Next Generation OBIGGS: Developments at Phyre Technologies Santosh Y. Limaye Phyre Technologies, Inc. November 2, 2005 Atlantic City, NJ Presented at International Aircraft Systems Fire Protection Working Group Meeting

The Concept Treat the ullage from the fuel tank to create inert gas Inexpensive catalytic system Avoid the use of bleed air This concept resulted from liquid fuel de-oxygenation system development

High Heat Sink Fuels: Enable Advanced Propulsion Fuel Temperature, F Fuel Temperature, C Combustor Endothermic fuels pyrolytic deposits Fuel Flow JP-8 JP-8+225 JP-900 thermal-oxidative deposits JP-8+100 600 400 200 300 500 800 1000 1100 900 700 Filamentous Condensation Amorphous 2 4 6 8 10 12 14 >1300 F Deposition is The Significant Challenge for High Heat Sink Fuels Heat sink relative to JP-8 900 F 550 F 425 F 325 F JP-8 JP-8+100 JP-8+225 JP-900 Endo JP Near term Mid - Term Higher heat sink capability of fuels will enable several critical aspects of advanced propulsion. The heat sink capabilities of fuel are limited by the temperature at which fuels form deposits. Typically, these deposits are caused by thermal oxidation of the fuels, a well known phenomenon Thus, there are several strategies that allow heating the fuels to higher temperatures. These include - - Increase Thrust-to-weight enables higher T41 Reduce take-off gross weight reduce fuel recirculation & ram air HX wt Improve SFC enables higher T3 and P3 Reduce component operating temp. higher heat sink capability High Heat Sink Fuels Benefits

Quick Review of De-Oxygenation System Fuel Gas Contactor Contaminated Fuel Inert Gas De-Oxygenated Inert Gas + O2 + Fuel Vapor Gas Treatment System Oxygen free gas For Recycling Pump Separator Removing dissolved oxygen in fuel prevents premature oxidation; a primary cause of coking. Dissolved oxygen = cholesterol

Mass Transfer Issue Mass Transfer Region O2 Concentration Gradient Kinetics of sparging processes is limited by mass transfer issues at the gas liquid interface. Kinetic of membrane based de-oxygenation is limited mass transfer rate through the membrane Diesel Droplet in N2 Gas N2 Bubble in Diesel

Does it work? - - YES! Fuel O2 = 57.9 ± 5.4 ppm 10 20 30 40 50 60 0.5 1 1.5 2 2.5 3 3.5 4 Fuel Flow (lpm) O Concentration (ppm) O2 = 5 ppm Fuel O2 = 57.9 ± 5.4 ppm N2 flow: 2.5 Liter/Min; lpm Low dissolved oxygen levels are easily obtained

Results from Testing at AFRL Run75 Run79/81 Baseline JP-8 PADS Deox JP-8 (Catalyst) Visual inspection of the servo flow divider valve spool and body shows that the deposition from deoxygenated fuel is essentially the same as for additized +100 fuel. Valve hysteresis is somewhat higher for deoxygenated fuel vs additized fuel. The shape of the hysteresis curve with the balloon at the upper right seems to indicate a worn valve. Run80 Run76 PADS Deox JP-8 (Nitrogen) JP-8+100 PADS DeOx JP-8 (LN2)

OBIGGS

OBIGGS Considerations 15 10 Hydrocarbon Vapor Volume Fraction (%) Dilution with Air Inert Air Purge 5 Flammability Region Critical Dilution with Air 5 10 15 20 Oxygen Volume Fraction (%)

Catalytic Inerting System (CIS): Next Generation OBIGGS Concept Make up air to consume hydrocarbon vapor and pressure equalization Catalytic Gas Treatment System <10% oxygen + Fuel vapor + CO2 H2O + N2 21% oxygen + Fuel vapor + N2 safety device Pump Air + Fuel Vapor Water trap Fuel PATENT PENDING

CIS System Description Low Temp. air to air Heat Exchangers Inlet Oxygen Sample Port Reverse Flow Valve Heat Exchanger & Heaters Reverse Flow Valve Blower Catalyst Bed, 5” Dia x 4.5”length Inlet Size: 12”x12”x 40” Capacity: 150 CFM # of passes to 10% O2 : 3 Outlet Control Unit Water Drain Support Systems Power Automatic Moisture Drain Valves Oxygen Sensors Optional, High Removal Rate, Vapor Fuel Control

CIS Catalytic Chemistry Vapor Pressure of Nonane (Jet Fuel) T C T K VP Pa Atmospheres -46.8 226.35 1 0.00001 -26 247.15 10 0.00010 273.15 100 0.00097 34 307.15 1,000 0.00971 80.8 353.95 10,000 0.09709 150.3 423.45 100,000 0.97087 Saturated vapor phase of fuel vapor : C9H20 (Nonane) As per DOT/FAA/AR-04/8 report (page 12), the precise composition is C9.05H18.01 Vapor pressure of Nonane is estimated to be 8000 ppmv at 70F Stoichiometric Reaction of 8000 ppmv Nonane will consume 112,000 ppmv (or 11.2%) oxygen to provide 70,000 (7%) and 40,000 (4%) ppmv of CO2 and H2O .008 @ 70F Stoichiometric Reaction C9H20 + 14O2 + 52.67 N2  9 CO2 + 10 H2O + 52.67 N2

Corrected/Uncorrected Oxygen Removal Rate Pass # O2 % Corrected O2 Ratio Corrected/Uncorrected 21.00 1 13.82 14.02 1.01 2 9.09 9.45 1.04 3 5.98 6.44 1.08 4 3.94 4.46 1.13 If H2O is removed from the product, additional fresh air is needed to compensate the gas pressure in the reactant. The corrected O2 column shows new concentration based on fresh addition of air to replace water molecules. Three passes will ensure reduction of O2 below 10%.

CSR Model: Oxygen Depletion Rate For 450 Cu. Ft. Ullage

Experimental Schematic Pump Moisture trap Catalyst Downstream Temp. CDT Post Catalyst O2 Conc. Ullage O2 Conc. Catalyst Controller for heater Oxygen Sensor* Ullage Volume VU Heater Flow Rate FR Catalyst Temp. CT Fuel Volume VF Flow Meter Pressure gage Fuel Tank Experimental limitations: Very small ullage volume Limited flow rate control Objective was proof of concept to validate theoretical calculations Limitations on catalyst volume (smallest 1.2 cc) Delayed response due to long oxygen sensor lines

Initial Results – Experiment #1

Conclusion Prototype Development Testing Phase Benefits No need for bleed air, eliminate ozone destruction device Low temperature process Only power necessary: blower operation Smaller foot-print, lighter weight, lower cost Closed loop system Ability to reduce oxygen level as well as fuel vapor level Other Concerns Addressed Use of fuel vapor phase means no sulfur contamination, no corrosion Instead of purging the fuel vapor, it is consumed in the process, hence no VOC emissions from the tank Ability to precisely control gas partial pressures Next Steps Prototype Development Testing Phase Strategic Partnership Development