In order to reflect the actual drying process of lignite particles and provide reference for design parameters of fluidized bed gas drying lignite system

this study establishes an unsteady drying and temperature rising model of lignite particles under fluidization state based on the unsteady boundary conditions.Using the Runge-Kutta

the differential equations describing the drying process of lignite particle are simulated and calculated.And then the change rules of moisture content

temperature and flue gas temperature with time during the lignite drying process are obtained.The results show that when the gas initial temperature is 260

200 or 140 ℃

the drying rate is 0.076

0.068 or 0.054 kg/min

respectively.When the particle size is 1

3

5 or 7 mm

the drying rate is respectively 0.074

0.068

0.065 or 0.062 kg/min.When the gas flow rate is 2.8

2.5 or 2.0 m/s

the drying rate is respectively 0.068

0.074 or 0.076 kg/min.When the bed thickness is 120

200 or 300 mm

the drying rate is respectively 0.076

0.073 or 0.068 kg/min

and the recommended drying time is 3~4 min

4~5 min or 5~6 min

respectively.The optimal target moisture content of lignite is about 10% and the suitable drying temperature is 140~260 ℃.