Chemical Engineering & Kinetics
Academic Boot Camp
Curtis P. Martin
July 27, 2016
Reading
Silberberg: §16.1-16.3.
What is Chemical Engineering?
“Application of chemistry, mathematics, physics, biology, and economics to produce, transform, and transport chemicals, material, and energy”
Traditionally: Chemical production Oil, commodity chemicals, etc.
Currently: Synthetic biology Nanotechnology Protein engineering Medicine design Renewable energy Polymer engineering
Traditional Chemical Engineering
Main purpose: reaction scale-up
Lab scale production scale
Example:
Refining crude oil in lab per day: 1 L
Crude oil produced in US per day: ~1.5 billion L
Traditional Chemical Engineering
Getting chemical from point A to point B
Minimizing energy input (and thus, expenditures)
Heating or cooling chemical to improve physical properties Minimizing energy input (and thus, expenditures)
Managing chemical reactions
Maximizing product yield
Minimizing byproducts
Minimizing environmental impact
Traditional Chemical Engineering
Getting chemical from point A to point B
Minimizing energy input (and thus, expenditures)
Heating or cooling chemical to improve physical properties Minimizing energy input (and thus, expenditures)
Managing chemical reactions
Maximizing product yield
Minimizing byproducts
Minimizing environmental impact
Transport phenomena
Thermodynamics
Reaction engineering
Unit operations
Unit Operations
Raw materials
Product!
Unit Operations
Raw materials
Other materials
Energy
Lots of energy!
Byproducts?
Other materials Energy
Purity?
Packaging?
Phase?
Economics?
Energy Energy
Energy
Energy
Energy
Energy
Energy
Product!
Unit Operations
Raw materials
Byproducts?
Product!
𝑉 =𝐹𝐴0𝑥𝐴−𝑟𝐴
𝑑𝐸
𝑑𝑡= 𝐸𝑖𝑛 − 𝐸𝑜𝑢𝑡
+𝐸𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛
+𝐸𝑡𝑟𝑎𝑛𝑠𝑓𝑒𝑟
Transport Phenomena
Fluid mechanics, heat transfer, mass transfer
Study of how fluids flow, or react, to external forces
Conservation of momentum
Transport Phenomena
Fluid mechanics, heat transfer, mass transfer
Study of how fluids flow, or react, to external forces
Conservation of momentum
Basis of fluid mechanics
𝜕(𝜌𝒖)
𝜕𝑡+ 𝛻 ⋅ 𝜌𝒖𝒖 = 𝜌𝒈 + 𝛻 ⋅ 𝑻
fluid density
gravitational force
stress tensor
fluid velocity
Transport Phenomena
Navier-Stokes equation Combined with “continuity equation,” aka conservation of mass
Combined with constitutive equations
𝜕(𝜌𝒖)
𝜕𝑡+ 𝛻 ⋅ 𝜌𝒖𝒖 = 𝜌𝒈 + 𝛻 ⋅ 𝑻
Navier-Stokes (in x coordinate): 𝜌𝜕𝑢𝑥
𝜕𝑡+ 𝜌𝑢𝑥
𝜕𝑢𝑥
𝜕𝑥+
𝜕𝑢𝑥
𝜕𝑦+
𝜕𝑢𝑥
𝜕𝑧= −
𝜕𝑃
𝜕𝑥+ 𝜇
𝜕2𝑢𝑥
𝜕𝑥2+
𝜕2𝑢𝑥
𝜕𝑦2+
𝜕2𝑢𝑥
𝜕𝑧2
Navier-Stokes (in y coordinate): 𝜌𝜕𝑢𝑦
𝜕𝑡+ 𝜌𝑢𝑦
𝜕𝑢𝑦
𝜕𝑥+
𝜕𝑢𝑦
𝜕𝑦+
𝜕𝑢𝑦
𝜕𝑧= −
𝜕𝑃
𝜕𝑦+ 𝜇
𝜕2𝑢𝑦
𝜕𝑥2+
𝜕2𝑢𝑦
𝜕𝑦2+
𝜕2𝑢𝑦
𝜕𝑧2
Navier-Stokes (in z coordinate): 𝜌𝜕𝑢𝑧
𝜕𝑡+ 𝜌𝑢𝑧
𝜕𝑢𝑧
𝜕𝑥+
𝜕𝑢𝑧
𝜕𝑦+
𝜕𝑢𝑧
𝜕𝑧= −
𝜕𝑃
𝜕𝑧+ 𝜇
𝜕2𝑢𝑧
𝜕𝑥2+
𝜕2𝑢𝑧
𝜕𝑦2+
𝜕2𝑢𝑧
𝜕𝑧2
Transport Phenomena
Fluid mechanics is common among engineering disciplines
Thermodynamics
Governs how energy transforms within a system
Work: transfer of energy used to displace a body of mass
Heat: flow of energy by means other than work
Internal: energy associated with random motion of molecules within system
Entropy: confusing property which: Measures the number of ways a thermodynamic state may be
arranged
Determines the direction in which a system may proceed
vs
Reaction Engineering
Study of reactions and everything that comes with them
Yield How much product does a reaction make?
