A rotary kiln gas collecting pipe and a pyrolysis rotary kiln device

Abstract

The present invention provides a rotary kiln gas collecting pipe and a pyrolysis rotary kiln device, which relates to the technical field of pyrolysis. It includes a stepped central pipe and a sizing central pipe. One end of the stepped central pipe is communicated with the sizing central pipe, and a plurality of air inlets are arranged on the outer peripheral wall of the stepped central pipe. A gas inlet is arranged on the outer wall of the stepped central pipe, so that the tar-containing gas pyrolyzed from the material can enter the rotary kiln gas collecting pipe in time. Such a setting is beneficial for the low-temperature gas not to pass through the high-temperature pyrolysis temperature section, thereby avoiding the secondary cracking or condensation of light coal tar, increasing the yield of coal tar and obtaining coal tar with a smaller density. At the same time, the economic benefits are also greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pyrolysis, and in particular, to a rotary kiln gas collecting pipe and a pyrolysis rotary kiln device. Background Art

[0002] Generally, the pyrolysis of coal and biomass is carried out in a horizontal rotary kiln. No matter where the gas is generated in the horizontal rotary kiln, it converges to the discharge port of the rotary kiln and is then discharged from the kiln body through the gas outlet of the discharge hood. In the pyrolysis kiln, the temperature at the feeding port is usually the lowest during the heating and pyrolysis process of coal, and the highest temperature zone is close to the discharge port. However, the starting temperature of coal pyrolysis is about 350 - 360 °C, and the outlet temperature of the pyrolysis kiln is different according to the different solid products of pyrolysis. Among them, the outlet temperature of semi-coke is about 650 °C, and the outlet temperature of coke is above 900 °C. Currently, the coal pyrolysis gas has to pass through the highest temperature of pyrolysis before reaching the gas outlet, resulting in the defect of low output of low-temperature coal tar.

[0003] In view of this, the present invention is specifically proposed. Summary of the Invention

[0004] The purpose of the present invention is to provide a rotary kiln gas collecting pipe and a pyrolysis rotary kiln device to solve the above technical problems.

[0005] The present invention is implemented as follows:

[0006] A rotary kiln gas collecting pipe includes a stepped central pipe and a sizing central pipe. One end of the stepped central pipe is communicated with the sizing central pipe, and a plurality of air inlets are arranged on the outer peripheral wall of the stepped central pipe.

[0007] The inventor found that the coal tar produced at low temperature will be secondarily cracked and condensed when passing through the subsequent high-temperature section, greatly reducing the yield of light oil. Part of it is cracked into small molecules such as H2, CO, and CO2, and part of it is polymerized into asphaltene or gum or even coking products, significantly reducing the high-value low-temperature coal tar, which is not conducive to maximizing economic benefits.

[0008] The pyrolysis temperature of coal is about 360 °C. The starting point of the stepped central pipe is calculated as 360 °C ± 50 °C, and the highest temperature of pyrolysis varies according to different pyrolysis products. However, generally, the coal pyrolysis in a rotary kiln is medium-low temperature pyrolysis, and the highest temperature of pyrolysis is within 450 - 650 °C. The closer the highest temperature is to 450 °C, the higher the yield of coal tar, and the higher the proportion of coal tar with a density less than 1, and the higher the economic value obtained from the coal tar; the closer the highest temperature is to 650 °C, the yield of coal tar decreases, and the higher the proportion of coal tar with a density greater than 1, but the volatile matter of the coal after pyrolysis is lower and the gas volume increases.

[0009] In view of this, a rotary kiln gas collecting pipe is provided. This rotary kiln gas collecting pipe aims to prevent the light coal tar generated during the pyrolysis process from undergoing secondary cracking and polycondensation as much as possible, thereby maximizing the proportion of low-temperature coal tar and maximizing the yield of coal tar.

[0010] The outer peripheral wall of the stepped central pipe is provided with air inlets, enabling the tar-containing gas pyrolyzed from the material to enter the rotary kiln gas collecting pipe in a timely manner. This allows the low-temperature gas to bypass the high-temperature pyrolysis section, thereby avoiding the occurrence of secondary cracking or polycondensation of light coal tar, which is beneficial to increasing the yield of coal tar and obtaining coal tar with a smaller density. Inside the stepped central pipe, the coal tar generated during the low-temperature pyrolysis of coal has a smaller density, and the yield of low-temperature coal tar is relatively high, reaching more than 10%, resulting in better economic benefits.

[0011] It should be noted that the above stepped central pipe can be a central pipe with a gradually changing diameter along the feeding direction or a central pipe with a constant diameter. For example, the diameter of the stepped central pipe is the same as that of the constant-diameter central pipe. The above stepped central pipe is not limited to the case of a gradually changing diameter.

