CN114487161A - Analysis method and device capable of quantitatively measuring coal low-temperature oxidation gas generation amount - Google Patents
Analysis method and device capable of quantitatively measuring coal low-temperature oxidation gas generation amount Download PDFInfo
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- 239000003245 coal Substances 0.000 title claims abstract description 180
- 238000007254 oxidation reaction Methods 0.000 title claims abstract description 90
- 230000003647 oxidation Effects 0.000 title claims abstract description 85
- 238000004458 analytical method Methods 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 claims abstract description 38
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- 238000010438 heat treatment Methods 0.000 claims abstract description 17
- 238000012216 screening Methods 0.000 claims abstract description 5
- 239000007789 gas Substances 0.000 claims description 221
- 230000001590 oxidative effect Effects 0.000 claims description 20
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 16
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 10
- 229910052757 nitrogen Inorganic materials 0.000 claims description 8
- 238000005259 measurement Methods 0.000 claims description 7
- 239000002817 coal dust Substances 0.000 claims description 6
- 239000000700 radioactive tracer Substances 0.000 claims description 6
- 229910052786 argon Inorganic materials 0.000 claims description 5
- 239000012159 carrier gas Substances 0.000 claims description 5
- 239000001307 helium Substances 0.000 claims description 5
- 229910052734 helium Inorganic materials 0.000 claims description 5
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 5
- 239000010425 asbestos Substances 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 claims description 4
- 239000011261 inert gas Substances 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 4
- 229910052895 riebeckite Inorganic materials 0.000 claims description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 3
- 239000003795 chemical substances by application Substances 0.000 claims description 3
- 238000001035 drying Methods 0.000 claims description 3
- 239000000741 silica gel Substances 0.000 claims description 3
- 229910002027 silica gel Inorganic materials 0.000 claims description 3
- 238000013022 venting Methods 0.000 claims 1
- 239000000843 powder Substances 0.000 abstract description 12
- 238000011160 research Methods 0.000 abstract description 8
- 238000002485 combustion reaction Methods 0.000 abstract description 7
- 230000002269 spontaneous effect Effects 0.000 abstract description 7
- 230000007246 mechanism Effects 0.000 abstract description 4
- 238000004519 manufacturing process Methods 0.000 abstract description 2
- 239000000203 mixture Substances 0.000 abstract 1
- 238000012113 quantitative test Methods 0.000 abstract 1
- 230000008859 change Effects 0.000 description 15
- 238000002474 experimental method Methods 0.000 description 5
- 238000004451 qualitative analysis Methods 0.000 description 4
- 238000004817 gas chromatography Methods 0.000 description 3
- 238000004445 quantitative analysis Methods 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 238000012764 semi-quantitative analysis Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004939 coking Methods 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
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- 238000005065 mining Methods 0.000 description 1
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- 238000012986 modification Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
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- 231100000331 toxic Toxicity 0.000 description 1
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- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
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Abstract
The invention discloses an analysis method and a device capable of quantitatively measuring the generation amount of coal low-temperature oxidation gas, belonging to the technical field of coal mine safety production; the method comprises the following steps: selecting a coal sample of a coal type for crushing; screening a coal powder sample, and filling the coal powder sample into a coal sample tank for later use; placing the coal sample tank in a temperature programming device; heating while introducing gas O2And N2Introducing the mixture into a reactor together according to a certain proportion, and starting slow oxidation; and continuously introducing the gas product generated by oxidation into a gas chromatograph, and respectively measuring the flow, the components and the content of the gas product. The invention uses N2As a trace gas, the specific gas generation amount in a certain time period or a certain temperature period in the low-temperature oxidation process of the coal is obtained by quantifying the gas product; the invention can realize the rapid quantitative test of the coal low-temperature oxidation gas product, thereby determining each coal sample under different low-temperature oxidation conditionsThe generation quality of the component gas guides the basic research of the low-temperature oxidation and spontaneous combustion mechanism of the coal.
Description
Technical Field
The invention relates to the technical field of coal mine safety production, in particular to an analysis method and device capable of quantitatively measuring the generation amount of coal low-temperature oxidation gas.
