Boiler soot blowing method and device

Abstract

The invention relates to a boiler soot blowing method and equipment, and the method comprises the following steps: obtaining an operation load, a total coal as fired quantity and denitration system inlet flue gas temperature rise in real time, searching on a total coal as fired quantity-denitration system inlet flue gas temperature rise fitting curve of different load sections, and carrying out soot blowing operation after a set condition is met; the generation process of the total coal as fired quantity-denitration system inlet flue gas temperature rise fitting curve of each load section is as follows: under the steady-state load of a certain load section, after the last soot blowing is completed, the same coal type is used for continuous combustion, and the total coal as fired quantity generated data set when the denitration system inlet flue gas rises by N DEG C every time is recorded, fitting to obtain a total coal as fired quantity-denitration system inlet flue gas temperature rise fitting curve corresponding to the load section; the set conditions comprise a first judgment condition set based on the total as-fired coal quantity and a second judgment condition set based on the flue gas temperature rise at the inlet of the denitration system. Compared with the prior art, a reasonable soot blowing scheme can be provided in real time, and production activity safety is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of coal-fired boiler equipment control, and in particular relates to a boiler soot blowing method and equipment. Background Art

[0002] When coal-fired power plant boilers are in long-term operation, dust and coking will accumulate on the heating surface, which will not only deteriorate the heat transfer effect, but may also cause re-combustion accidents in the tail flue due to the long-term accumulation of combustibles. In order to clean the heating surface and ensure the safe operation of the boiler, the boiler needs to be soot-blown. Traditional coal-fired power plants adopt the soot-blowing mode and strategy of "on-time and on-shift" + "sequential soot-blowing". The above soot-blowing method cannot achieve the effect of precise soot-blowing on demand, and may cause "over-blowing" or "under-blowing" problems, thus affecting the safe operation of the unit.

[0003] At present, researchers have conducted a lot of research on boiler heating surface pollution status monitoring and sootblowing optimization, proposed a variety of heating surface pollution status monitoring methods and developed corresponding online monitoring and sootblowing optimization systems, which can be applied to different types of coal-fired boilers. For example, Chinese patent application 202010502918.1 proposed a furnace sootblowing method, which fits the pollution rate curve during ash accumulation and the pollution rate during sootblowing with historical furnace pollution data to obtain a sootblowing optimization model, solve the upper and lower limits of the critical pollution rate, the reasonable ash accumulation time and the sootblowing time, and then control the start and stop of the furnace sootblowing. However, the above method uses historical operating messy data as samples for data analysis, and does not combine the actual operating conditions of the combustion mechanism for analysis. There may be a large gap between the actual application and the ideal state. For another example, Chinese patent application 202110777782.X proposes an intelligent sootblowing control method, system and medium based on multi-dimensional evaluation factors, selects multiple boiler operating parameters as evaluation factors for selecting sootblowers, and groups each evaluation factor into priority levels according to the impact of each evaluation factor on boiler safety, the impact on economic operation, and the degree of correlation with heating surface contamination. The number of evaluation factors in each priority level whose values ​​are not within the normal state range is counted, and the number of evaluation factors in each priority level whose values ​​are not within the normal state range is used to determine whether a sootblower is needed for sootblowing. The above method has the phenomenon of too many choices and mixed coupling in the selection of online parameters. At the same time, since there is no obvious breakthrough in the relevant monitoring technology of the pollution state of the heating surface in the coal-fired boiler, similar systems have not been actually put into operation in most power plants. Therefore, it is necessary to design a simple boiler sootblowing method that can provide a reasonable sootblowing plan in real time to ensure the safety of production activities. Summary of the invention

[0004] The purpose of the present invention is to provide a boiler sootblowing method and device in order to overcome the defects of the above-mentioned prior art, which can provide a reasonable sootblowing plan in real time and ensure the safety of production activities.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] The present invention provides a boiler sootblowing method, comprising the following steps:

[0007] Obtain the operating load, total coal quantity fed into the furnace and the rise in flue gas temperature at the inlet of the denitrification system in real time, search on the fitting curve of total coal quantity fed into the furnace - rise in flue gas temperature at the inlet of the denitrification system in different load sections, and perform soot blowing operation when the set conditions are met;

[0008] Among them, the generation process of the fitting curve of the total coal input in each load section and the flue gas temperature rise at the inlet of the denitrification system is as follows:

[0009] Under a steady-state load in a certain load section, after the last soot blowing is completed, the same type of coal is used for continuous combustion, and the total amount of coal entering the furnace is recorded when the flue gas at the inlet of the denitrification system rises by N°C, and a data set is generated. Based on the data set, fitting is performed to obtain a fitting curve of the total amount of coal entering the furnace-the rise in flue gas temperature at the inlet of the denitrification system corresponding to the load section;

[0010] The set conditions include a first determination condition set based on the total amount of coal fed into the furnace and a second determination condition set based on the rise in the flue gas temperature at the inlet of the denitrification system.

