A water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler

Abstract

This utility model relates to the field of zinc oxide rotary kiln technology, and more particularly to a water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler. It includes a settling chamber body and a foundation platform. The settling chamber body is installed on the foundation platform and includes an upper box structure and a lower boat-shaped structure. The box structure is composed of side wall membrane water-cooled walls, upper side headers, upper front headers, upper front wall membrane water-cooled walls, upper rear headers, and upper rear wall membrane water-cooled walls, forming an upper chamber. The upper front wall membrane water-cooled walls have through holes for the rotary kiln to be inserted and connected. The upper side headers have an outlet flue with a square-round section connecting to an external waste heat boiler. The bottom of the boat-shaped structure has multiple discharge hoppers. This utility model replaces the refractory-lined settling chamber with a water-cooled settling chamber, allowing the recovery of the unrecovered flue gas temperature drop in this section, increasing the steam production of the waste heat boiler; the return material temperature in the bottom discharge hoppers is reduced, decreasing the physical sensible heat loss of the material and improving the surrounding operating environment.

Description

Technical Field

[0001] This utility model relates to the field of zinc oxide rotary kiln technology, and in particular to a water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler. Background Technology

[0002] Zinc oxide rotary kilns are widely used in processes involving the calcination and reduction of zinc-containing waste materials to recover valuable elements such as metallic zinc. During normal operation, the material and flue gas flow counter-currently within the kiln. The material is added at the kiln tail for high-temperature calcination, while slag is discharged from the kiln head. The high-temperature flue gas generated during calcination is drawn out from the kiln tail. The high-temperature flue gas exiting from the kiln tail has a high velocity and carries some of the newly added material out of the kiln. During operation, the kiln contains reducing gases. Metallic zinc and zinc oxide particles volatilized from the high-temperature reduction gasification also exit the kiln tail with the hot flue gas. Unburned particles of coking coal and other fuels mixed in with the material are also carried out. Therefore, conventional zinc oxide rotary kilns typically have a refractory-lined oxidation settling chamber after the kiln tail to collect the material particles carried out by the flue gas for re-feeding. The reduced metallic zinc in the flue gas undergoes further oxidation to form zinc oxide, releasing heat. Unburned coal particles carried in the flue gas also continue to burn, generating significant amounts of heat.

[0003] However, the oxidation settling chambers constructed with refractory materials are very large and lack flue gas heat recovery. Conventional zinc oxide rotary kiln waste heat boilers are all located after the oxidation settling chamber, resulting in very high temperatures inside the chamber and significant heat dissipation due to its large surface area. High-temperature settling material particles are also discharged from the ash hopper, further increasing heat loss. Because the insulated settling chamber frequently experiences high-temperature ash accumulation and coking, frequent manual cleaning leads to significant cold air leakage, causing large amounts of cold air to leak into the oxidation settling chamber, further shifting flue gas heat downstream and increasing exhaust heat loss. Some oxidation settling chambers use a water tank cover design on top, relying on circulating water for cooling and heat removal, which results in even greater heat loss. Utility Model Content

[0004] This utility model provides a water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler to solve the above-mentioned technical problems.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler includes a settling chamber body and a foundation platform. The settling chamber body is installed on the foundation platform. The settling chamber body includes an upper box structure and a lower boat-shaped structure. The box structure is composed of a side wall membrane water-cooled wall, a side upper header, a front wall upper header, a front wall membrane water-cooled wall, a rear wall upper header, and a rear wall membrane water-cooled wall connected to form an upper chamber. The front wall membrane water-cooled wall has a through hole for the rotary kiln to be inserted and connected. The side upper header has an outlet square-round section flue connected to an external waste heat boiler. The bottom of the boat-shaped structure has multiple discharge hoppers.

[0007] The water circulation system employs a natural circulation design, with a front membrane water-cooled wall and a rear membrane water-cooled wall. Both the front and rear membrane water-cooled walls are vertical and connected to the header at both ends. The front membrane water-cooled wall is designed with an opening that allows the rotary kiln to be inserted as a whole. The diameter of the opening is larger than the outer diameter of the rotary kiln, and the gap size ensures that the front membrane water-cooled wall is not worn during the hot rotation of the rotary kiln. The two sides of the front wall are connected to the side membrane water-cooled walls to form a robust, integrated structure.

