Study Of Rotating Packed Bed Technology In The Preparation Of Hydrogen Peroxide Using Anthraquinone Method

Hydrogen peroxide is an important inorganic chemical product which has been widely used in decomposition,inorganic and organic synthesis,and paper bleaching,etc.World consumption of hydrogen peroxide grows dramatically in recent years.Nowadays,the anthraquinone process is the most widely used process for the production of hydrogen peroxide in industry.The reactor system can be a fixed bed,fluidized bed or slurred bed,to name a few.Fixed-bed process has been widely used in China for nearly half a century.However,the fixed bed encounters problems including overheating,poor mass transfer,unsatisfied hydrogenation selectivity,low catalysis utilization,etc.Alternative technology solution/improvement for hydrogen peroxide has become an emerging issue.Rotating packed bed technology is a new technology developed in 1990 s.With the benefits of mass and heat transfer in homogeneous and heterogeneous catalysis reactions process,it is expected to provide a new design perspective in producing hydrogen peroxide.Based on the surveys and references,the research of applying rotating packed bed in hydrogen peroxide producing has not been developed.Taking the advantages of the short materiel residence time and potential good mass and heat transfer activity in the catalysis process,the product yield and selectivity of anthraquinone hydrogenation using rotating packed bed may have a potential good performance and worth study.This study,we first researched the principles and development of fixed bed reactor and rotating packed bed in industries.Followed by the introduction of design and test of fixed bed reactor and vertical rotating packed bed reactor in anthraquinone hydrogenation reactions,the vertical rotating packed bed encountered problems including low catalyst utilization,great bed resistance.To improve the design,we built a horizontal rotating packed bed reactor for the hydrogenation reaction which has a better performance.Secondly,hydrogenation reaction in hydrogen anthraquinone rasching ring Pd/Al2O3 system was studied by using the lab-made fixed bed reactor.The results showed that hydrogenation efficiency of anthraquinone increased first,then reached a peak and decreased with increasing reaction temperature.And the hydrogenation efficiency of anthraquinone increased with increasing the hydrogen pressure,the hydrogen gas space velocities,and low fluid flow.Besides,increasing the loading capacity of the catalyst and reducing catalyst size was beneficial to improve hydrogenation efficiency of anthraquinone.Anthraquinone hydrogenation performance was investigated under different rotational speed,temperatures,pressures in horizontal rotating packed bed reactor.The results showed that hydrogenation efficiency of anthraquinone increased first and then decreased with increasing rotational speed.In addition,the changes of anthraquinone hydrogenation efficiency of rotating packed bed reactor with respect to the tempeture and pressure were quite similar to that of fixed bed reactor.The optimum operation condition is as follows,rotational speed keep at 195 r/min,temperature at 60 ?,and pressure at 0.2 MPa.Under this condition,reaction was carried out by cycling 1.5 L anthraquinone working solution.The results showed that with the increase of cycle time,the hydrogen efficiency increased.After 20 min,however,degradation of product increased.Finally,we compared the results of three types of reactors: fixed bed,rotating packed bed and rotating packed bed under circulation.It is found that the hydrogenation efficiency of rotating packed bed(3.1 g/L)was lower than that of rotating packed bed under circulation,but the space-time yield of H2O2 was much higher.Thus,rotating packed bed was more economical to be operated in the high speed environment.Moreover,the rotation packed bed reactor had a better performance than fixed bed.In conclusion,we summarized the results and gave suggestions for future study directions.