Coal moisture infrared detection device and method

Abstract

The present invention relates to an infrared detection device and method for coal moisture. First, a sealed cavity and a sampling port that can be switched on and off are set, an inert gas is introduced, and a reference voltage value of the gas in the sealed cavity is determined by infrared detection at the sampling port connected to the outside world. Then, the sampling port is kept disconnected from the outside world, and a coal sample of known weight is heated to make the water vapor and the inert gas mix to reach an equilibrium state. The sampling port is opened to detect the response voltage value of the mixed gas; finally, based on the absorbance response value of the response voltage value and the reference voltage value, the water content of the coal sample is substituted into the fitting data model to obtain its moisture value. Compared with the traditional weighing method, the moisture value of the coal sample measured by this method is simpler to operate, does not require complicated weighing, recording and verification steps, has extremely high convenience, and has high test efficiency, can quickly obtain test results, and effectively saves time and labor costs.

Description

Technical Field

[0001] The invention relates to the field of online testing, and in particular to a coal moisture infrared detection device and method. Background Art

[0002] The moisture content in coal is an important indicator for evaluating its economic value. The more moisture content in coal, the more useless components in coal, which directly reduces the thermal efficiency of coal and leads to a decrease in its economic value. In addition, the moisture in coal has an adverse effect on the stable combustion of boilers, the stable operation of coal transportation systems, transportation and storage. Therefore, accurate measurement of the moisture content in coal is crucial for the reasonable evaluation of the economic value of coal. At present, there are few methods for determining the moisture content in coal. The existing technology generally refers to the two standard methods of "GB / T 211 Determination of Total Moisture in Coal" and "DL / T 2029 Automatic Instrument Method for Determination of Total Moisture in Coal", that is, the weight loss method and microwave method are used to determine the moisture content in coal. Among them, the microwave method has not been widely used due to its strict requirements on the type of coal, so the main method used is the weight loss method. The weight loss method obtains the moisture content by measuring the weight change of the sample before and after drying, but the weight loss method detection steps are cumbersome and time-consuming, and the detection process is limited by its principle, and the temperature control requirements are high. In addition, the material particles or volatile components precipitated during the test also have a certain interference with the test results. Therefore, a new and simple non-weighing method for coal moisture is provided to reduce the measuring devices and measuring methods in the testing process to solve the above problems. Summary of the invention

[0003] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a coal moisture infrared detection device and method, which solves the problem of long time and low efficiency in the coal moisture detection process of the prior art.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for infrared detection of coal moisture comprises the following steps:

[0006] Step S 1 , setting a sealed cavity and a sampling port that can be switched on and off, introducing an inert gas, and determining a reference voltage value of the gas in the sealed cavity by infrared detection at the sampling port connected to the outside;

[0007] Step S 2 1. Keep the sampling port isolated from the outside world, heat the coal sample in the sealed chamber, and mix the water vapor and the inert gas to reach an equilibrium state; open the sampling port, detect the response voltage value of the mixed gas through infrared, and the sample weight of the coal sample is known;

[0008] Step S 3, obtaining an absorbance response value of the coal sample based on the response voltage value and the reference voltage value;

[0009] Step S 4 , substituting the absorbance response value into the fitting data model to obtain the water content of the coal sample, and then obtaining the moisture value of the coal sample.

[0010] Furthermore, the step of building a fitting data model is also included:

[0011] Obtain a standard water sample of known mass, and record the mass as the water-containing mass; provide a sealed cavity and a sampling port that can be switched on and off, introduce an inert gas, and determine the reference voltage value of the gas in the sealed cavity by infrared detection at the sampling port connected to the outside world; keep the sampling port disconnected from the outside world, put the standard water sample into the sealed cavity for heating, and mix the water vapor and the inert gas to reach an equilibrium state; open the sampling port, detect the response voltage value of the mixed gas by infrared, and obtain the absorbance response value of the standard water sample based on the response voltage value and the reference voltage value;

[0012] Repeat the above steps at least 3 times to obtain the absorbance response values ​​of at least 3 groups of standard water samples;

[0013] Get the fitted data model , where: m w —water content, unit: mg; A—absorbance response value, unit: A. Substitute the absorbance response values ​​and water content of at least 3 groups of standard water samples into the fitting data model to determine k and b, and then determine the fitting data model.

[0014] Furthermore, the moisture value of the coal sample refers to the percentage of the water content in the coal sample to the weight of the sample, and the moisture value is calculated according to the following formula:

[0015]

[0016] In the formula: M—moisture value, unit: %

[0017] m—sample weight, unit: mg;

[0018] k and b are known, and A is the absorbance response value of the coal sample.

[0019] Furthermore, the absorbance response value is obtained based on the following formula:

[0020]

[0021] Where: A—absorbance response value, unit A;

[0022] V 0 —reference voltage value;

[0023] V 1 —Response voltage value.

