CN202884875U

CN202884875U - Boiler flue structure

Info

Publication number: CN202884875U
Application number: CN 201220535255
Authority: CN
Inventors: 杨燕梅; 吕俊复; 张海; 吴玉新
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2012-10-18
Filing date: 2012-10-18
Publication date: 2013-04-17
Anticipated expiration: 2022-10-18

Abstract

The utility model provides a boiler flue structure, and belongs to the technical field of fuel-burning equipment. The boiler flue structure comprises a first flue, a second flue and a tail portion flue. A cooling water wall partition divides an outlet flue of a boiler furnace into a U-shaped channel, and the first flue and the second flue are arranged in the U-shaped channel in sequence along a smoke flow path and are communicated through an ash hopper in the middle. A high temperature reheater is arranged in the first flue, and a finishing superheater is arranged in the second flue. A low temperature reheater and a coal economizer and other convection heating surfaces are arranged in the tail portion flue. The ash hopper is arranged at the bottom of the U-shaped channel, and the ash hopper is not only a steering chamber for smoke flow, but also can be used for ash deposition. An air-lock device is arranged at the bottom of the ash hopper and used for eliminating the accumulated ash at regular intervals. The heating surfaces arranged in the U-shaped channel are all in a crust block type structure and are arranged in a big coarse pitch mode. The boiler flue structure can solve the problem that the boiler high temperature convection heating surfaces are stained severely.

Description

A kind of boiler flue structure

Technical field

The utility model relates to the structural design of coal-burning boiler, and particularly the high temperature convection heating surface stains serious coal-burning boiler flue structure design, belongs to the combustion apparatus technical field.

Background technology

It is inevitable phenomenon in the boiler running process that the high temperature convection heating surface stains, and affect the heating surface heat exchange, and the reduction boiler output causes the metal erosion of heating surface tube wall, stains when serious even the problem such as overtemperature tube burst can occur.Boiler flue structure reasonable in design can help to solve the contamination problem of high-temperature surface.

Accurate eastern coal volatile matter content is high, and ash content is few, easily catches fire easy to burn out.But alkali metal content is high in the accurate eastern coal, and sulfur content is also higher simultaneously.The chloride of alkalies and alkaline earth, sulfate fusing point are low, may be gaseous state or molten state under the high temperature.In addition, alkali metal also is easy to and SiO in combustion process ₂, Al ₂O ₃Deng formation low temperature eutectic, for example SiO ₂-CaO-Na ₂The fusing point of O is 720 ℃, Na ₃Al(SO ₄) ₃Fusing point is 920 ℃ etc.In certain temperature range scope (flue-gas temperature is regional at 750 ~ 900 ℃ high temperature convection heating surface), the alkali metal compound of gaseous state or low-temperature eutectic thing, meet cold cohering on heating surface, the ash particle in the flue gas also is adhered to the surface of convection heating surface gradually.This is a kind of growth dust stratification, such as untimely removing, will affect safe, stable, the efficient operation of boiler.

Accurate eastern coal high-moisture, Serious Slagging and fouling characteristics have brought very large difficulty for the safe operation of built boiler of power plant.From the situation of the accurate eastern coal of boiler combustion that put into operation at present, all found more serious coking at burner hearth, high temperature convection heating surface, middle temperature convection heating surface and low temperature convection heating surface, stain phenomenon.The main feature of accurate eastern coal coking, contamination problem is:

(1.) distributed areas are extensive, serious coking has all occured or stain phenomenon along each section of burning (flue gas) stroke heating surface;

(2.) use in the accurate eastern coal process, the heating surface position of the generation coking of different power plant and contamination is different;

(3.) use accurate eastern coal burning boiler majority and the characteristics that coking is facingd the wind growth, developed occur.

At present, the major way that solves accurate eastern coal slagging scorification and fouling characteristics is to mix burning.Power plant has summed up a series of measure through practice, and for example: improve the coal blending mode, burner reconstruction is added deslagging agent, optimizes and revises burning etc., and the dust stratification that slows down heating surface stains, and improves simultaneously mixing of accurate eastern coal and burns ratio.But this does not fundamentally solve slagging scorification, the contamination problem of the accurate eastern coal of burning.Current stage, in the boiler structure design, also there is not effective way to solve the problem that heating surface stains dust stratification.

The utility model content

The purpose of this utility model is to stain serious coal-burning boiler for the high temperature convection heating surface, proposes a kind of new boiler flue structure.

The technical solution of the utility model is as follows:

A kind of boiler flue structure is characterized in that described flue comprises the first flue, the second flue and back-end ductwork.Be the water-cooling wall partition wall between the first flue and the second flue, the first flue is communicated with into a U-shaped passage with the second flue by ash bucket, and the bottom of ash bucket is provided with flapper; In the first flue, arrange high temperature reheater, in the second flue, arrange finishing superheater, arrange low-temperature reheater and economizer in the back-end ductwork.

High temperature reheater described in the technique scheme and finishing superheater all adopt crust block formula structure, coarse pitch arrangement.

