Research And Design Of Oxygen Mixer In Oxidation Process

One of the measures to prevent the explosion of flammable hydrocarbon gas and achieve intrinsic safety is optimizing and improving the oxygen mixer.In this paper,the mixing law of ring oxygen mixer is simulated by using computational fluid dynamics(CFD)technology.And the feasibility of the application of ring oxygen mixer in the unit of isobutane oxidation to tert-butanol is explored.The main contents and results are summarized as follows:Based on the industrialized data in ethylene oxide synthesis unit,the model of ring oxygen mixer used coaxial jet is built to simulate the influence of momentum ratio a and the jet velocity v2 and the mixer structure on the mixing.The annular pipe with enlarged inlet,the three-ring mixer and the impinging method are proposed,then the mixing effect is analyzed.The simulated results show that the oxygen mass distribution unevenness S decreases with the increase of a,and when α>10,S tends to be stable.If n and v2 change,there is no significant change in mixing.The smaller the ratio of total area of outlet jet orifices to cross-sectional area of annular pipe r is or using annular pipe with enlarged inlet,the smaller the standard deviation SQ of mass flow rate of outlet jet orifice is.The change of diameter D0 of annular pipe center has less influence on the SQ;When the diameter ratio of large and small annular pipes is D1/D2=3,the S of mixer is the smallest;The length of mixing is L>3.5 m,and the maximum oxygen mass fraction M of each downstream section tends to be stable;Compared with two-ring mixer,the three-ring mixer is more conducive to mixing.The mixing of the impinging jet mixer with the two-ring is better than that of the coaxial jet mixer with two-ring,which is close to the mixing of the coaxial jet mixer with three-ring;When n=40,v2<60 m/s,the impinging mixing effect is better;The use of the impinging jet mixer with three-ring is not conducive to mixing.The result of applying the ring oxygen mixer to the process of 100,000 t/y isobutane oxidation to tert-butanol show that the ring oxygen mixer can meet the safety requirements of isobutane oxidation to tert-butanol project;The mixing of the impinging jet mixer with two-ring is significantly better than that of the coaxial jet mixer.