Water-recyclable superheat steam drying lignite system and process method thereof

Abstract

The invention discloses a water-recyclable superheat steam drying lignite system and a process method thereof. The water-recyclable superheat steam drying lignite system comprises a dryer which is respectively connected with a moisture-carrying gas cycle unit, a water recycling unit and a condensate water flash unit; the moisture-carrying gas cycle unit comprises an electric heater, the input end of the electric heater is connected with a bag-type dust collector which is connected with a cyclone storage device, a cyclone dust collector is connected with the output end of the dryer, and the output end of the electric heater is connected with the input end of the dryer; the water recycling unit comprises the cyclone dust collector, the bag-type dust collector, a wet-type electrostatic precipitator, an air cooling device, a water cooling device and a water treatment unit, and the cyclone dust collector, the bag-type dust collector, the wet-type electrostatic precipitator, the air cooling device, the water cooling device and the water treatment unit are connected in sequence; the saturated condensate water flash unit comprises a flash tank, a cooling device and a boiler, and the flash tank, the cooling device and the boiler are sequentially connected. The wet-type electric precipitation technology is adopted for the water recycling unit, and the goals of lignite heat value increase, a high water recycling rate, multistage heat utilization and the like are achieved.

Description

technical field [0001] The invention relates to a water recoverable superheated steam drying lignite system and a process method thereof, belonging to the technical field of energy saving and environmental protection. Background technique [0002] With the introduction of various national encouragement and support policies during the "Twelfth Five-Year Plan" period, the lignite comprehensive clean utilization industry has ushered in a stage of rapid development. As we all know, lignite is one of the important fossil energy sources. Its resources are as high as 319.438 billion tons, accounting for about 13% of the country's proven resources. However, lignite has "three highs and two lows" (high moisture\volatile\ash and low calorific value \Ash melting point), easy weathering and spontaneous combustion, especially its moisture content is as high as 30% to 50%. If it is used for direct combustion, not only the overall thermal efficiency is low, but also the content of water v...

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Problems solved by technology

[0005] The present invention aims at the problems of high wet tail gas pulverized coal content in the steam drying lignite water recovery process and complicated system purification process, and provides a superheated steam drying lignite system capable of water recovery and its process method. The process adopts a specific tail gas purification method, The key parameters for the operation of the dust removal system are proposed for the wet tail gas, so that the pulverized coal content of the wet tail gas can reach the "near zero" standard, and the goal of efficient water recovery in the steam drying lignite system can be achieved

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