CN115993435A - Method for improving accuracy of coal quality of boiler coal blending by utilizing primary mixed coal physical property analysis technology - Google Patents

Abstract

The invention discloses a method for improving the accuracy of coal quality of boiler coal blending by utilizing an initial mixed coal physical property analysis technology, which comprises the following steps: s1, preparing a standard coal sample for analysis; s2, analyzing the reflectivity of the primary mixed coal sample: analyzing the structure of the primary mixed coal of the power plant by means of a lithofacies analysis method; s3, carrying out industrial analysis and assay on the primary mixed coal samples, and respectively detecting the components and various indexes of different primary mixed coal samples; s4, performing elementary analysis and assay on the primary mixed coal sample; s5, combining industrial analysis and element analysis data of the fire coal, determining the characteristic relation of the primary mixed coal, forming the combustion physical property characteristics of the primary mixed coal, and obtaining basic information of the primary mixed coal; s6, formulating a blending scheme suitable for the boiler according to the accurate primary mixing coal quality basic information. The invention improves blending coordination, meets the combustion requirement of the boiler, solves the safety problem of the boiler, improves the accuracy of coal quality of blending coal of the coal-fired boiler, reduces production cost and improves the safety and stability of the unit.

Description

A method to improve the accuracy of boiler coal blending coal quality by using the analysis technology of primary mixed coal physical properties

technical field

The invention relates to the technical field of safe operation of coal-fired boilers, and more specifically relates to a method for improving the accuracy of coal quality of coal mixed in boilers by utilizing the physical property analysis technology of primary mixed coal.

Background technique

Coal price directly determines the operation status of coal-fired power plants. Under the condition of fixed on-grid electricity price, coal price is the key to the profit of coal-fired power plants. Lower overall fuel costs. Many coal-fired power plant boilers have been in the combustion state of non-design coal for a long time. The boiler design of coal-fired power plants is based on the design coal and check coal. If the design coal is used, the boiler performance is good; but if it is not Designing the type of coal will make the combustion effect worse, the operation stability will decrease, the low load peak regulation will be difficult, the thermal efficiency of the boiler will decrease, coking, slagging, overheating of the superheater will occur, the desulfurization system will not adapt, and the pollution discharge will exceed the standard. Because the coal quality deviates from the designed coal type, the coal heat utilization rate of the boiler is reduced, resulting in huge energy waste. Under the multiple pressures of complex and changeable coal types, safe and efficient production, and national policies, more and more coal-fired power plants in China have carried out blending coal blending to alleviate many problems caused by boilers burning non-design coal types.

In order to reduce fuel costs, coal-fired power plants generally adopt the blending mode of coal blending. However, in the traditional blending method, the basic data source of coal quality used is the information of a single type of coal, and the blending calculation basis is based on Each single coal type is calculated by algorithm to obtain the blending result. However, the actual incoming coal of the power plant is not a single type of coal or the direct supply coal source of the same coal mine. Most of the incoming coal has been blended with a single type of coal for the first time to meet the requirements of several numerical parameters such as calorific value and sulfur content. The actual problem that a single coal source cannot be accurately traced will eventually lead to unsatisfactory blending results, which will lead to a series of problems such as low boiler operation efficiency, coking in the furnace, high-temperature corrosion, overtemperature of the heating surface tube wall, and high energy consumption for desulfurization and denitrification.

In view of the fact that the current coal blending has a complex incoming coal structure, most of the incoming coal has been initially mixed with different single coal types or multiple coal types, resulting in the practical problem that the coal quality cannot be accurately traced, and it is necessary to improve the coal combustion. Research on coal quality accuracy of blended coal in power plants.

Contents of the invention

The technical problem to be solved in the present invention is to provide a method for improving the accuracy of boiler coal blending coal quality by using the analysis technology of the primary coal mixture, so as to solve the problem that the actual power plant incoming coal has been initially blended by a single coal type, and the single coal source cannot Accurate traceability leads to unsatisfactory blending results and causes problems in boiler operation safety.

In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows.

