A material distribution system for coal-fired units with large proportions of biomass

Abstract

The present invention discloses a material distribution system for coal-fired units for large-proportion biomass blending and burning. The system comprises a biomass fuel output pipeline, a weighing belt conveyor, a distributor, a first grinding drum, a second grinding drum, a first airflow emitter, a second airflow emitter, a first fan, a second fan, a first one-to-two equalizing device, a second one-to-two equalizing device, a first biomass blending and burning coupler, a second biomass blending and burning coupler, a third biomass blending and burning coupler, a fourth biomass blending and burning coupler and a furnace. The system can ensure that biomass powder of each burner is evenly distributed when a large proportion of biomass is blended and burned.

Description

Technical Field

[0001] The invention belongs to the field of biomass blending and burning, and relates to an incoming material equalization system for blending and burning biomass in large proportion in a coal-fired unit. Background Art

[0002] The technology for co-firing biomass direct-fired coupled coal-fired units started relatively late in China, but its application is more mature abroad. A complete biomass co-firing system includes a discharge unit, screening unit, silo storage unit, furnace silo and pulverizing unit, biomass powder transportation and coupling unit, and conveying equipment between units. The biomass pulverizing and coupling unit is crucial as it directly affects the operating status of the original coal-fired unit. Currently, the commonly used solution for evenly dividing the incoming material for the biomass powder pulverizing and coupling unit is: biomass powder falls into the fan outlet and is blown into the primary air duct. The primary air duct is then divided into two by a trouser pipe in front of the furnace and enters the raw coal pulverized pipeline or burner.

[0003] For coal-fired units, when burning biomass in large proportions, it is very important to ensure that the biomass powder is evenly distributed in each burner. If the distribution deviation of biomass powder in each burner is large, it will lead to partial burning in the furnace, local overheating, local coking, severe local high-temperature corrosion, NO X A series of problems, such as increased production and the easy accumulation and clogging of individual biomass powder pipes, have affected the safe and environmentally friendly operation of the original coal-fired boiler. For coal-fired units, the distribution of pulverized coal at the outlet of the direct-blowing pulverizing system is mainly guaranteed by a rotary separator or distributor, and a lot of research and development and improvements have been made in this area. However, for biomass blending systems, there is no air supply in the biomass mill, and the biomass powder in the mill falls into the air supply system by gravity. Moreover, the biomass powder is filamentous, lighter than coal particles, has good airflow tracking, low inertia, and is prone to filamentation. Due to the physical properties of biomass powder, its incoming material distribution system cannot draw on the rotary separators and various types of distributors of coal-fired units. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a material distribution system for coal-fired units with large proportions of biomass blending, which can ensure uniform distribution of biomass powder in each burner when large proportions of biomass blending are blended.

[0005] To achieve the above-mentioned object, the incoming material equalization system for large-proportion biomass co-firing in a coal-fired unit according to the present invention comprises a biomass fuel output pipeline, a weighing belt conveyor, a distributor, a first grinding drum, a second grinding drum, a first airflow emitter, a second airflow emitter, a first fan, a second fan, a first one-to-two equalization device, a second one-to-two equalization device, a first biomass co-firing coupler, a second biomass co-firing coupler, a third biomass co-firing coupler, a fourth biomass co-firing coupler, and a furnace;

[0006] The biomass fuel output pipeline is connected to the inlet of the weighing belt conveyor, the outlet of the weighing belt conveyor is connected to the inlet of the distributor, the first outlet of the distributor is connected to the inlet of the first airflow emitter via the first grinding cylinder, the second outlet of the distributor is connected to the inlet of the second airflow emitter via the second grinding cylinder 4, the outlet of the first fan is connected to the inlet of the first airflow emitter, the outlet of the second fan is connected to the inlet of the second airflow emitter, the outlet of the first airflow emitter is connected to the inlet of the first one-to-two equalizing device, and the outlet of the second airflow emitter is connected to the inlet of the second one-to-two equalizing device;

[0007] The first outlet of the first one-divide-two equal-dividing device is connected to the inlet of the first biomass co-combustion coupler, the second outlet of the first one-divide-two equal-dividing device is connected to the inlet of the second biomass co-combustion coupler, the first outlet of the second one-divide-two equal-dividing device is connected to the inlet of the third biomass co-combustion coupler, and the second outlet of the second one-divide-two equal-dividing device is connected to the inlet of the fourth biomass co-combustion coupler. The first biomass co-combustion coupler, the second biomass co-combustion coupler, the third biomass co-combustion coupler and the fourth biomass co-combustion coupler are all arranged on the furnace.

[0008] The first blower and the second blower are both Roots blowers.

[0009] The outlet of the first airflow emitter is connected to the inlet of the first one-to-two equal-dividing device through the first main powder pipe.

[0010] The outlet of the second airflow emitter is connected to the inlet of the second one-to-two equal-dividing device through the second main powder pipe.

[0011] The length of the first main powder pipe is (5-10)D1, where D is the inner diameter of the first main powder pipe.

[0012] The length of the second main powder pipe is (5-10)D2, where D2 is the inner diameter of the second main powder pipe.

[0013] The distributor has the function of even distribution of materials.

[0014] The first airflow emitter and the second airflow emitter adopt a Venturi structure.

[0015] The present invention has the following beneficial effects:

[0016] The material distribution system for large-proportion biomass blending in coal-fired units described in the present invention ensures that the feed amounts of the first grinding drum and the second grinding drum are consistent during specific operation through a distributor. The biomass material is cut into biomass powder in the first grinding drum and the second grinding drum, and then the air flow emitter accelerates the uniform mixing of the air and powder phases. The biomass material then enters the four biomass blending couplers through the first one-to-two equalizing device and the second one-to-two equalizing device, so as to fully consider the integrity of the system and the physical properties of the biomass powder, and ensure that the biomass powder of each burner is evenly distributed when biomass is blended in a large proportion. The system has a simple structure, is easy to operate, and is extremely practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention.

[0018] Among them, 1 is a weighing belt conveyor, 2 is a distributor, 3 is the first grinding drum, 4 is the second grinding drum, 5 is the first air flow emitter, 6 is the second air flow emitter, 7 is the first fan, 8 is the second fan, 9 is the first one-to-two equalizing device, 10 is the second one-to-two equalizing device, 11 is the first biomass co-combustion coupler, 12 is the second biomass co-combustion coupler, 13 is the third biomass co-combustion coupler, 14 is the fourth biomass co-combustion coupler, and 15 is the furnace. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments, and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0020] The accompanying drawings illustrate schematic diagrams of the structures of the disclosed embodiments of the present invention. These figures are not drawn to scale; for the purpose of clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0021] refer to Figure 1The material distribution system for large-scale biomass co-firing in a coal-fired unit according to the present invention comprises a weighing belt conveyor 1, a distributor 2, a first grinding drum 3, a second grinding drum 4, a first airflow emitter 5, a second airflow emitter 6, a first fan 7, a second fan 8, a first one-to-two equalizing device 9, a second one-to-two equalizing device 10, a first biomass co-firing coupler 11, a second biomass co-firing coupler 12, a third biomass co-firing coupler 13, a fourth biomass co-firing coupler 14, and a furnace 15.

[0022] The biomass fuel output pipeline is connected to the inlet of the weighing belt conveyor 1, the outlet of the weighing belt conveyor 1 is connected to the inlet of the distributor 2, the first outlet of the distributor 2 is connected to the inlet of the first air flow emitter 5 through the first grinding cylinder 3, the second outlet of the distributor 2 is connected to the inlet of the second air flow emitter 6 through the second grinding cylinder 4, the outlet of the first fan 7 is connected to the inlet of the first air flow emitter 5, the outlet of the second fan 8 is connected to the inlet of the second air flow emitter 6, the outlet of the first air flow emitter 5 is connected to the inlet of the first one-to-two equal distribution device 9 through the first main powder pipe, and the outlet of the second air flow emitter 6 is connected to the inlet of the second one-to-two equal distribution device 10 through the second main powder pipe.

[0023] The first outlet of the first one-divide-two equalizing device 9 is connected to the inlet of the first biomass co-combustion coupler 11, the second outlet of the first one-divide-two equalizing device 9 is connected to the inlet of the second biomass co-combustion coupler 12, the first outlet of the second one-divide-two equalizing device 10 is connected to the inlet of the third biomass co-combustion coupler 13, and the second outlet of the second one-divide-two equalizing device 10 is connected to the inlet of the fourth biomass co-combustion coupler 14. The first biomass co-combustion coupler 11, the second biomass co-combustion coupler 12, the third biomass co-combustion coupler 13 and the fourth biomass co-combustion coupler 14 are all arranged on the furnace 15.

[0024] The biomass fuel enters the distributor 2 via a weighing belt conveyor 1. The distributor 2 has a uniform distribution function, ensuring a consistent feed rate between the first and second grinding drums 3 and 4. The biomass is cut into biomass powder inside the first and second grinding drums 3 and 4, and then falls by gravity into the first and second airflow emitters 5 and 6, respectively. The first and second airflow emitters 5 and 6 use a Venturi structure. The air output by the first fan 7 enters the first airflow emitter 5, and the air output by the second fan 8 enters the second airflow emitter 6. The first and second airflow emitters 5 and 6 ensure rapid and uniform mixing of the biomass powder and air. Carried by the positive pressure airflow, the biomass powder enters the first one-to-two equal-dividing device 9 and the second one-to-two equal-dividing device 10 respectively, and then enters the first biomass blending and burning coupler 11, the second biomass blending and burning coupler 12, the third biomass blending and burning coupler 13 and the fourth biomass blending and burning coupler 14 respectively through four powder branch pipes, and is mixed with the raw coal powder airflow in the first biomass blending and burning coupler 11, the second biomass blending and burning coupler 12, the third biomass blending and burning coupler 13 and the fourth biomass blending and burning coupler 14, and then is sent into the furnace 15 for combustion.

[0025] It should be noted that the present invention utilizes a distributor 2 to ensure a consistent amount of biomass fuel entering the first and second grinding drums 3, 4. Furthermore, based on the characteristics of biomass powder, such as low density, low inertia, good airflow tracking, and easy threading, the following two measures are adopted: the length of the first main powder pipe between the first airflow emitter 5 and the first one-to-two equalizing device 9 is (5-10) D1, where D is the inner diameter of the first main powder pipe; and the length of the second main powder pipe between the second airflow emitter 6 and the second one-to-two equalizing device 10 is (5-10) D2, where D2 is the inner diameter of the second main powder pipe. These measures enhance the uniformity of the two-phase mixing of biomass powder and air at the inlets of the first and second one-to-two equalizing devices 9, 10. Due to the high two-phase filling and uniformity within the first and second main powder pipes, even distribution of biomass powder can be achieved by adjusting the left and right swinging of the internal baffles of the first and second one-to-two equalizing devices 9, 10.

Claims

1. A material distribution system for coal-fired units with large proportions of biomass, characterized by: It comprises a biomass fuel output pipeline, a weighing belt conveyor (1), a distributor (2), a first grinding drum (3), a second grinding drum (4), a first airflow emitter (5), a second airflow emitter (6), a first fan (7), a second fan (8), a first one-to-two equalizing device (9), a second one-to-two equalizing device (10), a first biomass blending and burning coupler (11), a second biomass blending and burning coupler (12), a third biomass blending and burning coupler (13), a fourth biomass blending and burning coupler (14) and a furnace (15); The biomass fuel output pipeline is connected to the inlet of the weighing belt conveyor (1), the outlet of the weighing belt conveyor (1) is connected to the inlet of the distributor (2), the first outlet of the distributor (2) is connected to the inlet of the first airflow emitter (5) via the first grinding cylinder (3), the second outlet of the distributor (2) is connected to the inlet of the second airflow emitter (6) via the second grinding cylinder (4), the outlet of the first fan (7) is connected to the inlet of the first airflow emitter (5), the outlet of the second fan (8) is connected to the inlet of the second airflow emitter (6), the outlet of the first airflow emitter (5) is connected to the inlet of the first one-to-two equalizing device (9), and the outlet of the second airflow emitter (6) is connected to the inlet of the second one-to-two equalizing device (10); The first outlet of the first one-divide-two equalizing device (9) is communicated with the inlet of the first biomass blending and burning coupler (11), the second outlet of the first one-divide-two equalizing device (9) is communicated with the inlet of the second biomass blending and burning coupler (12), the first outlet of the second one-divide-two equalizing device (10) is communicated with the inlet of the third biomass blending and burning coupler (13), the second outlet of the second one-divide-two equalizing device (10) is communicated with the inlet of the fourth biomass blending and burning coupler (14), and the first biomass blending and burning coupler (11), the second biomass blending and burning coupler (12), the third biomass blending and burning coupler (13) and the fourth biomass blending and burning coupler (14) are all arranged on the furnace (15).

2. The material distribution system for coal-fired units with large proportions of biomass as claimed in claim 1 is characterized in that: The first blower (7) and the second blower (8) are both Roots blowers.

3. The material distribution system for coal-fired units with large proportions of biomass as claimed in claim 1 is characterized in that: The outlet of the first airflow emitter (5) is connected to the inlet of the first one-to-two equal-dividing device (9) via the first main powder pipe.

4. The material distribution system for coal-fired units with large proportions of biomass as claimed in claim 3 is characterized in that: The outlet of the second airflow emitter (6) is connected to the inlet of the second one-to-two equal-dividing device (10) via the second main powder pipe.

5. The material distribution system for coal-fired units with large proportions of biomass as claimed in claim 3 is characterized in that: The length of the first main powder pipe is (5-10)D1, where D is the inner diameter of the first main powder pipe.

6. The incoming material equalization system for coal-fired units with large proportions of biomass blending according to claim 4 is characterized in that: The length of the second main powder pipe is (5-10)D2, where D2 is the inner diameter of the second main powder pipe.

7. The material distribution system for coal-fired units with large proportions of biomass as claimed in claim 1 is characterized in that: The distributor (2) has the function of evenly distributing the material.

8. The material distribution system for coal-fired units with large proportions of biomass as claimed in claim 1 is characterized in that: The first airflow emitter (5) and the second airflow emitter (6) adopt a Venturi structure.

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