A sampling method for accurately collecting coal samples according to furnace numbers

Abstract

The present invention discloses a sampling method for accurately collecting coal samples by furnace number, and the steps are as follows: determining the furnace position number according to the warehouse entry status, adjusting the sampling cycle, and determining the sub-sample quantity; scanning the position number of the target sample collecting tank, and counting and determining it through the switching action of the corresponding proximity limit switch; the present invention can better meet the requirements of refined coal management sampling, that is, furnace sampling assessment through the overall method flow, and does not require large direct investment costs, and does not require the original sampler to be modified, thus saving time and energy, making the normal warehouse entry of coal in the power plant and the operation of the unit smoother, and on the basis of the original single set of coal sampling device entering the plant, a practical and feasible technical transformation scheme is formulated, and the single set of coal sampling device entering the plant is realized. Double-sided coal transportation and accurate coal sampling by furnace number are achieved, which not only saves equipment investment, but also avoids the operation risk brought by construction to the coal warehouse entry of the power plant.

Description

Technical Field

[0001] The invention relates to the technical field of coal sample collection, and in particular to a sampling method for accurately collecting coal samples according to furnace numbers. Background Art

[0002] Coal sampling refers to an important part of the quality control of the raw coal receiving process of the coking plant. The quality of the coal transported to the coking plant is not uniform, so samples should be taken from different parts of the incoming coal. The original sub-samples taken are mixed, crushed and reduced for analysis and inspection. The more sampling points there are, the more representative the sample is, that is, the closer the quality of the sample is to the quality of the batch of raw coal. When sampling on the belt conveyor, the whole section of the coal flow should be intercepted. The sampling location can be in the middle or head unloading of the belt conveyor. When sampling in the middle, the sampler must be close to the belt surface, and it is not allowed to shovel the coal flow in the air. With the increase of the belt speed and bandwidth of the belt conveyor. Manual sampling methods are no longer suitable, so an automatic timing mechanical sampler must be set up. The minimum number of sub-samples for each batch of coal is the same as when taking slices from the coal pile in the coal storage yard.

[0003] The existing method of collecting coal samples is to install sampling machines on different belts and use the corresponding unit's coal sampling machine configuration method. This not only has a large direct investment cost, but also still needs to modify the original sampling machine, which is labor-intensive and time-consuming. It will affect the normal storage of coal in the power plant and the operation of the unit for a long time, and the indirect cost is relatively large. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a sampling method for accurately collecting coal samples according to furnace numbers.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A sampling method for accurately collecting coal samples according to furnace numbers, the steps of which are as follows:

[0007] The head and tail center distance and belt speed of the warehouse feeding belt conveyor are set through the controller;

[0008] Turn on the power, set the time for the coal to travel from the sampling point to the furnace through the controller, and start feeding the coal;

[0009] Determine the furnace position number according to the warehouse entry status, adjust the sampling cycle, adjust the rotation speed of the sample tank, sample with the sampling head, and determine the sub-sample quantity;

[0010] Frequently switch between the coal bunkers for different furnaces, set the coal feeding time, and complete fine coal blending;

[0011] Scan the position number of the target sample collection tank, and count and determine it through the switching action of the corresponding proximity limit switch;

[0012] Check the coal sample of a single tank to determine whether it meets the maximum coal sampling quantity of a single furnace per day; when the fixed sampling quantity is exceeded during operation, stop releasing sub-samples to the sample tank;

[0013] Start the baffle to block the coal, switch the tank position of the sampler, and carry out the next sampling;

[0014] After sampling is completed, the coal sampling machine is turned off through the programmable control cabinet to stop sampling.

[0015] Preferably, the programmable control cabinet PLC in the controller of step 1 adds 8 output points DO and 8 groups of relay contacts, and adds a DO module. The protocols of the coal control PLC and the coal sampling PLC entering the furnace are different, and communication cannot be established directly. A multi-core communication cable with a shielded layer is used to provide a communication channel between the PLCs. A control communication cable is laid from the coal control PLC cabinet to the coal sampling control box entering the furnace to transmit the operating furnace position signal. The coal sampling PLC entering the furnace adds 8 input empty points DI to obtain the storage position signals of the four furnaces, and the coal sampling control box entering the furnace PLC adds a DI module.

[0016] Preferably, the storage conveyor supplied in step 1 is a closed belt, and the material inlet is equipped with a gate for adjusting the thickness of the coal seam to ensure uniform flow and prevent blockage. All storage conveyors can be steplessly adjusted to ensure uniform feeding and smooth starting and stopping.

[0017] Preferably, the sampling speed of the coal scraper plate of the sampling head in step 3 matches the speed of the coal conveyor belt of the storage belt conveyor, and can sample coal samples from the entire cross-section of the coal flow. The sampling period of the sampling head is adjustable or can be adjusted according to the number of sub-samples collected so that all the collected coal samples fall into the sample tank.

[0018] Preferably, in step 3, a rotary sample collector is used, which should be sealed and dustproof and capable of automatically collecting samples and packaging, automatically replacing sample collecting cans, and having a can position marking device; when the last sample collecting can is full, a signal is sent to remind the operator to prepare to change cans; a signal is sent after sample preparation is completed, and a reminder display is set on site.

[0019] Preferably, the sub-sample size in step 3 is determined by the width of the coal feeding belt, the amount of coal fed and the maximum particle size of the coal flow, so as to actually sample the entire cross-section of the coal flow without leaving any bottom coal.

[0020] Preferably, the sampling period of step 3 should be based on The sampling period is evenly distributed according to the calculated number of sub-samples; when intermittent coal feeding is carried out, it should be adjusted according to the coal feeding flow rate. When the flow rate is large, the sampling period should be shortened, and the sampling period should be extended accordingly. Avoid the head and tail parts of the coal flow when sampling.

[0021] Preferably, in step 5, when scanning the target collection tube, the following formula is used: Determine the position number of the target sample collection tank, where D(i,j) is the Euclidean distance between two characters, F`(m,n) is the sample to be identified, and F(m,n) is the template in the knowledge base. At the beginning of identification, it is required to calculate the distance between the image to be identified and each template in the standard template library. The numbers in the standard template library are compared one by one. The smaller D(i,j) is, the better the match between the sample to be identified and the standard template is. If it is zero, it means that the two are completely matched.

[0022] It can also be calculated according to the following formula: Where A(k) is the weight of the kth feature, F`(k) and F(k) are the kth features of a template in the template library and the character to be matched, respectively, and D(i) is the matching value, which indicates the degree of difference between the features of the matching character and the features of the template character. The smaller the matching value, the more consistent the features of the two characters.

[0023] Preferably, when checking a single tank coal sample, step 6 should be able to meet the maximum coal sampling requirement of a single furnace in a single day, and have sufficient margin, generally exceeding 30%. When the set sampling quantity is exceeded during operation, the release of sub-samples to the sample collecting tank is stopped.

[0024] Preferably, in the specific steps of step 7, when the baffle is started to block the coal, since the target sample collecting tank is in a dynamic state, it is necessary to switch the tank position of the sampler accordingly, and prevent the sub-sample from falling into the tank during the switching process.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention, through the overall method flow, can better meet the requirements of refined coal management sampling, that is, furnace sampling assessment, and does not require large direct investment costs, nor does it require modification of the original sampler, saving time and energy, making the normal storage of coal in the power plant and the operation of the unit smoother. On the basis of the original single set of coal sampling device entering the plant, a practical and feasible technical transformation plan has been formulated, which realizes the double-sided coal transportation of the single set of coal sampling device entering the plant and the accurate collection of coal samples by furnace number, which not only saves equipment investment, but also avoids the operational risks brought by construction to the storage of coal in the power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic flow chart of a sampling method for accurately collecting coal samples by furnace number proposed by the present invention;

[0027] Figure 2 A schematic diagram of the control connection of sampling of coal entering a furnace by furnace in a sampling method for accurately collecting coal samples by furnace number proposed by the present invention;

[0028] Figure 3 The invention discloses a network structure for sampling coal by furnace according to furnace number in a sampling method for accurately collecting coal samples by furnace number. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0030] Reference Figure 1-3 A method for accurately collecting coal samples by furnace number is provided, and the steps are as follows:

[0031] The head and tail center distance and belt speed of the warehouse conveyor are set through the controller. The programmable control cabinet PLC in the controller adds 8 output points DO and 8 groups of relay contacts, and adds a DO module. The coal control PLC and the furnace coal sampling PLC have different protocols and cannot directly establish communication. A multi-core communication cable with a shielded layer is used to provide a communication channel between the PLCs. A control communication cable is laid from the coal control PLC cabinet to the furnace coal sampling control box to transmit the running furnace position signal. The furnace coal sampling PLC adds 8 input empty points DI to obtain the warehouse position signals of the four furnaces. The furnace coal sampling control box PLC adds a DI module. The warehouse conveyor supplied is a closed belt. The material inlet is equipped with a gate to adjust the thickness of the coal seam to ensure uniform flow and prevent blockage. All warehouse conveyors can adjust the speed steplessly to ensure uniform feeding and smooth start and stop.

[0032] Turn on the power, set the time for the coal to travel from the sampling point to the furnace through the controller, and start feeding the coal;

[0033] Determine the furnace number according to the warehouse entry status and adjust the sampling cycle. The sampling cycle should be based on The number of sub-samples is calculated to evenly distribute the sampling period;

[0034] In the formula, n is the number of sub-samples to be collected;

[0035] i is the assumption that the power plant operates in i shifts per day, and the amount of coal supplied to each shift is evenly distributed;

[0036] P is the sampling precision. If ±1% is taken, substitute P=1 into the above formula;

[0037] σ is based on the average ash content of the coal (or coal entering the furnace) on a dry basis (A d ) is used as the basis to calculate the standard deviation of the m average ash contents; the calculation formula is as follows: Where;

[0038] m is the number of days for statistical ash content, and m should be greater than 300;

[0039] A d The average ash content of coal entering the plant (or coal entering the furnace) on a dry basis;

[0040] For m A d The average value of

[0041] If the amount of coal is not evenly distributed each time, but in different proportions, j Coal loading, then the number of sub-samples to be taken for the jth time is n j , calculated as follows; In the formula,

[0042] n j is the number of sub-samples to be collected for the jth time;

[0043] r j is the jth coal loading ratio, i.e. r j is the proportion of the jth coal loading to the total coal loading, and ∑r j =1, that is, r1+r2+…+r j +…r i =1; adjust the rotation speed of the sample tank, the sampling head takes samples, and determines the sub-sample quantity. The sub-sample quantity is determined by the width of the coal feeding belt, the amount of coal fed and the maximum particle size of the coal flow. It is appropriate to actually take the entire cross-section of the coal flow without leaving the bottom coal. The sampling speed of the sampling head matches the speed of the coal conveyor belt of the storage belt conveyor, and can take out coal samples from the entire cross-section of the coal flow. The sampling cycle of the sampling head is adjustable or can be adjusted according to the number of collected sub-samples so that all the collected coal samples fall into the sample tank. A rotary sample collector is used, which should be sealed and dustproof and can automatically collect samples and package, automatically replace the sample tank, and set a tank position marking device; when the last sample tank is full, a signal is issued to remind the operator to prepare to change the tank; a signal is issued after the sample preparation is completed, and a reminder display is set on site; when intermittent coal feeding is carried out, it should be adjusted according to the coal feeding flow rate. When the flow rate is large, the sampling cycle should be shortened, and the sampling cycle should be extended accordingly, and the head and tail parts of the coal flow should be avoided when sampling.

