A method for judging a low-sodium coal blending combustion position of a front and back wall opposed boiler
By evaluating the low-sodium coal co-firing location of the front and rear wall opposed boiler and using a three-level judgment surface to determine the burner fullness, the problem of easy slagging during high-sodium coal combustion was solved, and the effective utilization of low-sodium coal and the extension of equipment life were achieved.
Patent Information
- Application Number
- CN202310082601.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-01-31
- Publication Date
- 2026-02-06
- Estimated Expiration
- 2043-01-31
AI Technical Summary
High-sodium coal is prone to slagging when burned in boilers, which shortens the service life of equipment and limits its utilization rate. In addition, low-sodium coal has small reserves and high prices, and existing technologies lack effective methods for evaluating the location of low-sodium coal blending.
The furnace filling degree of the mixed airflow at the primary air nozzle of the single-layer burner is determined by the three-level auxiliary judgment surface. The average filling degree ratio of the burners operating on the front and rear walls and the furnace mixing index are calculated to determine the co-firing location of low-sodium coal.
By making reasonable use of low-sodium coal, the problem of slagging during the combustion of high-sodium coal has been solved, the service life of boiler equipment has been extended, and the effective utilization of low-sodium coal has been achieved.
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Figure CN116085784B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of coal-fired power generation technology, and particularly relates to a method for judging a low-sodium coal blending combustion position of a front-back wall opposed boiler. BACKGROUND
[0002] Most front-back wall opposed boilers adopt cyclone burners, the burners are arranged opposite to each other on the front and back walls of the furnace body, and the pulverized coal is carried by the airflow to the furnace to undergo a heating, ignition and burnout process. High-sodium coal has the advantages of large reserves, low mining cost and low content of harmful substances in raw coal, but the content of alkali metal in high-sodium coal is high. When high-sodium coal is burned, the sodium-containing components in the coal ash will condense on the heat exchange surface of the equipment and react with SO2 and SO3 in the flue gas to produce sodium sulfate and other substances to form a dense and cohesive layer. This cohesive layer not only reacts with the metal tube wall to cause high-temperature corrosion, but also can capture coal ash particles in the flue gas to cause high-temperature cohesive deposition, resulting in a significant reduction in the service life of the equipment and causing serious economic losses. The existence of these problems greatly limits the utilization rate of high-sodium coal and directly affects the economic benefits and sustainable development of coal enterprises. The content of alkali metal in low-sodium coal is low, and it is not easy to produce slagging when burned in a boiler. Blending low-sodium coal with high-sodium coal can to some extent solve the problem of slagging when high-sodium coal is burned in a boiler, but the reserves of low-sodium coal are small and the price is high, so it is necessary to make full use of low-sodium coal for blending combustion. Therefore, it is necessary to propose a method for evaluating the blending combustion position of low-sodium coal in a boiler to make full use of low-sodium coal for blending combustion. SUMMARY
[0003] The present application aims to at least partially solve one of the problems in the related art.
[0004] To this end, an embodiment of the present application proposes a method for judging a low-sodium coal blending combustion position of a front-back wall opposed boiler.
[0005] The present application proposes a method for judging a low-sodium coal blending combustion position of a front-back wall opposed boiler, comprising the following steps:
[0006] (1) judging the furnace fullness of the mixed gas stream of the primary air nozzle of the single-layer burner through a three-level auxiliary judgment surface;
[0007] (2) obtaining the average fullness of the front wall operating burner and the average fullness of the back wall operating burner according to the fullness of the single-layer burner;
[0008] (3) judging the furnace mixing index according to the product of the average fullness of the front wall operating burner and the average fullness of the back wall operating burner;
[0009] (4) judging the blending combustion position of the low-sodium coal according to the ratio of the average fullness of the front wall operating burner and the average fullness of the back wall operating burner.
[0010] In some embodiments, the three-level auxiliary judgment surface includes a first-level judgment surface, a second-level judgment surface and a third-level judgment surface, the first-level judgment surface is a middle section of the front and rear walls at the upper level of the overfire air, the second-level judgment surface is a middle section of the narrowest part of the flue gas turning angle channel, and the third-level judgment surface is a middle section in the height direction of the horizontal flue.
[0011] In some embodiments, the single-layer primary air mixed gas flow mainly flows across the first-level judgment surface and across the second-level judgment surface and / or the third-level judgment surface, which is high fullness.
[0012] In some embodiments, the single-layer primary air mixed gas flow mainly flows across the first-level judgment surface and does not flow across the second-level judgment surface and the third-level judgment surface, or the single-layer primary air mixed gas flow does not flow across the first-level judgment surface and flows across the second-level judgment surface and the third-level judgment surface, which is sub-fullness.
[0013] In some embodiments, the single-layer primary air mixed gas flow does not flow across the first-level judgment surface and does not flow across the second-level judgment surface and / or the third-level judgment surface, which is low fullness.
[0014] In some embodiments, the single-layer primary air mixed gas flow mainly flows across the first-level judgment surface and across the second-level judgment surface and / or the third-level judgment surface, which is high fullness.
[0015] In some embodiments, the single-layer primary air mixed gas flow mainly flows across the first-level judgment surface and across the second-level judgment surface and / or the third-level judgment surface, which is high fullness.
[0016] In some embodiments, when the fullness of the single-layer burner is high fullness, low-sodium coal blending is performed; when the fullness of the single-layer burner is low fullness, low-sodium coal blending is not performed.
[0017] In some embodiments, when the ratio of the average fullness of the front wall operating burner to the average fullness of the rear wall operating burner is greater than 1, low-sodium coal is blended in the lower layer of the front wall; when the ratio of the average fullness of the front wall operating burner to the average fullness of the rear wall operating burner is less than 1, low-sodium coal is blended in the lower layer of the rear wall; and when the ratio of the average fullness of the front wall operating burner to the average fullness of the rear wall operating burner is equal to 1, the blending position of the low-sodium coal is determined in combination with the furnace mixing index.
[0018] In some embodiments, the average fullness of the front wall operating burner is the average value of the fullness of all single-layer burners operating in the front wall, and the average fullness of the rear wall operating burner is the average value of the fullness of all single-layer burners operating in the rear wall.
[0019] Compared with the prior art, the present application has the following beneficial effects:
[0020] The application judges the fullness of the mixed gas flow in the furnace through three auxiliary judgment surfaces of single-layer burners, judges the blending position of low-sodium coal according to the mixing ratio of the front and rear walls and the furnace mixing index, can reasonably blend low-sodium coal, fully utilizes low-sodium coal, and solves the problem of high-sodium coal combustion and slagging at a low cost. BRIEF DESCRIPTION OF DRAWINGS
[0021] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the accompanying drawings, wherein:
[0022] Figure 1 It is a schematic diagram of the main flow line of the primary air mixed gas flow of the front wall A layer burner in some embodiments.
[0023] Figure 2 It is a schematic diagram of the main flow line of the primary air mixed gas flow of the rear wall B layer burner in some embodiments. DETAILED DESCRIPTION
[0024] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.
[0025] The evaluation method of the low-sodium coal blending position of the front and rear wall opposed wall boiler according to the embodiments of the present application is described below with reference to the accompanying drawings.
[0026] The evaluation method of the low-sodium coal blending position of the front and rear wall opposed wall boiler of the present application comprises the following steps:
[0027] (1) judging the fullness of the mixed gas flow in the furnace through three auxiliary judgment surfaces of single-layer burners;
[0028] (2) obtaining the average fullness of the front wall operating burners and the average fullness of the rear wall operating burners according to the fullness of the single-layer burners;
[0029] (3) judging the furnace mixing index according to the product of the average fullness of the front wall operating burners and the average fullness of the rear wall operating burners;
[0030] (4) judging the blending position of low-sodium coal according to the ratio of the average fullness of the front wall operating burners and the average fullness of the rear wall operating burners.
[0031] The present application judges whether a layer of burners is conducive to blending low-sodium coal according to the fullness of the mixed gas flow in the furnace through the primary air nozzle of the single-layer burners.
[0032] When the fullness of the single-layer burner is high fullness, low-sodium coal blending is carried out; when the fullness of the single-layer burner is low fullness, low-sodium coal blending is not carried out. Specifically, when the fullness of the single-layer burner primary air nozzle mixed gas flow in the furnace is high fullness, it is beneficial to the blending of low-sodium coal; when the fullness of the single-layer burner primary air nozzle mixed gas flow in the furnace is sub-fullness, it is not recommended to blend low-sodium coal; when the fullness of the single-layer burner primary air nozzle mixed gas flow in the furnace is low fullness, low-sodium coal blending cannot be carried out.
[0033] The auxiliary judgment surface of the third level includes the first level judgment surface, the second level judgment surface and the third level judgment surface, the first level judgment surface is the middle section of the front and rear walls at the height of the upper overfire air, the second level judgment surface is the middle section of the narrowest part of the arched flue, and the third level judgment surface is the middle section in the height direction of the horizontal flue.
[0034] The positions of the first level judgment surface, the second level judgment surface and the third level judgment surface in the front and rear wall opposed boiler are shown in Figure 1 and Figure 2 , wherein the positions of Q and H are the positions of the upper overfire air height.
[0035] The single-layer primary air mixed gas flow is mainly in the streamline across the first level judgment surface and across the second level judgment surface and / or the third level judgment surface, which is high fullness.
[0036] Specifically, when the fullness of the single-layer burner primary air nozzle mixed gas flow in the furnace is high fullness, it is divided into the following three cases. The first case is that the single-layer primary air mixed gas flow is mainly in the streamline across the first level judgment surface, the second level judgment surface and the third level judgment surface; the second case is that the single-layer primary air mixed gas flow is mainly in the streamline across the first level judgment surface and the second level judgment surface, and does not cross the third level judgment surface; the third case is that the single-layer primary air mixed gas flow is mainly in the streamline across the first level judgment surface and the third level judgment surface, and does not cross the second level judgment surface.
[0037] In some embodiments, the schematic diagram of the primary air mixed gas flow of the back wall B layer burner is shown in Figure 2 At this time, the primary air mixed gas flow of the B layer burner mainly crosses the first level judgment surface, the second level judgment surface and the third level judgment surface, which is high fullness.
[0038] The single-layer primary air mixed gas flow is mainly in the streamline across the first level judgment surface and does not cross the second level judgment surface and the third level judgment surface, or the single-layer primary air mixed gas flow is mainly in the streamline and does not cross the first level judgment surface and crosses the second level judgment surface and the third level judgment surface, which is sub-fullness.
[0039] Specifically, when the single-layer combustor primary air nozzle mixed gas flow in the furnace is sub-fullness, it is divided into the following two cases. The first case is that the single-layer primary air mixed gas flow main streamline crosses the first level judgment surface and does not cross the second level judgment surface and the third level judgment surface. The second case is that the single-layer primary air mixed gas flow main streamline does not cross the first level judgment surface and crosses the second level judgment surface and the third level judgment surface.
[0040] In some embodiments, the single-layer primary air mixed gas flow main streamline schematic diagram of the front wall A layer combustor is as shown in Figure 1 At this time, the single-layer primary air mixed gas flow main streamline of the A layer combustor crosses the first level judgment surface and does not cross the second level judgment surface and the third level judgment surface, which is sub-fullness.
[0041] The single-layer primary air mixed gas flow main streamline does not cross the first level judgment surface and does not cross the second level judgment surface and / or the third level judgment surface, which is low fullness.
[0042] Specifically, when the single-layer combustor primary air nozzle mixed gas flow in the furnace is low fullness, it is divided into the following three cases. The first case is that the single-layer primary air mixed gas flow main streamline does not cross the first level judgment surface and the second level judgment surface and crosses the third level judgment surface. The second case is that the single-layer primary air mixed gas flow main streamline does not cross the first level judgment surface and the third level judgment surface and crosses the second level judgment surface. The third case is that the single-layer primary air mixed gas flow main streamline does not cross the first level judgment surface, the second level judgment surface and the third level judgment surface.
[0043] The single-layer primary air mixed gas flow main streamline is the region where 90% trajectories are concentrated, and the single-layer primary air mixed gas flow main streamline is obtained by a plume experiment or a spark experiment.
[0044] The front wall operating combustor average fullness is the average value of the fullness of all single-layer combustors of the front wall operating combustor, and the rear wall operating combustor average fullness is the average value of the fullness of all single-layer combustors of the rear wall operating combustor.
[0045] As shown in Figure 1 and Figure 2 , the front wall has three combustors of A layer combustor, C layer combustor and E layer combustor. The average value of the fullness of the three front wall single-layer combustors is the front wall operating combustor average fullness. The rear wall has two combustors of B layer combustor and D layer combustor. The average value of the fullness of the two rear wall single-layer combustors is the rear wall operating combustor average fullness.
[0046] The furnace mixing index is determined according to the product of the average fullness of the front wall operating burner and the average fullness of the rear wall operating burner; the low-sodium coal blending position is determined according to the ratio of the average fullness of the front wall operating burner and the average fullness of the rear wall operating burner. When the ratio of the average fullness of the front wall operating burner and the average fullness of the rear wall operating burner is greater than 1, the low-sodium coal is blended in the lower layer of the front wall; when the ratio of the average fullness of the front wall operating burner and the average fullness of the rear wall operating burner is less than 1, the low-sodium coal is blended in the lower layer of the rear wall; and when the ratio of the average fullness of the front wall operating burner and the average fullness of the rear wall operating burner is equal to 1, the low-sodium coal blending position is determined in combination with the furnace mixing index.
[0047] The following is specifically explained. When the single-layer burner fullness is set as high fullness, the single-layer burner fullness value is 3, that is, the single-layer mixing index at this time is 3; when the single-layer burner fullness is set as sub-fullness, the single-layer burner fullness value is 2, that is, the single-layer mixing index at this time is 2; and when the single-layer burner fullness is set as low fullness, the single-layer burner fullness value is 1, that is, the single-layer mixing index at this time is 1.
[0048] The furnace mixing index (hun) and the front-rear wall mixing ratio (Ω) are the judgment indexes of the overall mixing degree of the low-sodium coal blended primary air flow furnace.
[0049] Hun = average fullness of front wall operating burner * average fullness of rear wall operating burner
[0050] 9≥Hun>6: The mixing degree is relatively high, and the pollution of the furnace area to the tail flue is relatively light;
[0051] 6≥Hun>3: The mixing degree is general, the air flow mixing condition of the furnace area is not ideal, and the pollution of the platen superheater and the horizontal flue is aggravated;
[0052] 3≥Hun>1: The mixing degree is poor, and the pollution of the furnace area to the tail flue is heavy.
[0053] Ω = average fullness of front wall operating burner / average fullness of rear wall operating burner
[0054] Ω>1: The front wall fullness is higher than the rear wall, and a low proportion of low-sodium coal should be blended in the lower layer of the front wall;
[0055] Ω = 1: The front wall fullness is equivalent to the rear wall, and the low-sodium coal blending position is determined in combination with Hun;
[0056] Ω<1: The rear wall fullness is higher than the front wall, and a low proportion of low-sodium coal should be blended in the lower layer of the rear wall.
[0057] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the description of the specification, the illustrative description of the above terms can be directed to different embodiments or examples. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.
[0058] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.
[0059] Although embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.
Claims
1. A method for evaluating the judgment of low-sodium coal blending combustion position of front and back wall opposed wall boilers, characterized in that, The method comprises the following steps: (1) judging the fullness of the single-layer burner primary air nozzle mixed gas flow by three auxiliary judgment planes; (2) obtaining the average fullness of the front wall operating burner and the average fullness of the rear wall operating burner according to the fullness of the single-layer burner; (3) judging the furnace mixing index according to the product of the average fullness of the front wall operating burner and the average fullness of the rear wall operating burner; (4) judging the low-sodium coal blending position according to the ratio of the average fullness of the front wall operating burner and the average fullness of the rear wall operating burner, wherein the three auxiliary judgment planes comprise a first judgment plane, a second judgment plane and a third judgment plane, the first judgment plane is the middle section of the front and rear walls at the upper overfire air height, the second judgment plane is the middle section of the narrowest part of the arched flue, and the third judgment plane is the middle section in the horizontal flue height direction, when the ratio of the average fullness of the front wall operating burner and the average fullness of the rear wall operating burner is greater than 1, the low-sodium coal is blended in the front wall lower layer; when the ratio of the average fullness of the front wall operating burner and the average fullness of the rear wall operating burner is less than 1, the low-sodium coal is blended in the rear wall lower layer; and when the ratio of the average fullness of the front wall operating burner and the average fullness of the rear wall operating burner is equal to 1, the low-sodium coal blending position is determined in combination with the furnace mixing index.
2. The method of claim 1, wherein, The single-layer primary air mixed gas flow main flow line is high fullness when it crosses the first judgment plane and crosses the second judgment plane and / or the third judgment plane.
3. The method of claim 1, wherein, The single-layer primary air mixed gas flow main flow line is sub-fullness when it crosses the first judgment plane and does not cross the second judgment plane and the third judgment plane, or it does not cross the first judgment plane and crosses the second judgment plane and the third judgment plane.
4. The method of claim 1, wherein, The single-layer primary air mixed gas flow main flow line is low fullness when it does not cross the first judgment plane and does not cross the second judgment plane and / or the third judgment plane.
5. The method of any one of claims 2-4, wherein, The single-layer primary air mixed gas flow main flow line is the area where 90% trajectories are concentrated.
6. The method of claim 5, wherein, The single-layer primary air mixed gas flow main flow line is obtained by a plume experiment or a spark experiment.
7. The method of claim 1, wherein, When the fullness of the single-layer burner is high fullness, low-sodium coal blending is performed; when the fullness of the single-layer burner is low fullness, low-sodium coal blending is not performed.
8. The method of claim 1, wherein, The average fullness of the front wall operating burner is the average value of the fullness of all single-layer burners operating in the front wall, and the average fullness of the rear wall operating burner is the average value of the fullness of all single-layer burners operating in the rear wall.
Citation Information
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