【作者】 吴跃江；

【导师】 张金利；

【作者基本信息】 天津大学 ， 化学工程， 2006， 硕士

【摘要】 磁稳定床是一种新型的流化床,具有流化床和固定床的特点。但是它需要有合适的能在低温下具有较高活性的催化剂,并且催化剂还得具有磁性。而非晶态合金作为不饱和烃加氢催化剂的特点是低温加氢活性高、选择性好,而且SRNA-4本身具有磁性。将磁稳定床和非晶态合金结合,开发一种新型的反应器,是目前化工方面的一个反应器开发方面的一个方向,具有很重要的意义。利用正交实验法探讨SRNA-4催化剂的催化加氢性能,2-辛酮加氢过程,反应时间对试验指标的影响在α=0.25水平上显著,反应压力对实验指标的影响在α=0.01水平上显著,催化剂用量和反应温度则在α=0.25水平上仍不显著;适宜的反应条件为:反应温度为110℃,反应压力为1.5MPa,催化剂用量3g/300ml,反应时间3.5小时。环己酮加氢过程,反应压力对实验指标的影响在α=0.01水平上显著,反应时间、催化剂用量和反应温度在α=0.25水平上仍不显著;适宜的反应条件为:温度为90℃,而压力为1.5MPa,催化剂用量3g/200ml,反应时间2小时。研究了以SRNA-4催化剂为固相,空气为气相的气固磁稳定床的流体力学性能:最小流化速度、最小流化状态下的床层空隙率与磁场强度无关,其可以采用经典预测公式;磁场强度的增加抑制了颗粒的运动,使得局部固含率略微增加,增大了最小鼓泡速度;空塔气速的增加促进了气固磁稳定床的膨胀,加快了颗粒、气相在床中的运动,减小了固含率;粒径较小时,Pe随磁场强度以及气速的变化其变化不大;粒径较大情况下, Pe随气速增大而减小,随着磁场强度的增大,先增大后减小。利用传热探头测定磁稳定床内部的传热系数,结果表明:磁场强度的增加抑制了颗粒的运动,减小了气固传热系数;空塔气速的增加,加快了颗粒、气相在床中的运动,局部相速度增加,增大了气固传热系数;获得了预测气固磁稳定床中气固传热系数的关联式。更多还原

【Abstract】 Magnetically stabilized bed is a new type of fluidized bed, which has characteristic of both fluidized bed and fixed bed. However, it needs magnetic catalysts that have relatively high activity at low temperature. Amorphous alloy is a kind of hydrogenation catalyst with high activity and good selectivity at low temperature. Moreover, SRNA-4, one of the amorphous alloy catalyst, is magnetic. It is currently promising orientation in chemical engineering to develop new type of reactor combining magnetically stabilized bed with amorphous alloy catalyst.SRNA-4 catalyst performance was evaluated in the reaction of 2-octanone hydrogenation based on orthogonal experiment design methods. The influence of reaction time on examined index was remarkable at the level ofα=0.25, the influence of reaction pressure on examined index was remarkable at the level ofα=0.01, while the influences of catalyst amount and reaction temperature were unremarkable at the level ofα=0.25. The optimal reaction conditions are: reaction temperature is 110℃, reaction pressure is 1.5 MPa, the catalyst amount is 3g/300ml, reaction time is 3.5 h. Similarly, for another reaction of cyclohexanone hydrogenation, the influence of reaction pressure on examined index was remarkable at the level ofα=0.01, while the influence of reaction time, catalyst amount and reaction temperature were unremarkable at the level ofα=0.25, the optimal reaction condition are: reaction temperature is 90℃, reaction pressure is 1.5 MPa, the catalyst amount is 3g/300ml, reaction time is 2 h.Hydrodynamics property of gas-solid magnetically stabilized bed was studied using SRNA-4 as solid phase and air as gas phase. It is indicated that the minimum fluidized velocity and the related bed voidage are independent of magnetic strength, both of them can be estimated using traditional formula. Increasing magnetic strength restrains the movement of particles, which makes local voidage increased slightly and the minimum bubble velocity increased. Increasing superfacial velocity accelerates the expansion of gas-solid magnetically stabilized bed, promotes the movement of particles and gas phase in the bed, and decreases the solid holdup. In the case of small particles Pe almost has no change along with magnetic field and gas velocity; while for the larger particles, Pe decreases with increasing gas velocity. As the magnetic strength increases, Pe increases at the beginning then turns to decrease.更多还原