[0024] Further, the step of mixing the water vapor and the inert gas to reach an equilibrium state comprises the following steps:

[0025] Step S 21 , introducing inert gas to mix with the water vapor released from the drying of the coal sample through spontaneous diffusion;

[0026] Step S 22 , determine whether the pressure in the sealing chamber reaches the set value;

[0027] If so, it is determined that the water vapor and the inert gas in the sealed cavity have reached an equilibrium state.

[0028] Furthermore, the step S 1 The following steps are involved:

[0029] Step S 11 , a sealed cavity, a sampling port and a pressure relief port which can be connected and disconnected with the sealed cavity are provided, the sampling port is connected to a moisture infrared detector, a pressure detector is provided at the pressure relief port and the entrance of the sealed cavity, the pressure relief port is closed, and an inert gas is introduced into the sealed cavity;

[0030] Step S 12 1. When the gas flow at the pressure relief port inlet monitored by the pressure detector is much greater than the gas flow through the sampling port, the pressure relief port and the moisture infrared detector are opened to discharge the mixed gas of the inert gas and the air containing impurity particles in the sealed cavity;

[0031] Step S 13 , detect the reference voltage value of the mixed gas through infrared at the sampling port;

[0032] Step S 14 , after the reference voltage value stabilizes, close the pressure relief port and sampling port.

[0033] In order to achieve the above object, the present invention also adopts the following technical solutions:

[0034] A coal moisture infrared detection device comprises a shell, a setting-out platform, a heating part and a moisture infrared detector;

[0035] The shell is surrounded to form a sealed cavity, and a sampling port and a pressure relief port communicating with the sealed cavity are provided on the top of the shell, and the sampling port and the pressure relief port are of on-off structure;

[0036] The lofting platform is located at the bottom of the sealed cavity;

[0037] The heating part is located on the lower surface of the sample setting platform and is used to dry the coal sample in the sample setting platform to separate water vapor;

[0038] The moisture infrared detector is arranged on the sampling port and is used to detect the reference voltage value and also used to detect the response voltage value when the coal sample is dry;

[0039] A pressure detector is provided at the inlet of the pressure relief port communicating with the sealed cavity, which is used to detect the gas flow at the inlet of the pressure relief port and also to detect the gas flow passing through the infrared detector;

[0040] An inert gas inlet connected to the sealed cavity is provided at the lower portion of the shell. The inert gas inlet is used to introduce inert gas into the sealed cavity to cooperate with the moisture infrared detector to detect the reference voltage value. It is also used to introduce inert gas into the sealed cavity when the coal sample is dried to mix with water vapor precipitated from the coal sample to reach an equilibrium state to cooperate with the moisture infrared detector to detect the response voltage value.

[0041] Furthermore, it also includes a pressure control module, which is arranged on the pressure relief port and is used to detect whether the gas in the sealed cavity is saturated and to monitor whether the inert gas and water vapor in the sealed cavity have reached a balanced state.

[0042] Furthermore, the layout platform also includes a connector for radially limiting the sealing cavity; the connector is abutted or fixedly connected to the shell.

[0043] Further, one end of the connecting member is fixedly connected to the inner surface of the top of the shell, and the other end is fixedly connected to the side wall of the lofting platform; and / or

[0044] The connecting piece is a protrusion extending horizontally from the side wall of the lofting platform and is used for abutting against the inner wall of the shell.

[0045] In summary, compared with the prior art, the present invention has at least the following beneficial effects:

[0046] The present invention designs a method for infrared detection of coal moisture, firstly, a sealed cavity and a sampling port that can be switched on and off are provided, an inert gas is introduced, and a reference voltage value of the gas in the sealed cavity is determined by infrared detection at the sampling port connected to the outside world, and then the sampling port is kept disconnected from the outside world, a coal sample of known weight is heated to make the water vapor and the inert gas mix to reach an equilibrium state, the sampling port is opened, and the response voltage value of the mixed gas is detected; finally, the absorbance response value based on the response voltage value and the reference voltage value is substituted into the fitting data model to obtain the water content of the coal sample and then obtain its moisture value. Compared with the traditional weighing method, the moisture value of the coal sample measured by this method is simpler to operate, does not require complicated weighing, recording and verification steps, has extremely high convenience, and has high test efficiency, can quickly obtain test results, and effectively saves time and labor costs.

[0047] The present invention also provides a coal moisture infrared detection device corresponding to the above-mentioned coal moisture infrared detection method, which has the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 The present invention provides a flow chart of the method for infrared detection of coal moisture.

[0050] Figure 2 It is a cross-sectional schematic diagram of a coal moisture infrared detection device provided in one embodiment of the present invention.

