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CHE 354
Chemical Reactor Design
Friday, January 11, 2007
Chapter 1
Rate Laws
How do we identify a
chemical species?

Kind

Number CH3CH3 +H2  2 CH4

Configuration
The coenzyme folic acid (left) and the
anti-cancer drug methotrexate (right)
are very similar in structure. As a result,
methotrexate is a competitive inhibitor
of many enzymes that use folates.
Production
of Aniline
Unipol Low Density Polyethylene
Note: One of the H will
be replaced by R for a
co-monomer.
Ribbon diagram of the enzyme TIM, surrounded
by the space-filling model of the protein. TIM is
an extremely efficient enzyme involved in the
process that converts sugars to energy in the
body.
How do reactions take place?

Decomposition

Combination

Isomerization
Catalytic Cracking
Fischer Tropsch Synthesis
CH4 + O2 + H2O → H2 + CO
(not balanced)
(2n+1)H2 + nCO → CnH(2n+2) + nH2O
Butane Isomerization
Rate of Reaction
rate = amount/(time x “volume”)
amount [=] mol, g
time [=] s, min, h
“volume” [=] L (dm3), kg cat, m2 cat
rA = mol/s/L
rA’ = mol/s/g
rA” = mol/s/m2
Rate of Reaction (cont)
CH3OH + H2O  CO2 + 3 H2
A + B  C + 3D
rA = -k CA (assume elementary)
= rB = -rC = -rD/3
Reaction Order
1st Order -rA = k CA
2nd Order -rA = k CA2
?? Order -rA = k1 CA/(1+k2 CA)
What do these functions look like?
Batch Reactor Design Equation
dC A
 k1C A
 rA 
dt
1 k 2C A
Just a material balance!
Let’s check this out with Polymath!