A method for calculating the correction of total moisture loss in the coal sampling, preparation and analysis process of thermal power plants

Abstract

A method for calculating the correction of the total moisture loss in the coal sampling, preparation and analysis process of a thermal power plant includes the following steps: conducting a total moisture loss test on the test coal sample to obtain the total moisture loss value; preparing a total moisture test sample from the test coal sample using a combined crushing and splitting sample preparation device, and calculating the total moisture loss rate of the total moisture test sample; weighing the total moisture test sample and recording the total moisture loss rate; measuring the total moisture value of the total moisture test sample; calculating the correction of the total moisture loss in the coal sampling, preparation and analysis process of the thermal power plant based on the total moisture loss value, the total moisture loss rate of the total moisture test sample, the recorded total moisture loss rate, and the total moisture value of the total moisture test sample.

Description

Technical Field

[0001] The invention belongs to the technical field of the calculation of the coal received by thermal power plants, and relates to a method for calculating the correction of the total moisture loss in the coal sampling, sample preparation and analysis process of thermal power plants. Background Art

[0002] At present, most of the settlements of the coal received by thermal power plants are based on the low calorific value and quality of the coal. The total moisture value is one of the most important parameters affecting the calculation result of the low calorific value of the coal. The low calorific value decreases with the increase of the total moisture, and they are inversely proportional. Statistics show that when the total moisture of coal increases by 1%, the received-base low calorific value decreases by about (60 - 70) cal / g, and the higher the calorific value, the greater the impact. With the continuous increase of the standard coal unit price, taking the daily incoming 10000 tons of steam coal with a calorific value of 5000 kcal and a delivered unit price of 1000 yuan / ton as an example, for every 1% reduction in the total moisture, the daily procurement cost of the power plant increases by about 120,000 yuan. Therefore, in recent years, how to correct the total moisture value has become one of the most important considerations for thermal power plants to reduce production costs. At present, most power plants use the total moisture value tested in the laboratory as the total moisture value for calculating the low calorific value, without considering the total moisture loss during sampling, sample preparation, transportation and storage. A few power plants consider the total moisture correction, but there is no basis for choosing the correction value. Most thermal power plants implement separate management of the coal received and the coal fed into the furnace. The accuracy of the calorific value of the coal fed into the furnace affects boiler operation indicators, balance calculation, calorific value difference calculation, etc. Therefore, the total moisture correction calculation in the coal sampling, sample preparation and analysis process of the coal fed into the furnace plays an important role and practical significance in the fuel management of thermal power plants. Summary of the Invention

[0003] To overcome the problems in the prior art, the purpose of the invention is to provide a method for calculating the correction of the total moisture loss in the coal sampling, sample preparation and analysis process of thermal power plants.

[0004] To achieve the above purpose, the technical solution adopted by the invention is as follows:

[0005] A method for calculating the correction of the total moisture loss in the coal sampling, sample preparation and analysis process of thermal power plants includes the following steps:

[0006] Conduct a total moisture loss test on the test coal sample to obtain the total moisture loss value;

[0007] Use a combined crushing and reduction sample preparation device to prepare a total moisture test sample from the test coal sample, and calculate the total moisture loss rate of the total moisture test sample;

[0008] Weigh the total moisture test sample and record the total moisture loss rate during transportation and storage;

[0009] Measure the total moisture value of the total moisture test sample;

[0010] Calculate the correction of total moisture loss in the coal sampling, preparation, and analysis process of thermal power plants based on the total moisture loss value, the total moisture loss rate of the total moisture sample, the recorded total moisture loss rate, and the total moisture value of the total moisture sample.

[0011] A further improvement of the present invention is that the test coal sample is obtained by a mechanical sampling and sample preparation device.

[0012] A further improvement of the present invention is that the total moisture loss test is carried out according to the method of GB / T 19494.3.

[0013] A further improvement of the present invention is that when carrying out the total moisture loss test, the number of test pairs is n p = 20, the standard deviation of differences is s d = 0.40, and the average value of differences is

[0014] A further improvement of the present invention is that the total moisture loss rate is calculated according to the method of DL / T 1339.

[0015] A further improvement of the present invention is that the recorded total moisture loss rate does not exceed 1.0%.

[0016] A further improvement of the present invention is that the total moisture value of the total moisture sample is determined according to GB / T 211.

