关键词: 脉冲式气流干燥, 气-固两相流, 数学模拟

Abstract: Lignite drying is an important part of new retorting technique for lignite using solid heat carrier.In this paper,transfer process of lignite drying in an impulse pneumatic dryer,including momentum,heat and mass transfer,was studied based on two-fluid multiphase flow model.According to air drying technology,which was efficient and mature,a heat transfer mathematical model of particle acceleration and a momentum-heat transfer mathematical model of particle deceleration were established based on the force of particles in the airflow.A new optimization method for the height of impulse pneumatic dryer was proposed.The efficiency of the impulse pneumatic dryer was verified by comparing the data collected from the impulse pneumatic dryer and the traditional pneumatic dryer,which was equal in height with the impulse pneumatic dryer.The reasons for high efficiency of impulse pneumatic dryer were analyzed according to the distribution of the simulation parameters,like gas temperature,particle humidity and volumetric heat transfer coefficient along the height of the dryer.This study provided a data basis and theoretical reference for the design of impulse pneumatic dryers.

Key words: impulse pneumatic dryer, gas-solid flow multiphase flow, mathematical modeling