A lignite drying waste heat and water recovery system

Abstract

The invention discloses a lignite drying waste heat and water recovery system, wherein the raw coal enters the drier through a coal feeder, the moisture in the raw coal is vaporized after absorbing heat in the drier, the raw coal becomes dry coal, and the exhaust gas of the drier enters the bag for dust removal The separated coal powder enters the coal mill together with the dry coal for grinding through the powder falling pipe; the exhaust gas at the outlet of the bag filter enters the condensing heat exchanger, and in the condensing heat exchanger, it is mixed with the circulating cooling water After the heat exchange is completed, the recovered water is output from the condensing heat exchanger for utilization. The heated circulating cooling water enters the primary and secondary air heaters through the pipeline, and the cold air is mixed with the heated air in the primary and secondary air heaters. The circulating cooling water performs heat exchange, the cold air is heated, and then enters the air preheater in the boiler flue to be heated again into hot primary and secondary air; the circulating cooling water after heat release returns to the condensing heat exchanger again to absorb heat, forming The complete closed-loop system realizes waste heat and water recovery of the dryer at the same time.

Description

Technical field: [0001] The invention belongs to the field of waste heat recovery and application of dry lignite, and in particular relates to a system for recovering waste heat and water from lignite drying. Background technique: [0002] In the existing power plant boilers that use the dry lignite produced by the lignite pre-drying system, when the dry exhaust gas moisture is recovered through the condensation heat exchanger, the heat of the exhaust gas can be recovered and utilized except that the condensed water is used as the cooling medium. When circulating water is used as the cooling medium, it is usually cooled by air-cooled islands. The heat of the circulating water is lost in a large amount and is not used reasonably, which causes a lot of energy waste. [0003] In order to improve the economical efficiency of the unit in the lignite pre-drying system and further reduce the energy consumption of the unit while saving water, it is necessary to develop a new heat re...

AI Technical Summary

Problems solved by technology

[0002] In the existing power plant boilers that use the dry lignite produced by the lignite pre-drying system, when the dry exhaust gas moisture is recovered through the condensation heat exchanger, the heat of the exhaust gas can be recovered and utilized except that the condensed water is used as the cooling medium. When circulating water is used as the cooling medium, air-cooled island cooling is often used, and the heat of circulating water is lost in a large amount without being rationally utilized, which causes a lot of energy waste

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