[0017] A further improvement of the present invention is that the test coal sample is corrected according to the correction of total moisture loss in the coal sampling, preparation, and analysis process of thermal power plants. The total moisture value M of the corrected test coal sample t,A is:

[0018]

[0019] Where: M1 - the total moisture loss rate during the transportation and storage of the prepared sample to the laboratory;

[0020] L M - the total moisture loss rate of the sample prepared by the combined crushing and splitting sample preparation equipment;

[0021] M t0 - the total moisture value of the total moisture sample determined according to GB / T 211;

[0022] - the average value of differences in the total moisture loss test;

[0023] s d - the standard deviation of differences in the total moisture loss test;

[0024] n p - the number of test pairs in the total moisture loss test;

[0025] t β ​​​​—— The one-tailed t value corresponding to the degree of freedom (n p - 1) obtained from the t value table at a 95% confidence probability.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] The present invention comprehensively considers factors in the calculation method for correcting the total moisture loss. For the preparation of total moisture test samples through a combined crushing and splitting sample preparation device, the total moisture loss factors of the sampling device, transportation, and storage processes are all taken into account; the parameters used in the calculation method are easily obtainable. When there are many coal samples that need to be corrected for total moisture, the required parameters can be obtained through the relevant test methods described in this method; the results of correcting the total moisture loss in the coal sampling, preparation, and analysis process by this method are accurate, reliable, convenient, and fast, and have high practical guiding significance.

[0028] Furthermore, the test coal samples are obtained through a mechanical sampling and sample preparation device, and the performance of the sample preparation device is considered in the calculation of total moisture correction, which is beneficial to the accuracy of the calculation results.

[0029] Furthermore, the calculation result of total moisture correction is the range of the total moisture value of the raw coal sample at a 95% confidence probability, and the calculation result has strong practical applicability and reliability. Detailed implementation manners

[0030] To facilitate the understanding of the present invention, the present invention will be described more comprehensively through embodiments below. Preferred embodiments of the present invention are given in the embodiments. However, the present invention can be implemented in many 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 thorough and comprehensive.

[0031] The mechanical sampling and sample preparation device and the combined crushing and splitting sample preparation device in the present invention are devices in the prior art.

[0032] A method for calculating the correction of total moisture loss in the coal sampling, preparation, and analysis process of thermal power plants includes the following steps:

[0033] The first step: Select test coal sample A, take the test coal sample with a mechanical sampling and sample preparation device, conduct a total moisture loss test according to GB / T19494.3, and the number of test pairs is n p , the standard deviation of the difference is s d , and the average value of the difference is to obtain the total moisture loss value;

[0034] The second step: Use the combined crushing and splitting sample preparation device to prepare total moisture test samples from the test coal samples taken by the mechanical sampling and sample preparation device, and calculate the total moisture loss rate L M of the total moisture test samples according to the performance test regulations of the combined coal crushing and splitting sample preparation device for thermal power plants DL / T1339, and the unit is %.

[0035] Step 3: Weigh the total moisture sample prepared in the second step and send it to the laboratory. After receiving the total moisture sample, weigh and record it. The total moisture loss rate during transportation and storage is recorded as M1, in %, and M1 does not exceed 1.0%;

[0036] Step 4: Determine the total moisture value (i.e., test value) of the total moisture sample according to the determination method of total moisture in coal in GB / T211. t0 , the unit is %;

[0037] Step 5: Calculate the total moisture loss correction of the coal mining and processing process in the thermal power plant according to the total moisture loss value in the first step, the total moisture loss rate of the total moisture sample in the second step, the total moisture loss rate recorded in the third step, and the total moisture value of the total moisture sample in the fourth step. Correct the test coal sample according to the total moisture loss correction of the coal mining and processing process in the thermal power plant. The total moisture value M of the test coal sample after the total moisture loss correction t,A for:

[0038]

[0039] Where: M1 is the total moisture loss rate of the prepared sample during transportation and storage to the laboratory, in %;

[0040] L M ——Total moisture loss rate of the sample prepared by the crushing and reduction combined sample preparation equipment, in %;

[0041] M t0 ——The total moisture value of the total moisture sample measured according to GB / T211, the unit is %;

[0042] ——The average value of the difference in total moisture loss test, in %;

[0043] s d ——standard deviation of the difference in total water loss test;

[0044] n p - the number of test logs of the total water loss test;

[0045] t β ——Under the 95% confidence probability, the degrees of freedom found in the t value table are (n p -1) is the one-tailed t value.

