CN111829917A - Coal body adsorption desorption deformation anisotropy synchronous testing device and method - Google Patents
Coal body adsorption desorption deformation anisotropy synchronous testing device and method Download PDFInfo
- Publication number
- CN111829917A CN111829917A CN201910321083.7A CN201910321083A CN111829917A CN 111829917 A CN111829917 A CN 111829917A CN 201910321083 A CN201910321083 A CN 201910321083A CN 111829917 A CN111829917 A CN 111829917A
- Authority
- CN
- China
- Prior art keywords
- desorption
- adsorption
- coal
- deformation
- gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000003245 coal Substances 0.000 title claims abstract description 187
- 238000002336 sorption--desorption measurement Methods 0.000 title claims abstract description 53
- 238000012360 testing method Methods 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title claims abstract description 33
- 230000001360 synchronised effect Effects 0.000 title claims abstract description 24
- 238000003795 desorption Methods 0.000 claims abstract description 175
- 238000001179 sorption measurement Methods 0.000 claims abstract description 98
- 239000007789 gas Substances 0.000 claims abstract description 89
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 63
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 46
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 27
- 230000008569 process Effects 0.000 claims abstract description 25
- 239000001307 helium Substances 0.000 claims abstract description 17
- 229910052734 helium Inorganic materials 0.000 claims abstract description 17
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000003822 epoxy resin Substances 0.000 claims abstract description 12
- 229920000647 polyepoxide Polymers 0.000 claims abstract description 12
- 238000012545 processing Methods 0.000 claims abstract description 5
- 230000008859 change Effects 0.000 claims description 24
- 238000005520 cutting process Methods 0.000 claims description 12
- 239000003292 glue Substances 0.000 claims description 12
- 239000011148 porous material Substances 0.000 claims description 12
- 229910001873 dinitrogen Inorganic materials 0.000 claims description 10
- 229920001971 elastomer Polymers 0.000 claims description 9
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 6
- 238000001035 drying Methods 0.000 claims description 6
- 238000012544 monitoring process Methods 0.000 claims description 6
- 238000011084 recovery Methods 0.000 claims description 6
- 230000000087 stabilizing effect Effects 0.000 claims description 6
- 238000009792 diffusion process Methods 0.000 claims description 5
- 230000001276 controlling effect Effects 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 239000010949 copper Substances 0.000 claims description 4
- 230000001186 cumulative effect Effects 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 3
- 244000137852 Petrea volubilis Species 0.000 claims description 3
- 238000013459 approach Methods 0.000 claims description 3
- 230000005540 biological transmission Effects 0.000 claims description 3
- 230000006835 compression Effects 0.000 claims description 3
- 238000007906 compression Methods 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 3
- 230000002596 correlated effect Effects 0.000 claims description 3
- 230000000875 corresponding effect Effects 0.000 claims description 3
- 230000000149 penetrating effect Effects 0.000 claims description 3
- 238000005498 polishing Methods 0.000 claims description 3
- 238000005086 pumping Methods 0.000 claims description 3
- 238000007789 sealing Methods 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 239000002344 surface layer Substances 0.000 claims description 3
- BFKJFAAPBSQJPD-UHFFFAOYSA-N tetrafluoroethene Chemical group FC(F)=C(F)F BFKJFAAPBSQJPD-UHFFFAOYSA-N 0.000 claims description 3
- 238000005259 measurement Methods 0.000 abstract description 6
- 239000000853 adhesive Substances 0.000 abstract description 5
- 230000001070 adhesive effect Effects 0.000 abstract description 5
- 238000011160 research Methods 0.000 description 6
- 210000003437 trachea Anatomy 0.000 description 6
- 239000000463 material Substances 0.000 description 4
- 238000005065 mining Methods 0.000 description 4
- 238000000605 extraction Methods 0.000 description 3
- 230000035699 permeability Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000010292 electrical insulation Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000011435 rock Substances 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 229920001187 thermosetting polymer Polymers 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 239000003984 copper intrauterine device Substances 0.000 description 1
- 230000001808 coupling effect Effects 0.000 description 1
- 238000013500 data storage Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000010902 straw Substances 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N7/00—Analysing materials by measuring the pressure or volume of a gas or vapour
- G01N7/02—Analysing materials by measuring the pressure or volume of a gas or vapour by absorption, adsorption, or combustion of components and measurement of the change in pressure or volume of the remainder
- G01N7/04—Analysing materials by measuring the pressure or volume of a gas or vapour by absorption, adsorption, or combustion of components and measurement of the change in pressure or volume of the remainder by absorption or adsorption alone
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/16—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge
- G01B7/18—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring the deformation in a solid, e.g. by resistance strain gauge using change in resistance
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N7/00—Analysing materials by measuring the pressure or volume of a gas or vapour
- G01N7/14—Analysing materials by measuring the pressure or volume of a gas or vapour by allowing the material to emit a gas or vapour, e.g. water vapour, and measuring a pressure or volume difference
- G01N7/16—Analysing materials by measuring the pressure or volume of a gas or vapour by allowing the material to emit a gas or vapour, e.g. water vapour, and measuring a pressure or volume difference by heating the material
Landscapes
- Chemical & Material Sciences (AREA)
- General Physics & Mathematics (AREA)
- Physics & Mathematics (AREA)
- Biochemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
A synchronous testing device and method for anisotropy of coal adsorption desorption deformation is characterized in that on the basis of experimental study on coal adsorption desorption deformation by the existing method, an experimental device consisting of a nitrogen cylinder, a helium cylinder, an electromagnetic valve, a pressure sensor, a vacuum pump, a vacuum gauge, a constant temperature water bath tank, an adsorption desorption and desorption tank, a desorption and gas collection device, a resistance strain gauge, a strain gauge and a computer is adopted, an experimental coal sample is placed into the adsorption and desorption tank, different pressure and temperature conditions are controlled by the electromagnetic valve, the pressure sensor and the constant temperature water bath tank, a sealed environment is ensured by epoxy resin adhesive, anisotropy measurement is carried out on the desorption deformation of the coal under different conditions by using a strain data acquisition system, the experimental result is automatically recorded by a data processing system, the operation process is labor-saving and labor-saving, no redundant pipeline connection exists, and the loss of excessive gas in a pipeline is avoided, the method can be suitable for real-time synchronous measurement of the stress strain of the coal body under different air pressures and different temperatures.
Description
Technical Field
The invention belongs to the technical field of coal body deformation strain testing, and particularly relates to a synchronous testing device and method for coal body adsorption desorption deformation anisotropy.
Background
Most coal bed gas reservoirs in mining areas in China have the typical characteristics of low pressure, low permeability, low saturation and strong heterogeneity, namely three-low-one-strong, the difficulty of direct mining is high, many mines begin to be mined towards the deep part gradually along with continuous mining of coal resources, the coal bed gas pressure is increased along with the deepening of mining depth, and the ground stress is increased, so that the coal bed with low gas content has the possibility of gas outburst danger. The expansion deformation value of the coal body absorbing gas is influenced by multiple factors, and under the same gas pressure, the difference of the absorption expansion deformation values of the outburst coal and the non-outburst coal is large. Therefore, the swelling deformation value of the coal body can be used as an important index when identifying whether the coal seam has a projecting risk.
The method has a promoting effect on the development of the gas extraction technology. Among the engineering and scientific problems of gas drainage, the coupling effect between the adsorption and desorption deformation of coal and the gas flow is the most difficult problem to solve. In the process of gas permeation and diffusion, the pressure, concentration and composition of gas in an unbalanced state are constantly changed, so that coal bodies are expanded or contracted to deform, and the change of the volume of the coal bodies causes the change of porosity, thereby changing the permeability of the coal bodies. The change in permeability coefficient of coal in turn affects the seepage and diffusion of gas in the coal. Therefore, the influence of coal adsorption/desorption deformation cannot be ignored when understanding the real migration rule of coal in the coal seam. The research on the adsorption/desorption deformation rule of the coal body has an important guiding function on the prevention and treatment of coal and gas outburst, and is also a basic research on the extraction of coal bed gas.
In summary, the previous research results are mostly focused on the research on the coal body adsorption expansion deformation rule, the research on desorption contraction deformation is relatively less, the research on the deformation rule in two directions of vertical bedding and parallel bedding is mostly surrounded on the aspect of deformation anisotropy characteristics, and because the parallel bedding direction surface cleat and end cleat development degree, connectivity and fracture opening degree are different in the coal bed, obvious anisotropy still exists in the parallel bedding direction. Therefore, the anisotropic characteristic of coal rock adsorption and desorption deformation remains to be further researched.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a synchronous testing device and method for coal body adsorption desorption deformation anisotropy, which can measure the stress strain of a coal body under the conditions of different air pressures and different temperatures in real time, have a simple structure, are simple, convenient and direct to operate, automatically record the test result by a data processing system, and save trouble and labor in the operation process.
In order to solve the technical problems, the invention adopts the following technical scheme.
Preferably, the coal body adsorption desorption deformation anisotropy synchronous testing device comprises an adsorption/desorption system, a data acquisition system, a gas source system, a vacuum system, a pressure stabilizing system and a temperature control system; the air source system is connected with the adsorption/desorption system, the adsorption/desorption system is arranged in the temperature control system, the vacuum system is connected with the adsorption/desorption system through a vacuum tube, the pressure stabilizing system comprises an electromagnetic valve and a pressure sensor, the electromagnetic valve is arranged between the air source system and the adsorption/desorption system, the pressure sensor is arranged in the adsorption/desorption system, and the data acquisition system is respectively connected with the electromagnetic valve and the pressure sensor through data lines.
Preferably, the data acquisition system includes resistance strain gauge, strain gauge and computer, and the computer passes through the data line and is connected with the strain gauge, and resistance strain gauge is provided with three, and three resistance strain gauge is connected with the strain gauge through an enameled copper line respectively.
Preferably, the adsorption/desorption system comprises an adsorption and desorption tank, a top cover is arranged at the top of the adsorption and desorption tank, the top cover and the adsorption and desorption tank body are sealed by a flat gasket made of tetrafluoroethylene material, and the top cover and the outer circumference of the adsorption and desorption tank are tightly buckled into a whole through a U-shaped buckle; in order to realize the transmission of strain data, a threading pipe and a vent pipe are arranged on the top cover, a first pressure gauge positioned above the top cover is arranged on the vent pipe, three enameled copper wires penetrate through the threading pipe, three resistance strain gauges are arranged in an adsorption and desorption tank, in order to ensure the air tightness, the threading pipe is encapsulated by epoxy resin glue, and the applicable temperature of the epoxy resin glue is between-50 ℃ and +150 ℃; the pressure sensor is arranged on the inner side of the adsorption desorption tank and is connected with the computer through a first signal wire penetrating through the top cover.
Preferably, the air supply system includes nitrogen cylinder and helium bottle, and the helium bottle is connected with the breather pipe through first trachea, has set gradually first valve, second manometer along the air current direction on the first trachea and solenoid valve, the solenoid valve passes through the second signal line and is connected with the computer, the nitrogen cylinder passes through the second trachea and connects on the first trachea between second manometer and the solenoid valve, is provided with the second valve on the second trachea.
Preferably, the temperature control system comprises a constant temperature water bath box, and the adsorption and desorption tank is arranged in the constant temperature water bath box.
Preferably, the device also comprises a desorption gas-collecting device which comprises six desorption burettes and a water containing tank; six desorption measuring tubes are arranged side by side, are inserted below the water surface in the water containing tank with the openings facing downwards, are connected in series through rubber tubes at the tops, each rubber tube is clamped with a clamp, the lower end opening of one desorption measuring tube is connected with a vent pipe through a desorption tube, and a third valve is arranged on the desorption tube.
Preferably, the vacuum system comprises a rotary vane type vacuum pump, the rotary vane type vacuum pump is connected with the vent pipe through a vacuum pipe, a fourth valve is arranged on the vacuum pipe, and a vacuum gauge is connected to the rotary vane type vacuum pump.
The testing method of the coal body adsorption desorption deformation anisotropy synchronous testing device comprises the following steps:
step one, preparing a coal sample;
bonding the three resistance strain gauges to the surface of the coal sample, arranging a support at the bottom in the adsorption and desorption tank, placing the coal sample on the support, closing the top cover, and fastening the U-shaped buckle to seal the top cover and the adsorption and desorption tank;
step three, detecting the air tightness of the adsorption and desorption tank and the connected pipeline: closing the second valve, the third valve and the fourth valve, opening the first valve and the electromagnetic valve, filling helium with 1MPa into the adsorption and desorption tank by helium gas in the helium tank through the first air pipe and the vent pipe to detect air tightness, keeping the pressure of 1MPa for 12 hours, checking the first pressure gauge and the second pressure gauge every 2 hours, and if the effective readings are all 1MPa, proving that the air tightness of the adsorption and desorption tank and the connected pipelines is good;
step four, putting the adsorption and desorption tank into a constant-temperature water bath box for heating;
step five, vacuumizing the adsorption and desorption tank: closing the first valve, the electromagnetic valve, the second valve and the third valve, opening the fourth valve, starting the rotary vane vacuum pump to continuously vacuumize the adsorption and desorption tank through the vacuum tube and the vent pipe, closing the fourth valve after continuously vacuumizing for 2 hours when 0.1MPa negative pressure is formed, stopping vacuumizing, and starting the strain gauge to record the change of the strain number value every 1s in the vacuumizing stage;
opening a second valve and an electromagnetic valve, filling nitrogen into the adsorption and desorption tank by the nitrogen in a nitrogen bottle, enabling the nitrogen in the adsorption and desorption tank to reach a preset gas pressure, displaying the reflection condition of the pressure in the adsorption and desorption tank on a computer through a pressure sensor, and controlling and adjusting the electromagnetic valve, so that the gas pressure in the adsorption and desorption tank is in a stable pressure state, the coal sample is subjected to adsorption expansion deformation, recording the value change acquired by a resistance strain gauge every 1s, and considering that the coal sample reaches adsorption balance until the data acquired by the strain gauge is unchanged, namely when a strain curve on the computer is approximate to a horizontal straight line;
step seven, after the coal sample reaches the adsorption balance, quickly closing the second valve and the electromagnetic valve, simultaneously opening the third valve, enabling nitrogen in the adsorption and desorption tank to enter the desorption measuring pipe through the vent pipe and the desorption pipe, and continuously monitoring the resistance strain gauge monitoring adhered to the coal sample through the strain gaugeThe measured value changes, and the rate of change of the strain to be measured is less than 2 multiplied by 10-4h-1When the coal desorption and gas collection device is used, the desorption balance can be considered to be achieved, meanwhile, the monitoring desorption and gas collection device displays the numerical value change condition of the gas desorption amount, the desorption deformation amount and the accumulated desorption amount are correlated and compared, and the coal desorption deformation condition is comprehensively reflected;
and step eight, repeating the step five to the step seven, changing the set value of the gas pressure in the adsorption and desorption tank, and measuring the adsorption-desorption strain of the coal sample under different pressure conditions.
The specific processes of the first step and the second step are as follows:
according to a coal object to be researched, a corresponding coal sample is taken, the size of a coal block is measured by using a ruler, a cutting route is divided by using a color pen, and in order to meet the requirement that the adsorption and desorption deformation rules of the coal layer in three directions under different gas pressures can be simultaneously tested at one time, a cubic block sample is selected for testing the adsorption expansion deformation anisotropy; cutting and processing a coal block into a cube coal sample with the side length of 60mm, wiping the surface of the coal sample with alcohol before the coal sample is tested, slightly polishing the surface with sand paper to be smooth, then drying the coal sample in a drying oven at 100 ℃ for 48h, cooling, and sealing and storing the coal sample with a freshness protection package for later use; selecting places without obvious cracks on the surface on three sides of the coal sample, and respectively sticking the three resistance strain gauges on the three sides by glue.
In the fifth step, the coal body sample is subjected to shrinkage deformation in the vacuumizing stage, after half an hour, the shrinkage deformation of the coal body sample tends to be balanced, and at the moment, air and moisture in the coal body sample are exhausted; the difference of the strain between the vertical bedding direction and the vertical surface cleat direction is small, and the difference of the strain between the vertical bedding direction and the vertical surface cleat direction is large; the deformation of the coal sample cracks plays a main control role in the vacuum pumping process, and gas is mainly gathered in large pores and cracks;
in the sixth step, after nitrogen with certain pressure is filled in the adsorption and desorption tank, larger confining pressure can be generated around the coal sample instantly, as the coal sample is placed on the bracket, six surfaces of the coal sample can be subjected to the confining pressure, the adsorption and expansion deformation of the coal sample is ignored at the moment and mainly expressed as compression deformation, after the nitrogen in the adsorption and desorption tank reaches the preset pressure, the nitrogen gas rapidly enters cracks and pores in the coal sample and is subjected to seepage and diffusion, the adsorption gas enables the micro-pores and micro-cracks of the coal sample to be reduced in surface energy, the thickness of a surface layer is increased, and free gas enables the volumes of the micro-pores and the micro-cracks to be increased, so that the coal sample is subjected to expansion deformation;
in the seventh step, the coal sample is not simply shrunk and deformed all the time in the nitrogen desorption process, and an instant expansion deformation process can occur when high-pressure gas is rapidly discharged; the deformation in the vertical bedding direction is large, the deformation in the parallel bedding vertical plane in the cutting direction is small, and the cutting direction of the vertical end of the parallel bedding has no obvious change; starting an elastic recovery deformation stage along with the expansion deformation of the coal sample, wherein the elastic recovery deformation stage has extremely short duration and large deformation; in the desorption shrinkage deformation stage of the coal sample, along with the continuous increase of desorption time, the slope of a shrinkage deformation curve is gradually reduced until the slope approaches to 0 finally, the relative shrinkage deformation of the coal sample is continuously increased, and finally an approximate stable value is reached;
in addition, in the seventh step, the coal sample is subjected to volume strain in the nitrogen desorption process v Defined as the amount of change in unit volume of the object, the magnitude is expressed as:
wherein the content of the first and second substances,1、 2 、 3 respectively expressed as vertical bedding strain, parallel bedding vertical plane cleaving strain and parallel bedding vertical end cleaving strain. In addition, the cumulative amount of desorption of the coalQ t At the time of desorptiontThe size of the coal body desorption gas. In the coal body desorption deformation process, in the initial desorption stage, the coal body desorption gas speed is higher than the coal body deformation speed, and then the coal body deformation speed is gradually higher than the desorption gas speed. Overall, the volume strain and the gas desorption cumulant have better positive correlation.
By adopting the technical scheme, the invention has the following technical effects.
1. The epoxy resin glue is used for encapsulating the threading tube, the applicable temperature of the epoxy resin glue is generally-50 to +150 ℃, and the epoxy resin glue has the characteristics of compactness, water resistance, good leakage resistance, high strength, good electrical insulation performance, bonding performance with various materials, flexibility of the use process, and the like which are not possessed by other thermosetting plastics, and has good manufacturability such as strong adhesive force, normal-temperature operation, simple and convenient construction, and moderate cost.
2. The strain gauge can measure three physical quantities of strain, tension and pressure and displacement at the same time, and has the functions of peak value measurement, data storage, data playback and the like. The instrument has 4 channels, namely, the instrument can support 4 strain gauges to monitor simultaneously at most, and the measuring range is +/-38000μThe measurement precision is 0.1 percent, and the time zero drift is less than or equal to 3μA temperature drift of less than or equal to 1 hμ/℃。
3. The constant temperature water bath tank is always in a working state no matter in the vacuumizing process or the adsorption and desorption process. The adsorption and desorption tank is completely immersed in the super constant temperature water bath except for the pressure gauge above the top cover. If the water in the constant temperature water bath box is evaporated, water should be supplemented in time to ensure sufficient water quantity. The constant temperature water bath box is composed of HH-601 model super constant temperature water bath pot manufactured by Changzhou Jintanjinda instruments manufacturing company. The internal high-quality water pump ensures that the set water temperature in the experiment is uniform and constant, and meets the experiment requirements. The important performance parameters of the super constant-temperature water bath are as follows, and the size of the working tank is as follows: 400mm 300mm 200 mm; temperature control range: room temperature-99.9 ℃; constant temperature setting and measurement: LED digital display; circulating speed of the water pump: not less than 4L/min, temperature floating range: less than or equal to 0.1 ℃. The temperature in the adsorption and desorption tank in the water bath is changed by controlling the water temperature through the constant-temperature circulating water bath, so that the purpose of measuring the deformation condition of the coal sample at different temperatures is achieved.