[0008] Furthermore, the inner cavity of the settling chamber body is provided with at least two partition membrane water-cooled walls, the surfaces of which are arranged along the width direction of the settling chamber body. Depending on process requirements, the number of partition membrane water-cooled walls can be 0, 2, or more. When no partition membrane water-cooled walls are provided, the inner cavity of the settling chamber body is a completely empty chamber design. When two or more partition membrane water-cooled walls are provided, the multiple partition membrane water-cooled walls are arranged in a staggered manner, causing the flue gas to form multiple "N"-shaped turning flows to achieve a better settling effect.

[0009] Furthermore, the upper side headers are also equipped with steam and water outlet pipe seats, and the two upper side headers are connected by a connecting short pipe. A connecting short pipe is provided between the two upper side headers to form an overall stable structure. The lower side header is designed with a water inlet pipe seat. The water and steam inlet pipe seats of the upper and lower headers are ultimately connected to the external waste heat boiler through pipelines to form a natural circulation loop.

[0010] Furthermore, the hull-shaped structure comprises a lower chamber formed by connecting a front wall membrane water-cooled wall, a front wall lower header, side wall membrane water-cooled walls, side lower headers, and a rear wall lower header. The lower chamber is equipped with a water inlet pipe seat. The lower parts of the side wall membrane water-cooled walls also curve inwards to form a hull shape, with the angle of inclination ensuring it is greater than the angle of repose to facilitate material sliding. The side lower headers also maintain a certain distance and are arranged slightly outwards at the bottom to allow multiple discharge hoppers to be located at the bottom.

[0011] Furthermore, the steam and water outlet pipe seats of the upper and lower side headers are both connected to the boiler drum of the external waste heat boiler through pipes.

[0012] Furthermore, the side upper header includes a side rear upper header located at the rear end of the box structure, and the outlet square-round section flue is disposed on the side rear upper header. The upper rear part of the settling chamber body is designed with two separate header sections, which are separated from the side wall membrane water-cooled wall headers on both sides, with a wider spacing, and the outlet square-round section flue is arranged here.

[0013] Furthermore, the upper part of the side wall membrane water-cooled wall bends inward to form a canopy. Both side walls are membrane water-cooled walls, connected to the headers at both the top and bottom. The upper part of the side walls bends inward to form a canopy, and maintains a certain gap between the left and right upper headers so that the rotary kiln's feed pipe can pass through obliquely.

[0014] Furthermore, a feeding pipe is provided through the side header and the header on the front wall, and the lower end of the feeding pipe is guided to the external rotary kiln.

[0015] Furthermore, the partition wall membrane water-cooled wall comprises multiple tubes arranged at equal intervals, and the multiple tubes are connected by flat steel. All partition wall membrane water-cooled walls are heat-receiving surfaces made of multiple tubes 21 with flat steel welded to both sides at equal intervals.

[0016] Furthermore, the basic platform is provided with multiple supports for supporting the settling chamber body, and the supports are located on both sides of the settling chamber body.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. This utility model maintains the original process requirements and the overall layout of the oxidation settling chamber design, so that the collection and return of materials can be realized normally;

[0019] 2. This utility model replaces the oxidation settling chamber built with refractory materials with a water-cooled settling chamber, enabling the recovery of the unrecovered flue gas temperature drop in this section, increasing the steam production of the waste heat boiler by approximately 30%;

[0020] 3. Due to the cooling effect of the water-cooled settling chamber, the return temperature of the bottom discharge hopper is reduced, which reduces the physical sensible heat loss of the material and improves the surrounding operating environment.

[0021] 4. This utility model solves the problem that oxidation settling chambers built with refractory materials cannot be mechanically cleaned, reduces the labor cost of manual cleaning, and improves the level of mechanization and automation of the equipment. Attached Figure Description

[0022] Figure 1 This is a planar perspective structural diagram of the present invention;

[0023] Figure 2 This is a schematic diagram of the left side of this utility model;

[0024] Figure 3This is a cross-sectional schematic diagram of the present invention;

[0025] Figure 4 This is a top view of a membrane water-cooled wall.

