CN-122015108-A - Coal-fired boiler small powder bin island coal powder storage and supply system and operation method

CN122015108ACN 122015108 ACN122015108 ACN 122015108ACN-122015108-A

Abstract

The invention discloses a coal-fired boiler small powder bin island coal powder storage and supply system and an operation method thereof, and relates to the technical field of coal-fired power generation. The system comprises a closed small powder bin island, a coal grinding unit, a raw coal powder channel communicated with the coal grinding unit and the burner, and a powder storage channel and a powder supply channel which are independently arranged outside the boiler plant. The small powder bin island is internally provided with a small powder bin, a coal powder conveying device, a waste gas treatment system and a ventilation device for maintaining the micro-positive pressure of 40-100Pa in the island. The method comprises three modes of basic load direct blowing, load-reducing powder storage and load-lifting powder supply, and the flexible switching of the pulverized coal between the direct blowing mode and the storage mode is realized by controlling the valve and the start-stop conveying device. The invention solves the problems of space, load and construction period of old factory reconstruction through the modularized independent island design, obviously reduces the explosion risk through the cooperation of micro positive pressure and exhaust negative pressure, and greatly improves the peak regulation rate and response flexibility of the unit through flexible operation of 'system-storage-use'.

Inventors

WANG YI
DENG WEI
WU TENG
XU KAI
XU JUN
JIANG LONG
SU SHENG
HU SONG
XIANG JUN

Assignees

华中科技大学

Dates

Publication Date: 20260512
Application Date: 20260209

Claims (10)

1. The pulverized coal storage and supply system of the small powder bin island of the coal-fired boiler is characterized by comprising the small powder bin island (300) which is arranged independently of a boiler plant; The coal grinding unit comprises at least one coal mill, and the coal mill is connected with the burner (6) through a raw coal powder channel; At least one small powder bin is arranged in the small powder bin island (300), a powder inlet of the small powder bin is communicated with a coal mill through a powder storage channel, and a powder outlet of the small powder bin is communicated with a combustor (6) through a powder supply channel; The small powder bin island (300) is also provided with an intra-island ventilation device for maintaining a positive pressure environment of 40Pa to 100Pa in the small powder bin island (300).
2. The small powder bin island coal powder storage and supply system of a coal-fired boiler according to claim 1, wherein the small powder bin island (300) is a sealed bin, and the in-island ventilation device comprises a ventilation fan (319) communicated with the small powder bin island (300) and a grid ventilation opening (320) arranged on the side wall of the small powder bin island (300).
3. The small powder bin island pulverized coal storage and supply system of a coal-fired boiler according to claim 2, wherein a first control valve is arranged on the powder storage channel, and a second control valve is arranged on the raw coal powder channel.
4. The small powder bin island pulverized coal storage and supply system of a coal-fired boiler according to claim 1, wherein a first-stage separator and a second-stage separator are sequentially arranged on the powder storage channel, and a waste gas outlet is arranged on the second-stage separator.
5. The small powder bin island pulverized coal storage and supply system of a coal-fired boiler according to claim 4, further comprising a spent gas treatment system, wherein the spent gas treatment system comprises a spent gas fan (317) and a spent gas burner (318), an inlet of the spent gas fan (317) is connected with a spent gas outlet of the second-stage separator, and an outlet of the spent gas fan (317) is connected with the spent gas burner (318).
6. The small powder bin island pulverized coal storage and supply system of the coal-fired boiler according to claim 1, wherein a pulverized coal conveying device for conveying pulverized coal stored in the small powder bin to the burner (6) is arranged on the powder supply channel.
7. The small powder bin island coal powder storage and supply system of a coal-fired boiler according to claim 6, wherein the coal powder conveying device comprises a power mechanism and a coal feeder communicated with a small powder bin, and an outlet of the power mechanism is converged with an outlet of the coal feeder through a wind-powder mixer and communicated with a combustor (6).
8. The small powder bin island pulverized coal storage and supply system of a coal-fired boiler according to claim 7, wherein the power mechanism is a roots blower (301) or a branch pipeline leading from a primary blower (5) of the coal grinding unit.
9. A method of operation for a pulverized coal storage system as claimed in any one of claims 1 to 8, comprising the following modes of operation: The basic load operation mode is to close a first control valve on the powder storage channel and open a second control valve on the raw coal powder channel, so that all coal powder generated by the coal mill is directly conveyed to the burner (6) through the raw coal powder channel; The load-reducing powder storage mode is to open the first control valve while keeping the second control valve open, so that the pulverized coal part generated by the coal mill is split through a powder storage channel and is stored in a corresponding small powder bin after being separated by the first-stage separator and the second-stage separator; and in the load-lifting powder supply mode, the second control valve is kept open, and meanwhile, the pulverized coal conveying device is started to convey pulverized coal stored in the small powder bin to the burner (6) through the powder supply channel.
10. The method of claim 9, wherein in the load-shedding powder storage operation mode, pulverized coal separated from a powder storage channel sequentially passes through a first-stage separator and a second-stage separator for classification separation before entering a small powder bin, and the exhaust gas separated by the second-stage separator is sucked by an exhaust gas fan (317) and sent to an exhaust gas combustor (318); in the load-lifting powder supply operation mode, the specific process of starting the pulverized coal conveying device is that a power mechanism is started, a coal feeder corresponding to a target small powder bin is started, stored pulverized coal is mixed with conveying wind, and then the mixed pulverized coal is output through a powder supply channel.

