A lignite drying method and drying equipment utilizing power plant flue gas and steam waste heat

Abstract

The invention discloses a brown coal drying method and device utilizing waste heat of smoke and steam of a power plant. The drying method comprises two-time drying treatment, wherein the two-time drying treatment comprises the steps that firstly, the high-temperature smoke directly discharged by a power plant coal fired boiler is utilized for conducting first-time drying treatment on damp materials, the high-temperature smoke directly makes uniform contact with the damp materials, and intermediate materials are obtained; and secondly, the high-temperature smoke and the high-temperature steam directly discharged by the power plant coal fired boiler are utilized for conducting second-time drying treatment on the intermediate materials at the same time, the high-temperature smoke directly makes uniform contact with the intermediate materials, meanwhile, the intermediate materials make uniform contact with a heat exchange pipe inflated with the steam for heat exchange, dried materials are obtained, and second-time drying treatment is achieved. The brown coal drying method and device have the beneficial effects that the power plant waste heat serves as a heat source for brown coal drying, the running economical efficiency of a power plant generator set is improved, a system for drying the brown coal and a brown coal power generation system are integrated, efficient utilization of power plant energy and optimization of a technology system are achieved, and the brown coal drying method and device belong to the poly-generation technology of the power plant.

Description

technical field [0001] The invention relates to the technical field of lignite drying for clean coal power generation, in particular to a lignite drying method and drying equipment utilizing power plant flue gas and steam waste heat. Background technique [0002] Lignite is rich in reserves and low in price, and has been valued by more and more coal-fired power stations in the face of increasingly prominent energy issues. However, lignite contains 20-50% moisture, and high-moisture lignite directly participates in combustion, resulting in serious heat loss from combustion exhaust, low efficiency of generating units, poor operating economy, and high construction costs. The flue gas and steam generated during lignite combustion for power generation are often discharged as low-quality heat sources, resulting in energy waste. There are many drying techniques for lignite, which can be divided into direct heating drying and indirect heating drying according to the way in which th...

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Problems solved by technology

The above-mentioned drying methods or equipment have different problems in practical applications, such as local retention areas of materials to varying degrees. For flammable and explosive materials such as lignite and oil shale, if the local residence time in the drying equipment is too long, there will be combustion. Safety hazards such as explosion and explosion, and lead to uneven drying and poor quality of materials

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