Rate laws, CSTR and PFR design, conversion, catalysis, PID control, process safety and engineering economics.
40 cards · basic cards · AI-written, checked twice. Edit anything.
- What is reaction rate?
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The speed at which reactants are consumed or products are formed, measured as concentration change per time.- What is the general form of a reaction rate law?
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rate = k[A]^m[B]^n, where k is rate constant and m,n are reaction orders.- What does overall reaction order mean?
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The sum of all exponents (m+n) in the rate law; determines how rate depends on concentration.- What is the Arrhenius equation?
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k = A*e^(-Ea/RT), where A is frequency factor, Ea is activation energy, R is gas constant, T is absolute temperature.- How does temperature affect reaction rate constant?
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Rate constant increases exponentially with temperature, roughly doubling for every 10 C rise (rule of thumb).- What is a CSTR?
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Continuous Stirred Tank Reactor where reactants enter and exit continuously with perfect mixing throughout.- What is the mole balance equation for a CSTR at steady state?
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F_A0 - F_A - V*r_A = 0, or equivalently V*r_A = F_A0*(1-X).- What is space time?
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Space time (tau) = V/F_0, the reactor volume divided by volumetric feed rate, in units of time.- For a first-order CSTR, what is the relationship between conversion and space time?
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X = k*tau/(1+k*tau), where k is rate constant; conversion increases but approaches asymptotic limit.- Why is CSTR preferred for highly exothermic reactions?
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Good temperature uniformity due to mixing; heat generation is distributed throughout reactor volume.- What is a major disadvantage of CSTR compared to PFR?
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Larger reactor volume needed for same conversion because entire reactor contents are at exit concentration.- What is the mean residence time in a CSTR?
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Equal to space time (tau), the average time a fluid element spends in the reactor.- What happens when CSTR reactors are arranged in series?
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Each reactor operates at its exit composition as inlet; overall conversion increases compared to single CSTR.- What is a PFR?
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Plug Flow Reactor where fluid moves as a plug with no mixing in the axial direction.- What is the design equation for a PFR?
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V = integral from 0 to X of [F_A0/(-r_A)] dX, relating volume to conversion and reaction rate.
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