[0044] Frequently switch between the coal bunkers for different furnaces, set the coal feeding time, and complete fine coal blending;

[0045] The position number of the target sample collection tank is scanned, and the counting is determined by the switch action of the corresponding proximity limit switch. When scanning the target collection tube, according to the following formula: Determine the position number of the target sample collection tank, where D(i,j) is the Euclidean distance between two characters, F`(m,n) is the sample to be identified, and F(m,n) is the template in the knowledge base. At the beginning of identification, it is required to calculate the distance between the image to be identified and each template in the standard template library. The numbers in the standard template library are compared one by one. The smaller D(i,j) is, the better the match between the sample to be identified and the standard template is. If it is zero, it means that the two are completely matched.

[0046] It can also be calculated according to the following formula: In the formula, A(k) is the weight of the kth feature, F`(k) and F(k) are the kth features of a template in the template library and the character to be matched, respectively, and D(i) is the matching value, which indicates the degree of difference between the features of the matching character and the features of the template character. The smaller the matching value, the more consistent the features of the two characters. The weighting coefficient needs to be determined through continuous experiments to achieve better classification results.

[0047] The algorithm is described as follows:

[0048] Let i = 0, j = 0;

[0049] ① Take the i-th character and compare it with the j-th template in the template library;

[0050] ② Compare the 1st, 4th, and 6th features, and the value of A(k) is 2; compare the 2nd, 5th, and 9th features, and the value of A(k) is 0.5; compare the 3rd, 7th, and 8th features, and the value of A(k) is 1. "j++", if all templates are matched, go to step ③ to execute, otherwise go back to step ① to execute.

[0051] ③ Take out the smallest template matching value and use the template character as the character that successfully matches the current character. "i++, j=0", return to step ① to execute;

[0052] The coal sample of a single tank should be able to meet the maximum coal sampling requirement of a single furnace in a single day, and have sufficient margin, generally more than 30%. When the fixed sampling quantity is exceeded during operation, the release of sub-samples to the sample tank should be stopped;

[0053] When the baffle is started to block the coal, since the target sample collection tank is in a dynamic state, the sampler switching tank position needs to be switched accordingly, and the sub-samples need to be prevented from falling into the tank during the switching process;

[0054] After sampling is completed, the coal sampling machine is turned off through the programmable control cabinet to stop sampling.

