Passive discharging device and discharging method for low-rank coal pyrolysis rotary kiln

Abstract

The invention relates to a passive discharging device and method for a low-rank coal pyrolysis rotary kiln. The passive discharging device is installed at the tail of the rotary kiln. Comprising an end plate, an L-shaped material lifting plate, a material guiding cone, an air guiding pipe, a spiral discharging barrel and a discharging outer barrel. According to the passive discharging device, gas-phase and solid-phase products in the rotary kiln can be guided out through the corresponding channels, on the basis of guaranteeing smooth discharging of upgraded coal, the flow speed of raw gas is reduced, and then the dust content in the raw gas is reduced; solid-phase products are lifted through the L-shaped lifting plate at the tail of the rotary kiln and enter the spiral discharging pipe through the distributing cone to be discharged, and operation is reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of low-rank coal pyrolysis, and in particular to a passive discharge device and a discharge method for a low-rank coal pyrolysis rotary kiln. Background Art

[0002] The pyrolysis products of low-rank coal consist of upgraded coal (solid phase) and raw coal gas (gas phase, containing dust, tar, and coal gas). When using a rotary kiln pyrolysis process, the heat source is typically input from the rear end of the rotary kiln (discharge end), and the coal to be pyrolyzed enters from the head end (feed end) of the rotary kiln. The two exchange heat in a countercurrent flow inside the rotary kiln. Because raw coal gas contains a large amount of dust and vaporized tar, to prevent tar precipitation and clogging subsequent chemical recovery pipelines, the raw coal gas should be discharged simultaneously with the upgraded coal from the higher-temperature rear end of the rotary kiln through the discharge device.

[0003] Low-rank coal pyrolysis rotary kilns typically use two types of discharge devices: an active discharge device coupled with a screw conveyor, and a passive discharge device with a spiral tube installed at the rear of the rotary kiln. Currently, passive discharge devices, which utilize a tapered barrel with a spiral tube, are often used. However, once the spiral tube diameter and pitch are determined, the discharge capacity is completely dependent on the rotation speed of the rotary kiln barrel itself. Furthermore, with passive discharge devices, both gas and solid phases are discharged through the same channel. Consequently, passive discharge devices present the following problems and drawbacks:

[0004] (1) The rotation speed of the rotary kiln is usually less than 3 rpm. When the passive spiral discharge method is used, the discharge capacity will be limited. Especially in the abnormal kiln stop state, the rotary kiln can only rely on the auxiliary transmission device to rotate slowly, and the material in the kiln cannot be discharged in time.

[0005] (2) In order to ensure basic discharge capacity, the diameter of the spiral tube should not be too small when using passive discharge mode, which requires increasing the diameter of the end sealing ring, resulting in increased sealing difficulty;

[0006] (3) The upgraded coal and raw gas are discharged from the same discharge port. After the diameter is reduced, the flow rate of the raw gas increases, which will carry away more dust and increase the difficulty of subsequent dust removal;

[0007] (4) The discharge device and the cylinder are an integrated structure, which is not conducive to the later maintenance of the components inside the kiln. Summary of the Invention

[0008] The present invention provides a passive discharge device and discharge method for a low-rank coal pyrolysis rotary kiln, which can respectively discharge the gas and solid phase products in the rotary kiln through corresponding channels. On the basis of ensuring the smooth discharge of the upgraded coal, the flow rate of the raw coal gas is reduced, thereby reducing the dust content in the raw coal gas; the solid phase products are lifted by the L-shaped lifting plate at the rear of the rotary kiln, enter the spiral discharge pipe through the dividing cone and are discharged externally, with reliable operation.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A passive discharge device for a low-rank coal pyrolysis rotary kiln is installed at the tail of the rotary kiln; it includes an end plate, an L-shaped lifting plate, a guide cone, an air guide pipe, a spiral discharge cylinder and a discharge outer cylinder; the end plate closes the open end of the tail of the rotary kiln; a guide cone is provided on the inner side of the end plate, and a discharge outer cylinder and a spiral discharge cylinder are provided on the outer side of the end plate, the spiral discharge cylinder is provided inside the discharge outer cylinder, and the inner ends of the discharge outer cylinder and the spiral discharge cylinder are both connected to the end plate; the small end of the guide cone extends into the spiral discharge cylinder, and the large end of the guide cone extends toward the inside of the rotary kiln; a plurality of L-shaped lifting plates are provided along the circumference of the guide cone, and one side of the L-shaped lifting plate is connected to the end plate to form a lifting hopper; an annular gap is provided between the end plate and the guide cone, and the guide cone is provided with a plurality of exhaust holes along the circumference connected to the air guide pipe, and the air guide pipe is located in the annular channel between the spiral discharge cylinder and the discharge outer cylinder.

