Optimization Of Compact Ozone Contact Reactor

Ozone oxidation technology has been widely used in the field of industrial wastewater treatment because of its strong oxidizing ability,fast reaction rate and less secondary pollution.However,the traditional bubble column reactor still can not effectively improve the further development of this technology,due to low ozone mass transfer efficiency,high ineffective consumption,and expensive initial cost limitations.In view of these problems,the study developed an efficient and applicable ozone contactor with campact structure based on the optimization of the reactor structure and operating parameters of bubble column and stirred reactor.And its degradation efficiency of Rhodamine B wastewater by ozone was also investigated,thus providing a technical approach and theoretical basis for strengthening the ozone gas-liquid mass transfer and reducing the ozone technology’s investment and operational costs.For the bubble column reactor,the structure is optimized by adding horizontal inner members or vertical inner members.When adding horizontal internal components,the distance between the baffles is 400 mm,the length of the baffle is 100 mm,the angle between the baffle,the horizontal is 45°,the diameter of the aeration disk is 10 μm and the aeration flow rate is greater than 10 L/min,the baffle can promote the ascending airflow to the swirl,increase the gas-liquid disturbance,strengthen the mixing,and increase the total mass transfer coefficient and oxygen transfer efficiency of the oxygen by more than 30%.When adding vertical internal members,the height of the guide tube is 780 mm,the distance between the bottom of the draft tube and the aeration plate is 100 mm,the diameter of the aeration disk is 0.2 μm,and the aeration flow rate is 0.5 L/min,the internal component can form a sufficient circulation of gas and liquid phase,prolong the gas residence time,and is beneficial to gas-liquid mass transfer,and the total oxygen mass transfer coefficient and oxygen transfer efficiency can be increased by more than 50%.For the stirred reactor,when the number of stages of the stirring paddle is three,the bottom paddle is a six-blade turbine agitating paddle,the middle and upper paddles are three-blade depressing paddles,the paddle diameter is 80 mm,the aeration disk has a hole diameter of 0.2 μm,the pitch of the blades is 140 mm,the stirring speed is 380 r/min,and the aeration flow rate is greater than 1 L/min,the agitation can enhance the gas-liquid mixing and disturbance,prolong the gas residence time,and the total mass transfer of oxygen compared to the empty tower.Both the coefficient and the oxygen transfer efficiency can be increased by more than 120%.After evaluation by the reactor,it was found that the stirred reactor had the best ozone mass transfer effect.Ozone oxidation treatment of Rhodamine B was carried out using a stirred reactor.The results showed that the stirred reactor has promotive effect of both on the treatment of different initial concentrations of rhodamine B under different ozone dosages,and the ozone utilization rate of the stirred reactor with a height of 0.75 m can reach 65.6%,which is 57.3% higher than that of the traditional bubble column.Based on the Rhodamine B continuous dynamic processing test,cost accounting is performed,which can significantly reduce operating costs compared to conventional bubble columns.