Development of a downer reactor for fluid catalytic cracking

Talman, J.A.; Geier, Reiner; Reh, Lothar

doi:10.1016/s0009-2509(98)00378-9

Cited by 35 publications

(12 citation statements)

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“…Similarly, low activation energy has been encountered in the simulation of cumene cracking in a Downer reactor [36], and for n-hexadecane cracking [2], which may represent accurately the behaviour of the virgin gasoil feed. On the other hand, the cracking activation energy is higher for strippable coke (175 kJ/mol), and this can explain the apparent difference between the gasoil cracking activation energy found from the two models.…”

Section: Resultsmentioning

confidence: 99%

“…Soft coke is totally removed by an adequate stripping in most lab units, but may not be fully removed in the FCC www.elsevier.com/locate/apcata Applied Catalysis A: General 287 (2005) [34][35][36][37][38][39][40][41][42][43][44][45][46] stripper due to a limited efficiency derived from stripper geometry and vapour flow rate. The ratio of soft to hard coke obtained at the exit of the riser reactor depends on catalyst properties, especially vapour aging [20].…”

Section: Introductionmentioning

confidence: 99%

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Kinetic and decay cracking model for a MicroDowner unit

Corma

Melo

Sauvanaud

2005

Applied Catalysis A: General

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Kinetic and decay cracking model for a MicroDowner unit

Corma

Melo

Sauvanaud

2005

Applied Catalysis A: General

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“…Most works reported in the literature on downer hydrodynamics relate to fluid catalytic cracking application 38,39 ; the present contribution is arguably one of the first considerations of a synthesis reaction for making a chemical intermediate in a downer. The comparison of downer and riser as a potential contactor for partial oxidation is based on the two criteria:…”

Section: 34mentioning

confidence: 95%

Modeling of partial oxidation in gas–solids downer reactors

2009

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Selective partial oxidations represent an important class of reactions in the process industry. Of particular interest is the partial oxidation of n-butane to maleic anhydride (MAN), which is arguably the largest commercialized alkane partial oxidation process. Partial oxidation of n-butane, which uses vanadium phosphorous oxide (VPO) as a heterogeneous catalyst, is believed to operate through a unique mechanism in which lattice oxygen oxidizes n-butane selectively to MAN. Past work has shown that performing partial oxidation reactions in gas-solids riser configuration is realizable and commercially viable, which has lead to commercialization of this technology in the last decade. Though the riser configuration allows optimal and independent control of the oxidation and reduction steps, the riser unit suffers from solid backmixing at walls, which in turn result into lower conversion, nonoptimal selectivity and diminished overall yield of desired product. In recent years, there has been growing interest in downers involving cocurrent downflow of both solids and gas phases, hence offering relatively uniform flow characteristics. In this contribution, we explore through modeling the implications of effecting partial oxidation reactions in a downer (gas-solids cocurrent downflow) compared to that in a conventional riser reactor (gas-solids cocurrent up flow) operated under equivalent operating conditions. Further, we explore the operational space of downers for these reactions, suggesting ways for improving the productivity of downer for partial oxidation applications. V

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“…5,6 Additionally, downer reactors offer the advantage of fast reaction time with an intermediate as the desired product, for example, a uid catalytic cracking reaction. [7][8][9][10][11] The plug ow approach of this reactor improves the selectivity for the desired product. Thus, several researchers attempted to explore the detailed hydrodynamics and mass and heat transfer along with the chemical reactions of this reactor type.…”

Section: Introductionmentioning

confidence: 99%