Status and Developments of Drying Low Rank Coal with Superheated Steam in China

Superheated steam drying (SSD) of low rank coal (LRC) is applied to improve the heating value and thermal efficiency and to reduce greenhouse gas emissions and the danger of spontaneous combustion. It is essential to understand the fundamental aspects of drying LRC with superheated steam supported by funds in China and the development of clean coal technology. It is also important to promote the level of scientific technology relevant to safe energy strategies. The background of SSD based on China's unique energy structure and coal production situation are presented in this article. A comprehensive overview on progress and mechanisms of SSD is provided, including the status of drying technology supported by funds in China, distribution of project field and important research institutions, physical and chemical structure of water in coal, heat and mass transfer processes, mathematical models, and some results for wood, food, hot gas, etc., with particular reference to SSD in drying of LRC in China. There are still many challenges in the application of SSD of LRC in very large-scale power plants, drying equipment, and control technology. Advanced SSD sponsored by the fund project in China shows important significance to energy savings and reducing greenhouse gas emissions.