4. The vacuum pump adopts a series of 2XZ type rotary vane vacuum pumps with a double-stage direct connection structure, and the pump has a plurality of characteristics, such as: high rotating speed, small size, compact structure, fluidity, convenient work and the like. The 2XZ vacuum pump is mainly composed of 11 parts, such as an air inlet nozzle, a rotary vane, a rotor, an oil tank and the like. The vacuum pump has the following performance parameters: intake bore d (mm): 16; motor power p (kw): 0.25; limiting pressure is less than or equal to (Pa): 6X 10-2; rotational speed (rpm): 1440; air extraction rate (L/S): 1. the vacuum gauge is a ZDZ-52 type vacuum gauge with strong anti-interference capability, fast reaction and long service life. It is suitable for measuring low and medium vacuums. The performance parameters are as follows: point control or area control; the display mode is as follows: digital display (single display); power supply: AC220V + -10% 50 Hz; the use environment is as follows: -5-40 ℃ and humidity less than or equal to 95 percent; measurement control range: 1.0X 10-1Pa to 1.0X 105 Pa; response time: less than or equal to 1 s; and (3) control precision: plus or minus 1 percent.
5. The desorption gas-collecting device is characterized in that a water containing tank is filled with saturated salt water, and the saturated salt water in the water tank is firstly sucked to a set position in a burette through an air suction tube. In general, the initial liquid level in the desorption amount tube was 0 scale mark. The connection between the large measuring tube and the small measuring tube is switched, the uppermost ends of the measuring tubes are communicated by using rubber tubes, and the rubber tubes are clamped by using clamps to stop the rubber tubes. During desorption, when the liquid level in the first large number of tubes is lowered to the lowest level, the clamp is released to rapidly switch the desorbed gas to the second large number of tubes, and so on. According to experience, if the desorption amount of the prepared coal sample is not large, a small pipe can be directly connected for desorption. The large tube range is 800ml, the small tube range is 200ml, and the minimum scales are 4ml and 2ml respectively.
In summary, the present invention has the following advantages.
1. The coal deformation anisotropy synchronous testing device can be used for testing the deformation of the coal in the whole adsorption and desorption process in three directions under different conditions (different air pressures and different temperatures), and can also be used for testing the deformation conditions of other rock test pieces.
2. The adsorption and desorption tank is internally provided with a pressure sensor which is connected with a computer and controls the flow of the electromagnetic valve according to pressure data, so that the gas condition in the tank is ensured to reach a stable state, and the influence of external gas pressure on the adsorption and desorption deformation of the coal body is eliminated.
3. The epoxy resin adhesive is adopted for encapsulation, the applicable temperature is generally between-50 and +150 ℃, and the epoxy resin adhesive has the characteristics of compactness, water resistance, good leakage resistance, high strength, good electrical insulation performance, bonding performance with various materials, flexibility of the use process, and the like which are not possessed by other thermosetting plastics, and has good manufacturability such as strong adhesive force, normal-temperature operation, simple and convenient construction, and moderate price.
4. The data acquisition system in the coal body deformation anisotropy synchronous testing device can directly display the actual deformation and strain conditions of the coal body sample on a display of a computer through signal conversion, so that the testing result is more accurate and reliable; the circulating water bath function of the constant temperature water bath box improves the condition of a wave line caused by nonuniform heating of water in the constant temperature water bath box, and can meet the requirement of a test on temperature control.
Drawings
FIG. 1 is a schematic view of the overall structure of the present invention;
FIG. 2 is a schematic longitudinal cross-sectional view of the adsorption and desorption tank of FIG. 1;
FIG. 3 is a graph of strain during evacuation plotted using strain data;
FIG. 4 is a graph of adsorption phase strain plotted using strain data;
FIG. 5 is a graph of desorption phase strain plotted using strain data;
FIG. 6 is a graph plotting volumetric strain during desorption versus cumulative desorption using strain data versus desorption data.
The technical characteristics of each number in the figure are as follows:
1-vacuum tube; 2-an electromagnetic valve; 3-a pressure sensor; 4-resistance strain gauge; 5-a strain gauge; 6-a computer; 7-enameled copper wire; 8-adsorbing and desorbing the tank; 9-a top cover; 10-U-shaped buckle; 11-a threading tube; 12-a breather pipe; 13-a first pressure gauge; 14-nitrogen gas cylinder; 15-helium tank; 16-a first air tube; 17-a first valve; 18-a second pressure gauge; 19-a first signal line; 20-a second signal line; 21-a second valve; 22-constant temperature water bath tank; 23-desorption gas-collection device; 24-relieving the straw; 25-a third valve; 26-rotary vane vacuum pump; 27-a fourth valve; 28-vacuum gauge; 29-coal sample; 30-a scaffold; 31-second trachea.
Detailed Description
As shown in fig. 1 and 2, the coal body adsorption/desorption deformation anisotropy synchronous testing device of the invention comprises an adsorption/desorption system, a data acquisition system, an air source system, a vacuum system, a pressure stabilizing system and a temperature control system;
the gas source system is connected with the adsorption/desorption system, the adsorption/desorption system is arranged in the temperature control system, the vacuum system is connected with the adsorption/desorption system through a vacuum tube 1, the pressure stabilizing system comprises an electromagnetic valve 2 and a pressure sensor 3, the electromagnetic valve 2 is arranged between the gas source system and the adsorption/desorption system, the pressure sensor 3 is arranged in the adsorption/desorption system, and the data acquisition system is respectively connected with the electromagnetic valve 2 and the pressure sensor 3 through data lines.
The data acquisition system includes resistance strain gauge 4, strain gauge 5 and computer 6, and computer 6 passes through the data line and is connected with strain gauge 5, and resistance strain gauge 4 is provided with threely, and three resistance strain gauge 4 is connected with strain gauge 5 through an enameled copper 7 respectively.
