CN1621740A - Curtain wall structure circulating fluidized bed boiler - Google Patents

Abstract

The invention relates to a circulating fluidized bed boiler with a partition wall structure, which can significantly improve the air distribution of the furnace and the combustion conditions inside the furnace, improve the efficiency of the boiler; It solves the problem of uniformity and solves the problem of difficult layout of the heating surface of large-scale CFB boilers. The present invention includes a furnace air distribution plate, a combustion chamber enclosed by the side of the furnace and the furnace roof, and its special feature is that a partition wall is arranged in the dense-phase area of the combustion chamber, and the partition wall can be a partition that runs through the entire combustion chamber as a whole. The wall and the bed surface of the hearth are two parts that are not connected to each other. The partition wall can also be two or more semi-partition walls. The bed surface of the hearth can be a whole, and the upper part of the partition wall is arranged with a heating surface.

Description

Partition wall structure circulating fluidized bed boiler

1. Technical field:

The invention relates to a boiler, in particular to a circulating fluidized bed boiler with a partition wall structure.

2. Background technology:

CFB boiler technology is a world-recognized clean coal combustion technology. It has wide adaptability to coal types, realizes desulfurization and low NOx emissions in the furnace, and has a simple process. It has been widely used in the past two decades and is increasingly large-scale. develop.

Foreign CFB boilers have been developed for a long time and the technology is relatively mature. my country's research and development of large-scale CFB boilers is close to the world level but relatively backward. The production technology of large-scale CFB boilers is almost entirely imported. At present, my country's three major boiler factories: Shanghai Boiler Factory, Dongfang Boiler Factory, and Harbin Boiler Factory have introduced the manufacturing technology of CFB boilers with 135MW and above units from abroad, and have signed production orders for multiple CFB boilers with 300MW units. Due to the wide application market of large-scale CFB boilers in our country, it is a problem that we must face and solve to develop the design and production technology of large-scale CFB boilers with independent intellectual property rights.

The jet flow of the secondary air of the CFB boiler is much smaller than the fluidization momentum of the bed material in the dense phase zone, and the range of the secondary air is quite limited, causing an obvious anoxic area in the center of the furnace, and with the increase in the cross-sectional area of the furnace Increase (mainly the furnace depth increases) the more serious the lack of oxygen in the center of the furnace, which seriously affects the combustion of fuel in the furnace. Therefore, in the process of enlarging CFB boilers, the lack of oxygen in the central area of the furnace is a problem that must be solved.

The height and furnace wall area of CFB boilers do not increase proportionally with the increase of capacity. The height of the CFB boiler is generally limited within a certain range, and the depth of the furnace is affected by the penetration ability of the secondary air, so it cannot be set too large. Therefore, after the CFB boiler is enlarged, the size of the furnace expands greatly in the width direction, which greatly increases the manufacturing cost. Since the increase in furnace wall area does not increase proportionally with the increase in capacity, the layout of the heating surface of the boiler after the CFB boiler is enlarged is also a problem that must be solved.

In the large-scale process of CFB boilers, several major foreign CFB boiler companies mostly combine furnaces with successful operation experience to form large-scale furnaces.

The CFB boiler of the 250MW unit in Provence, France is formed by the combination of two CFB boilers of the 125MW unit. The bottom of the furnace is a double-leg structure, with two bed surfaces, and the furnace is divided into two parts. The double-leg structure design at the bottom of the furnace ensures proper velocity distribution and bed material particle size concentration distribution on different cross-sections in the lower part of the combustion chamber, and ensures effective and deep mixing of the secondary air. The 300MW unit CFB boiler of Qinhuangdao Power Plant introduced in my country and the 300WM unit CFB boiler introduced by Baima all use this type of furnace.

The lower part of the furnace of the double-legged CFB boiler is completely separated, and the bed materials in the two different areas cannot be well circulated, and the combustion imbalance in the two beds may occur during operation; The combustion imbalance intensifies and the combustion condition deteriorates.

3. Contents of the invention:

In order to solve the deficiencies in the above-mentioned background technology, the present invention provides a circulating fluidized bed boiler with a partition wall structure, which can significantly improve the air distribution of the furnace and the combustion conditions inside the furnace, and improve the efficiency of the boiler; and solve the problems in the operation process. The problem of uneven pressure on the two bed surfaces of the double-leg structure and the problem of difficult layout of the heating surface of large-scale CFB boilers are solved.

To achieve the above object, the technical solution adopted in the present invention is:

A circulating fluidized bed boiler with a partition wall structure, including a furnace air distribution plate, a combustion chamber surrounded by the side of the furnace and the furnace roof, and its special feature is that a partition wall is arranged in the dense phase area of the combustion chamber.

The above-mentioned partition wall can be a partition wall that runs through the entire combustion chamber as a whole, and the bed surface of the furnace is two parts that are not connected to each other.

The above-mentioned partition wall can be two or more half partition walls, and the bed surface of the hearth can be a whole.

The shape of the partition wall can be truncated or pyramidal, cuboid, spherical, or partially ellipsoidal.

The upper part of the partition wall is arranged with a heating surface, and the height of the heating surface is the full furnace height in the furnace height direction, the full furnace width or part of the furnace width in the furnace width direction, and the full furnace depth or partial furnace depth in the depth direction.

The above-mentioned partition walls are symmetrically arranged in the furnace and on the bed surface along the center line of the furnace, and the dense-phase area of the furnace combustion chamber forms a saddle-shaped area, or in a staggered arrangement in the furnace and on the bed surface, and the dense-phase area of the furnace combustion chamber forms a Zigzag area.

The heating surface on the upper part of the partition wall can be a light pipe or a membrane wall; the metal tube on the heating surface on the upper part of the partition wall can be bifurcated, and the bottom of the partition wall is provided with a contact surface.