[0055] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0056] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0057] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A sampling method for accurately collecting coal samples according to furnace numbers, characterized in that: The steps are as follows: Step 1: Set the head and tail center distance and belt speed of the warehouse feeding belt conveyor through the controller; Step 2: Turn on the power, set the time for the coal to travel from the sampling point to the furnace through the controller, and start feeding the coal; Step 3: Determine the furnace position number according to the warehouse entry status, adjust the sampling cycle, adjust the rotation speed of the sample collection tank, sample with the sampling head, and determine the sub-sample volume; Step 4: Frequently switch between the coal bunkers for different furnaces, set the coal feeding time, and complete fine coal blending; Step 5: Scan the position number of the target sample collection tank, and count and determine it through the switch action of the corresponding proximity limit switch; check the coal sample of a single tank to determine whether it meets the maximum sampling coal quantity of a single furnace in a single day; Step 6: When the set sampling quantity is exceeded during operation, stop releasing the sub-samples to the sample collection tank; Step 7: Start the baffle to block the coal, switch the tank position of the sampler, and carry out the next sampling; After sampling is completed, the coal sampling machine for entering the furnace is closed through the program-controlled cabinet to stop sampling; the program-controlled cabinet PLC in the controller of step 1 adds 8 output points DO and 8 groups of relay contacts, and adds a DO module. The coal control PLC and the coal sampling PLC for entering the furnace have different protocols and cannot directly establish communication. A multi-core communication cable with a shielded layer is used to provide a communication channel between the PLCs. A control communication cable is laid from the coal control PLC cabinet to the coal sampling control box for entering the furnace to transmit the furnace position signal of the operation. The coal sampling PLC for entering the furnace adds 8 input empty points DI to obtain the warehouse position signals of the four furnaces, and the coal sampling control box PLC for entering the furnace adds a DI module; the sampling period of step 3 should be based on n= The sampling period is evenly distributed by calculating the number of sub-samples, where n is the number of sub-samples to be collected, i is the assumption that the power plant is in i-shift system and the amount of coal in each shift is evenly distributed, P is the sampling precision, σ is based on the average ash content Ad of the coal entering the plant or the furnace on a dry basis, and the standard deviation of a total of m average ash contents is calculated, and m is the number of days for the statistical ash content. The average ash content of the coal entering the factory or the furnace on a dry basis. When intermittent coal feeding is carried out, it should be adjusted according to the coal feeding flow rate. When the flow rate is large, the sampling period should be shortened, and the sampling period should be extended. When sampling, avoid the head and tail of the coal flow. When scanning the target sample tube in step 5, according to the following formula: D (i, j) = , determine the position number of the target sample collection tank, where D(i,j) is the Euclidean distance between two characters, F`(m,n) is the sample to be identified, and F(m,n) is the template in the knowledge base. At the beginning of recognition, it is required to calculate the distance between the image to be identified and each template in the standard template library. The numbers in the standard template library are compared one by one. The smaller D(i,j) is, the better the match between the sample to be identified and the standard template is. If it is zero, it means that the two are completely matched. It can also be based on the following formula, D(i)= , where A(k) is the weight of the kth feature, F`(k) and F(k) are the kth features of a template in the template library and the character to be matched, respectively, and D(i) is the matching value, which indicates the degree of difference between the features of the matching character and the features of the template character. The smaller the matching value, the more consistent the features of the two characters.

2. A method for accurately collecting coal samples by furnace number according to claim 1, characterized in that: The storage belt conveyor provided in step 1 is a closed belt, and the material inlet is equipped with a gate for adjusting the thickness of the coal seam to ensure uniform flow and prevent blockage. All storage belt conveyors can be steplessly adjusted to ensure uniform feeding and smooth starting and stopping.

3. The method for accurately collecting coal samples by furnace number according to claim 1 is characterized in that: The sampling speed of the coal scraper plate of the sampling head in step 3 matches the speed of the coal conveyor belt of the storage belt conveyor, and can sample coal samples from the entire cross-section of the coal flow. The sampling period of the sampling head is adjustable or can be adjusted according to the number of collected sub-samples so that all the collected coal samples fall into the sample collecting tank.

4. The method for accurately collecting coal samples by furnace number according to claim 1 is characterized in that: In step 3, a rotary sample collector is used, which should be sealed and dustproof and be able to automatically collect samples and package, automatically replace sample collecting cans, and be equipped with a can position marking device; when the last sample collecting can is full, a signal is sent to remind the operator to prepare to change the can; a signal is sent after the sample preparation is completed, and a reminder display is set on site.

5. The method for accurately collecting coal samples by furnace number according to claim 1 is characterized in that: The amount of sub-samples in step 3 is determined by the width of the coal feeding belt, the amount of coal fed and the maximum particle size of the coal flow, and it is appropriate to actually sample the entire cross-section of the coal flow without leaving any bottom coal.

6. The method for accurately collecting coal samples by furnace number according to claim 1 is characterized in that: When checking a single tank coal sample, step 6 should be able to meet the maximum coal sampling requirement of a single furnace in a single day, and have sufficient margin, generally exceeding 30%. When the fixed sampling quantity is exceeded during operation, the release of sub-samples to the sample collecting tank is stopped.

7. The method for accurately collecting coal samples by furnace number according to claim 1 is characterized in that: The specific steps of step 7 are as follows: when the baffle is started to block the coal, since the target sample collection tank is in a dynamic state, it is necessary to switch the tank position of the sampler accordingly, and prevent the sub-sample from falling into the tank during the switching process.

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