A biomass powder-making and conveying device and a combustion system

Abstract

The present application relates to a biomass powder making and conveying device and a combustion system, belonging to the technical field of biomass combustion. The conveying device includes a biomass crusher, a powder conveying pipe, a Venturi tube and an air guiding pipe. A screen is installed at the bottom of the biomass crusher; the powder conveying pipe is connected to a feeding component, and the feeding component is connected to the bottom of the biomass crusher; one end of the powder conveying pipe is connected to a biomass burner for burning biomass powder, and the other end is connected to a high-pressure blower; one end of the Venturi tube is connected to a bypass branch pipe, the bypass branch pipe is connected to the end of the powder conveying pipe close to the high-pressure blower, and the other end is connected to the end of the powder conveying pipe far from the high-pressure blower; one end of the air guiding pipe is connected to the inner cavity of the biomass crusher, and the other end is inserted into the throat of the Venturi tube for forming a negative pressure at the throat of the Venturi tube. The present application has the effect of reducing the operation cost and the later maintenance cost of the powder making and conveying device.

Description

Technical Field

[0001] The present application relates to the technical field of biomass combustion, and in particular, to a biomass pulverizing and conveying device and a combustion system. Background Art

[0002] With the proposal of the dual-carbon goal, coal-fired power plants are urgently required to reduce carbon emissions. Since the reserves of agricultural and forestry biomass resources in China are rich, biomass, as a renewable energy with zero carbon emissions, has broad application prospects and can be used as an alternative energy to coal. Therefore, the coupling of biomass combustion in large coal-fired units has increasingly become a widespread demand. Most large coal-fired units are pulverized coal furnaces, which have high requirements for the fineness of the pulverized coal fed. The typical particle size of the pulverized coal entering the furnace is about 50 - 100 μm. Although the combustion characteristics of biomass are significantly better than those of coal, biomass powder also needs to be crushed into smaller particle sizes to achieve full combustion in the pulverized coal furnace.

[0003] At present, the technological routes for biomass pulverization are as follows: (1) Co-grinding with a coal mill, where the crushed biomass particles are made into biomass powder, the biomass powder is then pelletized, and the pelletized material is ground with coal in the coal mill and then sent into the furnace. Since biomass is fibrous, problems such as a decrease in the output of the coal mill will occur during the co-grinding process with coal; (2) Using a separate biomass mill, where the formed biomass particles are sent into the biomass mill to be ground into powder. This method is relatively reliable, but still requires the purchase of biomass particles and the construction of a new biomass powder storage bin.

[0004] Using a biomass crusher to crush biomass raw materials into powder and then pneumatically conveying it to a biomass burner for combustion is a technically simpler process.

[0005] In view of the above-related technologies, the inventor found the following defects: During the process of pulverizing biomass with a biomass crusher, since a screen is installed at the bottom of the biomass crusher, in order to ensure the output, an induced draft fan needs to be installed to form a negative pressure at the bottom of the screen; due to the use of the induced draft fan, the operating cost and the later maintenance cost of the pulverizing and conveying system will be relatively high. Summary of the Invention

[0006] In order to reduce the operating cost and the later maintenance cost of the pulverizing and conveying system, the present application provides a biomass pulverizing and conveying device and a combustion system.

[0007] In a first aspect, a biomass pulverizing and conveying device provided by the present application adopts the following technical solutions:

[0008] A biomass pulverizing and conveying device includes:

[0009] A biomass crusher for crushing biomass raw materials and outputting biomass powder;

[0010] A screen is installed at the bottom of the biomass grinder and is used to filter biomass powder.

[0011] A feeding component is installed at the bottom of the biomass grinder and is placed on the side of the screen away from the feeding port of the biomass grinder. It is used for continuous and stable feeding and to isolate the leakage of air from the cavity of the biomass grinder.

