Low energy consumption non-phase change second drying of waste straw and other biomass
Aiming at the problem of high energy consumption in traditional biomass drying,a low energy consumption non-phase transition second drying method was proposed to overcome the latent heat of phase transition.The 2 kg/h pilot test and 84 kg/h pilot test equipment of biomass non-phase change drying were independently developed,designed and built.The experimental results show that the drying conditions of straw with particle size 1-5 mm are 80℃,gas-solid ratio 9.75,gas velocity 18 m/s,residence time 10-30 s,water content can be reduced from 68％to the lowest about 15％,and the dehydration efficiency can reach more than 70％.The scaled up experiment was verified on the pilot plant.The effects of tangential,radial and axial velocities on solid-liquid separation in swirl field are revealed.In addition,64.81％of the water removed in the drying process was removed in the form of non-phase change droplets,indicating that non-phase change plays a dominant role in the drying process.The changes of particle surface morphology before and after straw drying and the further mechanism study showed that water could be separated from the pore,which may be due to the microinterface oscillation induced by the self-rotating coupling of biomass particles in the swirl field,and the pore was created on the surface of the biomass particles to enhance the centrifugal force effect to remove water in the form of microdroplets.In addition,experiments on biomass such as corn germ,distilling grains and wood chips were carried out.Under the conditions of 100℃,atmospheric pressure and residence time of 30 s,the dehydration efficiency of nearly 70％was achieved,which proved the universality of the technology for biomass types.
biomassdryingcyclone separatorcomputational fluid dynamicslow energy consumption
万方数据
维普
