Theoretical Analysis And Experimental Study On Process Characteristics In Spin Flash Dryer

Spin Flash Dryer(SFD) belongs to the category of pneumatic drying equipment, which combines crushing, drying, separation and collection processes all together. Energy consumption of drying equipment is still a serious question. So the study on SFD flow field and material drying characteristics based on numerical simulation and drying experiment, has a certain guiding significance to process optimization, energy conservation and equipment improvements.The SFD is designed by the author in dependent. On the one hand, with the aid of Fluent(numerical simulation software), the gas-solid flow numerical simulation of the SFD model is completed. On the other hand, this paper discusses the distribution laws of hot wind temperature, material humidity and etc. in different conditions of inlet velocity, hot wind temperature and blade rotation speed, and explore the heat and mass transfer mechanisms in drying area using SFD experiment platform. Based on the above research method, the research results and conclusions are acquired as follows:(1)In the aspect of numerical simulation, the continuous phase pressure drop is mainly distributed in the spin outside-tube section, annular gap section and the main drying area. The pressure drop per unit length in annular gap section is the largest, which reaches 3.61Pa/mm. Through analysis of particle phase in the steady state distribution, get the estimate value of residence time of = 0.29 s. Through the DPM transient simulation of the discrete phase with Multicomponent method, material drying characteristics curves are obtained and analyze the drying process in deep.(2)In the aspect of experiment study, the causes of differences between experimental data and simulation data are analyzed, and find that heat losses, a mixture of material composition and separation device are the main reasons. The results and deviations are got as follows: 1)In the curve of hot air temperature change with cylinder height, there are some differences between the simulation values and experiment values. In the condition of T=400K, the biggest difference is 11.3K at h=440mm of the cylinder. 2)The material humidity decreases rapidly with the increase of hot wind temperature. The simulation value is 8.3% while the experiment value is 5.4% in the condition of T=340K. 3)There exists a turning point in the curve of material humidity and(v=22m/s,X=2.88%)is the experimental turning point. 4)Blade speed has a smaller impact on the material humidity compared with other factors.(3)The simulation values and experiment values are in the same good trend, although there still exists some deviations. As a result, the theoretical model of this paper can be used as a kind of auxiliary means of studying the characteristics of flash drying process.