CN214147866U

CN214147866U - System is reformed transform to circulating fluidized bed boiler

Info

Publication number: CN214147866U
Application number: CN202022930507.0U
Authority: CN
Inventors: 李军虎; 张俊国; 李一博; 何龙
Original assignee: Xi'an Huadian Clean Energy Technology Co Ltd
Current assignee: Xi'an Huadian Clean Energy Technology Co Ltd
Priority date: 2020-12-08
Filing date: 2020-12-08
Publication date: 2021-09-07
Anticipated expiration: 2030-12-08

Abstract

The utility model discloses a circulating fluidized bed boiler reforms transform system, the top export of circulating fluidized bed boiler furnace is linked together with the entry of separator, the top export of separator and boiler afterbody flue, the bottom export of separator is linked together with the entry of feed back valve, the first export of feed back valve is linked together with the ash return mouth of circulating fluidized bed boiler furnace, the second export of feed back valve is linked together with circulating ash discharge system, the front wall department, back wall department and the side wall department of circulating fluidized bed boiler furnace all are provided with slag removal system; the air distribution plate is arranged on the hearth of the circulating fluidized bed boiler, and the lug bosses are arranged on the air distribution plate, so that the low-load operation bed temperature of the boiler can be effectively improved, and the slag discharge capacity of the boiler is improved.

Description

System is reformed transform to circulating fluidized bed boiler

Technical Field

The utility model belongs to the technical field of clean coal power generation, a circulating fluidized bed boiler reforms transform system is related to.

Background

Under the situation of rapid development of renewable energy sources, the demand of the adjustable capacity of the power system is increased sharply based on the characteristic of intermittent power generation of clean energy sources. The conventional thermal power generating unit is required to bear the peak shaving obligation of the whole power system besides providing the stable power supply function. In recent years, while the renewable energy is rapidly developed, serious phenomena of wind abandoning and light abandoning occur, and the problem of consumption of the renewable energy becomes a key factor for restricting the development of the renewable energy.

In order to comply with the national policy of new energy consumption and enhance the competitiveness of CFB units, the CFB units in China also need low-load stable combustion deep peak regulation transformation, and the stable operation of the CFB units under 30% load is ensured. However, it is known that, when some units are operated at low load after deep peak shaving modification, the combustion condition in the furnace becomes very complex, the fluidization condition is poor, field technicians are not familiar with unit operation evaluation, performance conditions and state quantities to be monitored under deep peak shaving, and need to tightly look at the unit operation condition all the time, so that manual operation is implemented, the workload of operators is large, and meanwhile, great hidden danger is brought to unit safety. The reasons for this are that the boiler has poor fluidization quality of the air distribution plate under low load, low temperature of the operating bed and weak slag discharge capability.

Chinese patent application CN111023086A discloses a method for adapting a subcritical circulating fluidized bed boiler to grid deep peak shaving. According to the method, during the peak period of new energy power generation, the boiler is fired, the load of a steam turbine is reduced to 3-8 MW, service power and auxiliary steam are carried by another turbine, the unit is guaranteed not to be disconnected from the network and operate at low load for 2-3 hours, the requirement of the power grid during the valley peak regulation period is met, and meanwhile, deep peak regulation compensation can be obtained to meet the requirement of the power plant for profitability. The method needs to stop the boiler by pressing fire, and realizes the deep peak regulation of the power grid. The method does not relate to how to flexibly modify the boiler, and realizes deep peak regulation.

Chinese patent application CN111359414A discloses a CFB boiler deep peak shaving composite type adjustable SNCR denitration system and a method. The method discloses a CFB boiler deep peak-shaving composite type adjustable SNCR denitration system and method, and mainly relates to how to carry out denitration when the load of a deep peak-shaving boiler is about 20%, so that ultralow emission is realized. The method also does not relate to how to flexibly modify the boiler, and realizes deep peak regulation.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome above-mentioned prior art's shortcoming, provide a circulating fluidized bed boiler system of reforming transform, this system can effectual improvement boiler low-load operation bed temperature, improves the sediment ability of boiler simultaneously.

