Automatic Ash Discharging and Coke Removal Device and Method for Straw Boiler

Abstract

Boilers burning straw fuel often form a coking layer similar to a bridge or a roof in the combustion barrel. At this time, the operation must be interrupted and manual coke removal is required. The coking problem of straw biomass boilers has always been one of the biggest problems plaguing the normal operation of current straw biomass boilers, which has affected the development and utilization of straw biomass mainly composed of agricultural waste, not only wasting resources but also bringing huge pressure to the environment. The present invention uses a slag stirring impeller that can rotate for slag discharge and cooperates with a coke-breaking rod that can remove the bridging coke or roof coke in the combustion barrel, enabling the boiler to fully automatically and comprehensively remove coking, overcoming the defect that the current drum coke removal device can only remove coke lumps in local and low positions.

Description

Technical Field

[0001] The present invention relates to the technical field of boilers, and in particular to an automatic ash and coke removal device for a straw boiler that can remove boiler coking online. Background Art

[0002] Biomass pellet fuels are divided into two major categories by category. One is the woody biomass pellet fuel processed from wood, wood chips, and tree branches, referred to as wood pellets for short. Wood pellets have a high calorific value, low ash content, do not coke during combustion, and do not emit black smoke. They are the preferred fuel for most small household biomass boilers at present, but the resources are limited and not suitable for large-scale promotion. The other is the straw biomass pellet fuel processed from crop waste, referred to as straw pellets for short. Straw pellets have an unstable calorific value, high ash content, are prone to coking during combustion, and are prone to emitting black smoke, but the resources are extremely rich and suitable for large-scale promotion.

[0003] In China, the amount of straw biomass mainly composed of crop waste is huge, nearly 900 million tons are produced every year, and these biomasses are widely and scattered, and it is difficult to collect and transport. If not utilized, it will not only waste resources but also bring great pressure to the environment. And it is also one of the effective ways to solve this problem for household residents to use straw pellets for heating nearby. However, when burning straw fuel in the boiler, when the furnace temperature exceeds 900 °C, large-area coking will occur. In most cases, a coking layer similar to a bridge or a roof will be formed in the combustion barrel, and the operation must be interrupted and manual coke removal is required. Although there are many current coke removal technologies and methods, such as CN201820962437.7, CN201721155232.X, etc., they can only remove local and low-position coke lumps, and none of them can reach the above-mentioned higher-position bridging coke or roof coke. Therefore, currently, the straw boilers on the market mainly choose straw biomass pellet fuels containing anti-coking additives, or adopt technical methods to reduce the boiler combustion temperature to prevent coking, but the effect is limited.

[0004] Therefore, it is necessary to provide an automatic ash and coke removal device for a straw boiler to solve the above technical problems. Summary of the Invention

[0005] To solve the above problems, the present invention provides a new automatic ash and coke removal device for a straw boiler.

[0006] The present invention is mainly solved by the following specific technical solutions:

[0007] A self - discharging ash and removing coke device for a straw boiler, characterized in that: it includes a slag stirring impeller 1, a power driving part, a position detecting part and a control part; a coke breaking rod 6 is installed on the slag stirring impeller 1, which is connected to the slag stirring shaft 2, fixed on the boiler structure through two bearing seats 3, and connected to the power driving part, and the slag stirring impeller 1 is installed at the lower part of the combustion barrel 4.

[0008] Preferably, the combustion barrel 4 is an inverted frustum - shaped, or inverted quadrangular frustum - shaped, or upper - square lower - circular, or upper - circular lower - square, or upper - circular lower - elliptical, or upper - square lower - elliptical hollow barrel without a cover on the top and a bottom on the bottom, and ventilation holes 5 with a diameter of 3 mm to 20 mm are evenly distributed around the barrel body.

[0009] Preferably, the bottom plane of the combustion barrel 4 extends along the diameter line of the circle, or the center line of the opposite sides of the square, or the long axis of the ellipse, and two semi - circular notches adapted to the diameter of the slag stirring shaft 2 are cut at the edge of the combustion barrel to position or support the combustion barrel 4 on the slag stirring shaft 2. The radial projection contour of the slag stirring impeller 1 is consistent with the shape of the bottom of the combustion barrel 4. After assembly, the axis of the slag stirring impeller 1 coincides with the plane of the barrel bottom, and it is ensured that the slag stirring impeller 1 can rotate freely.