The method for improving the accuracy of boiler coal blending coal quality by using the primary mixed coal physical property analysis technology includes the following steps:

S1, make the standard coal sample available for analysis;

S2. Reflectance analysis of primary mixed coal samples: relying on petrographic analysis methods to analyze the structure of primary mixed coal in power plants;

S3. Industrial analysis and testing of primary mixed coal samples to detect the components and various indicators of different primary mixed coal samples;

S4. Elemental analysis and testing of primary mixed coal samples;

S5. Combining the coal-fired industrial analysis and elemental analysis data, determine the characteristic relationship of the primary mixed coal, form the combustion physical properties of the primary mixed coal, and obtain the basic information of the primary mixed coal quality;

S6. Formulate a blending scheme suitable for the boiler according to the accurate primary coal quality basic information.

To further optimize the technical solution, in the step S2, analyzing the initial mixed coal structure of the power plant includes the following aspects:

Identify the type of primary coal mixture;

Judging whether the coal sample is a single mixed coal or multiple mixed coals;

Analyze the composition ratio of different coal types in coal samples.

To further optimize the technical solution, in the step S2, the primary mixed coal structure is mainly judged based on the average maximum reflectance Rmax of the tested coal vitrinite and the distribution map of the vitrinite reflectance, and the primary mixed coal structure is judged by the average maximum reflectance Rmax Coal type, the metamorphic degree of coal and the type of mixed coal can be judged by the vitrinite reflectance distribution map.

To further optimize the technical solution, the primary mixed coal categories include: anthracite, lean coal, lean coal, lean coal, coking coal, fat coal, gas fat coal, gas coal, weakly sticky coal, long-flame coal, and lignite.

To further optimize the technical scheme, the basis for judging the coal blending type of coal through the vitrinite reflectance distribution map is:

The number of notches is counted from the vitrinite reflectance distribution map, according to the standard deviation of vitrinite reflectance and the number of notches in the reflectance frequency distribution map, and according to the provisions of the coding system of commercial coal reflectance distribution map, it corresponds to the coal blending type of commercial coal Make a judgment.

To further optimize the technical solution, in the step S3, the moisture, volatile matter, ash and fixed carbon components of different primary mixed coal samples, as well as indicators of sulfur content and calorific value are detected respectively through coal-fired industrial analysis.

Due to the adoption of the above technical solutions, the technological progress achieved by the present invention is as follows.

The present invention uses the lithofacies analysis method and according to the average maximum reflectance and distribution map of vitrinite to analyze the structure of primary mixed coal in the power plant, and at the same time combines the coal-fired industrial analysis and elemental analysis data to determine the characteristics of the primary mixed coal such as volatile matter and ash melting point relationship, form the combustion physical properties of the initial mixture coal, obtain the basic information of the initial mixture coal quality, and use it to guide the blending scheme of coal blending, improve the blending rationality, meet the boiler combustion needs, solve the boiler safety problem, and improve the quality of coal-fired boilers. The accuracy of coal quality by blending coal types reduces production costs and improves the safety and stability of the unit.

The invention effectively alleviates the boiler combustion safety problems caused by unreasonable mixed combustion due to inaccurate coal quality, such as coking in the furnace, high-temperature corrosion, overtemperature of the pipe wall, and the like.

The invention reduces the amount of pollutants generated by boilers and relieves the pressure of flue gas pollutants by performing reasonable blending based on accurate coal quality data.

The invention improves the economical efficiency of the boiler, widens the adaptable range of coal types, makes the purchasing of coal more flexible, and reduces the cost of power generation by performing reasonable blending based on accurate coal quality data.

Description of drawings

Fig. 1 is a schematic flow sheet of the present invention;

Fig. 2 is a typical distribution diagram corresponding to the encoding system of commercial coal reflectance distribution diagram according to the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

The method for improving the accuracy of boiler coal blending coal quality by using the primary mixed coal physical property analysis technology includes the following steps:

S1. Carry out standardized sampling for different primary mixed coals used for blending in coal-fired boilers, and unify the group numbers to make standard coal samples available for analysis.

S2. Analysis of the reflectance of the primary mixed coal sample. The invention uses a lithofacies analysis method to analyze the structure of primary mixed coal in a power plant according to the average maximum reflectance and distribution diagram of vitrinite. The lithofacial analysis method uses a lithofacies analyzer to analyze and distinguish the structure of primary mixed coal.

In step S2, analyzing the initial coal mix structure of the power plant includes the following aspects:

Identify the type of primary coal mixture, which includes anthracite, lean coal, lean coal, lean coal, coking coal, fat coal, gas fat coal, gas coal, weakly sticky coal, long-flame coal, lignite, etc.

Determine whether the coal sample is a single coal blend or multiple coal blends.

Analyze the composition ratio of different coal types in coal samples.