[0012] In a preferred embodiment of the application of the present invention, the diameter of the end of the stepped central pipe close to the constant-diameter central pipe is larger than that of the end far from the constant-diameter central pipe, and the diameter of the stepped central pipe changes gradually along the feeding direction.

[0013] A clamping pipe is provided at the end of the stepped central pipe close to the constant-diameter central pipe. The inner diameter of the clamping pipe is 1 - 5 mm larger than the outer diameter of the constant-diameter central pipe. The end of the clamping pipe close to the stepped central pipe extends 50 - 100 mm beyond the constant-diameter central pipe, and the end of the clamping pipe far from the stepped central pipe is fixedly connected to the constant-diameter central pipe;

[0014] A plurality of guiding inserts are evenly distributed along the circumferential direction on the outer wall surface of the end of the stepped central pipe close to the constant-diameter central pipe. Each guiding insert is stepped in the radial direction. The end with a smaller area of the guiding insert is located at the end of the stepped central pipe, and the end with a larger area of the guiding insert is fixedly welded to the outer wall of the stepped central pipe vertically. There is a gap between the end with a smaller area of the guiding insert and the clamping pipe. The clamping pipe is inserted into the stepped central pipe through the guiding of the guiding insert, connecting the stepped central pipe and the constant-diameter central pipe.

[0015] In addition, in other embodiments, the positions of the above clamping pipe and guiding insert can be interchanged, that is, the positions of the clamping pipe and the guiding insert are swapped.

[0016] The stepped central pipe with a gradually changing diameter along the feeding direction, and the diameter close to the constant-diameter central pipe is larger. Such a setting is beneficial for the end of the stepped central pipe that enriches more gas to meet the larger air intake flow demand, while the diameter of the end far from the constant-diameter central pipe can be set smaller according to the need because less pyrolysis gas is generated in the initial stage.

[0017] In other embodiments, a stepped central tube having the same pipe diameter as the sizing central tube may be provided.

[0018] The stepped central tube is formed by fixedly connecting a plurality of small stepped tubes through a first vertical ring, and air inlets are formed on the outer peripheral walls of each small stepped tube. A plurality of first ventilation holes are uniformly arranged on the first vertical ring. Preferably, the plurality of stepped small tubes are welded together in sequence.

[0019] Preferably, each stepped small tube is provided with a gas collection hood and a gas ventilation chamber. Except for the first stepped small tube with the smallest outer diameter, the gas collection hoods of the remaining stepped small tubes are arranged at the rear ends of the previous stepped small tubes, and the gas ventilation chambers are arranged at the ends of the current stepped small tubes close to the air inlets. One end of the gas collection hood communicates with the outside, and the other end of the gas collection hood communicates with the gas ventilation chamber through a plurality of first ventilation holes. The gas ventilation chamber is fixed on the outer periphery of the stepped small tube, and the gas ventilation chamber communicates with the inside of the stepped small tube through the air inlet.

[0020] During use, the gas generated by the pyrolysis of the material enters the ventilation chamber from the gas collection hood, enters the stepped small tube through the air inlet, and then is output through the sizing central tube and escapes from the gas outlet of the kiln tail hood.

[0021] Furthermore, in one embodiment, except for the first stepped small tube with the smallest pipe diameter, a plurality of air inlets are arranged on the pipe walls of the remaining stepped small tubes. Preferably, the air inlets are symmetric air inlets.

[0022] In other embodiments, the gas collection hood and the gas ventilation chamber can be deleted as needed, and only the stepped central tube with air inlets is retained.

[0023] Preferably, the air inlets are symmetrically arranged on the pipe wall of the stepped central tube. The so-called symmetric arrangement includes being evenly and symmetrically distributed on the pipe wall of the stepped central tube. Such an arrangement is conducive to the gas generated by the pyrolysis of the material entering the stepped central tube in a timely manner.

[0024] It should be noted that the front end (i.e., the leftmost end along the feeding direction) of the first stepped small tube can be closed, an unclosed pipeline, or semi-closed.

[0025] The preferred solution is: a third vertical ring is arranged in the inner hole of the front end of the first stepped small tube of the multi-step tube. The outer diameter of the third vertical ring is 1-3 mm smaller than the inner diameter of the first stepped small tube. The outer wall of the third vertical ring is fixed to the first stepped small tube, and the gas collection hood and the gas ventilation chamber of this level are arranged behind the third vertical ring.

[0026] Arranging a third vertical ring in the inner hole of the front end of the first stepped small tube is beneficial for blocking the material from entering the central tube, and at the same time, a part of the gas can enter through the ring holes.