[0010] Preferably, the slag stirring impeller 1 discharges ash and removes coke in a forward and reverse rotation manner. The number of blades of the slag stirring impeller 1 should be between 5 and 15. All blades open in the radial direction of the axis, and at least one coke breaking rod 6 that can rotate around the slag stirring shaft 2 is installed. However, there is a sealing blade 7 among the blades. Restricted by the sealing blade 7 and the coke breaking rod 6, the rotation of the slag stirring impeller 1 does not exceed one circle. The coke breaking rod 6 has a hole that can be sleeved on the slag stirring shaft 2, and the coke breaking rod 6 extends into the combustion barrel 4.

[0011] Preferably, the position detecting part is provided with a coke breaking induction stud 8 on the slag stirring shaft 2, and a coke breaking inductive proximity switch 9 is installed on the trajectory of the coke breaking induction stud 8 rotating with the slag stirring shaft 2, and the switch is triggered to act when the coke breaking induction stud 8 approaches the induction head of the coke breaking inductive proximity switch 9.

[0012] Preferably, the power driving part is driven by a reduction motor 10 to drive a gear transmission group 11, which in turn drives the slag stirring shaft 2 and the slag stirring impeller 1 to rotate.

[0013] Preferably, as a simplified slag discharging method, the coke breaking rod 6, the sealing blade 7, the coke breaking induction stud 8, the coke breaking inductive proximity switch 9 can be cancelled, and all blades do not need to open in the radial direction of the axis from the middle, that is, a rodless slag stirring impeller 12.

[0014] Preferably, a slag discharging and coke breaking method for an automatic ash discharging and coke removing device of a straw boiler is characterized in that: the control part reads the state of the position detection part, and then controls and drives the power drive part to drive the rotation time and rotation direction of the slag stirring impeller 1 to complete the slag discharging and coke breaking operations; a slag discharging action consists of a clockwise rotation plus a counterclockwise rotation, and a direction control time is added in the clockwise direction, that is, the clockwise rotation time is greater than the counterclockwise rotation time, so the overall rotation direction of the slag stirring impeller 1 is clockwise. After multiple slag discharging actions, the sealing blade 7 will surely rotate to and push the coke breaking rod 6 to rotate in the clockwise direction. While the coke breaking rod 6 is rotating, the coke blocks in the middle and upper parts of the combustion barrel 4 are cut, and the broken coke blocks fall into the working area of the slag stirring impeller 1 and are further crushed by the impeller and discharged. As the coke breaking induction stud 8 rotates to the position where it triggers the coke breaking inductive proximity switch 9, a coke breaking process ends. Then the control part adjusts the slag discharging action to a counterclockwise rotation plus a clockwise rotation, and adds a direction control time in the counterclockwise direction. After multiple slag discharging actions again, the sealing blade 7 pushes the coke breaking rod 6 to rotate in the counterclockwise direction to break the coke again until the coke breaking induction stud 8 rotates to the position where it triggers the coke breaking inductive proximity switch 9, and another coke breaking process ends. This cycle continues. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings 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 the structures shown in these drawings.

[0016] Figure 1 Structural diagram of the automatic slag discharging and coke removing combustion device according to the embodiment of the present invention;

[0017] Figure 2 Cross-sectional view of the slag stirring impeller according to the embodiment of the present invention;

[0018] Figure 3 Coke breaking position diagram in the clockwise direction according to the embodiment of the present invention;

[0019] Figure 4 Coke breaking position diagram in the counterclockwise direction according to the embodiment of the present invention;

[0020] Figure 5 Structural diagram of the multi-coke breaking rod according to the embodiment of the present invention;

[0021] Figure 6 Structural diagram of the rodless slag stirring impeller according to the embodiment of the present invention.

[0022] Explanation of the attached reference numerals:

[0023] 1 slag stirring impeller, 2 slag stirring shaft, 3 bearing housing, 4 combustion barrel, 5 ventilation holes, 6 coke breaking rod, 7 sealing blade, 8 coke breaking induction stud, 9 coke breaking inductive proximity switch, 10 reduction motor, 11 gear transmission group, 12 rodless slag stirring impeller.

[0024] The realization, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings. Specific embodiments

[0025] The following further describes the present invention with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art.