[0051] Description of reference numerals:

[0052] 1. Shell; 11. Sealed cavity; 12. Sampling port; 13. Pressure relief port; 14. Inert gas inlet; 15. End cover; 16. Body; 17. Cavity wall; 171. Extension section; 172. Sealing element; 18. Heat insulation layer;

[0053] 2. Lofting platform; 21. Connectors;

[0054] 3. Heating unit;

[0055] 4. Moisture infrared detector;

[0056] 5. Pressure control module. DETAILED DESCRIPTION

[0057] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0059] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] As attached Figure 1 As shown, a method for infrared detection of coal moisture comprises the following steps:

[0061] Step S 1 , a sealed cavity 11 and a sampling port 12 which can be switched on and off are provided, an inert gas is introduced, and a reference voltage value of the gas in the sealed cavity 11 is determined by infrared detection at the sampling port 12 which is connected to the outside.

[0062] Specifically, step S 1 The following steps are involved:

[0063] Step S 11 , a sealed cavity 11, a sampling port 12 and a pressure relief port 13 which can be connected and disconnected with the sealed cavity 11 are provided, the sampling port 12 is connected to the moisture infrared detector 4, a pressure detector is provided at the pressure relief port 13 and the entrance of the sealed cavity 11, the pressure relief port 13 is closed, the sampling port 12 is opened, and an inert gas is introduced into the sealed cavity 11;

[0064] Step S 12 When the gas flow rate of the pressure relief port 13 monitored by the pressure detector is much greater than the gas flow rate of the sampling port 12, the pressure relief port 13 and the moisture infrared detector 4 are opened to discharge the mixed gas of the inert gas and the air containing impurity particles in the sealed cavity 11;

[0065] Step S 13 , detecting the reference voltage value of the mixed gas by infrared at the sampling port 12;

[0066] Step S 14, after the reference voltage value stabilizes, close the pressure relief port 13 and the sampling port 12.

[0067] The flow rate of the inert gas is preferably 2 L / min.

[0068] Step S 2 , keep the sampling port 12 isolated from the outside, heat the coal sample in the sealed chamber 11, and mix the water vapor and the inert gas to reach an equilibrium state; open the sampling port 12, detect the response voltage value of the mixed gas through infrared, and the sample weight of the coal sample is known.

[0069] Among them, the equilibrium state means that all the moisture in the coal sample is precipitated and collected by the sealed cavity 11. It is the equilibrium state after the precipitated water vapor and the inert gas diffuse and mix spontaneously. The mixed gas at this time is representative, that is, the mixed gas subsequently flowing out from the sampling port 12 and detected by the moisture infrared detector 4 can represent the average state of the mixed gas in the entire sealed cavity 11, so that the final test result can truly reflect the moisture value of the coal sample.

[0070] More specifically, the process of mixing water vapor and an inert gas to reach an equilibrium state comprises the following steps:

[0071] Step S 21 , introducing inert gas to mix with the water vapor released from the drying of the coal sample through spontaneous diffusion;

[0072] Step S 22 , judging whether the pressure in the sealed cavity 11 reaches a set value through the pressure control module 5;

[0073] If yes, it is determined that the water vapor and the inert gas in the sealed cavity 11 have reached an equilibrium state, and the sampling port 12 can be opened to start the subsequent detection work of the moisture infrared detector 4 .

[0074] If not, it is determined that the water vapor and the inert gas in the sealed chamber 11 have not yet reached equilibrium. At this time, the coal sample should continue to be dried at a constant temperature so that all the moisture in the coal sample is precipitated, and at the same time, the inert gas should continue to be introduced to continue spontaneous diffusion and mixing with the water vapor precipitated from the coal.

[0075] Preferably, the set value is set to 0.2MPa±200pa.

[0076] In addition, the coal sample is flattened and placed on the sample placement platform 2 and placed in the sealed cavity 11 for heating. The weight of the coal sample tested each time is not less than 5 g.

[0077] Step S 3 , the absorbance response value of the coal sample is obtained based on the measured response voltage value and the reference voltage value.

[0078] Specifically, the absorbance response value is obtained based on the following formula:

[0079]

[0080] Where: A—absorbance response value, unit A;

[0081] V 0 —reference voltage value;

[0082] V 1 —Response voltage value.

[0083] Step S 4 , Substitute the absorbance response value into the fitting data model to obtain the water content of the coal sample, and then obtain the moisture value of the coal sample.

[0084] Specifically, the calculation process of this step can be carried out in the computer system software connected to the device, or it can be calculated manually. Before starting the calculation, the fitting data model should be constructed in advance by the least squares method, that is, the functional relationship between the water content and the absorbance response value should be established through the standard water sample, and finally the water content of the coal sample should be determined by the measured absorbance response value through the above functional relationship. Furthermore, the standard water sample can be ultrapure water, deionized water, etc. that meet the laboratory water requirements. The water content of the standard water sample is 100%, that is, the weight of the weighed standard water sample is the water content of the standard water sample.

[0085] Therefore, the detection method also includes the step of constructing a fitting data model:

[0086] Obtain a standard water sample of known mass, and record the mass as the water-containing mass; set a sealed cavity 11 and a sampling port 12 that can be switched on and off, introduce an inert gas, and determine the reference voltage value of the gas in the sealed cavity 11 through infrared detection at the sampling port 12 that is connected to the outside world; keep the sampling port 12 disconnected from the outside world, put the standard water sample into the sealed cavity 11 for heating, and mix the water vapor and the inert gas to reach an equilibrium state; open the sampling port 12, detect the response voltage value of the mixed gas through infrared, and obtain the absorbance response value of the standard water sample based on the response voltage value and the reference voltage value;

[0087] Repeat the above steps at least 3 times to obtain absorbance response values ​​of at least 3 groups of standard water samples. In particular, the more groups of standard water samples are obtained, the more accurate the subsequent fitting results will be.

[0088] Get the fitted data model , where: m w—Water content, unit: mg; A—Absorbance response value, unit: A. Substitute the absorbance response values ​​and water content of at least 3 groups of standard water samples into the fitting data model to determine k and b, and then determine the final fitting data model that can be used for coal samples.

[0089] It should be noted that the coal moisture infrared detection method provided by the present invention pre-builds a model that can be applied to all types of coal for moisture quality calculation, and has strong versatility. Alternatively, in order to meet different detection requirements or ensure the accuracy of the calculation results, the user can also choose to update the fitting data model every time or at intervals, and adjust and optimize according to actual conditions, which is not limited here.

[0090] Finally, since the moisture value of a coal sample refers to the percentage of water content in the coal sample to the weight of the sample, the moisture value must be calculated using the weight parameters of the coal sample according to the following formula:

[0091]

[0092] In the formula: M—moisture value, unit: %

[0093] m—sample weight, unit: mg;

[0094] k and b are known, and A is the absorbance response value of the coal sample.

[0095] Compared with the traditional weighing method, the moisture value of the coal sample measured by the above-mentioned coal moisture infrared detection method is simpler to operate and does not require complicated weighing, recording and verification steps. It is extremely convenient and has high testing efficiency. It can quickly obtain test results, effectively saving time and labor costs.

[0096] As attached Figure 2 As shown, in addition to the above-mentioned coal moisture infrared detection method, the present invention also provides a coal moisture infrared detection device based on the above-mentioned coal moisture infrared detection method. The coal moisture infrared detection device corresponds to the steps of the above-mentioned coal moisture infrared detection method. The coal moisture infrared detection device described below and the coal moisture infrared detection method described above can be referenced to each other.

[0097] A coal moisture infrared detection device comprises a housing 1, a setting out platform 2, a heating part 3 and a moisture infrared detector 4;

[0098] The housing 1 surrounds a sealed cavity 11. The top of the housing 1 is provided with a sampling port 12 and a pressure relief port 13 which are connected to the sealed cavity 11. The sampling port 12 and the pressure relief port 13 are of on-off structure.

[0099] The sample placement platform 2 is located at the bottom of the sealed cavity 11;

[0100] The heating part 3 is located on the lower surface of the sample setting platform 2 and is used to dry the coal sample in the sample setting platform 2 to separate water vapor;

[0101] The moisture infrared detector 4 is arranged on the sampling port 12 and is used to detect the reference voltage value and also used to detect the response voltage value when the coal sample is dry;

[0102] A pressure detector (not shown in the figure) is provided at the inlet of the pressure relief port 13 communicating with the sealed cavity 11, which is used to detect the gas flow at the inlet of the pressure relief port 13 and also to detect the gas flow passing through the moisture infrared detector 4;

[0103] An inert gas inlet 14 connected to the sealed cavity 11 is provided at the lower part of the shell 1, which is used to introduce inert gas into the sealed cavity 11 to cooperate with the moisture infrared detector 4 to detect the reference voltage value. It is also used to introduce inert gas when the coal sample is dried to mix with the water vapor precipitated from the coal sample to reach an equilibrium state to cooperate with the moisture infrared detector 4 to detect the response voltage value.

[0104] Specifically, the shell 1 surrounds a sealed cavity 11 that can provide an environment for coal sample detection. The sealed cavity 11 can provide a stable environment for detection. The sampling port 12 and the pressure relief port 13 connected to the sealed cavity 11 can realize intelligent control of the outflow of gas in the sealed cavity 11, and can determine whether to allow the gas in the sealed cavity 11 to flow out from the sampling port 12 or the pressure relief port 13 according to a specific detection step. The reason why the lofting platform 2, the heating part 3 and the inert gas inlet 14 are all arranged at the lower part of the sealed cavity 11 is that after the water vapor and the inert gas are mixed and before entering the moisture infrared detector 4 arranged above, a certain space can be provided for the process of the two mixing and entering the equilibrium state, so as to prevent the uneven distribution of water vapor and the inert gas after entering the sealed cavity 11, resulting in excessively high or low local concentration of water vapor in the sealed cavity 11, affecting the detection stability and accuracy. Compared with the traditional device based on the weighing method, the present device has a simple structure and is simpler to operate, so that it can be detected without professional detection personnel. General experimental personnel can master the coal moisture infrared detection method after simple training, which improves the operability and popularity of the detection. In addition, due to the simple operation steps, the test efficiency is high and the test results can be obtained quickly, effectively saving time and labor costs.

