CN205991505U - A kind of double reheat boiler opposed firing formula flue gas follows system again - Google Patents

Abstract

A flue gas recirculation system with opposite front and rear walls for a secondary reheating boiler. There are mutually symmetrical flue gas recirculation flues on the outer sides of the front and rear walls near the bottom. The flue gas recirculation flues are divided into multiple air intake branches to communicate with the front and rear walls. The exit of each air intake branch Recirculation flue gas nozzles are respectively provided, and the recirculation flue gas nozzles are two rows, and the two rows of recirculation flue gas nozzles are located on the same side of the burner nozzle, one row is higher than the burner nozzle, and the other row is lower than the burner nozzle. nozzle. The utility model achieves the effect of recirculation flue gas hedging combustion by symmetrically setting flue gas recirculation flue and recirculation flue gas nozzle on the front and rear walls of the lower furnace of the boiler, and realizes the full combustion of recirculation flue gas ,Energy saving and environmental protection.

Description

A front and rear wall opposed flue gas recirculation system for a double reheat boiler

Technical field:

The utility model relates to a combustion device for recirculating flue gas of a boiler, in particular to a flue gas recirculation system with front and rear walls facing each other for a secondary reheating boiler.

Background technique:

Existing flue gas recirculation flues of secondary reheating boilers are mostly a single set of flues arranged at the bottom of the main burner, which are only arranged on one side of the furnace, and the recirculation flue gas nozzles in the furnace are one layer, and the There are defects such as excessive unit operation feedback momentum, affecting the shape of the flow field in the furnace, destroying the flow field in the main combustion zone, and small adjustable margin, which cannot fully burn the recirculated flue gas, which not only causes energy loss, but also affects the environment. pollute.

Utility model content:

In order to overcome the above-mentioned shortcomings, the utility model provides a front and rear wall-contrasted flue gas recirculation system for a secondary reheating boiler. The recirculating flue gas nozzle is used to achieve the effect of recirculating flue gas hedging combustion, which realizes the full combustion of recirculating flue gas, energy saving and environmental protection.

The front and rear walls of the utility model for the secondary reheating boiler use a counter-type flue gas recirculation system. The technical solution adopted to achieve the above purpose is: a row of mutually symmetrical columns is vertically arranged in the middle of the front and rear walls of the lower furnace of the boiler. The burner nozzle of the lower furnace of the boiler is equipped with mutually symmetrical flue gas recirculation flues on the outer sides of the front and rear walls near the bottom. There are two rows of recirculation flue gas nozzles at the outlets of each intake branch, and the two rows of recirculation flue gas nozzles are all on the same side of the burner nozzle, and one row is higher than the burner nozzle. Nozzles, another row below the burner nozzles.

As a further improvement of the utility model, a flue gas recirculation fan is provided on the flue gas recirculation flue. With such an arrangement, the recirculating flue gas can quickly enter the furnace body, and the combustion efficiency of the recirculating flue gas can be improved.

As a further improvement of the present utility model, an overburning air nozzle is provided above the burner nozzle in the front and rear walls, and the overburning air nozzle is higher than the recirculation flue gas nozzle. With such an arrangement, air can be supplied to the furnace through the overfired air nozzle, so that the combustion efficiency of the recirculated flue gas can be improved, and the recirculated flue gas can be burned more fully.

As a further improvement of the utility model, each row of recirculation flue gas nozzles is gradually inclined downward from the edge of the front and rear walls to the burner nozzle. Such setting can make the recirculated flue gas sprayed in different spatial positions, make the recirculated flue gas in the furnace more uniform, make the recirculated flue gas fully contact with the burner nozzle, and make the recirculated flue gas Burn more fully.

As a further improvement of the utility model, the recirculation flue is provided with a baffle for adjusting the opening of the recirculation flue.