[0026] Embodiment 1:

[0027] As shown in Figure 1 、 Figure 2 、 Figure 5 A self-discharging ash and coke removal device for a straw boiler, characterized in that it comprises a slag stirring impeller (1), a power driving part, a position detecting part and a control part; a coke breaking rod 6 is installed on the slag stirring impeller (1) and is connected to the slag stirring shaft (2), and is fixed on the boiler structural member through two bearing housings (3) and is connected to the power driving part. The slag stirring impeller (1) is installed at the lower part of the combustion barrel (4). The combustion barrel (4) is an inverted frustum of a cone, or an inverted frustum of a quadrangular pyramid, or a hollow barrel with a square upper part and a circular lower part, or a circular upper part and a square lower part, or a circular upper part and an elliptical lower part, or a square upper part and an elliptical lower part, without a cover at the top and without a bottom at the bottom. The periphery of the barrel body is covered with ventilation holes (5) with a diameter of 3 mm to 20 mm. The bottom plane of the combustion barrel (4) extends along the diameter line of the circle, or the bottom plane extends along the center line of the opposite sides of the square, or the bottom plane extends along the long axis of the ellipse, and two semi-circular notches adapted to the diameter of the slag stirring shaft (2) are cut at the edge of the combustion barrel to position or support the combustion barrel (4) on the slag stirring shaft (2). The radial projection contour of the slag stirring impeller (1) is the same as the shape of the bottom of the combustion barrel (4). After assembly, the axis of the slag stirring impeller (1) coincides with the plane of the bottom of the barrel, and it is ensured that the slag stirring impeller (1) can rotate freely.

[0028] Embodiment 2:

[0029] As shown in Figure 1 、 Figure 2 、 Figure 5As shown, the slag stirring impeller (1) discharges ash and removes coke by rotating forward and backward. The number of blades of the slag stirring impeller (1) should be between 5 and 15. All the blades open in the radial direction of the axis, and at least one coke-breaking rod (6) that can rotate around the slag stirring shaft (2) is installed. However, there is a sealing blade (7). Restricted by the sealing blade (7) and the coke-breaking rod (6), the rotation of the slag stirring impeller (1) will not exceed one circle. The coke-breaking rod (6) extends into the combustion barrel (4). When the bottom area of the combustion barrel (4) is large or rectangular, multiple coke-breaking rods (6) can be used. The slag stirring impeller 1 is installed at the bottom of the basket-shaped combustion barrel 4 and covers most of the bottom area, so that high-temperature furnace slag and fuel will not leak into the slag hopper to maintain necessary combustion conditions.

[0030] Embodiment 3:

[0031] As Figure 1 、 Figure 2 shown, for the position detection part, a coke-breaking induction stud (8) is provided on the slag stirring shaft (2), and a coke-breaking inductive proximity switch (9) is installed on the trajectory of the coke-breaking induction stud (8) rotating with the slag stirring shaft (2). When the coke-breaking induction stud (8) approaches the induction head of the coke-breaking inductive proximity switch (9), the switch is triggered to act. The power drive part is driven by a reduction motor (10) to drive a gear transmission group (11), which in turn drives the slag stirring shaft (2) to rotate.

[0032] Embodiment 4:

[0033] As Figure 1 、 Figure 2 、 Figure 6 shown, as a simplified slag discharging method, the coke-breaking rod (6), the sealing blade (7), the coke-breaking induction stud (8), the coke-breaking inductive proximity switch (9) can be cancelled, and all the blades do not need to open in the radial direction of the axis from the middle, that is, a rodless slag stirring impeller (12).

[0034] Embodiment 5:

[0035] As Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 6As shown, for the slag discharge and coke breaking method of the fully intelligent unattended small straw biomass boiler, when the boiler uses straw fuel and the furnace temperature exceeds 900 °C, large-area coking will occur. Usually, a coking layer similar to a bridge or a roof is formed in the combustion chamber. At this time, the rotation of the slag stirring impeller 1 can be driven by the slag stirring reduction motor 10 to complete the slag discharge and coke breaking operations. A slag discharge action consists of a clockwise rotation plus a counterclockwise rotation, and a direction control time is added in the clockwise direction, that is, the clockwise rotation time is greater than the counterclockwise rotation time. Therefore, the overall rotation direction of the slag stirring impeller (1) is clockwise. After multiple slag discharge actions, the sealing blade (7) will surely rotate to and push the coke breaking rod (6) to rotate in the clockwise direction. While the coke breaking rod (6) is rotating, the coke blocks in the middle and upper parts of the combustion barrel (4) are cut. The broken coke blocks fall into the working area of the slag stirring impeller (1) and are further crushed by the impeller and discharged. As the coke breaking induction stud (8) rotates to the position where it triggers the coke breaking inductive proximity switch (9), a coke breaking process ends. Then the control part adjusts the slag discharge action to a counterclockwise rotation plus a clockwise rotation, and a direction control time is added in the counterclockwise direction. After multiple slag discharge actions again, the sealing blade (7) pushes the coke breaking rod (6) to rotate in the counterclockwise direction to break the coke again until the coke breaking induction stud (8) rotates to the position where it triggers the coke breaking inductive proximity switch (9), and another coke breaking process ends. This cycle continues.

