文档介绍：CHEMICAL REACTOR
CHARATERIZATION
GOALS:
u Outline basic concepts
u Review reaction chemistry
u Develop basic definitions of performance
u Identify important reactor variables
u Review reaction thermodynamics
9/20/99 Chemical Reactor Characterization 1
PURPOSE OF A CHEMICAL REACTOR
The purpose of a chemical reactor is to convert
less desirable ponents
into
more desirable ponents.
uConvert a cheap raw material into a more valuable
products, ., natural gas into ammonia, ethylene into
polyethylene, etc.
uConvert pounds into ones that are
environmentally benign, ., hydrogen sulfide into sulfur,
carbon monoxide into carbon dioxide, PCB’s into CO2,
H2O, and HCl.
9/20/99 Chemical Reactor Characterization 2
CHEMICAL REACTIONS
u A chemical reaction is an exact recipe for converting
raw materials into products or byproducts
u The key concept is that of the stoichiometric coefficient
u The stoichiometric coefficient aij specifies the mols of
the ponent produced per mol of the jth reaction.
u Reactions take place in mols, not mass!!
9/20/99 Chemical Reactor Characterization 3
EXAMPLE #1
1) CH4 + 2 O2 --> CO2 + 2 H2O
2) CH4 + 1 1/2 O2 --> CO + 2 H2O
ponent ai1 ai2
1 CH4 -1 -1
2 O2 -2 -
3 CO2 1 0
4 CO 0 1
5 H2O 2 2
9/20/99 Chemical Reactor Characterization 4
CONVERSION AND SELECTIVITY
u Conversion is that fraction ponent entering a
reactor that is converted to products and byproducts
u Conversion is generally based on one or more
independent ponents of primary interest in the
reaction system
u The selectivity of a ponent with respect to a
specified product is the fraction of ponent
converted to the specified product divided by the total
conversion of the ponent.
9/20/99 Chemical Reactor Characterization 5
EXAMPLE #2
Reactor Material Balance:
Mols/hr in
Component Feed Effluent Delta
CH4 100 20 -80
O2 200 50 -150
N2 400 400 0
CO2 0 60 60
CO 10 30 20
H2O 0 160 160
9/20/99