CN104819910A - Experimental device and method for measuring amount of gas adsorbed by large quantity of coal samples under condition of normal pressure - Google Patents

Abstract

Aiming at the problem that the research on the adsorption characteristics of coal to gas under normal temperature and pressure conditions is still rare in the prior art, the present invention discloses an experimental device and method for the adsorption of power plant flue gas by a large amount of coal samples under normal pressure conditions , belonging to the technical field of measuring the amount of gas adsorbed by coal samples. The experimental device mainly includes: pipelines, gas supply devices, sealed adsorption cylinders, vacuum pumps and data acquisition and detection devices. The experimental method mainly includes the following steps: evacuating the coal sample, collecting the concentration of the flue gas of the power plant before adsorption, reaching the saturated adsorption of the coal sample at normal temperature and pressure, and collecting the concentration of the gas in the adsorption cylinder after the adsorption. The invention simulates the determination of the saturated adsorption capacity of coal samples adsorbing power plant flue gas under the temperature and pressure of the mine goaf. The invention provides a basic experimental device for measuring the adsorption amount of coal samples to power plant flue gas under normal temperature and pressure, and provides experimental support for directly injecting power plant flue gas into goafs instead of traditional _N2 and _CO2 injection.

Description

Experimental device and method for measuring the amount of gas adsorbed by a large coal sample under normal pressure

technical field

The invention belongs to the technical field of measuring the amount of gas adsorbed by coal samples, in particular to an experimental device and method for measuring the amount of gas adsorbed by large-scale coal samples under normal pressure conditions.

Background technique

my country is a country with abundant coal resources. With the substantial improvement of coal production efficiency and coal output, a large amount of floating coal is left in the goaf, and coal mine fires occur frequently. In addition, during the mining, utilization and processing of coal, coal combustion produces a large amount of CO ₂ gas. Due to the massive emission of CO ₂ gas, it leads to global warming and various extreme climate phenomena. Therefore, in coal mining At the same time, it is an urgent problem to be solved in our country to study new methods that can not only reduce the occurrence of mine disasters but also reduce the emission of CO ₂ gas.

Among the various greenhouse gases that cause climate change, the warming effect of CO ₂ emitted by human activities accounts for 63% of the total warming effect of all greenhouse gases, and CO ₂ has become the gas that has the greatest impact on climate change. It is well known that the ability of coal to adsorb CO ₂ is stronger than that of N ₂ . In recent years, with the development of coal adsorption science, more and more scholars are committed to using CO ₂ instead of N ₂ for fire prevention and extinguishing technology. In order to meet the needs of mine fire prevention and extinguishment, inert gas (mainly N ₂ and CO ₂ ) fire prevention technology has gradually become one of the effective technical measures to prevent and control internal fires in coal seams. In recent years, some scholars have proposed that the flue gas (mainly composed of N ₂ and CO ₂ ) produced by coal combustion be injected into non-minable coal seams or goafs. This method can not only replace nitrogen injection but also effectively prevent and control coal spontaneous combustion fire, save energy waste caused by nitrogen production, and can also achieve CO ₂ gas storage and reduce CO ₂ gas emissions into the atmosphere.

The adsorption of coal to gas is mainly physical adsorption. Most of the research on coal to gas adsorption is based on the results of isothermal adsorption experiments to obtain the adsorption capacity of coal to gas under different equilibrium pressures. The selected devices are: HCA high pressure capacity method adsorption device, The IS-100 gas isothermal adsorption and desorption instrument introduced by Terra Tek of the United States, the AST-2000 large sample adsorption/desorption simulation experiment instrument of Xi'an University of Science and Technology, etc. Although the isothermal adsorption experiment has established the theoretical model and mathematical expression of the isothermal adsorption line, so far, the research has used the high-pressure volumetric method of coal to conduct the isothermal adsorption experiment, that is, to select different pressure points for the test of the adsorption capacity, so the pressure point All of them are selected in the range above the atmospheric pressure, so the research on the adsorption characteristics of coal to gas under the condition of normal temperature and pressure is still rare.

Contents of the invention

The purpose of the present invention is to provide an experiment for measuring the amount of gas adsorbed by a large coal sample under normal pressure conditions to solve the problem that the research on the adsorption characteristics of coal to gas under normal temperature and pressure conditions is still rare in the prior art. Apparatus and methods. Therefore, it is more convenient and accurate to simulate the temperature and pressure of the goaf in the mine, and determine the adsorption and storage mechanism of the gas left in the goaf.