Background
Coal is the main energy in China, and after coal mining, coal bodies in a broken and stacked state can be subjected to oxidation reaction with oxygen in air to release heat and cause the temperature of the coal bodies to increase, so that the oxidation of the coal bodies is accelerated, more heat is generated, and spontaneous combustion of the coal is finally caused. The spontaneous combustion of coal not only wastes a large amount of coal resources, but also generates a large amount of toxic and harmful gases, and even causes serious environmental problems.
The low-temperature oxidation of coal is considered to be the basic reason causing the spontaneous combustion of coal body, and a series of oxidizing gases such as CO and CO are generated in the low-temperature oxidation process of coal2、CH4、C2H4、C2H2、C2H6Etc., wherein CO and CO are used2The gas content is high. It is considered that the generation concentration of these gases is directly related to the oxidation state of the coal sample, that is, the oxidation state of the coal sample can be determined by the generation concentration of the oxidizing gas. Under the field condition, the oxidation degree of the coal sample in the goaf cannot be measured through the change of temperature, and the oxidation characteristic of the coal sample is generally estimated through the generation concentration of the oxidation gas. Therefore, in order to study the oxidation mechanism of the coal sample, the spontaneous combustion characteristics of the coal are often studied under laboratory conditions by the gas generation process during the low-temperature oxidation of the coal sample.
The existing coal low-temperature oxidation research mainly utilizes a chromatograph to qualitatively analyze gas products generated in the low-temperature oxidation process to explore the change condition of the gas concentration of each component along with the temperature in the coal low-temperature oxidation process, and the change condition of the gas product amount in the coal low-temperature oxidation process cannot be effectively observed, namely, the previous research is qualitative and semi-quantitative analysis, and the specific generation amount of reaction gas cannot be really realized. For example, the amount of gas generated in a certain period of time or a certain temperature period can only obtain the variation trend of the gas, and specific gas yield cannot be obtained.
Therefore, the invention provides an analysis method and a device for quantitatively measuring gas products in the low-temperature oxidation process of coal.
Disclosure of Invention
The invention aims at the technical problems in the prior art and provides an analysis method capable of quantitatively measuring the generation amount of coal low-temperature oxidation gas.
To solve the above technical problem, the present invention comprises the following steps:
1) selecting a coal sample of coal species, stripping an oxide layer on the surface of the coal sample, crushing, and screening coal dust with the particle size of 40-80 meshes for later use;
2) taking 50g of screened coal dust sample, and filling the coal dust sample into a coal sample tank for later use;
3) placing the coal sample tank in a temperature programming device, and heating at a stable heating rate;
4) heating while introducing gas O2And N2Introducing the coal sample into a reactor together according to a certain proportion, so that the coal sample in the coal sample tank begins to be slowly oxidized to generate oxidizing gas;
5) gas products generated by low-temperature oxidation of coal enter a tee joint, one end of the gas products is discharged to the air, the other end of the gas products enters a gas chromatograph through a filter, and when the gas products generated by low-temperature oxidation of coal do not need to be analyzed and measured, a straight-through valve at the empty end is opened for continuous emptying;
6) closing the straight-through valve at the emptying end, opening the straight-through valve at one end of the gas chromatograph, and continuously introducing a gas product generated by oxidation into the gas chromatograph for analysis and determination;
7) the quantity of the oxidizing gas product is determined by the reaction with the known N2Comparing the volume flow and calculating the mass flow corresponding to each component of the gas product;
8) the mass yields corresponding to the individual components of the gaseous product were calculated.
Preferably, the mass flow of the components of the gaseous product is calculated as follows:
in the formula, MiIs the mass flow rate corresponding to each component of the gas product; xiIs the mole fraction of the gas species measured by a gas chromatograph; xN2Is N2The mole fraction of (c); vN2Is N in the gas sample2The volume flow of the nitrogen is inert gas and does not participate in the whole oxidation reaction process, so the volume flow of the nitrogen in the gas sample is equal to the volume flow of the inlet of the coal sample tank; rhoiIs the density of the gas species at standard temperature and pressure.
