Device for recycling water and utilizing waste heat in exhaust air after lignite is dried

Abstract

The invention discloses a device for recycling water and utilizing waste heat in exhaust air after lignite is dried. The device comprises two parallel heating cavities and a heat exchange cavity between the two heating cavities. The side wall of each heating cavity is provided with an exhaust air inlet and an exhaust hole, and the bottom of each heating cavity is provided with a drain hole. A feeding inlet is formed in the top of the heat exchange cavity, and a discharge opening is formed in the bottom of the heat exchange cavity. By means of the device for recycling the water and utilizing the waste heat in the exhaust air after the lignite is dried, the heat recycled from the dried exhaust air can be used for heating original lignite before the original lignite enters a drying device, the temperature of the original lignite is raised to reduce heat consumption in the drying device, and system economy is remarkable. The device is not provided with any moving device, so that device maintenance and overhaul cost is low. Besides, disturbance and influences on the lignite are small. Moreover, the device can be modularly generated, the processing capacity of the device can be improved by increasing the number of the heating cavities and the heat exchange cavity, and the amount of recycled water and heat can be controlled conveniently through the amount of coal.

Description

Technical field: [0001] The invention belongs to the technical field of lignite drying and upgrading, and in particular relates to a device for recovering water in exhausted gas after lignite drying and utilizing waste heat. Background technique: [0002] Lignite is the mineral coal with the lowest degree of coalification, which has the characteristics of high moisture (30%-60%), high volatile matter, and low calorific value. my country has proven lignite reserves of 130 billion tons, accounting for 13% of the country's coal reserves, and lignite is mainly used for direct combustion power generation in my country's power industry. Generally, lignite boilers generally have problems such as large flue gas volume and high exhaust temperature, resulting in bulky boilers, generally low efficiency, and difficulty in large-scale units. [0003] With the implementation of my country's "Energy Development Strategic Action Plan (2014-2020)" and the promulgation of the country's "Inte...

AI Technical Summary

Problems solved by technology

The exhaust gas after lignite drying carries a large amount of latent heat of vaporization absorbed by the evaporation of water in the coal. Direct emptying will cause a lot of waste of heat and affect the economy of the entire drying system.

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