High-alkali coal combustion control device system and method based on oxygen amount and smoke temperature double adjustment

Abstract

The invention provides a high-alkali coal combustion control device system and method based on oxygen amount and smoke temperature double adjustment. The high-alkali coal combustion control device system comprises an oxygen amount testing module, a smoke temperature testing module and a main combustor secondary air door. The oxygen content testing module is arranged in a combustor area and an economizer outlet in a hearth; the oxygen content testing module in the combustor area and the combustor are arranged at the same height; the smoke temperature testing module is arranged in an SOFA air burner area; the oxygen content testing module and the smoke temperature testing module are both connected with a secondary air door of the main combustor. The positions of the oxygen content testing module and the smoke temperature testing module are reasonably arranged, the oxygen content and the smoke temperature in the coal-fired power generation blending combustion high-alkali coal are finely adjusted in the whole process, the opening degree of a secondary air door is optimized, and coking of a heated surface is restrained.

Description

Technical Field

[0001] The present invention relates to the technical field of boiler optimized operation, and particularly relates to a high-alkali coal combustion control device system and method based on dual regulation of oxygen content and flue gas temperature. Background Art

[0002] In order to reduce fuel costs, coal-fired power generation enterprises blend high-alkali coal (the mass proportion of Na2O in coal ash > 3%) on the basis of the designed coal type. The contents of Na2O and CaO in the coal ash of high-alkali coal reach 3-10 wt% and 20-40 wt% respectively. Blending a large proportion of high-alkali coal easily causes fouling and slagging of the boiler heating surface, affecting the safe and stable operation of the boiler.

[0003] Currently, boilers blending a large proportion of high-alkali coal adopt methods of controlling the oxygen content in the furnace and the flue gas temperature at the furnace outlet to solve problems such as fouling and slagging of the boiler heating surface.

[0004] CN118129170A discloses a boiler flue gas circulation system and method with wide-range adjustable oxygen / temperature, including a boiler, a dust collector, a desulfurization tower, and a chimney connected in sequence. A staged heat exchange component and an air preheater are arranged in the boiler along the gas flow direction. It also includes a circulating flue gas multi-point injection device, including a bottom flue gas lance, a main combustion zone flue gas lance, a reduction zone flue gas lance, a bottom of the screen flue gas lance, and a flue gas circulation pipeline; the bottom flue gas lance is arranged at the bottom of the furnace; the main combustion zone flue gas lance is arranged in the main combustion zone; the reduction zone flue gas lance is arranged in the reduction zone; the bottom of the screen flue gas lance is arranged upstream of the staged heat exchange component; the flue gas circulation pipeline leads out circulating flue gas from downstream of the staged heat exchange component and introduces the circulating flue gas into the boiler furnace.

[0005] CN117553314A discloses a boiler operation control method for preventing coking in coal-fired boilers, which is applicable to front and rear wall opposed firing boilers blending high-alkali coal; the method includes: comprehensive anti-coking control from four aspects of air distribution optimization, pulverized coal preparation optimization, soot blowing optimization, and active coke removal; air distribution optimization includes operating oxygen content regulation, primary air velocity regulation, secondary air regulation, and overfire air regulation; pulverized coal preparation optimization includes formulating an economic coal blending plan and controlling the fineness of pulverized coal; soot blowing optimization includes controlling the soot blowing sequence, soot blowing pressure, and soot blowing frequency; active coke removal includes: making coke lumps fall off from the adhesion surface by means of load fluctuation, operating oxygen content fluctuation, furnace negative pressure fluctuation, or soot blowing pressure fluctuation.

[0006] CN116025891A discloses a air distribution control method for suppressing slagging in a tangentially fired boiler burning high-alkali coal, which includes controlling the opening degrees of the secondary air dampers, overfire air dampers, and perimeter air dampers based on the control principles that meet the following conditions I to III: Condition I, the differential pressure between the secondary air plenum and the boiler furnace is 0.4 KPa to 0.95 KPa, and the operating oxygen content is 3.0% to 6.5%; the proportion of secondary air is 60% to 70%, the proportion of overfire air is 25% to 35%, and the proportion of perimeter air is 4% to 5%; Condition II, the opening degrees of the multi-layer secondary air dampers arranged successively from bottom to top along the boiler furnace form a two-stage double-waist air distribution method; Condition III, the opening degrees of the multi-layer overfire air dampers arranged at the top of the boiler furnace are distributed in an equilateral triangle.