The adsorption/desorption system comprises an adsorption and desorption tank 8, a top cover 9 is arranged at the top of the adsorption and desorption tank 8, the top cover 9 and the adsorption and desorption tank 8 are sealed by a flat gasket made of tetrafluoroethylene, and the top cover 9 and the outer circumference of the adsorption and desorption tank 8 are tightly buckled into a whole through a U-shaped buckle 10; in order to realize the transmission of strain data, a threading pipe 11 and a vent pipe 12 are arranged on a top cover 9, a first pressure gauge 13 positioned above the top cover 9 is arranged on the vent pipe 12, three enameled copper wires 7 penetrate through the threading pipe 11, three resistance strain gauges 4 are arranged in an adsorption desorption tank 8, and in order to ensure the air tightness, the threading pipe 11 is encapsulated by epoxy resin glue, and the applicable temperature of the epoxy resin glue is between-50 ℃ and +150 ℃; the pressure sensor 3 is arranged at the inner side part of the adsorption and desorption tank 8, and the pressure sensor 3 is connected with the computer 6 through a first signal wire 19 penetrating through the top cover 9.
The gas source system comprises a nitrogen gas bottle 14 and a helium gas bottle 15, the helium gas bottle 15 is connected with a vent pipe 12 through a first gas pipe 16, a first valve 17, a second pressure gauge 18 and an electromagnetic valve 2 are sequentially arranged on the first gas pipe 16 along the airflow direction, the electromagnetic valve 2 is connected with a computer 6 through a second signal line 20, the nitrogen gas bottle 14 is connected with the first gas pipe 16 between the second pressure gauge 18 and the electromagnetic valve 2 through a second gas pipe 31, and a second valve 21 is arranged on the second gas pipe 31.
The temperature control system comprises a constant temperature water bath box 22, and the adsorption and desorption tank 8 is arranged in the constant temperature water bath box 22.
The invention also comprises a desorption gas-collecting device 23, wherein the desorption gas-collecting device 23 comprises six desorption measuring tubes and a water containing tank; six desorption measuring tubes are arranged side by side and are inserted below the water surface in the water containing tank with the openings facing downwards, the tops of the six desorption measuring tubes are connected in series through rubber tubes, each rubber tube is clamped with a clamp (not shown in the figure), the lower end opening of one desorption measuring tube is connected with the vent pipe 12 through a desorption pipe 24, and the desorption pipe 24 is provided with a third valve 25.
The vacuum system comprises a rotary vane type vacuum pump 26, the rotary vane type vacuum pump 26 is connected with the vent pipe 12 through the vacuum pipe 1, the vacuum pipe 1 is provided with a fourth valve 27, and the rotary vane type vacuum pump 26 is connected with a vacuum gauge 28.
The specific experimental process of the coal body adsorption desorption deformation anisotropy synchronous testing device is as follows:
step one, preparing a coal sample 29;
bonding the three resistance strain gauges 4 to the surface of a coal sample 29, arranging a support 30 at the bottom in the adsorption and desorption tank 8, placing the coal sample 29 on the support 30, closing a top cover 9, and fastening a U-shaped buckle 10 to seal the top cover 9 and the adsorption and desorption tank 8;
step three, detecting the air tightness of the adsorption and desorption tank 8 and the connected pipelines: closing the second valve 21, the third valve 25 and the fourth valve 27, opening the first valve 17 and the electromagnetic valve 2, filling helium of 1MPa into the adsorption and desorption tank 8 by the helium gas in the helium tank 15 through the first air pipe 16 and the vent pipe 12 to detect the air tightness, keeping the pressure of 1MPa for 12h, checking the first pressure gauge 13 and the second pressure gauge 18 every 2 hours, and if the effective readings are all 1MPa, proving that the air tightness of the adsorption and desorption tank 8 and the connected pipelines is good;
step four, the adsorption and desorption tank 8 is placed in a constant-temperature water bath box 22 for heating;
step five, vacuumizing the adsorption and desorption tank 8: closing the first valve 17, the electromagnetic valve 2, the second valve 21 and the third valve 25, opening the fourth valve 27, starting the rotary vane vacuum pump to continuously vacuumize the adsorption desorption tank 8 through the vacuum tube 1 and the vent tube 12, closing the fourth valve 27 after continuously vacuuming for 2 hours when negative pressure of 0.1MPa is formed, stopping vacuuming, and recording the change of the strain number every 1s by the strain gauge 5 in the vacuumizing stage;
step six, opening a second valve 21 and an electromagnetic valve 2, filling nitrogen into an adsorption and desorption tank 8 by the nitrogen in a nitrogen bottle 14, enabling the nitrogen in the adsorption and desorption tank 8 to reach a preset gas pressure, displaying the reflection condition of the gas pressure in the adsorption and desorption tank 8 on a computer 6 through a pressure sensor 3, and controlling and adjusting the electromagnetic valve 2, so that the gas pressure in the adsorption and desorption tank 8 is in a stable pressure state, a coal sample 29 is subjected to adsorption expansion deformation, recording the value change acquired by a resistance strain gauge 4 every 1s, and considering that the coal sample 29 reaches adsorption balance until the data acquired by a strain gauge 5 is unchanged, namely when a strain curve on the computer 6 is approximate to a horizontal straight line;
step seven, after the coal sample 29 reaches the adsorption equilibrium, rapidly closing the second valve 21 and the electromagnetic valve 2, simultaneously opening the third valve 25, enabling the nitrogen in the adsorption and desorption tank 8 to enter the desorption amount pipe through the vent pipe 12 and the desorption pipe 24, continuously monitoring the numerical value change of the resistance strain gauge 4 adhered to the coal sample 29 through the strain gauge 5, and waiting the strain change rate to be less than 2 multiplied by 10- 4h-1When the coal desorption and gas collection device is used, the desorption balance can be considered to be achieved, meanwhile, the monitoring desorption and gas collection device displays the numerical value change condition of the gas desorption amount, the desorption deformation amount and the accumulated desorption amount are correlated and compared, and the coal desorption deformation condition is comprehensively reflected;
and step eight, repeating the step five to the step seven, changing the set value of the gas pressure in the adsorption and desorption tank 8, and measuring the adsorption-desorption strain of the coal sample 29 under different pressure conditions.
The specific processes of the first step and the second step are as follows:
according to the coal object to be researched, a corresponding coal sample 29 is taken, the size of the coal block is measured by using a ruler, and a cutting route is divided by using a color pen, so that the adsorption and desorption deformation rule of the coal layer in three directions under different gas pressures can be simultaneously tested at one time, and therefore, a cubic block sample is selected for testing the adsorption expansion deformation anisotropy; cutting and processing the coal blocks into cubic coal samples 29 with the side length of 60mm, wiping the surfaces of the coal samples 29 with alcohol before the coal samples 29 are tested, slightly polishing the surfaces with sand paper, then drying the surfaces in a drying oven at 100 ℃ for 48h, cooling and sealing the surfaces with a freshness protection package for later use; three resistance strain gauges 4 are respectively adhered to three sides of a coal sample 29 by glue at positions where no obvious cracks exist on the surface.
