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