I need some reference to understand the basic criteria to choose certain DT/dp value
Dear;
hope that you are well.
Fischer- tropsch reactors may be fixed, fluidized bed reactors or they may be slurry reactors. This reaction is exothermic and care must be given to the limitations of mass and heat transfer to avoid hot spots within the catalyst particles, affecting seriously the catalyst effectiveness and selectivity , activity and life due to sintering phenomena accompanying these limitations
in fixed bed reactors particle sizes must be selected in conjunction with reaction kinetics (operating conditions) so that a high effectiveness factor value is achieved and no channeling phenomena in the tubes are observed, the trend is towards very small catalyst particle size . on the other side ,small particle can push towards a high pressure drop and particles erosion phenomena and low bed voidage.
Me i do recommend a tube length /diameter ratio in the range 250- 500
and tube diameter to catalyst particle ranging from 24 to 130. for sure you can make a short investigation on the effect of particle size on the hydrodynamics and intrinsic kinetics of the reaction.
in slurry and fluidized beds , you must chose very small particles or ultra fine particles
Jamal Amous
Thanks for your response sir.
You recommended that tube diameter to catalyst particle can be ranged between 24 and 130. If such ratio is used, wall effects on velocity profile of gas may become negligible. But, due to the exothermicity of the process, temperature will be highest at the centre due to large tube diameter, then the rate of reaction will vary in the radial direction.
How to overcome this limitation?
Dear;
The wide range for the ratio, gives you the opportunity to overcome this dissatisfaction,
you must push towards a turbulent flow regimeso you take care of Peclt and Reynolds numbers( diffusion corfficient, tube length, reactants velocity in the reactor)
Jamal Amous
Sir,
Could you suggest any reference materials for better understanding of fixed bed reactor design