Description

Coal-fired boiler small powder bin island coal powder storage and supply system and operation method Technical Field The invention relates to the technical field of coal-fired power generation, in particular to a coal-fired boiler small powder bin island coal powder storage and supply system for improving peak regulation flexibility of a coal-fired power generation unit and an operation method. Background New energy sources represented by wind energy and solar energy are integrated into a power grid on a large scale, but the power generation of the new energy sources has volatility and intermittency, so that the load stability of the power grid is challenging. The coal-fired power generating unit is a key flexible resource for realizing large-scale and economic deep rapid peak shaving at present. Thus, the flexibility of the active coal-fired unit, particularly the load response rate thereof, becomes an urgent requirement for safe and stable operation of the power grid. The core difficulty in improving the flexibility of coal-fired boilers is the response delay of the coal-feeding and pulverizing systems. By additionally arranging the small powder bin between the coal mill and the burner, redundant coal powder can be stored when the unit is in load reduction, and the stored coal powder can be quickly released when the load is increased, so that the load lifting speed of the unit is obviously improved. However, such modifications to an old power plant that has been commissioned present a significant challenge: 1. The space limitation is that the old factory is compact in design, and the factory is lack of enough space to install the newly-added small powder bin and the accessory equipment thereof. 2. Structural load-newly added heavy equipment on the original factory building structure may exceed the bearing capacity of the heavy equipment, and complex structural detection and reinforcement are required. 3. And during the reconstruction, part of units need to maintain operation, construction and production areas are crossed, the safety risk is high, and noise and dust are easy to interfere with operation equipment. 4. Construction period is intense-the grid typically provides only a very short outage service window (e.g., about 30 days), and construction period is very strenuous. 5. Safety risk is that when the high-volatile coal powder is stored, the small powder bin system has the risk that combustible gas is separated out and explosion is initiated. In order to solve the problems, a technical scheme which can not only effectively improve the flexibility of the unit, but also adapt to severe conditions of factory transformation and has high safety is needed. Disclosure of Invention The invention aims to solve the technical problem of providing the coal powder storage and supply system and the operation method which can effectively improve the peak regulation flexibility of the coal-fired unit, adapt to severe conditions such as reconstruction space, load, construction period and the like of old factories and have high safety. The technical scheme for solving the technical problems is as follows: a coal-fired boiler small powder bin island coal powder storage and supply system comprises a small powder bin island which is arranged independently of a boiler plant; The coal grinding unit comprises at least one coal mill, and the coal mill is connected with the burner through a raw coal powder channel; At least one small powder bin is arranged in the small powder bin island, a powder inlet of the small powder bin is communicated with the coal mill through a powder storage channel, and a powder outlet of the small powder bin is communicated with the combustor through a powder supply channel; the small powder bin island is also provided with an intra-island ventilation device for maintaining a positive pressure environment of 40Pa to 100Pa in the small powder bin island. The invention has the beneficial effects that by arranging the independent small powder bin island, the powder storage, powder supply and related auxiliary systems are externally arranged, thus not only fundamentally solving the problems of insufficient factory building space, limited load of the original structure and mutual interference of construction and operation in the transformation of the old machine set, but also needing no large-scale structural reinforcement of the original factory building, greatly shortening the construction period; Meanwhile, the ventilation device in the island ensures that the micro-positive pressure environment of 40Pa-100Pa is always maintained in the island of the small powder bin, external air infiltration can be effectively prevented, combustible gas possibly separated out of equipment (such as the small powder bin) in the island is pumped out by the ventilation pipeline under negative pressure, combustible volatile matters possibly separated out of the small powder bin are ensured to be directionally pumped