Cold Model Experimental Research On Hydrogenation Slurry-bed Reactor In Hydrogen Peroxide Production

Hydrogen peroxide,as oxidant,bleaching agent,disinfectants,polymer initiator and crosslinking agent,is widely used in papermaking,textile,chemical synthesis,medicine,food processing,cosmetics,military industry,environmental protection,m etallurgy and other industries.At present,the production capacity of hydrogen pero xide in China was more than 10 million tons annually,accounting for 1/3 of the g lobal total.With the increase of domestic demand,the production of hydrogen pero xide will greatly increase in China.Hydrogenation reactor is one of the key equip ments in hydrogen peroxide production,and slurry bed hydrogenation reactor with anthraquinone method is the advanced technique.However,the research on the reac tor is still not enough,especially it is still not clear on the hydromechanics in the reactor,which restricts its domestic manufacturing and equipment large-scaling.So,cold model experiments were done on hydrogenation slurry-bed reactor with anthr aquinone method,and the changes of bubble size,gas holdup and liquid velocity in the reactor were investigated.1)A cold model pilot experimental setup was established.Three trioctyl phosphate was selected as the liquid phase,which is the solvent in the hydrogation process in H2O2 production with anthraquinone method.Alumina powders were selected as solid phase.New reactor-internals and cold model pilot experimental slurry-bed reactor were designed.2)The changes of bubble size along the axial position were detected.Bubble size increases with the increase of axial height in the slurry bed,and bubble size decreases with the increase of radial distance.With the increase of superficial gas velocity,bubble size decreases.Under the condition that the solid ratio is less than or equal to 2%,the addition of fine particles did not affect the size of the bubble.The internals can promote the radial diffusion of the bubble.The break of bubble mainly happened in the center of the reactor,and there is less effect on the bubbles break in the area near wall.3)The holdup of gas in the reactor along the axial position were detected.The local gas holdup increases with the increase of axial height,and decreases with the increase of r/R in the radial position.The gas holdup in the central region is large,and it is small in the area near wall,and the overall trend is parabolic.The gas holdup increases with superficial gas velocity,especially in the central region.The addition of internals makes the distribution of local gas content more uniform in the radial position,and the overall average gas holdup is increased.4)The changes of liquid velocity in the reactor were also determinated.In the slurry bed reactor,there are two regions where liquid flowed upward or flowed downward.The turning point of the liquid movement is between r/R =0.6~0.8,and the axial liquid velocity is the smallest near the wall,which is close to 0.Axial liquid velocity increased with the increase of superficial gas velocity.With the increase of r/R in the radial position,the effect of the superficial gas velocity on the axial liquid velocity decreased.With the addition of internals,the axial liquid velocity was reduced,and the moving direction of the liquid was shifted to the side wall of the reaction,and the circulation scale of the liquid phase became smaller and the degree of liquid remixing decreased.