Performance test method of coal on-line sample preparation device

Abstract

The invention discloses a performance test method of a coal online sample preparation device, which comprises the following steps: collecting all batches of test coal samples of the online sample preparation device to obtain a plurality of pairs of reserved samples and abandoned samples, and respectively measuring the total moisture value and as received basis lower calorific value of the reserved samples and the abandoned samples; calculating the sample preparation precision of the online sample preparation device according to the total moisture values of the reserved sample and the rejected sample and the low calorific value of the received basis; according to the sample preparation precision of the online sample preparation device, judging whether the sample preparation precision of the online sample preparation device meets the requirement or not; and according to the total moisture values of the reserved sample and the rejected sample and the received basis lower heating value, whether the sample preparation of the online sample preparation device is biased or not is judged. According to the method, the precision and bias calculation results are presented by the as-received basis lower calorific value, the results are more visual, and the method has higher reference significance; the method has the advantages of higher operability, shortened inspection period, no need of frequent starting and stopping of equipment, simple operation and shorter period, effectively avoids equipment loss caused by frequent starting and stopping of the equipment, and reduces the equipment failure rate.

Description

Technical Field

[0001] The invention belongs to the technical field of performance detection of an online sample preparation device of a thermal power plant, and relates to a performance detection method of an online coal sample preparation device. Background Art

[0002] In order to improve production efficiency and enhance the scientific and standardized management of fuel, thermal power companies have widely used coal mechanical sampling devices for the collection of coal entering the factory and the furnace. The mechanical sampling devices include samplers and online sampling devices. The sampling performance of the online sampling device is of vital importance for accurately obtaining representative coal quality results.

[0003] The existing national standards for performance tests of mechanical sampling and preparation equipment include precision verification, total moisture loss test and ash bias test. The precision test requires the collection of samples from at least 10 sampling units through the double or multiple methods for calculation. However, in actual production today, collecting samples from all 10 sampling units is time-consuming and affects power plant production. The total moisture loss and ash bias tests are carried out at the same time, but the coal conveyor belts need to be frequently started and stopped to take reference samples, which poses a great safety hazard to equipment operation and affects normal production work. In addition, the test results are expressed as the value of dry basis ash, which lacks a more intuitive reference significance for fuel management personnel who are accustomed to judging by calorific value indicators. Summary of the invention

[0004] In order to overcome the problems in the prior art that the performance test of the mechanical sampling device is time-consuming and affects the production of the power plant, the purpose of the present invention is to provide a performance inspection method for an online coal sampling device, which can accurately determine whether the performance of the online coal sampling device meets the requirements.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A performance testing method for an online coal sample preparation device comprises the following steps:

[0007] Collect test coal samples from the online sample preparation device until all batches of test coal samples are collected, and a total of L pairs of retained samples and discarded samples are obtained, L ≥ 10;

[0008] Determine the total moisture value and the received basic low calorific value of the retained sample and the discarded sample respectively;

[0009] According to the total moisture value and the received base low calorific value of the retained sample and the discarded sample, the sample preparation precision of the online sample preparation device is calculated;

[0010] According to the sample preparation precision of the online sample preparation device, calculate the upper limit of the sample preparation precision P u and the lower limit P L ,

[0011] If P u ≤P E , the sample preparation precision of the online sample preparation device meets the requirements; otherwise, the online sample preparation device does not meet the sample preparation precision requirements;

[0012] According to the total moisture value and the received basic low calorific value of the retained samples and discarded samples by L, the difference between the converted value of the received basic low calorific value of each retained sample and the reference value of the received basic low calorific value of each batch is obtained, and then the average value of the difference between the converted value of the received basic low calorific value of each retained sample and each reference value is calculated. According to the average value of the difference between the converted value of the received basic low calorific value of each retained sample and each reference value, the statistic t is calculated. z :

[0013] If t α >t z , then the sample preparation of the online sample preparation device is unbiased; if t α ≤t z , then there is sample preparation bias in the online sample preparation device, t α is the two-tailed t value with degrees of freedom.

