A clean-type electric mixer for a positive-pressure pneumatic conveying system of biomass powder

Abstract

The present invention discloses a clean electric mixer for a positive pressure pneumatic conveying system of biomass powder, which comprises a negative pressure chamber, an impeller housing, an inner pipe, a mixing chamber, a driving motor and a high-pressure air source; the bottom of the negative pressure chamber is communicated with the top opening of the impeller housing, the lower end of the inner pipe passes through the negative pressure chamber and is inserted into the impeller housing through the top opening of the impeller housing, the material outlet at the bottom of the impeller housing is communicated with the inlet of the mixing chamber, an impeller is arranged in the impeller housing, the driving motor is connected with the impeller, the high-pressure air source is communicated with the air inlet of the mixing chamber, and there is a gap between the inner pipe and the top opening of the impeller housing. This mixer can ensure the rapid and uniform mixing of biomass powder and positive pressure air flow while avoiding the occurrence of dust leakage.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass transportation, and relates to a clean electric mixer for a positive pressure pneumatic conveying system of biomass powder. Background Art

[0002] Compared with small pure biomass power plants, the direct combustion coupling of biomass with coal-fired units has advantages such as lower initial investment, higher efficiency, and making full use of the transformation and development of the original coal-fired units, so it has received more and more attention. In order to increase the proportion of renewable energy consumption and improve the proportion of green electricity, the annual operating hours of thermal power plants have dropped sharply. Therefore, the direct combustion coupling of biomass has become an important direction for the transformation of future thermal power plants.

[0003] The direct combustion coupling biomass system of coal-fired units generally includes a discharging system, a screening system, a silo storage system, a pulverizing system, a conveying and coupling system. Among them, the conveying and coupling system is responsible for transporting the qualified biomass powder produced by the pulverizing system to the furnace or in front of the furnace to achieve coupling with the coal-fired boiler. A qualified conveying system should ensure conveying capacity, continuous and stable operation, no dust leakage and pollution, matching of in-furnace combustion, and low energy consumption. When directly adopting a pneumatic conveying system similar to that of pulverized coal, the following problems exist: Biomass powder is coarser than pulverized coal, the particles are in the shape of wood chips rather than spherical, the friction coefficient is larger, and the mass ratio of air to powder is generally about 0.5. Compared with 1.5 - 2.0 for pulverized coal conveying, its solid phase concentration is higher. Using a traditional feeding structure is prone to problems such as insufficient output and blockage. Therefore, a clean electric mixer dedicated to the positive pressure pneumatic conveying system of biomass powder is needed to achieve rapid and uniform mixing of biomass powder and positive pressure air flow while avoiding dust leakage. Summary of the Invention

[0004] The purpose of the invention is to overcome the above-mentioned disadvantages of the prior art, and provide a clean electric mixer for a positive pressure pneumatic conveying system of biomass powder, which can achieve rapid and uniform mixing of biomass powder and positive pressure air flow while avoiding dust leakage.

[0005] To achieve the above purpose, the clean electric mixer for a positive pressure pneumatic conveying system of biomass powder described in the invention includes a negative pressure chamber, an impeller housing, an inner pipe, a mixing chamber, a driving motor and a high-pressure air source;

[0006] The bottom of the negative pressure chamber is connected to the top opening of the impeller housing. The lower end of the inner pipe passes through the negative pressure chamber and is inserted into the impeller housing through the top opening of the impeller housing. The material outlet at the bottom of the impeller housing is connected to the inlet of the mixing chamber. An impeller is arranged in the impeller housing. The driving motor is connected to the impeller. The high-pressure air source is connected to the air inlet of the mixing chamber. There is a gap between the inner pipe and the top opening of the impeller housing.

[0007] The mixing chamber adopts a tee structure. Among them, the first opening on the side of the mixing chamber is communicated with the outlet at the bottom of the impeller housing, the second opening at one end of the mixing chamber is communicated with a high-pressure gas source, and the third opening at the other end of the mixing chamber is communicated with a downstream equipment unit.

[0008] A cut-off partition structure is arranged on the side of the outlet of the inner pipe.

[0009] The lower side of the cut-off partition structure is located inside the impeller housing, and the upper side of the cut-off partition structure is located inside the negative pressure chamber.

[0010] It also includes a purification device, and the exhaust interface at the top of the negative pressure chamber is communicated with the purification device.

[0011] The outlet at the bottom of the impeller housing is communicated with the first opening on the mixing chamber through a feeding pipe.

[0012] The feeding pipe adopts a wide-caliber straight-through port structure.

[0013] The mixing chamber adopts a through-diameter structure.

[0014] The present invention has the following beneficial effects:

[0015] When the clean-type electric mixer for the positive-pressure pneumatic conveying system of biomass powder of the present invention is specifically operated, the biomass powder enters the impeller housing through the inner pipe and enters the mixing chamber under the action of the impeller. High-pressure gas is introduced into the mixing chamber through a high-pressure gas source. Under the action of the high-pressure gas, the mixing of the biomass powder is realized. Among them, the high-pressure gas in the mixing chamber enters the negative pressure chamber through the gap between the inner pipe and the impeller housing, avoiding the accumulation of high-pressure gas at the outlet of the inner pipe and eliminating the hidden danger of poor powder falling and blockage caused by the pulsed impact on the falling biomass powder flow. Therefore, while ensuring the rapid and uniform mixing of the biomass powder and the positive-pressure air flow, the occurrence of dust leakage is avoided. Description of the Drawings

[0016] Figure 1 It is a structural schematic diagram of the present invention.

[0017] Among them, 1 is the inner pipe, 2 is the negative pressure chamber, 3 is the exhaust interface, 4 is the impeller housing, 5 is the impeller, and 6 is the mixing chamber. Detailed Embodiments

[0018] To enable those skilled in the art to better understand the solution of the present invention, the following will clearly and completely describe the technical solution in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present invention disclosed. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessarily confusing the concepts disclosed in the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0019] The schematic structural diagrams according to the disclosed embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are only exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0020] Referring to Figure 1 , the clean-type electric mixer for the positive-pressure pneumatic conveying system of biomass powder according to the present invention includes an inner pipe 1, a negative-pressure chamber 2, an exhaust interface 3, an impeller housing 4, an impeller 5, and a mixing chamber 6;

[0021] The bottom of the negative-pressure chamber 2 is connected to the top opening of the impeller housing 4. The lower end of the inner pipe 1 passes through the negative-pressure chamber 2 and is inserted into the impeller housing 4 through the top opening of the impeller housing 4. The material outlet at the bottom of the impeller housing 4 is connected to the inlet of the mixing chamber 6. An impeller 5 is provided in the impeller housing 4, and a driving motor is connected to the impeller 5. The impeller 5 is driven by the driving motor to rotate at a constant speed, and the biomass powder is evenly fed into the mixing chamber 6. The mixing chamber 6 is connected to a high-pressure air source.

[0022] The mixing chamber 6 adopts a tee structure. Among them, the first opening on the side of the mixing chamber 6 is connected to the outlet at the bottom of the impeller housing 4. The second opening at one end of the mixing chamber 6 is connected to the high-pressure air source. The third opening at the other end of the mixing chamber 6 is connected to the downstream equipment unit. During operation, the biomass powder and the high-pressure air flow are fully mixed in the mixing chamber 6 to form a two-phase flow, and then are discharged from the third opening on the mixing chamber 6 to the downstream equipment unit.

[0023] A notch partition structure is provided on the side of the outlet of the inner pipe 1. The lower side of the notch partition structure is located inside the impeller housing 4, and the upper side of the notch partition structure is located inside the negative pressure chamber 2. The exhaust interface 3 at the top of the negative pressure chamber 2 is connected to a purification device. The bottom outlet of the impeller housing 4 is connected to the first opening on the mixing chamber 6 through a feeding pipe. The feeding pipe adopts a wide-caliber straight-through port structure, and the mixing chamber 6 adopts a through-diameter structure.

[0024] It should be noted that the present invention has the following characteristics:

[0025] Reference Figure 1 , the impeller 5 rotates counterclockwise. Driven by the impeller 5, when the biomass powder falls into the mixing chamber 6 from the left side of the lower outlet of the impeller housing 4, the high-pressure gas in the mixing chamber 6 will reverse flow upward from the right side of the lower outlet of the impeller housing 4. The notch partition structure on the right side of the outlet of the inner pipe 1 is used to increase the throat flow area for the reverse-flowing air to enter the negative pressure chamber 2, prevent it from accumulating at the outlet of the inner pipe 1, and eliminate the hidden danger of causing poor powder feeding and blockage due to the pulsed impact on the falling biomass powder flow.

[0026] The exhaust interface 3 at the top of the negative pressure chamber 2 is connected to a purification device. With the continuous suction of the purification device, a negative pressure environment is maintained inside the negative pressure chamber 2 at all times to ensure that the high-pressure reverse-flowing air will not flow further to the upper-level processing unit, and prevent dust leakage at the equipment connection of the upper-level processing unit.

[0027] After the high-pressure reverse-flowing air enters the negative pressure chamber 2, it will quickly spread and depressurize. At the same time, the large particles of the blown-up biomass powder will naturally settle and return to the impeller housing 4 due to gravity, while the small particles will go to the purification device through the exhaust interface 3 with the air flow to complete gas-solid separation. The separated biomass powder will return to the upper-level processing unit, and the purified gas will be discharged.

[0028] Biomass powder is coarser than coal powder, the particles are in the shape of wood chips rather than spherical, the friction coefficient is larger, and the air-powder mass ratio is generally about 0.5. Compared with 1.5 - 2.0 for coal powder transportation, its solid-phase concentration is higher. Using a traditional feeding structure is prone to problems such as insufficient output and blockage. Therefore, the structure of the mixing chamber 6 has the following characteristics compared with the traditional coal powder mixing chamber: a) The feeding pipe adopts a wide-caliber straight-through port design, different from the flared port of the coal powder mixing chamber, which can ensure a large amount of biomass powder enters the main cavity quickly; b) The main cavity adopts a through-diameter design, canceling the common reduced-diameter and partition plate designs of the coal powder mixing chamber, increasing the accommodation capacity of the main cavity, and preventing a large amount of biomass powder from blocking at the main cavity.

[0029] In summary, the present invention can ensure the rapid and uniform mixing of biomass powder and high-pressure air flow while avoiding dust leakage. Moreover, the present invention fully considers the physical characteristics, conveying characteristics, and resistance characteristics of biomass powder, and while ensuring the conveying output of biomass powder, there is no dust emission pollution or local blockage and deflagration, thereby realizing the safe, civilized, and stable operation of the system.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. A clean electric mixer for a positive pressure pneumatic conveying system of biomass powder, characterized in that, It includes a negative pressure chamber (2), an impeller housing (4), an inner pipe (1), a mixing chamber (6), a driving motor and a high-pressure gas source; The bottom of the negative pressure chamber (2) is communicated with the top opening of the impeller housing (4). The lower end of the inner pipe (1) passes through the negative pressure chamber (2) and is inserted into the impeller housing (4) through the top opening of the impeller housing (4). The material outlet at the bottom of the impeller housing (4) is communicated with the inlet of the mixing chamber (6). An impeller (5) is arranged in the impeller housing (4). The driving motor is connected to the impeller (5). The high-pressure gas source is communicated with the air inlet of the mixing chamber (6). There is a gap between the inner pipe (1) and the top opening of the impeller housing (4); A cut-off partition structure is arranged on the side of the outlet of the inner pipe (1); The lower side of the cut-off partition structure is located in the impeller housing (4), and the upper side of the cut-off partition structure is located in the negative pressure chamber (2); It further includes a purification device. The exhaust interface (3) at the top of the negative pressure chamber (2) is communicated with the purification device; During operation, the impeller (5) rotates counterclockwise. Driven by the impeller (5), while the biomass powder falls into the mixing chamber (6) from the left side of the lower outlet of the impeller housing (4), the high-pressure gas in the mixing chamber (6) rushes upward from the right side of the lower outlet of the impeller housing (4). The cut-off partition structure on the right side of the outlet of the inner pipe (1) increases the throat flow area for the upward-rushing air flow to enter the negative pressure chamber (2), avoiding its accumulation at the outlet of the inner pipe (1), and eliminating the hidden danger of causing poor powder feeding and blockage due to the pulsed impact on the falling biomass powder flow; The mixing chamber (6) adopts a tee structure. Among them, the first opening on the side of the mixing chamber (6) is communicated with the outlet at the bottom of the impeller housing (4), the second opening at one end of the mixing chamber (6) is connected to the high-pressure gas source, and the third opening at the other end of the mixing chamber (6) is connected to the downstream equipment unit; The bottom outlet of the impeller housing (4) is connected to the first opening on the mixing chamber (6) through a feeding pipe; The feeding pipe adopts a wide-caliber straight-through opening structure; The mixing chamber (6) adopts a through-diameter structure.

Images