Device and method for grading lignite by granularity and drying lignite

Abstract

The invention discloses a device and a method for grading lignite by granularity and drying the lignite. The device comprises a grading subsystem, a fine grain drying subsystem, a coarse grain drying subsystem and an exhausting subsystem, wherein the grading subsystem is connected with the fine grain subsystem, and the grading subsystem is connected with the coarse grain drying subsystem; and the exhausting subsystem is connected with the fine grain drying subsystem, and the exhausting subsystem is connected with the coarse grain drying subsystem. According to the device and the method, the original lignite is graded by granularity first and then dried separately, so the quality of the product is improved; the configuration of the device is easy to optimize, the cost of the device is low, and the drying efficiency of the device is high; waste gas afterheat can be recycled in the drying device, the device has high energy efficiency, a small amount of exhaust gas is required to be treated, and the treatment cost is low; and the drying device is very safe, and the installation, operation and maintenance of the device are very convenient, and the cost of the device is low.

Description

technical field [0001] The invention relates to a low-rank coal upgrading device and method, in particular to a lignite drying device and method for grading high-moisture lignite according to particle size and then drying them separately. Background technique [0002] As a typical low-rank coal, lignite has a moisture content ranging from 15% to 70% (the moisture content of lignite in my country is generally between 30% and 40%). Too high moisture brings many problems to the utilization of lignite, such as: (1) high moisture leads to lower calorific value and system energy efficiency; (2) high moisture makes coal grindability worse, coal powder quality decreases, and hinders sorting (3) High moisture will adversely affect various chemical applications; (4) High moisture will greatly increase transportation volume and transportation costs, and it will also cause coal piles to freeze in cold winter or cold regions . [0003] Drying is the most effective way to reduce the moi...

AI Technical Summary

Problems solved by technology

However, the tube bundle dryer has high requirements for manufacturing process and operation control, and there is still a considerable gap in this aspect in China, and the investment cost of the entire drying system is very expensive, far exceeding the current economic bearing capacity of our country.

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