[0014] Further, according to the total moisture value and the received base low calorific value of the retained sample and the discarded sample, the sample preparation precision of the online sample preparation device is calculated, including the following steps:

[0015] According to the total moisture values ​​of the retained samples and discarded samples by L, the weighted average of the total moisture of the test coal sample is calculated;

[0016] According to the weighted average of the received base low calorific value of the retained samples and the total moisture content of the test coal samples, the received base low calorific value conversion value of each retained sample is calculated; according to the weighted average of the received base low calorific value of the discarded samples and the total moisture content of the test coal samples, the received base low calorific value conversion value of each discarded sample is calculated;

[0017] Calculate the reference value of the received low calorific value of each batch according to the converted value of the received low calorific value of the retained sample and the converted value of the received low calorific value of the discarded sample;

[0018] According to the received base low calorific value conversion value of the retained sample and the received base low calorific value reference value, calculate the difference d of the reference value i ;

[0019] According to the difference d of the reference value i , calculate the standard deviation of the difference between the retained sample and the reference value of the online sample preparation device;

[0020] The sample preparation precision of the online sample preparation device is calculated based on the standard deviation of the difference between the retained sample and the reference value of the online sample preparation device.

[0021] Furthermore, the standard deviation s of the difference between the retained sample and the reference value of the online sample preparation device is calculated by the following formula:

[0022]

[0023] Furthermore, the sample preparation precision P of the online sample preparation device is twice the standard deviation of the difference between the retained sample and the reference value of the online sample preparation device.

[0024] Furthermore, the weighted average of the total moisture content of the test coal samples Calculated by the following formula:

[0025]

[0026] Among them, M t,iA M is the total moisture value of the sample, t,iD It is the total moisture value of the discarded sample.

[0027] Furthermore, each batch received a reference value of the base low calorific value Calculated by the following formula:

[0028]

[0029] in, The received low calorific value of the retained sample is converted into the value. It is the reference value of the received basic low heating value.

[0030] Furthermore, the difference d between the converted value of the basic low calorific value of each retained sample and the reference value of the basic low calorific value of each batch received i Calculated by the following formula:

[0031]

[0032] in, is the converted value of the received base low calorific value of each discarded sample, It is the reference value of the basic low calorific value received for each batch.

[0033] Furthermore, the upper limit of sample preparation precision P u =a u P; Lower limit of sample preparation precision P L =a L P;a u is the upper limit factor of precision, a L It is the lower limit factor of precision.

[0034] Furthermore, the received low calorific value of each retained sample is converted into Calculated by the following formula:

[0035]

[0036] The converted value of the received low calorific value of each discarded sample Calculated by the following formula:

[0037]

[0038] Among them, Q net,ar,iD For the discarded sample, the base low heat is received, M t,iA is the total moisture value of the retained sample, is the weighted average of the total moisture content of the test coal sample, Q net,ar,iA To keep the sample, the base temperature is low, M t,iD is the total moisture value of the discarded sample, It is the reference value of the basic low calorific value received for each batch.

[0039] Furthermore, the statistic t z Calculated by the following formula:

[0040]

[0041] in, is the average value of the difference between the converted value of the low calorific value of each retained sample and each reference value, and s is the standard deviation of the difference between the retained sample and the reference value of the online sample preparation device.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The performance test method of a coal online sample preparation device disclosed in the present invention has, first of all, a higher actual reference value. Compared with the ash content index used in the national standard test method, the precision and bias calculation results of the present invention are presented in terms of received base low calorific value, and the results are more intuitive and have a higher reference significance;

[0044] Secondly, it is more operable and shortens the inspection cycle. Compared with the national standard inspection method, which requires separate precision tests and bias tests, this method is carried out simultaneously with the actual production of the power plant, and does not require frequent start and stop of equipment. It is simple to operate and has a shorter cycle, which effectively avoids equipment loss caused by frequent start and stop of equipment and reduces equipment failure rate;

[0045] Thirdly, the calculation method is simple and feasible. The test process is highly operable, the calculation process is simple, the calculation results are highly reliable, and it is easy to implement.

