A high-efficiency dust removal and anti-condensation steam rotary drying process and lignite drying method

Abstract

The invention relates to an efficient dedusting anti-condensation steam rotary drying process and a lignite drying method. The efficient dedusting anti-condensation steam rotary drying process comprises a dried material flow process, a drying steam flow process, a cloth bag dedusting anti-condensation flow process, a moisture carrying gas flow process and a heat tracing flow process, a cloth bag dust remover is used as an efficient dust removal device, superheated steam is used as cycled moisture carrying gas in the drying process, moisture removed by the dried materials is taken out of the steam rotary drying machine to form moisture carrying tail gas, and the moisture carrying tail gas is subjected to the efficient dust removal of the cloth bag dust remover and the saturated steam heat exchange temperature rise and returns to the steam rotary drying machine to form a closed cycle. The process and the method have the advantages that the consumption quantity of nitrogen gas in the drying moisture carrying process is effectively reduced, the system safety is improved, the goals of efficient dust removal, energy saving, environmental protection and water saving are realized, in addition, a mode of heating the clean superheated steam through heat exchange of a heat exchanger is adopted, the energy consumption is low, the safety is good, the energy is saved, the environment is protected, the economic cost is low, and the regulation performance is good.

Description

technical field [0001] The invention relates to a steam rotary drying process, in particular to a high-efficiency dust removal and anti-condensation steam rotary drying process, and also relates to a method for drying lignite by using the process. Background technique [0002] For some high-moisture mineral materials, such as lignite, in order to apply them on a large scale, methods such as drying and upgrading must be used to increase their use value. Represented by lignite, it often shows the characteristics of flammability and pulverization during the drying process, which puts forward higher requirements for the design of the drying process in terms of safety and environmental protection. In terms of process safety, the drying method of direct contact between hot flue gas and lignite is difficult to maintain below 5% in a long-term and stable manner due to the oxygen content in hot flue gas, and the system has a large safety hazard. Therefore, the existing lignite dryin...

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Problems solved by technology

[0003] Currently disclosed steam indirect heat exchange and rotary processes mostly use nitrogen or a combination of nitrogen and hot air to carry moisture. The outstanding disadvantages are: 1. The consumption of nitrogen is large, and the operating cost of the system is relatively high; 2. Non-condensing in the tail gas High gas content is not conducive to water recovery; 3. In terms of environmental protection of the process, due to the high moisture content in lignite and the high partial pressure of water vapor in the humidity-carrying gas, dew condensation is prone to occur in the follow-up dust removal equipment. To a large extent, the use of high-efficiency dust removal equipment such as bag filter is limited; 4. The current indirect steam heat exchange and rotation process mostly uses cyclone dust collector. Due to the low efficiency of ordinary dust removal equipment such as cyclone dust collector, the system The dust concentration in the exhaust gas is high, which brings great difficulties to the subsequent waste heat recovery and water recovery process for the exhaust gas

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