CN218914900U - Differential pressure driven flue gas recirculation adjusts reheat steam temperature system - Google Patents

Abstract

The utility model provides a flue gas recirculation adjusts reheat steam temperature system of differential pressure drive, includes boiler, desulfurizing tower, flue gas circulation pipeline between, and the boiler lower part is the furnace combustion zone, is equipped with partition screen superheater, screen formula reheat ware, high temperature superheater, low temperature superheater, economizer, air heater, dust remover, draught fan in boiler top and the play flue gas pipeline, and draught fan rear portion pipeline is connected with the desulfurizing tower; the low-temperature clean flue gas extraction point is arranged on a pipeline between the induced draft fan and the desulfurizing tower, the low-temperature clean flue gas access point is arranged at the bottom of the boiler, the low-temperature clean flue gas extraction point is connected with the low-temperature clean flue gas access point through a smoke return pipeline, and the smoke return pipeline is provided with a pneumatic shutoff door I and an electric regulating door. According to the utility model, through the structure, the low-temperature clean flue gas recirculation amount is controlled by adjusting the opening of the electric adjusting door of the flue gas recirculation pipeline, so that the purpose of improving the reheat steam temperature of the boiler under low load is achieved.

Description

Differential pressure driven flue gas recirculation adjusts reheat steam temperature system

Technical Field

The utility model belongs to the technical field of thermal power generation, and particularly relates to a differential pressure driven flue gas recirculation reheating steam temperature regulating system.

Background

With the social development, the installed capacity ratio of new energy sources such as wind power, photovoltaic, hydropower and the like is greatly improved. In consideration of the remarkable uncertainty, volatility and periodicity characteristics of new energy power generation and the current development situation, in order to improve the power consumption capacity of the new energy of the power grid, the pulverized coal boiler of the power station tends to continue to participate in deep peak shaving of the power grid, which means that the boiler is kept to operate under a low-load working condition for a long time.

At present, most of pulverized coal boilers in power stations cannot burn designed coal types, and when actual burning coal types deviate greatly, the economical efficiency and the safety of the boiler operation can be greatly influenced. When the deep peak regulation of the power grid is participated, the boiler needs to be kept to run under a low-load working condition for a long time, the boiler deviates from the original design working condition, the heat absorption condition of heating surfaces of all levels of the boiler changes, one of the more problems is that the reheat steam temperature is too low to meet the steam temperature requirement of a steam turbine, and the long-term running in the state can seriously influence the safety and the service life of a unit.

When the pulverized coal boiler of the power station participates in deep peak regulation of the power grid, the proportion of the radiation heat exchange amount and the convection heat exchange amount in the whole combustion process is changed due to the fact that the proportion deviates from the original design working condition to a large extent, the temperature of reheat steam is possibly too low, and the temperature of the reheat steam cannot reach the target by adopting a combustion adjustment means of a tangential boiler or a hedging boiler. In addition, the heating surfaces of all stages of the pulverized coal boiler of the existing power station are arranged in a compact mode, and the implementation of a modification scheme for increasing the area of the heating surfaces is greatly limited.

Disclosure of Invention

The utility model provides a pressure difference driven system for regulating reheat steam temperature by recycling flue gas, which aims to solve the problem of lower reheat steam temperature during deep peak regulation of a pulverized coal boiler of a power station and has the characteristics of simple structure, low investment and good regulating effect.

In order to solve the technical problems, the utility model adopts the following technical scheme:

the utility model provides a flue gas recirculation adjusts reheat steam temperature system of differential pressure drive, includes boiler, desulfurizing tower, flue gas circulation pipeline between, and the boiler lower part is the furnace combustion zone, is equipped with partition screen superheater, screen formula reheat ware, high temperature superheater, low temperature superheater, economizer, air heater, dust remover, draught fan in boiler top and the play flue gas pipeline, and draught fan rear portion pipeline is connected with the desulfurizing tower; the low-temperature clean flue gas extraction point is arranged on a pipeline between the induced draft fan and the desulfurizing tower, the low-temperature clean flue gas access point is arranged at the bottom of the boiler, the low-temperature clean flue gas extraction point is connected with the low-temperature clean flue gas access point through a smoke return pipeline, and the smoke return pipeline is provided with a pneumatic shutoff door I and an electric regulating door.

The smoke return pipeline is provided with a pneumatic shutoff door II, and the electric regulating door is arranged between the pneumatic shutoff door I and the pneumatic shutoff door II and is used for regulating the proportion of low-temperature clean smoke at the tail part of the extraction boiler.

The inner wall of the upper part of the boiler is provided with a wall type reheater, the bottom of the boiler is provided with a slag dragging machine, and a slag discharging hole is arranged between a smoke return pipeline and a low-temperature clean smoke access point.

Drawings

Fig. 1 is a schematic view of the inventive structure.

Detailed Description

The following description of the embodiments of the present utility model will be made with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model disclosed herein without departing from the scope of the utility model.

A pressure difference driven flue gas recirculation adjusting reheat steam temperature system comprises a boiler, a desulfurizing tower 20 and flue gas circulation pipelines between the boiler and the desulfurizing tower. The lower part of the boiler is a hearth combustion zone 3, a partition screen superheater 5, a screen superheater 6, a screen reheater 7, a high-temperature reheater 8, a high-temperature superheater 9, a low-temperature superheater 10, an economizer 11, an air preheater 12, a dust remover 13 and an induced draft fan 14 are arranged in a flue gas outlet pipeline at the top of the boiler, and a pipeline at the rear part of the induced draft fan 14 is connected with a desulfurizing tower 20; the low-temperature clean flue gas extraction point 1 is arranged on a pipeline between the induced draft fan 14 and the desulfurizing tower 20, the low-temperature clean flue gas access point 2 is arranged at the bottom of the boiler, the low-temperature clean flue gas extraction point 1 is connected with the low-temperature clean flue gas access point 2 through a smoke return pipeline, and the smoke return pipeline is provided with a pneumatic shutoff door I15 and an electric regulating door 16. A chimney 21 is arranged behind the desulfurizing tower 20 for exhausting smoke. The low-temperature clean flue gas extraction point 1 is positioned between the outlet of the induced draft fan and the inlet of the desulfurization system, and the low-temperature clean flue gas access point 2 is positioned below the burner area and at the bottom of the hearth.

The smoke return pipeline is provided with a pneumatic shutoff door II17, and the electric regulating door 16 is arranged between the pneumatic shutoff door I15 and the pneumatic shutoff door II 17. The inner wall of the upper part of the boiler is provided with a wall type reheater 4, the bottom of the boiler is provided with a slag scooper 19, and a slag discharging hole 18 is arranged between a smoke return pipeline and the low-temperature clean smoke access point 2.

The specific use is as follows:

1, a smoke recycling smoke return pipeline is arranged, and an electric regulating door 16 is arranged on the smoke return pipeline and used for regulating the recycling smoke amount so as to achieve the aim of improving the reheat steam temperature under low load;

2, determining extraction values: carrying out a boiler combustion optimization adjustment test under low load, combining a boiler original design reheat steam temperature adjustment mode with a flue gas recirculation amount adjustment mode, confirming an extraction value of recirculated flue gas according to a reheat steam temperature lifting effect under low load, obtaining a comprehensive adjustment mode of reheat steam temperature under low load, and determining a ratio of low-temperature clean flue gas extraction amount to total boiler tail flue gas;

and 3, when the depth of the pulverized coal boiler of the power station is in peak regulation, the low-temperature clean flue gas at the tail of the boiler in the proportion obtained in the step 2 is extracted by utilizing differential pressure driving and adjusting an electric regulating door 16, and is conveyed to the bottom area of the hearth.

The utility model utilizes differential pressure to drive, extracts the tail smoke of the boiler with the proportion not higher than 20 percent and conveys the tail smoke to the bottom area of the hearth. The flue gas enters the hearth to participate in combustion, so that the reaction temperature in the hearth is reduced, the radiation heat exchange quantity of a water cooling wall of a radiation heating surface of the hearth, a wall type reheater 4, a partition screen superheater 5, a half radiation heating surface screen superheater 6 and a screen type reheater 7 is reduced, the flue gas quantity is increased, the total heat capacity of the flue gas is increased, the convection heat quantity of a high-temperature reheater 8, a high-temperature superheater 9, a low-temperature superheater 10 and an economizer 11 of a corresponding boiler horizontal flue convection heating surface is increased, the low-temperature clean flue gas recirculation quantity is controlled by adjusting the opening of an electric control door of a flue gas recirculation pipeline, and the aim of improving the reheat steam temperature of the boiler under low load is fulfilled.

Claims (3)

1. The utility model provides a flue gas recirculation of differential pressure drive adjusts reheat steam temperature system, includes boiler, desulfurizing tower (20), flue gas circulation pipeline between, its characterized in that: the lower part of the boiler is a hearth combustion zone (3), a partition screen superheater (5), a screen superheater (6), a screen reheater (7), a high-temperature reheater (8), a high-temperature superheater (9), a low-temperature superheater (10), an economizer (11), an air preheater (12), a dust remover (13) and an induced draft fan (14) are arranged at the top of the boiler and in a smoke outlet pipeline, and the rear pipeline of the induced draft fan (14) is connected with a desulfurizing tower (20); the low-temperature clean flue gas extraction device is characterized in that a low-temperature clean flue gas extraction point (1) is arranged on a pipeline between the induced draft fan (14) and the desulfurizing tower (20), a low-temperature clean flue gas access point (2) is arranged at the bottom of the boiler, the low-temperature clean flue gas extraction point (1) is connected with the low-temperature clean flue gas access point (2) through a smoke return pipeline, and a pneumatic shutoff door I (15) and an electric regulating door (16) are arranged on the smoke return pipeline.

2. A differential pressure driven flue gas recirculation conditioning reheat steam temperature system as defined in claim 1, wherein: the smoke return pipeline is provided with a pneumatic shutoff door II (17), and the electric regulating door (16) is arranged between the pneumatic shutoff door I (15) and the pneumatic shutoff door II (17).

3. A differential pressure driven flue gas recirculation conditioning reheat steam temperature system as defined in claim 1, wherein: the inner wall of the upper part of the boiler is provided with a wall type reheater (4), the bottom of the boiler is provided with a slag dragging machine (19), and a slag discharging hole (18) is arranged between a smoke return pipeline and the low-temperature clean smoke access point (2).

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