Application Of Rotary Regenerative Catalytic Technology In Electronic Coating Exhaust Gas Treatment

Industrial VOCs（volatile organic compounds）,as precursors of ozone and PM_2.5,were key factors in the treatment of compound air pollution in China.Efficient treatment such as catalytic oxidation and thermal oxidation were the essential method to control VOCs emissions.The rotating regenerative catalytic oxidation（RRCO）was an integration of regenerative technology and catalytic oxidation,which had the advantages of lower energy consumption,stable airflow and larger space utilization.RRCO played an irreplaceable role in industrial areas where natural gas was not available.In this paper,the experimentation and the simulation were studied for the optimization of RRCO.Taking toluene,butyl acetate and n-heptane as representative pollutants in co-catalytic oxidation experiments to evaluate the Pt-Pd/γ-Al₂O₃ catalysts.The results showed that the catalytic oxidation of toluene was almost unaffected by other organics due to the low activation energy.The catalytic oxidation of butyl acetate was promoted in the toluene/butyl acetate mixture,but inhibited when the concentration of n-heptane was higher in the butyl acetate/n-heptane mixture.The catalytic oxidation of n-heptane was inhibited due to the influence of competitive adsorption.In order to achieve 97%conversion,the design catalytic temperature should not be lower than 380℃.The data fitting results showed that the MVK model was more suitable to describe the reaction behavior of VOCs over the catalyst with an oxidation-reduction reaction mechanism.Computational Fluid Dynamics（CFD）method was used to simulate the temperature field,velocity field and volatile organic compounds（VOCs）concentration field in the RRCO system.The structure of the rotary regenerative catalytic oxidation chamber only affected the flow rate inside the oxidation chamber.The temperature in catalytic zone played a dominant role in preheating;the airflow velocity had a significant impact on the conversion rate of the VOCs during operation,and both heat recovery efficiency and temperature increase with the decreasing velocity of the gas.To avoid VOCs fugacity and improve thermal stability,the purge air volume should be controlled at 10%of the total air volume,and the cycle period should be lower than 90s.With the experimention and simulation results,an electronic painting exhaust gas treatment of 100000 m³/h was designed.The exhaust gas was treated by dry bag dust removal-zeolite rotor-RRCO process.After running for three months,the catalytic conversion rate kept steady at 97%,and the system treatment rate hold firmly at 90%above.Until January 2021,the VOCs emission could met the requirement of DB33/2146–2018"the Emission standard of air pollutants for industrial surface coating".It provides technical reference for the actual engineering and painting exhaust gas treatment of RRCO.