Fluidized-bed low-rank coal upgrading utilization system and method

Abstract

The invention provides a fluidized-bed low-rank coal upgrading utilization system and method, and belongs to the technical field of low-rank coal upgrading utilization. According to the invention, a washing system, a pyrolysis system and an iron-making system of the low-rank coal are coupled together. Firstly, the low-rank coal is subjected to washing treatment so that size grading of the coal is completed while waste stone is exhausted. The coal powder different in particle size is used for a coking system to prepare coke and joins in medium and low temperature pyrolysis to prepare semicoke. The semicoke obtained through pyrolysis is used as coal for sintering and blended coal for injection, respectively; the by-product gas of pyrolysis is fed into a hot blast stove for combustion, wherein waste heat generated by the sintering and coking process systems is recovered for the washing system and the pyrolysis system; and finally, the sinter, the hot air, the injection coal and the coke are fed into a blast furnace for iron-making. According to the invention, the separation, grading, drying and pyrolysis of the low-rank coal are realized; the low-rank coal is utilized after being upgraded in stead of partial high-rank coal; and therefore, the cost of iron per ton can be effectively reduced and the stress of the demand of the iron and steel industry for the high-rank coal can be reduced.

Description

technical field [0001] The invention relates to a low-rank coal quality upgrading and product utilization process system, in particular to a system and method for utilizing low-rank coal sorting, grading, drying and dry distillation upgraded products for sintering, coking and blast furnace processes in the iron and steel industry. Background technique [0002] my country's energy structure is rich in coal, poor in oil, and low in gas, and its coal reserves rank third in the world after the United States and Russia. According to the data provided by the National Bureau of Statistics, my country's mineable coal reserves have reached 114.828 billion tons, and low-rank coal accounts for about 45%. The efficient processing and utilization of low-rank coal has become a hot issue in the field of coal energy research in my country. [0003] Because low-rank coal has the characteristics of high moisture content, high oxygen content, easy weathering and spontaneous combustion, low cal...

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Problems solved by technology

[0005] Chinese invention patent (application number: 201210527862.0) discloses a low-rank coal multi-stage fluidized bed coal chemical polygeneration system and its method, the low-rank coal is sent to the circulating fluidized bed boiler for combustion after drying and carbonization, but In this patent, only the low-rank coal is considered to be sent to the fluidized bed boiler for combustion after upgrading, but the coal particles are not sorted and graded. Use according to quality, because the composition of coal quality will also change to varying degrees with the change of particle size

[0006] Chinese invention patent (Application No.: 200910153522.4) discloses a circulating fluidized bed coal graded conversion coal gas tar semi-coke polygeneration device and method, the device closely combines the circulating fluidized bed gasifier and the fluidized bed carbonization furnace, Realize the joint production of gas, tar and semi-coke, but the energy consumption to maintain the system operation is high, and the high-temperature process in the system mainly targets high-rank coal

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