Dynamic effects of vaporization with exothermic reaction in a porous catalytic pellet

Watson, Paul C.; Harold, Michael P.

doi:10.1002/aic.690390609

Cited by 41 publications

(44 citation statements)

References 38 publications

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“…28 At the reaction conditions, the vapor pressures of AMS, cumene, and hexane are well below 30 kPa. 29 Therefore, there is little expectation of liquid vaporization.…”

Section: Methodsmentioning

confidence: 99%

Effect of hydrodynamic multiplicity on trickle bed reactor performance

Merwe

Nicol

Al‐Dahhan³

2007

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com).Multiple hydrodynamic states in trickle bed reactors have been the subject of numerous hydrodynamic investigations. The extent of variation in the hydrodynamic parameters (like holdup and pressure drop) is large and this variation can be expected to have a significant impact on the conversion in a reaction system. This study presents reaction data for a-methyl styrene hydrogenation in a trickle bed reactor over a range of conditions that include gas and liquid limitations. It is seen that liquid flow rate variation induced hysteresis has a large impact on the conversion. For gas-limited reactions, the upper branch of the pressure drop hysteresis loop has a higher conversion than the lower branch at the same linear fluid velocities and catalyst weight, while for liquid-limited reactions the lower branch has a higher conversion than the upper branch (the difference in productivity being up to 20%). These trends cannot be explained by differences in wetting efficiency. Instead, it is proposed that for this system the gas-liquid mass transfer rate is the limiting step in gas-limited reactions, while the liquid-solid mass transfer rate is the limiting step in liquid-limited reactions.

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“…28 At the reaction conditions, the vapor pressures of AMS, cumene, and hexane are well below 30 kPa. 29 Therefore, there is little expectation of liquid vaporization.…”

Section: Methodsmentioning

confidence: 99%

Effect of hydrodynamic multiplicity on trickle bed reactor performance

Merwe

Nicol

Al‐Dahhan³

2007

AIChE Journal

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show abstract

“…We chose this model reaction for several reasons: (1) the exothermic character ( H = −118 kJ/mol) offers a possibility to show the advantages of microreactors in temperature control, (2) a change in the operating variables (p, T) has significant influence on the reaction rate and (3) this reaction serves as a model for many significant reaction classes in the chemical, process and petroleum industries. It is well described in the literature [20][21][22][23].…”

Section: Hydrogenations In Microreactorsmentioning

confidence: 98%

Transparent silicon/glass microreactor for high-pressure and high-temperature reactions

Trachsel

Hutter

Rohr

2008

Chemical Engineering Journal

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“…When the liquid flow is cut off, the reaction takes place between the liquid holdup and the flowing hydrogen (zone B). Hydrogenation reactions are characterized by a relatively large heat of reaction, and interruption of the liquid flow reduces heat removal from the reactor and elevates bed temperatures (Watson and Harold, 1993) (zone Bl). Under these conditions evaporation of the liquid phase followed by gas phase reaction may occur.…”

Section: Cycling Experimentsmentioning

confidence: 99%

“…The experiments were carried out in order to achieve all three possible steady states in the reaction system: a gaseous-phase-reaction regime with externally fully dry catalyst pellets, a liquid-phase-reaction regime with a catalyst external surface totally covered with liquid-reaction mixture, and, eventually, a mixed-phase-reaction regime where part of the string was externally, completely wetted by the liquidreaction mixture and the other part was externally, completely dry. Watson and Harold (1993) used a single-pellet catalytic reactor to study dynamic effects of vaporization with exothermic reaction in a porous catalytic pellet. The experiments allowed the simultaneous measurement of pellet weight (liquid holdup) and center temperature under conditions that mimic the unsteady local events within a fixed-bed multiphase reactor.…”

Section: Introductionmentioning

confidence: 99%