Comprehensive utilization system and method for lignite upgrading and drying energy

Abstract

The invention discloses a comprehensive utilization system and method for lignite upgrading and drying energy. According to the system, a fume outlet of a hot blast stove (8) is connected with a fly ash separator (9); an ash residue outlet at the lower end of the fly ash separator (9) is connected with a high-temperature ash cooler (7); a clean fume outlet is connected with a dry wind inlet of a fluidized bed dryer (1); a fume outlet of the fluidized bed dryer (1) is connected with a cyclone separator (10); and a material outlet of the fluidized bed dryer (10) is sequentially connected with an inlet of a finished product coal temperature reduction device (6), and an inlet of a lignite screen separation device (12). The system makes the best of the heat generated during fine pulverized-coal combustion after the completion of lignite drying to dry the lignite, without an external heat; the heat pump technology is adopted to recover the exhaust heat generated by ready coal, high-temperature ash residue, exhaust steam and the like during the lignite drying process for predrying of the lignite; and meanwhile, the ash residue and solidified water are adopted to form ash residue slurry for industrial brick manufacturing raw materials, so as to achieve the purposes of energy conservation, emission reduction and waste utilization.

Description

technical field [0001] The invention relates to the field of upgrading and drying lignite, in particular to an energy recovery system and method for lignite drying. The system does not need an external heat source, and introduces heat pump technology to make full use of and recover the low-grade heat in the lignite upgrading process, and is especially suitable for upgrading and drying lignite with high moisture content. Background technique [0002] Among the proven lignite reserves in China, the northeastern region of Inner Mongolia is the largest, accounting for about 3 / 4 of the national lignite reserves. And the lignite in the central and southern regions only accounts for about 5% of the country's total. Lignite is a kind of coal with the lowest degree of coalification. Lignite has high porosity and strong reactivity. The oxygen content in coal is about 15% to 30%, most of which exist in the form of oxygen-containing functional groups. carbonyl group. The moisture con...

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Problems solved by technology

[0004] At present, most of the existing lignite drying technologies have high energy consumption and lack of waste heat recovery and utilization devices (such as: CN102965168A, CN102175030B, CN102759260A, CN101260307A), and most of the lignite drying comprehensive utilization systems are very complicated and difficult to realize (such as: CN102925243A, CN202242579U , CN200975664Y); even some mature processes use hot flue gas generated by gas to dry lignite, high-grade heat energy consumes a lot of energy and has low utilization rate

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