[0046] The precision and bias of the coal online sample preparation device were tested by this method. The test process is simple and easy, with strong operability and reliable calculation results. The corresponding precision and bias value ranges can be calculated for different sources, coal types, varieties, batches and other conditions. The results are intuitively expressed in calorific value data, which has higher practical reference and application value. DETAILED DESCRIPTION

[0047] In order to facilitate understanding of the present invention, the present invention is described more fully below. The present invention can be implemented in a variety of different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0048] A performance testing method for an online coal sample preparation device of the present invention comprises the following steps:

[0049] 1) Determine the source, type, variety and batch quantity of test coal samples used for performance testing, and prepare the batch quantity of coal used for the test L (L≥10);

[0050] 2) Set the reduction ratio of the coal line sample preparation device to r, and set the expected precision (expressed as the received base low calorific value) to P E , the unit is J / g;

[0051] 3) According to the preset sampling plan, collect the first batch of test coal samples from the online sample preparation device, collect all retained samples (01A) and discarded samples (01D) respectively, and use the same sampling plan until the sampling and preparation of all batches of test coal samples are completed, and a total of L pairs of retained samples and discarded samples (01A~LA, 01D~LD) are obtained;

[0052] The pre-set sampling scheme is a sampling scheme determined for each coal plant based on actual conditions, which is a well-known technique in the art.

[0053] Each power plant has set up its own sampling plan for batch coal sampling according to the characteristics of coal. Since the coal used by each power plant is different, the sampling plans designed by different power plants will be different. This method is used to test whether the samples collected are representative for different sampling plans.

[0054] 3) Determine the total moisture value of the retained sample and the discarded sample according to the corresponding national standard method (the total moisture value of the retained sample M t,iA and the total moisture value of the discarded sample M t,iD , i = 01 ~ L) and received base low calorific value (retained sample received base low calorific value Q net,ar,iA And the discarded sample received the base low heat Q net,ar,iD , i=01~L);

[0055] 4) Calculate the weighted average of the total moisture content of the test coal sample based on the total moisture content of the retained and discarded samples.

[0056]

[0057] 5) Calculate the converted value of the received base low calorific value of each retained sample based on the received base low calorific value of the retained sample

[0058]

[0059] 6) Calculate the converted value of the received base low calorific value of each discarded sample based on the received base low calorific value of the discarded sample

[0060]

[0061] 7) Calculate the reference value of the received low calorific value of each batch based on the received low calorific value conversion value of the retained sample and the received low calorific value conversion value of the discarded sample

[0062]

[0063] 8) Calculate the value based on the received low calorific value of the retained sample and the reference value of the received basic low calorific value Calculate the difference d between the converted value of the received basic low calorific value of each retained sample and the reference value of the received basic low calorific value of each batch i :

[0064]

[0065] 9) According to the difference d between the converted value of the basic low calorific value of each retained sample and the reference value of the basic low calorific value of each batch i , calculate the standard deviation s of the difference between the retained sample and the reference value of the online sample preparation device:

[0066]

[0067] 10) According to the standard deviation s of the difference between the retained sample and the reference value of the online sample preparation device, calculate the sample preparation precision P of the online sample preparation device: P = 2s;

[0068] 11) Check the precision range calculation factor table corresponding to the precision upper limit factor a u and the lower limit factor a L , according to the sample preparation precision of the online sample preparation device, calculate the upper limit of the sample preparation precision P u and the lower limit P L , then the sample preparation precision of the online sample preparation device falls within P with a confidence probability of 95%. L and P u The upper limit of sample preparation precision is P u =a u P; Lower limit of sample preparation precision P L =a L P;

[0069] If P u ≤P E, the sample preparation precision of the online sample preparation device meets the requirements; otherwise, if the online sample preparation device does not meet the sample preparation precision requirements, the reason should be found out and the reduction ratio, i.e., the reduction ratio, should be adjusted until the sample preparation precision does not exceed the expected precision P E value.

[0070] 12) According to the difference d between the converted value of the basic low calorific value of each retained sample and the reference value of the basic low calorific value of each batch i Calculate the average value of the difference between the converted value of the base low calorific value of each retained sample and each reference value

[0071]

[0072] 13) According to the average value of the difference between the converted value of the base low calorific value of each retained sample and each reference value Calculate the statistic t z :

[0073]

[0074] Degree of freedom f = L-1, and the two-tailed t value of the degree of freedom f can be obtained from Table 12 of GB / T19494.3-2004 α .

[0075] If t α >t z , then the sample preparation of the online sample preparation device is unbiased;

[0076] If t α ≤t z , then there is a sample preparation bias in the online sample preparation device, and the bias value B is calculated as follows (95% confidence level):

[0077]

[0078] Example 1

[0079] The performance test method of the online sampling device of the mechanical sampling equipment for incoming coal in a thermal power plant A is as follows:

[0080] 1) Determine that the test coal sample used for performance inspection is the bituminous coal raw coal transported by train from a certain H mine, with a batch quantity of 3000t, and prepare the batch quantity of coal used for the test L=10;

[0081] 2) Set the reduction ratio of the online sample preparation device to r = 20 (i.e., the reduction ratio is 1:20) and determine the expected precision P E =200 J / g;

[0082] 3) According to the pre-set sampling plan, the first batch of test coal samples are taken, and all retained samples (01A) and discarded samples (01D) are collected respectively. The same sampling plan is adopted until the sampling and preparation of all batches of test coal samples are completed, and a total of 10 pairs of retained samples and discarded samples (01A-10A, 01D-10D) are obtained;

[0083] 3) Determine the total moisture value (M) of 10 pairs of samples according to the corresponding national standard method. t,iA and M t,iD , i = 01 ~ 10) and the received base low calorific value (Q net,ar,iA and Q net,ar,iD , i=01~10); the specific values ​​are as follows:

[0084]

[0085]

[0086] 4) Calculate the weighted average of the total moisture content of the test coal sample

[0087]

[0088] 5) Calculate the received base low calorific value conversion value of each retained sample:

[0089]

[0090] The specific values ​​are as follows:

[0091]

[0092]

[0093] 6) Calculate the received base low calorific value of each discarded sample:

[0094]

[0095] The specific values ​​are as follows:

[0096]

[0097]

[0098] 7) Calculate the reference value of the received basic low calorific value of each batch:

[0099]

[0100] The specific values ​​are as follows:

[0101]

[0102] 8) Calculate the difference between the converted value of the base low calorific value of each retained sample and the reference value of each batch:

[0103]

[0104] The specific values ​​are as follows:

[0105]

[0106]

[0107] 9) Calculate the standard deviation s of the difference between the retained sample and the reference value of the online sample preparation device:

[0108]

[0109] 10) Calculate the sample preparation precision P of the online sample preparation device: P = 2s = 2 × 52.11 = 104.22

[0110] 11) Check the precision range calculation factor table corresponding to the precision upper limit factor a u =1.75 and lower limit factor a L =0.70, calculate the upper limit of sample preparation precision P u and the lower limit P L :

[0111] Upper limit P u =a u P = 1.75 × 104.22 = 182

[0112] Lower limit P L =a L P = 0.70 × 104.22 = 73

[0113] Then the sample preparation precision of the online sample preparation device falls within the range of 73 J / g and 182 J / g at a confidence probability of 95%;

[0114] P u =182J / g <P E =200J / g, the sample preparation precision of the online sample preparation device meets the requirements.

[0115] 12) Calculate the average value of the difference between the converted value of the base low calorific value of each retained sample and each reference value

[0116]

[0117] 13) Calculate the statistic t z :

[0118]

[0119] The degree of freedom f = 10-1 = 9. The two-tailed t value of the degree of freedom f is obtained from Table 12 of GB / T19494.3-2004. α =2.262.

[0120] t α <t z , then there is a sample preparation bias in the online sample preparation device, and the bias value B is calculated as follows (95% confidence level):

[0121]

[0122] That is, the online sample preparation device is used for 3000t of raw and batch bituminous coal transported by train from a certain H mine. According to the routine sampling plan, the sample preparation precision meets the expected value of 200J / g. There is a sample preparation bias, and the bias value falls within the range of 279J / g to 353J / g (i.e. 66.7kcal / kg to 84.4kcal / kg) with a 95% confidence probability.

[0123] The above description is only for the best embodiment of the present invention, but it should not be understood as limiting the claims. The present invention is not limited to the above embodiments, and its specific structure is allowed to be changed. However, all changes made within the protection scope of the independent claims of the present invention are within the protection scope of the present invention.

