Device and method for drying lignite in a combined mode through microwave and hot air

Abstract

The invention discloses a device and a method for drying lignite in a combined mode through microwave and hot air, and belongs to the technical field of lignite drying equipment. The device comprisesa feeding device, a vibration transmission mechanism, a hot air generating device, microwave generating devices, a drying cavity, a temperature measuring system and a tail gas treatment device, wherein the feeding device comprises a feeding hopper and a spiral feeder, the hot air generating device comprises a blower and a hot blast stove; more than one microwave generating device and more than oneexhaust port are arranged above the drying cavity; a heat preservation layer and a metal shell capable of shielding microwaves are arranged in the cavity, the vibration transmission mechanism is connected with a vibration motor outside a cavity, and the tail end of the vibration transmission mechanism is provided with a drawable baffle and a discharge port. The method for drying lignite in a combined mode through microwave and hot air comprises the following steps of crushing raw coal, and carrying out the sieving treatment; carrying out the feeding through the spiral feeder, starting the hotair generating device and the microwave generating device; carrying out the vibration and conveying through the vibration transmission mechanism, drying the brown coal in the microwave drying cavitythrough microwave hot air, and obtaining a finished product through drying, and collecting the finished product in the finished product coal bin through a movable baffle. The device is simple in structure, low in investment cost, small in occupied area, high in operation efficiency and capable of realizing continuous production; the method for drying in a combined mode through the microwave and the hot air is capable of improving the heat efficiency of materials and high in drying speed, capable of recycling waste heat, high in energy utilization rate, capable of reducing energy consumption, and environment-friendly.

Description

technical field [0001] The invention belongs to the field of lignite drying, and in particular relates to a device and method for drying lignite combined with microwave hot air. Background technique [0002] Lignite belongs to low-quality coal. Due to the well-developed pores and surfaces, it has strong water absorption and high moisture content (20-50%). Due to its own defects such as large combustion smoke, low calorific value, easy weathering and spontaneous combustion, it is not convenient for storage and transportation, which limits its effective transformation and utilization to a large extent, and seriously restricts its economic benefits and competitiveness. In order to cleanly and efficiently utilize lignite resources and reduce utilization costs, dehydration and upgrading of lignite before combustion is an essential step. [0003] At present, the conventional lignite drying methods at home and abroad are mainly fluidized bed or rotary drying methods, which general...

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Problems solved by technology

[0003] At present, the conventional lignite drying methods at home and abroad are mainly fluidized bed or rotary drying methods, which generally have the following disadvantages: ①It can only remove the external moisture of lignite, and it is not easy to dry the internal water and capillary water, and the dried product is prone to moisture resorption; ② It is easy to ignite pulverized coal accidents, and there is a risk of burning or even explosion; ③The drying equipment has a complex structure, consumes a lot of energy, occupies a large area, and the equipment cost is high; ④The moisture content of lignite powder and lumps is uneven, and the drying is uneven

However, the process of this patent method is complicated, the equipment occupies a large area, and the process of hot air is implanted twice, which leads to high energy consumption and high industrial cost.

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