Preferably, the mass yield of each component of the gaseous product is calculated as follows:
in the formula, YiMass yields for the components of the gaseous product; t is the low temperature oxidation time.
Preferably, the coal powder sample is loaded into the coal sample tank in step 2), a layer of thin asbestos is laid on the upper side of the coal powder sample, then the coal sample cover is screwed down, and the air tightness of the coal sample tank is checked.
Preferably, in the step 3), the coal sample tank is arranged in the programmed heating furnace, the left end opening of the programmed heating furnace is an air inlet opening, and the right end opening of the programmed heating furnace is a coal sample oxidizing gas outlet; the temperature programming furnace is connected with a coal core temperature sensor, and the temperature programming device is also provided with a timing timer.
Preferably, in step 4) O2、N2Respectively as oxidizing gas and tracer gas, and control the gas flow by mass flow meter to mass flow meter's rear end is connected with the three-way valve.
Preferably, two flow lines of the gas product in the steps 5) and 6) are connected with a straight-through valve, when the gas product does not need to be analyzed, the straight-through valve at one end of the vent is opened, the straight-through valve at one end of the gas chromatograph is closed, and the vent is continued; when the gas product is to be analyzed and measured, the straight-through valve at one end of the vent is closed, and the straight-through valve at one end of the gas chromatograph is opened for analysis and measurement.
Preferably, the front end of the gas chromatograph is connected with a filter, and the filter is filled with the allochroic silica gel drying and dehumidifying agent.
Preferably, the gas chromatograph is an Agilent GC990, and the carrier gas used for analysis is argon or helium.
The invention also provides a device for quantitatively measuring the generation amount of the coal low-temperature oxidation gas, which comprises O2Gas cylinder and N2Gas cylinder, O2Gas cylinder and N2All be connected with mass flow meter on the outer end pipeline of gas cylinder, mass flow meter's the other end is connected with the programming device through the three-way valve, the programming device includes coal sample jar and timing timer, still be connected with coal core temperature sensor on the coal sample jar, low temperature oxidation coal sample sets up in the coal sample jar, the other end of programming device also is connected with the tee bend pipeline, wherein one end is emptyd, the other end is connected with gas chromatograph through the filter, and all be connected with straight-through valve on two flow lines of gas products, gas chromatograph is connected with the computer, handle the analysis result of gas products through the computer.
Compared with the prior art, the invention has the following beneficial effects:
the invention controls the mass flow by introducing O into the coal sample tank in the temperature programming device2And N2And analyzing and measuring the flow, the components and the content of a gas product generated by low-temperature coal oxidation in a certain time period or a certain temperature period by using a gas chromatograph, further calculating the mass yield corresponding to each component of the gas product, and realizing the quantitative analysis of the gas generation amount in the low-temperature coal oxidation process. Compared with the current coal low-temperature oxidation research which can only explore the change situation of the gas concentration of each component along with the temperature in the low-temperature oxidation process and can only obtain the change trend of the gas, the method can quickly determine the low-temperature coalThe specific gas yield generated in the oxidation process is convenient for guiding the basic research of the low-temperature oxidation and spontaneous combustion mechanism of the coal.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
FIG. 1 is a schematic structural diagram of an apparatus for quantitatively determining the amount of coal low-temperature oxidizing gas generated according to the present invention;
FIG. 2 is a graph showing the change of the concentration of each component gas with temperature in the coal temperature-rising oxidation process in example 1 of the present invention;
FIG. 3 is a graph of the change of the mass flow of each component gas with time in the process of temperature rise and oxidation of coal in example 1 of the present invention;
FIG. 4 is a graph showing the change of the gas concentration of each component of the coal in the constant temperature oxidation process according to the embodiment 2 of the present invention with the oxidation time;
FIG. 5 is a graph showing the change of the gas mass flow of each component in the 120 ℃ constant temperature oxidation process of coal according to the embodiment of the invention with time.