[0011] Furthermore, when different types of coal are used in different load sections, the total amount of coal entering the furnace recorded when the flue gas at the inlet of the denitrification system rises N°C is normalized by the following formula:

[0012]

[0013] Among them, Q1 and Q are the total amount of coal entering the furnace before and after normalization, A and A1 are the received basic ash content of commonly used coal and uncommon coal, respectively.

[0014] Furthermore, the methods used for fitting based on the data set include regression analysis and function fitting.

[0015] Furthermore, the specific process of performing the soot blowing operation when the first determination condition is met is as follows:

[0016] When the ratio of the total coal quantity input into the furnace obtained in real time to the total coal quantity input into the furnace corresponding to the rise of 10°C in the flue gas temperature at the inlet of the denitrification system in the fitting curve reaches the first set threshold, a contamination warning is issued and soot blowing operation is performed after 10 minutes.

[0017] Furthermore, the specific process of performing the soot blowing operation when the second determination condition is met is as follows:

[0018] When the real-time flue gas temperature rise at the denitrification system inlet reaches the second set threshold, a contamination warning is issued and soot blowing is performed after 10 minutes.

[0019] The present invention also provides a boiler sootblowing device, comprising a boiler data acquisition module, a data fitting module and a monitoring and early warning module.

[0020] The boiler data acquisition module is used to obtain the operating load, the total amount of coal entering the boiler and the rise in flue gas temperature at the inlet of the denitrification system in real time;

[0021] The data fitting module is used to generate a fitting curve of the total amount of coal fed into the furnace and the rise in flue gas temperature at the inlet of the denitrification system in different load sections. The generation process of the fitting curve of the total amount of coal fed into the furnace and the rise in flue gas temperature at the inlet of the denitrification system in each load section is as follows: under a steady-state load in a certain load section, after the last soot blowing is completed, the same type of coal is used for continuous combustion, and the total amount of coal fed into the furnace is recorded every time the flue gas at the inlet of the denitrification system rises by N°C, and a data set is generated. Fitting is performed based on the data set to obtain a fitting curve of the total amount of coal fed into the furnace and the rise in flue gas temperature at the inlet of the denitrification system corresponding to the load section;

[0022] The monitoring and early warning module is used to search on the fitting curve of total coal input - flue gas temperature rise at the inlet of the denitrification system for different load sections generated by the data fitting module according to the real-time data acquired by the boiler data acquisition module, and perform soot blowing operation after the set conditions are met. The set conditions include a first judgment condition set based on the total coal input and a second judgment condition set based on the flue gas temperature rise at the inlet of the denitrification system.

[0023] Furthermore, when different types of coal are used in different load sections, the total amount of coal entering the furnace recorded when the flue gas at the inlet of the denitrification system rises N°C is normalized by the following formula:

[0024]

[0025] Among them, Q1 and Q are the total amount of coal entering the furnace before and after normalization, A and A1 are the received basic ash content of commonly used coal and uncommon coal, respectively.

[0026] Furthermore, the methods used for fitting based on the data set include regression analysis and function fitting.

[0027] Furthermore, the specific process of performing the soot blowing operation when the first determination condition is met is as follows:

[0028] When the ratio of the total coal quantity input into the furnace obtained in real time to the total coal quantity input into the furnace corresponding to the rise of 10°C in the flue gas temperature at the inlet of the denitrification system in the fitting curve reaches the first set threshold, a contamination warning is issued and soot blowing operation is performed after 10 minutes.

[0029] Furthermore, the specific process of performing the soot blowing operation when the second determination condition is met is as follows:

[0030] When the real-time flue gas temperature rise at the denitrification system inlet reaches the second set threshold, a contamination warning is issued and soot blowing is performed after 10 minutes.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention proposes a boiler sootblowing method. First, the operating load, the total amount of coal fed into the furnace and the rise in flue gas temperature at the inlet of the denitrification system are obtained in real time. Then, a search is performed on the fitting curve of the total amount of coal fed into the furnace and the rise in flue gas temperature at the inlet of the denitrification system in different load sections, and the sootblowing operation is performed after the set conditions are met. Specifically, under a steady-state load in a certain load section, after the last sootblowing is completed, the same type of coal is used for continuous combustion, and the total amount of coal fed into the furnace is recorded every time the flue gas at the inlet of the denitrification system rises by N°C. A data set is generated and fitted to obtain the fitting curve of the total amount of coal fed into the furnace and the rise in flue gas temperature at the inlet of the denitrification system corresponding to the load section. The setting conditions include setting the total amount of coal fed into the furnace based on the total amount of coal fed into the furnace. The first judgment condition, that is, when the ratio of the total coal input into the furnace obtained in real time to the total coal input into the furnace corresponding to the temperature rise of 10°C at the inlet flue gas temperature of the denitrification system in the fitting curve reaches the first set threshold value, a contamination warning is issued, and soot blowing operation is performed after 10 minutes; the set conditions also include a second judgment condition set based on the temperature rise of the inlet flue gas temperature of the denitrification system, that is, when the temperature rise of the inlet flue gas temperature of the denitrification system obtained in real time reaches the second set threshold value, a contamination warning is issued, and soot blowing operation is performed after 10 minutes; the above method only needs to collect three key parameters of the boiler, and has the advantages of accurate judgment, low cost, convenient implementation, easy promotion, etc., which is conducive to the safe and stable operation of the boiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the process of the present invention;

[0034] Figure 2 This is the fitting curve of total coal input under 350MW load - flue gas temperature rise at the inlet of denitrification system. DETAILED DESCRIPTION

[0035] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0036] Example:

[0037] This embodiment provides a boiler soot blowing method, such as Figure 1 As shown, the following steps are included:

[0038] S1. Generate the fitting curve of total coal input amount and flue gas temperature rise at the inlet of denitrification system in different load sections. The specific process is as follows:

[0039] Due to the complex and changeable operation state of the boiler, in the actual operation process, after soot blowing in multiple stable load sections (600MW, 550MW, 500MW, 450MW, 400MW, 350MW, 300MW, 250MW, 200MW), the temperature was observed to be stable and the temperature can reach the lowest value and stable state 30 minutes after the soot blowing. Therefore, the load rate accumulation and the total amount of coal entering the furnace Q are accumulated starting from the state 30 minutes after the soot blowing. Under the steady-state load of a certain load section, 30 minutes after the last soot blowing, the same type of coal is used for continuous combustion, and the total amount of coal entering the furnace when the flue gas at the inlet of the denitrification system rises by 10°C is recorded. The data set is generated and fitted by quadratic function to obtain the fitting curve of the total amount of coal entering the furnace - the rise in flue gas temperature at the inlet of the denitrification system corresponding to the load section, such as Figure 2 As shown, the horizontal axis of the curve is the temperature increase, and the vertical axis is the total amount of coal entering the furnace.

[0040] In particular, when different types of coal are used in different load sections, the total amount of coal entering the furnace recorded when the flue gas at the inlet of the denitrification system rises N°C is normalized by the following formula:

[0041]

[0042] Among them, Q1 and Q are the total amount of coal entering the furnace before and after normalization, A and A1 are the received basic ash content of commonly used coal and uncommon coal, respectively.

[0043] S2. Obtain the current operating load, total coal quantity fed into the furnace and the flue gas temperature rise at the inlet of the denitrification system in real time.

[0044] S3. Search on the fitting curve of the total coal quantity fed into the furnace in each load section - the rise in flue gas temperature at the inlet of the denitrification system, and perform soot blowing operation after the set conditions are met.

[0045] The setting conditions include a first judgment condition based on the total amount of coal entering the furnace and a second judgment condition based on the rise in the flue gas temperature at the inlet of the denitrification system. The specific process of soot blowing when the first judgment condition is met is as follows: when the ratio of the total amount of coal entering the furnace obtained in real time to the total amount of coal entering the furnace corresponding to the rise in the flue gas temperature at the inlet of the denitrification system of 10°C in the fitting curve reaches the first set threshold value (95%), a contamination warning is issued, and soot blowing is performed after 10 minutes. The specific process of soot blowing when the second judgment condition is met is as follows: when the rise in the flue gas temperature at the inlet of the denitrification system obtained in real time reaches the second set threshold value (9°C), a contamination warning is issued, and soot blowing is performed after 10 minutes.

[0046] In a preferred embodiment, taking into account that during actual operation, the allowable temperature of the denitrification system catalyst is 300°C, and the flue gas temperature at the inlet of the denitrification system is relatively low when the unit is under low load, it is set to stop the contamination warning and soot blowing action when the flue gas temperature at the denitrification inlet is lower than 310°C.

[0047] The above method only needs to collect, calculate and analyze data under the actual stable operating conditions of the boiler based on three key data: the existing operating load of the boiler, the total amount of coal entering the boiler, and the rise in flue gas temperature at the inlet of the denitrification system. The overall contamination state of the boiler can be judged by comparing the actual value with the benchmark value under the actual boiler operating state. It has the advantages of accurate judgment, low cost, convenient implementation and easy promotion. The soot blowing method of the power plant can be guided according to the contamination state, which is beneficial to the safe and stable operation of the boiler.

