 1-100%, and the proportion of minerals in coal particles is 0-99%.
A method for constructing a coal research model according to claim 1 or 2, characterized in that it comprises the following steps:

(1) One-stage crushing of coal particles, crushed to a particle size below 3mm;

Then carry out secondary crushing and grind the coal to a particle size ≤10μm;

(2) Test the surface properties of the pulverized coal, including surface area, surface energy, and surface unevenness to form a primitive particle model;

(3) Chemical modification:

Research the pore distribution and porosity of coal powder, as well as the distribution of surface acid-base and functional groups, and obtain the modified elementary particle model;

(4) One part is demineralized by hydrochloric acid, nitric acid and concentrated hydrochloric acid to obtain ultra-pure coal. The ash content of ultra-pure coal is ≤0.1%; the other part is obtained by low-temperature plasma ashing to obtain minerals, and the ash content of the minerals ≥ 99.9%; Take two parts of samples and mix, shape, and press in proportion to make Tai Chi coal particles with a particle size of less than 0.1 mm.
The method for constructing a coal research model according to claim 3, characterized in that: in step (1), the equipment used in the primary crushing is a jaw crusher, a hammer crusher, a counter-roll crusher, and a rod crusher. One of mills and ball mills;

The equipment used in the secondary crushing is one of a jet mill, an ultrasonic crushing device, and a diamond grinding disc.
The method for constructing a coal research model according to claim 3, wherein in step (2), the surface area is measured by a nitrogen adsorption meter, the surface energy is measured by a surface energy adsorption meter, and the surface unevenness is measured by the coal Rock microscope or scanning electron microscope measurement.
The method for constructing a coal research model according to claim 3, wherein the temperature of the low-temperature plasma ashing is 120-150°C.