The symbols in the drawings are marked as follows:
1.O2a gas cylinder; 2.N2A gas cylinder; 3. a mass flow meter; 4. a three-way valve; 5. a timing timer; 6. a coal core temperature sensor; 7. a coal sample tank; 8. oxidizing the coal sample at low temperature; 9. a straight-through valve; 10. a filter; 11. a gas chromatograph; and 12, a computer.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
Referring to FIG. 1, the present invention provides a device for quantitatively determining the amount of coal low-temperature oxidation gas generated, comprising O2Gas cylinders 1 and N2Gas cylinder 2, O2Gas cylinders 1 and N2All be connected with mass flow meter 3 on the outer end pipeline of gas cylinder 2, mass flow meter 3's the other end is connected with the program heating device through three-way valve 4, and the program heating device includes coal sample jar 7 and timing timer 5, still is connected with coal core temperature sensor 6 on the coal sample jar 7, and it can control rate of rise of temperature.
In the embodiment, the low-temperature oxidation coal sample 8 is arranged in the coal sample tank 7, the other end of the temperature programming device is also connected with a three-way pipeline, one end of the three-way pipeline is emptied, the other end of the three-way pipeline is connected with a gas chromatograph 11 through a filter 10, and two flow pipelines of a gas product are both connected with a straight-through valve 9; respectively carrying out continuous analysis and measurement on gas products in a certain time period and a certain temperature period through a timing timer 5 and a coal core temperature sensor 6 in a temperature programming device; the gas chromatograph 11 is connected to a computer 12, and the analysis result of the gas product is processed by the computer 12.
Furthermore, in this embodiment, the filter 10 is filled with the allochroic silica gel drying and dehumidifying agent, and needs to be replaced periodically.
Aiming at the problems that the existing coal low-temperature oxidation experiment can only carry out qualitative and semi-quantitative analysis on gas products, can only obtain the change trend of the gas, and can not carry out quantitative analysis on the gas products, the invention also provides an analysis method for quantitatively determining the generation amount of the coal low-temperature oxidation gas by using the device, and the analysis method uses N2And as the tracer gas, the specific gas generation amount in a certain time period or a certain temperature period in the low-temperature oxidation process of the coal is obtained by quantifying the gas product.
Example 1:
the analysis method is used for quantitatively measuring the generation amount of each component of a gas product in the temperature rise process of a coal low-temperature oxidation experiment (30-200 ℃), and comprises the following steps:
1) selecting a coal sample, stripping an oxide layer on the surface of the coal sample, crushing, and screening coal powder with the particle size of 40-80 meshes for later use.
2) Taking 50g of screened coal powder sample, filling the coal powder sample into a coal sample tank 7 for later use, laying a layer of thin asbestos on the upper part of the coal powder sample, then screwing a coal sample cover, and checking the air tightness of the coal sample tank 7.
3) And placing the coal sample tank 7 in a programmed heating furnace, wherein the left end opening of the programmed heating furnace is an air inlet opening, and the right end opening of the programmed heating furnace is a coal sample oxidizing gas outlet.
Regulating the final temperature rise temperature by a temperature programming device, wherein the temperature rise rate is 1 ℃/min, and the final oxidation temperature is 200 ℃; when the experiment is not started, the three-way valve 4 and the two straight-through valves 9 are both in a closed state, and when the temperature rise is started, the straight-through valve 9 at the emptying end is opened and the starting time is recorded.
4) Opening the three-way valve 4 while raising the temperature, and starting to introduce a certain proportion of O into the coal sample tank 72And N2In which O is2And N2The volume flow rates are 31.5ml/min and 118.5ml/min, respectively, so that the coal sample in the coal sample tank 7 starts to be slowly oxidized to generate oxidizing gas.
5) Gas products generated by low-temperature oxidation of coal enter a tee joint, one end of the gas products is discharged, and the other end of the gas products enters a gas chromatograph 11 through a filter 10; in the initial temperature raising stage, the straight-through valve 9 at the emptying end is opened, and the gas products generated by low-temperature oxidation of coal are continuously emptied.