An experimental device for measuring the amount of gas adsorbed by a large coal sample under normal pressure conditions, including a pipeline, a gas supply device, a sealed adsorption cylinder, a vacuum pump, and a data acquisition and detection device; the gas supply device, the vacuum pump, and the data acquisition and detection device They are respectively connected to the sealed adsorption cylinder through pipelines;

Wherein, the gas supply device is a high-pressure gas cylinder, preferably, the gas supply device also includes a gas delivery pump, the high-pressure gas cylinder and the gas delivery pump are connected through a pipeline, and a pressure regulator is installed at the outlet of the high-pressure gas cylinder ;

The sealed adsorption cylinder is used for loading coal samples, and the cylinder is provided with a pressure gauge, a gas injection port, a degassing port and a sample outlet; the gas supply device is connected with the gas injection port of the sealed adsorption cylinder through a pipeline, and the vacuum pump is connected with the gas injection port through a pipeline. The degassing port of the adsorption cylinder is connected, and the data acquisition and detection device is connected with the sample outlet of the adsorption cylinder through a pipeline; preferably, the adsorption cylinder is made of stainless steel;

The data acquisition and detection device is a gas chromatograph and a workstation.

The experimental method for measuring the amount of gas adsorbed by a large sample size coal sample under normal pressure using the above-mentioned device comprises the following steps:

(1) Preparation of experimental gas

The simulated experimental gas is prepared according to the actual composition and volume fraction of the gas to be studied, and the gas that is not adsorbed by coal is used as the background gas;

(2) Degassing

Check the airtightness of the sealed adsorption cylinder, then put the dry large-scale pulverized coal sample into the sealed adsorption cylinder, and degas the adsorption cylinder with a vacuum pump after sealing;

(3) Gas injection and adsorption

After the degassing is completed, inject gas into the adsorption cylinder through the gas supply device until the pressure in the cylinder reaches 0.1MPa, then use a gas chromatograph to measure the initial volume fraction of each gas component to be measured in the cylinder and record it as the value before adsorption;

(4) Measure and calculate the adsorption capacity

Since the pulverized coal sample can absorb gas, the amount and composition of the gas in the free gas phase will change with time; therefore, at regular intervals, preferably every 12 hours, use a gas chromatograph to measure the free gas in the adsorption cylinder. The volume fraction of each component to be measured in the gas phase, and then calculate the adsorption amount of the pulverized coal sample to the gas through the adsorption amount calculation formula derived from the ideal gas state equation;

According to the ideal gas state equation, the process of deriving the calculation formula of adsorption capacity is as follows:

P _i V _i =n _i RT

P _K V _K =n _K RT

Among them, P _i is the partial pressure of a certain gas component to be measured in the sealed adsorption cylinder before adsorption, unit: Pa; V _i is the volume of a certain gas component to be measured in the sealed adsorption cylinder before adsorption, unit: m ³ ; n _i P _K is the total gas pressure in the sealed adsorption cylinder before adsorption, unit: Pa; V _K is the total volume of gas in the sealed adsorption cylinder, Unit: m ³ ; n _K is the amount of total gas substances in the sealed adsorption cylinder, unit: mol; T is the system temperature, unit: K; R is the gas constant of an ideal gas, about 8.314J/(mol K);

Since the temperature remains constant during the adsorption process and the total volume of the adsorption cylinder remains constant, the ratio of the gas pressure to the amount of the contained substances is the same, namely:

In the formula, Indicates the volume fraction of a certain gas component to be measured in the sealed adsorption cylinder before adsorption, %;

From this, P _i can be calculated:

Putting the above formula into the ideal gas state equation, the amount of the substance to be measured in the sealed adsorption cylinder before adsorption can be calculated as:

The above formula is also applicable to the calculation of the amount of a certain gas component to be measured in the sealed adsorption cylinder after adsorption, namely:

Among them, n _i ′ is the amount of a certain gas component to be measured in the sealed adsorption cylinder at a certain time point after adsorption, unit: mol; P _i ′ is a certain gas group to be measured in the sealed adsorption cylinder at a certain time point after adsorption Partial pressure, unit: Pa; V _i ′ is the volume of a certain gas component to be measured in the sealed adsorption cylinder at a certain time point after adsorption, unit: m ³ ; is the volume fraction of a certain gas component to be measured in the sealed adsorption cylinder at a certain time point after adsorption, %; P _K ′ is the total gas pressure in the sealed adsorption cylinder at a certain time point after adsorption, unit: Pa;

