Research And Development Of New High-efficiency Mixing Equipment System With Air Lifting Rotary Circulation

A high efficiency and energy-saving air lift rotary circulation mixing device is developed in this paper.The rotating nozzle is installed at the inlet of the mixer or the outlet of the forced liquid material circulation of the pump.The rotating and injection of the rotating nozzle can strengthen the mixing of the radial material and drive the material in the jet area for weekly movement.The liquid flow can well disperse and push out the reaction or heating or circulating gas from the external conduit of the liquid pipeline from the connecting nozzle to form a central gas-liquid dispersed swirl region.The lift force produced by the gas and liquid gravity difference promotes the upward movement of the material to the upper axis,and the material with high central gas content flows upward and the material with low external gas content flows downward,eventually forming an overall fast circulation.The ingenious design of the direct jet to form a swirling flow and circulation can maximize the friction mixing and axial motion of the material,and can maximize to avoid the circumferential motion with the whole rotation of the animal material,and this circumferential movement energy is large and the circumferential movement contributes little to the mixture.The new mixing device mainly consists of a container and a rotating nozzle(invented by our research group,consisting of fixed and nozzle rotating parts),liquid and gas transport or circulation system.Research results show that:The rotational speed and jet radius of the rotary nozzle can be adjusted by liquid or gas flow or pressure.The diameter of gas distribution area can be determined by liquid flow rate and pressure,gas flow rate and nozzle type.In an experimental device with a diameter of 1.2 meters,a volume of 1.5 cubic meters and a liquid height of 1.3 meters,an axial uniform bubbling mixture can be formed when the gas flow is less than 3(m3/h),an axial circulation mixing can be formed when the gas flow rate is greater than 3(m3/h).The main factor affecting the gas holdup is the gas flow,increasing the flow rate of the nozzle and liquid can also increase the gas holdup,and the gas holdup and gas flow show a linear relationship.The range of the gas holdup is 0%-0.35%.The rate of circulating liquid is mainly determined by the flow rate of gas,and the rate of circulating liquid increases with the increase of gas flow.Liquid flow and fan nozzle also have a certain effect on the rate of circulating liquid.The increase of the rate of circulating liquid will be smaller when the liquid flow increases,and the number of the fan nozzle can also increase the speed of the circulating liquid.Increasing the liquid flow can shorten the mixing time.When the gas flow rate is increased,the mixing time decreases first and then increases.The best mixing conditions were:liquid flow rate 5(m3/h),gas flow rate 7(m3/h),two wide angle nozzle and two fan nozzle.Further studies show that the time of saturation of dissolved oxygen decreases with the increase of gas,and the effect of liquid flow and nozzle combination is small.When the liquid flow rate is 6.6(m3/h)and the gas flow rate is 10(m3/h),the actual power of the new mixing equipment is 4(kW/h).