In this embodiment, the gas chromatograph 11 is agilent GC990, and the carrier gas is argon or helium.
6) After the temperature of the coal sample tank 7 is raised to 30 ℃, the straight-through valve 9 at the emptying end is closed, the straight-through valve 9 at one end of the gas chromatograph 11 is opened, the gas product generated by oxidation is continuously introduced into the gas chromatograph 11 for analysis and measurement, and the analysis and measurement are carried out once at the temperature of 10 ℃ per liter until the temperature is raised to 200 ℃.
The qualitative analysis obtains the curve of the gas concentration of each component of the coal heating oxidation process along with the temperature change, as shown in figure 2.
7) Quantitatively analyzing each component gas in the coal temperature-rising oxidation process through a formula (1) and known N2Calculating the mass flow corresponding to each component of the gas product by using the volume flow:
in the formula, MiIs the mass flow rate corresponding to each component of the gas product; xiIs the mole fraction of the gas species measured by a gas chromatograph; xN2Is N2The mole fraction of (c); vN2Is N in the gas sample2The volume flow of the nitrogen is inert gas and does not participate in the whole oxidation reaction process, so the volume flow of the nitrogen in the gas sample is equal to the volume flow of the inlet of the coal sample tank; rhoiIs the density of the gas species at standard temperature and pressure.
The concentration of each gas component, X, determined by Agilent GC990 gas chromatographyiAnd XN2The concentrations in the analyzed products were% and ppm, respectively, ppm being one part per million, 0.0001%. In the analysis gas, Xi/XN2The ratio of the mole fractions is equivalent to the gas components of the gas product and the tracer gas N2The ratio of the concentrations of (a) to (b), before calculation, needs to be consistent for unit conversion; vN2Equal to the volume flow at the inlet of the coal sample tank, and in the present invention, 118.5 ml/min.
In this example, the densities of the individual gas components of the gas product at standard temperature and pressure (298K, 101.3KPa) are given in tables 1-1 below.
TABLE 1-1 Density of the gaseous product Components at Standard temperature and pressure
And (3) calculating the mass flow of each component gas at each time according to the method and the formula (1). FIG. 3 is a graph showing the change of the mass flow of each component gas with time during the whole temperature raising process in this example.
8) The mass yields corresponding to the individual components of the gaseous product were calculated.
The mass flow rate of each component gas calculated according to the formula (1) and the mass yield of each component gas in the temperature-rising oxidation process of the embodiment are calculated according to the formula (2):
in the formula, YiMass yields for the components of the gaseous product; t is the low temperature oxidation time.
In this embodiment, the mass yield of each component gas is integrated with respect to a time-varying curve of the mass flow rate of each component gas, that is, the area enclosed by the curve and the time axis, the mass flow rate MiThe unit of (2) is g/min, and the unit of time is min.
The mass yields of the component gases obtained in this example are shown in tables 1-2.
Tables 1-2 Mass yields of the component gases of this example throughout the temperature ramp
Example 2:
the analysis method is used for quantitatively measuring the generation amount of each component of the gas product in the coal low-temperature oxidation experiment at a constant temperature (120 ℃). The analysis method comprises the following steps:
1) selecting a coal sample, stripping an oxide layer on the surface of the coal sample, crushing, and screening coal powder with the particle size of 40-80 meshes for later use.
2) Taking 50g of screened coal powder sample, filling the coal powder sample into a coal sample tank 7 for later use, laying a layer of thin asbestos on the upper part of the coal powder sample, then screwing a coal sample cover, and checking the air tightness of the coal sample tank 7.
3) And placing the coal sample tank 7 in a programmed heating furnace, wherein the left end opening of the programmed heating furnace is an air inlet opening, and the right end opening of the programmed heating furnace is a coal sample oxidizing gas outlet.
Regulating the final temperature rise temperature by a temperature programming device, wherein the temperature rise rate is 1 ℃/min; when the experiment is not started, the three-way valve 4 and the two straight-through valves 9 are both in a closed state, and when the temperature rise is started, the straight-through valve 9 at the emptying end is opened and the starting time is recorded.