[0027] In a preferred embodiment of the application of the present invention, for the first cylinder and the first vertical ring of the gas collection hood, the first cylinder is arranged at the end of the stepped small tube of the previous stage of the stepped small tube of this stage. The outer diameter of the first vertical ring is 0.5 - 3 mm smaller than the inner wall of the first cylinder, and the inner diameter of the first vertical ring is 0.5 - 3 mm larger than the outer diameter of the stepped small tube of the previous stage of this stage. Moreover, the inner peripheral wall of the first cylinder is fixedly connected to the outer wall of the stepped small tube of the previous stage through the first vertical ring, and the outer wall of the first vertical ring is fixedly connected to the inner wall of the first cylinder.

[0028] In a preferred embodiment of the application of the present invention, the above-mentioned first cylinder has a cavity, and a spiral blade is arranged in the cavity.

[0029] The spiral direction of the spiral blade has the function of pushing the larger dust particles entering the spiral blade in the opposite direction when rotating with the kiln, that is, pushing the dust entering the spiral blade along the direction opposite to the movement of the materials in the rotary kiln.

[0030] In a preferred embodiment of the application of the present invention, the above-mentioned gas ventilation chamber includes a second cylinder and a second vertical ring. The outer diameter of the second cylinder on the same stepped small tube is smaller than the outer diameter of the first cylinder, and the inner diameter of the second cylinder is larger than the outer diameter of the same stepped small tube. The second vertical ring is located on the same stepped small tube, and the ratio of the distance from the second vertical ring to the front end of the same stepped small tube to the total length of the same stepped small tube is greater than 1 / 2 (that is, the second vertical ring is located in the second half of the same stepped small tube). The outer diameter of the second vertical ring is smaller than the inner diameter of the second cylinder, and the inner diameter of the second vertical ring is larger than the outer diameter of the same stepped small tube. One end of the second cylinder is fixedly connected to the outer wall of the stepped small tube of this stage through the inner wall, the other end of the second cylinder is fixedly connected to the side wall of the first vertical ring, the outer peripheral wall of the second vertical ring is fixedly connected to the inner peripheral wall of the second cylinder, and a first ventilation hole is uniformly arranged on the first vertical ring between the first cylinder and the second cylinder.

[0031] In a preferred embodiment of the application of the present invention, the pipe diameter of the above-mentioned stepped center pipe is the same as that of the sizing center pipe.

[0032] A pyrolysis kiln rotary kiln device includes a kiln body and a rotary kiln gas collecting pipe. A plurality of pipe supports are arranged on the outer wall of the rotary kiln gas collecting pipe, and the plurality of pipe supports are fixedly connected to the inner liner of the kiln body through a center pipe support. Each pipe support corresponds to a row of center pipe supports, and each row of center pipe supports is provided with 3 - 6 center pipe sub-supports.

[0033] The pyrolysis kiln rotary kiln equipment further includes a feeding hood. A gas outlet is arranged at the top end of the feeding hood, and a pyrolyzed coal outlet is arranged at the bottom end of the feeding hood. One end of the sizing center pipe away from the stepped center pipe extends 500 - 1000 mm beyond the discharging end of the rotary kiln to reach the position of the feeding hood. The space of the minimum diameter end of the stepped center pipe is located at the position where the pyrolysis of the pyrolysis kiln starts to occur.

[0034] Preferably, the stepped center pipe is arranged from the starting pyrolysis position to the highest pyrolysis temperature position, and the pipe diameter gradually increases along the feeding direction, and the pipe diameter is the largest at the highest temperature position.

[0035] In a preferred embodiment of the application of the present invention, each of the above-mentioned pipe supports includes 2 - 6 pipe support legs and 1 pipe support surface. One end of the pipe support leg is fixedly connected to the pipe support surface. Among them, the pipe support surface is an annular surface composed of a ring, and the pipe support leg is composed of two side rings fixedly supported on both sides of the ring or is fixedly supported by 3 - 6 support webs. The other end of the pipe support leg is fixedly connected to the outer arc surface of the rotary kiln gas collecting pipe. The center pipe support includes a support leg and a support surface. One end of the support leg away from the support surface is fixedly connected to the inner liner of the kiln body, and the other end of the support leg is fixedly connected to the support surface. A plurality of first bolt through holes are arranged on the support surface, and second bolt through holes corresponding to the first bolt through holes are arranged on the pipe support surface. A gap is arranged between the pipe support surface and the support surface in the radial direction;

[0036] On the stepped center pipe and the sizing center pipe, at least one row of the first bolt through holes and the second bolt through holes on the pipe support surface and the support surface are all round holes; arranging at least one row of round holes enables the rotary kiln gas collecting pipe to have a certain axial positioning.

[0037] On the stepped center pipe and the sizing center pipe, at least one row of the first bolt through holes and the second bolt through holes on the pipe support surface and the support surface are all long holes. Arranging at least one row of long holes enables the center pipe support and the center pipe to adopt a clearance support and can slide along the axial direction. Preferably, the long holes of the first bolt through holes along the axial direction are used to eliminate stress.

[0038] In addition, in other embodiments, the shapes of the above-mentioned first bolt through holes and second bolt through holes can be adaptively adjusted according to needs, and are not limited to the shapes cited in this application.

[0039] During installation, the pipe support surface and the support surface are adjusted by wedge iron to make the rotary kiln gas collecting pipe in the center position of the kiln. Then, the first bolt through holes and the second bolt through holes are connected by bolts, and a radial clearance for thermal expansion and contraction is left between the bolt fixed head and the two locking nuts. Finally, the wedge iron is removed. After removing the wedge iron, the rotary kiln gas collecting pipe will have a situation of central downward movement, and rolling eccentricity will occur during rotation, but within a limited range. The clearance support between the center pipe support and the rotary kiln gas collecting pipe is to meet the thermal expansion and contraction between the center pipe support and the rotary kiln gas collecting pipe and eliminate the stress damage effect that may be brought by thermal expansion and contraction.

[0040] The material of the rotary kiln gas collecting pipe is stainless steel, and the material of the central pipe support is heat-resistant steel or stainless steel. Such materials can ensure the strength of the rotary kiln gas collecting pipe and its support in a high-temperature environment.

[0041] The outer diameters of the gas collecting covers of the multi-stage stepped small pipes of the stepped central pipe are all kept the same. Such a setting is to facilitate reducing the specifications of materials.

[0042] Preferably, the dimensions of the legs of the central pipe support are the same at all heights. Such a setting is to achieve unified processing and avoid mess.

[0043] A pyrolysis rotary kiln device includes the above-mentioned pyrolysis kiln.

[0044] Compared with the prior art, the beneficial effects of the present invention are:

[0045] The present invention sets a rotary kiln gas collecting pipe in the rotary kiln and sets a gas inlet on the outer wall of the stepped central pipe, so that the tar-containing gas pyrolyzed from the material can enter the rotary kiln gas collecting pipe in time. Such a setting is beneficial for the low-temperature gas not to pass through the high-temperature pyrolysis temperature section, thereby avoiding the generation of secondary cracking or polycondensation of light coal tar, increasing the yield of coal tar and obtaining coal tar with a smaller density, and also greatly improving the economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, so they should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0047] Figure 1 It is a schematic diagram of the overall layout of the coal pyrolysis rotary kiln and the central pipe (the feeding cover is not drawn);

[0048] Figure 2 It is a schematic diagram of the central pipe provided with a gas collecting cover in Embodiment 1;

[0049] Figure 3 It is a schematic diagram of the central pipe without a gas collecting cover in Embodiment 2.

[0050] Icons: 1 - Rotary kiln body; 2 - Hot air hood; 3 - Heating pipe; 4 - Pulverized coal feed end; 5 - Pyrolysis solid material discharge end; 6 - Rotary kiln gas collecting pipe; 61 - Step center pipe; 62 - Sizing center pipe; 63 - Clamping pipe; 64 - Guide plate; 65 - First gap; 66 - Symmetrical air inlet; 67 - Gas collection hood; 671 - First cylinder; 672 - First vertical ring; 673 - Spiral blade; 68 - Gas ventilation chamber; 681 - Second cylinder; 682 - Second vertical ring; 683 - First air inlet hole; 684 - Second air inlet hole; 69 - Pipe support; 691 - Pipe support leg; 692 - Pipe support surface; 693 - Second bolt through hole; 7 - Center pipe support; 71 - Leg; 72 - Support surface; 73 - First bolt through hole; 74 - Second gap; 75 - Bolt; 8 - Fixed support; 9 - Movable support; 10 - Third vertical ring. Detailed implementation manners

[0051] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. The components of the embodiments of the present invention usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0052] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0053] It should be noted that: Similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0054] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and cannot be construed as indicating or implying relative importance.

[0055] In addition, terms such as "horizontal", "vertical", "hanging", etc. do not mean that the components are required to be absolutely horizontal or hanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0056] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] Embodiment 1

[0058] Please refer to Figure 1 and Figure 2 This embodiment provides a rotary kiln for pulverized coal pyrolysis, which includes a rotary kiln body 1, a hot air hood 2 arranged on the outer periphery of the rotary kiln body 1, a plurality of uniformly distributed heating tubes 3 arranged parallel to the inner wall of the kiln, and a rotary kiln gas collecting pipe 6. Among them, the air inlet of the heating tube 3 penetrates through the rotary kiln body 1 and communicates with the hot air hood 2.

[0059] The front end of the rotary kiln body 1 is the pulverized coal feeding end 4, and the rear end is the pyrolyzed solid material discharging end 5. Pulverized coal enters the rotary kiln body 1 from the pulverized coal feeding end 4, and the remaining solid material after pyrolysis exits the rotary kiln body 1 from the pyrolyzed solid material discharging end 5. The gas generated by pyrolysis enters the rotary kiln gas collecting pipe 6 in time, and the heating tube 3 provides the temperature required for pyrolysis.

[0060] Referring to Figure 1 As shown, the rotary kiln gas collecting pipe 6 is distributed from the position where the material in the rotary kiln starts to pyrolyze to 500 - 1000 mm at the discharging end of the rotary kiln and escapes from the gas outlet of the kiln tail hood. The feeding hood is at the discharging end (not shown in the figure). Among them, the central pipe of the rotary kiln gas collecting pipe 6 from the starting position to the highest pyrolysis temperature is composed of multi-stage stepped diameter pipe sections, and the diameter gradually increases from small to large, and becomes the largest at the highest temperature. This section of the central pipe is called the stepped central pipe 61, and then the diameter remains the largest until the gas outlet end. This section of the central pipe is called the constant diameter central pipe 62.

[0061] In other embodiments, the above-mentioned stepped central pipe 61 can also be a non-variable diameter central pipe with the same diameter as the constant diameter central pipe.

[0062] Referring to Figure 2As shown, the diameter of the stepped central pipe 61 at the end close to the sizing central pipe 62 is larger than that at the end far from the sizing central pipe 62, and the diameter of the stepped central pipe 61 varies in a gradient along the feeding direction.

[0063] A clamping pipe 63 is provided at the end of the stepped central pipe 61 close to the sizing central pipe 62. The inner diameter of the clamping pipe 63 is 1 - 5 mm larger than the outer diameter of the sizing pipe 62. One end of the clamping pipe 63 extends 50 - 100 mm out of the sizing pipe, and the other end of the clamping pipe 63 is fixedly connected to the sizing central pipe 62.

[0064] On the outer wall surface of the stepped central pipe 61 at the end close to the sizing pipe 62, a plurality of guiding insertion plates 64 are evenly distributed along the circumferential direction. The guiding insertion plates 64 are stepped in the radial vertical plane. The end with a smaller area of the guiding insertion plate 64 is located at the end of the largest stepped central pipe 61. The end with a larger area of the guiding insertion plate 64 is fixedly welded to the outer wall of the stepped central pipe 61 vertically. And there is a first gap 65 between the end with a smaller area of the guiding insertion plate 64 and the clamping pipe 63 to provide guiding and telescopic movement. The clamping pipe 63 is inserted into the largest stepped central pipe 61 through the guiding of the guiding insertion plate 64, and the stepped central pipe 61 and the sizing central pipe 62 are connected.

[0065] The positions of the clamping pipe 63 and the guiding insertion plate 64 can be interchanged.

[0066] A gas collection hood 67 and a gas ventilation chamber 68 are provided for each stepped central pipe 61. Except for the first stepped central pipe 61 with the smallest outer diameter, the gas collection hoods 67 of the other stepped small pipes are arranged at the rear end of the previous stepped central pipe 61, while the gas ventilation chamber 68 is arranged at the end of the current stepped central pipe 61 close to the air inlet. One end of the gas collection hood 67 is communicated with the outside, and the other end of the gas collection hood 67 is communicated with the gas ventilation chamber 68 through a plurality of first air inlet holes 683. The gas ventilation chamber 68 is fixed on the outer periphery of the stepped small pipe, and the gas ventilation chamber 68 is communicated with the inside of the stepped small pipe through a symmetric air inlet 66.

[0067] The gas collection hood 67 includes a first cylinder 671 and a first vertical ring 672. The first cylinder 671 is arranged at the end of the stepped central pipe 61 of the previous stage of the current stepped small pipe. The first vertical ring 672 is arranged at the end of the stepped central pipe 61 of the previous stage of the current stepped small pipe. The outer diameter of the first vertical ring 672 is 0.5 - 3 mm smaller than the inner wall of the first cylinder 671, and the inner diameter of the first vertical ring 672 is 0.5 - 3 mm larger than the outer diameter of the stepped central pipe 61 of the previous stage of the current stepped small pipe. And the inner peripheral wall of the first cylinder 671 is fixedly connected to the outer wall of the stepped central pipe 61 of the previous stage through the first vertical ring 672, and the outer wall of the first vertical ring 672 is fixedly connected to the inner wall of the first cylinder 671.

[0068] In this embodiment, a corresponding gas collection hood 67 and a gas vent chamber 68 are provided in the central pipe 61 of each step. In other embodiments, the gas collection hood 67 and the gas vent chamber 68 can also be removed as needed.

[0069] On the inner wall of the first cylinder 671, a spiral blade 673 is welded. The spiral direction of the spiral blade 673 is such that when rotating with the kiln, the larger dust particles entering the spiral blade are pushed out of the spiral blade in the reverse direction. That is: the dust entering the spiral blade is pushed out in the direction opposite to the movement of the materials in the rotary kiln.

[0070] In this embodiment, the outer diameters of the gas collection hoods 67 of the central pipes 61 of each step are the same, so as to facilitate reducing the material specifications.

[0071] The gas vent chamber 68 includes a second vertical ring 682 and a second cylinder 681 with an outer diameter larger than the outer diameter of the central pipe of this section. The outer diameter of the second cylinder 681 is smaller than the diameter of the first cylinder 671. The front end of the second cylinder 681 is concentrically welded to the first vertical ring 672. The outer diameter of the second vertical ring 682 is 0.5 - 3 mm smaller than the inner diameter of the second cylinder 681, and the inner diameter of the second vertical ring 682 is 0.5 - 3 mm larger than the outer diameter of the central pipe 61 of this step.

[0072] On the first vertical ring 672, a plurality of first gas inlet holes 683 are provided, and the first gas inlet holes 683 communicate the gas collection hood 67 and the gas vent chamber 68.

[0073] On the wall of the central pipe 61 of this step, a plurality of second gas inlet holes 684 are provided.

[0074] Outside the rotary kiln gas collector pipe 6, there are 5 pipe supports 69. Corresponding to the pipe supports, there are 5 rows of central pipe brackets 7, and the number of central pipe brackets 7 (i.e., central pipe sub - brackets) arranged in each row is 4.

[0075] The pipe support 69 includes 4 pipe support legs 691 and 1 pipe support surface 692. One end of the pipe support leg 691 is welded to the rotary kiln gas collector pipe 6 along an arc, and the other end of the pipe support leg 691 is fixedly connected to the pipe support surface 692.

[0076] The central pipe bracket 7 includes a leg 71 and a support surface 72. One end of the leg 71 is welded to the inner liner of the rotary kiln body 1, and the other end of the leg 71 is welded to the support surface 72. On the support surface 72, a plurality of uniformly distributed first bolt through - holes 73 are provided.

[0077] On the pipe support surface 692, there are second bolt through - holes 693 corresponding to the first bolt through - holes 73, and the first bolt through - holes 73 and the second bolt through - holes 693 are connected by bolts 75.

[0078] Each pipe support surface 692 corresponds to 4 support surfaces 72, and correspondingly, 4 rows of corresponding second bolt through-holes 693 are provided on each pipe support surface 692.

[0079] On the stepped center pipe and the sizing center pipe, a second gap 74 is provided radially between the pipe support surface 692 and the support surface 72. The pipe support surface 692 and the support surface 72 are adjusted by wedge blocks to make the rotary kiln gas collecting pipe 6 in the center position of the kiln. Then, the first bolt through-hole 73 and the second bolt through-hole 693 are connected by bolts 75. A radial clearance for thermal expansion and contraction is left between the fixed head of the bolt 75 and the two locking nuts. Finally, the wedge blocks are removed. After the wedge blocks are removed, the rotary kiln gas collecting pipe 6 will move downward at the center, and rolling eccentricity will occur during rotation, but within a limited range.

[0080] The gap support between the center pipe support 7 and the rotary kiln gas collecting pipe 6 is used to meet the thermal expansion and contraction between the center pipe support 7 and the rotary kiln gas collecting pipe 6, and eliminate the possible stress damage caused by thermal expansion and contraction. In this embodiment, the height dimensions of the legs 71 are set to be the same for unified processing and to avoid mess.

[0081] In this embodiment, referring to Figure 2 As shown, a pair of fixed supports 8 are respectively provided on the outer peripheries of the stepped center pipe 61 and the sizing center pipe 62. The first bolt through-holes 73 on the fixed supports 8 and the second bolt through-holes 693 are circular holes in shape along the axial direction.

[0082] In this embodiment, two rows and one row of movable supports 9 are respectively provided on the outer peripheries of the stepped center pipe 61 and the sizing center pipe 62. The first bolt through-holes 73 on the movable supports 9 and the second bolt through-holes 693 are oblong holes in shape along the axial direction.

[0083] The setting of the oblong holes enables the center pipe support 7 and the rotary kiln gas collecting pipe 6 to slide axially to eliminate the stress caused by thermal expansion and contraction.

[0084] The material of the rotary kiln gas collecting pipe 6 is stainless steel, and the material of the center pipe support 7 is heat-resistant steel or stainless steel. Such materials can ensure the strength in a high-temperature environment.