[0105] Furthermore, the heating unit 3 may be a constant temperature heating device such as a constant temperature heating plate or a constant temperature heating wire, which is not limited here. In addition, the inert gas may be a gas such as nitrogen or helium, which is not limited here.

[0106] In one embodiment of the present invention, in order to detect whether the gas in the sealed chamber 11 is saturated during the early determination of the reference voltage, or to monitor whether the inert gas and water vapor in the sealed chamber 11 reach a state of equilibrium when the moisture value of the coal sample is detected, the device is also provided with a pressure control module 5 on the pressure relief port 13, which further helps to improve the accuracy and reliability of the coal moisture detection device. Specifically, when the end of the drying and water separation process is about to be reached, the pressure control module 5 can be used to determine whether the state of the mixed gas in the sealed chamber 11 is stable at this time. If it is stable, it means that the drying and water separation process of the coal sample has been fully carried out, and the mixed gas composed of the inert gas and water vapor has reached a state of equilibrium and has been mixed evenly, thereby ensuring that part of the mixed gas flowing out of the sampling port 12 is representative of the mixed gas collected in the sealed chamber 11, that is, the mixed gas flowing out of the sampling port 12 can represent the average state of the mixed gas in the entire sealed chamber 11, so that the detection result can truly reflect the moisture value of the coal sample. In addition, when the pressure in the sealed chamber 11 increases abnormally, the pressure control module 5 can detect the abnormal pressure change in time. If the pressure exceeds a certain safety value, the pressure control module 5 will automatically open the pressure relief port 13 to release part of the pressure to avoid strength failure of the sealed chamber 11 due to excessive pressure, thereby protecting the sealed chamber 11.

[0107] In one embodiment of the present invention, the sample setting platform 2 also includes a connector 21 for radially limiting the sealing chamber 11. The limiting function of the connector 21 can ensure that the sample setting platform 2 is located at the center of the heating part 3 during each test, so as to avoid uneven heating due to position changes during a certain test, which affects the efficiency and consistency of water analysis. At the same time, the moisture infrared detector 4 and the coal sample on the sample setting platform 2 can maintain a fixed relative position during each test, thereby improving the consistency of the test, helping to establish a unified test standard when multiple batches of coal samples need to be compared, facilitating the comparison of different test results, and facilitating the establishment of a standardized test process. The connecting piece 21 can be selected to abut or fixedly connected with the shell 1. Specifically, the connecting piece 21 can be selected to be fixedly connected with the top inner surface of the shell 1 at one end. By increasing the fitting portion with the top inner surface of the shell 1, the stability of the connection can be significantly improved. The fitting portion should be provided with a portion connected to the sampling port 12 and the pressure relief port 13 to ensure the normal operation of the device. The other end is fixedly connected to the side wall of the sample laying platform 2. The connecting piece 21 as a whole can be made of hard materials such as stainless steel to prevent the connecting piece 21 from deforming and causing the position of the sample laying platform 2 to change in the sealed chamber 11; and / or the connecting piece 21 is a protrusion extending horizontally from the side wall of the sample laying platform 2, which is used for abutting with the inner wall of the shell 1 and other fixing methods. Different fixing methods have no effect on the results of experimental detection. Users can choose according to actual usage requirements such as convenience, stability and other factors, which are not limited here.

[0108] In one embodiment of the present invention, the housing 1 includes an end cover 15 at the top, a body 16 sealed with the end cover 15, and a cavity wall 17 arranged inside the side wall of the body 16. The top periphery of the body 16 is provided with a plurality of protrusions, and the end cover 15 is provided with a plurality of limiting through holes that cooperate with the protrusions; after the protrusions are aligned with the limiting through holes, the protrusions are engaged with the limiting through holes by screwing the end cover 15 to seal the housing 1. At this time, the sealed cavity 11 is surrounded by the end cover 15, the cavity wall 17 and the bottom of the body 16. An extension section 171 is vertically provided at the cavity wall 17 abutting the end cover 15, and a groove is provided on the upper surface of the extension section 171 for placing a sealing member 172 to further enhance the sealing effect. Preferably, the sealing member 172 is a sealing ring.

[0109] In one embodiment of the present invention, a heat insulating layer 18 is provided between the inner surface of the body 16 and the outer surface of the cavity wall 17. The heat insulating layer 18 has a heat storage function to prevent the temperature in the sealed cavity 11 from being affected by the external low temperature and lowering, which causes the water vapor to condense on the cavity wall 17 and other parts during the process of heating the coal sample to precipitate water vapor, thereby affecting the accuracy of moisture detection.