[0124] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

Claims

1. A performance testing method for an online coal sample preparation device, characterized in that: The following steps are involved: Collect test coal samples from the online sample preparation device until all batches of test coal samples are collected, and a total of L pairs of retained samples and discarded samples are obtained, L ≥ 10; Determine the total moisture value and the received basic low calorific value of the retained sample and the discarded sample respectively; According to the total moisture value and the received base low calorific value of the retained sample and the discarded sample, the sample preparation precision of the online sample preparation device is calculated; According to the sample preparation precision of the online sample preparation device, calculate the upper limit of the sample preparation precision P u and the lower limit P L , If P u ≤P E , the sample preparation precision of the online sample preparation device meets the requirements; otherwise, the online sample preparation device does not meet the sample preparation precision requirements; According to the total moisture value and the received basic low calorific value of the retained samples and discarded samples by L, the difference between the converted value of the received basic low calorific value of each retained sample and the reference value of the received basic low calorific value of each batch is obtained, and then the average value of the difference between the converted value of the received basic low calorific value of each retained sample and each reference value is calculated. According to the average value of the difference between the converted value of the received basic low calorific value of each retained sample and each reference value, the statistic t is calculated. z : If α >t z , then the sample preparation of the online sample preparation device is unbiased; if t α ≤t z , then there is sample preparation bias in the online sample preparation device, t α is the two-tailed t value with degrees of freedom.

2. The performance testing method of a coal online sample preparation device according to claim 1, characterized in that: According to the total moisture value of the retained sample and the discarded sample and the received base low calorific value, the sample preparation precision of the online sample preparation device is calculated, including the following steps: According to the total moisture values ​​of the retained samples and discarded samples by L, the weighted average of the total moisture of the test coal sample is calculated; According to the weighted average of the received base low calorific value of the retained samples and the total moisture content of the test coal samples, the received base low calorific value conversion value of each retained sample is calculated; according to the weighted average of the received base low calorific value of the discarded samples and the total moisture content of the test coal samples, the received base low calorific value conversion value of each discarded sample is calculated; Calculate the reference value of the received low calorific value of each batch according to the converted value of the received low calorific value of the retained sample and the converted value of the received low calorific value of the discarded sample; According to the received base low calorific value conversion value of the retained sample and the received base low calorific value reference value, calculate the difference d of the reference value i ; According to the difference d of the reference value i , calculate the standard deviation of the difference between the retained sample and the reference value of the online sample preparation device; The sample preparation precision of the online sample preparation device is calculated based on the standard deviation of the difference between the retained sample and the reference value of the online sample preparation device.

3. The performance testing method of a coal online sample preparation device according to claim 2, characterized in that: The standard deviation s of the difference between the retained sample and the reference value of the online sample preparation device is calculated by the following formula:

4. The performance testing method of a coal online sample preparation device according to claim 2, characterized in that: The sample preparation precision P of the online sample preparation device is twice the standard deviation of the difference between the retained sample and the reference value of the online sample preparation device.

5. The performance testing method of a coal online sample preparation device according to claim 2, characterized in that: Weighted average of total moisture content of test coal samples Calculated by the following formula: Among them, M t,iA M is the total moisture value of the sample, t,iD It is the total moisture value of the discarded sample.

6. The performance testing method of a coal online sample preparation device according to claim 1, characterized in that: The reference value of the base low calorific value received by each batch Calculated by the following formula: in, The received low calorific value of the retained sample is converted into the value. It is the reference value of the received basic low heating value.

7. The performance testing method of a coal online sample preparation device according to claim 1, characterized in that: The difference between the converted value of the received basic low calorific value of each retained sample and the reference value of the received basic low calorific value of each batch d i Calculated by the following formula: in, is the converted value of the received base low calorific value of each discarded sample, It is the reference value of the basic low calorific value received for each batch.

8. The performance testing method of a coal online sample preparation device according to claim 1, characterized in that: The upper limit of sample preparation precision P u =a u P; Lower limit of sample preparation precision P L =a L P;a u is the upper limit factor of precision, a L It is the lower limit factor of precision.

9. The performance testing method of a coal online sample preparation device according to claim 1, characterized in that: The converted value of the received low calorific value of each retained sample Calculated by the following formula: The converted value of the received low calorific value of each discarded sample Calculated by the following formula: Among them, Q net,ar,iD For the discarded sample, the base low heat is received, M t,iA is the total moisture value of the retained sample, is the weighted average of the total moisture content of the test coal sample, Q net,ar,iA To keep the sample, the base temperature is low, M t,iD is the total moisture value of the discarded sample, It is the reference value of the basic low calorific value received for each batch.

10. The performance testing method of a coal online sample preparation device according to claim 1, characterized in that: Statistic t z Calculated by the following formula: in, is the average value of the difference between the converted value of the low calorific value of each retained sample and each reference value, and s is the standard deviation of the difference between the retained sample and the reference value of the online sample preparation device.

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