Then, according to the difference in the amount of the gas component to be measured before and after adsorption, the volume of the gas adsorbed by coal is obtained as:

$\mathrm{<span\; class="notranslate">\; V</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{\mathrm{<span\; class="notranslate">\; 3</span>}}$

Among them, V is the adsorption volume of gas per gram of coal at a certain time point, unit: cm ³ g ^-1 ; V _m is the molar volume of gas at normal temperature and pressure, 24.5L/mol; m is the mass of coal, unit: g;

The volume fraction before and after adsorption of a certain gas component to be tested measured by the gas chromatograph is brought into the above formula to obtain the amount of gas adsorbed by the coal sample;

In the above step (2), the method for checking the airtightness of the sealed adsorption cylinder is: after injecting gas into the adsorption cylinder, close the sealed adsorption cylinder, and if the pressure of the adsorption cylinder does not change within 24 hours, the airtightness meets the requirements; , the pressure of the injected gas is ≥ 3 atmospheres and the maximum pressure does not exceed the maximum pressure that the cylinder can withstand;

The method used in the detection of the above-mentioned gas chromatograph is a single-point calibration method.

The definition of large sample size in the present invention is that the amount of coal samples used by traditional adsorption instruments is very small, only a few grams to tens of grams, and the method of the present invention can measure the amount of coal samples in kilograms to ten kilograms.

Compared with the prior art, the present invention has the advantages of

1. The invention includes a gas supply system, a degassing system (vacuum pump), a flue gas adsorption and desorption system (sealed adsorption cylinder) and a data acquisition system. Its structure is simple, and it can be used to simulate the temperature and pressure of the mine goaf. The determination of saturated adsorption capacity of power plant flue gas provides experimental support for injecting power plant flue gas directly into the goaf instead of traditional N ₂ and CO ₂ injection.

2. The adsorption value measured by the method of the present invention is closer to the actual situation. Since the amount of coal sample used in the conventional adsorption instrument is small, and the adsorption amount of coal is very small under normal temperature and pressure conditions, it is difficult to directly measure the adsorption amount under normal pressure conditions, and can only be based on the numerical simulation of the adsorption isotherm. Calculated. The volume of the adsorption cylinder selected by the present invention is 55L, which can test the adsorption of a large number of coal samples, and provide a basic experimental device for the determination of the adsorption capacity of power plant flue gas by coal samples at normal temperature and pressure.

3. The data acquisition system of the present invention adopts a gas chromatograph with an automatic sampling device, which can monitor the volume fraction of free gas in the adsorption cylinder in real time. The use of automatic valve sampling can reduce the error of artificial sampling and improve the accuracy of the experiment. Rate.

4. The device of the present invention is simple and easy to operate.

5. The present invention can not only detect the value of the adsorption amount of coal to a single gas, but also simultaneously detect the values of the adsorption amount of coal to two or more gases.

Description of drawings

Fig. 1, the schematic diagram of experimental device of the present invention;

Among them, 1. Pipeline, 2. Gas supply device, 3. Sealed adsorption cylinder, 4. Vacuum pump, 5. Data acquisition and detection device, 6. Pressure gauge, 7. Gas injection port, 8. Degassing port, 9. Sample outlet , 10, high-pressure gas cylinder, 11, gas chromatograph, 12, workstation, 13, air generator, 14, carrier gas cylinder.

Detailed ways

An experimental device for measuring the amount of gas adsorbed by a large coal sample under normal pressure conditions, including a pipeline, a gas supply device, a sealed adsorption cylinder, a vacuum system, and a data acquisition and detection device; the gas supply device, the vacuum system and the data acquisition The detection devices are respectively connected to the sealed adsorption cylinder through pipelines;

The gas supply device includes a high-pressure gas cylinder, preferably, the gas supply device also includes a gas delivery pump, and a pressure regulator is installed at the outlet of the high-pressure gas cylinder;

