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Operation regulating method for preventing furnace coking after boiler trip (BT) of supercritical circulating fluidized bed boiler

A circulating fluidized bed and supercritical technology, which is applied to fluidized bed combustion equipment, combustion methods, fuels burned in a molten state, etc., can solve problems such as boiler and unit commissioning failure, improper treatment measures, and improper operation. To achieve the effect of ensuring safe operation and normal production, good guidance and practical value, and avoiding economic losses

Active Publication Date: 2020-11-06
DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

During the restart process of the boiler after BT, due to operational errors and improper handling measures, coking accidents occurred many times, resulting in the failure of the boiler and unit to be put into operation
[0004] Baima 600MW supercritical CFB boiler is the first CBF boiler with the largest capacity and supercritical parameters put into operation. During the startup and trial operation of the boiler, many boiler BT accidents occurred. Improper operation resulted in severe coking in the furnace, which resulted in damage to the furnace hood and falling off of the water-cooled wall pouring material

Method used

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  • Operation regulating method for preventing furnace coking after boiler trip (BT) of supercritical circulating fluidized bed boiler

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Example 1: The first domestic 600MW supercritical circulating fluidized bed boiler BT was restarted to deal with the "furnace coking" accident.

[0043] In the early stage of the first 600MW supercritical circulating fluidized bed boiler in China, there were many boiler BTs. During the subsequent hot restart process of the boiler, a large area of ​​high-temperature coking accident occurred in the furnace, which caused the furnace hood The damage and the pouring material of the water wall fell off, causing serious economic losses to the power plant.

[0044] According to the analysis of the accident, the main reasons were improper adjustment and control of key parameters such as boiler primary fluidization air volume, coal feeding timing and size, bed temperature rise rate, inaccurate accident prediction, and untimely initial treatment of the accident.

[0045]After switching to the operation control method provided by this patent, key operating parameters such as primar...

Embodiment 2

[0046] Example 2: A 330MW circulating fluidized bed boiler BT in China was restarted to deal with the "furnace coking" accident.

[0047] After a 330MW circulating fluidized bed boiler in China was improved for efficiency improvement, during the restart process, due to the failure of auxiliary equipment, the boiler BT was caused. During the subsequent hot restart process of the boiler, a high-temperature coking accident occurred in the furnace, which led to The damage of the air cap in the furnace and the deformation of the panel heating surface caused serious economic losses to the power plant.

[0048] According to the analysis of the accident, the main reasons were improper adjustment and control of key parameters such as boiler primary fluidization air volume, coal feeding timing and size, bed temperature rise rate, inaccurate accident prediction, and untimely initial treatment of the accident.

[0049] After communicating with the power plant, after the operating personne...

Embodiment 3

[0050] Example 3: The world's first 660MW supercritical circulating fluidized bed boiler started trial operation.

[0051] The first 660MW supercritical circulating fluidized bed boiler is the supercritical CFB boiler with the largest capacity in the world that will be put into operation after the domestic 600MW boiler. In the initial stage of trial operation of the boiler, due to equipment and power grid reasons, it is very likely that Boiler BT accidents, the technical solution of the present invention can be adopted, and the successful experience of domestic 600MW supercritical CFB boilers in dealing with "BT restart furnace coking" can be used to effectively avoid the occurrence of "BT restart furnace coking" accidents, creating a smooth operation for boiler units. Good technical condition.

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Abstract

The invention discloses an operation regulating method for preventing furnace coking after a boiler trip (BT) of a supercritical circulating fluidized bed boiler. The operation regulating method comprises the following steps: S1, bed temperature of the boiler is higher than 650 DEG C; S2, a fan is started; S3 primary fluidizing air flow is increased to make temperature rise of middle / lower layer bed temperature of a furnace stable; S4, the primary fluidizing air flow is gradually reduced; S5, a coal feeder is immediately started to perform coal feeding; S6, whether the change of the middle / lower bed temperature of a dense-phase zone of the furnace with the coal quantity and fluidizing air flow, and the differential pressure of the furnace are normal or not is judged, and if normal, S7 is executed, otherwise S10 is executed; S7, whether the boiler is overheated or not is judged, and if the boiler is overheated, S8 is executed, otherwise S9 is executed; S8, high-pressure and low-pressurebypasses of a steam turbine are opened wide; S9, the boiler and a unit operate normally; and S10, coal feeding is stopped or the coal feeding rate is reduced, then, pulse-type purging is performed, and the boiler is shut down if improvements fail. The operation regulating method can effectively avoid the problems that restarting failure of the boiler and the unit accident shutdown are caused by furnace coking caused by explosive burning of stacked fuel in the boiler in the restarting process after the BT of the supercritical circulating fluidized bed (CFB) boiler to cause rapid sharp rising of the bed temperature.

Description

technical field [0001] The invention relates to the technical field of circulating fluidized bed boilers, in particular to an operation control method for preventing coking in a furnace after a BT of a supercritical circulating fluidized bed boiler. Background technique [0002] The main direction of the development of circulating fluidized bed (CFB) boilers is large-scale and ultra-supercritical parameters. At present, CFB boilers with 350MW and 600MW grades of supercritical parameters have been put into commercial operation in China, and then larger capacity and ultra-supercritical parameters (Shanxi Pingshuo 660MW, Guizhou Weihe 660MW) CFB boilers will also be put into commercial operation. [0003] The 300MW subcritical CFB boiler put into operation in the early stage and the 600MW and 350MW supercritical CFB boilers currently put into operation, due to various reasons such as unit equipment, power grid, and human operation, the boiler BT (accident shutdown) was caused. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F23C10/28F23C10/20
CPCF23C10/28F23C10/20
Inventor 郑兴胜郭强吴朝刚李果李维成周棋苏虎巩李明薛燕辉
Owner DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP