Positive pressure dusty flue gas waste heat boiler

Abstract

A positive pressure dust-containing flue gas waste heat boiler relates to the technical field of boilers, and adopts the technical scheme that the positive pressure dust-containing flue gas waste heat boiler comprises a first smoke chamber, a second smoke chamber and a third smoke chamber; membrane water-cooled walls are arranged on the inner walls of the first smoke chamber, the second smoke chamber and the third smoke chamber, ash collecting hoppers are arranged at the bottoms of the first smoke chamber, the second smoke chamber and the third smoke chamber, and ash discharging valves are arranged at the bottoms of the ash collecting hoppers; an inlet flue is arranged at the top of the first smoke chamber, a connecting flue is arranged between the ash collecting hoppers of the first smoke chamber and the second smoke chamber, a connecting flue is arranged between the top openings of the second smoke chamber and the third smoke chamber, and an outlet flue is arranged on the side wall of the ash collecting hopper of the third smoke chamber; a convection bank extending towards the center of the third smoke chamber is further arranged in the third smoke chamber. The first smoke chamber, the second smoke chamber and the third smoke chamber are connected in series to form the S-shaped smoke flow channel, the ash discharging valve is arranged at the bottom of the ash collecting hopper to prevent smoke from leaking from the bottom of the ash collecting hopper under the action of positive pressure when smoke dust settles so as to adapt to a positive pressure process system, and heat is recycled through the membrane water cooling wall, the convection bank, the boiler barrel and other assemblies to generate steam.

Description

Technical Field

[0001] The utility model relates to the technical field of boilers, in particular to a positive-pressure dust-containing flue gas waste heat boiler. Background Art

[0002] After the industrial sulfur (solid or liquid) in the sulfuric acid industry is roasted, flue gas containing high mineral dust and sulfur dioxide is generated. Its temperature is between 700 and 1100 °C. It enters the waste heat boiler for heat exchange, absorbs the waste heat in the flue gas, converts the water in the boiler into high-pressure steam for power generation or industrial production steam, and at the same time reduces the dust content in the flue gas to ensure the smoothness of the process system. However, the sulfuric acid production systems operating on the market all adopt a negative-pressure operation process system. In the prior art, waste heat boilers are mainly designed for negative-pressure environments and cannot be directly applied to positive-pressure environments, otherwise flue gas leakage will occur during the heat exchange process, resulting in environmental pollution. Content of the Utility Model

[0003] Aiming at the problem that the waste heat boiler designed for the negative-pressure process system in the prior art solution cannot be applied to the positive-pressure process system, the utility model provides a positive-pressure dust-containing flue gas waste heat boiler.

[0004] The utility model provides the following technical solution: A positive-pressure dust-containing flue gas waste heat boiler includes a first flue gas chamber, a second flue gas chamber, and a third flue gas chamber; the inner walls of the first flue gas chamber, the second flue gas chamber, and the third flue gas chamber are all provided with membrane water walls, and ash hoppers are arranged at the bottoms, and a dust discharge valve is arranged at the bottom of the ash hopper; an inlet flue is arranged at the top of the first flue gas chamber, a connecting flue is arranged between the ash hoppers of the first flue gas chamber and the second flue gas chamber, a connecting flue is arranged between the top openings of the second flue gas chamber and the third flue gas chamber, and an outlet flue is arranged on the side wall of the ash hopper of the third flue gas chamber; a convection tube bundle extending towards the center of the third flue gas chamber is further arranged in the third flue gas chamber.

[0005] Preferably, it further includes a steam drum arranged above the second flue gas chamber. The steam drum is connected to the annular lower headers of the 3 membrane water walls respectively through concentrated downcomers, and the annular upper headers of the membrane water walls are connected to the steam drum through risers.

[0006] Preferably, the convection tube bundle includes a plurality of U-shaped tube groups evenly distributed around the central axis of the third flue gas chamber. Each U-shaped tube group includes multiple U-shaped tubes arranged in sequence from inside to outside, and both ends of the U-shaped tubes are connected to the membrane water wall.

[0007] Preferably, the ash hopper is in a conical shape with a larger upper part and a smaller lower part.

[0008] Preferably, a heat insulation layer is arranged on the outer surface of the ash hopper.

[0009] The beneficial effects of the present utility model are as follows: The first smoke chamber, the second smoke chamber, and the third smoke chamber are connected in series to form an S-shaped flue gas flow path. A dust discharge valve is provided at the bottom of the ash hopper to prevent the flue gas from leaking from the bottom of the ash hopper under the action of positive pressure when the soot settles, so as to adapt to the positive pressure process system, and heat is recovered by components such as membrane water walls, convection tube bundles, and drum to generate steam. Description of the Drawings

[0010] Figure 1 It is a schematic diagram of an embodiment of a waste heat boiler.

[0011] Figure 2 It is a schematic diagram of an embodiment of a convection tube bundle.

[0012] Reference numerals in the drawings: 11, the first smoke chamber; 12, the second smoke chamber; 13, the third smoke chamber; 14, the ash hopper; 15, the dust discharge valve; 16, the inlet flue; 17, the connecting flue; 18, the outlet flue; 21, the membrane water wall; 211, the annular lower header; 212, the annular upper header; 22, the convection tube bundle; 221, the U-shaped tube; 23, the drum; 24, the collective downcomer; 25, the riser tube. Detailed Embodiment

[0013] The following further describes the embodiments of the present utility model in more detail with reference to the drawings and reference numerals, so that those skilled in the art can implement it after studying this specification. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0014] The present utility model provides a Figure 1-2 positive pressure dust-containing flue gas waste heat boiler as shown, which includes a plurality of smoke chambers and a heat exchange device.

