CN111766122A - Remolding structural coal sample material and sample preparation method - Google Patents

Abstract

The invention discloses a remolded tectonic coal sample material and a sample preparation method, which are suitable for detecting remolded tectonic coal samples. The mass portion ratio is that the coal powder with the grain diameter less than 5mm is 400-900 portions, the starch adhesive is 100 portions, the water is 50-150 portions, the alpha-amylase is 10-30 portions; the method comprises the steps of pressing tectonic coal powder, a natural cementing agent (starch glue or protein glue) and biological enzyme under certain forming pressure, curing and drying, decomposing the cementing agent by the biological enzyme, and finally obtaining a remolded tectonic coal sample in a laboratory. The formula is beneficial to manufacturing a stable and high-quality tectonic coal sample, improves the utilization rate of tectonic coal, effectively improves the working efficiency of a laboratory, and simultaneously manufactures a remolded tectonic coal sample without non-primitive biomass.

Description

Remolding structural coal sample material and sample preparation method

Technical Field

The invention relates to a remolded tectonic coal sample material and a sample preparation method, in particular to the remolded tectonic coal sample material and the sample preparation method which are suitable for researching coal samples.

Background

The tectonic coal is formed by the structural stress damage of the coal bed and the structural loss of the coal bed under the actions of extrusion and crumpling. Tectonic coal has the characteristics of low strength, high porosity and incomplete structure. A large amount of coal bed gas resources are stored in the constructed coal bed in China, and the constructed coal is a precious coal resource. Under the existing mining condition, because of the characteristics of constructional coal, the hand-twisting coal can be broken, no large block of formed coal sample exists, and the core-taking rate of drilling is low. The method for remodeling the structural coal sample is beneficial to improving the quantity of the sample and lays a foundation for further researching the mechanical properties of the structural coal in a laboratory.

The prior coal sample preparation methods mainly comprise a static pressure method and a drilling method. The static pressure method is mostly made by pressing coal particles or coal dust mixed cementing materials. Drilling core cutting on the large raw coal. The formation coal sample is obtained in a remodeling mode because the success rate of a drilling method is extremely low. At present, the static pressure method for preparing the multi-reference briquette for remolding structural coal samples is to adopt structural coal particles as aggregate, add an additive material and press the aggregate under certain pressure. Commonly used materials are gypsum, cement and sodium humate. Due to the characteristics of the properties, the structural and mechanical properties of the coal cannot be well reduced. Resulting in deviation of the test results from the actual situation.

Disclosure of Invention

Aiming at the defects of the technology, the remolded structural coal sample material and the sample preparation method are provided, wherein the method is simple, and the finished product effect is good.

In order to achieve the technical purpose, the remodeling construction coal sample formula comprises, by mass, 900 parts of construction coal powder with the particle size of less than 5mm, 100 parts of starch adhesive, 50-150 parts of water and 10-30 parts of alpha-amylase.

The preferable mixture ratio is 700 parts of tectonic coal powder with the grain diameter less than 5mm, 100 parts of starch adhesive, 80 parts of water and 16 parts of alpha-amylase.

A remolded tectorial coal sample formula comprises, by mass, 1000 parts of tectorial coal pulverized coal with the particle size of less than 5mm, 100 parts of soybean protein isolate adhesive, 80-165 parts of water and 16-33 parts of protease.

The preferable mixture ratio is 900 parts of tectonic coal powder with the grain diameter less than 5mm, 100 parts of soybean protein isolate adhesive, 100 parts of water and 20 parts of protease.

A preparation method for preparing a remolded tectonic coal sample comprises the following steps:

1) screening crushed coal powder with the particle size of less than 5mm as aggregate;

2) mixing the remolding structural coal sample formula materials according to the mass parts;

3) uniformly stirring after mixing until no lump with the diameter larger than 0.5cm exists, and stopping stirring to obtain a mixed material;

4) putting the mixed material into a columnar mold, putting the mold into a press machine for press molding, and setting molding pressure according to the density requirement, wherein the molding time is 30 min;

5) and (4) demolding after compression molding, and drying under natural conditions until the quality is not reduced any more to obtain the remolded structural coal sample.