4) While the temperature is raised, the three-way valve 4 is opened and the coal supply is startedA certain proportion of O is introduced into the sample tank 72And N2In which O is2And N2The volume flow rates are 31.5ml/min and 118.5ml/min, respectively, so that the coal sample in the coal sample tank 7 starts to be slowly oxidized to generate oxidizing gas.
5) In the temperature rising stage, the straight-through valve 9 at one end of the vent is opened, and the gas product generated by low-temperature oxidation of the coal is continuously vented.
In this embodiment, the gas chromatograph 11 is agilent GC990, and the carrier gas is argon or helium.
6) And when the temperature of the coal sample tank 7 is raised to 120 ℃, closing the through valve 9 at the emptying end, opening the through valve 9 at one end of the gas chromatograph 11, continuously introducing the gas product generated by oxidation into the gas chromatograph 11 for analysis and determination, and keeping the constant temperature state of 120 ℃ for 120 min.
In this example, qualitative analysis was performed to obtain the component gases (CO, CO) in the coal constant temperature oxidation process2、CH4) The concentration is plotted as a function of oxidation time, as shown in FIG. 4.
7) Quantitatively analyzing each component gas in the coal 120 ℃ constant temperature oxidation process through a formula (1) and known N2Calculating the mass flow corresponding to each component of the gas product by using the volume flow:
in the formula, MiIs the mass flow rate corresponding to each component of the gas product; xiIs the mole fraction of the gas species measured by a gas chromatograph; xN2Is N2The mole fraction of (c); vN2Is N in the gas sample2The volume flow of the nitrogen is inert gas and does not participate in the whole oxidation reaction process, so the volume flow of the nitrogen in the gas sample is equal to the volume flow of the inlet of the coal sample tank; rhoiIs the density of the gas species at standard temperature and pressure.
The concentration of each gas component, X, determined by Agilent GC990 gas chromatographyiAnd XN2The concentrations in the analyzed products were% and ppm, respectivelyPpm is 0.0001% parts per million. In the analysis gas, Xi/XN2The ratio of the mole fractions is equivalent to the gas components of the gas product and the tracer gas N2The ratio of the concentrations of (a) to (b), before calculation, needs to be consistent for unit conversion; vN2Equal to the volume flow at the inlet of the coal sample tank, and in the present invention, 118.5 ml/min.
In this example, the density of the individual gas components of the gas product at standard temperature and pressure (298K, 101.3KPa) is as follows: the density of CO is 1.1605X 10-3g/cm3；CO2Has a density of 1.8323 x 10-3g/cm3；CH4Has a density of 0.66562 x 10-3g/cm3。
And (3) calculating the mass flow of each component gas at each time according to the method and the formula (1).
FIG. 5 is a graph showing the change of the gas mass flow of each component with time during the whole constant temperature process of 120 ℃ in the present example.
8) The mass yields corresponding to the individual components of the gaseous product were calculated.
The mass flow rate of each component gas calculated according to the formula (1) and the formula (2) calculate the mass yield of each component gas in the constant temperature oxidation process at 120 ℃ in the embodiment:
in the formula, YiMass yields for the components of the gaseous product; t is the low temperature oxidation time.
In this embodiment, the mass yield of each component gas is integrated with respect to a time-varying curve of the mass flow rate of each component gas, that is, the area enclosed by the curve and the time axis, the mass flow rate MiThe unit of (2) is g/min, and the unit of time is min.
In the embodiment, the CO and the CO of the coal low-temperature oxidation gas products are quantitatively calculated in the constant-temperature oxidation process at 120 DEG C2And CH4Mass yield of (3).
The mass yields of the component gases obtained in this example are shown in Table 2-1.
Table 2-1 mass yields of the component gases of this example throughout the temperature ramp
Further, in the present invention, the coal sample of the selected coal type may be long flame coal, gas coal, fat coal, coking coal, lean coal, or the like.