[0026] Figure 5 This is a structural schematic diagram of Embodiment 3;

[0027] Figure 6 This is a schematic diagram of the flue gas flow in Example 3;

[0028] Attached diagram labels: 1-Settling chamber body, 2-Side wall membrane water-cooled wall, 3-Upper side header, 4-Lower side header, 5-Feeding pipe, 6-Discharge hopper, 7-Steam and water outlet pipe seat, 8-Connecting short pipe, 9-Water inlet pipe seat, 10-Front wall membrane water-cooled wall, 11-Front wall upper header, 12-Front wall lower header, 13-Rear wall membrane water-cooled wall, 14-Rear wall upper header, 15-Rear wall lower header, 16-Side rear upper header, 17-Outlet square-round flue, 18-Partition wall membrane water-cooled wall, 19-Partition wall upper header, 20-Partition wall lower header, 21-Pipe, 22-Flat steel, 23-Support, 24-Foundation platform. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0030] Example 1, as Figures 1-4 As shown, this utility model discloses a water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler, including a settling chamber body 1 and a foundation platform 24. The settling chamber body 1 is installed on the foundation platform 24. The settling chamber body 1 includes an upper box structure and a lower boat-shaped structure. The box structure is composed of a side wall membrane water-cooled wall 2, a side upper header 3, a front wall upper header 11, a front wall membrane water-cooled wall 10, a rear wall upper header 14, and a rear wall membrane water-cooled wall 13 connected to form an upper chamber. The front wall membrane water-cooled wall 10 has a through hole for the rotary kiln to be inserted and connected. The side upper header 3 has an outlet square-round section flue 17 connected to the external waste heat boiler. The bottom of the boat-shaped structure has multiple discharge hoppers 6.

[0031] Specifically, the water circulation adopts a natural circulation design. The front of the tank consists of a header 11 and a front membrane water-cooled wall 10 on the front wall, while the rear of the tank consists of a header 14 and a rear membrane water-cooled wall 13 on the rear wall. Both the front and rear membrane water-cooled walls 10 and 13 are vertical membrane water-cooled walls, connected to the headers at the top and bottom. The front membrane water-cooled wall 10 is designed with a hole that allows the rotary kiln to be inserted as a whole. The diameter of the hole is larger than the outer diameter of the rotary kiln, and the gap size ensures that the front membrane water-cooled wall 10 is not worn during the hot rotation of the rotary kiln. The two sides of the front wall are connected to the side membrane water-cooled walls 2 on both sides to form a solid overall structure.

[0032] The settling chamber body 1 has at least two partition membrane water-cooled walls 18 inside its cavity, with the surface of the partition membrane water-cooled walls 18 arranged along the width direction of the settling chamber body 1. Specifically, depending on process requirements, the number of partition membrane water-cooled walls 18 is 0, 2, or more. When no partition membrane water-cooled walls 18 are provided, the cavity of the settling chamber body 1 is a completely empty chamber design. When two or more partition membrane water-cooled walls 18 are provided, the multiple partition membrane water-cooled walls 18 are arranged vertically and horizontally in a staggered manner, causing the flue gas to form multiple "N"-shaped turning flows to achieve a better settling effect.

[0033] The upper side header 3 is also equipped with a steam and water outlet pipe seat 7, and the two upper side headers 3 are connected by a connecting short pipe 8. Specifically, a connecting short pipe 8 is provided between the two upper side headers 3 to form an overall stable structure, and the lower side header 4 is designed with a water inlet pipe seat 9. The water and steam inlet and outlet pipe seats of the upper and lower headers are ultimately connected to the external waste heat boiler through pipes to form a natural circulation loop.

[0034] The boat-shaped structure consists of a front wall membrane water-cooled wall 10, a front wall lower header 12, side lower headers 4, a rear wall membrane water-cooled wall 13, and a rear wall lower header 15 connected to form a lower chamber. The lower chamber is equipped with a water inlet pipe seat 9. Specifically, the lower parts of the side wall membrane water-cooled walls 2 on both sides are also inclined inwards to form a boat shape. The inclination angle must be greater than the angle of repose to facilitate material sliding. The side lower headers 4 also maintain a certain spacing and are arranged slightly outwards at the bottom to allow multiple discharge hoppers 6 to be arranged at the bottom.

[0035] The steam and water outlet pipe seats 7 of the upper side header 3 and the lower side header 4 are both connected to the boiler drum of the external waste heat boiler through pipes.