Has the advantages that:

according to the remolding structural coal sample material formula, the natural cementing material is added, and the enzyme plant is used for removing, so that compared with the existing drilling method, the stability of the sample is effectively improved, and the damage rate of the sample in the test process is greatly reduced. The sample prepared by the formula simultaneously contains a large number of pore cracks, and the structural characteristics of the sample are reduced to the maximum extent.

The strength of the structural coal is low and not stable enough, the phenomena of cracking or slag stripping along the structural surface and the like often occur, in order to maintain the forming, a cementing material with high strength is added, so that the mechanical test effect is not ideal, the strength of the cementing material in the formula is weak, and the excessive filled cementing material is decomposed into small molecules under the action of an enzyme strain, so that the effect is gradually degraded and lost, the property of the structural coal is ideally restored, and the forming effect of a sample is maintained. The method solves the difficulty in the preparation process of the tectonic coal sample, provides an effective sample preparation method, and lays a foundation for further research on the mechanical properties of the tectonic coal in a laboratory.

Drawings

FIG. 1 is a schematic diagram of a mold structure for remodeling a constructed coal sample according to the present invention;

FIG. 2 is a plot of remodeling formation coal sample density and forming pressure in accordance with the present invention.

In the figure: 1-column pressure head, 2-side wall and 3-base.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings.

As shown in figure 1, the remolded structural coal sample is pressed by a grinding tool, and comprises a left side wall 2 and a right side wall 2, wherein a middle hollow part is reserved between the left side wall and the right side wall, a base 3 for plugging a hole below the side walls 2 is arranged at the bottom, a column pressing head 1 is arranged above the base, the two side walls 2 are fixedly connected through eight 10mm hexagonal screws, the base 3 and the side walls 2 are fixed through four 8mm hexagonal screws, a sample material is filled in the middle hollow part, and the column pressing head 1 is used for compacting and demoulding.

The remolded structural coal sample formula comprises, by mass, 900 parts of structural coal powder with the particle size of less than 5mm, 100 parts of starch adhesive, 50-150 parts of water and 10-30 parts of alpha-amylase; the preferable mixture ratio is as follows: 700 parts of tectonic coal powder with the grain diameter less than 5mm, 100 parts of starch adhesive, 80 parts of water and 16 parts of alpha-amylase.

A remolded tectorial coal sample formula comprises, by mass, 1000 parts of tectorial coal pulverized coal with the particle size of less than 5mm, 100 parts of soybean protein isolate adhesive, 80-165 parts of water and 16-33 parts of protease; 900 parts of tectonic coal powder with the particle size of less than 5mm, 100 parts of soybean protein isolate adhesive, 100 parts of water and 20 parts of protease.

The invention relates to a preparation method for preparing a remolded tectonic coal sample, which adopts two cementing materials, wherein one cementing material is starch glue, and the other cementing material is soybean protein isolate adhesive (hereinafter referred to as protein glue) which are respectively in different proportions.

The preparation method for preparing the remodeling structural coal sample by adopting the starch glue as the natural cementing material comprises the following steps:

preparing and selecting aggregate, cementing agent and additive, wherein the aggregate is coal powder with the particle size of less than 5 mm; the cementing agent is glutinous rice glue which takes starch as a main raw material; the additive comprises water and alpha-amylase, wherein the alpha-amylase is a commercial enzyme strain available on the market.

The specific formulation method of the present invention is thus achieved.

1) Screening coal powder for later use, and adjusting sufficient glutinous rice glue for later use.

2) Mixing the aggregate, the cementing agent, the additive water and the additive alpha-amylase according to the proportion of 7:1:0.8:0.16, dissolving the alpha-amylase in water, and then mixing.

3) Stirring uniformly, stopping stirring when no lump with diameter more than 0.5cm is generated.

4) The mixture is loaded into a mold, as shown in fig. 1, and is placed into a press for compression molding. The molding pressure was selected (for reference) according to fig. 2 and was selected by calculation with reference to the formula, with a molding time of 30 min.

5) And demolding and drying after pressing is finished.

The preparation method for preparing the remolded structural coal sample by adopting the albumin glue as the natural cementing material comprises the following steps:

preparing and selecting aggregate, cementing agent and additive, wherein the aggregate is coal powder with the particle size of less than 5 mm; the cementing agent is a soybean protein isolate adhesive which takes soybean protein isolate as a main raw material; the additive comprises water and neutral protease, and the neutral protease is a commercial enzyme strain available on the market.