[0007] However, the oxygen content measurement points of the above boiler unit are arranged at the outlet of the economizer, and the flue gas temperature measurement points are arranged at the outlet of the horizontal flue. It takes a certain amount of time from the main burner area to the outlet of the economizer. Using the oxygen content at the outlet of the economizer and the flue gas temperature at the outlet of the horizontal flue to adjust the combustion in the main burner area has a certain lag and delay, and it is impossible to achieve precise air distribution and combustion control. Summary of the Invention

[0008] In view of the problems existing in the prior art, the present invention provides a high-alkali coal combustion control device system and method based on dual regulation of oxygen content and flue gas temperature. By setting an oxygen content test module and a flue gas temperature test module at specific positions inside the furnace, and dynamically adjusting the opening degree of the secondary air damper during the combustion of high-alkali coal according to the changes in the oxygen content and flue gas temperature throughout the combustion process, the air distribution control strategy is adjusted, realizing long-term safe and stable combustion of high-alkali coal and reducing the risk of heating surface slagging.

[0009] To achieve this purpose, the present invention adopts the following technical solutions:

[0010] In the first aspect, the present invention provides a high-alkali coal combustion control device system based on dual regulation of oxygen content and flue gas temperature. The high-alkali coal combustion control device system includes an oxygen content test module, a flue gas temperature test module, and a main burner secondary air damper;

[0011] The oxygen content test module is arranged in the burner area and at the outlet of the economizer inside the furnace; the oxygen content test module in the burner area is at the same height as the burner;

[0012] The flue gas temperature test module is arranged in the SOFA air burner area;

[0013] Both the oxygen content test module and the flue gas temperature test module are connected to the main burner secondary air damper.

[0014] The high-alkali coal combustion control device system based on dual regulation of oxygen content and flue gas temperature according to the present invention includes an oxygen content test module arranged in the burner area inside the furnace and at the economizer outlet, and a flue gas temperature test module arranged in the SOFA air burner area, monitoring the oxygen content and flue gas temperature throughout the process, and then regulating the opening degree of the secondary air damper of the main burner to obtain a better air distribution control strategy for high-alkali coal combustion, realizing long-term safe and stable combustion of high-alkali coal by the unit, reducing the risk of fouling on the heating surface, and being suitable for wide promotion and application.

[0015] Preferably, the burner area includes a SOFA air burner area and a pulverized coal burner area.

[0016] The SOFA air burner described in the present invention is a professional name in the field, referring to a separated over-fire air system arranged above the main combustion area of the furnace, introducing hot air separately in the upper part of the furnace through a staged air supply method to further burn out the fuel in the later stage, thereby reducing the generation of NOx.

[0017] The present invention does not specifically limit the test method of the oxygen content test module, and the existing oxygen content test methods in the field can be adopted.

[0018] The present invention does not specifically limit the test method of the flue gas temperature test module, and existing acoustic wave temperature measurement, infrared temperature measurement or high-temperature thermocouple temperature measurement can be adopted.

[0019] Preferably, in a tangentially fired boiler, the oxygen content test module is arranged on the four water-cooled walls in the burner area.

[0020] Preferably, in a tangentially fired boiler, the oxygen content test module includes 4×(n + 1) oxygen content test devices, where n is the number of layers of pulverized coal burners.

[0021] Preferably, in a tangentially fired boiler, the tangent circle rotates counterclockwise, and the calculation formula for the setting distance of the oxygen content test devices on the four water-cooled walls in the A-layer burner area is:

[0022]

[0023] Among them, A1 is the oxygen content test device arranged on the front wall; A2 is the oxygen content test device arranged on the right wall; A3 is the oxygen content test device arranged on the rear wall; A4 is the oxygen content test device arranged on the left wall; NO.1 is the corner of the front wall and the left wall; NO.2 is the corner of the front wall and the left wall; NO.3 is the corner of the rear wall and the left wall; NO.4 is the corner of the front wall and the left wall; L A1-NO.1 represents the length between the oxygen content test device arranged on the front wall and the NO.1 corner; L A2-NO.4 represents the length between the oxygen content test device arranged on the right wall and the NO.4 corner; L A3-NO.3 represents the length between the oxygen content test device arranged on the rear wall and the NO.3 corner; LA4-NO.2 Represents the length between the oxygen content testing device arranged on the left wall and the NO.2 corner; L 前墙 Represents the length of the front wall; L 右墙 Represents the length of the right wall; L 后墙 Represents the length of the rear wall; L 左墙 Represents the length of the left wall; r 切圆 Represents the radius of the tangential circle; α represents the burner tangential angle.

[0024] Preferably, in a boiler with opposed firing on the front and rear walls, the oxygen content testing module is arranged on the left wall and the right wall.

[0025] Preferably, in a boiler with opposed firing on the front and rear walls, the oxygen content testing module includes 2×(n + 2) oxygen content testing devices, where n is the number of pulverized coal burner layers.

[0026] Preferably, in a boiler with opposed firing on the front and rear walls, the installation distance of the oxygen content testing devices is 0.4 - 0.5 times the length of the corresponding side wall. For example, it can be 0.4 times, 0.42 times, 0.44 times, 0.45 times, 0.47 times, 0.49 times, or 0.5 times, etc., but is not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0027] In the present invention, the positions of the oxygen content testing devices arranged on different numbers of burner layers can be different.

[0028] Preferably, the flue gas temperature testing module includes 2 - 4 flue gas temperature testing devices. For example, it can be 2, 3, or 4.

[0029] The flue gas temperature testing module of the present invention is arranged in the SOFA air burner area, and 2 - 4 flue gas temperature testing devices are symmetrically arranged on the left and right walls.

[0030] The present invention provides corresponding setting methods for the oxygen content testing module according to two existing different furnace types, realizing the whole - process monitoring of the oxygen content and facilitating more precise regulation of the opening degree of the secondary air dampers.

[0031] In a second aspect, the present invention also provides a high - alkali coal combustion control method based on dual regulation of oxygen content and flue gas temperature. The high - alkali coal combustion control method is carried out by using the high - alkali coal combustion control device system described in the first aspect;

[0032] When the unit operating load > 75% of the rated load, start the high - alkali coal combustion control device system described above for correcting the opening degree of the secondary air dampers.

[0033] When the operating load of the unit > 75% of the rated load, for example, it can be 75.5% of the rated load, 76% of the rated load, 78% of the rated load, 80% of the rated load, 85% of the rated load, 88% of the rated load, or 90% of the rated load, etc., but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0034] Preferably, the high-alkali coal combustion control method includes:

[0035] When the average oxygen content measured by the oxygen content measuring device at each layer of burners in the burner zone is < 2%, for example, it can be 1.9%, 1.8%, 1.5%, 1.3%, 1.1%, or 1%, etc., but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable. The correction percentage of the secondary air damper opening corresponding to this layer of burners is 15% - 20%, for example, it can be 15%, 16%, 18%, 18.3%, 18.5%, 19%, 19.5%, 19.8%, or 20%, etc., but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0036] When the average oxygen content measured by the oxygen content measuring device at each layer of burners in the burner zone is 2 - 2.5%, for example, it can be 2%, 2.1%, 2.2%, 2.3%, 2.4%, or 2.5%, etc., but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable. The correction percentage of the secondary air damper opening corresponding to this layer of burners is 10% - 15%, for example, it can be 10%, 12%, 13%, 13.5%, 14%, 14.5%, 14.8%, 14.9%, or 15%, etc., but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0037] When the average oxygen content measured by the oxygen content measuring device at each layer of burners in the burner zone is 2.5 - 3%, for example, it can be 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, or 3%, etc., but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable. The correction percentage of the secondary air damper opening corresponding to this layer of burners is 5% - 10%, for example, it can be 5%, 6%, 7%, 7.5%, 8%, 9%, or 10%, etc., but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0038] When the average oxygen content measured by the oxygen content testing device at each layer of burners in the burner area is 3.5% - 4%, for example, it can be 3.5%, 3.55%, 3.6%, 3.65%, 3.7%, 3.8% or 4%, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable. The correction percentage of the secondary air damper opening corresponding to this layer of burners is 0.

[0039] When the average flue gas temperature measured by the flue gas temperature testing module is 1100 - 1150 °C, for example, it can be 1100 °C, 1105 °C, 1110 °C, 1120 °C, 1130 °C, 1140 °C or 1150 °C, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable. The correction percentage of the opening of all secondary air dampers is 0.

[0040] When the average flue gas temperature measured by the flue gas temperature testing module is 1200 °C, the correction percentage of the opening of all secondary air dampers is 1% - 7%, for example, it can be 1%, 2%, 3%, 4%, 5%, 6% or 7%, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0041] When the average flue gas temperature measured by the flue gas temperature testing module is 1250 °C, the correction percentage of the opening of all secondary air dampers is 8% - 10%, for example, it can be 8%, 8.5%, 8.8%, 9%, 9.3%, 9.5% or 10%, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0042] When the average flue gas temperature measured by the flue gas temperature testing module is 1300 °C, the correction percentage of the opening of all secondary air dampers is 18% - 25%, for example, it can be 18%, 18.5%, 18.8%, 19%, 19.3%, 19.5%, 20%, 23% or 25%, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable.

[0043] The high-alkali coal combustion control method based on dual regulation of oxygen content and flue gas temperature described in the present invention takes into account that high-alkali coal is prone to coking mainly under high load, and the coking risk is low under medium and low load. The two-dimensional regulation of oxygen content and flue gas temperature increases the load limit. When the load is lower than 75% of the rated load, the oxygen content and flue gas temperature do not participate in the regulation; when the unit operating load > 75% of the rated load, the high-alkali coal combustion control device system based on dual regulation of oxygen content and flue gas temperature is started to correct the opening of the secondary air dampers. The present invention realizes the fine control of the whole process of combustion through the data measured by the oxygen content testing module and the flue gas temperature testing module set at specific positions, and can greatly reduce the coking risk of the heating surface.

[0044] In the present invention, the opening degree of the secondary air damper corresponding to each layer of burners is adjusted according to the average oxygen content measured by the oxygen content measuring device at each layer of burners; the opening degree of all secondary air dampers is adjusted according to the average flue gas temperature measured by the flue gas temperature measuring module.

[0045] Preferably, the opening degree of the secondary air damper corresponding to each layer of burners is the sum of the correction percentage of the opening degree of the secondary air damper corresponding to the average oxygen content at this layer of burners, the correction percentage of the opening degree of all secondary air dampers corresponding to the average flue gas temperature, and the original opening degree percentage of this layer of secondary air dampers.

[0046] As a preferred technical solution of the present invention, the high-alkali coal combustion control method includes:

[0047] When the unit operating load > 75% of the rated load, the high-alkali coal combustion control device system based on dual regulation of oxygen content and flue gas temperature is started to correct the opening degree of the secondary air damper;

[0048] When the average oxygen content measured by the oxygen content measuring device at each layer of burners in the burner area < 2%, the correction percentage of the opening degree of the secondary air damper corresponding to this layer of burners is 15% - 20%;

[0049] When the average oxygen content measured by the oxygen content measuring device at each layer of burners in the burner area is 2 - 2.5%, the correction percentage of the opening degree of the secondary air damper corresponding to this layer of burners is 10% - 15%;

[0050] When the average oxygen content measured by the oxygen content measuring device at each layer of burners in the burner area is 2.5 - 3%, the correction percentage of the opening degree of the secondary air damper corresponding to this layer of burners is 5% - 10%;

[0051] When the average oxygen content measured by the oxygen content measuring device at each layer of burners in the burner area is 3.5% - 4%, the correction percentage of the opening degree of the secondary air damper corresponding to this layer of burners is 0;

[0052] When the average flue gas temperature measured by the flue gas temperature measuring module is 1100 - 1150 °C, the correction percentage of the opening degree of all secondary air dampers is 0;

[0053] When the average flue gas temperature measured by the flue gas temperature measuring module is 1200 °C, the correction percentage of the opening degree of all secondary air dampers is 1% - 7%;

[0054] When the average flue gas temperature measured by the flue gas temperature measuring module is 1250 °C, the correction percentage of the opening degree of all secondary air dampers is 8% - 10%;

[0055] When the average flue gas temperature measured by the flue gas temperature measuring module is 1300 °C, the correction percentage of the opening degree of all secondary air dampers is 18% - 25%;

[0056] The opening degree of the secondary air damper corresponding to each layer of burners is the sum of the correction percentage of the opening degree of the secondary air damper corresponding to the average oxygen content at the location of this layer of burners, the correction percentage of the opening degree of all secondary air dampers corresponding to the average flue gas temperature, and the original opening degree percentage of this layer of secondary air dampers.

[0057] Compared with the prior art, the present invention has at least the following beneficial effects:

[0058] The present invention provides a high-alkali coal combustion control device system and method based on dual regulation of oxygen content and flue gas temperature. Through the two-dimensional and whole-process refined adjustment of the oxygen content and flue gas temperature in the co-firing of high-alkali coal in coal-fired power generation, the opening degree of the secondary air damper is optimized, a better air distribution strategy is provided, the oxygen content in the main combustion area is increased, the residence time of coal powder particles in the furnace is increased, the flame center is lowered, the burnout characteristics of coal powder are strengthened, the fouling of the heating surface is inhibited, the co-firing ratio of high-alkali coal is increased, and obvious economic benefits can be brought. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a schematic installation diagram of the oxygen content test module in the tangentially fired boiler in the specific embodiment of the present invention.

[0060] Figure 2 It is a schematic installation diagram of the oxygen content test module in the front and rear wall opposed firing boiler in the specific embodiment of the present invention.

[0061] Figure 3 Taking layer A in the coal powder burner area as an example, it is a schematic installation diagram of the oxygen content test device in the tangentially fired boiler in the specific embodiment of the present invention.

[0062] Figure 4 Taking layer A and layer C in the coal powder burner area as examples, it is a schematic installation diagram of the oxygen content test device in the front and rear wall opposed firing boiler in the specific embodiment of the present invention.

[0063] Figure 5 It is a schematic installation diagram of the flue gas temperature test module in the specific embodiment of the present invention.

[0064] In the figure: 1 - coal powder burner area; 2 - SOFA air burner area; 3 - oxygen content test module installed at the coal powder burner area; 4 - oxygen content test module installed at the SOFA air burner area; 5 - oxygen content test module installed at the economizer outlet; 6 - flue gas temperature test module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0065] The technical solution of the present invention will be further described below in conjunction with the drawings and through specific embodiments.

[0066] The present invention will be described in further detail below. However, the following examples are only simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0067] It should be understood that in the description of the present invention, the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0068] It should be noted that in the description of the present invention, unless otherwise clearly specified and defined, the terms "set", "connected", "connected to" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0069] As a specific embodiment of the present invention, a high-alkali coal combustion control device system based on dual regulation of oxygen content and flue gas temperature is provided. The high-alkali coal combustion control device system includes an oxygen content test module, a flue gas temperature test module 6, and the secondary air dampers of the main burner;

[0070] The oxygen content test module is arranged in the burner area inside the furnace and at the outlet of the economizer; the oxygen content test module in the burner area is arranged at the same height as the burner;

[0071] The flue gas temperature test module 6 is arranged in the SOFA air burner area 2;

[0072] Both the oxygen content test module and the flue gas temperature test module 6 are connected to the secondary air dampers of the main burner.

[0073] The burner area includes the SOFA air burner area 2 and the pulverized coal burner area 1.

[0074] The installation schematic diagram of the oxygen content test module in a tangentially fired boiler is as Figure 1 shown, and the installation schematic diagram of the oxygen content test module in a front-back wall opposed fired boiler is as Figure 2 shown, Figure 1 andFigure 2 Among them, 3 is the oxygen content testing module installed at the pulverized coal burner area 1; 4 is the oxygen content testing module installed at the SOFA air burner area 2; 5 is the oxygen content testing module installed at the economizer outlet.

[0075] In a tangentially fired boiler with corners, the oxygen content testing module is arranged on the four water-cooled walls in the burner area;

[0076] In a tangentially fired boiler with corners, the oxygen content testing module includes 4×(n + 1) oxygen content testing devices, where n is the number of layers of pulverized coal burners.

[0077] In this specific embodiment, when n = 6, the oxygen content testing module includes 4×(6 + 1) = 28 oxygen content testing devices.

[0078] Taking the A layer in the pulverized coal burner area 1 as an example, the installation schematic diagram of the oxygen content testing devices in a tangentially fired boiler with corners is as Figure 3 shown. The oxygen content testing devices are respectively named A1, A2, A3, and A4, and the corners of adjacent water-cooled wall surfaces are respectively named NO.1, NO.2, NO.3, and NO.4.

[0079] In a tangentially fired boiler with corners, the tangent circle rotates counterclockwise, and the calculation formula for the setting distance of the oxygen content testing devices on the four water-cooled walls in the A layer burner area is:

[0080]

[0081] Among them, A1 is the oxygen content testing device arranged on the front wall; A2 is the oxygen content testing device arranged on the right wall; A3 is the oxygen content testing device arranged on the rear wall; A4 is the oxygen content testing device arranged on the left wall; NO.1 is the corner of the front wall and the left wall; NO.2 is the corner of the front wall and the left wall; NO.3 is the corner of the rear wall and the left wall; NO.4 is the corner of the front wall and the left wall; L A1-NO.1 represents the length between the oxygen content testing device arranged on the front wall and the NO.1 corner; L A2-NO.4 represents the length between the oxygen content testing device arranged on the right wall and the NO.4 corner; L A3-NO.3 represents the length between the oxygen content testing device arranged on the rear wall and the NO.3 corner; L A4-NO.2 represents the length between the oxygen content testing device arranged on the left wall and the NO.2 corner; L 前墙 represents the length of the front wall; L 右墙 represents the length of the right wall; L 后墙 represents the length of the rear wall; L 左墙 represents the length of the left wall; r 切圆 represents the radius of the tangent circle; α represents the burner cutting angle.

[0082] In a boiler with opposed firing on the front and rear walls, the oxygen content testing module is arranged on the left wall and the right wall;

[0083] In a front-back wall opposed firing boiler, the oxygen content measurement module includes 2×(n + 2) oxygen content measurement devices, where n is the number of layers of pulverized coal burners.

[0084] In this specific embodiment, when n = 3, the oxygen content measurement module includes 2×(3 + 2) = 10 oxygen content measurement devices.

[0085] Taking the A layer and the C layer in the pulverized coal burner area 1 as an example, the installation schematic diagram of the oxygen content measurement devices in the front-back wall opposed firing boiler is as Figure 4 shown, and the oxygen content measurement devices are respectively named A1, A2, C1, and C2.

[0086] In the front-back wall opposed firing boiler, the set distance of the oxygen content measurement devices is 0.455 times the length of the corresponding side wall, that is

[0087] L A1 = 右墙 ×0.455

[0088] L A2 =L 左墙 ×0.455

[0089] L 右墙 represents the length of the right wall of the front-back wall opposed firing boiler, and L 左墙 represents the length of the left wall of the front-back wall opposed firing boiler.

[0090] The installation schematic diagram of the flue gas temperature measurement module in this specific embodiment is as Figure 5 shown, Figure 5 where 6 is the flue gas temperature measurement module.

[0091] The flue gas temperature measurement module 6 includes 2 flue gas temperature measurement devices.

[0092] As a specific embodiment of the present invention, a high-alkali coal combustion control method based on dual regulation of oxygen content and flue gas temperature is also provided. The high-alkali coal combustion control method is carried out by using the above-mentioned high-alkali coal combustion control device system based on dual regulation of oxygen content and flue gas temperature; the high-alkali coal combustion control method includes:

[0093] When the unit operating load is 78% of the rated load, start the above-mentioned high-alkali coal combustion control device system based on dual regulation of oxygen content and flue gas temperature to correct the opening of the secondary air damper.

[0094] In this specific embodiment, the burner area of the tangentially fired boiler at the four corners includes the SOFA air burner area 2 and the pulverized coal burner area 1. Among them, the number of layers of the pulverized coal burners is 6, which are named layer A, layer B, layer C, layer D, layer E, and layer F from bottom to top. Then, the average oxygen content measured by the oxygen content measuring device at the SOFA air burner is 3.7%, and the correction percentage of the opening of the secondary air damper in the SOFA air area is 0; the average flue gas temperature measured by the flue gas temperature measuring module is 1250°C, and the correction percentage of the opening of all secondary air dampers is 10%. Add the above correction percentages of the opening of the secondary air damper: 0 + 10% = 10%. Add this added percentage of 10% to the original percentage of the opening of the secondary air damper in the SOFA air area, which is 30%, to obtain the final percentage of the opening of the secondary air damper in the SOFA air area, which is 40%.

[0095] The average oxygen content measured by the oxygen content measuring device at layer A of the pulverized coal burner is 2.2%, and the correction percentage of the opening of the secondary air damper corresponding to layer A of the pulverized coal burner is 15%; the average flue gas temperature measured by the flue gas temperature measuring module is 1250°C, and the correction percentage of the opening of all secondary air dampers is 10%. Add the above correction percentages of the opening of the secondary air damper: 15% + 10% = 25%. Add this added percentage of 25% to the original percentage of the opening of the secondary air damper of this layer, which is 25%, to obtain the final percentage of the opening of the secondary air damper, which is 50%.

[0096] The average oxygen content measured by the oxygen content measuring device at layer B of the pulverized coal burner is 2.7%, and the correction percentage of the opening of the secondary air damper corresponding to layer B of the pulverized coal burner is 10%; the average flue gas temperature measured by the flue gas temperature measuring module is 1250°C, and the correction percentage of the opening of all secondary air dampers is 10%. Add the above correction percentages of the opening of the secondary air damper: 10% + 10% = 20%. Add this added percentage of 20% to the original percentage of the opening of the secondary air damper of this layer, which is 20%, to obtain the final percentage of the opening of the secondary air damper, which is 40%.

[0097] The average oxygen content measured by the oxygen content measuring device at layer C of the pulverized coal burner is 3%, and the correction percentage of the opening of the secondary air damper corresponding to layer C of the pulverized coal burner is 10%; the average flue gas temperature measured by the flue gas temperature measuring module is 1250°C, and the correction percentage of the opening of all secondary air dampers is 10%. Add the above correction percentages of the opening of the secondary air damper: 10% + 10% = 20%. Add this added percentage of 20% to the original percentage of the opening of the secondary air damper of this layer, which is 20%, to obtain the final percentage of the opening of the secondary air damper, which is 40%.

[0098] The average oxygen content measured by the oxygen content testing device at the D-layer of the pulverized coal burner is 3.6%, and the correction percentage of the opening of the secondary air damper corresponding to the D-layer of the pulverized coal burner is 0; the average flue gas temperature measured in the flue gas temperature testing module is 1250 °C, and the correction percentage of the opening of all secondary air dampers is 10%. The above correction percentages of the opening of the secondary air damper are added up: 0 + 10% = 10%. This added percentage of 10% is added to the original percentage of the opening of the secondary air damper of this layer, which is 10%, to obtain the final percentage of the opening of the secondary air damper, which is 20%.

[0099] The average oxygen content measured by the oxygen content testing device at the E-layer of the pulverized coal burner is 3.7%, and the correction percentage of the opening of the secondary air damper corresponding to the E-layer of the pulverized coal burner is 0; the average flue gas temperature measured in the flue gas temperature testing module is 1250 °C, and the correction percentage of the opening of all secondary air dampers is 10%. The above correction percentages of the opening of the secondary air damper are added up: 0 + 10% = 10%. This added percentage of 10% is added to the original percentage of the opening of the secondary air damper of this layer, which is 10%, to obtain the final percentage of the opening of the secondary air damper, which is 20%.

[0100] The average oxygen content measured by the oxygen content testing device at the F-layer of the pulverized coal burner is 4%, and the correction percentage of the opening of the secondary air damper corresponding to the F-layer of the pulverized coal burner is 0; the average flue gas temperature measured in the flue gas temperature testing module is 1250 °C, and the correction percentage of the opening of all secondary air dampers is 10%. The above correction percentages of the opening of the secondary air damper are added up: 0 + 10% = 10%. This added percentage of 10% is added to the original percentage of the opening of the secondary air damper of this layer, which is 10%, to obtain the final percentage of the opening of the secondary air damper, which is 20%.

[0101] In this specific embodiment, the burner area of the front and rear wall opposed firing boiler includes the SOFA air burner area 2 and the pulverized coal burner area 1. Among them, the number of layers of the pulverized coal burner is 3, which are named A-layer, B-layer and C-layer from bottom to top. Then, the average oxygen content measured by the oxygen content testing device at the SOFA air burner is 3.7%, and the correction percentage of the opening of the secondary air damper in the SOFA air area is 0; the average flue gas temperature measured in the flue gas temperature testing module is 1250 °C, and the correction percentage of the opening of all secondary air dampers is 10%. The above correction percentages of the opening of the secondary air damper are added up: 0 + 10% = 10%. This added percentage of 10% is added to the original percentage of the opening of the secondary air damper in the SOFA air area of this layer, which is 30%, to obtain the final percentage of the opening of the secondary air damper in the SOFA air area, which is 40%.

[0102] The average oxygen content measured by the oxygen content testing device at the A-layer area of the burner is 1.2%, and the correction percentage of the secondary air damper opening corresponding to the A-layer area of the burner is 20%; the average flue gas temperature measured by the flue gas temperature testing module is 1250 °C, and the correction percentage of the opening of all secondary air dampers is 10%. Add the above correction percentages of the secondary air damper opening at the A-layer area of the burner: 20% + 10% = 30%. Add this added percentage of 30% to the original percentage of the secondary air damper opening at the A-layer area of the burner, which is 30%, to obtain the final percentage of the secondary air damper opening at the A-layer area of the burner as 60%.

[0103] The average oxygen content measured by the oxygen content testing device at the B-layer of the pulverized coal burner is 2.7%, and the correction percentage of the secondary air damper opening corresponding to the B-layer of the pulverized coal burner is 10%; the average flue gas temperature measured by the flue gas temperature testing module is 1250 °C, and the correction percentage of the opening of all secondary air dampers is 10%. Add the above correction percentages of the secondary air damper opening: 10% + 10% = 20%. Add this added percentage of 20% to the original percentage of the secondary air damper opening at this layer, which is 20%, to obtain the final percentage of the secondary air damper opening as 40%.

[0104] The average oxygen content measured by the oxygen content testing device at the C-layer of the pulverized coal burner is 3%, and the correction percentage of the secondary air damper opening corresponding to the C-layer of the pulverized coal burner is 10%; the average flue gas temperature measured by the flue gas temperature testing module is 1250 °C, and the correction percentage of the opening of all secondary air dampers is 10%. Add the above correction percentages of the secondary air damper opening: 10% + 10% = 20%. Add this added percentage of 20% to the original percentage of the secondary air damper opening at this layer, which is 20%, to obtain the final percentage of the secondary air damper opening as 40%.

[0105] In summary, the high-alkali coal combustion control device system and method based on dual regulation of oxygen content and flue gas temperature provided by the present invention optimize the opening of the secondary air damper by reasonably setting the positions of the oxygen content testing module and the flue gas temperature testing module, and conduct full-process fine adjustment of the oxygen content and flue gas temperature in the co-firing of high-alkali coal in coal-fired power generation, providing a better strategy for air distribution, increasing the oxygen content in the main combustion area, increasing the residence time of pulverized coal particles in the furnace, lowering the flame center, strengthening the burnout characteristics of pulverized coal, inhibiting the coking of the heating surface, increasing the co-firing ratio of high-alkali coal, and bringing obvious economic benefits, having broad prospects for large-scale popularization and application.

[0106] The applicant declares that the above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A combustion control device system for high-alkali coal based on dual regulation of oxygen content and flue gas temperature, characterized in that, The high-alkali coal combustion control device system includes an oxygen content testing module, a flue gas temperature testing module, and the secondary air dampers of the main burners; The oxygen content testing module is arranged in the burner area inside the furnace and at the outlet of the economizer; the oxygen content testing module in the burner area is set at the same height as the burner; The flue gas temperature testing module is arranged in the SOFA air burner area; Both the oxygen content testing module and the flue gas temperature testing module are connected to the secondary air dampers of the main burners.

2. The high-alkali coal combustion control device system according to claim 1, wherein The burner area includes the SOFA air burner area and the pulverized coal burner area.

3. The high-alkali coal combustion control device system according to claim 1 or 2, characterized in that In a tangentially fired boiler, the oxygen content testing module is arranged on the four water-cooled walls in the burner area; Preferably, in a tangentially fired boiler, the oxygen content testing module includes 4×(n + 1) oxygen content testing devices, where n is the number of layers of pulverized coal burners.

4. The high-alkali coal combustion control device system according to any one of claims 1 to 3, characterized in that In a tangentially fired boiler, the tangential circle rotates counterclockwise, and the calculation formula for the installation distance of the oxygen content testing devices on the four water-cooled walls in the A-layer burner area is: Among them, A1 is the oxygen content testing device arranged on the front wall; A2 is the oxygen content testing device arranged on the right wall; A3 is the oxygen content testing device arranged on the rear wall; A4 is the oxygen content testing device arranged on the left wall; NO.1 is the corner between the front wall and the left wall; NO.2 is the corner between the front wall and the left wall; NO.3 is the corner between the rear wall and the left wall; NO.4 is the corner between the front wall and the left wall; L A1-NO.1 represents the length between the oxygen content testing device arranged on the front wall and the NO.1 corner; L A2-NO.4 represents the length between the oxygen content testing device arranged on the right wall and the NO.4 corner; L A3-NO.3 represents the length between the oxygen content testing device arranged on the rear wall and the NO.3 corner; L A4-NO.2 represents the length between the oxygen content testing device arranged on the left wall and the NO.2 corner; L 前墙 represents the length of the front wall; L 右墙 represents the length of the right wall; L 后墙 represents the length of the rear wall; L 左墙 represents the length of the left wall; r 切圆 represents the radius of the tangential circle; α represents the burner tangential angle.

5. The high-alkali coal combustion control device system according to any one of claims 1 to 4, characterized in that In a boiler with opposed firing from the front and rear walls, the oxygen content testing module is arranged on the left wall and the right wall; Preferably, in a boiler with opposed firing from the front and rear walls, the oxygen content testing module includes 2×(n + 2) oxygen content testing devices, where n is the number of layers of pulverized coal burners.

6. The high-alkali coal combustion control device system according to any one of claims 1 to 5, characterized in that, In a boiler with opposed firing from the front and rear walls, the installation distance of the oxygen content testing devices is 0.35 - 0.45 times the length of the corresponding side wall.

7. The high-alkali coal combustion control device system according to any one of claims 1 to 6, characterized in that, The flue gas temperature testing module includes 2 - 4 flue gas temperature testing devices.

8. A combustion control method for high-alkali coal based on dual regulation of oxygen content and flue gas temperature, characterized in that, The high-alkali coal combustion control method is carried out by using the high-alkali coal combustion control device system based on dual regulation of oxygen content and flue gas temperature described in any one of claims 1 - 7; the high-alkali coal combustion control method includes: When the unit operating load > 75% of the rated load, start the high-alkali coal combustion control device system based on dual regulation of oxygen content and flue gas temperature to correct the opening degree of the secondary air dampers.

9. The high-alkali coal combustion control method according to claim 8, wherein The high-alkali coal combustion control method includes: When the average oxygen content measured by the oxygen content testing devices at each layer of burners in the burner area is < 2%, the correction percentage of the opening degree of the secondary air dampers corresponding to this layer of burners is 15% - 20%; When the average oxygen content measured by the oxygen content testing devices at each layer of burners in the burner area is 2 - 2.5%, the correction percentage of the opening degree of the secondary air dampers corresponding to this layer of burners is 10% - 15%; When the average oxygen content measured by the oxygen content testing devices at each layer of burners in the burner area is 2.5 - 3%, the correction percentage of the opening degree of the secondary air dampers corresponding to this layer of burners is 5% - 10%; When the average oxygen content measured by the oxygen content testing devices at each layer of burners in the burner area is 3.5% - 4%, the correction percentage of the opening degree of the secondary air dampers corresponding to this layer of burners is 0; When the average flue gas temperature measured in the flue gas temperature testing module is 1100 - 1150 °C, the correction percentage of the opening degree of all secondary air dampers is 0; When the average flue gas temperature measured in the flue gas temperature testing module is 1200 °C, the correction percentage of the opening degree of all secondary air dampers is 1% - 7%; When the average flue gas temperature measured in the flue gas temperature testing module is 1250 °C, the correction percentage of the opening degree of all secondary air dampers is 8% - 10%; When the average flue gas temperature measured by the flue gas temperature test module is 1300 °C, the correction percentage of the opening degree of all secondary air dampers is 18% - 25%.

10. The high-alkali coal combustion control method according to claim 8 or 9, characterized in that, The opening degree of the secondary air damper corresponding to each layer of burners is the sum of the correction percentage of the opening degree of the secondary air damper corresponding to the average oxygen content at the location of this layer of burners, the correction percentage of the opening degree of all secondary air dampers corresponding to the average flue gas temperature, and the original opening degree percentage of the secondary air damper of this layer.

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