[0036] The above are the preferred embodiments of the present invention, and thus do not limit the patent scope of the present invention. Any equivalent structural transformation made under the concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the scope of the patent protection of the present invention.

Claims

1. An automatic ash and coke removal device for a straw boiler, characterized in that: It includes a slag stirring impeller (1), a power drive part, a position detection part and a control part; a coke breaking rod (6) is installed on the slag stirring impeller (1) and is connected to the slag stirring shaft (2), and is fixed on the boiler structural member through two bearing seats (3) and is connected to the power drive part. The slag stirring impeller (1) is installed at the lower part of the combustion barrel (4); the slag stirring impeller (1) uses a forward and reverse rotation method for ash removal and coke removal. The number of blades of the slag stirring impeller (1) should be between 5 and 15. All blades are open in the radial direction of the shaft and are equipped with at least one coke breaking rod (6) that can rotate around the slag stirring shaft (2). However, there is a sealing blade (7) among the blades. Limited by the sealing blade (7) and the coke breaking rod (6), the rotation of the slag stirring impeller (1) will not exceed one circle. The coke breaking rod (6) has a hole that can be sleeved on the slag stirring shaft (2), and the coke breaking rod (6) extends into the combustion barrel (4); the position detection part is provided with a coke breaking induction stud (8) on the slag stirring shaft (2), and a coke breaking inductive proximity switch (9) is installed on the trajectory of the coke breaking induction stud (8) rotating with the slag stirring shaft (2), and when the coke breaking induction stud (8) approaches the induction head of the coke breaking inductive proximity switch (9), the switch is triggered to act.

2. The straw boiler self-ash discharging and coke removing device according to claim 1, characterized in that: The combustion barrel (4) is an inverted frustum-shaped, or inverted quadrangular frustum-shaped, or upper square and lower circular, or upper circular and lower square, or upper circular and lower elliptical, or upper square and lower elliptical hollow barrel without a cover on the top and bottom. The periphery of the barrel body is covered with ventilation holes (5) with a diameter of 3 mm to 20 mm.

3. The self-discharging ash and coke removal device for a straw boiler according to claim 1, wherein: The bottom plane of the combustion barrel (4) extends along the diameter line of the circle, or the bottom plane extends along the center line of the opposite sides of the square, or the bottom plane extends along the long axis of the ellipse. Two semi-circular notches adapted to the diameter of the slag stirring shaft (2) are cut at the edge of the combustion barrel to position or support the combustion barrel (4) on the slag stirring shaft (2). The radial projection contour of the slag stirring impeller (1) is the same as the shape of the bottom of the combustion barrel (4). After assembly, the axis of the slag stirring impeller (1) coincides with the plane of the bottom of the barrel, and it is ensured that the slag stirring impeller (1) can rotate freely.

4. The automatic ash and coke removal device for straw boilers according to claim 1, characterized in that: The power drive part is driven by a reduction motor (10) to drive a gear transmission group (11), and then drives the slag stirring shaft (2) and the slag stirring impeller (1) to rotate.

5. A slag discharging and coke breaking method for the slag discharging and coke breaking device of the straw boiler according to any one of claims 1 to 4, characterized in that: The control part reads the state of the position detection part, and then controls and drives the power drive part to drive the rotation time and rotation direction of the slag stirring impeller (1) to complete the slag removal and coke breaking operations; A slag discharging action consists of a clockwise rotation plus a counterclockwise rotation, and a direction control time is added in the clockwise direction, that is, the clockwise rotation time is greater than the counterclockwise rotation time. Therefore, the overall rotation direction of the slag stirring impeller (1) is clockwise. After multiple slag discharging actions, the sealing blade (7) will surely rotate to and push the coke breaking rod (6) to rotate in the clockwise direction. While the coke breaking rod (6) is rotating, the coke lumps in the middle and upper parts of the combustion barrel (4) are cut, and the broken coke lumps fall into the working area of the slag stirring impeller (1) and are further crushed by the impeller and discharged. As the coke breaking induction stud (8) rotates to the position where it triggers the coke breaking inductive proximity switch (9), a coke breaking process ends. Then the control part adjusts the slag discharging action to a counterclockwise rotation plus a clockwise rotation, and adds a direction control time in the counterclockwise direction. After multiple slag discharging actions again, the sealing blade (7) pushes the coke breaking rod (6) to rotate in the counterclockwise direction to break the coke again until the coke breaking induction stud (8) rotates to the position where it triggers the coke breaking inductive proximity switch (9), and another coke breaking process ends. This cycle repeats.

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