[0012] A powder conveying pipe has one end connected to a biomass burner for burning biomass powder and is used to convey biomass powder. The feeding component is in communication with the powder conveying pipe, and the feeding component is also used to isolate the air flow in the powder conveying pipe from flowing into the cavity of the biomass grinder.

[0013] A high-pressure blower has its air outlet connected to the other end of the powder conveying pipe and is used to provide high-pressure air.

[0014] A Venturi tube has one end connected to a bypass branch pipe. The bypass branch pipe is connected to the end of the powder conveying pipe close to the high-pressure blower, and the other end is connected to the end of the powder conveying pipe away from the high-pressure blower.

[0015] An air guiding pipe has one end connected to the cavity of the biomass grinder and is connected at a position on the side of the screen away from the feeding port of the biomass grinder. The other end is inserted into the throat of the Venturi tube and is used to form a negative pressure at the throat of the Venturi tube.

[0016] By adopting the above technical solution, biomass raw materials are fed into the top feeding port of the biomass grinder, screened by the screen, and the screened biomass powder enters the powder conveying pipe through the feeding component and is carried by the high-pressure air generated by the high-pressure blower and sent into the biomass burner for combustion. Since the pressure loss caused by the feeding component during feeding is large enough, it is sufficient to form a negative pressure at the throat of the Venturi tube, and a wind flowing towards the outlet of the Venturi tube is formed in the center of the air guiding pipe, so that the air in the lower cavity of the biomass grinder can be continuously sucked, thereby improving the powder making efficiency. Since there is no need to install an induced draft fan, the operation cost and the later maintenance cost of the powder making and conveying device are reduced.

[0017] Optionally, a first valve is installed on the bypass branch pipe, and the first valve is used to control the wind pressure and flow rate in the bypass branch pipe.

[0018] A second valve is installed on the powder conveying pipe, and the second valve is placed on the side of the bypass branch pipe away from the high-pressure blower. The second valve is used to control the wind pressure and flow rate in the powder conveying pipe.

[0019] Optionally, the diameter of the cross-section of the throat of the Venturi tube is 1 / 5 - 1 / 10 of the diameter of the cross-section of the inlet of the Venturi tube.

[0020] Optionally, the air guiding pipe is inserted into the throat of the Venturi tube in parallel with the Venturi tube.

[0021] Or,

[0022] The air inlet pipe is obliquely inserted into the throat of the Venturi tube, and the horizontal angle between the end of the air inlet pipe inserted into the throat of the Venturi tube and the Venturi tube is not greater than 30°.

[0023] Optionally, a dust removal filter screen is installed at one end of the air inlet pipe placed inside the biomass crusher.

[0024] By adopting the above technical solution, the purpose of setting the dust removal filter screen is to reduce the entry of biomass powder into the air inlet pipe when the air inlet pipe sucks air.

[0025] Optionally, a vibration motor is installed on the dust removal filter screen.

[0026] By adopting the above technical solution, the purpose of setting the vibration motor is to vibrate the dust removal filter screen, so as to clean the dust on the dust removal filter screen in time and avoid the blockage of the dust removal filter screen.

[0027] Optionally, the number of elbows of the Venturi tube is not greater than 2.

[0028] By adopting the above technical solution, minimizing the number of elbows of the Venturi tube can reduce the accumulation of dust in the air inlet pipe.

[0029] Optionally, pressure gauges are installed on the cavity near the bottom of the biomass crusher, the powder conveying pipe, the bypass branch pipe, and the end of the Venturi tube far from the bypass branch pipe; an anemometer is installed on the air inlet pipe.

[0030] By adopting the above technical solution, the pressure inside the cavity of the biomass crusher, inside the powder conveying pipe, and at the inlet and outlet of the Venturi tube can be obtained in real time through the pressure gauges, so that the first valve and the second valve can be adjusted in time to continuously form a negative pressure at the throat of the Venturi tube; the anemometer can measure the wind speed inside the air inlet pipe in real time.

[0031] Optionally, the feeding component is a positive pressure air lock.

[0032] In a second aspect, the present application provides a biomass powder making and combustion system, adopting the following technical solution:

[0033] A biomass powder making and combustion system, comprising:

[0034] The above-mentioned biomass powder making and conveying device;

[0035] A combustion furnace;

[0036] A biomass burner, installed on the combustion furnace and communicated with the end of the powder conveying pipe far from the high-pressure blower.

[0037] By adopting the above technical solution, the biomass raw material is fed into the biomass crusher from the top feed inlet, screened through the screen, and the screened biomass powder enters the powder conveying pipe through the feeding component, and is carried by the high-pressure air generated by the high-pressure blower and fed into the biomass burner for combustion; due to the large pressure loss caused by the feeding component during feeding, it is sufficient to form a negative pressure in the throat of the Venturi tube, and a flow of air towards the outlet of the Venturi tube is formed in the center of the air induction pipe, so that the air in the cavity below the biomass crusher can be continuously sucked, thereby improving the powder making efficiency; since there is no need to install an induced draft fan, the operating cost and the later maintenance cost of the powder making and conveying device are reduced.

[0038] In summary, the present application has at least the following beneficial effects:

[0039] 1. The purpose of setting the feeding component, the Venturi tube and the air induction pipe is that due to the large pressure loss caused by the feeding component during feeding, it is sufficient to form a negative pressure in the throat of the Venturi tube, and a flow of air towards the outlet of the Venturi tube is formed in the center of the air induction pipe, so that the air in the cavity below the biomass crusher can be continuously sucked, thereby improving the powder making efficiency; since there is no need to install an induced draft fan, the operating cost and the later maintenance cost of the powder making and conveying device are reduced.

[0040] 2. Since the biomass powder produced by the biomass crusher directly enters the powder conveying pipe through the air lock, there is no need to newly build a biomass storage, so there is no air volume and dust emission in the whole process, and the environmental protection performance is significantly improved.

[0041] 3. Since the biomass powder is pneumatically conveyed to the biomass burner for combustion immediately after being made by the biomass crusher, the integration of powder making, conveying and combustion is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is the overall structural schematic diagram of the biological powder making and conveying device with the air induction pipe inserted parallel into the Venturi tube of the present application;

[0043] Figure 2 is the speed and pressure distribution of the biological powder making and conveying device with the air induction pipe inserted parallel into the throat of the Venturi tube;

[0044] Figure 3 is the overall structural schematic diagram of the biological powder making and conveying device with the air induction pipe inserted obliquely into the Venturi tube in the present application;

[0045] Figure 4 is the speed and pressure distribution of the biological powder making and conveying device with the air induction pipe inserted obliquely into the throat of the Venturi tube;

[0046] Figure 5 is the overall structural schematic diagram of the biological powder making and combustion system with the air induction pipe inserted parallel into the Venturi tube of the present application;

[0047] Figure 6 This is a schematic diagram of the overall structure of a biomass powder combustion system in which the air inlet pipe of the present application is obliquely inserted into a Venturi tube.

[0048] Description of the reference numerals: 100, biomass crusher; 101, sieve; 102, positive pressure air lock; 200, powder conveying pipe; 210, second valve; 300, biomass burner; 310, ignition oil gun; 400, high-pressure blower; 500, Venturi tube; 510, bypass branch pipe; 511, first valve; 600, air inlet pipe; 601, dust removal filter screen; 602, vibration motor; 900, combustion furnace. Specific embodiments

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will combine the appended drawings in the embodiments of the present invention Figure 1 - appended drawings Figure 6 , and clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0050] An embodiment of the present application discloses a biomass powder conveying device. Referring to Figure 1 , as an embodiment of the biomass powder conveying device, the conveying device may include:

[0051] A biomass crusher 100 for crushing biomass raw materials and outputting biomass powder; wherein, the biomass raw materials may be wood chips with a length less than 20 cm.

[0052] A sieve 101 installed at the bottom of the biomass crusher 100 for filtering biomass powder;

[0053] A feeding component installed at the bottom of the biomass crusher 100 and located on the side of the sieve 101 away from the feeding port of the biomass crusher 100 for continuously and stably feeding and isolating the leakage of air from the cavity of the biomass crusher 100;

[0054] Among them, the feeding component may adopt a positive pressure air lock 102.

[0055] A powder conveying pipe 200, one end of which is connected to a biomass burner 300 for burning biomass powder, for conveying biomass powder; the feeding component is communicated with the powder conveying pipe 200, and the feeding component is also used to isolate the air flow in the powder conveying pipe 200 from flowing into the biomass crusher 100;

[0056] A high-pressure blower 400, the air outlet of which is communicated with the other end of the powder conveying pipe 200, for providing high-pressure air;

[0057] Among them, the high-pressure blower 400 can adopt a Roots blower.

[0058] The Venturi tube 500 has a bypass branch pipe 510 connected to one end. The bypass branch pipe 510 is connected to the end of the powder conveying pipe 200 close to the high-pressure blower 400, and the other end is connected to the end of the powder conveying pipe 200 far from the high-pressure blower 400.

[0059] It should be noted that the diameter of the throat section of the Venturi tube 500 can be 1 / 5 - 1 / 10 of the diameter of the inlet section of the Venturi tube 500.

[0060] The air induction pipe 600 has one end connected to the inner cavity of the biomass crusher 100, and the connection is located on the side of the screen 101 away from the feed inlet of the biomass crusher 100. The other end is inserted into the throat of the Venturi tube 500 to form a negative pressure at the throat of the Venturi tube 500.

[0061] In order to control the wind pressure and flow rate in the bypass branch pipe 510, a first valve 511 is installed on the bypass branch pipe 510. In order to control the wind pressure and flow rate in the powder conveying pipe 200, a second valve 210 is installed on the powder conveying pipe 200. The second valve 210 is located on the side of the bypass branch pipe 510 away from the high-pressure blower 400.

[0062] In addition, pressure gauges are installed on the cavity near the bottom of the biomass crusher 100, the powder conveying pipe 200, the bypass branch pipe 510, and the end of the Venturi tube 500 away from the bypass branch pipe 510 to obtain the pressure in the cavity of the biomass crusher 100, in the powder conveying pipe 200, and at the inlet and outlet of the Venturi tube 500 in real time. An anemometer is installed on the air induction pipe 600 to measure the wind speed in the air induction pipe 600 in real time.

[0063] In other embodiments, both the first valve 511 and the second valve 210 can adopt solenoid valves. The first valve 511, the second valve 210, the pressure gauge, and the anemometer can all be connected to a controller such as a PLC. The controller can be connected to a terminal, so as to automatically adjust the first valve 511 and the second valve 210 according to the values obtained from the pressure gauge and the anemometer, so that a negative pressure is continuously formed at the throat of the Venturi tube 500. Among them, the terminal can be an intelligent display device such as a computer, a smart phone, or a tablet to display the change curves of the pressure gauge and the anemometer in each time period. The time period can be set manually.

[0064] Refer to Figure 1 and Figure 2, It should be noted that, as an implementation manner of inserting the air guiding pipe 600 into the throat of the Venturi tube 500, the air guiding pipe 600 can be inserted into the throat of the Venturi tube 500 in parallel with the Venturi tube 500. At this time, the cross-sectional diameter of the throat of the Venturi tube 500 is 1 / 10 of the cross-sectional diameter of the inlet of the Venturi tube 500, the inlet pressure is 10 kPa, and when the pressure difference between the inlet and outlet is greater than 2.5 kPa, a negative pressure will appear in the throat of the Venturi tube 500.

[0065] Refer to Figure 3 and Figure 4 , as another implementation manner of inserting the air guiding pipe 600 into the throat of the Venturi tube 500, the air guiding pipe 600 can be inserted into the throat of the Venturi tube 500 obliquely, and the horizontal angle between the end of the air guiding pipe 600 inserted into the throat of the Venturi tube 500 and the Venturi tube 500 is not greater than 30°. In this application, if the oblique insertion method is adopted, the air guiding pipe 600 can be obliquely inserted into the Venturi tube 500 at an angle of 15° of the horizontal angle. The cross-sectional diameter of the throat of the Venturi tube 500 is 1 / 10 of the cross-sectional diameter of the inlet of the Venturi tube 500, the inlet pressure is 10 kPa, and when the pressure difference between the inlet and outlet of the Venturi tube 500 is greater than 6 kPa, a negative pressure will appear in the throat of the Venturi tube 500.

[0066] Refer to Figure 1 and Figure 3 , it should also be noted that when the air guiding pipe 600 sucks air, the entry of biomass powder into the air guiding pipe 600 is reduced, and a dust removal filter screen 601 is installed at one end of the air guiding pipe 600 placed inside the biomass crusher 100. Among them, the diameter of the dust removal filter screen 601 is less than 2 mm.

[0067] In order to avoid clogging of the dust removal filter screen 601, a vibration motor 602 is installed on the dust removal filter screen 601, and the vibration motor 602 is used to drive the vibration of the dust removal filter screen 601.

[0068] In order to reduce the accumulation of dust in the air guiding pipe 600, the number of elbows of the Venturi tube 500 is less than or equal to 2.

[0069] The implementation principle of this embodiment is as follows:

[0070] The biomass raw material is fed into the top feed port of the biomass crusher 100, screened by the screen 101, and the screened biomass powder enters the powder conveying pipe 200 through the positive pressure air lock 102, and is carried by the high-pressure air generated by the high-pressure blower 400 and sent into the biomass burner 300 for combustion; since the pressure loss caused by the positive pressure air lock 102 during feeding is large enough, it is sufficient to form a negative pressure in the throat of the Venturi tube 500, and a wind flowing from the center of the air guiding pipe 600 to the outlet of the Venturi tube 500 is formed, so that the air in the lower cavity of the biomass crusher 100 can be continuously sucked, thereby improving the powder making efficiency.

[0071] Another embodiment of the present application discloses a biomass pulverizing combustion system. Refer to Figure 5 and Figure 6 , as an embodiment of the combustion system, the combustion system may include:

[0072] The above-mentioned biomass pulverizing and conveying device;

[0073] Combustion furnace 900;

[0074] Biomass burner 300, installed on the combustion furnace 900 and communicated with the end of the powder conveying pipe 200 far from the high-pressure blower 400. Among them, the combustion furnace 900 may be a biomass combustion furnace 900, or a pulverized coal furnace, a pulverized coal industrial boiler, etc. The biomass burner 300 may adopt a direct current burner or a swirl burner. The biomass burner 300 is equipped with an ignition oil gun 310 for igniting the biomass powder.

[0075] The implementation principle of this embodiment is:

[0076] The material raw materials are fed into the top feed port of the biomass pulverizer 100, screened by the screen 101, and the screened biomass powder enters the powder conveying pipe 200 through the positive pressure air lock 102 and is carried by the high-pressure air generated by the high-pressure blower 400 into the biomass burner 300 for combustion. Since the pressure loss caused by the positive pressure air lock 102 during feeding is large enough, it is sufficient to form a negative pressure in the throat of the Venturi tube 500, and the air flowing towards the outlet of the Venturi tube 500 is formed in the center of the air induction pipe 600, so that the air in the cavity below the biomass pulverizer 100 can be continuously sucked, thereby improving the pulverizing efficiency.

[0077] The above are all preferred embodiments of the present application, and do not limit the protection scope of the present application in turn. Any feature disclosed in this specification (including the abstract and drawings), unless specifically described, can be replaced by other equivalent or similar-purpose alternative features. That is, unless specifically described, each feature is only an example of a series of equivalent or similar features.

Claims

1. A biomass powder-making and conveying device, characterized in that, Comprising: A biomass crusher (100) for crushing biomass raw materials and outputting biomass powder; A sieve mesh (101) installed at the bottom of the biomass crusher (100) for filtering the biomass powder; A feeding component installed at the bottom of the biomass crusher (100) and on the side of the sieve mesh (101) away from the feeding port of the biomass crusher (100) for continuous and stable feeding and isolating the leakage of air from the cavity of the biomass crusher (100); A powder conveying pipe (200) with one end connected to a biomass burner (300) for burning biomass powder for conveying biomass powder; the feeding component is communicated with the powder conveying pipe (200), and the feeding component is also used to isolate the air flow in the powder conveying pipe (200) from flowing into the cavity of the biomass crusher (100); A high-pressure blower (400) with an air outlet communicated with the other end of the powder conveying pipe (200) for providing high-pressure air; A Venturi tube (500) with one end communicated with a bypass branch pipe (510), the bypass branch pipe (510) is communicated with the end of the powder conveying pipe (200) close to the high-pressure blower (400), and the other end is communicated with the end of the powder conveying pipe (200) away from the high-pressure blower (400); An air guiding pipe (600) with one end communicated with the cavity of the biomass crusher (100), and the communicating position is on the side of the sieve mesh (101) away from the feeding port of the biomass crusher (100), and the other end is inserted into the throat of the Venturi tube (500) for forming a negative pressure at the throat of the Venturi tube (500).

2. The biomass powder-making and conveying device according to claim 1, wherein A first valve (511) is installed on the bypass branch pipe (510), and the first valve (511) is used to control the air pressure and flow rate in the bypass branch pipe (510); A second valve (210) is installed on the powder conveying pipe (200), and the second valve (210) is located on the side of the bypass branch pipe (510) away from the high-pressure blower (400); the second valve (210) is used to control the air pressure and flow rate in the powder conveying pipe (200).

3. The biomass powder-making and conveying device according to claim 2, wherein, The diameter of the cross-section of the throat of the Venturi tube (500) is 1 / 5 - 1 / 10 of the diameter of the inlet cross-section of the Venturi tube (500).

4. A biomass powder-making and conveying device according to claim 3, wherein The air guiding pipe (600) is inserted into the throat of the Venturi tube (500) in parallel with the Venturi tube (500); Or, The air guiding pipe (600) is inserted into the throat of the Venturi tube (500) obliquely, and the horizontal included angle between the end of the air guiding pipe (600) inserted into the throat of the Venturi tube (500) and the Venturi tube (500) is not greater than 30°.

5. A biomass powder-making and conveying device according to any one of claims 1-4, characterized in that, A dust removal filter screen (601) is installed at the end of the air guiding pipe (600) placed inside the biomass crusher (100).

6. The biomass powder-making and conveying device according to claim 5, wherein, A vibration motor (602) is installed on the dust removal filter screen (601).

7. A biomass powder-making and conveying device according to claim 6, characterized in that, The number of elbows of the Venturi tube (500) is not greater than 2.

8. A biomass powder-making and conveying device according to claim 1, characterized in that, Pressure gauges (700) are installed on the cavity near the bottom of the biomass crusher (100), the powder conveying pipe (200), the bypass branch pipe (510), and the end of the Venturi tube (500) far from the bypass branch pipe (510); an anemometer (800) is installed on the air induction pipe (600).

9. A biomass powder-making and conveying device according to claim 1, characterized in that, The feeding component is a positive pressure air lock (102).

10. A biomass powder-making combustion system, characterized in that, Comprising: The biomass powder making and conveying device according to any one of claims 1-9; A combustion furnace (900); A biomass burner (300) is installed on the combustion furnace (900) and is communicated with the end of the powder conveying pipe (200) far from the high-pressure blower (400).

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