Biomass coupling blending combustion power generation device

Abstract

The invention relates to the technical field of solid fuel combustion equipment, and discloses a biomass coupling blending combustion power generation device which comprises a biomass feeding device arranged on a combustor, the biomass feeding device comprises a biomass air pipe, a secondary air pipe and an auxiliary air nozzle, biomass in the biomass air pipe is hindered by the separation structure, so that the distribution condition of biomass particles is dense inside and sparse outside; the biomass air pipe is sleeved with the secondary air pipe, and a secondary air channel is formed between the secondary air pipe and the biomass air pipe; the auxiliary air nozzle is arranged on the combustor, and gas sprayed out of the auxiliary air nozzle is located on the outer side of biomass jet flow sprayed out of the biomass air pipe. Through the arrangement of the separation structure, biomass formed in the biomass air pipe is distributed in the radial direction of the biomass air pipe in the mode that the inner portion is thick and the outer portion is light, grading and concentrated combustion of the biomass are achieved, and the biomass burn-off rate is increased.

Description

Technical Field

[0001] The invention relates to the technical field of solid fuel combustion equipment, and in particular to a biomass coupled mixed combustion power generation device. Background Art

[0002] The co-firing of biomass in coal-fired power plants, i.e., coal-fired coupled with biomass power generation, is a comprehensive utilization of traditional energy and renewable energy. It can not only significantly reduce CO2 emissions, but also has the advantages of economy, high efficiency and environmental protection.

[0003] Existing biomass coupled co-firing power generation devices all use pneumatic conveying to spray biomass into the furnace from the boiler secondary air nozzle. The biomass flow field is not effectively coupled with the power field of the main combustion zone in the furnace. The wind speed and momentum of the biomass nozzle are low and the penetration is poor. Due to the high volatile matter and salt content of the biomass, part of the biomass burns near the nozzle, increasing the temperature of the water-cooled wall here, which easily causes the risk of coking. At the same time, the biomass conveying air volume is large and all is cold air, which reduces the combustion efficiency in the furnace. Summary of the invention

[0004] In order to solve the technical problems existing in the background technology, the present invention proposes a biomass coupled co-firing combustion power generation device.

[0005] The present invention proposes a biomass coupled mixed combustion power generation device, comprising a burner, the burner having a furnace like the existing burner, and the burner having a coal feed port, a plurality of primary air nozzles and a plurality of secondary air nozzles like the existing burner, and the difference from the prior art is that: it also includes a biomass feeding device arranged on the burner, the biomass feeding device includes a biomass air duct, a secondary air duct and an auxiliary air nozzle, wherein:

[0006] A separation structure is provided in the biomass air duct, and the separation structure blocks the biomass in the biomass air duct so as to achieve a distribution of biomass particles that is dense inside and sparse outside, and smaller biomass particles are located outside;

[0007] The secondary air duct is sleeved on the outside of the biomass air duct, and a secondary air channel is formed between the secondary air duct and the biomass air duct, and high-speed secondary air is present in the secondary air channel;

[0008] The auxiliary air nozzle is arranged on the burner, and the gas ejected from the auxiliary air nozzle is located on the outside of the biomass jet ejected from the biomass air duct. The flow rate of the airflow discharged from the secondary channel and the airflow discharged from the auxiliary air nozzle is greater than the speed of the biomass jet ejected from the biomass air duct.

[0009] The biomass is blown into the furnace by wind in the biomass air duct, and the rigidity and penetration of the biomass jet ejected from the biomass air duct are improved through the secondary air duct and the auxiliary air nozzle, thereby ensuring that the biomass can enter the middle of the furnace for combustion, improving the biomass burnout rate, and effectively preventing the biomass from burning near the nozzle water-cooled wall, which can effectively prevent the risk of coking of the water-cooled wall;

[0010] By pulling the high-speed secondary air and auxiliary air nozzles to eject airflow, the rigidity of biomass entering the furnace is improved, which can effectively reduce the amount of cold air for biomass transportation, improve the furnace efficiency of biomass coupled combustion boilers, and increase the amount of biomass combustion;

[0011] By setting the separation structure, the biomass formed in the biomass air duct is distributed in a form of dense inside and thin outside along its radial direction (dense inside and thin outside, i.e., the biomass density inside is large and the biomass density outside is small), thereby realizing the graded and concentrated combustion of the biomass and improving the biomass burnout rate.