[0085] Preferably, a third vertical ring 10 is provided in the inner hole at the front end of the first-stage stepped small pipe. The outer diameter of the third vertical ring 10 is 1 - 3 mm smaller than the inner diameter of the first-stage stepped small pipe. The inner hole is such that the gas generated here can be collected in time. The outer wall of the third vertical ring 10 is fixed to the first-stage small stepped pipe. On the first-stage stepped small pipe and behind the third vertical ring 10, the gas collecting hood 67 and the gas ventilation chamber 68 of this stage are provided.

[0086] In addition, this embodiment also provides a pyrolysis rotary kiln device, which includes the above-mentioned pyrolysis kiln.

[0087] Example 2

[0088] See Figure 3 As shown, compared with Example 1, in this example, the gas collection hood 67 and the gas vent chamber 68 on the stepped central pipe 61 and their corresponding structures are omitted. Only a plurality of symmetric air inlets 66 are provided on the pipe wall of each stage of the central pipe, and a third vertical ring 10 is provided at the front end in the smallest stepped central pipe 61 of the first stage. The outer diameter of the third vertical ring 10 is 1-3 mm smaller than the inner diameter of the small pipe of the first-stage step. The inner hole is such that the gas generated here can be collected in time. The outer periphery of the third vertical ring 10 is fixed to the small pipe of the first-stage step. The setting of the third vertical ring 10 at the front inner hole of the small pipe of the first-stage step is beneficial to blocking the material from entering the central pipe, and at the same time, part of the gas can enter through the ring holes. The rest of the structure is the same as that of Example 1.

[0089] Example 3

[0090] Compared with Example 1, the only difference is that the pipe diameter of the stepped central pipe 61 is the same as that of the sizing central pipe 62, and the rest of the structure is the same as that of Example 1.

[0091] Example 4

[0092] Compared with Example 2, the only difference is that the pipe diameter of the stepped central pipe 61 is the same as that of the sizing central pipe 62, and the rest of the structure is the same as that of Example 2.

[0093] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A rotary kiln gas collecting pipe, characterized in that, It includes a stepped central tube and a sizing central tube. One end of the stepped central tube is communicated with the sizing central tube, and a plurality of air inlets are arranged on the outer peripheral wall of the stepped central tube; The diameter of the end of the stepped central tube close to the sizing central tube is larger than that of the end far from the sizing central tube, and the diameter of the stepped central tube varies in a gradient along the feeding direction; The stepped central tube is arranged at the position of the initial pyrolysis to the highest pyrolysis temperature, and the diameter gradually increases along the feeding direction, and the diameter is the largest at the highest temperature.

2. The rotary kiln gas collecting pipe according to claim 1, characterized in that, A clamping tube is arranged at the end of the stepped central tube close to the sizing central tube. The inner diameter of the clamping tube is 1-5 mm larger than the outer diameter of the sizing central tube. One end of the clamping tube close to the stepped central tube extends 50-100 mm out of the sizing central tube, and the end of the clamping tube far from the stepped central tube is fixedly connected with the sizing central tube; A plurality of guiding insertion plates are uniformly distributed on the outer wall surface of the end of the stepped central tube close to the sizing central tube in the circumferential direction. Each guiding insertion plate is stepped in the radial direction. The end with a smaller area of the guiding insertion plate is located at the end of the stepped central tube. The end with a larger area of the guiding insertion plate is vertically welded and fixed to the outer wall of the stepped central tube. And there is a gap between the end with a smaller area of the guiding insertion plate and the clamping tube. The clamping tube is inserted into the stepped central tube through the guiding of the guiding insertion plate, and the stepped central tube and the sizing central tube are communicated.

3. The rotary kiln gas collecting pipe according to claim 2, characterized in that, The stepped central tube is formed by connecting multiple small stepped tubes through a first vertical ring, and air inlets are arranged on the outer peripheral wall of each small stepped tube. A plurality of ventilation holes one are uniformly arranged on the first vertical ring.

4. The rotary kiln gas collecting pipe according to claim 3, characterized in that, A gas collection hood and a gas ventilation chamber are arranged on each stepped small tube. Except for the first stepped small tube with the smallest outer diameter, the gas collection hoods of the remaining stepped small tubes are arranged at the rear end of the previous stepped small tube. The gas ventilation chamber is arranged at the end of the current stepped small tube close to the air inlet. One end of the gas collection hood is communicated with the outside, and the other end of the gas collection hood is communicated with the gas ventilation chamber through a plurality of the ventilation holes one. The gas ventilation chamber is fixed on the outer periphery of the stepped small tube, and the gas ventilation chamber is communicated with the inside of the stepped small tube through the air inlet.

