An external economizer header system for ultra-high pressure boilers

Abstract

This invention proposes an external economizer header system for ultra-high pressure boilers, belonging to the field of coal-fired power generation boilers. It solves the problem of frequent wear and even leakage in the economizer area. It includes a tail flue, an economizer and water-cooled hanging pipes installed within the tail flue, and an economizer inlet header and an economizer outlet header installed outside the tail flue. The economizer inlet is connected to the economizer inlet header via an economizer inlet pipe, and the economizer outlet is connected to the economizer outlet header via an economizer outlet pipe. A hanging plate is provided at the bottom of the water-cooled hanging pipe, and the economizer is suspended from the water-cooled hanging pipe via the hanging plate. This invention optimizes the design of the economizer inlet and outlet headers of high-pressure / ultra-high pressure boilers from being conventionally designed inside the tail flue to being located outside the tail flue. The environment in which the headers are located is free from high-temperature, high-dust flue gas, eliminating the risk of oxidation, corrosion, and wear on the outer wall of the headers.

Description

Technical Field

[0001] This invention belongs to the field of coal-fired power generation boilers, and in particular relates to an external economizer header system for ultra-high pressure boilers. Background Technology

[0002] Currently, the capacity of individual coal-fired steam boilers in chemical enterprises is relatively small, generally below 200MW (boiler evaporation capacity of approximately 670t / h), and they mostly use high-pressure / ultra-high-pressure steam parameters. These enterprises do not have high requirements for boiler efficiency and coal consumption, but they have stringent requirements for boiler reliability and long-term continuous operation. Boiler design should avoid unplanned shutdowns due to boiler-related issues, preventing significant losses to chemical production. Due to the quality of the coal used, wear and even leaks frequently occur on low-temperature heating surfaces, especially in the economizer area. If shutdown measures are not taken promptly, more serious accidents can easily occur.

[0003] The existing economizer header arrangement in high-pressure / ultra-high-pressure boilers has the following disadvantages: In conventional high-pressure / ultra-high-pressure boilers in China, the economizer inlet header and economizer outlet header (i.e., hanging pipe header) are both located inside the flue. The environment in which the header is located is extremely harsh, especially the flue gas temperature in the economizer outlet header (hanging pipe header) which reaches about 600℃. This leads to varying degrees of risk of external wall oxidation, flue gas corrosion and wear in the economizer inlet and outlet headers.

[0004] The economizer's hanging plate is anchored at the bottom of the economizer outlet header (hanging pipe header), causing the header to bear a large amount of hanging load while bearing internal pressure. This increases the wall thickness of the header's pipes, which in turn increases the header's weight. This is not conducive to reducing boiler costs and results in poor market competitiveness.

[0005] When the economizer tube leaks due to flue gas corrosion or wear, since the economizer inlet and outlet headers are located in the high-temperature flue gas at the tail flue, the boiler can only be shut down for maintenance, and online leak sealing cannot be achieved, resulting in non-shutdown of the unit, which has a significant impact on the subsequent power and steam consumption of the workshop. Summary of the Invention

[0006] In view of this, in order to solve the technical problems mentioned in the background art, the present invention proposes an external economizer header system for ultra-high pressure boilers. The economizer header is arranged externally, and when an economizer leak occurs, the corresponding pipe can be sealed online outside the furnace without affecting the normal operation of the unit, thereby ensuring the safety and stability of steam for chemical use.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: an external economizer header system for an ultra-high pressure boiler, comprising a tail flue, an economizer and water-cooled hanging pipe disposed in the tail flue, and an economizer inlet header and an economizer outlet header disposed outside the tail flue. The economizer inlet is connected to the economizer inlet header via an economizer inlet pipe, and the economizer outlet is connected to the economizer outlet header via an economizer outlet pipe. The bottom of the water-cooled hanging pipe is provided with a hanging plate, and the economizer is suspended on the water-cooled hanging pipe through the hanging plate.

[0008] Preferably, the economizer outlet header is one unit.

[0009] Preferably, both the economizer inlet pipe and the economizer outlet pipe are provided with through-wall sleeves where they pass through the wall of the tail flue, and the through-wall sleeves are sealed and welded to the steel plate of the tail flue.

[0010] Preferably, the through-wall sleeve is used to prevent flue gas from abrading the pipe and to ensure the airtightness of the flue.

[0011] Preferably, both the economizer inlet header and the economizer outlet header are arranged on a steel frame platform outside the tail flue.

