Photolysis of Hydrocarbons
Group 13: Josh Mardis, John Lubatti, Greg Smith, Travis Watson
Sponsor: Ken Edwards of Eglin Air Force Base
FAMU-FSU College of Engineering
Background
The United States produces approximately 6 billion metric tons of CO2 emissions a year.
Fig. 1: From Dr. Krothapalli’s Lecture 4 Slides for EML4450
Background
Carbon dioxide absorbs the long wave radiation that is emitted by the earth’s surface and reemits radiation back to the surface.
An overabundance of greenhouse gases in the atmosphere can cause an increase in Earth’s natural average temperature.
Project Scope
Design a device to dissociate jet fuel into carbon and molecular hydrogen to provide on demand hydrogen production to power a small propulsion system (10hp). The desired process for dissociation of the fuel was photolysis, as requested by the sponsor.
The design should separate and collect the particulate so it can be recovered and sold.
Project Scope
Photodissociation of JP-8Result:
Carbon Particulate and Molecular Hydrogen
Separator
Hydrogen to 10HP Propulsion SystemCarbon Particulate to Collector
for Recovery
Photolysis
Photolysis (also known as photodissociation) is a method of separating a molecule into smaller parts using light.
Photolysis of Hydrocarbons
Photolysis of hydrocarbons can render varying products depending on the conditions of the environment and other reactants involved.Other hydrocarbonsPolymers
Photolysis of Hydrocarbons
Once a molecule has been excited by a photon, it can either emit of photon, dissociate, or lead to other chemical processes.
Complexities
If the subject can be dissociated, the products in the mixture can react with each other, creating unwanted byproducts.Environment must be suitable that
encourages molecular hydrogen production. Energy needed to dissociate the subject. High temperatures
Other Methods of Hydrocarbon Dissociation Steam Reformation
A large amount of hydrogen production comes from steam reformation of methane. Process produces CO2.
Thermal DecompositionRequires a lot of energy.
Specifics of Dissociation
C-H bond has energy of approximately 413 kJ/mol
Our objective is to break and separate The idea is to use a polymer that is
accepting of the by-products leaving only molecular hydrogen
Calculations
413kJ/mol divided by Avogadro’s number gives 6.858E-22 kJ per molecular bond
Convert to wavelengthλ = hc/E = 290 nm
Intensity (photons/time) Lux (intensity/area)
What intensity and lux do we need?
Logistics
LasersFrequencies neededPurchasing and costBeam sizeMultiple angles
Questions
Would multiple beams at different angles be necessary?
η = Po/Pi. Is this method efficient? What size of incident laser area is
necessary? Could we keep the dissociated molecules
separate?
Chemical Composition of JP-8 Isooctane ------------------------------------------3.66% Methylcyclohexane ------------------------------3.51% M – Xylene ---------------------------------------3.95% Cyclooctane ------------------------------------- 4.54% Decane ------------------------------------------ 16.08% Butylbenzene -------------------------------------4.72% 1,2,4,5 – Tetramethylbenzene ----------------- 4.28% Tetralin ------------------------------------------- 4.14% Dodecane --------------------------------------- 22.54% 1 – Methylnaphthalene ------------------------- 3.49% Tetradecane ------------------------------------ 16.87% Hexadecane ------------------------------------ 12.22%
Other Addictives in JP-8
Stabilizers Corrosion
Ice inhibitors Anti – static
Biocides Gum cleaner
Varnish cleaner
New Project Focus
Using Hydrogen gas in an Remote Piloted Aircraft Engine
Looking at other Alternative fuels for use in I.C.E.’s
Feasibility of converting a traditional R.P.A. Engine for Hydrogen use.
Determine the Processes involved in the Conversion LA Series OS RC Aircraft Engine
Things To Focus On
Look at similar processes for use with other alternative fuels, such as Natural Gas, Propane, Biodiesel, etc.
Flammability Ranges For Different Fuels
Look at the safety issues involved with using these fuels in an I.C.E.
Do a Benefits analysis for these fuels vs. Gasoline
Emphasis On Safety!!
Design Goal for Next Semester: Convert a small R.P.V. (remotely piloted
vehicle) engine for use with one of the studied fuels.
Evaluate it’s efficiency vs. gasoline Determine it’s cost effectiveness Determine if the emissions are cleaner vs.
gasoline