5. The rotary kiln gas collecting pipe according to claim 4, characterized in that, The gas collection hood includes a first cylinder and a first vertical ring. The first cylinder is arranged at the end of the previous stepped small tube of the current stepped small tube. The outer diameter of the first vertical ring is 0.5-3 mm smaller than the inner wall of the first cylinder. The inner diameter of the first vertical ring is 0.5-3 mm larger than the outer diameter of the previous stepped small tube of the current stepped small tube. And the inner peripheral wall of the first cylinder is fixedly connected with the outer wall of the previous stepped small tube through the first vertical ring, and the outer wall of the first vertical ring is fixedly connected with the inner wall of the first cylinder.

6. The rotary kiln gas collecting pipe according to claim 5, characterized in that, The first cylinder has a cavity, and a spiral blade is arranged in the cavity.

7. The rotary kiln gas collecting pipe according to claim 6, characterized in that, The gas vent chamber includes a second cylinder and a second vertical ring. The outer diameter of the second cylinder on the same-stage stepped small pipe is smaller than that of the first cylinder, and the inner diameter of the second cylinder is larger than the outer diameter of the same-stage stepped small pipe. The second vertical ring is located on the same-stage stepped small pipe, and the ratio of the distance from the second vertical ring to the front end of the same-stage stepped small pipe to the total length of the same-stage stepped small pipe is greater than 1 / 2. The outer diameter of the second vertical ring is smaller than the inner diameter of the second cylinder, and the inner diameter of the second vertical ring is larger than the outer diameter of the same-stage stepped small pipe. One end of the second cylinder is fixedly connected to the outer peripheral wall of the second vertical ring through the inner wall, and the other end of the second cylinder is fixedly connected to the side wall of the first vertical ring. The inner peripheral wall of the second vertical ring is fixedly connected to the outer wall of the same-stage stepped pipe. The first vent holes are uniformly arranged on the first vertical ring between the first cylinder and the second cylinder.

8. The rotary kiln gas collecting pipe according to claim 7, characterized in that, A third vertical ring is arranged in the front inner hole of the first-stage stepped small pipe of the multi-stage stepped pipe. The outer diameter of the third vertical ring is 1-3 mm smaller than the inner diameter of the first-stage stepped small pipe. The outer wall of the third vertical ring is fixed to the first-stage stepped small pipe. A gas collection hood and a gas vent chamber of this stage are arranged behind the third vertical ring.

9. A pyrolysis rotary kiln device, characterized in that, It includes a kiln body and the rotary kiln gas collector pipe according to any one of claims 1-8. A plurality of pipe supports are arranged on the outer wall of the rotary kiln gas collector pipe. The plurality of pipe supports are fixedly connected to the inner liner of the kiln body through a central pipe support. Each pipe support corresponds to a row of central pipe supports, and each row of central pipe supports is provided with 3-6 central pipe sub-supports; the pyrolysis rotary kiln device further includes a feeding hood. A gas outlet is arranged at the top of the feeding hood, and a pyrolyzed coal outlet is arranged at the bottom of the feeding hood. The end of the sizing central pipe far from the stepped central pipe extends 500-1000 mm beyond the discharge end of the rotary kiln to reach the position of the feeding hood. The position of the smallest diameter end of the stepped central pipe is spatially located at the position where pyrolysis begins in the pyrolysis rotary kiln. The pyrolysis rotary kiln includes a rotary kiln body, a hot air hood arranged on the outer periphery of the rotary kiln body, a plurality of uniformly distributed heating pipes arranged parallel to the inner wall of the kiln body, and a rotary kiln gas collector pipe.

10. The pyrolysis rotary kiln device according to claim 9, characterized in that, Each of the pipe supports includes 2-6 pipe support legs and 1 pipe support surface. One end of the pipe support legs is fixedly connected to the outer arc surface of the rotary kiln gas collector pipe, and the other end of the pipe support legs is fixedly connected to the pipe support surface. The central pipe support includes a leg and a support surface. The end of the leg far from the support surface is fixedly connected to the inner liner of the kiln body, and the other end of the leg is fixedly connected to the support surface. A plurality of first bolt through holes are arranged on the support surface. A second bolt through hole corresponding to the first bolt through hole is arranged on each row of the pipe support surfaces. A gap is arranged radially between the pipe support surface and the support surface.

11. The pyrolysis rotary kiln device according to claim 10, characterized in that, At least one row of the first bolt through holes and the second bolt through holes on the pipe support surface and the support surface are all round holes.

12. The pyrolysis rotary kiln device according to claim 11, characterized in that, At least one row of the first bolt through holes and / or the second bolt through holes on the pipe support surface and the support surface are all long holes.

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