[0048] If the above method is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0049] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A boiler sootblowing method, characterized in that: The following steps are involved: Obtain the operating load, total coal quantity fed into the furnace and the rise in flue gas temperature at the inlet of the denitrification system in real time, search on the fitting curve of total coal quantity fed into the furnace - rise in flue gas temperature at the inlet of the denitrification system in different load sections, and perform soot blowing operation when the set conditions are met; Among them, the generation process of the fitting curve of the total coal input in each load section and the flue gas temperature rise at the inlet of the denitrification system is as follows: Under a steady-state load in a certain load section, after the last soot blowing is completed, the same type of coal is used for continuous combustion, and the total amount of coal entering the furnace is recorded when the flue gas at the inlet of the denitrification system rises by N°C, and a data set is generated. Based on the data set, fitting is performed to obtain a fitting curve of the total amount of coal entering the furnace-the rise in flue gas temperature at the inlet of the denitrification system corresponding to the load section; The set conditions include a first determination condition set based on the total amount of coal fed into the furnace and a second determination condition set based on the rise in the flue gas temperature at the inlet of the denitrification system.

2. A boiler sootblowing method according to claim 1, characterized in that: When different types of coal are used in different load sections, the total amount of coal entering the furnace recorded when the flue gas at the inlet of the denitrification system rises N°C is normalized by the following formula: Among them, Q1 and Q are the total amount of coal entering the furnace before and after normalization, A and A1 are the received basic ash content of commonly used coal and uncommon coal, respectively.

3. A boiler sootblowing method according to claim 1, characterized in that: The methods used for fitting based on the data set include regression analysis and function fitting.

4. A boiler sootblowing method according to claim 1, characterized in that: The specific process of performing the soot blowing operation when the first determination condition is met is as follows: When the ratio of the total coal quantity input into the furnace obtained in real time to the total coal quantity input into the furnace corresponding to the rise of 10°C in the flue gas temperature at the inlet of the denitrification system in the fitting curve reaches the first set threshold, a contamination warning is issued and soot blowing operation is performed after 10 minutes.

5. A boiler sootblowing method according to claim 1, characterized in that: The specific process of performing the soot blowing operation when the second determination condition is met is as follows: When the real-time flue gas temperature rise at the denitrification system inlet reaches the second set threshold, a contamination warning is issued and soot blowing is performed after 10 minutes.

6. A boiler sootblowing device, characterized in that: Including boiler data acquisition module, data fitting module and monitoring and early warning module, The boiler data acquisition module is used to obtain the operating load, the total amount of coal entering the boiler and the rise in flue gas temperature at the inlet of the denitrification system in real time; The data fitting module is used to generate a fitting curve of the total amount of coal fed into the furnace and the rise in flue gas temperature at the inlet of the denitrification system in different load sections. The generation process of the fitting curve of the total amount of coal fed into the furnace and the rise in flue gas temperature at the inlet of the denitrification system in each load section is as follows: under a steady-state load in a certain load section, after the last soot blowing is completed, the same type of coal is used for continuous combustion, and the total amount of coal fed into the furnace is recorded every time the flue gas at the inlet of the denitrification system rises by N°C, and a data set is generated. Fitting is performed based on the data set to obtain a fitting curve of the total amount of coal fed into the furnace and the rise in flue gas temperature at the inlet of the denitrification system corresponding to the load section; The monitoring and early warning module is used to search on the fitting curve of total coal input - flue gas temperature rise at the inlet of the denitrification system for different load sections generated by the data fitting module according to the real-time data acquired by the boiler data acquisition module, and perform soot blowing operation after the set conditions are met. The set conditions include a first judgment condition set based on the total coal input and a second judgment condition set based on the flue gas temperature rise at the inlet of the denitrification system.

7. A boiler sootblowing device according to claim 6, characterized in that: When different types of coal are used in different load sections, the total amount of coal entering the furnace recorded when the flue gas at the inlet of the denitrification system rises N°C is normalized by the following formula: Among them, Q1 and Q are the total amount of coal entering the furnace before and after normalization, A and A1 are the received basic ash content of commonly used coal and uncommon coal, respectively.

8. The boiler sootblowing equipment according to claim 6, characterized in that: The methods used for fitting based on the data set include regression analysis and function fitting.

9. A boiler sootblowing device according to claim 6, characterized in that: The specific process of performing the soot blowing operation when the first determination condition is met is as follows: When the ratio of the total coal quantity input into the furnace obtained in real time to the total coal quantity input into the furnace corresponding to the rise of 10°C in the flue gas temperature at the inlet of the denitrification system in the fitting curve reaches the first set threshold, a contamination warning is issued and soot blowing operation is performed after 10 minutes.

10. The boiler sootblowing equipment according to claim 6, characterized in that: The specific process of performing the soot blowing operation when the second determination condition is met is as follows: When the real-time flue gas temperature rise at the denitrification system inlet reaches the second set threshold, a contamination warning is issued and soot blowing is performed after 10 minutes.

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