The sealed adsorption cylinder is used to load coal samples, and the cylinder is equipped with a pressure gauge, a gas injection port, a degassing port and a sample outlet; preferably, the adsorption cylinder is made of stainless steel; the adsorption cylinder adopts a self-made stainless steel reaction kettle with a capacity of 55L, and the adsorption cylinder There is a sealing ring inside to ensure the sealing of the adsorption cylinder. The pressure limit of the adsorption cylinder is 5MPa; the pressure and vacuum dual-purpose meter is used to measure the real-time change of the pressure in the adsorption cylinder, and the range is -0.1MPa～5MPa;

The data acquisition and detection device is a gas chromatograph and a workstation. The gas chromatograph has a fully automatic air source and a hydrogen generator, and the workstation has a display;

The gas supply device is connected to the gas injection port of the sealed adsorption cylinder through a pipeline, the vacuum pump is connected to the degassing port of the adsorption cylinder through a pipeline, and the data acquisition and detection device is connected to the sample outlet of the adsorption cylinder through a pipeline.

Example 1

An experimental device for measuring the amount of gas adsorbed by a large coal sample under normal pressure conditions, comprising a pipeline 1, a gas supply device 2, a sealed adsorption cylinder 3, a vacuum pump 4, and a data acquisition and detection device 5;

Pipeline 1 is a high-pressure rubber hose with an inner diameter of 3mm and can withstand a gas pressure of 10MPa;

The sealed adsorption cylinder 3 is made of stainless steel and is used to load coal samples. The adsorption cylinder 3 is equipped with a pressure gauge 6, a gas injection port 7, a degassing port 8 and a sample outlet 9, and an air supply valve is installed on the gas injection port 7, and a gas supply valve is installed on the degassing port. 8 is equipped with a degassing valve, and a sampling valve is installed on the sample outlet 9; the adsorption cylinder 3 adopts a self-made stainless steel reaction kettle with a capacity of 55L, and the adsorption cylinder 3 is provided with a sealing ring to ensure the sealing of the adsorption cylinder. The pressure limit of the pressure gauge is 5MPa; the pressure gauge 6 is a dual-purpose gauge for pressure and vacuum, which is used to measure the real-time change of the pressure in the adsorption cylinder, and the range is -0.1MPa～5MPa;

The gas supply device 2 is a high-pressure gas cylinder 10 equipped with a pressure regulator at the outlet. The high-pressure gas cylinder 10 is equipped with simulated experimental gas, and the pressure regulator adjusts the gas to the pressure required for the experiment. Road 1 is delivered to the gas injection port 7 of the adsorption cylinder 3, and the gas injection volume is controlled by the gas supply valve on the adsorption cylinder 3;

The vacuum pump 4 is an impeller-type vacuum pump, and the vacuum pump 4 is connected to the degassing port 8 on the sealed adsorption cylinder 3 through the pipeline 1, and the pumping volume is controlled by the degassing valve on the sealed adsorption cylinder 3;

The data acquisition and detection device 5 includes a gas chromatograph 11 and a workstation 12. The gas chromatograph 11 is the SP-3400 gas chromatograph analyzer produced by Beijing North Branch, and the workstation 12 is the BF-2002 chromatographic workstation produced by Beijing North Branch. The gas chromatograph 11 has an air generator 13 and a hydrogen generator; the gas chromatograph 11 is connected to the sample outlet 9 of the adsorption cylinder through the pipeline 1, and is controlled by the sampling valve on the sealed adsorption cylinder 3 to inject samples into the gas chromatograph; the carrier gas used Determined by the nature of the gas to be measured.

When using this device:

1) Inject air into the sealed adsorption cylinder 3:

Seal the airtight adsorption cylinder 3, close the degassing valve on the degassing port 8 and the sampling valve on the sample outlet 9, open the gas supply valve on the gas injection port 7; The medium gas is adjusted to the pressure required for the experiment, and the gas in the high-pressure cylinder is delivered to the adsorption cylinder through the gas injection port 7 by the delivery pump, and the pressure change in the cylinder is monitored through the pressure gauge 6 on the sealed adsorption cylinder 3.

2) Extract air from the sealed adsorption cylinder 3

Seal the airtight adsorption cylinder 3, close the gas supply valve on the gas injection port 7 and the sampling valve on the sample outlet 9, open the degassing valve on the degassing port 8; open the vacuum pump 4, and extract the gas in the cylinder through the degassing port 8, And by the pressure gauge 6 on the sealing adsorption cylinder 3, the pressure change in the cylinder is monitored.

