Low-rank coal quality-improving method and equipment

Abstract

The invention relates to a low-rank coal quality-improving method and equipment; according to the method, a coal layer is heated to below 140 DEG C by a first gas heat carrier so as to obtain a water weight content of the dried low-rank coal of 5%-15% and to produce by-product gas; the coal layer temperature of the dried low-rank coal reaches 350-650 DEG C by a second gas heat carrier to obtain dust-containing gas and hot semicoke; the solid-phase substances of the dust-containing gas is separated from gas-phase substances to obtain powdered coal and the gas-phase substances; a part of the gas phase is combusted and supplements the first gas heat carrier or the second gas heat carrier; the other part of the gas phase is cooled to become cracking gas; the hot semicoke and the cracking gas in same space are cooled gradually by a gas cold carrier; heavy components in the cracking gas are precipitated and wrap on the surface of the hot semicoke cooled gradually; the semicoke is cooled by the by-product gas with a temperature of 200-300 DEG C to obtain wrapped semicoke and mixed gas; the cooled wrapped semicoke contacts the by-product gas with a temperature of 40-70 DEG C for water adsorption and surface oxidation and rehydration reaction of the wrapped semicoke so as to obtain a water weight content of the wrapped semicoke of 8-16%.

Description

technical field [0001] The invention relates to a novel low-rank coal upgrading method and equipment thereof, in particular to a low-rank coal upgrading method and equipment coupled with lignite pyrolysis semi-coke passivation and coal tar lightening. Background technique [0002] my country is rich in lignite reserves. In 2010, lignite output exceeded 300 million tons, accounting for 10% of the national coal output. The efficient processing and utilization of lignite has become a highly concerned issue in the field of coal energy in my country. [0003] Due to the short coal-forming period of lignite, its water content, oxygen content and volatile matter are high, and the total water content is as high as 20-60%. On the one hand, it leads to low calorific value, which is not suitable for direct combustion; on the other hand, it causes high chemical reactivity, which is easily weathered and broken in the air, and is not suitable for long-distance transportation and long-ter...

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Problems solved by technology

[0009] 1) Due to the unique properties of coal solid materials, in actual engineering, the formation and control of coal dust (dust) cannot be verified on the scale of laboratories or even semi-industrial test benches;

[0010] 2) The pyrolysis temperature of lignite is low, and various heat exchanges or reactions are relatively low-temperature processes, resulting in small heat transfer temperature differences, difficulty in utilizing low-grade heat, and low process efficiency;

[0011] 3) Research on the mechanism, process operating conditions and engineering scale-up of lignite semi-coke passivation has not yet been carried out, which limits the maturity and commercial promotion of the whole process

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