The beneficial effect of the utility model is that the utility model changes the conventional single set of flue gas recirculation flues into two sets of flue gas recirculation flues by symmetrically setting flue gas recirculation flues on the front and rear walls of the lower furnace of the boiler. Circulating flue, each group of flue gas recirculation flue is divided into two layers of air intake branches connected to the front and rear walls, and the outlet of each air intake branch is provided with recirculation flue gas nozzles, thus forming two rows of recirculation The flue gas nozzles, the recirculated flue gas ejected form the front and rear walls of the opposite shape, which can make the recirculated flue gas distribution in the furnace more uniform, and further adopt a row of recirculated flue gas nozzles higher than the combustion chamber The burner nozzle and another row of recirculation flue gas nozzles are lower than the burner nozzles, so that the recirculation flue gas can be fully burned. Compared with the existing single set of flue gas recirculation flue and single-layer recirculation flue gas nozzles The settings can enhance convective heat transfer, reduce NOx emissions, suppress coking in the furnace, effectively control the temperature of the furnace within a certain range, increase the guaranteed range of low-load steam temperature, reduce the deviation of the flue gas side, and improve the secondary The working conditions of the two-stage high-temperature reheater of the reheat boiler.

Description of drawings:

Fig. 1 is the structural representation of the utility model;

Figure 2 is a schematic diagram of the front wall.

detailed description:

Referring to Fig. 1 and Fig. 2, the double reheating boiler uses the front and rear wall opposed flue gas recirculation system, and the lower furnace of the boiler

A row of mutually symmetrical burner nozzles 1 is arranged vertically in the middle of the front wall 7 and the rear wall 8 of the chamber 9, and mutually symmetrical flue gas recirculation nozzles are arranged on the outer sides of the front and rear walls of the lower furnace near the bottom of the boiler. The flue 2, each flue gas recirculation flue 2 is provided with a flue gas recirculation fan 5 and a baffle, the flue gas recirculation flue 2 is divided into a plurality of intake branches 3 and communicated with the front and rear walls, each The outlets of each intake branch 3 are respectively provided with recirculation flue gas nozzles 4, the recirculation flue gas nozzles 4 are two rows, and the two rows of recirculation flue gas nozzles 4 are all on the same side of the burner nozzle 1, one One row is higher than the burner nozzle 1, and the other row is lower than the burner nozzle 1. There are two recirculation gas nozzles 4 in each row, and the recirculation gas nozzles 4 in each row are from the edge of the front and rear walls to the combustion The nozzle 1 of the burner is gradually inclined downward, and the overfire air nozzle 6 is arranged above the burner nozzle 1 in the front and rear walls, and the overfire air nozzle 6 is higher than the recirculation flue gas nozzle 4 .

work process:

The recirculation flue gas passes through the flue gas recirculation flue 2, passes through each intake branch 3, and is sprayed into the lower furnace 9 of the boiler by the recirculation flue gas nozzle 3, and burns under the action of the burner nozzle 1, and the front and rear walls The flue gas ejected from the recirculating flue gas nozzle 6 forms a hedging effect, which can make the flue gas burn more fully. During the combustion process, the exhaust air nozzle 6 is used to enter the lower furnace 9 of the boiler to improve the combustion efficiency and further Make the flue gas burn fully.

Claims (5)

1. a kind of double reheat boiler opposed firing formula flue gas follow system again it is characterised in that：Boiler lower hearth (9) Forward and backward it is vertically provided with the symmetrical burner nozzle of string (1), the forward and backward wall of boiler lower hearth respectively at middle part within the walls Outside is respectively arranged with symmetrical flue gas recirculation flue (2) near bottom, flue gas recirculation flue (2) be divided into multiple enter Gas branch road (3) is connected with forward and backward wall, and the exit of each air inlet branch road (3) is respectively arranged with flue gas recycled nozzle (4), institute Stating flue gas recycled nozzle (4) is two rows, and two rows' flue gas recycled nozzle (4) are in the same side of burner nozzle (1), one Row is less than burner nozzle (1) higher than burner nozzle (1), another row.

2. as claimed in claim 1 a kind of double reheat boiler opposed firing formula flue gas follow system again it is characterised in that： Described flue gas recirculation flue (2) is provided with gas recirculating fan (5).

3. as claimed in claim 1 a kind of double reheat boiler opposed firing formula flue gas follow system again it is characterised in that： Described forward and backward be provided with burnout degree nozzle (6) in the top of burner nozzle (1) within the walls, described burnout degree nozzle (6) be higher than follow again Ring flue gas nozzle (4).

4. as claimed in claim 1 a kind of double reheat boiler opposed firing formula flue gas follow system again it is characterised in that： The flue gas recycled nozzle (4) of each row is obliquely installed to burner nozzle (1) gradually downward by the edge of forward and backward wall.

5. as claimed in claim 1 a kind of double reheat boiler opposed firing formula flue gas follow system again it is characterised in that： Described recirculating gas duct (2) is provided with baffle plate.