Structure Optimization Of Coal Mixing Tank Based On Numerical Simulation

In order to increase the energy utilization ratio of coal and solve the problem of environment pollution, our country attaches much importance to coal direct liquefaction technology. As the key equipment of coal slurry preparation unit coal slurry mixing tank plays a significant role in coal direct liquefaction. However, few researches focused on horizontal mixing tank both domestically and abroad at present. Our research team had researched horizontal mixing tank, but only several groups of parameters in a structure were concerned due to the limitation of time and conditions.Optimization of three coal slurry mixing tanks using computational fluid dynamics (CFD) method and physical experiment was studied in this paper, some conclusions were obtained.The further researches were initially done in turbine coal mixing tank with various model parameters to find more suitable structures for engineering application. It was found that the best mixing result was achieved using 60°inclination straight turbine oar with 188mm disc diameter and 2mm interval between baffle and tank body, while other parameters were constant.Spiral coal slurry mixing tank was also evaluated. In this tank oars were sloping arranged forming spiral trend, which not only has the traditional agitating and mixing function, but also leads the material flow along spiral orbit. At the same time, back-mixing enhanced the mixing more plenitude. Numerical simulation results showed that this equipment basically meets design demands.Based on preceding structures, colter coal slurry mixing tank was finally raised, instead of using turbine oar. This tank used colter oar to achieve higher shearing force. Especially, agitating effect was obviously improved after setting a baffle before mixture outlet. The physical experiment was carried out and validated the numerical simulation results.