Relying on the petrographic analysis method and using the petrographic analyzer to analyze and identify the structure of the primary mixed coal, it is mainly judged based on the two indicators of the vitrinite of the mixed coal. The primary mixed coal structure is mainly judged based on the average maximum reflectance Rmax of the vitrinite and the distribution map of the vitrinite reflectance of the tested coal mixture. Judging the metamorphic degree of coal and the type of mixed coal.

1. Average maximum reflectance Rmax

The principle of vitrinite reflectance test: a beam of incident light is irradiated on the polished surface of the coal rock optical film, and the 546nm reflected light on the vitrinite particles enters the photoelectric converter, and the optical signal is converted into a weak electrical signal, which is amplified by the instrument After that, it is measured by precision instruments, and then compared with the data obtained by the standard substance, the result is the vitrinite reflectance, which is expressed by Rmax.

The corresponding relationship between the maximum reflectance average value Rmax and the coal type is shown in the following table:

<![CDATA[R^o_max/%]]> Possible coal types (arranged by frequency of occurrence) <0.5 lignite, long flame coal 0.5～<0.6 Long flame coal, non-stick coal, gas coal 0.6～<0.7 Gas coal, long flame coal, non-stick coal, gas fertilizer coal 0.7～<0.8 Gas coal, gas fat coal, weak caking coal, non-caking coal, 1/2 medium caking coal 0.8～<0.9 1/3 coking coal, gas coal, weak caking coal, non-caking coal, fat coal, gas fat coal 0.9～<1.0 1/3 coking coal, fat coal, gas coal, 1/2 medium caking coal, gas fat coal 1.0～<1.1 Fat coal, 1/3 coking coal 1.1～<1.2 Fat coal, 1/3 coking coal, coking coal 1.2～<1.3 Coking coal, fat coal, 1/3 coking coal 1.3～<1.4 coking coal, fat coal 1.4～<1.5 coking coal 1.5～<1.6 coking coal, lean coal, lean coal 1.6～<1.7 lean coal, coking coal, lean coal 1.7～<1.8 lean coal, lean coal, coking coal, lean coal 1.8～<1.9 lean coal, lean coal, lean coal 1.9～<2.0 lean coal, lean coal, lean coal 2.0～<2.5 lean coal >=2.5 anthracite, lean coal

2. Vitrinite reflectance distribution map

According to the vitrinite reflectance and distribution map of coal, the metamorphic degree of coal and its mixed coal status can be judged. The image analysis method is based on the correlation between the gray level of the image and the reflectance, and the reflectance of all components in the coal including the vitrinite is measured through the gray scale, and the reflectance of the non-vitrinite is removed by a special processing method to obtain The average reflectance of vitrinite and its distribution map. During the measurement, the coal sample is first made into a pulverized coal light sheet, and the standard sheet is used to calibrate the instrument before the measurement.

The drawing process of the vitrinite reflectance distribution diagram of the present invention is as follows: take the reflectivity interval of 0.05% as the half order, respectively count the number of measuring points in each interval and calculate the frequency (f). Taking the frequency as the vertical axis and the random reflectance (Rran) as the horizontal axis, the vitrinite reflectance distribution diagram is drawn.

According to the vitrinite reflectance distribution map, the basis for judging the coal blending type of coal is: the "notch number" is counted from the vitrinite reflectance distribution map with a vitrinite reflectance interval of 0.05%, and according to the vitrinite reflectance standard The difference and the number of notches in the frequency distribution map of reflectance, and according to the provisions of the coding system of the reflectance distribution map of commercial coal shown in Table 1, are used to distinguish the type of mixed coal of commercial coal. The corresponding typical distribution diagram of the commercial coal reflectance distribution diagram coding system is shown in Fig. 2.

Table 1 Coding system of commercial coal reflectance distribution map

Note: The reflectance distribution map with the characteristics of code 1 may also be a single seam coal of high-rank bituminous coal and anthracite.

S3. Industrial analysis and testing of primary mixed coal samples. Through industrial analysis of coal combustion, the moisture, volatile matter, ash, fixed carbon and other components of different primary mixed coal samples, as well as various indicators such as sulfur content and calorific value, were detected.