The utlity model has following advantage and outstanding effect: the design of U-shaped passage, prolonged the time that high-temperature flue gas contacts with heating surface on the one hand, can effectively slow down the dust stratification of back-end ductwork heating surface; Be beneficial on the other hand separately high-temperature surface is carried out the dust stratification cleaning.The ash bucket of U-shaped channel bottom is the reversal chamber of flue gas circulation, can be used for again ash deposition.The flapper that is arranged in the ash bucket bottom is regularly opened, and gets rid of the dust stratification in the ash bucket.The metallic surface temperature of crust block formula heating surface is generally 500～600 ℃, and flue gas temperature of hearth outlet is 800～1200 ℃, gaseous state in the high-temperature flue gas or molten metal compound run into the low metal surface meeting condensation of temperature, adhere to simultaneously the thin ash particle in the flue gas, form gradually dust stratification.The design of crust block heating surface is beneficial to and forms the equal dust stratification that distributes, and prevents because thermal resistance is uneven, causes the working medium heat absorption uneven.The arrangement of coarse pitch can effectively reduce fouling of heating surface to the impact of flue gas circulating resistance, reduces the increase of fan energy consumption.

Description of drawings

A kind of boiler flue structural representation that Fig. 1 provides for the utility model.

Fig. 2 arranges schematic diagram (top view) for the U-shaped passage heating surface that the utility model provides.

Crust block formula heating surface front view in the U-shaped passage that Fig. 3 provides for the utility model.

Fig. 4 is the top view of Fig. 3.

Among the figure: 1-the first flue; 2-the second flue; The 3-ash bucket; The 4-flapper; The 5-high temperature reheater; 6-water-cooling wall partition wall; The 7-finishing superheater; The 8-back-end ductwork; The 9-low-temperature reheater; The 10-economizer.

The specific embodiment

Stain serious problem in order to solve the boiler high temperature convection heating surface, the utility model proposes a kind of new boiler flue structural design.Further specify embodiment of the present utility model below in conjunction with accompanying drawing.

A kind of boiler flue structural representation that Fig. 1 provides for the utility model, as shown in Figure 1, described flue comprises the first flue 1, the second flue 2 and back-end ductwork 8.Be water-cooling wall partition wall 6 between the first flue 1 and the second flue 2, the two is communicated with into a U-shaped passage by ash bucket 3, in the first flue 1, arrange high temperature reheater 5, in the second flue 2, arrange finishing superheater 7, arrange low-temperature reheater 9 and economizer 10 in the back-end ductwork 8.The bottom of ash bucket 3 is provided with flapper 4.The high temperature reheater 5 and the finishing superheater 6 that are arranged in the described U-shaped passage all adopt crust block formula structure, coarse pitch arrangement.

During boiler operatiopn, flue gas is flowed through successively and is arranged in high temperature reheater 5 in the first flue 1, is arranged in the finishing superheater 7 in the second flue 2, is arranged in low-temperature reheater 9 and economizer 10 in the back-end ductwork 8.U-shaped channel bottom is provided with ash bucket 3, is the reversal chamber of flow of flue gas, can be used for again the dust stratification deposition.Ash bucket 3 bottoms are provided with flapper 4, regularly open flapper 4, remove the dust stratification in the ash bucket 3.

As shown in Figure 2, the heating surface in the U-shaped passage all adopts the coarse pitch arrangement, to reduce fouling of heating surface to the impact of flow of flue gas resistance, reduces the increase of fan energy consumption.

Shown in Fig. 3 and 4, the heating surface in the U-shaped passage all adopts crust block formula structure, and namely pipe adds the Welding Structure of band steel.During operation, the temperature of crust block formula heating surface is 500～600 ℃, and furnace outlet (separator outlet) flue-gas temperature is 800～1200 ℃.Smoke gas flow is when cold heating surface, and the gaseous state in the flue gas or molten metal compound condense on the tube wall, and tiny can also being adhered to gradually on the tube wall by particle in the flue gas forms dust stratification.Crust block formula heating surface is beneficial to and forms the dust stratification that is evenly distributed, and reduces because the interior working medium heat absorption of the heating surface that the dust stratification skewness causes is uneven.Simultaneously, can also alleviate the dust stratification of heating surface in the back-end ductwork 8.

Suitable adjustment can be carried out according to concrete heating power result of calculation in the size of boiler heating surface, arrangement and installation site when boiler design.This flue structure is not only applicable to pulverized-coal fired boiler, and is applicable to CFBB.

Claims

1. boiler flue structure, it is characterized in that: described flue structure comprises the first flue (1), the second flue (2) and back-end ductwork (8); Be provided with water-cooling wall partition wall (6) between the first flue (1) and the second flue (2), the first flue is communicated with into a U-shaped passage with the second flue by ash bucket (3), and the bottom of ash bucket (3) is provided with flapper (4); In the first flue (1), arrange high temperature reheater (5), in the second flue (2), arrange finishing superheater (7); Arrange low-temperature reheater and economizer in the described back-end ductwork.

2. a kind of boiler flue structure as claimed in claim 1, it is characterized in that: described high temperature reheater (5) and finishing superheater (7) all adopt crust block formula structure, coarse pitch arrangement.