[0036] The upper side header 3 includes a rear upper side header 16 located at the rear end of the box structure, and the outlet square-round section flue 17 is disposed on the upper side header 16. Specifically, the upper rear part of the settling chamber body 1 is designed with two separate headers, which are separated from the headers on the side wall membrane water-cooled walls 2 on both sides, with a wider spacing, and the outlet square-round section flue 17 is arranged here.

[0037] The upper part of the side wall membrane water-cooled wall 2 bends inward to form a canopy. Specifically, both side walls are membrane water-cooled walls, connected to the headers at both the top and bottom. The upper part of the side walls bends inward to form a canopy, and maintains a certain gap between the left and right upper headers so that the feed pipe 5 of the rotary kiln can pass through obliquely.

[0038] A feeding pipe 5 is provided through the side upper header 3 and the front wall header 11, and the lower end of the feeding pipe 5 is guided to the external rotary kiln.

[0039] The partition wall membrane water-cooled wall 18 comprises multiple tubes 21 arranged at equal intervals, and the multiple tubes 21 are connected by flat steel 22. Specifically, all partition wall membrane water-cooled walls 18 are heat-receiving surfaces made by welding flat steel 22 between multiple tubes 21 at equal intervals on both sides.

[0040] The base platform 24 is provided with a plurality of supports 23 for supporting the settling chamber body 1, and the supports 23 are located on both sides of the settling chamber body 1.

[0041] Example 2, based on Example 1, proposes a specific working principle of a water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler.

[0042] The specific implementation principle and process are as follows:

[0043] The settling chamber body 1 is composed of the following integral structure: two side wall membrane water-cooled walls 2, with the upper and lower ends welded to the upper side header 3 and the lower side header 4, respectively. The upper part of the side wall membrane water-cooled walls 2 bends inward to form a roof. A suitable gap is left between the two upper side headers 3, allowing the rotary kiln's feed pipe 5 to be inserted obliquely through this gap at the upper front, with the angle adjustable arbitrarily. The lower part of the side wall membrane water-cooled walls 2 also bends inward to form a boat shape. The two lower side headers 4 also maintain a certain gap. The side wall membrane water-cooled walls 2 are arranged with a slight outward bend at the bottom of the boat shape, facilitating the placement of multiple discharge hoppers 6 at the bottom.

[0044] The front wall membrane water-cooled wall 10 is designed vertically, connecting to the upper front wall header 11 and the lower front wall header 12 at the top and bottom, respectively. The two sides of the front wall connect to the side wall membrane water-cooled walls 2, forming a robust integrated structure. The upper front wall header 11 is equipped with steam and water outlet pipe seats 7, and the lower front wall header 12 is equipped with a water inlet pipe seat 9. Both the upper and lower header inlet and outlet water and steam pipe seats are ultimately connected to the waste heat boiler drum via pipes, forming a natural water circulation loop.

[0045] The rear wall membrane water-cooled wall 13 is also designed to be vertical, connecting to the upper and lower headers 14 and 15 respectively. The two sides of the rear wall are also connected to the side wall membrane water-cooled walls 2, forming a robust overall structure. The upper header 14 is equipped with steam and water outlet pipe seats 7, and the lower header 15 is equipped with a water inlet pipe seat 9. Both the upper and lower header inlet and outlet water and steam pipe seats are ultimately connected to the waste heat boiler drum via pipes, forming a natural water circulation loop.

[0046] To address the technical problem of waste heat loss, this utility model provides a water-cooled settling chamber design for a zinc oxide rotary kiln waste heat boiler, replacing the oxidation settling chamber constructed with refractory materials. It is also one of the heating surface components of the zinc oxide waste heat boiler, responsible for recovering the flue gas heat lost in the oxidation settling chamber, thereby improving the overall waste heat recovery efficiency and increasing the steam output of the waste heat boiler by about 30%.

[0047] Example 3: Based on Example 1, this example proposes a structure for a settling chamber body with two partition membrane water-cooled walls.

[0048] The settling chamber body 1 has left and right rear upper headers 16 at its upper rear, separated from the upper headers of the side membrane water-cooled walls 2 with a wider spacing. The outlet square-round section flue 17 is arranged at this wider spacing. Inside the settling chamber body 1, there are two vertically designed partition membrane water-cooled walls 18, which are connected to the upper partition wall header 19 and the lower partition wall header 20 respectively. The first wall extends downward from the top of the settling chamber body 1, and the second wall extends upward from the bottom of the settling chamber body 1. They have the same structure but are arranged at different heights and positions. Through the setting of the two partition walls, the flue gas flows in an "N" shaped trajectory inside the water-cooled settling chamber. By utilizing gravity and centrifugal force, a better settling effect can be obtained. The above structure forms an overall horizontal self-supporting boat-shaped box structure, and the water circulation adopts a natural circulation design.

