Tubular reactor dynamic analysis

This example models the dynamic behaviour of an non-ideal isothermal tubular reactor in order to predict the variation of concentration, with respect to both axial distance along the reactor and flow time. Non-ideal flow in the reactor is represented by the axial dispersion flow model. The analysis is based on a simple, isothermal first-order reaction. 

In Damkohler s analysis, which applied to a continuous chemical reaction process in a tubular reactor, he solved these dilemmas by completely abandoning geometric similarity and fluid dynamic similarity. In other words, L/D idem and assuming that the Reynolds number is irrelevant in the scaling. Hence, his scale-up depends exclusively on thermal and reaction similarity. In our case it is even easier to see that the Reynolds number is very small and does not play a role in the process. By allowing to adjust L/D accordingly, there is more flexibility in the scaling problem. 

Computational fluid dynamics (CFD) approaches are emerging as alternative detailed tools for examining polymerization systems with complex mixing and reactor components. Recent examples on LDPE cases include Kolhapure and Fox [118], micromixing effects in tubular reactors Zhou etal. [119], tubular (and autoclave) reactors Wells and Ray [120], analysis of imperfect mixing effects applicable to many reactive flow systems, including LDPE autoclaves and Buchelli etal. [121], fouling effects. 

Dynamic analysis of tubular reactors(both packed or empty) has the following main characteristics ... 

In this work, thermal cracking reactors of ethylene plants are investigated dynamically. The main attention is given to the cracking coil. The modelling of the furnace itself is not considered.The tubular reactor is modelled by assuming the external wall temperature profile or heat flux profile of the coil. There is no report on dynamic analysis of this type of reactor in the literature except Jackman and Arises work (12). The literature is mainly interested in the steady state modelling of these reactors and control. 

Bonvin,D., R.G.Rinker and D.A.Mellichamp. "Dynamic Analysis and Control of a Tubular Reactor at an Unstable State". Chem.Eng. Sci. v35 (1980) 603-612. 

Kirkbir,F. "Dynamic Analysis of a Tubular Reactor". M.Sc.Thesis Middle East Technical University, Turkey. (1984). 

Kinetic analysis of main reactor in dependence on used catalytic system showed (see 5.2) that under oligomerization of piperylene initiated by AICl3-0(C6H5)2 it is advisable to use tubular turbulent apparatus. Not high values of dynamic viscosity of liquid oligo-piperylene rubber at output of reactor (at 283 K, i = 1 mPa Sec) allows also perfecting of stage of catalyst deactivation by propylene oxide or water (Fig. 6.8b). 

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