In order to achieve the purpose, the utility model discloses a circulating fluidized bed boiler transformation system comprises a circulating fluidized bed boiler furnace, a separator, a feed back valve, a boiler tail flue, a circulating ash discharge system and a slag discharge system;

the top outlet of the circulating fluidized bed boiler furnace is communicated with the inlet of the separator, the top outlet of the separator is communicated with the flue at the tail part of the boiler, the bottom outlet of the separator is communicated with the inlet of the material return valve, the first outlet of the material return valve is communicated with the ash return port of the circulating fluidized bed boiler furnace, the second outlet of the material return valve is communicated with the circulating ash discharge system, and the front wall, the rear wall and the side wall of the circulating fluidized bed boiler furnace are respectively provided with a slag discharge system;

an air distribution plate is arranged on the circulating fluidized bed boiler furnace, and a boss is arranged on the air distribution plate.

A lower secondary air port is arranged on a hearth of the circulating fluidized bed boiler, the relative distance H between the lower secondary air port and the air distribution plate is 2.5-3.5 m, and the inclination angle alpha of the lower secondary air port is 15-30 degrees.

A water-cooled wall, a water-cooled screen, a screen superheater and a screen reheater are arranged in the hearth of the circulating fluidized bed boiler.

The slag discharging system comprises a slag inlet pipe section, wherein a blast cap is arranged in an area of 0-0.4 m of an inlet section of the slag inlet pipe section.

The boss consists of a fireproof wear-resistant material and a pin, wherein the pin is fixed on a water conveying pipe and a ribbed plate of the water wall.

The wind cap is a directional wind cap, a mushroom-type wind cap or a bell-type wind cap.

The boss is a boss with a trapezoidal cross section, a boss with a special-shaped cross section or a boss with a rectangular cross section.

The utility model discloses following beneficial effect has:

circulating fluidized bed boiler reform transform system when concrete operation, front wall department, back wall department and side wall department at circulating fluidized bed boiler are provided with slag discharging system to in the import section region of slag inlet pipe section design hood, with the sediment ability of improving the boiler, simultaneously, the second export intercommunication of feed back valve has circulation ash discharge system, with the circulation ash volume in the reduction boiler, improve the operation bed temperature under the boiler low-load then, convenient operation, simple, the practicality is extremely strong.

Further, the relative distance H between the lower secondary air port and the air distribution plate is 2.5-3.5 m, the inclination angle alpha of the lower secondary air port is 15-30 degrees, the secondary air feeding position is higher, the cooling effect on a bed layer is weakened, the operating bed temperature of the boiler under low load is improved, and finally the lowest stable combustion load is favorably reduced.

Drawings

Fig. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic structural view of the air distribution plate of the present invention;

FIG. 3 is a layout view of the boss on the air distribution plate of the present invention;

FIG. 4 is a view showing a structure of a boss on the air distribution plate of the present invention;

FIG. 5a is a cross-sectional view of a boss;

FIG. 5b is a view of another cross-sectional shape of the boss;

FIG. 5c is a view of another cross-sectional shape of the boss;

FIG. 6 is a schematic view of the blast cap added to the middle slag inlet pipe section of the present invention.

Wherein, 1 is a circulating fluidized bed boiler hearth, 2 is a separator, 3 is a feed back valve, 4 is a boiler tail flue, 5 is a circulating ash discharge system, 6 is a slag discharge system, 11 is an air distribution plate, 12 is a lower secondary air port, 13 is an upper secondary air port, 14 is a water wall, 15 is a water screen, 16 is a screen superheater, 17 is a screen reheater, 61 is a slag inlet pipe section, 62 is an air cap, 63 is a slag discharge port, 71 is a refractory wear-resistant material, 72 is a pin, 73 is a water conveying pipe, and 74 is a rib plate.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings:

referring to fig. 1 to 6, the system for reforming a circulating fluidized bed boiler according to the present invention includes a furnace 1 of the circulating fluidized bed boiler, a separator 2, a material return valve 3, a tail flue 4 of the boiler, a circulating ash discharge system 5 and a slag discharge system 6; the top outlet of the circulating fluidized bed boiler furnace 1 is communicated with the inlet of the separator 2, the top outlet of the separator 2 is communicated with the boiler tail flue 4, the bottom outlet of the separator 2 is communicated with the inlet of the material return valve 3, the first outlet of the material return valve 3 is communicated with the ash return port of the circulating fluidized bed boiler furnace 1, the second outlet of the material return valve 3 is communicated with the circulating ash discharge system 5, and the front wall, the rear wall and the side wall of the circulating fluidized bed boiler furnace 1 are respectively provided with a slag discharge system 6; the circulating fluidized bed boiler furnace 1 is provided with an air distribution plate 11, the air distribution plate 11 is provided with a boss 70, the slag discharging system 6 comprises a slag inlet pipe section 61 and subsequent slag conveying equipment, and the circulating fluidized bed boiler furnace 1 is provided with the air distribution plate 11, a lower secondary air port 12 and an upper secondary air port 13.

