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Chemical Reaction Engineering Chapter 4, Part 3: Pressure Drop in a Packed Bed Reactor
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Algorithm for Isothermal Reactor Design 1.Mole Balance and Design Equation 2.Rate Law 3.Stoichiometry 4.Combine 5.Evaluate
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Algorithm Analyze the following second order gas phase reaction that occurs isothermally in a PBR:
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Algorithm Analyze the following second order gas phase reaction that occurs isothermally in a PBR: Mole Balance: Must use the differential form of the mole balance to separate variables:
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Algorithm Analyze the following second order gas phase reaction that occurs isothermally in a PBR: Mole Balance: Must use the differential form of the mole balance to separate variables: Rate Law: Second order in A and irreversible:
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Algorithm Analyze the following second order gas phase reaction that occurs isothermally in a PBR: Mole Balance: Must use the differential form of the mole balance to separate variables: Rate Law: Second order in A and irreversible: Stoichiometry: with T=T 0
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Algorithm Analyze the following second order gas phase reaction that occurs isothermally in a PBR: Mole Balance: Must use the differential form of the mole balance to separate variables: Rate Law: Second order in A and irreversible: Stoichiometry: with T=T 0 Combine: Need to find (P/P 0 ) as a function of W (or V if you have a PFR).
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Pressure Drop in Packed Bed Reactors
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Ergun Equation:
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Pressure Drop in Packed Bed Reactors Ergun Equation:
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Pressure Drop in Packed Bed Reactors Ergun Equation:
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Pressure Drop in Packed Bed Reactors Ergun Equation: Let
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Pressure Drop in Packed Bed Reactors Ergun Equation: Let Catalyst Weight: Let and
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Multiple Reactions and Pressure Drop
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In terms of conversion:
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Multiple Reactions and Pressure Drop In terms of conversion:
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Multiple Reactions and Pressure Drop In terms of conversion:
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Analytical Solution
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Separate Integrate
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Analytical Solution For gas phase reactions, as the pressure drop increases, the concentation decreases, resulting in a decreased rate of reaction, hence a lower conversion when compared to a reactor without a pressure drop. Separate Integrate
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What if… D p and A c change? } } Laminar Turbulent
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What if… D p and A c change? } } Laminar Turbulent
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What if… D p and A c change? } } Laminar Turbulent
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What if… D p and A c change? } } Laminar Turbulent
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Polymath Solution
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