[0012] Compared with the prior art, the beneficial effects of the external economizer header system for ultra-high pressure boilers described in this invention are: 1. This invention optimizes the economizer inlet and outlet headers of high-pressure / ultra-high-pressure boilers from the conventional design of being inside the tail flue to being outside the tail flue. The environment in which the headers are located does not have high-temperature and high-dust flue gas, and there is no risk of oxidation, corrosion and wear on the outer wall of the headers.

[0013] 2. In this invention, the hanging plate of the economizer is rooted at the bottom of the hanging pipe, and the economizer outlet header (hanging pipe header) does not need to bear the hanging load of the economizer, so there is no need to increase the wall thickness of the header pipe.

[0014] 3. When the economizer tube leaks due to corrosion or wear, the present invention can achieve online leak sealing because the economizer inlet and outlet headers are arranged outside the tail flue. There is no need to shut down the furnace for maintenance, which will not cause unauthorized shutdown of the unit and will not affect the subsequent power and steam consumption of the workshop.

[0015] 4. The inlet and outlet pipes of the economizer of the present invention are connected by a steel plate and a header that pass through the tail flue; at the same time, a through-wall sleeve is installed on the inlet and outlet pipes of the economizer, and the through-wall sleeve is sealed and welded to the steel plate of the tail flue, which ensures that there is no air or ash leakage on the one hand, and also prevents wear on the pipe on the other hand.

[0016] 5. This invention not only improves the safety and stability of the unit, but also optimizes the economizer outlet header (hanging pipe header) from 2 to 1, reducing the weight of the boiler and improving the competitiveness of the product. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the economizer header system of a high-pressure / ultra-high-pressure boiler in the prior art; Figure 2 This is a schematic diagram of the structure of the external economizer header system for ultra-high pressure boilers according to the present invention; In the diagram: Economizer inlet header 1; Economizer 2; Economizer outlet header (hanging pipe header) 3; Water-cooled hanging pipe 4; Tail flue 5; Hanging plate 6; Through-wall sleeve 7. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the drawings, and not all of them. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the invention.

[0019] See Figure 1 This embodiment describes an external economizer header system for an ultra-high pressure boiler, comprising a tail flue 5, an economizer 2 and a water-cooled hanging pipe 4 disposed within the tail flue 5, and an economizer inlet header 1 and an economizer outlet header 3 disposed outside the tail flue 5. The inlet of the economizer 2 is connected to the economizer inlet header 1 through the economizer inlet pipe, and the outlet of the economizer 2 is connected to the economizer outlet header 3 through the economizer outlet pipe. The bottom of the water-cooled hanging pipe 4 is provided with a hanging plate 6, and the economizer 2 is suspended on the water-cooled hanging pipe 4 through the hanging plate 6.

[0020] The number of economizer outlet headers 3 is one.

[0021] Both the economizer inlet pipe and the economizer outlet pipe are provided with wall sleeves 7 where they pass through the wall of the tail flue 5, and the wall sleeves 7 are sealed and welded to the steel plate of the tail flue 5.

[0022] The through-wall sleeve 7 is used to prevent flue gas from abrading the pipe and to ensure the airtightness of the flue.

[0023] Both the economizer inlet header 1 and the economizer outlet header 3 are arranged on a steel frame platform outside the tail flue 5.

[0024] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. An external economizer header system for ultra-high pressure boilers, characterized in that: It includes a tail flue (5), an economizer (2) and a water-cooled hanging pipe (4) installed in the tail flue (5), and an economizer inlet header (1) and an economizer outlet header (3) installed outside the tail flue (5). The inlet of the economizer (2) is connected to the economizer inlet header (1) through the economizer inlet pipe, and the outlet of the economizer (2) is connected to the economizer outlet header (3) through the economizer outlet pipe. The bottom of the water-cooled hanging pipe (4) is provided with a hanging plate (6), and the economizer (2) is suspended on the water-cooled hanging pipe (4) through the hanging plate (6).

2. The external economizer header system for ultra-high pressure boilers according to claim 1, characterized in that: The number of economizer outlet headers (3) is one.

3. The external economizer header system for ultra-high pressure boilers according to claim 1, characterized in that: Both the economizer inlet pipe and the economizer outlet pipe are provided with wall sleeves (7) at the points where they pass through the wall of the tail flue (5), and the wall sleeves (7) are sealed and welded to the steel plate of the tail flue (5).

4. The external economizer header system for ultra-high pressure boilers according to claim 3, characterized in that: The through-wall sleeve (7) is used to prevent flue gas from abrading the pipe and to ensure the airtightness of the flue.

5. The external economizer header system for ultra-high pressure boilers according to claim 1, characterized in that: The economizer inlet header (1) and the economizer outlet header (3) are both arranged on a steel frame platform outside the tail flue (5).

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