[0011] An end plate inner insulation layer is provided on the inner side of the end plate, and the end plate inner insulation layer is connected to the inner insulation layer of the rotary kiln cylinder; an outer cylinder inner insulation layer is provided on the inner side of the discharge outer cylinder.

[0012] The end plate is connected to the rotary kiln cylinder through a flange, and a sealing member is provided at the connection.

[0013] The spiral discharge cylinder consists of a discharge cylinder and a plurality of spiral blades arranged on the inner wall of the discharge cylinder.

[0014] The material guide cone, the spiral discharge cylinder and the discharge outer cylinder are all coaxially arranged with the rotary kiln and rotate along with the rotary kiln.

[0015] The plurality of L-shaped material lifting plates are evenly arranged along the circumference of the material guide cone, and the air guide pipe is arranged between two adjacent L-shaped material lifting plates.

[0016] One end of the L-shaped material lifting plate is connected to the material guide cone, and the other end is connected to the rotary kiln cylinder.

[0017] A method for discharging low-rank coal from a rotary kiln for pyrolysis includes the following steps:

[0018] 1) Low-rank coal enters the kiln head of the rotary kiln, undergoes pyrolysis, and is converted into upgraded coal. The upgraded coal reaches the kiln tail as the rotary kiln rotates. The upgraded coal at the kiln tail enters the hopper composed of an L-shaped lifting plate and an end plate. As the rotary kiln rotates, it is lifted to the top of the spiral discharge drum. Under the action of its own weight, it slides through the guide cone into the spiral discharge drum below and is discharged.

[0019] 2) The heat source enters from the kiln tail of the rotary kiln and exchanges heat with the low-rank coal in countercurrent, achieving pyrolysis of the low-rank coal and generating raw coal gas at the same time; the raw coal gas enters the gas guide pipe from the exhaust holes between each lifting hopper, and is then discharged from the annular channel between the spiral discharge cylinder and the discharge outer cylinder.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1) The passive discharge device of the present invention can discharge the gas-solid two-phase products after the pyrolysis of low-rank coal through corresponding channels respectively. On the basis of ensuring the smooth discharge of the upgraded coal, it reduces the flow rate of the raw coal gas and thus reduces the dust content in the raw coal gas.

[0022] 2) By adopting the passive discharge device of the present invention, both gas and solid phase products are discharged from the high temperature section, and the tar components in the raw gas are not easily precipitated, thereby improving the stability of the subsequent chemical production process.

[0023] 3) The passive discharge device of the present invention eliminates the tapered diameter reducing section at the tail of the traditional rotary kiln, shortens the length of the rotary kiln, and is beneficial to improving the overall rigidity and thermal efficiency of the rotary kiln, while also improving the sealing effect of the tail of the rotary kiln.

[0024] 4) The passive discharge device of the present invention is connected to the drum of the rotary kiln by a flange. During the overall installation and maintenance of the rotary kiln, the passive discharge device can be disassembled as a whole to facilitate operation and construction in the kiln. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the three-dimensional structure of the passive discharge device of the present invention.

[0026] Figure 2 It is a schematic diagram of the connection between the passive discharge device and the rotary kiln of the present invention.

[0027] In the figure: 1-rear of rotary kiln; 2-passive discharge device; 2.1-cone of guide; 2.2-L-shaped lifting plate; 2.3-end plate; 2.4-insulation layer inside end plate; 2.5-discharge outer cylinder; 2.6-insulation layer inside outer cylinder; 2.7-spiral discharge cylinder; 2.8-air guide pipe. DETAILED DESCRIPTION

[0028] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0029] like Figure 1 、 Figure 2As shown, the passive discharge device of the low-rank coal pyrolysis rotary kiln described in the present invention is installed at the tail end 1 of the rotary kiln; it includes an end plate 2.3, an L-shaped lifting plate 2.2, a guide cone 2.1, an air guide pipe 2.8, a spiral discharge cylinder 2.7 and a discharge outer cylinder 2.5; the end plate 2.3 closes the open end of the rotary kiln tail 1; the inner side of the end plate 2.3 is provided with a guide cone 2.1, the outer side of the end plate 2.3 is provided with a discharge outer cylinder 2.5 and a spiral discharge cylinder 2.7, the spiral discharge cylinder 2.7 is provided inside the discharge outer cylinder 2.5, the inner end of the discharge outer cylinder 2.5 and the spiral discharge cylinder 2.7 are provided The inner ends of the cylinder 2.7 are connected to the end plate 2.3; the small end of the guide cone 2.1 extends into the spiral discharge cylinder 2.7, and the large end of the guide cone 2.1 extends into the interior of the rotary kiln; multiple L-shaped lifting plates 2.2 are arranged along the circumference of the guide cone 2.1, and one side of the L-shaped lifting plate 2.2 is connected to the end plate 2.3 to form a lifting hopper; an annular gap is provided between the end plate 2.3 and the guide cone 2.1, and multiple exhaust holes are arranged along the circumference of the guide cone 2.1 and connected to the air guide pipe 2.8. The air guide pipe 2.8 is located in the annular channel between the spiral discharge cylinder 2.7 and the discharge outer cylinder 2.5.

[0030] An end plate inner insulation layer 2.4 is provided on the inner side of the end plate 2.3, and the end plate inner insulation layer 2.4 is connected to the inner insulation layer of the rotary kiln cylinder; an outer cylinder inner insulation layer 2.6 is provided on the inner side of the discharge outer cylinder 2.5.

[0031] The end plate 2.3 is connected to the rotary kiln shell through a flange, and a sealing member is provided at the connection.

[0032] The spiral discharge cylinder 2.7 is composed of a discharge cylinder and a plurality of spiral blades arranged on the inner wall of the discharge cylinder.

[0033] The guide cone 2.1, the spiral discharge cylinder 2.7 and the discharge outer cylinder 2.5 are all coaxially arranged with the rotary kiln and rotate with the rotary kiln.

[0034] The plurality of L-shaped material lifting plates 2.2 are evenly arranged along the circumference of the material guiding cone 2.1, and the air guide pipe 2.8 is arranged between two adjacent L-shaped material lifting plates 2.2.

[0035] One end of the L-shaped material lifting plate 2.2 is connected to the material guide cone 2.1, and the other end is connected to the rotary kiln cylinder.

[0036] The present invention provides a method for discharging low-rank coal from a rotary kiln for pyrolysis, comprising the following steps:

[0037] 1) Low-rank coal enters the rotary kiln head, undergoes pyrolysis, and is converted into upgraded coal. The upgraded coal reaches the kiln tail as the rotary kiln rotates. The upgraded coal at the kiln tail enters the hopper formed by the L-shaped lifting plate 2.2 and the end plate 2.3. As the rotary kiln rotates, it is lifted to the top of the spiral discharge drum 2.7. Under its own weight, it passes through the guide cone 2.1 and slides into the spiral discharge drum 2.7 below to be discharged.

[0038] 2) The heat source enters from the kiln tail of the rotary kiln and exchanges heat with the low-rank coal in countercurrent flow, achieving pyrolysis of the low-rank coal and generating raw coal gas; the raw coal gas enters the air guide pipe 2.8 from the exhaust holes between the lifting hoppers, and is then discharged through the annular channel between the spiral discharge cylinder 2.7 and the discharge outer cylinder 2.5.

[0039] The passive discharge device of the low-rank coal pyrolysis rotary kiln described in the present invention is installed at the kiln tail of the low-rank coal pyrolysis rotary kiln (hereinafter referred to as the rotary kiln), and the guide cone 2.1, the spiral discharge cylinder 2.7 and the discharge outer cylinder 2.5 all rotate with the rotary kiln.

[0040] The passive discharge device 2 of the present invention utilizes multiple hoppers formed by an L-shaped lifting plate 2 and an end plate 2.3 at the rear end 1 of the rotary kiln to lift the material (improved coal) above a spiral discharge drum 2.7. The material then falls onto a guide cone 2.1 under its own weight and slides along the conical surface of the guide cone 2.1 into the spiral discharge drum 2.7. As the rotary kiln rotates, the upgraded coal is discharged by the spiral discharge drum 2.7.

[0041] The annular space between the outer discharge cylinder 2.5 and the spiral discharge cylinder 2.7 serves as a raw gas outlet channel, which is connected to the interior of the rotary kiln through a plurality of gas guide pipes 2.8. The gas guide pipes 2.8 pass through the guide cone 2.1 and connect to the interior of the rotary kiln.

[0042] After the low-rank coal pyrolysis rotary kiln is installed with the passive discharge device 2 of the present invention, the upgraded coal is discharged through the guide cone 2.1 and the spiral discharge cylinder 2.7, and the raw coal gas is discharged through the gas guide pipe 2.8 and the raw coal gas outlet channel, thus realizing the separate discharge of gas phase and solid phase.

