Equipment and process for lignite fluidized bed drying and upgrading

Abstract

The invention relates to a device for drying and upgrading a lignite fluidized bed and a technology of the device. At present, the same type of device which is high in drying efficiency and high in environment friendliness and a technology of the device do not exist. The device for drying and upgrading the lignite fluidized bed is characterized by comprising a ring hammer type crusher, a cyclone separator, a lignite molding machine, a finished product storehouse, a lignite granule pipe, a lignite powder backflow pipe, a lignite granule conveying belt and a powder-steam conveying pipe, wherein one end of the lignite powder backflow pipe is connected to the bottom of the cyclone separator, and the other end of the lignite powder backflow pipe is connected to the lignite granule pipe; the lignite molding machine and the finished product storehouse are connected with each other through the belt. The technology disclosed by the invention comprises the following steps that (1) raw lignite is conveyed into the ring hammer type crusher for crushing, and the crushed lignite is conveyed into the lignite storehouse through the conveying belt; (2) overheated steam is input into a fluidized bed dryer through an overheated steam pipe; (3) the separated lignite powder is discharged from the bottom of the cyclone separator; (4) the lignite powder is molded under compression of the lignite molding machine to obtain finished lignite products. The device and the technology are high in drying efficiency and high in environment friendliness, and the steam can be recycled.

Description

technical field [0001] The invention relates to a lignite drying and upgrading device and its process, in particular to a lignite fluidized bed drying and upgrading device and its process, belonging to the field of lignite drying and upgrading. Background technique [0002] my country has abundant coal resources, among which lignite reserves account for about 15% of the total coal reserves. However, due to the following characteristics of lignite, it brings certain difficulties to industrial application. [0003] (1) The calorific value is low. The calorific value of lignite is generally around 3000 kcal, which is significantly lower than the standard of 4600 kcal for low-quality coal stipulated for industrial applications. [0004] (2) High water content, the water content of lignite is generally above 30%. [0005] (3) Well-developed pores, low density, easy weathering, easy spontaneous combustion, not conducive to storage. [0006] (4) High volatile content. The volati...

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Problems solved by technology

[0005] (3) Developed pores, low density, easy weathering, easy spontaneous combustion, not conducive to storage

[0006] (4) High volatile content, the volatile content of lignite generally exceeds the standard stipulated for power coal, which is not conducive to the stable combustion of the furnace

The traditional lignite drying process mostly adopts the drum drying method, the drying medium is high-temperature flue gas, and the drying efficiency is low

Due to the high volatile content of lignite, it is easy to catch fire and explode during the drying process, and the safety is poor

In addition, in the drum drying process, a large amount of dust is generated, which is poor in environmental protection

The fluidized bed dryer uses superheated steam as the drying medium, which has the advantages of high drying efficiency, good safety and environmental protection. However, the dried lignite still exists due to the pore structure, and there is a phenomenon of reabsorption of water, which affects the sales radius of the lignite.

[0008] There are also some other lignite drying methods now, as disclosed on April 24, 2013, in the Chinese patent whose publication number is CN103060039A, a lignite drying molding process is disclosed, the lignite drying molding process comprises raw material lignite through drying, After crushing and extruding to obtain shaped particles, the raw lignite is sent to the tube dryer for indirect heat exchange with the drying medium, and the water content of the dried lignite is controlled to be 8-12Wt%; the dried lignite is sent to the crusher Crushed until the particle size is <3mm; the crushed lignite is fed into the roll forming machine, the linear pressure of the roller is 120-140kN / cm, the pit type is long row pit roller + smooth roller, and the online speed is 850-1000r / h. The length of the roller is 400-800mm, and it is extruded into shaped particles with a particle size ≥ 15mm; the lignite drying and molding process is difficult to effectively destroy the pore structure of the lignite, resulting in re-absorption of water in the lignite after drying, and it is difficult to truly reduce the moisture content of the lignite Rate

Another example is that the publication date is April 17, 2013, and the publication number is CN103045321A Chinese patent, which discloses a method for drying and upgrading lignite. After entering the screening and crushing device, it is crushed and screened; the crushed lignite enters the jet crushing dryer for primary drying, and the dried coal powder is collected by the cyclone; the primary dried coal powder is transported to the Tubular dryer performs secondary drying; the pulverized coal that has completed the secondary drying and upgrading is directly transported into the forming equipment pad to press the formed coal and then transported to the mesh belt for cooling. This method of drying and upgrading lignite is also difficult to effectively destroy the pore structure of lignite , resulting in re-absorption of water in the dried lignite, making it difficult to truly reduce the moisture content of the lignite

[0009] To sum up, there is no lignite fluidized bed drying and upgrading device with high drying efficiency, good environmental protection, steam recycling, effective destruction of lignite pore structure, and effective prevention of lignite after drying. its craft

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