[0046] Example 1

[0047] The calculation method for the total moisture loss correction of coal sample A in a power plant during the coal mining and processing process is as follows:

[0048] 1) First step: Select the incoming test coal sample A, take the test coal sample using a mechanical sampling and sample preparation device, conduct a total moisture loss test according to GB / T 19494.3, and the number of test pairs is n p = 20, and the standard deviation of the difference is s d = 0.40, and the average value of the difference is

[0049] 2) Second step: Prepare the total moisture test sample from the test coal sample taken by the mechanical sampling and sample preparation device using a combined crushing and sample reduction equipment, and calculate the total moisture loss rate L according to DL / T 1339 M = 3.12%, and the unit is %;

[0050] 3) Third step: Weigh the total moisture test sample prepared in step 2) and send it to the laboratory. After receiving the total moisture test sample, weigh and record it, and record the total moisture loss rate during transportation and storage as M1 = 0.45%;

[0051] 4) Fourth step: Determine the total moisture value M of the total moisture test sample according to GB / T 211 t0 = 13.6%;

[0052] 5) Fifth step: The total moisture value M of coal sample A after total moisture loss correction t,A is:

[0053]

[0054] That is, after the total moisture loss correction calculation in the coal sampling, preparation, and analysis process, the total moisture value of the incoming coal A is in the range of (14.62 - 14.92)%.

[0055] The present invention has the following advantages:

[0056] First, the total moisture loss correction calculation method takes comprehensive factors into account, including the total moisture loss factors of the sampling equipment, sample preparation equipment, and transportation and storage processes;

[0057] Second, the parameters used in the calculation method are easily obtainable. The performance test data of the mechanical sampling and sample preparation device and the combined crushing and sample reduction equipment can be applied to the correction calculation; when there are many coal samples that need total moisture correction, the required parameters can be obtained through the relevant standard test methods described in this method;

[0058] Third, this method is simple to calculate. The total moisture correction calculation result is the range of the total moisture value of the raw coal sample with a 95% confidence probability, and the calculation result has strong practical applicability and reliability.

[0059] The result of the total moisture loss correction calculation in the coal sampling, preparation, and analysis process by this method is accurate, reliable, convenient and fast, and has high practical guiding significance.

[0060] The above description is only for the best embodiments of the present invention, but it should not be construed as a limitation on the claims. The present invention is not limited to the above embodiments, and its specific structure is allowed to vary. Any variations made within the scope of protection of the independent claims of the present invention are within the scope of protection of the present invention.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. A method for calculating the correction of the total moisture loss in the coal sampling, preparation and analysis process of a thermal power plant, characterized in that, The following steps are included: Conduct a total moisture loss test on the test coal sample according to GB / T 19494.3; Prepare a total moisture sample from the test coal sample using a combined crushing and sample reduction equipment, and calculate the total moisture loss rate of the total moisture sample; Weigh the total moisture sample and record the total moisture loss rate during transportation and storage; Determine the total moisture value of the total moisture sample; Calculate the correction of the total moisture loss in the coal sampling, preparation, and analysis process of thermal power plants based on the total moisture loss rate of the total moisture sample, record the total moisture loss rate during transportation and storage, and the total moisture value of the total moisture sample; the total moisture value M of the test coal sample after correction t,A is as follows: Where: M1 - the total moisture loss rate during transportation and storage when the prepared total moisture sample is sent to the laboratory; L M ——Total moisture loss rate of the total moisture sample prepared by the combined sample preparation equipment for crushing and splitting M t0 — Total moisture value of the total moisture sample determined according to GB / T 211; ——Average difference value of total moisture loss test; s d —— Standard deviation of difference in total moisture loss test; n p —— The number of test pairs for the total moisture loss test; t β —— one-tailed t value at the degree of freedom of (n p - 1) obtained from the t value table at 95% confidence probability; The test coal sample is obtained through a mechanical sampling and sample preparation device; Calculate the total moisture loss rate according to the method of DL / T 1339.

2. The method for calculating the correction of the total moisture loss in the coal sampling, preparation and analysis process of a thermal power plant according to claim 1, characterized in that, When conducting the total moisture loss test, the number of test pairs is n p = 20, and the standard deviation of the differences is s d = 0.40, and the average value of the differences is 3. The method for calculating the correction of the total moisture loss in the coal sampling, preparation and analysis process of a thermal power plant according to claim 1, characterized in that, The recorded total moisture loss rate does not exceed 1.0%.

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