As shown in fig. 3, in the fifth step, the coal sample 29 undergoes shrinkage deformation during the vacuum-pumping stage, and after half an hour, the shrinkage deformation of the coal sample 29 tends to be balanced, and at this time, the air and the moisture in the coal sample 29 are exhausted; the difference of the strain between the vertical bedding direction and the vertical surface cleat direction is small, and the difference of the strain between the vertical bedding direction and the vertical surface cleat direction is large; indicating that the fracture deformation of the coal sample 29 during the evacuation process plays a dominant role and that gas is mainly accumulated in large pores and fractures.
As shown in fig. 4, in the sixth step, after the adsorption and desorption tank 8 is filled with nitrogen gas under a certain pressure, a large confining pressure is instantaneously generated around the coal sample 29, since the coal sample 29 is placed on the support 30, six surfaces of the coal sample 29 can be subjected to confining pressure, the adsorption and expansion deformation of the coal sample 29 is negligible, and mainly expressed as compression deformation, after the nitrogen gas in the adsorption and desorption tank 8 reaches a predetermined pressure, the nitrogen gas rapidly enters cracks and pores in the coal sample 29 and is subjected to seepage and diffusion, the adsorption gas reduces the surface energy of the micro-pores and micro-cracks of the coal sample 29, the thickness of the surface layer is increased, and the free gas promotes the increase of the volumes of the micro-pores and the micro-cracks, so that the coal sample 29 is subjected to expansion deformation.
As shown in fig. 5, in the seventh step, the coal sample 29 is not simply shrunk and deformed all the time during the desorption of the nitrogen, and a transient expansion and deformation process occurs during the rapid discharge of the high-pressure gas; the deformation in the vertical bedding direction is large, the deformation in the parallel bedding vertical plane in the cutting direction is small, and the cutting direction of the vertical end of the parallel bedding has no obvious change; after the coal sample 29 expands and deforms, an elastic recovery deformation stage begins, wherein the duration of the elastic recovery deformation stage is extremely short, and the deformation amount is large; in the desorption shrinkage deformation stage of the coal sample 29, along with the continuous increase of the desorption time, the slope of the shrinkage deformation curve is gradually reduced until the slope finally approaches to 0, and the relative shrinkage deformation of the coal sample 29 is continuously increased and finally reaches an approximate stable value.
As shown in FIG. 6, in step seven, a coal sample 29 is obtained v The volume strain is defined as the amount of change per unit volume of the object, and the magnitude is expressed by the following equation:
wherein the content of the first and second substances,1、 2 、 3 respectively expressed as vertical bedding strain, parallel bedding vertical plane cleaving strain and parallel bedding vertical end cleaving strain. In addition, the cumulative amount of desorption of the coalQ t At the time of desorptiontThe size of the coal body desorption gas. It can be seen that, in the coal body desorption deformation process, at the initial stage of desorption, the coal body desorption gas speed is faster than the coal body deformation speed, and then, the coal body deformation speed is gradually faster than the desorption gas speed. Overall, the volume strain and the gas desorption cumulant have better positive correlation.
In the case of the figures 3-5,1、 2 、 3 respectively expressed as vertical bedding strain, parallel bedding vertical plane cleaving strain and parallel bedding vertical end cleaving strain; in the context of figure 6, it is shown, v 、Q t respectively representing the volume strain and the accumulated desorption amount of the coal sample.
The present embodiment is not intended to limit the shape, material, structure, etc. of the present invention in any way, and any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.
Claims (10)
1. The synchronous testing device for coal body adsorption desorption deformation anisotropy is characterized in that: comprises an adsorption/desorption system, a data acquisition system, a gas source system, a vacuum system, a pressure stabilizing system and a temperature control system; the air source system is connected with the adsorption/desorption system, the adsorption/desorption system is arranged in the temperature control system, the vacuum system is connected with the adsorption/desorption system through a vacuum tube, the pressure stabilizing system comprises an electromagnetic valve and a pressure sensor, the electromagnetic valve is arranged between the air source system and the adsorption/desorption system, the pressure sensor is arranged in the adsorption/desorption system, and the data acquisition system is respectively connected with the electromagnetic valve and the pressure sensor through data lines.
2. The coal body adsorption desorption deformation anisotropy synchronous testing device according to claim 1, characterized in that: the data acquisition system comprises three resistance strain gauges, three strain gauges and a computer, wherein the computer is connected with the strain gauges through data lines, and the three resistance strain gauges are respectively connected with the strain gauges through an enameled copper wire.
3. The coal body adsorption desorption deformation anisotropy synchronous testing device according to claim 2, characterized in that: the adsorption/desorption system comprises an adsorption and desorption tank, a top cover is arranged on the top of the adsorption and desorption tank, the top cover and the adsorption and desorption tank body are sealed by a flat gasket made of tetrafluoroethylene, and the top cover and the outer circumference of the adsorption and desorption tank are tightly buckled into a whole through a U-shaped buckle; in order to realize the transmission of strain data, a threading pipe and a vent pipe are arranged on the top cover, a first pressure gauge positioned above the top cover is arranged on the vent pipe, three enameled copper wires penetrate through the threading pipe, three resistance strain gauges are arranged in an adsorption and desorption tank, in order to ensure the air tightness, the threading pipe is encapsulated by epoxy resin glue, and the applicable temperature of the epoxy resin glue is between-50 ℃ and +150 ℃; the pressure sensor is arranged on the inner side of the adsorption desorption tank and is connected with the computer through a first signal wire penetrating through the top cover.
4. The coal body adsorption desorption deformation anisotropy synchronous testing device according to claim 3, characterized in that: the gas source system comprises a nitrogen gas bottle and a helium gas bottle, the helium gas bottle is connected with the vent pipe through a first gas pipe, a first valve, a second pressure gauge and an electromagnetic valve are sequentially arranged on the first gas pipe along the air flow direction, the electromagnetic valve is connected with the computer through a second signal line, the nitrogen gas bottle is connected with the first gas pipe between the second pressure gauge and the electromagnetic valve through a second gas pipe, and the second gas pipe is provided with a second valve.
5. The coal body adsorption desorption deformation anisotropy synchronous testing device according to claim 4, characterized in that: the temperature control system comprises a constant temperature water bath box, and the adsorption and desorption tank is arranged in the constant temperature water bath box.
6. The coal body adsorption desorption deformation anisotropy synchronous testing device according to claim 5, characterized in that: the device also comprises a desorption and gas collection device which comprises six desorption measuring tubes and a water containing tank; six desorption measuring tubes are arranged side by side, are inserted below the water surface in the water containing tank with the openings facing downwards, are connected in series through rubber tubes at the tops, each rubber tube is clamped with a clamp, the lower end opening of one desorption measuring tube is connected with a vent pipe through a desorption tube, and a third valve is arranged on the desorption tube.
7. The coal body adsorption desorption deformation anisotropy synchronous testing device according to claim 6, characterized in that: the vacuum system comprises a rotary vane type vacuum pump, the rotary vane type vacuum pump is connected with the vent pipe through a vacuum pipe, a fourth valve is arranged on the vacuum pipe, and a vacuum gauge is connected to the rotary vane type vacuum pump.