3) Sampling from the sealed adsorption cylinder 3

Seal the airtight adsorption cylinder 3, close the gas supply valve on the gas injection port 7 and the degassing valve on the degassing port 8, open the sampling valve on the sample outlet 9; the gas in the cylinder enters the gas chromatograph 11 by the sample outlet 9, And the volume fraction of each component in the gas is calculated by the workstation 12 .

Example 2

Utilize the device of embodiment 1 to measure the experimental method of large sample volume coal sample adsorption gas amount under normal pressure condition, comprise the steps:

(1) Weigh 5kg of pulverized coal sample, put it into drying box and dry for 6h;

(2) Check the air tightness of the device: open the gas injection port, close the degassing port and sample outlet, inject argon into the adsorption cylinder until the pressure in the cylinder is 1MPa, close the gas injection port, and observe that the pressure of the adsorption cylinder does not change within 24 hours Then the airtightness of the adsorption cylinder meets the requirements;

(3) Preparation of experimental gas: preparation of an experimental gas containing about 79% N ₂ and using argon as the background gas for the adsorption experiment of coal to N _{2 ;} The experimental gas is used for the adsorption experiment of coal to _CO2; the experimental gas containing about 79% _N2 , about 16.5% _CO2 and argon as the background gas is prepared for the adsorption experiment of coal to flue gas;

(4) Degassing: Put the processed pulverized coal sample into the adsorption cylinder, seal the adsorption cylinder, close the gas injection port and the sample outlet, open the degassing port, use the vacuum pump to vacuum the cylinder, and pass the pressure on the adsorption cylinder. The table reads that the vacuum degree in the adsorption cylinder is 0.0004MPa;

(5) Gas injection and adsorption: After degassing is completed, close the degassing port and vacuum pump, open the gas injection port, inject gas into the adsorption cylinder through a high-pressure gas cylinder until the pressure in the cylinder reaches 0.1MPa, close the gas injection port, and immediately open the outlet. At the sample port, the gas is collected by the gas chromatograph and the initial volume fraction of each gas component to be measured in the cylinder is measured and recorded as the value before adsorption; the quantitative method of the gas chromatograph is a single-point calibration method;

(6) Determination of adsorption amount: from the beginning of the experiment to the end of the experiment, the amount of gas in the free phase will change. Therefore, the sample outlet is opened once every 12 hours, and each gas group to be measured in the free phase in the adsorption cylinder is measured by a gas chromatograph. The quantitative method of gas chromatography is the single-point calibration method; and the adsorption amount of coal to gas is calculated through the ideal gas state equation, and the adsorption amount calculation formula is derived according to the ideal gas state equation. The process is as follows:

P _i V _i =n _i RT

P _K V _K =n _K RT

Among them, P _i is the partial pressure of a certain gas component to be measured in the sealed adsorption cylinder before adsorption, unit: Pa; V _i is the volume of a certain gas component to be measured in the sealed adsorption cylinder before adsorption, unit: m ³ ; n _i P _K is the total gas pressure in the sealed adsorption cylinder before adsorption, unit: Pa; V _K is the total volume of gas in the sealed adsorption cylinder, Unit: m ³ ; n _K is the amount of total gas substances in the sealed adsorption cylinder, unit: mol; T is the system temperature, unit: K; R is the gas constant of an ideal gas, about 8.314J/(mol K);

Since the temperature remains constant during the adsorption process and the total volume of the adsorption cylinder remains constant, the ratio of the gas pressure to the amount of the contained substances is the same, namely:

In the formula, Indicates the volume fraction of a certain gas component to be measured in the sealed adsorption cylinder before adsorption, %;

From this, P _i can be calculated:

Putting the above formula into the ideal gas state equation, the amount of the substance to be measured in the sealed adsorption cylinder before adsorption can be calculated as:

The above formula is also applicable to the calculation of the amount of a certain gas component to be measured in the sealed adsorption cylinder after adsorption, namely:

Among them, n _i ′ is the amount of a certain gas component to be measured in the sealed adsorption cylinder at a certain time point after adsorption, unit: mol; P _i ′ is a certain gas group to be measured in the sealed adsorption cylinder at a certain time point after adsorption Partial pressure, unit: Pa; V _i ′ is the volume of a certain gas component to be measured in the sealed adsorption cylinder at a certain time point after adsorption, unit: m ³ ; is the volume fraction of a certain gas component to be measured in the sealed adsorption cylinder at a certain time point after adsorption, %; P _K ′ is the total gas pressure in the sealed adsorption cylinder at a certain time point after adsorption, unit: Pa;

