Mixing Patterns in a Novel Riser Simulator

Pekediz, A.; Kraemer, Dan; Chabot, J.; Lasa, Hugo I. de

doi:10.1007/978-94-011-2747-9_6

Cited by 17 publications

(22 citation statements)

References 8 publications

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“…The experiments seem to support that the formation of styrene monomer can easily proceed via thermal cracking; this would be an important first step for the subsequent catalytic molecular reordering according to the properties of the catalysts. Styrene dimers or trimers were not observed in any of the runs, either thermal or catalytic, a fact that can be assigned to the high temperature used and the very efficient contact between reactants and catalyst particles that can be achieved in the reactor employed (Pekediz et al, 1992).…”

Section: Resultsmentioning

confidence: 91%

Recycled Plastics in FCC Feedstocks: Specific Contributions

Puente

Arandes

Sedrán

1997

Ind. Eng. Chem. Res.

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Following a tertiary recycling option for plastics focused on the FCC process, styrene-based polymers were dissolved in benzene and injected over fresh and equilibrium samples of a commercial FCC catalyst. Reaction times were up to 12 s in a discontinuous fluidized bed reactor at 550 °C. The major reaction products were ethylbenzene, benzene, toluene, and styrene, and the production of coke was very significant. A reaction mechanism which includes polymer thermal cracking, surface oligomerization of styrene molecules, and further cracking, in parallel to hydrogen-transfer reactions, was delineated based on the comparison of the catalytic behaviors of the different samples. Increases in the yields of ethylbenzene, styrene, and coke are predictable for the industrial conditions.

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Section: Resultsmentioning

confidence: 91%

Recycled Plastics in FCC Feedstocks: Specific Contributions

Puente

Arandes

Sedrán

1997

Ind. Eng. Chem. Res.

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“…All of the experiments were performed in a batch, fluidized-bed, stirred tank reactor, the Riser Simulator 16 that has been described thoroughly elsewhere. ,, It is to be mentioned that, because of very intense mixing in the unit, external (fluid-phase) temperature and concentration gradients are excluded . The experimental conditions were the following: temperatures of catalyst E, 475, 500, and 550 °C; temperatures of catalyst O, 440, 500, and 550 °C; mass catalyst-to-reactant ratio, 5.15; mass of catalyst, 0.8 g; reaction times, from 0.5 to 10 s. After reaching the target experimental conditions, the following steps were performed: injection of the reactant with instantaneous vaporization, previous filling of the reactor with inert nitrogen at atmospheric pressure, reaction during a given contact time, evacuation of the reactor's gas phase, which is essentially instantaneous, and analysis by on-line capillary gas chromatography.…”

Section: Methodsmentioning

confidence: 99%

Simultaneous Diffusion, Adsorption, and Reaction in Fluid Catalytic Cracking Catalysts

Bidabehere

Sedrán

2000

Ind. Eng. Chem. Res.

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Simultaneous diffusion, adsorption, and reaction that take place inside the zeolitic component of equilibrium commercial fluid catalytic cracking (FCC) catalysts were described by means of heterogeneous models. n-Hexadecane was used as a test reactant at high temperatures (440−550 °C) over two different equilibrium catalysts under very short contact times up to 10 s in a Riser Simulator reactor. The system's parameters were obtained by fitting the model to the reactant's gas-phase concentration versus reaction time data. When zeolite intracrystalline diffusion was first assumed as the controlling mechanism for mass transfer, its energy of activation resulted close to the heat of adsorption, suggesting that diffusion in the zeolite micropores could be indeed controlling. The solution under this new approach led to the obtention of parameters that were consistent with the existence of strong diffusion limitations for the reaction and with lower activity in the low unit cell size catalyst. Diffusion, which would be a nonactivated process, had coefficients that were essentially the same in both catalysts, while the energies of activation of the reaction were different and reflected the higher relative importance of the mechanism of monomolecular cracking in the more dealuminated catalyst. The need for a careful assessment of adsorption parameters in FCC catalysts was confirmed by the fact that their magnitudes change significantly as a function of temperature, with adsorption being somewhat stronger on the higher unit cell size catalyst in the temperature range of interest for FCC. The method employed proved to be adequate and sensitive for the quantification of these issues, which are important in reactor design and simulation and catalyst evaluation procedures.

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“…The CREC riser simulator is a well‐mixed batch reactor which operates under isothermal conditions 10, 20. Reaction rates for each component i can be expressed as follows where V is the volume of the reactor in cm 3 , W is the weight of the catalyst in grams, p i is the partial pressure of specie i , R is the gas constant in cm 3 atm K −1 mol −1 , T is the reactor temperature in ° K , and t is the time in seconds.…”

Section: Overall Kinetic Modelmentioning

confidence: 99%

Unsymmetrically Substituted 9,10‐Dihydro‐9,10‐diboraanthracenes as Versatile Building Blocks for Boron‐Doped π‐Conjugated Systems

Januszewski

Lorbach

Grewal

et al. 2011

Chemistry A European J

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The targeted hydrolysis of the 9,10-dihydro-9,10-diboraanthracene adduct (Me(2)S)HB(C(6)H(4))(2)BH(SMe(2)) (1) with 0.5 equiv of H(2)O leads to formation of the borinic acid anhydride [(Me(2)S)HB(C(6)H(4))(2)B](2)O (2) and thereby provides access to the field of unsymmetrically substituted 9,10-dihydro-9,10-diboraanthracenes. Compound 2 reacts with tBuC≡CH to give the corresponding vinyl derivative in an essentially quantitative conversion. Subsequent cleavage of the B-O-B bridge by LiAlH(4) with formation of hydridoborate functionalities is possible but is accompanied by partial B-C(vinyl) bond degradation. This situation changes when the related mesityl derivative [MesB(C(6)H(4))(2)B](2)O (7) is employed, which can be synthesized from BrB(C(6)H(4))(2)BBr (6) by treatment with 1 equiv of MesMgBr and subsequent hydrolysis. The reaction of 7 with LiAlH(4) in tetrahydrofuran (THF) furnishes Li[MesB(C(6)H(4))(2)BH(2)] (8); hydride elimination with Me(3)SiCl leads to formation of the THF adduct MesB(C(6)H(4))(2)BH(THF) (9·THF). Alternatively, 7 can be transformed into the bromoborane MesB(C(6)H(4))(2)BBr (10) by treatment with BBr(3). A Br/H-exchange reaction between 10 and Et(3)SiH yields the donor-free borane MesB(C(6)H(4))(2)BH (9), which forms B-H-B bridged dimers (9)(2) in the solid state. The vinyl borane MesB(C(6)H(4))(2)BC(H)=C(H)Mes (14) is accessible from MesC≡CH and either 9·THF or 9. Compared with the related compound Mes(2)BC(H)=C(H)Mes, the electronic absorption and emission spectra of 14 reveal bathochromic shifts of Δλ(abs)=17 nm and Δλ(em)=74 nm, which can be attributed to the rigid, fully delocalized π framework of the [MesB(C(6)H(4))(2)B] chromophore.

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Mixing Patterns in a Novel Riser Simulator

Cited by 17 publications

References 8 publications

Recycled Plastics in FCC Feedstocks: Specific Contributions

Recycled Plastics in FCC Feedstocks: Specific Contributions

Simultaneous Diffusion, Adsorption, and Reaction in Fluid Catalytic Cracking Catalysts

Unsymmetrically Substituted 9,10‐Dihydro‐9,10‐diboraanthracenes as Versatile Building Blocks for Boron‐Doped π‐Conjugated Systems

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