1) Screening coal dust for later use; and preparing a sufficient amount of the protein gel for later use.

2) Mixing the aggregate, the cementing agent, the additive water and the additive protease according to the proportion of 9:1:1:0.2, dissolving the protease in water, and then mixing.

3) Stirring uniformly, and stopping stirring when no lump with diameter more than or equal to 0.5cm is generated.

4) The mixture is loaded into a mould (as shown in figure 1) and is put into a press for compression molding. The molding pressure is selected according to the density requirement, and the molding time is 30 min.

5) And demolding and drying after pressing is finished.

The drying process is also a bio-enzyme action phase during which the sample is kept as far as possible from moving and in a warm environment. After drying, the sample can be subjected to next experimental operation, and the physical and mechanical properties of the sample can be tested.

In order to ensure the forming of the sample in the preparation process, excessive cementing materials are added, and the cementing materials are filled in pores and cracks of the structural coal particles. The cementing material is natural high molecular polymer, the main component of the starch glue is natural starch, and alpha-amylase can hydrolyze alpha-1, 4 glycosidic bonds in the starch to change the starch into oligosaccharide or monosaccharide, so that the viscosity is rapidly reduced and the starch becomes liquefied starch. The protease can hydrolyze soybean protein isolate into small molecular peptides, thereby improving the solubility and reducing the viscosity. Under the enzymatic reaction, only a skeleton of the structural coal particles and a small amount of the cementing material are finally left, and the influence of the cementing material on the skeleton damage is negligible.

Example one

Firstly, pre-screening coal dust with the particle size of below 5mm, then weighing 210g of coal dust and 30g of glutinous rice glue, and uniformly stirring until no lump with the diameter of more than 0.5cm exists;

adding 24g of additive water and 4.8g of alpha-amylase into the mixture, adding the amylase into the water for melting, pouring the mixture into a stirring basin, and uniformly stirring until no lump with the diameter larger than 0.5cm exists;

and step three, filling the stirred mixture into a mold, and putting the mold into a press machine. Maintaining the pressure at 40MPa for 30 min;

step four, the sample is removed from the die and dried under natural conditions until the quality is not reduced;

and step five, testing the mechanical property.

Fig. 2 shows the density and forming pressure curves of the reshaped coal sample according to the present invention. And fitting a curve obtained by detecting the remolded structural coal sample with the sample data, wherein the curve can be referred to for calculating the molding pressure. Using fitting equations of curves as references

，r ² For correlation coefficients, closer to 1 indicates better fit.

Claims (5)

1. A remolded tectonic coal sample formula is characterized by comprising 900 parts of tectonic coal powder with the particle size of less than 5mm, 100 parts of starch adhesive, 50-150 parts of water and 10-30 parts of alpha-amylase by mass.

2. A remodeling conformation coal sample formula according to claim 1, wherein the preferable mixture ratio of the mass portions is: 700 parts of tectonic coal powder with the grain diameter less than 5mm, 100 parts of starch adhesive, 80 parts of water and 16 parts of alpha-amylase.

3. A remolded tectorial coal sample formula is characterized by comprising, by mass, 1000 parts of tectorial coal pulverized coal with the particle size of less than 5mm, 100 parts of soybean protein isolate adhesive, 80-165 parts of water and 16-33 parts of protease.

4. A remodeling conformation coal sample formula according to claim 2, wherein the preferable mixture ratio of the mass portions is: 900 parts of tectonic coal powder with the particle size of less than 5mm, 100 parts of soybean protein isolate adhesive, 100 parts of water and 20 parts of protease.

5. A method for preparing a remodeled tectonic coal sample according to claim 1 or 3, comprising the steps of:

1) screening crushed coal powder with the particle size of less than 5mm as aggregate;

2) mixing the remolding structural coal sample formula materials according to the mass parts;

3) uniformly stirring after mixing until no lump with the diameter larger than 0.5cm exists, and stopping stirring to obtain a mixed material;

4) putting the mixed material into a columnar mold, putting the mold into a press machine for press molding, and setting molding pressure according to the density requirement, wherein the molding time is 30 min;

5) and (4) demolding after compression molding, and drying under natural conditions until the quality is not reduced any more to obtain the remolded structural coal sample.

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