Method and equipment for drying lignite particles and pulverized coal granules

Abstract

The invention discloses a method and equipment for drying lignite particles and pulverized coal granules. The method comprises the steps of: screening and crushing lignite raw materials with the grain size over 50mm into granules with the grain sizes of 4mm-50mm, and lignite raw materials with the grain size less than 4mm into granules with the grain size of 4mm-12mm, and feeding the particles into a pressure container to be sealed; filling low-pressure high-temperature superheated steam into the pressure container to exchange heat with the lignite particles, stopping supplying the superheated steam when the lignite particle temperature reaches 130 DEG C-290 DEG C or the inside pressure of the pressure container is higher than 1.5 megapascals, and starting stabilizing the pressure; and taking the modified lignite which is heated by superheated steam out after stabilizing the pressure for 10 minutes, and stacking and cooling under natural conditions. The superheated steam is taken as a heating medium, so that the lignite particles are modified to have the characteristics tending to bituminous coal. The pressure container effectively ensure that the lignite particles are dried at the optimum temperature and pressure and timely discharges waste gases and condensed water, so that the water content of the dried lignite particles is obviously reduced, very small back absorption is generated, spontaneous igniting and weathering are not generated, and the unit heating value is greatly increased.

Description

technical field [0001] The invention relates to the field of coal processing and utilization, in particular to lignite particles and drying technology after granulation of pulverized coal. Background technique [0002] Over the years, a large number of researches and experiments have been done at home and abroad on the technical process of reducing the moisture content of lignite and improving coal quality. There are many kinds of methods used, but there is no mature technical process, and there are many disadvantages, mainly: ①. The coal after drying is still It completely has the disadvantages of lignite, which is prone to spontaneous combustion, weathering, and easy to absorb water and return to moisture. ②. Due to the low ignition point of lignite during dry drying, the danger of hot air drying is high, and it is easy to catch fire or even explode; the degree of environmental pollution control is poor, and wet (steam) drying is performed with fluidized bed drying, and th...

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Problems solved by technology

[0002] Over the years, a large number of researches and experiments have been done at home and abroad on the technical process of reducing the moisture content of lignite and improving coal quality. There are many kinds of methods used, but there is no mature technical process, and there are many disadvantages, mainly: ①. The coal after drying is still It completely has the disadvantages of lignite, which is prone to spontaneous combustion, weathering, and easy to absorb water and return to moisture

②. Due to the low ignition point of lignite during dry drying, the danger of hot air drying is high, and it is easy to catch fire or even explode; the degree of environmental pollution control is poor, and wet (steam) drying is performed with fluidized bed drying, and the amount of steam is large. High energy consumption, high production cost, and expensive equipment

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