[0049] The typical operating parameters for the oxidation settling chamber are as follows: the flue gas temperature at the tail of the zinc oxide rotary kiln is approximately 650-700℃. After heat dissipation through the oxidation settling chamber, the flue gas temperature will decrease, and the temperature of the flue gas entering the waste heat boiler is generally 500-600℃, resulting in a temperature loss of 100-150℃. The waste heat boiler after the settling chamber typically recovers waste heat from a flue gas temperature that has dropped from 500-600℃ to 250-300℃, with an average recovered flue gas temperature drop of approximately 250-300℃. Based on this calculation, the heat loss due to the flue gas temperature drop in the settling chamber accounts for a significant proportion, causing the evaporation rate loss of the zinc oxide rotary kiln waste heat boiler to be approximately 30%.

[0050] Of course, there may be other embodiments of this utility model. Without departing from the spirit and essence of this utility model, those skilled in the art can make various corresponding changes and modifications based on this utility model, but these corresponding changes and modifications should all fall within the protection scope of the appended claims of this utility model.

Claims

1. A water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler, comprising a settling chamber body (1) and a foundation platform (24), wherein the settling chamber body (1) is installed on the foundation platform (24), characterized in that: The settling chamber body (1) includes an upper box structure and a lower boat-shaped structure. The box structure is composed of a side wall membrane water-cooled wall (2), a side upper header (3), a front upper header (11), a front wall membrane water-cooled wall (10), a rear upper header (14), and a rear wall membrane water-cooled wall (13) connected to form an upper chamber. The front wall membrane water-cooled wall (10) has a through hole for the rotary kiln to be inserted and connected. The side upper header (3) has an outlet square-round section flue (17) connected to an external waste heat boiler. The bottom of the boat-shaped structure has multiple discharge hoppers (6).

2. The water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler according to claim 1, characterized in that: The inner cavity of the settling chamber body (1) is provided with at least two partition membrane water-cooled walls (18), and the plate surface of the partition membrane water-cooled walls (18) is arranged along the width direction of the settling chamber body (1).

3. The water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler according to claim 1, characterized in that: The upper side header (3) is also provided with a steam and water outlet pipe seat (7), and the two upper side headers (3) are connected by a connecting short pipe (8).

4. The water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler according to claim 3, characterized in that: The ship-shaped structure is composed of a front wall membrane water-cooled wall (10), a front wall lower header (12), a side lower header (4), a rear wall membrane water-cooled wall (13), and a rear wall lower header (15) connected to form a lower chamber, and the lower chamber is provided with a water inlet pipe seat (9).

5. The water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler according to claim 4, characterized in that: The steam and water outlet pipe seats (7) of the upper side header (3) and the lower side header (4) are connected to the boiler drum of the external waste heat boiler through pipes.

6. The water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler according to claim 1, characterized in that: The side upper header (3) includes a side rear upper header (16) located at the rear end of the box structure, and the outlet square-round section flue (17) is disposed on the side rear upper header (16).

7. The water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler according to claim 1, characterized in that: The upper part of the sidewall membrane water-cooled wall (2) bends inward to form a roof, and the lower part bends inward to form a boat-shaped structure.

8. The water-cooled settling chamber of a zinc oxide rotary kiln waste heat boiler according to claim 1, characterized in that: Feeding pipes (5) are provided through the side upper header (3) and the front wall header (11), and the lower end of the feeding pipes (5) is guided to the external rotary kiln.

9. The water-cooled settling chamber for a zinc oxide rotary kiln waste heat boiler according to claim 2, characterized in that: The partition wall membrane water-cooled wall (18) consists of multiple pipes (21) arranged at equal intervals, and the multiple pipes (21) are connected by flat steel (22).

10. The water-cooled settling chamber of a zinc oxide rotary kiln waste heat boiler according to claim 1, characterized in that: The base platform (24) is provided with a plurality of supports (23) for supporting the settling chamber body (1), and the supports (23) are located on both sides of the settling chamber body (1).

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