Specificity
Which reaction is dominant when multiple are present?
Catalysis Introduction of inert compounds which lower activation energy of the reaction
Thermodynamics How much heat (or work) does the reaction take (or produce)?
Kinetics How fast does a reaction occur?
Reaction Engineering: Kinetics
Every reaction occurs with a certain rate
Reaction rate: Actual rate at which reaction occurs
Typically denoted rx
Rate constant:
Proportionality constant
Typically denoted kx
Ba(NO3)2(aq) +Na2SO4(aq)՜kfBaSO4(s) + 2NaNO3(aq)
x labels the direction of reaction or the reaction it is describing
Reaction Engineering: Kinetics
Given the reaction:
Where lower case letters are stoichiometric coefficients and upper case letters are compounds
If the reaction is elementary, it may be written as:
Where [X] is the concentration of X and rA is the reaction rate for A
In this course, all reactions will be treated as if they were elementary
aA+bB ՜kfcC + dD
rA = kf[A]a[B]b
Kinetics: Example
Given:
What is the rate of consumption of BaNO3?
Ba(NO3)2(aq) +Na2SO4(aq)՜kfBaSO4(s) + 2NaNO3(aq)
Kinetics: Example
Given:
What is the rate of consumption of BaNO3?
Ba(NO3)2(aq) +Na2SO4(aq)՜kfBaSO4(s) + 2NaNO3(aq)
−rBaNO3= kf[Ba(NO3)2][Na2SO4]
Kinetics: Example
Given:
What is the rate of consumption of BaNO3?
What is the rate of production of BaSO4?
Ba(NO3)2(aq) +Na2SO4(aq)՜kfBaSO4(s) + 2NaNO3(aq)
−rBaNO3= kf[Ba(NO3)2][Na2SO4]
Kinetics: Example
Given:
What is the rate of consumption of BaNO3?
What is the rate of production of BaSO4?
Ba(NO3)2(aq) +Na2SO4(aq)՜kfBaSO4(s) + 2NaNO3(aq)
+rBaSO4= kf[Ba(NO3)2][Na2SO4]
−rBaNO3= kf[Ba(NO3)2][Na2SO4]
Chemical Engineering: The New Stuff
Synthetic biology
Nanotechnology
Protein engineering
Medicine design
Renewable energy
Polymer engineering
Nanotechnology
Utilizing nanoscale properties to engineer new things
Catalysis
Altering the kinetics of a reaction by changing its mechanism
Nanoparticles
Gold nanoparticles as tumor detection method
Nanowires for electrical conduction nanochips
Carbon nanotubes for material strength betterment
Renewable Energy
Chemical properties and reactions for energy production
Solar cells
Classical hard materials (Si, CdTe)
Using polymers… flexible, simple manufacturing, cheap
Batteries
Chemistry used to produce electricity
Fuel cells
Synthetic Biology
Utilizing the organized chaos of nature
Logic gates
Biochemicals (de)activate metabolic pathways which direct chemical production
Protein synthesis
Introduction of “plasmids” into bacterial cell to produce biomolecules
Biosensors Detect small biomolecules via expression of proteins
Questions?
Next time:
Chemical equilibrium
Homework #3:
Due Tuesday, July 28