[0110] The present invention is further described in detail below in conjunction with embodiments.

[0111] Example 1 - Pre-construction of fitting data model:

[0112] (1) Standard water sample w 1 :Put 4.5 mg of standard water sample into a φ200 mm, 15 mm deep sample platform, and record 4.5 mg as the water content m w ; Close the sampling port and the pressure relief port, open the inert gas inlet, and introduce nitrogen into the sealed chamber at 2L / min; when the gas flow rate monitored by the pressure control module is much greater than the gas flow rate monitored by the moisture infrared detector, open the pressure relief port and the sampling port to discharge the mixed gas of the inert gas and the air containing impurity particles in the sealed chamber; detect the reference voltage value V of the mixed gas through infrared detection at the sampling port 0 is 8.5404; after the reference voltage value is stable, close the pressure relief port and the sampling port; move the sample placement platform into the sealed cavity, and seal the end cover and the body together to keep the sampling port isolated from the outside world, turn on the heating unit, keep the temperature constant at 107°C to heat the standard water sample in the sealed cavity, turn on the inert gas inlet, read the pressure in the sealed cavity as 0.2MPa through the pressure control module, open the sampling port, and detect the response voltage value V of the mixed gas through the moisture infrared detector 1 is 7.4918; through the formula of absorbance response value The absorbance response value of the standard water sample is calculated to be A=0.131A;

[0113] (2) Standard water sample w 2:Put 6.6 mg of standard water sample into a φ200 mm, 15 mm deep sample platform, and record 6.6 mg as the water content m w ; Close the sampling port and the pressure relief port, open the inert gas inlet, and introduce nitrogen into the sealed chamber at 2L / min; when the gas flow rate monitored by the pressure control module is much greater than the gas flow rate monitored by the moisture infrared detector, open the pressure relief port and the sampling port to discharge the mixed gas of the inert gas and the air containing impurity particles in the sealed chamber; detect the reference voltage value V of the mixed gas through infrared detection at the sampling port 0 is 8.5413; after the reference voltage value is stable, close the pressure relief port and the sampling port; move the sample placement platform into the sealed cavity, and seal the end cover and the body together to keep the sampling port isolated from the outside world, turn on the heating unit, keep the temperature constant at 107°C to heat the standard water sample in the sealed cavity, turn on the inert gas inlet, read the pressure in the sealed cavity as 0.2MPa through the pressure control module, open the sampling port, and detect the response voltage value V of the mixed gas through the moisture infrared detector 1 is 7.1693; through the formula of absorbance response value The absorbance response value of the standard water sample is calculated to be A=0.1751A;

[0114] (3) Standard water sample w 3 :Put 8.3 mg of standard water sample into a φ200 mm, 15 mm deep sample platform, and record 8.3 mg as the water content m w ; Close the sampling port and the pressure relief port, open the inert gas inlet, and introduce nitrogen into the sealed chamber at 2L / min; when the gas flow rate monitored by the pressure control module is much greater than the gas flow rate monitored by the moisture infrared detector, open the pressure relief port and the sampling port to discharge the mixed gas of the inert gas and the air containing impurity particles in the sealed chamber; detect the reference voltage value V of the mixed gas through infrared detection at the sampling port 0 is 8.5417; after the reference voltage value is stable, close the pressure relief port and the sampling port; move the sample placement platform into the sealed cavity, and seal the end cover and the body together to keep the sampling port isolated from the outside world, turn on the heating unit, keep the temperature constant at 107°C to heat the standard water sample in the sealed cavity, open the inert gas inlet, read the pressure in the sealed cavity as 0.2MPa through the pressure control module, open the sampling port, and detect the response voltage value V of the mixed gas through the moisture infrared detector 1 is 6.9453; through the formula of absorbance response value The absorbance response value of the standard water sample is calculated to be A=0.2069A;

[0115] (4) Standard water sample w 4 :Put 9.9 mg of standard water sample into a φ200 mm, 15 mm deep sample platform, and record 9.9 mg as the water content mw ; Close the sampling port and the pressure relief port, open the inert gas inlet, and introduce nitrogen into the sealed chamber at 2L / min; when the gas flow rate monitored by the pressure control module is much greater than the gas flow rate monitored by the moisture infrared detector, open the pressure relief port and the sampling port to discharge the mixed gas of the inert gas and the air containing impurity particles in the sealed chamber; detect the reference voltage value V of the mixed gas through infrared detection at the sampling port 0 is 8.5418; after the reference voltage value is stable, close the pressure relief port and the sampling port; move the sample placement platform into the sealed cavity, and seal the end cover and the body together to keep the sampling port isolated from the outside world, turn on the heating unit, keep the temperature constant at 107°C to heat the standard water sample in the sealed cavity, turn on the inert gas inlet, read the pressure in the sealed cavity as 0.2MPa through the pressure control module, open the sampling port, and detect the response voltage value V of the mixed gas through the moisture infrared detector 1 is 6.7441; through the formula of absorbance response value The absorbance response value of the standard water sample is calculated to be A=0.2363A;

[0116] Get the fitted data model , where: m w —water content, unit: mg; A—absorbance response value, unit: A. Substitute the absorbance response values ​​and water content of the above four groups of standard water samples into the fitting data model, determine k=51.31 and b= -2.2866, and then determine the fitting data model m w =51.31×A-2.2866, where R=0.9988, which is considered to be a good linearity.

[0117] Example 2 - Detection of moisture content of coal sample 07L:

[0118] Step S 1 1. Close the sampling port and the pressure relief port, open the inlet of the inert gas, and introduce nitrogen into the sealed cavity at a rate of 2L / min; when the gas flow rate monitored by the pressure control module is much greater than the gas flow rate monitored by the moisture infrared detector, open the pressure relief port and the sampling port to discharge the mixed gas of the inert gas and the air containing impurity particles in the sealed cavity; detect the reference voltage value of the mixed gas at the sampling port by infrared detection of 8.5416; close the pressure relief port and the sampling port after the reference voltage value stabilizes;

[0119] Step S 2, flatten 80.1mg of the sample powder to be tested and load it into a φ200mm deep 15mm sample placement platform. Move the sample placement platform into the sealed cavity, and seal the end cover and the body, keep the sampling port isolated from the outside, turn on the heating part, keep the temperature constant at 107℃ to heat the coal sample in the sealed cavity, turn on the inert gas inlet, read the pressure in the sealed cavity as 0.2MPa through the pressure control module, open the sampling port, and detect the response voltage value of the mixed gas through the moisture infrared detector to be 7.6030;

[0120] Step S 3 , based on the response voltage value of 7.6030 and the reference voltage value of 8.5416, the absorbance response value of the coal sample is 0.1164A;

[0121] Step S 4 , Substitute the absorbance response value 0.1164A into the fitting data model m w =51.31×A-2.2866, the water content of the coal sample is m w is 3.68 mg, m w =3.68mg and m=80.1mg are substituted into the moisture value calculation formula M=m w / m×100%, the moisture value of the coal sample is 4.59%.

[0122] Example 3 - Detection of moisture content of coal sample 01s:

[0123] Step S 1 1. Close the sampling port and the pressure relief port, open the inlet of the inert gas, and introduce nitrogen into the sealed cavity at a rate of 2L / min; when the gas flow rate monitored by the pressure control module is much greater than the gas flow rate monitored by the moisture infrared detector, open the pressure relief port and the sampling port to discharge the mixed gas of the inert gas and the air containing impurity particles in the sealed cavity; detect the reference voltage value of the mixed gas at the sampling port by infrared detection of 8.5411; close the pressure relief port and the sampling port after the reference voltage value stabilizes;

[0124] Step S 2 , flatten 80.2mg of the sample powder to be tested and load it into a φ200mm deep 15mm sample placement platform. Move the sample placement platform into the sealed cavity, and seal the end cover and the body, keep the sampling port isolated from the outside, turn on the heating part, keep the temperature constant at 107℃ to heat the coal sample in the sealed cavity, turn on the inert gas inlet, read the pressure in the sealed cavity as 0.2MPa through the pressure control module, open the sampling port, and detect the response voltage value of the mixed gas through the moisture infrared detector to be 7.5904;

[0125] Step S 3, based on the response voltage value of 7.5904 and the reference voltage value of 8.5411, the absorbance response value of the coal sample is 0.1180A;

[0126] Step S 4 , Substitute the absorbance response value 0.1180A into the fitting data model m w =51.31×A-2.2866, the water content of the coal sample is m w is 3.77 mg, m w =3.77mg and m=80.2mg are substituted into the moisture value calculation formula M=m w / m×100%, the moisture value of the coal sample is 4.70%.