In the present invention, the concepts already mentioned have mainly the following meanings:
the gaseous products, i.e., the series of oxidizing gases produced during the low temperature oxidation of coal, generally include: CO, CO2、CH4、C2H4、C2H2、C2H6、C3H8。
A mass flow meter, an instrument for accurately measuring a gas flow rate, whose measurement value is not misaligned due to fluctuations in temperature or pressure, and does not require temperature-pressure compensation; it can control and directly measure instantaneous mass flow, volume flow, temperature, density and so on of medium, in the invention, the measurement O can be controlled by the mass flowmeter2And N2The volume flow rate of (a).
The gas chromatography is a separation and analysis method with high analysis speed and high separation efficiency, and is widely applied to industrial, agricultural, national defense and scientific research due to the advantages of high analysis sensitivity, wide application range and the like. The type of the gas chromatograph used in the invention is Agilent GC990, and the carrier gas used for analysis and determination is argon or helium.
ppm is a unit of concentration, in parts per million, equal to 0.0001%. For gases, ppm generally refers to mole fraction or volume fraction.
The analysis gas refers to the mixed gas which is introduced into the Agilent GC990 gas chromatograph and comprises N as the tracer gas2And gas products produced during low temperature oxidation of coal.
The invention is characterized in that the coal sample tank in the temperature programming device is filled with coalControlling mass flow rate of O2And N2And analyzing and measuring the flow, the components and the content of a gas product generated by low-temperature coal oxidation in a certain time period or a certain temperature period by using a gas chromatograph, further calculating the mass yield corresponding to each component of the gas product, and realizing the quantitative analysis of the gas generation amount in the low-temperature coal oxidation process. Compared with the current coal low-temperature oxidation research which only can explore the change situation of the gas concentration of each component along with the temperature in the low-temperature oxidation process and only can obtain the change trend of the gas, the method can quickly measure the specific gas yield generated in the coal low-temperature oxidation process, and is convenient for guiding the basic research of the coal low-temperature oxidation and coal spontaneous combustion mechanism.
Furthermore, the present invention is not limited to the prior art, and will not be described herein.
In the description of the present invention, it is to be understood that the orientations or positional relationships indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like are based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and for simplicity of description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present application.
Further, in the description of the present application, "a plurality" means two or more unless specifically defined otherwise.
The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (10)
1. An analysis method capable of quantitatively measuring the generation amount of coal low-temperature oxidation gas is characterized by comprising the following steps:
1) selecting a coal sample of coal species, stripping an oxide layer on the surface of the coal sample, crushing, and screening coal dust with the particle size of 40-80 meshes for later use;
2) taking 50g of screened coal dust sample, and filling the coal dust sample into a coal sample tank for later use;
3) placing the coal sample tank in a temperature programming device, and heating at a stable heating rate;
4) heating while introducing gas O2And N2Introducing the coal sample into a reactor together according to a certain proportion, so that the coal sample in the coal sample tank begins to be slowly oxidized to generate oxidizing gas;
5) gas products generated by low-temperature oxidation of coal enter a tee joint, one end of the gas products is discharged to the air, the other end of the gas products enters a gas chromatograph through a filter, and when the gas products generated by low-temperature oxidation of coal do not need to be analyzed and measured, a straight-through valve at the empty end is opened for continuous emptying;
6) closing the straight-through valve at the emptying end, opening the straight-through valve at one end of the gas chromatograph, and continuously introducing a gas product generated by oxidation into the gas chromatograph for analysis and determination;
7) the quantity of the oxidizing gas product is determined by the reaction with the known N2Comparing the volume flow and calculating the mass flow corresponding to each component of the gas product;
8) the mass yields corresponding to the individual components of the gaseous product were calculated.
2. The analytical method for quantitatively determining the amount of coal low-temperature oxidizing gas generated according to claim 1, wherein the mass flow of each component of the gas product is calculated by the following formula:
in the formula, MiIs the mass flow rate corresponding to each component of the gas product; xiIs the mole fraction of a gas species measured by a gas chromatograph; xN2Is N2The mole fraction of (c); vN2Is N in the gas sample2Because the nitrogen is inert gas and does not participate in the whole oxidation reaction process, the volume flow of the nitrogen is equal to that of the coal sample tank inlet in the gas sampleThe volume flow rate; rhoiIs the density of the gas species at standard temperature and pressure.
3. The analytical method for quantitatively determining the amount of coal low-temperature oxidation gas generated according to claim 2, wherein the mass yield of each component of the gas product is calculated according to the following formula:
Yi＝∫0 tMidt
in the formula, YiMass yields for the components of the gaseous product; t is the low temperature oxidation time.
4. The analytical method according to claim 1 or 3, wherein the pulverized coal sample is charged into the coal sample tank in step 2), a thin asbestos layer is laid on top of the pulverized coal sample, then the coal sample cover is tightened, and the airtightness of the coal sample tank is checked.
5. The analytical method capable of quantitatively determining the amount of coal low-temperature oxidizing gas generated according to claim 4, wherein in step 3), the coal sample tank is installed in a temperature programmed furnace, and the left end opening of the temperature programmed furnace is an air inlet opening and the right end opening of the temperature programmed furnace is a coal sample oxidizing gas outlet; the temperature programming furnace is connected with a coal core temperature sensor, and the temperature programming device is also provided with a timing timer.
6. The method according to claim 5, wherein O is added in step 4)2、N2Act as oxidizing gas and tracer gas respectively, and by mass flow meter control gas flow to mass flow meter's rear end is connected with the three-way valve.
7. The analytical method according to claim 6, wherein in steps 5) and 6), a through valve is connected to both flow paths of the gas product, and when the gas product is not required to be analyzed, the through valve at the vent end is opened, and the through valve at the gas chromatograph end is closed to continue venting; when the gas product is to be analyzed and measured, the straight-through valve at one end of the vent is closed, and the straight-through valve at one end of the gas chromatograph is opened for analysis and measurement.
8. The analytical method capable of quantitatively determining the amount of coal low-temperature oxidation gas generated according to claim 1 or 7, wherein a filter is connected to the front end of the gas chromatograph, and the filter is filled with a allochroic silica gel drying and dehumidifying agent.
9. The analytical method capable of quantitatively determining the generation amount of the coal low-temperature oxidation gas as claimed in claim 8, wherein the gas chromatograph is an Agilent GC990, and the carrier gas used for the analytical determination is argon or helium.
10. A device for quantitatively measuring the generation amount of coal low-temperature oxidizing gas is characterized by comprising O2Gas cylinder and N2Gas cylinder, O2Gas cylinder and N2The device comprises a gas cylinder, a mass flow meter, a programmed temperature device, a three-way valve, a coal core temperature sensor, a low-temperature oxidation coal sample, a three-way pipeline, a gas chromatograph and a computer, wherein the mass flow meter is connected to pipelines at the outer end of the gas cylinder, the other end of the mass flow meter is connected with the programmed temperature device through the three-way valve, the programmed temperature device comprises a coal sample tank and a timing timer, the coal sample tank is further connected with the coal core temperature sensor, the low-temperature oxidation coal sample is arranged in the coal sample tank, the other end of the programmed temperature device is also connected with the three-way pipeline, one end of the programmed temperature device is emptied, the other end of the programmed temperature device is connected with the gas chromatograph through the filter, two flow lines of a gas product are connected with the straight-through valve, the gas chromatograph is connected with the computer, and an analysis result of the gas product is processed through the computer.
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| CN208818642U (en) * | 2018-09-07 | 2019-05-03 | 西安科技大学 | A kind of experimental system for testing coal spontaneous ignition overall process |
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| CN114935614A (en) * | 2022-05-24 | 2022-08-23 | 安徽理工大学 | Simulation experiment device and experiment method for analyzing reburning characteristics of coal body |
| CN114935614B (en) * | 2022-05-24 | 2024-02-23 | 安徽理工大学 | Simulation experiment device and method for analyzing coal afterburning characteristics |
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