[0043] An outer tube inner insulation layer 2.6 is provided inside the discharge outer tube 2.5, and an end plate inner insulation layer 2.4 is provided inside the end plate 2.3, thereby achieving thermal insulation of the rotary kiln tail 1 and reducing heat loss of raw coal gas.

[0044] By adopting the passive discharge device 2 of the present invention, the tapered diameter reducing section at the tail of the traditional rotary kiln can be eliminated, the length of the rotary kiln is shortened, which is beneficial to improving the overall rigidity and thermal efficiency of the rotary kiln and improving the sealing effect of the tail 1 of the rotary kiln.

[0045] The passive discharge device 2 of the present invention is detachably connected to the rotary kiln cylinder by a flange. During the overall installation and maintenance of the rotary kiln, the passive discharge device 2 can be completely disassembled to facilitate operations in the kiln.

[0046] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A passive discharge device for a low-rank coal pyrolysis rotary kiln, installed at the tail of the rotary kiln; characterized in that: It includes an end plate, an L-shaped material lifting plate, a material guide cone, an air guide pipe, a spiral discharge cylinder and a discharge outer cylinder; the end plate closes the open end of the rear end of the rotary kiln; a material guide cone is provided on the inner side of the end plate, and a discharge outer cylinder and a spiral discharge cylinder are provided on the outer side of the end plate. The spiral discharge cylinder is provided inside the discharge outer cylinder, and the inner ends of the discharge outer cylinder and the spiral discharge cylinder are both connected to the end plate; the small end of the material guide cone extends into the spiral discharge cylinder, and the large end of the material guide cone extends into the interior of the rotary kiln; multiple L-shaped material lifting plates are provided along the circumference of the material guide cone, and one side of the L-shaped material lifting plate is connected to the end plate to form a material lifting hopper; there is an annular gap between the end plate and the material guide cone, and the material guide cone is provided with multiple exhaust holes along the circumference connected to the air guide pipe, and the air guide pipe is located in the annular channel between the spiral discharge cylinder and the discharge outer cylinder.

2. The passive discharge device of the low-rank coal pyrolysis rotary kiln according to claim 1, characterized in that: An end plate inner insulation layer is provided on the inner side of the end plate, and the end plate inner insulation layer is connected to the inner insulation layer of the rotary kiln cylinder; an outer cylinder inner insulation layer is provided on the inner side of the discharge outer cylinder.

3. The passive discharge device of the low-rank coal pyrolysis rotary kiln according to claim 1 or 2, characterized in that: The end plate is connected to the rotary kiln cylinder through a flange, and a sealing member is provided at the connection.

4. The passive discharge device of the low-rank coal pyrolysis rotary kiln according to claim 1, characterized in that: The spiral discharge cylinder consists of a discharge cylinder and a plurality of spiral blades arranged on the inner wall of the discharge cylinder.

5. The passive discharge device of the low-rank coal pyrolysis rotary kiln according to claim 1, characterized in that: The material guide cone, the spiral discharge cylinder and the discharge outer cylinder are all coaxially arranged with the rotary kiln and rotate along with the rotary kiln.

6. The passive discharge device of the low-rank coal pyrolysis rotary kiln according to claim 1, characterized in that: The plurality of L-shaped material lifting plates are evenly arranged along the circumference of the material guide cone, and the air guide pipe is arranged between two adjacent L-shaped material lifting plates.

7. The passive discharge device of the low-rank coal pyrolysis rotary kiln according to claim 1 or 6, characterized in that: One end of the L-shaped material lifting plate is connected to the material guide cone, and the other end is connected to the rotary kiln cylinder.

8. A method for discharging low-rank coal from a rotary kiln for pyrolysis, which is based on the passive discharging device of the low-rank coal pyrolysis rotary kiln according to claim 1, 2, 4, 5 or 6; characterized in that: The process includes the following: 1) Low-rank coal enters the kiln head of the rotary kiln, undergoes pyrolysis, and is converted into upgraded coal. The upgraded coal reaches the kiln tail as the rotary kiln rotates. The upgraded coal at the kiln tail enters the hopper composed of an L-shaped lifting plate and an end plate. As the rotary kiln rotates, it is lifted to the top of the spiral discharge drum. Under the action of its own weight, it slides through the guide cone into the spiral discharge drum below and is discharged. 2) The heat source enters from the kiln tail of the rotary kiln and exchanges heat with the low-rank coal in countercurrent, achieving pyrolysis of the low-rank coal and generating raw coal gas at the same time; the raw coal gas enters the gas guide pipe from the exhaust holes between each lifting hopper, and is then discharged from the annular channel between the spiral discharge cylinder and the discharge outer cylinder.

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