Fume dried lignite medium speed mill powder-making system

Abstract

The invention discloses a fume dried lignite medium speed mill powder-making system. According to the system, a drying device is connected with a coal inlet at the top part of a medium speed mill; a coal inlet and a high temperature fume drying agent inlet are arranged at the top part of the drying device; a coal outlet is arranged at the bottom of the drying device; an exhaust port is arranged at a side plane of the bottom of the drying device; the exhaust port is connected with an air inlet of the medium speed mill through a powder exhauster; a rough powder separator is connected with a fine powder separator; a coal outlet of the fine powder separator is connected with a powder feeder; the powder feeder is connected with an air-powder mixer; one way of hot air of an air pre-heater is connected with the air-powder mixer through a primary air box; an exhaust exit of the fine powder separator is connected with a dust collector; a powder outlet of the dust collector is further connected with the powder feeder; and an air outlet of the dust collector is connected with the exhaust exit. With the adoption of the system, the use of a medium speed mill powder-making system in a combustion high moisture lignite unit becomes possible; the blending combustion of lignite of a large ratio or complete lignite combustion in a fuel coal unit which adopts a straight-blowing medium speed mill powder-making system can be realized; the efficiency of the unit is further increased and the coal consumption in power generation is reduced; and meanwhile the system has the advantages that the detonation is not caused, the operation is safe and the moisture in the lignite can be recycled.

Description

technical field [0001] The invention belongs to the technical field of coal-fired power generation, and relates to lignite power generation technology. Specifically, it relates to a pulverizing system and a combustion system of a coal-fired power station boiler. Background technique [0002] Lignite is the mineral coal with the lowest degree of coalification. It is the initial product of peat deposition that is dehydrated and compacted into organic biorock. It is named for its brown or dark brown appearance. Lignite accounts for about 18% of my country's thermal coal reserves, mainly distributed in Inner Mongolia, the three northeastern provinces and Yunnan. Lignite has a high volatile content (V daf >37%), high moisture (total moisture is about 30%, external moisture mostly exceeds 19%), low calorific value (about 12.56MJ / kg), low ash melting point (about 1150°C), low abrasiveness (HGI is 50-70) and easy spontaneous combustion and other characteristics. The character...

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Problems solved by technology

[0010] The technical problem to be solved by the present invention is to provide a medium-speed pulverization system for flue gas drying lignite, which solves the problem of low pulverization efficiency due to insufficient drying output of medium-speed pulverizers when grinding high-moisture lignite , causing problems such as insufficient boiler output and poor combustion performance of pulverized coal; and using inert medium as the desiccant and pulverized medium in the medium-speed coal mill, the safety of the pulverizing system is significantly enhanced; at the same time, it also reduces coal consumption for power generation and recovers large amount of water

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