Lecture 8 Flashcards
What is the definition of reaction rate?
the change in concentration of a species per unit time
Why is the definition of reaction rate inadequate for flow reactors at steady state?
Because moles change with position in the reactor, not time
In a generic reactor system, what does F_jo stand for?
molar flow of species j into the reactor
In a generic reactor system, what does F_j stand for?
molar flow of species j out of the reactor
In a generic reactor system, what does G_j stand for?
generation of species j inside the reactor
What is the general mole balance of a system?
In - Out + Generation = Accumulation
F_jo - F_j + G_j = dNj/dt
What does N_j represent in the general mole balance of a system?
The number of moles of species j in the system at a time (t)
If all the system variables are spatially uniform throughout the system volume, the rate of generation of species j, Gj is represented by what equation?
G_j= r_j * V
Briefly Describe a Batch Reactor.
perfect mixing, no concentration or temperature gradients withing the vessel. Uniform composition and Temperature at any given time
Briefly Describe a CSTR.
Same as a batch reactor except that it is a flow reactor at steady state
Briefly Describe a PFR?
A tubular reactor with no axial mixing and no radial composition or temperature gradients
Briefly Describe a PBR.
Like a PFR only it is packed with a catalyst
What are the assumptions of a batch reactor?
uniform composition and temperature at any point in time. Composition and temperature change with time
What are the steps to run a batch reactor?
-Charge all reactants in at the beginning
-close the reactor and bring to temperature and allow the reaction to run
-when finished drain the products from the reactor
-clean and begin again
What phase is mostly used in CSTR?
liquid phase reactions