Then, according to the difference in the amount of the gas component to be measured before and after adsorption, the volume of the gas adsorbed by coal is obtained as:

$\mathrm{<span\; class="notranslate">\; V</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{\mathrm{<span\; class="notranslate">\; 3</span>}}$

Among them, V is the adsorption volume of gas per gram of coal at a certain time point, unit: cm ³ g ^-1 ; V _m is the molar volume of gas at normal temperature and pressure, 24.5L/mol; m is the mass of coal, unit: g;

The volume fraction of a gas component to be tested measured by gas chromatography before and after adsorption is brought into the above formula to obtain the amount of gas adsorbed by the coal sample.

The following is an example of the results of simulating the coal sample adsorption of flue gas in Tongxin Mine for 12 hours. The specific data are shown in Table 1:

Table 1. Adsorption capacity of coal samples adsorbing flue gas for 12 hours

Moreover, the pressure in the cylinder before adsorption is 126025Pa, and the pressure in the cylinder after adsorption for 12 hours is 116825Pa;

Taking the calculation of N ₂ adsorption capacity as an example, where before the adsorption P _k =126025Pa, V _i =55L, R=8.314J/(mol·K), T=293.15K,

but, ${\mathrm{no}}_i=\frac{0.6698*126025*55{*10}^{-3}}{8.314*293.15}=1.905\mathrm{mol},$

After adsorption P _k '=116825PPa, V _i '=55L, R=8.314J/(mol·K), T=293.15K,

but ${{\mathrm{no}}_i}^{\&prime;}=\frac{0.704*116825*55{10}^{-3}}{8.314*293.15}=1.856\mathrm{mol}$

but $V=\frac{(1.905-1.856)*24.5}{5000}*{10}^3=0.24{\mathrm{cm}}^3/g$

That is, under normal temperature and pressure conditions, the adsorption capacity of N ₂ per gram of coal is 0.24 cm ³ ; similarly, the calculation method of CO ₂ adsorption is also as above.

Example 3

According to the method of implementation 2, using the flue gas in Example 2, under normal temperature and pressure conditions, the adsorption capacity of 5 kg of pulverized coal samples from Tashan Mine after 24 hours of adsorption of nitrogen, carbon dioxide and power plant flue gas was measured.

The specific experimental results are shown in Table 2.

Example 4

According to the method of implementation 2, adopt the flue gas in the embodiment 2 and the self-made capacity is the airtight adsorption cylinder of 100L, under the condition of normal temperature and pressure, measure 12kg of pulverized coal sample of Tongxin Mine respectively after adsorbing nitrogen, carbon dioxide and power plant flue gas for 24h the amount of adsorption.

The specific experimental results are shown in Table 2.

Example 5

According to the method of Implementation 2, using the flue gas in Example 2, under normal temperature and pressure conditions, the adsorption capacity of 6 kg of pulverized coal samples from Gaohai Mine was determined after 24 hours of adsorption of nitrogen, carbon dioxide and power plant flue gas respectively.

The specific experimental results are shown in Table 2.

Example 6

According to the method of implementation 2, using the flue gas in Example 2, under normal temperature and pressure conditions, the adsorption capacity of 4 kg of pulverized coal samples from Anshun Mine after 24 hours of adsorption of nitrogen, carbon dioxide and power plant flue gas were measured.

The specific experimental results are shown in Table 2.

Table 2 Comparison of the amount of flue gas adsorbed and the amount of CO ₂ and N ₂ adsorbed by the coal samples of Examples 3 to 6

The results in Table 1 and Table 2 show that the gas adsorption value of the coal sample under normal pressure is very small, much smaller than the saturated adsorption value in the high-pressure volumetric method. Among them, the adsorption capacity of coal sample to _CO2 gas is greater than that of coal to _N2 gas, but the adsorption capacity of coal sample to mixed gas of _N2 and _CO2 is greater than that of coal sample to any single gas. It shows that the adsorption value of coal to power plant flue gas under normal temperature and pressure is greater _than the adsorption value of coal to a single type of N ₂ or _{CO 2} gas. Fire extinguishing technology provides theoretical support.