[0012] As a further optimized solution of the present invention, the auxiliary air nozzle includes an upper auxiliary air nozzle and a lower auxiliary air nozzle arranged on the burner, the upper auxiliary air nozzle is located above the biomass air duct, and the lower auxiliary air nozzle is located below the biomass air duct, and the distance from the upper auxiliary air nozzle to the biomass air duct is equal to the distance from the lower auxiliary air nozzle to the biomass air duct, thereby further improving the rigidity of the biomass jet.

[0013] Preferably, the auxiliary air nozzle has a wind speed of 50-60 m / s. In some embodiments, the auxiliary air nozzle contains secondary air.

[0014] Preferably, the distance between the auxiliary air nozzle and the biomass air duct is 2.2D to 2.5D, where D is the diameter of the biomass air duct.

[0015] As a further optimized solution of the present invention, the gas flow rate in the secondary air channel is greater than the gas flow rate in the biomass air duct.

[0016] As a further optimized solution of the present invention, the discharge end of the biomass air duct is provided with a biomass expansion port, and the air outlet end of the secondary air duct is provided with a secondary air expansion port. As a further optimized solution of the present invention, the secondary air expansion port is sleeved on the outside of the biomass expansion port and the air outlet end of the secondary air expansion port extends out of the biomass expansion port;

[0017] Through the expansion setting and in combination with the above-mentioned features, the outlet biomass jet area of ​​the biomass combustion device forms a stable jet penetration area and an outer ring recirculation area. The outer ring recirculation area can draw the peripheral high-temperature smoke into the biomass jet area, heat the biomass jet, promote biomass ignition, and ensure the stability of the biomass flame.

[0018] As a further optimized solution of the present invention, the expansion angle of the biomass expansion is smaller than the expansion angle of the secondary air expansion. Specifically, the expansion angle of the biomass expansion ranges from 10° to 25°, and the expansion angle of the secondary air expansion ranges from 15° to 25°.

[0019] As a further optimized solution of the present invention, the separation structure is located outside the secondary air duct, and the separation structure is close to the secondary air duct.

[0020] As a further optimized solution of the present invention, the separation mechanism includes a first conical protrusion arranged on the inner wall of the biomass air duct, and the outer diameter of the first conical protrusion gradually decreases from an end close to the outlet end of the biomass air duct to an end away from the outlet end of the biomass air duct. In some technical solutions, the angle between the generatrix of the second conical protrusion and the axis of the biomass air duct ranges from 15° to 25°.

[0021] On the basis of the above technical solution, as a further optimized solution of the present invention, the separation mechanism further includes a second conical protrusion, the second conical protrusion is closer to the outlet end of the biomass branch pipe relative to the first conical protrusion, and the outer diameter of the second conical protrusion gradually increases from the end close to the outlet end of the biomass air duct to the side away from the outlet end of the biomass air duct. In some technical solutions, the angle between the generatrix of the second conical protrusion and the axis of the biomass air duct is in the range of 15° to 25°.

[0022] As a further optimized solution of the present invention, the separation mechanism further comprises an annular connection arranged between the first conical protrusion and the second conical protrusion, and the outer diameters of the annular connection are equal. As a further optimized solution of the present invention, the first conical protrusion and the second conical protrusion are symmetrical relative to the annular connection.

[0023] As a further optimized solution of the present invention, the length of the annular connection is 0.1D to 0.2D, where D is the diameter of the biomass air duct.

[0024] As a further optimized solution of the present invention, the biomass feeding device forms a first airflow, the airflow in the burner is a second airflow, and the first airflow and the second airflow are sprayed into the furnace at an angle of 3° to 6°.

[0025] The circle circumscribed by the first airflow is coaxial with the circle circumscribed by the second airflow, and the diameter of the circle circumscribed by the first airflow is smaller than the diameter of the circle circumscribed by the second airflow.

[0026] In the present invention, the proposed biomass coupled mixed combustion power generation device blows the biomass into the furnace through wind in the biomass air duct, and improves the rigidity and penetration of the biomass jet ejected from the biomass air duct through the secondary air duct and the auxiliary air nozzle, thereby ensuring that the biomass can enter the middle of the furnace for combustion, improving the biomass burnout rate, and effectively preventing the biomass from burning near the nozzle water-cooled wall, which can effectively prevent the risk of coking of the water-cooled wall;

[0027] By pulling the high-speed secondary air and auxiliary air nozzles to eject airflow, the rigidity of biomass entering the furnace is improved, which can effectively reduce the amount of cold air for biomass transportation, improve the furnace efficiency of biomass coupled combustion boilers, and increase the amount of biomass combustion;

[0028] By setting the separation structure, the biomass formed in the biomass air duct is distributed in a form of dense inside and thin outside along its radial direction (dense inside and thin outside, i.e., the distance between the internal biomass particles is small, and the distance between the external biomass particles is large), thereby realizing the classification and centralized combustion of the biomass and improving the biomass burnout rate.

[0029] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the present invention;

[0031] Figure 2 This is a schematic diagram of the biomass air duct structure of the present invention;

[0032] Figure 3 This is a schematic diagram of the relative position structure of the first airflow and the second airflow in the present invention;

[0033] In the figure: 1. burner; 2. biomass air duct; 3. secondary air duct; 4. upper auxiliary air nozzle; 5. lower auxiliary air nozzle; 6. biomass expansion; 7. secondary air expansion; 8. separation structure; 80. first conical protrusion; 81. second conical protrusion; 82. annular connection; 9. first airflow; 10. second airflow. DETAILED DESCRIPTION

[0034] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar symbols throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0035] like Figure 1-2As shown, a biomass coupled co-combustion combustion power generation device includes a burner 1. The burner 1 has a furnace like the existing burner 1. Like the existing burner 1, the burner 1 has a coal inlet, a plurality of primary air nozzles and a plurality of secondary air nozzles (not shown in the figure), and also includes a biomass feeding device arranged on the burner 1. The biomass feeding device transports the biomass into the furnace. The biomass feeding device includes a biomass air duct 2, a secondary air duct 3 and an auxiliary air nozzle, wherein:

[0036] A separation structure 8 is provided in the biomass air duct 2, and the separation structure 8 blocks the biomass in the biomass air duct 2 to achieve a distribution of biomass particles that is dense inside and sparse outside (i.e., the spacing between biomass particles located in the middle is smaller than the spacing between biomass particles located outside), and the smaller biomass particles are located outside;

[0037] The secondary air duct 3 is sleeved on the outer side of the biomass air duct 2, and a secondary air channel is formed between the secondary air duct 3 and the biomass air duct 2. There is high-speed secondary air in the secondary air channel. Specifically, the gas flow rate in the secondary air channel is greater than the gas flow rate in the biomass air duct 2.

[0038] The auxiliary air nozzle is arranged on the burner 1, and the gas ejected from the auxiliary air nozzle is located on the outside of the biomass jet ejected from the biomass air duct 2. The flow rate of the airflow discharged from the secondary channel and the airflow discharged from the auxiliary air nozzle is greater than the speed of the biomass jet ejected from the biomass air duct 2, thereby achieving the gas discharged from the secondary channel and the gas discharged from the auxiliary air nozzle to provide a traction effect on the biomass jet.

[0039] The biomass is blown into the furnace by wind in the biomass air duct 2, and the rigidity and penetration of the biomass jet ejected from the biomass air duct 2 are improved through the secondary air duct 3 and the auxiliary air nozzle, thereby ensuring that the biomass can enter the middle of the furnace for combustion, improving the biomass burnout rate, and effectively preventing the biomass from burning near the nozzle water-cooled wall, which can effectively prevent the risk of coking of the water-cooled wall;

[0040] By pulling the high-speed secondary air and auxiliary air nozzles to eject airflow, the rigidity of biomass entering the furnace is improved, which can effectively reduce the amount of cold air for biomass transportation, improve the furnace efficiency of biomass coupled combustion boilers, and increase the amount of biomass combustion;

[0041] By setting the separation structure 8, the biomass formed in the biomass air duct 2 is distributed in a form of dense inside and thin outside along its radial direction (dense inside and thin outside, i.e., the biomass density inside is large and the biomass density outside is small), thereby realizing the classification and centralized combustion of the biomass and improving the biomass burnout rate.

[0042] Preferably, in some embodiments, the auxiliary air nozzle includes an upper auxiliary air nozzle 4 and a lower auxiliary air nozzle 5 arranged on the burner 1, the upper auxiliary air nozzle 4 is located above the biomass air duct 2, the lower auxiliary air nozzle 5 is located below the biomass air duct 2, and the distance from the upper auxiliary air nozzle 4 to the biomass air duct 2 is equal to the distance from the lower auxiliary air nozzle 5 to the biomass air duct 2, and the rigidity of the biomass jet is further improved by the auxiliary traction airflow distributed in the upper and lower layers of the biomass jet.

[0043] Preferably, the wind speed of the auxiliary air nozzle is 50-60 m / s. In some embodiments, the auxiliary air nozzle contains secondary air, and the temperature of the secondary air is relatively high, which further improves the combustion of biomass in the furnace. The distance L1 from the auxiliary air nozzle to the biomass air duct 2 is 2.2D-2.5D, where D is the diameter of the biomass air duct 2. Within the above speed range and the distance range from the auxiliary air nozzle to the biomass air duct 2, the combustion of biomass by high-temperature gas in the furnace is facilitated while achieving the traction effect on the biomass jet.

[0044] In some embodiments, preferably, the discharge end of the biomass air duct 2 is provided with a biomass expansion port 6, and the air outlet end of the secondary air duct 3 is provided with a secondary air expansion port 7. As a further optimized solution of the present invention, the secondary air expansion port 7 is sleeved on the outside of the biomass expansion port 6 and the air outlet end of the secondary air expansion port 7 is located on the outside of the biomass expansion port 6. Since the gas temperature in the secondary air duct 3 is higher than the temperature of the material in the biomass air duct 2, and due to the separation structure 8 and the expansion structure setting, the biomass jet is further separated for a second time;

[0045] At the same time, through the expansion setting and combined with the above-mentioned characteristics, the outlet biomass jet area of ​​the biomass combustion device forms a stable jet penetration area and an outer ring recirculation area. The outer ring recirculation area can draw the peripheral high-temperature smoke into the biomass jet area, heat the biomass jet, promote biomass ignition, and ensure the stability of the biomass flame.

[0046] As a further optimized solution of the present invention, the expansion angle of the biomass expansion port 6 is smaller than the expansion angle of the secondary air expansion port 7. Specifically, the expansion angle α of the biomass expansion port 6 ranges from 10° to 25°, and the expansion angle β of the secondary air expansion port 7 ranges from 15° to 25°.

[0047] Preferably, if Figure 2 As shown, the axial length of the biomass expansion port 6 is 0.75 to 0.8 times the axial length of the secondary air expansion port, and the secondary air expansion port 7 has a portion extending outward relative to the biomass expansion port 6 , and the biomass expansion port 6 is closer to the separation structure 8 relative to the secondary air expansion port 7 .

[0048] On the basis of the above technical solution, preferably, Figure 2As shown, the cross-sectional area of ​​the secondary air duct 3 is 0.5-0.75 times the cross-sectional area of ​​the biomass air duct 2 .

[0049] like Figure 2 As shown, as a further optimized solution of the present invention, the separation structure 8 is located on the outside of the secondary air duct 3, and the separation structure 8 is close to the secondary air duct 3. The temperature of the biomass tube covered on the inner side of the secondary air duct 3 is higher than the temperature of the part located on the outer side of the secondary air duct 3, which further facilitates the separation and jetting of the biomass.

[0050] Preferably, the separation mechanism comprises a first conical protrusion 80 arranged on the inner wall of the biomass air duct 2, that is, Figure 2 In the AB section, the outer diameter of the first conical protrusion 80 gradually decreases from the end close to the outlet end to the end far away from the outlet end. In some technical solutions, the angle between the generatrix of the second conical protrusion 81 and the axis of the biomass air duct 2 is in the range of 15° to 25°;

[0051] The separation mechanism further includes a second conical protrusion 81 (i.e. Figure 2 CD segment in the figure), the second conical protrusion 81 is closer to the outlet end of the biomass branch pipe relative to the first conical protrusion 80, and the outer diameter of the second conical protrusion 81 gradually increases from the end close to the outlet end of the biomass air duct 2 to the side away from the outlet end of the biomass air duct 2, and the angle between the generatrix of the second conical protrusion 81 and the axis of the biomass air duct 2 is in the range of 15° to 25°; the separation mechanism also includes an annular connection 82 (i.e., a ring-shaped connection 82) arranged between the first conical protrusion 80 and the second conical protrusion 81 Figure 2 The outer diameter of the annular connection 82 is equal, and the length of the annular connection 82 is 0.1D to 0.2D, where D is the diameter of the biomass air duct 2. Figure 2 As shown, a channel with gradually decreasing aperture-unchanged aperture-gradually increasing aperture is realized, which is convenient for the diversion of biomass particles. The first conical protrusion 80 and the second conical protrusion 81 are symmetrical relative to the annular connection 82. The separation structure 8 is arranged to facilitate the separation of biomass particles to a certain extent. In order to achieve better separation of biomass particles, preferably, the thickness S of the annular connection 82 is (0.1 to 0.2) times the diameter D of the biomass air duct 2. Figure 2 As shown, the maximum distance L2 from the biomass expansion port 6 to the separation structure 8 is 2.5 to 3 times D (D is the diameter of the biomass tube).

[0052] like Figure 3As shown, preferably, the biomass feeding device forms a first airflow 9, and the airflow in the burner 1 is a second airflow 10. The first airflow 9 and the second airflow 10 are sprayed into the furnace at an angle of 3° to 6°. The circle circumscribed by the first airflow 9 is coaxial with the circle circumscribed by the second airflow 10, and the diameter of the circle circumscribed by the first airflow 9 is smaller than the diameter of the circle circumscribed by the second airflow 10. The biomass jet is guided into the center of the upstream flame, so that the biomass quickly ignites and burns in the middle of the furnace, which can effectively improve the biomass burnout rate.

[0053] The present invention is applied to a 660Mw four-corner tangential boiler, and relevant data of the boiler with the same 10% calorific value of biomass mixed before and after the transformation, such as ash fly ash carbon content, flue gas temperature, large slag carbon content, etc., are compared. Through data analysis, the biomass burnout rate is improved by about 3% after the present invention is adopted compared with that before the transformation: after the transformation, after a long period of operation, the problem of coking and high-temperature corrosion of the water-cooled wall at the burner outlet is basically not found within one maintenance cycle, which basically solves the risk of coking and corrosion of the water-cooled wall near the burner nozzle caused by the mixing and burning of a large amount of biomass.

[0054] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0055] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0056] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0058] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A biomass coupled combustion power generation device, comprising a burner (1), the burner (1) having a furnace like the existing burner (1), and having multiple coal inlets, multiple primary air nozzles and multiple secondary air nozzles like the existing burner (1), characterized in that: It also includes a biomass feeding device arranged on the burner (1), the biomass feeding device comprising a biomass air duct (2), a secondary air duct (3) and an auxiliary air nozzle, wherein: A separation structure (8) is provided in the biomass air duct (2), and the separation structure (8) blocks the biomass in the biomass air duct (2) so as to achieve a distribution of biomass particles that is dense inside and sparse outside; The secondary air duct (3) is sleeved on the outside of the biomass air duct (2), and a secondary air channel is formed between the secondary air duct (3) and the biomass air duct (2), and high-speed secondary air is present in the secondary air channel; The auxiliary air nozzle is arranged on the burner (1), and the gas ejected from the auxiliary air nozzle is located outside the biomass jet ejected from the biomass air duct (2), and the flow rate of the air flow discharged from the secondary channel and the air flow discharged from the auxiliary air nozzle is greater than the speed of the biomass jet ejected from the biomass air duct (2).

2. The biomass coupled combustion power generation device according to claim 1 is characterized in that: The auxiliary air nozzle comprises an upper auxiliary air nozzle (4) and a lower auxiliary air nozzle (5) arranged on the burner (1), wherein the upper auxiliary air nozzle (4) is located above the biomass air duct (2), and the lower auxiliary air nozzle (5) is located below the biomass air duct (2).

3. The biomass coupled co-firing combustion power generation device according to claim 1 is characterized in that: The wind speed of the auxiliary wind nozzle is 50-60m / s.

4. The biomass coupled combustion power generation device according to claim 1 is characterized in that: The distance between the auxiliary air nozzle and the biomass air duct (2) is 2.2D to 2.5D.

5. The biomass coupled combustion power generation device according to claim 1 is characterized in that: The discharge end of the biomass air duct (2) is provided with a biomass expansion port (6), and the air outlet end of the secondary air duct (3) is provided with a secondary air expansion port (7).

6. The biomass coupled combustion power generation device according to claim 5 is characterized in that: The secondary air expansion opening (7) is sleeved on the outside of the biomass expansion opening (6), and the air outlet end of the secondary air expansion opening (7) extends out of the biomass expansion opening (6).

7. The biomass coupled combustion power generation device according to claim 5 is characterized in that: The expansion angle of the biomass expansion port (6) is smaller than the expansion angle of the secondary air expansion port (7).

8. The biomass coupled combustion power generation device according to claim 7 is characterized in that: The expansion angle of the biomass expansion port (6) is in the range of 10° to 25°, and the expansion angle of the secondary air expansion port (7) is in the range of 15° to 25°.

9. The biomass coupled co-firing combustion power generation device according to claim 1, characterized in that: The separation structure (8) is located outside the secondary air duct (3), and the separation structure (8) is close to the secondary air duct (3).

10. The biomass coupled combustion power generation device according to claim 9, characterized in that: The separation mechanism comprises a first conical protrusion (80) arranged on the inner wall of the biomass air duct (2), and the outer diameter of the first conical protrusion (80) gradually decreases from an end close to the outlet end of the biomass air duct (2) to an end far from the outlet end of the biomass air duct (2).

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