Lignite drying technology of high temperature downstream to promote the use of resource-rich lignite reserves, but the low grade or three high and two low water (usually around 30% -60%), ash, volatile water, lighted, heat the value of low grade fuel, such a high water has seriously hampered the development and utilization of lignite. Especially in high moisture, reduce the heat, desiccation can not only enhance the heat, as well as conducive to the storage, loading, transport, Dong Ding dry according to the physical and chemical characteristics of the lignite has mastered and controlled lignite drying temperature, pressure, wind speed and other related parameters, the development of lignite drying device settings. The system by thermal drying of coal products, deep dehydration process, effectively improve the heat index and Chu shipment performance, so that the indicators meet the requirements of commodities steam coal, with significant economic, environmental and social benefits. The system configuration sealed explosion-proof devices to eliminate the security risks of the lignite drying process, the technology in a leading position in the industry have a significant role in promoting the development of the lignite energy use. 
 Breakthrough and promote the use of lignite drying technology of high temperature downstream the dry Dongding an important innovation: the low-temperature flue gas countercurrent drying, flue gas flow and coal flow to the contrary, lead to the whereabouts of the process of coal fine particles upward airflow Trust live, over the problem of dryness, the potential for spontaneous combustion or explosion; coal leaving the dryer before and temperature flue gas exposure, resulting in the export of coal high temperature, further cooling of the export of dry coal to produce great pressure brought about the consequences liable to spontaneous combustion; low-temperature flue gas, dry the antipyretic media is a low-temperature flue gas, the less heat into the unit mass of gas imports in the dryer outlet temperature by the dew point temperature limitations should not be too therefore requires a large amount of traffic, the use of direct combustion flue gas, you need a fairly large excess air ratio, flue gas oxygen content is high, the hidden danger of spontaneous combustion explosion, even with the flue gas recirculation, recycling excessive power consumption is too high, the economy severely affected. In addition, the low-temperature flue gas drying dehydration is generally unsatisfactory. 
 Borrowed from the low-temperature flue gas counter-current drying technology, dry flue gas can use high-temperature flue gas, flue gas flow can be used and coal together into the same direction of flow downstream, resulting in a high-temperature flue gas downstream of lignite drying technique [12]. 
 High temperature flue gas of lignite drying technology compared with other brown coal drying technology has several advantages: 
 (1) to avoid part of the pulverized coal particle retention and its too dry; 
 (2) the outlet temperature of the dry product coal is low, to facilitate further cooling to prevent spontaneous combustion; 
 (3) flue gas recirculation amount is small, easy to control the oxygen content in flue gas; 
 (4) dry flue gas temperatures are high, the reasonable control of temperature, improve moisture extrusion rate, the destruction of the particle surface hydrophilic functional groups, which will help to improve the dehydration of lignite moisture relapse performance; 
 (5) In order to improve the dehydration rate conditions; 
 (6) is conducive to large-scale system is simple, flexible operation.