Chenlong Duan
China University of Mining and Technology, China
Title: Dry and separation of fine lignite in pulsed fluidized bed system
Biography
Biography: Chenlong Duan
Abstract
Lignite is an abundant raw coal resource, which is increasingly implemented as a primary energy supply worldwide. However,due to the characteristics of high moisture content, high ash content, high volatile content and low calorific value etc., the direct combustion of lignite resuts in low combustion efficiency, high transportation cost. In order to implement lignite as energy source and increase the utilization efficiency, the upgrading of lignite by discarding and removing moisture prior to direct use is necessary. Coal separation and simultaneously drying technologies have the superiorities of avoiding lignite slimming in separation process and attenuating the adverse effect of liquid bridge between lignite particles on particle diffusion and stratification in the separation process. The pulsed fluidized bed is typical coal separation and drying system, which implements pulsating air flow to promote the diffusion and stratification of particles and improve the dying performance and separation efficiency. In the proposed work, a novel autogenous medium pulsed fluidized bed system was established targeting at separating and simultaneously drying the fine lignite. The core of the system involves: gas heater, pulsating system and fluidized bed with thermocouple measuring equipment. The electrical heater consists of electrical heating tubes. Controller is responsible for setting the range of heating temperature in order to satisfy experimental requirements. In the experiment, the drying process and separation process were conducted simultaneously under different superficial velocities. After each separation, the products were sampled and analyzed in terms of ash content and moisture content. Results show that the calorific capacity have been increased significantly and the moisture content of lignite has been decreased.