[0015] As Figure 1 shown, in this embodiment, a first smoke chamber 11, a second smoke chamber 12, and a third smoke chamber 13 are provided. Their specific structures can refer to the prior art, including structural layers such as a temperature-resistant layer, a heat-insulating layer, and a plaster layer arranged from the inside to the outside in sequence, and their outer shapes are cylindrical. The tops of the first smoke chamber 11, the second smoke chamber 12, and the third smoke chamber 13 are all open, and ash hoppers 14 are provided at the bottoms. A dust discharge valve 15 is provided at the bottom of the ash hopper 14. An inlet flue 16 is provided at the top of the first smoke chamber 11. A connecting flue 17 is provided between the ash hoppers 14 of the first smoke chamber 11 and the second smoke chamber 12. A connecting flue 17 is provided between the open tops of the second smoke chamber 12 and the third smoke chamber 13. An outlet flue 18 is provided on the side wall of the ash hopper 14 of the third smoke chamber 13, forming an S-shaped flue gas flow path.

[0016] When operating normally, the ash discharge valve 15 is closed to prevent flue gas leakage under positive pressure. The flue gas enters from the inlet flue 16, flows through the first smoke chamber, the connecting flue, the second smoke chamber, the connecting flue, and the third flue, and flows out from the outlet flue 18 to subsequent operations. The soot therein settles into the ash hopper 14 to form an ash pile. The middle and lower parts of the ash pile are regularly discharged, without causing flue gas leakage.

[0017] The heat exchange device includes membrane water walls 21 provided on the inner walls of the first smoke chamber 11, the second smoke chamber 12, and the third smoke chamber 13, and a drum 23 provided above the second smoke chamber 12. The drum 23 is respectively connected to the annular lower headers 211 of the 3 membrane water walls 21 through a centralized downcomer 24. The annular upper headers 212 of the membrane water walls 21 are connected to the drum 23 through risers 25. The water in the drum 23 flows from the centralized downcomer 24 to the annular lower headers 211 and into the membrane water walls 21. The heat radiated by the flue gas is absorbed by the water in the membrane water walls 21 to form a steam-water mixture, which reaches the drum 23 through the risers, and the steam is separated by the drum 23 and sent to subsequent operations, and the temperature of the flue gas decreases.

[0018] Furthermore, a convection tube bundle 22 extending towards the center of the third smoke chamber 13 is also provided in the third smoke chamber 13. The flue gas flows through the gaps of the convection tube bundle 22, improving the heat exchange efficiency. After the flue gas passes through the first smoke chamber and the second smoke chamber, both the temperature and the dust content are reduced, and the soot is not easily adhered to the convection tube bundle 22, which also improves the safety and stability of the boiler operation. Specifically, the convection tube bundle 22 includes a plurality of U-shaped tube groups evenly distributed around the central axis of the third smoke chamber 13; as Figure 2 shown, each U-shaped tube group includes a plurality of U-shaped tubes 221 arranged in sequence from the inside to the outside, and both ends of the U-shaped tubes 221 are connected to the membrane water wall 21.

[0019] Preferably, the ash hopper 14 is in a conical shape with a larger upper part and a smaller lower part, and a heat insulation layer is provided on the outer surface of the ash hopper 14 to reduce heat loss.

[0020] The above are one or more embodiments of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. A positive pressure dusty flue gas waste heat boiler, characterized in that: It includes a first smoke chamber, a second smoke chamber and a third smoke chamber; the inner walls of the first smoke chamber, the second smoke chamber and the third smoke chamber are all provided with membrane water-cooled walls, and the bottoms are all provided with ash hoppers, and the bottoms of the ash hoppers are provided with ash discharge valves; an inlet flue is provided at the top of the first smoke chamber, a connecting flue is provided between the ash hoppers of the first smoke chamber and the second smoke chamber, a connecting flue is provided between the top openings of the second smoke chamber and the third smoke chamber, and an outlet flue is provided on the side wall of the ash hopper of the third smoke chamber; the third smoke chamber is also provided with a convection tube bundle extending to the center of the third smoke chamber.

2. A positive pressure dusty flue gas waste heat boiler according to claim 1, characterized in that: It also includes a boiler drum arranged above the second smoke chamber, the boiler drum is connected to the three annular lower headers of the membrane water-cooled walls through centralized downcomers, and the annular upper header of the membrane water-cooled walls is connected to the boiler drum through ascending pipes.

3. The positive pressure dusty flue gas waste heat boiler according to claim 2, characterized in that: The convection tube bundle includes a plurality of U-shaped tube groups evenly distributed around the central axis of the third smoke chamber, each U-shaped tube group includes a plurality of U-shaped tubes arranged in sequence from the inside to the outside, and both ends of the U-shaped tubes are connected to the membrane water-cooled wall.

4. The positive pressure dusty flue gas waste heat boiler according to claim 1, characterized in that: The ash collecting hopper is in a cone shape that is larger at the top and smaller at the bottom.

5. The positive pressure dusty flue gas waste heat boiler according to claim 1, characterized in that: The outer surface of the ash collecting hopper is provided with a heat-insulating layer.

Images