Claims (8)

1. an experimental device for measuring the amount of gas adsorbed by a large sample size coal sample under normal pressure conditions, is characterized in that, comprises pipeline, gas supply device, sealed adsorption cylinder, vacuum pump and data acquisition detection device; Described gas supply device, The vacuum pump and the data acquisition and detection device are respectively connected to the sealed adsorption cylinder through pipelines. 2. The experimental device for measuring the amount of gas adsorbed by a large coal sample under normal pressure conditions according to claim 1, wherein the gas supply device is a high-pressure gas cylinder. 3. The experimental device for measuring the amount of gas adsorbed by a large sample size coal sample under a kind of normal pressure condition according to claim 2, is characterized in that, the gas supply device also includes a gas delivery pump, and the high-pressure gas cylinder and the gas delivery pump pass through the pipe Road connection, and a pressure regulator is installed at the outlet of the high-pressure gas cylinder. 4. the experimental device of measuring the amount of gas adsorbed by a large sample size coal sample under a kind of normal pressure condition according to claim 1, is characterized in that, described sealed adsorption cylinder is provided with pressure gauge, gas injection port, degassing port and Sample outlet. 5. The experimental device for measuring the amount of gas adsorbed by a large coal sample under normal pressure conditions according to claim 1, wherein the data collection and detection device is a gas chromatograph and a workstation. 6. an experimental method for measuring the amount of adsorbed gas of a large sample size coal sample under a normal pressure condition, adopting the described experimental device of claim 1, is characterized in that, comprises the steps: (1) Preparation of experimental gas The simulated experimental gas is prepared according to the actual composition and volume fraction of the gas to be studied, and the gas that is not adsorbed by coal is used as the background gas; (2) Degassing Check the airtightness of the sealed adsorption cylinder, then put the dry large-scale pulverized coal sample into the sealed adsorption cylinder, and degas the adsorption cylinder with a vacuum pump after sealing; (3) Gas injection and adsorption After the degassing is completed, inject gas into the adsorption cylinder through the gas supply device until the pressure in the cylinder reaches 0.1MPa, then use a gas chromatograph to measure the initial volume fraction of each gas component to be measured in the cylinder and record it as the value before adsorption; (4) Measure and calculate the adsorption capacity Use a gas chromatograph to measure the volume fraction of each component to be measured in the free gas phase in the adsorption cylinder at regular intervals, and then calculate the adsorption amount of the pulverized coal sample to the gas through the adsorption amount calculation formula derived from the ideal gas state equation; The formula for calculating the adsorption capacity is: $\mathrm{<span\; class="notranslate">\; V</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}}{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; 10</span>}}^{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; ,</span>$ Among them, V is the adsorption volume of gas per gram of coal at a certain time point, unit: cm ³ g ^-1 ; _ni is the amount of a certain gas component to be measured in the sealed adsorption cylinder before adsorption, unit: mol; n _i ′ is the amount of a certain gas component in the sealed adsorption cylinder at a certain time point after adsorption, unit: mol; V _m is the molar volume of gas at normal temperature and pressure, 24.5L/mol; m is the mass of coal , unit: g; is the volume fraction of a certain gas component to be measured in the sealed adsorption cylinder before adsorption, %; V _i is the volume of a certain gas component to be measured in the sealed adsorption cylinder before adsorption, unit: m ³ ; P _K is the sealed adsorption cylinder before adsorption The total pressure of the gas inside, unit: Pa; is the volume fraction of a certain gas component to be measured in the sealed adsorption cylinder at a certain time point after adsorption, %; V _i ′ is the volume of a certain gas component to be measured in the sealed adsorption cylinder at a certain time point after adsorption, unit: m ³ ; P _K ′ is the total pressure of the gas in the sealed adsorption cylinder at a certain time point after adsorption, unit: Pa; T is the system temperature, unit: K; R is the gas constant of an ideal gas, which is 8.314J/(mol·K). 7. the experimental method of measuring large sample size coal sample adsorption gas amount under a kind of normal pressure condition according to claim 6, is characterized in that, in described step (2), the method for checking the airtightness of sealing adsorption cylinder is : After injecting gas into the adsorption cylinder, close the sealed adsorption cylinder, if the pressure of the adsorption cylinder does not change within 24 hours, the air tightness meets the requirements; Wherein, the pressure of the injected gas is greater than or equal to 3 atmospheres and does not exceed the maximum pressure that the cylinder can withstand. 8 . The experimental method for measuring the amount of gas adsorbed by a large coal sample under normal pressure conditions according to claim 6 , wherein the gas chromatograph is used to measure a single-point calibration method.