8. A testing method of a coal body adsorption desorption deformation anisotropy synchronous testing device is characterized in that: the coal body adsorption desorption deformation anisotropy synchronous testing device comprises the coal body adsorption desorption deformation anisotropy synchronous testing device as defined in any one of claims 1 to 7, and the testing method comprises the following steps:
step one, preparing a coal sample;
bonding the three resistance strain gauges to the surface of the coal sample, arranging a support at the bottom in the adsorption and desorption tank, placing the coal sample on the support, closing the top cover, and fastening the U-shaped buckle to seal the top cover and the adsorption and desorption tank;
step three, detecting the air tightness of the adsorption and desorption tank and the connected pipeline: closing the second valve, the third valve and the fourth valve, opening the first valve and the electromagnetic valve, filling helium with 1MPa into the adsorption and desorption tank by helium gas in the helium tank through the first air pipe and the vent pipe to detect air tightness, keeping the pressure of 1MPa for 12 hours, checking the first pressure gauge and the second pressure gauge every 2 hours, and if the effective readings are all 1MPa, proving that the air tightness of the adsorption and desorption tank and the connected pipelines is good;
step four, putting the adsorption and desorption tank into a constant-temperature water bath box for heating;
step five, vacuumizing the adsorption and desorption tank: closing the first valve, the electromagnetic valve, the second valve and the third valve, opening the fourth valve, starting the rotary vane vacuum pump to continuously vacuumize the adsorption and desorption tank through the vacuum tube and the vent pipe, closing the fourth valve after continuously vacuumizing for 2 hours when 0.1MPa negative pressure is formed, stopping vacuumizing, and starting the strain gauge to record the change of the strain number value every 1s in the vacuumizing stage;
opening a second valve and an electromagnetic valve, filling nitrogen into the adsorption and desorption tank by the nitrogen in a nitrogen bottle, enabling the nitrogen in the adsorption and desorption tank to reach a preset gas pressure, displaying the reflection condition of the pressure in the adsorption and desorption tank on a computer through a pressure sensor, and controlling and adjusting the electromagnetic valve, so that the gas pressure in the adsorption and desorption tank is in a stable pressure state, the coal sample is subjected to adsorption expansion deformation, recording the value change acquired by a resistance strain gauge every 1s, and considering that the coal sample reaches adsorption balance until the data acquired by the strain gauge is unchanged, namely when a strain curve on the computer is approximate to a horizontal straight line;
step seven, after the coal sample reaches the adsorption balance, quickly closing the second valve and the electromagnetic valve, simultaneously opening the third valve, and performing adsorption desorptionThe nitrogen in the suction tank enters the desorption measuring tube through the vent pipe and the desorption pipe, the numerical value change monitored by the resistance strain gauge adhered to the coal sample is continuously monitored through the strain gauge, and the change rate of the strain is less than 2 multiplied by 10-4h-1When the coal desorption and gas collection device is used, the desorption balance can be considered to be achieved, meanwhile, the monitoring desorption and gas collection device displays the numerical value change condition of the gas desorption amount, the desorption deformation amount and the accumulated desorption amount are correlated and compared, and the coal desorption deformation condition is comprehensively reflected;
and step eight, repeating the step five to the step seven, changing the set value of the gas pressure in the adsorption and desorption tank, and measuring the adsorption-desorption strain of the coal sample under different pressure conditions.
9. The testing method of the coal body adsorption desorption deformation anisotropy synchronous testing device according to claim 8, characterized in that: the specific processes of the first step and the second step are as follows:
according to a coal object to be researched, a corresponding coal sample is taken, the size of a coal block is measured by using a ruler, a cutting route is divided by using a color pen, and in order to meet the requirement that the adsorption and desorption deformation rules of a coal bed in three directions under different gas pressures can be simultaneously tested at one time, a cubic block sample is selected for testing the adsorption and desorption deformation anisotropy; cutting and processing a coal block into a cube coal sample with the side length of 60mm, wiping the surface of the coal sample with alcohol before the coal sample is tested, slightly polishing the surface with sand paper to be smooth, then drying the coal sample in a drying oven at 100 ℃ for 48h, cooling, and sealing and storing the coal sample with a freshness protection package for later use; selecting places without obvious cracks on the surface on three sides of the coal sample, and respectively sticking the three resistance strain gauges on the three sides by glue.
10. The testing method of the coal body adsorption desorption deformation anisotropy synchronous testing device according to claim 8, characterized in that: in the fifth step, the coal body sample is subjected to shrinkage deformation in the vacuumizing stage, after half an hour, the shrinkage deformation of the coal body sample tends to be balanced, and at the moment, air and moisture in the coal body sample are exhausted; the difference of the strain between the vertical bedding direction and the vertical surface cleat direction is small, and the difference of the strain between the vertical bedding direction and the vertical surface cleat direction is large; the deformation of the coal sample cracks plays a main control role in the vacuum pumping process, and gas is mainly gathered in large pores and cracks;
in the sixth step, after nitrogen with certain pressure is filled in the adsorption and desorption tank, larger confining pressure can be generated around the coal sample instantly, as the coal sample is placed on the bracket, six surfaces of the coal sample can be subjected to the confining pressure, the adsorption and expansion deformation of the coal sample is ignored at the moment and mainly expressed as compression deformation, after the nitrogen in the adsorption and desorption tank reaches the preset pressure, the nitrogen gas rapidly enters cracks and pores in the coal sample and is subjected to seepage and diffusion, the adsorption gas enables the micro-pores and micro-cracks of the coal sample to be reduced in surface energy, the thickness of a surface layer is increased, and free gas enables the volumes of the micro-pores and the micro-cracks to be increased, so that the coal sample is subjected to expansion deformation;
in the seventh step, the coal sample is not simply shrunk and deformed all the time in the nitrogen desorption process, and an instant expansion deformation process can occur when high-pressure gas is rapidly discharged; the deformation in the vertical bedding direction is large, the deformation in the parallel bedding vertical plane in the cutting direction is small, and the cutting direction of the vertical end of the parallel bedding has no obvious change; starting an elastic recovery deformation stage along with the expansion deformation of the coal sample, wherein the elastic recovery deformation stage has extremely short duration and large deformation; in the desorption shrinkage deformation stage of the coal sample, along with the continuous increase of desorption time, the slope of a shrinkage deformation curve is gradually reduced until the slope approaches to 0 finally, the relative shrinkage deformation of the coal sample is continuously increased, and finally an approximate stable value is reached;