In actual operation, the air distribution plate 11 is provided with the bosses 70, and the number of the bosses 70 is one or more, so that the area of the air distribution plate 11 is reduced, the structure of the air cap is optimized or the resistance of the air cap is increased, the air distribution uniformity of the air distribution plate 11 is improved, and the critical fluidization air quantity is reduced. In addition, the elevation of the lower secondary tuyere 12 (namely, the relative distance H between the lower secondary tuyere 12 and the air distribution plate 11 is increased) can be improved, and the angle alpha and the air quantity of the lower secondary tuyere 12 can be reduced, so that the operating bed temperature of the boiler under low load can be improved.

The circulating fluidized bed boiler 1 is internally provided with a water wall 14, a water screen 15, a screen superheater 16 and a screen reheater 17, and during actual operation, the passing heating area or heat transfer coefficient can be reduced, so that the operating bed temperature of the boiler under low load can be further improved.

And simultaneously, the utility model discloses be provided with slag removal system 6 in circulating fluidized bed boiler furnace 1's front wall department, back wall department and side wall department, advance and be provided with hood 62 in the 0 ~ 0.4m region of induction zone of sediment pipeline section 61 to improve the sediment ability of boiler, the form of hood is bell jar formula hood.

It needs to explain finally, the utility model discloses be provided with circulation ash discharge system in the second export of feed back valve to reduce the circulation ash volume in the boiler, improve the operation bed temperature under the boiler low-load then, convenient operation, simple, the practicality is extremely strong.

Claims

1. A reforming system of a circulating fluidized bed boiler is characterized by comprising a circulating fluidized bed boiler hearth (1), a separator (2), a material return valve (3), a boiler tail flue (4), a circulating ash discharge system (5) and a slag discharge system (6);

the top outlet of the circulating fluidized bed boiler furnace (1) is communicated with the inlet of the separator (2), the top outlet of the separator (2) is communicated with the boiler tail flue (4), the bottom outlet of the separator (2) is communicated with the inlet of the material return valve (3), the first outlet of the material return valve (3) is communicated with the ash return port of the circulating fluidized bed boiler furnace (1), the second outlet of the material return valve (3) is communicated with the circulating ash discharge system (5), and the front wall, the rear wall and the side wall of the circulating fluidized bed boiler furnace (1) are respectively provided with a slag discharge system (6);

an air distribution plate (11) is arranged on the circulating fluidized bed boiler furnace (1), and a boss (70) is arranged on the air distribution plate (11).

2. The system for reforming the circulating fluidized bed boiler according to claim 1, wherein a lower secondary tuyere (12) is arranged on the hearth (1) of the circulating fluidized bed boiler, the relative distance H between the lower secondary tuyere (12) and the air distribution plate (11) is 2.5-3.5 m, and the inclination angle alpha of the lower secondary tuyere (12) is 15-30 degrees.

3. A circulating fluidized bed boiler reforming system according to claim 1, characterized in that a water wall (14), a water screen (15), a screen superheater (16) and a screen reheater (17) are arranged in the circulating fluidized bed boiler furnace (1).

4. The system of claim 1, wherein the slag tapping system (6) comprises a slag inlet pipe section (61), and wherein a hood (62) is arranged in an area of 0-0.4 m of an inlet section of the slag inlet pipe section (61).

5. A system for reforming a circulating fluidized bed boiler according to claim 1, wherein the boss (70) is composed of a refractory and wear-resistant material (71) and a pin (72), wherein the pin (72) is fixed on a water conveying pipe (73) and a rib plate (74) of the water wall (14).

6. A circulating fluidized bed boiler reforming system according to claim 4, characterized in that the hood (62) is a directional hood, a mushroom-type hood or a bell-type hood.

7. A circulating fluidized bed boiler reforming system according to claim 1, wherein the boss (70) is a boss having a trapezoidal cross section, a boss having a special-shaped cross section, or a boss having a rectangular cross section.