[0127] Table 1

[0128] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A method for infrared detection of coal moisture, characterized in that: The following steps are involved: Step S1, setting a sealed cavity and a sampling port that can be switched on and off, introducing an inert gas, and determining a reference voltage value of the gas in the sealed cavity by infrared detection at the sampling port connected to the outside; Step S2, keeping the sampling port isolated from the outside, heating the coal sample in the sealed chamber, and mixing the water vapor and the inert gas to reach an equilibrium state; opening the sampling port, detecting the response voltage value of the mixed gas by infrared, and the sample weight of the coal sample is known; Step S3: Based on the response voltage value and the reference voltage value, Obtain the absorbance response value of the coal sample, where: A—absorbance response value, unit A, V0—reference voltage value, V1—response voltage value; Step S4: Substitute the absorbance response value into the fitting data model to obtain the water content of the coal sample according to the formula M=m w / m*100% calculates the percentage of water content in the coal sample to the sample weight, where: M—water value, unit: %, m w —Water content, in mg, m—Sample weight, in mg, and then the moisture value of the coal sample is obtained; The construction of the fitting data model includes the following steps: obtaining a standard water sample of known mass, and recording the mass as the water-containing mass; setting a sealed cavity and a sampling port that can be switched on and off, introducing an inert gas, and determining the reference voltage value of the gas in the sealed cavity by infrared detection at the sampling port connected to the outside world; keeping the sampling port disconnected from the outside world, placing the standard water sample in the sealed cavity for heating, and mixing the water vapor and the inert gas to reach an equilibrium state; opening the sampling port, detecting the response voltage value of the mixed gas by infrared, and obtaining the absorbance response value of the standard water sample based on the response voltage value and the reference voltage value; repeating the above steps at least 3 times to obtain the absorbance response values ​​of at least 3 groups of standard water samples; Get the fitted data model , where: m w —water content, unit: mg; A—absorbance response value, unit: A. Substitute the absorbance response values ​​and water content of at least 3 groups of standard water samples into the fitting data model to determine k and b, and then determine the fitting data model.

2. The method for infrared detection of coal moisture according to claim 1, characterized in that: The step of mixing water vapor and inert gas to reach an equilibrium state comprises the following steps: Step S 21 , introducing inert gas to mix with the water vapor released from the drying of the coal sample through spontaneous diffusion; Step S 22 , determine whether the pressure in the sealing chamber reaches the set value; If so, it is determined that the water vapor and the inert gas in the sealed cavity have reached an equilibrium state.

3. The method for infrared detection of coal moisture as claimed in claim 1, characterized in that: The step S1 comprises the following steps: Step S 11 , a sealed cavity, a sampling port and a pressure relief port which can be connected and disconnected with the sealed cavity are provided, the sampling port is connected to a moisture infrared detector, a pressure detector is provided at the pressure relief port and the entrance of the sealed cavity, the pressure relief port is closed, and an inert gas is introduced into the sealed cavity; Step S 12 1. When the gas flow at the pressure relief port inlet monitored by the pressure detector is much greater than the gas flow through the sampling port, the pressure relief port and the moisture infrared detector are opened to discharge the mixed gas of the inert gas and the air containing impurity particles in the sealed cavity; Step S 13 , detect the reference voltage value of the mixed gas through infrared at the sampling port; Step S 14 , after the reference voltage value stabilizes, close the pressure relief port and sampling port.

4. A coal moisture infrared detection device, characterized in that: It includes a shell, a sample setting platform, a heating part, a pressure detector and a moisture infrared detector; The shell is surrounded to form a sealed cavity, and a sampling port and a pressure relief port communicating with the sealed cavity are provided on the top of the shell, and the sampling port and the pressure relief port are of on-off structure; The lofting platform is located at the bottom of the sealed cavity; The heating part is located on the lower surface of the sample setting platform and is used to dry the coal sample in the sample setting platform to separate water vapor; The moisture infrared detector is arranged on the sampling port and is used to detect the reference voltage value and also used to detect the response voltage value when the coal sample is dry; A pressure detector is provided at the inlet of the pressure relief port communicating with the sealed cavity, which is used to detect the gas flow at the inlet of the pressure relief port and also to detect the gas flow passing through the moisture infrared detector; The lower part of the shell is provided with an inert gas inlet connected with the sealed cavity, and the inert gas inlet is used to introduce inert gas into the sealed cavity to cooperate with the moisture infrared detector to detect the reference voltage value; First, an inert gas is introduced into the inert gas inlet, and a reference voltage value of the gas in the sealed cavity is determined by detecting the moisture infrared detector at the sampling port connected to the outside world. Then, the sampling port is kept isolated from the outside world, and a coal sample of known weight is heated in the sealed cavity to mix water vapor and the inert gas to reach an equilibrium state. The sampling port is opened, and the moisture infrared detector detects a response voltage value of the mixed gas. Finally, an absorbance response value is determined based on the response voltage value and the reference voltage value.

5. The coal moisture infrared detection device according to claim 4, characterized in that: It also includes a pressure control module, which is arranged on the pressure relief port and is used to detect whether the gas in the sealed cavity is saturated and to monitor whether the inert gas and water vapor in the sealed cavity have reached a balanced state.

6. The coal moisture infrared detection device according to claim 4, characterized in that: The layout platform also includes a connecting piece for radially limiting the sealing cavity; the connecting piece is abutted or fixedly connected to the shell.

7. The coal moisture infrared detection device according to claim 6, characterized in that: One end of the connecting member is fixedly connected to the inner surface of the top of the shell, and the other end is fixedly connected to the side wall of the lofting platform; and / or The connecting piece is a protrusion extending horizontally from the side wall of the lofting platform and is used for abutting against the inner wall of the shell.

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