Air outlets are arranged on the side and top of the partition wall.

A bottom slag outlet is arranged on the side of the partition wall.

Compared with prior art, the advantages and effects that the present invention has are as follows:

1. The present invention can well solve the problem of lack of oxygen in the center of a large-scale CFB boiler by supplying air to the central area of the furnace, and improves the combustion status of the boiler. The solution to the furnace air supply problem and the improvement of the fuel and oxygen mixing conditions can provide greater flexibility in the selection of the furnace structure, so that the selection of the CFB boiler structure can get rid of the restriction of the furnace width and depth ratio (mainly due to the secondary air The lack of penetration ability leads to the selection of furnace depth must be within a certain range).

2. The integral bed surface on the upper part of the air distribution plate of the present invention can make the operation of the boiler more balanced and stable, and can effectively solve the problem of unbalanced operation of the double bed surface caused by the disconnection of the two legs of the double-leg CFB boiler .

3. The present invention arranges the heating surface on the upper part of the partition wall inside the furnace, which can arrange the arrangement of the heating surface more conveniently, and effectively solves the problem of difficulty in arranging the heating surface of the furnace.

4. Description of drawings:

Fig. 1 is a schematic diagram of the layout of the combustion chamber and the partition wall of the present invention.

Fig. 2 is a schematic diagram of another layout of the combustion chamber and the partition wall of the present invention.

Fig. 3 is a schematic diagram of the bottom structure of the combustion chamber of the present invention.

5. Specific implementation methods:

Referring to Fig. 1, Fig. 2, Fig. 3, the present invention comprises the combustion chamber 1 surrounded by the furnace air distribution plate 3 and the furnace side and the furnace roof 2, and the partition wall 4 is arranged at the bottom of the combustion chamber 1, the sides and end faces of the partition wall 4 Arrange tuyere 5 above and above, provide combustion-supporting air (comprising air or oxygen-enriched air) to combustion chamber; The side of partition wall, end face and above also can arrange bottom slag outlet 6, realize discharging slag here.

Referring to Fig. 1, the partition wall 4 can run through the entire combustion chamber 1 as a whole. Referring to Fig. 2, the partition wall 4 can be divided into two or more sections, arranged in a staggered manner at the bottom of the combustion chamber 1, or adopt other structural forms to make the bottom of the combustion chamber 1 The bed surface becomes a whole. The shape of the partition wall 4 can be prism, pyramid, cuboid, spherical crown, part ellipsoid or other shapes; The phase area forms a saddle-shaped area, and can also be arranged in a staggered row in the furnace and on the bed surface, and the dense-phase area of the furnace combustion chamber forms a zigzag area; Arrangement of the heating surface, the height of the heating surface 7 is the full furnace height in the furnace height direction, or the partial furnace height, and the full furnace width or partial furnace width in the furnace width direction; the full furnace depth in the depth direction or non-full furnace depth; the heating surface 7 can be a bare tube or a membrane wall; the metal tube on the heating surface at the top of the partition wall 4 can be bifurcated or not; the bottom of the partition wall 4 can have a contact surface, There may also be no contact surface; the bottom of the partition wall 4 extending into the furnace may be in contact with the air distribution plate 3, or the lower part of the partition wall 4 is not arranged with the air distribution plate 3; it may also be in a suspended state without contact with the air distribution plate 3; The end faces of the partition wall 4 extending into the furnace can be in contact with the four walls of the furnace, or not in contact with the four walls of the furnace.

Claims (9)

1, a kind of curtain wall structure circulating fluidized bed boiler comprises the combustion chamber (1) that burner hearth air distribution plate (3) and burner hearth side and furnace roof (2) surround, and it is characterized in that: be furnished with partition wall (4) in the emulsion zone of described combustion chamber (1).

2, curtain wall structure circulating fluidized bed boiler according to claim 1 is characterized in that: described partition wall (4) runs through one partition wall of whole combustion chamber (1) for integral body, and the bed surface of burner hearth is not connected two parts.

3, curtain wall structure circulating fluidized bed boiler according to claim 1 is characterized in that: described partition wall (4) is two or more half partition walls, and the bed surface of burner hearth is as a whole.

4, according to claim 2 or 3 described curtain wall structure circulating fluidized bed boilers, it is characterized in that: described partition wall (4) be shaped as terrace with edge shape or pyramid, cuboid, spherical, part elliposoidal.

5, curtain wall structure circulating fluidized bed boiler according to claim 4, it is characterized in that: heating surface (7) is arranged on the top of described partition wall (4), the height of heating surface (7) is full furnace height in the furnace height direction, width at burner hearth is full furnace width or partial hearth width, is the full furnace depth or the partial hearth degree of depth at depth direction.

6, curtain wall structure circulating fluidized bed boiler according to claim 5, it is characterized in that: described partition wall (4) is symmetric figure with bed surface upper edge burner hearth center line and arranges in burner hearth, fire box's emulsion zone forms the saddle type zone, or in burner hearth and on the bed surface, be mistake and arrange and put, fire box's emulsion zone forms the zigzag zone.

7, curtain wall structure circulating fluidized bed boiler according to claim 6, it is characterized in that: the heating surface (7) on described partition wall (4) top is light pipe or membrane wall, heating surface (7) metal tube bifurcated on partition wall (4) top is provided with, and partition wall (4) bottom is provided with contact-making surface.

8, curtain wall structure circulating fluidized bed boiler according to claim 7 is characterized in that: the side of described partition wall (4) and above be furnished with air port (5).

9, curtain wall structure circulating fluidized bed boiler according to claim 8 is characterized in that: the side arrangement of described partition wall has end slag slag notch (6).

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