System for pre-drying coal with high water content by utilizing residual heat of boiler gas

Abstract

The invention relates to a system for pre-drying coals with high water content by utilizing residual heat of boiler gas. The system comprises a boiler, a gas pre-processing system, a raw coal pre-drying system and a desulfurizing system that are sequentially connected with one another by gas pipelines; the system also comprises a raw coal pre-processing machine and a coal pulverizer; the raw coal pre-processing system is connected with a raw coal pre-drying system by a coal conveying pipeline; the coal pulverizer is connected with the raw coal pre-drying system and the boiler respectively by the coal conveying pipelines; and furthermore, the coal pulverizer is also connected with the gas pre-processing system by the gas pipeline. In the invention, the boiler smoke is used as a drying medium of the coal with high water content; part of water in the coal is removed before the coal is pulverized so that the coal quality is improved, the drying treatment requirement of the powdering system is reduced, the dimension of the boiler and a blowing system can be reduced, the manufacturing cost can be reduced, and the heat efficiency of the boiler system can be improved by about 2%.

Description

technical field [0001] The invention relates to a method and an implementation system for pre-drying high-moisture coal by using boiler flue gas waste heat, and belongs to the technical field of boiler waste heat utilization and energy saving and emission reduction. Background technique [0002] Coal is currently the main fuel for power production in China, and high-moisture coal (such as lignite) occupies a large share in my country's coal resource composition. Moisture in some coals can even reach 30-40% by weight. The high moisture in the raw coal causes the boiler flue gas system to use higher temperature primary air to the coal mill to dry the coal, resulting in a high temperature of the flue gas entering the air preheater, and high moisture in the flue gas also leads to air The high exhaust gas temperature of the preheater reduces the overall efficiency of the boiler. After the moisture in the raw coal evaporates, all of it enters the furnace, resulting in the size o...

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Problems solved by technology

[0004] (1) The system is complex, and it is necessary to set up a high-temperature fume extraction system to reduce the heat utilization efficiency of the flue gas

[0005] (2) The exhausted flue gas and the moisture evaporated from the coal all enter the furnace of the boiler, which increases the size of the furnace and the size of the boiler, and the cost of the boiler is high

[0006] (3) The amount of flue gas discharged from the boiler is large, resulting in a large power consumption of the fan

[0007] (4) The ventilation volume in the coal mill is large, so the coal mill needs to use a larger size

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