S4. Elemental analysis and testing of primary mixed coal samples. Detect and analyze the element content of different primary mixed coal samples, including conventional C, H, O, N, S, Al, Si, Fe, Ca and other element contents, and also detect trace elements in coal including Ti, Na, K, etc. Elemental analysis is an important indicator for studying the degree of metamorphism of coal, calculating the calorific value of coal, and estimating the carbonization products of coal. It is also the basis for calorie calculation when coal is used as fuel in industry.

S5. Analysis of the combustion properties of primary mixed coal samples. Relying on petrographic analysis methods, analyze the coal types and proportions of primary mixed coal in power plants, and combine coal industry analysis and elemental analysis data to determine the volatile content and ash melting point of primary mixed coal, etc. Characteristic relationship, forming the combustion physical properties of the primary mixture coal, and obtaining the basic information of the primary mixture coal quality.

S6. According to the accurate primary coal quality basic information, provide more accurate coal quality data support for coal blending, and then formulate a safe, stable and economical blending plan for boilers according to different boiler combustion methods and characteristics and blending requirements.

The present invention uses the lithofacies analysis method and according to the average maximum reflectance and distribution map of vitrinite to analyze the structure of primary mixed coal in the power plant, and at the same time combines the coal-fired industrial analysis and elemental analysis data to determine the characteristics of the primary mixed coal such as volatile matter and ash melting point relationship, form the combustion physical properties of the initial mixture coal, obtain the basic information of the initial mixture coal quality, and use it to guide the blending scheme of coal blending, improve the blending rationality, meet the boiler combustion needs, solve the boiler safety problem, and improve the quality of coal-fired boilers. The accuracy of coal quality by blending coal types reduces production costs and improves the safety and stability of the unit.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (6)

1. The method for improving the accuracy of boiler coal blending coal quality by using the primary mixed coal physical property analysis technology is characterized in that it comprises the following steps: S1, make the standard coal sample available for analysis; S2. Reflectance analysis of primary mixed coal samples: relying on petrographic analysis methods to analyze the structure of primary mixed coal in power plants; S3. Industrial analysis and testing of primary mixed coal samples to detect the components and various indicators of different primary mixed coal samples; S4. Elemental analysis and testing of primary mixed coal samples; S5. Combining the coal-fired industrial analysis and elemental analysis data, determine the characteristic relationship of the primary mixed coal, form the combustion physical properties of the primary mixed coal, and obtain the basic information of the primary mixed coal quality; S6. Formulate a blending scheme suitable for the boiler according to the accurate primary coal quality basic information. 2. The method according to claim 1, wherein the method for improving the accuracy of boiler coal blending coal quality by using the primary coal mixture analysis technology, is characterized in that, in the step S2, analyzing the initial mixture coal structure of the power plant includes the following aspects: Identify the type of primary coal mixture; Judging whether the coal sample is a single mixed coal or multiple mixed coals; Analyze the composition ratio of different coal types in coal samples. 3. The method according to claim 2, wherein the method for improving the accuracy of boiler coal blending coal quality by using the primary coal blending physical property analysis technology, is characterized in that, in the step S2, the primary blending coal structure is mainly based on the test blended coal vitrinite The average maximum reflectance Rmax and the vitrinite reflectance distribution map are used to judge the initial mixed coal type, and the vitrinite reflectance distribution map is used to judge the degree of coal metamorphism and the mixed coal type. 4. The method according to claim 2 or 3, wherein the method for improving the accuracy of boiler coal blending coal quality by using primary mixed coal physical property analysis technology is characterized in that, the primary mixed coal category includes: anthracite, lean coal, lean coal, Lean coal, coking coal, fat coal, gas fat coal, gas coal, weak sticky coal, long flame coal, lignite. 5. The method according to claim 3 of claim 3, wherein the method for improving the accuracy of boiler coal blending coal quality by using the primary blended coal physical property analysis technology is characterized in that the basis for judging the blended coal category of coal through the vitrinite reflectance distribution diagram is: The number of notches is counted from the vitrinite reflectance distribution map, according to the standard deviation of vitrinite reflectance and the number of notches in the reflectance frequency distribution map, and according to the provisions of the coding system of commercial coal reflectance distribution map, it corresponds to the coal blending type of commercial coal Make a judgment. 6. The method for improving the accuracy of boiler coal blending coal quality by using the primary mixed coal physical property analysis technology according to claim 1, characterized in that, in the step S3, different primary mixed coals are respectively detected through coal-fired industrial analysis The moisture, volatile matter, ash and fixed carbon components of the sample, as well as indicators of sulfur content and calorific value.

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