For a tubular reactor characterized by space time ‘η’ and residence time ‘ζ’, which of the following principles applies?
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Answer: C. η = θ, for an isothermic tubular reactor in which the density of the process fluid is constant
Explanation
For an isothermal tubular reactor with constant fluid density, volumetric flow rates remain constant throughout. Space time is defined as reactor volume divided by entering volumetric flow rate for continuous flow systems. Mean residence time equals average fluid transit time, which mathematically aligns with space time under constant density. Space time represents the capacity metric used heavily in continuous flow tubular and packed bed reactor design. Residence time distribution describes the actual amount of time individual fluid elements spend inside reactors. Isothermal operation ensures no temperature-driven volumetric expansion or contraction affects the flowing fluid phase.
Option A is false because space time and residence time differ whenever fluid density changes along reactor length. Option B contradicts fluid mechanics since density changes cause volumetric flow variations altering space time definitions. Option D is incorrect because non-isothermal reactors typically experience significant temperature and density gradients.
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- Engineering
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- Chemical Engineering
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- medium
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