in addition, in the seventh step, the coal sample is subjected to volume strain in the nitrogen desorption process v Defined as the amount of change in unit volume of the object, the magnitude is expressed as:
wherein the content of the first and second substances,1、 2 、 3 are respectively provided withExpressed as vertical bedding strain, parallel bedding vertical plane cleaving strain and parallel bedding vertical end cleaving strain; in addition, the cumulative amount of desorption of the coalQ t At the time of desorptiontThe size of the coal body desorption gas; in the coal body desorption deformation process, in the initial desorption stage, the coal body desorption gas speed is higher than the coal body deformation speed, and then the coal body deformation speed is gradually higher than the desorption gas speed; overall, the volume strain and the gas desorption cumulant have better positive correlation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910321083.7A CN111829917A (en) | 2019-04-22 | 2019-04-22 | Coal body adsorption desorption deformation anisotropy synchronous testing device and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910321083.7A CN111829917A (en) | 2019-04-22 | 2019-04-22 | Coal body adsorption desorption deformation anisotropy synchronous testing device and method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111829917A true CN111829917A (en) | 2020-10-27 |
Family
ID=72912159
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910321083.7A Pending CN111829917A (en) | 2019-04-22 | 2019-04-22 | Coal body adsorption desorption deformation anisotropy synchronous testing device and method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111829917A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115711798A (en) * | 2022-11-14 | 2023-02-24 | 中国矿业大学 | Test method for measuring Biot coefficient of dual-pore coal rock matrix system |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203053399U (en) * | 2012-12-21 | 2013-07-10 | 中煤科工集团重庆研究院 | Coal body deformation testing device during gas absorbing and desorbing processes |
| US20150362419A1 (en) * | 2013-02-08 | 2015-12-17 | Schumberger Technology Corporation | Apparatus and methodology for measuring properties of microporous material at multiple scales |
| CN105352846A (en) * | 2015-12-03 | 2016-02-24 | 中国矿业大学 | Testing device and method for tectonic coal desorption gas energy distribution curve |
| CN107219148A (en) * | 2017-05-19 | 2017-09-29 | 河南理工大学 | A kind of experimental method for being applied to coal body adsorption-desorption deformation test under HTHP |
| CN107860681A (en) * | 2017-11-08 | 2018-03-30 | 石家庄铁道大学 | A kind of the gas adsorption desorption properties test device and its method of testing of pre- adsorption moisture coal sample |
| CN209821006U (en) * | 2019-04-22 | 2019-12-20 | 河南理工大学 | Synchronous testing device for coal body adsorption desorption deformation anisotropy |
-
2019
- 2019-04-22 CN CN201910321083.7A patent/CN111829917A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203053399U (en) * | 2012-12-21 | 2013-07-10 | 中煤科工集团重庆研究院 | Coal body deformation testing device during gas absorbing and desorbing processes |
| US20150362419A1 (en) * | 2013-02-08 | 2015-12-17 | Schumberger Technology Corporation | Apparatus and methodology for measuring properties of microporous material at multiple scales |
| CN105352846A (en) * | 2015-12-03 | 2016-02-24 | 中国矿业大学 | Testing device and method for tectonic coal desorption gas energy distribution curve |
| CN107219148A (en) * | 2017-05-19 | 2017-09-29 | 河南理工大学 | A kind of experimental method for being applied to coal body adsorption-desorption deformation test under HTHP |
| CN107860681A (en) * | 2017-11-08 | 2018-03-30 | 石家庄铁道大学 | A kind of the gas adsorption desorption properties test device and its method of testing of pre- adsorption moisture coal sample |
| CN209821006U (en) * | 2019-04-22 | 2019-12-20 | 河南理工大学 | Synchronous testing device for coal body adsorption desorption deformation anisotropy |
Non-Patent Citations (2)
| Title |
|---|
| 祝捷;唐俊;传李京;王学;: "煤吸附解吸气体变形的力学模型研究", 中国科技论文, no. 17, 8 September 2015 (2015-09-08) * |
| 魏彬: "煤岩吸附—解吸变形各向异性特征试验分析", 石油地球物理勘探, vol. 54, no. 1, 15 February 2019 (2019-02-15), pages 112 - 117 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115711798A (en) * | 2022-11-14 | 2023-02-24 | 中国矿业大学 | Test method for measuring Biot coefficient of dual-pore coal rock matrix system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN209821006U (en) | Synchronous testing device for coal body adsorption desorption deformation anisotropy | |
| CN106970000B (en) | Shale gas adsorption method for evaluating coal/shale ultrahigh-pressure gas adsorption and seepage experiments | |
| CN105910971B (en) | The simultaneous measuring method of rich organic matter compact rock core gas permeability and diffusion coefficient | |
| CN102901803B (en) | Water-gas different adsorption-desorption-seepage experimental method for loaded coal containing methane | |
| CN107219148B (en) | Experimental method suitable for coal body adsorption and desorption deformation test under high temperature and high pressure | |
| CN104502224B (en) | Saturation water Coal Under rock isothermal desorption curve determination device and method | |
| CN104729948B (en) | Coal containing methane gas aqueous vapor two phase fluid flow experimental system and method | |
| CN101408493B (en) | Method and apparatus for measuring adsorbance-deformation-permeability coefficients of material | |
| CN104897554B (en) | Hypotonic rock gas pervasion test device and method of testing under vapor heat mechanics coupling effect | |
| CN107063968B (en) | Concrete gas permeability testing device and method | |
| CN201819853U (en) | Novel osmotic suction controlled comprehensive tester for unsaturated soil | |
| CN105547908A (en) | Experimental testing equipment for mixed gas adsorption capacity of coal rock/shale | |
| CN103776979A (en) | Simulation test method and device for inhibiting methane desorption effect by coal seam water injection | |
| CN108303509B (en) | Device and method for correcting free amount calculation of coal bed gas and measuring residual adsorption amount | |
| CN109030318B (en) | Pressure chamber structure and permeability testing system | |
| CN107014714B (en) | Be applicable to coal body adsorption desorption deformation test device under high temperature and high pressure | |
| CN111829917A (en) | Coal body adsorption desorption deformation anisotropy synchronous testing device and method | |
| CN202661326U (en) | Multifunctional unsaturated soil three-axis test device capable of circularly applying suction force | |
| CN102798586B (en) | Novel testing system for testing air permeability of micro air-permeable film | |
| CN108318666A (en) | The more PROCESS COUPLING experimental rigs of rock, gas of Unconventional gas | |
| CN214174090U (en) | Coal rock anisotropic adsorption expansion and permeability testing device | |
| CN108645740B (en) | Method and device for measuring back-flow rate of rock core after self-absorption of fracturing fluid | |
| CN102914485A (en) | Device and method for testing deviation factor of natural gas in porous medium | |
| CN111929214A (en) | Coal bed gas seepage and coal adsorption methane desorption experimental device and method under ultrasonic action | |
| CN111323359A (en) | Device and method for measuring spontaneous imbibition of rock core of high-pressure natural gas-water system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |