Thermal decomposition device

Abstract

The invention relates to a thermal decomposition device which comprises a closed cavity, an auger shell, an auger screw, an auger speed reducer and a heater, a feeding channel and a discharging channel are arranged at the two ends of the auger shell in the length direction of the auger shell respectively, and a main body of the auger shell is located in the closed cavity; a feeding opening of the feeding channel and a discharging opening of the discharging channel extend out of the closed cavity; an auger screw is arranged in the auger shell and used for conveying materials fed into the feeding channel to the discharging channel. The extending end of the auger shell extends out of the closed cavity, and an auger speed reducer is installed at the extending end of the auger shell and connected with the auger in a spiral driving mode. The heaters serve as radiation sources to be distributed on the two sides of the packing auger shell and used for conducting radiation heating on the packing auger shell in the closed cavity, the upper half surface of the packing auger shell is coated with a heat insulation inorganic coating with the absorptivity smaller than 0.5, and the lower half surface of the packing auger shell is electroplated with an electroplating layer containing black nickel. The defect of uneven thermal decomposition temperature distribution is effectively overcome, energy consumption is reduced, and the structure is simple.

Description

Technical Field

[0001] The present invention belongs to the technical field of material thermal decomposition, and particularly relates to a thermal decomposition device. Background Art

[0002] In the existing screw conveyor pyrolysis device, the screw conveyor housing is heated by radiation heat transfer. Due to different radiation angles, the radiation intensity received by the surface of the screw conveyor housing is different, resulting in uneven heating of the outer surface of the screw conveyor. Moreover, during the operation of the screw conveyor, the filling rate is generally less than 0.5, and the heat demand is mainly concentrated in the lower half of the screw conveyor, while the heat absorbed by the upper half surface of the screw conveyor is not utilized, causing waste of heat. Summary of the Invention

[0003] Based on the above-mentioned drawbacks and deficiencies existing in the prior art, one of the objectives of the present invention is to at least solve one or more of the above problems existing in the prior art. In other words, one of the objectives of the present invention is to provide a thermal decomposition device that meets one or more of the foregoing requirements.

[0004] To achieve the above invention objective, the present invention adopts the following technical solutions:

[0005] A thermal decomposition device includes an enclosed chamber, a screw conveyor housing, a screw conveyor helix, a screw conveyor speed reducer, and a heater. The two ends of the screw conveyor housing along its length are respectively provided with a feed channel and a discharge channel. The main body of the screw conveyor housing is located inside the enclosed chamber, and the feed inlet of the feed channel and the discharge outlet of the discharge channel respectively extend outside the enclosed chamber. A screw conveyor helix is arranged inside the screw conveyor housing for conveying the feed from the feed channel to the discharge channel. The extended end of the screw conveyor housing extends outside the enclosed chamber, and a screw conveyor speed reducer is installed at the extended end of the screw conveyor housing. The screw conveyor speed reducer is drivingly connected to the screw conveyor helix. The heater is distributed on both sides of the screw conveyor housing as a radiation source for radiatively heating the screw conveyor housing inside the enclosed chamber. A heat-insulating inorganic coating with an absorptivity less than 0.5 is coated on the upper half surface of the screw conveyor housing, and an electroplated coating containing black nickel is electroplated on the lower half surface.

[0006] As a preferred solution, the lower half surface of the screw conveyor housing is axially divided into several segments, and the thicknesses of the black nickel coatings of each segment are different, so that the heat exchange heat received by each segment is within the preset engineering error range.

[0007] As a preferred solution, the heat exchange heat received by each segment is the product of the radiation amount received by each segment and the absorption-emission ratio;

[0008] Among them, the thicknesses of the black nickel coatings of each segment are different, and the corresponding absorption-emission ratios are different;

[0009] The absorption-emission ratio is the ratio of the absorptivity to the emissivity of the black nickel coating.

[0010] As a preferred solution, the radiation dose received by each segment is as follows:

[0011]

[0012] where Eb i is the radiation dose received by the i-th segment, and the radiation wavelength λ of the radiation source ∈ (0, ∞);

[0013] Taking the center of the radiation source as the origin O, the normal line of the radiation surface as the X-axis, the line parallel to the auger as the Y-axis, and the normal line of the XOY plane as the Z-axis, a coordinate system is constructed. Let the electroplated coating of the i-th segment be an arc surface enclosed by four corner points ABDC counterclockwise along the axial and circumferential directions of the auger, and are the included angles formed by AOB and COD with XOZ respectively, and θ i and θ i+1 are the included angles formed by AOC and BOD with XOY respectively. C1 and C2 are the first radiation constant and the second radiation constant respectively, and T is the temperature of the radiation source

[0014] As a preferred solution, the lower half surface of the auger housing is equally divided along its axial direction.

[0015] As a preferred solution, the radiation source is installed outside the closed chamber, and the distance between the radiation source and the auger housing is not less than one order of magnitude different from the opening diameter of the closed chamber corresponding to the radiation source.

[0016] As a preferred solution, the radius of the auger housing is not less than one order of magnitude different from the distance between the radiation source and the auger housing.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The thermal decomposition device of the present invention not only improves the problem of uneven temperature distribution on the auger housing, but also saves energy, has a simple structure, is low-carbon and environmentally friendly, is easy to operate, and is safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of the thermal decomposition device according to Embodiment 1 of the present invention;

[0020] Figure 2 is a schematic structural diagram of the thermal decomposition device according to Embodiment 1 of the present invention from another perspective;

[0021] Figure 3 is a schematic diagram of the radiation angle according to Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] To more clearly illustrate the embodiments of the present invention, the specific implementation manners of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, and other implementation manners can also be obtained.

[0023] Embodiment 1:

[0024] As Figure 1 and Figure 2 shown, the thermal decomposition device of this embodiment includes a closed chamber 1, a screw conveyor 2, and a heater 3.

[0025] Specifically, the screw conveyor 2 includes a screw housing 20, a screw spiral, and a screw reducer 4. The two ends of the screw housing along its length direction are respectively provided with a feed channel and a discharge channel. The main body of the screw housing is located inside the closed chamber 1. The feed port 5 of the feed channel and the discharge port 6 of the discharge channel respectively extend outside the closed chamber 1. A screw spiral is provided inside the screw housing for conveying the feed in the feed channel to the discharge channel. The extended end of the screw housing extends outside the closed chamber. The screw reducer 4 is installed at the extended end of the screw housing, and the screw reducer is drivingly connected to the screw spiral. The specific installation and connection relationship of the screw conveyor can refer to the prior art and will not be elaborated here.

[0026] The fly ash material enters from the feed port 5 and is output from the discharge port 6 through the screw conveyor 2. During the transportation process, the heater 3 exchanges heat with the screw housing through radiative heat transfer.

[0027] The four heaters 3 of this embodiment are distributed on the front and back sides of the screw housing as radiation sources for radiatively heating the screw housing inside the closed chamber, that is, the two heaters on the front side mainly radiatively heat the front half of the screw housing, and the two heaters on the back side mainly radiatively heat the back half of the screw housing. Among them, the radiation source 3 is installed outside the closed chamber 1, and the distance between the radiation source 3 and the screw housing 20 differs by one order of magnitude from the opening diameter 10 of the closed chamber corresponding to the radiation source, that is, the distance between the radiation source 3 and the screw housing 20 is ten times the opening diameter 10 of the closed chamber corresponding to the radiation source. The radius of the screw housing 20 differs by one order of magnitude from the distance between the radiation source 3 and the screw housing 20, that is, the radius of the screw housing 20 is ten times the distance between the radiation source 3 and the screw housing 20.

[0028] The upper half surface 201 of the screw housing of this embodiment is coated with a coating with an absorptivity less than 0.5, such as an inorganic coating composed of zirconia and rare earth substances (cerium oxide, lanthanum oxide, etc.), specifically, the product model is nano thermal insulation material JD-Y16; the lower half surface 202 has a black nickel coating; such a design can avoid heat waste on the upper half of the screw housing.

[0029] In addition, the lower half surface 202 of the auger housing in the embodiment of the present invention is axially divided into several segments, and the thicknesses of the black nickel coatings of each segment are different, so that the heat exchange heat received by each segment is approximately the same, that is, within the preset engineering error range.

[0030] Specifically, the heat exchange heat received by each segment is the product of the radiation amount received by each segment and the absorption-emission ratio; among them, the thicknesses of the black nickel coatings of each segment are different, and the corresponding absorption-emission ratios are different. The absorption-emission ratio is the ratio of the absorptivity to the emissivity of the black nickel coating.

[0031] Since different thicknesses of the black nickel coating will affect the absorption-emission ratio, the corresponding relationship can generally be obtained through experiments. The following are the absorption-emission ratios corresponding to several different thicknesses of the black nickel coating, as shown in Table 1.

[0032] Table 1 Absorption-emission ratios corresponding to different thicknesses of black nickel coatings

[0033]

[0034] In this embodiment, the upper half of the auger housing is coated with a special coating so that the absorption ratio is a relatively low value, ensuring that the upper half absorbs less radiation.

[0035] The lower half of the auger housing is equally divided into N segments, and the radiation amounts Eb1, Eb2, Eb3,..., Eb received by the surfaces of each segment are calculated respectively. N .

[0036] The radiation amount received by each segment is:

[0037]

[0038] Among them, Eb i is the radiation amount received by the i-th segment, and the radiation wavelength λ of the radiation source ∈ (0, ∞);

[0039] As Figure 3 shown, with the center of the radiation source as the origin O, the normal of the radiation surface as the X-axis, the line parallel to the auger (i.e., the axis of the auger) as the Y-axis, and the normal of the XOY plane as the Z-axis, a coordinate system is constructed; it is assumed that the electroplated coating of the i-th segment is an arc surface enclosed by four corner points ABDC counterclockwise along the axis and circumference of the auger, and this arc surface corresponds to half of the i-th segment of the lower half surface of the auger housing along its axis bisected axially. and are the included angles formed by AOB and COD with XOZ respectively, θ i and θ i+1 are the included angles formed by AOC and BOD with XOY respectively, and C1 and C2 are the first radiation constants 3.7419*10 -16 W·m 2and the second radiation constant 1.4388×10 - 2 m·K, where T is the temperature of the radiation source. As Figure 3 shown, the angular distribution of the first segment I is exemplified.

[0040] In this embodiment, by coating a special coating layer on the lower surface of the auger housing to change the surface absorption-divergence ratio, the absorption-divergence ratios of each segment in the lower half are γ1, γ2, γ3,......, γ N , and the calculated numerical values of the product of the two are E1, E2, E3,......, E N , and by adjusting the thickness of the black nickel coating layer, E1 = E2 = E3,......, = E N , thereby ensuring that the heat exchange heat received by each segment is the same, and thus ensuring the temperature uniformity of the entire lower half of the auger.

[0041] Embodiment 2:

[0042] The difference between the thermal decomposition device of this embodiment and that of Embodiment 1 is that:

[0043] The distance between the radiation source and the auger housing is more than one order of magnitude different from the opening diameter of the closed chamber corresponding to the radiation source, that is, more than 10 times; the specific dimensions can be determined according to actual requirements;

[0044] Or, the radius of the auger housing is more than one order of magnitude different from the distance between the radiation source and the auger housing, that is, more than 10 times; the specific dimensions can be determined according to actual requirements;

[0045] Other structures can refer to Embodiment 1.

[0046] The above is only a detailed description of the preferred embodiments and principles of the present invention. For those of ordinary skill in the art, according to the idea provided by the present invention, there will be changes in the specific implementation manners, and these changes should also be regarded as the protection scope of the present invention.

Claims

1. A thermal decomposition device, comprising an enclosed chamber, a screw conveyor housing, a screw conveyor helix, a screw conveyor speed reducer, and a heater. The two ends of the screw conveyor housing along its length direction are respectively provided with a feed channel and a discharge channel. The main body of the screw conveyor housing is located inside the enclosed chamber, and the feed inlet of the feed channel and the discharge outlet of the discharge channel respectively extend outside the enclosed chamber. A screw conveyor helix is arranged inside the screw conveyor housing for conveying the feed in the feed channel to the discharge channel. The extended end of the screw conveyor housing extends outside the enclosed chamber, and a screw conveyor speed reducer is installed at the extended end of the screw conveyor housing. The screw conveyor speed reducer is drivingly connected to the screw conveyor helix. The heater is distributed on both sides of the screw conveyor housing as a radiation source for radiatively heating the screw conveyor housing inside the enclosed chamber, and is characterized in that, The upper half surface of the auger housing is coated with a heat-insulating inorganic coating with an absorptivity less than 0.5, and the lower half surface is electroplated with an electroplated coating containing black nickel.

2. The thermal decomposition device according to claim 1, wherein The lower half surface of the auger housing is axially divided into several segments, and the thickness of the black nickel coating of each segment is different, so that the heat exchange heat received by each segment is within the preset engineering error range.

3. The thermal decomposition device according to claim 2, characterized in that, The heat exchange heat received by each segment is the product of the radiation received by each segment and the absorption-emission ratio; Among them, the thickness of the black nickel coating of each segment is different, and the corresponding absorption-emission ratio is different; The absorption-emission ratio is the ratio of the absorptivity to the emissivity of the black nickel coating.

4. The thermal decomposition device according to claim 3, characterized in that, The radiation received by each segment is: wherein, Eb i is the radiation amount received in the i-th segment, and the radiation wavelength λ of the radiation source ∈ (0, ∞); Taking the center of the radiation source as the origin O, the normal of the radiation surface as the X-axis, the line parallel to the auger as the Y-axis, and the normal of the XOY plane as the Z-axis, a coordinate system is constructed. Let the electroplating coating of the i-th segment be an arc surface enclosed by four corner points ABDC counterclockwise along the axial and circumferential directions of the auger. and are the angles formed by AOB and COD with XOZ respectively, θ i and θ i+1 are the angles formed by AOC and BOD with XOY respectively. C1 and C2 are the first radiation constant and the second radiation constant respectively, and T is the temperature of the radiation source.

5. The thermal decomposition device according to any one of claims 2-4, characterized in that, The lower half surface of the auger housing is equally divided into segments along its axis.

6. The thermal decomposition device according to any one of claims 1-4, characterized in that, The radiation source is installed outside the closed chamber, and the distance between the radiation source and the auger housing is not less than one order of magnitude different from the opening diameter of the closed chamber corresponding to the radiation source.

7. The thermal decomposition device according to any one of claims 1-4, characterized in that, The radius of the auger housing is not less than one order of magnitude different from the distance between the radiation source and the auger housing.

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