ASTM D7739-11
(Practice)Standard Practice for Thermal Oxidative Stability Measurement via Quartz Crystal Microbalance
Standard Practice for Thermal Oxidative Stability Measurement via Quartz Crystal Microbalance
SIGNIFICANCE AND USE
The tendency of a jet fuel to resist the formation of deposits at elevated temperature is indicative of its oxidative thermal stability. This practice provides a technique for the simultaneous determination of deposit formation and oxygen consumption during the thermal oxidation of jet fuels and other hydrocarbon liquids. The practice can be used to evaluate the thermal stability of fuels and to determine the efficacy of additives in inhibiting deposition or slowing oxidation, or both. A test temperature of 140°C and run length up to 16 h has been found to be effective for the relative evaluation of fuels and fuel additives. This practice has also been employed for other hydrocarbon liquids, such as gasoline and diesel fuels, but additional safety issues may need to be addressed by the user.
SCOPE
1.1 This laboratory practice covers the quantitative determination of surface deposits produced during the thermal oxidation of gas turbine fuels by monitoring the oscillation frequency of a quartz crystal during thermal exposure. In this practice, “thermal oxidative stability” refers to the tendency of a fuel to resist surface deposit formation during heating.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D7739 − 11 AnAmerican National Standard
Standard Practice for
Thermal Oxidative Stability Measurement via Quartz Crystal
Microbalance
This standard is issued under the fixed designation D7739; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Significance and Use
3.1 The tendency of a jet fuel to resist the formation of
1.1 This laboratory practice covers the quantitative determi-
deposits at elevated temperature is indicative of its oxidative
nation of surface deposits produced during the thermal oxida-
thermal stability. This practice provides a technique for the
tion of gas turbine fuels by monitoring the oscillation fre-
simultaneous determination of deposit formation and oxygen
quency of a quartz crystal during thermal exposure. In this
consumptionduringthethermaloxidationofjetfuelsandother
practice, “thermal oxidative stability” refers to the tendency of
hydrocarbon liquids. The practice can be used to evaluate the
a fuel to resist surface deposit formation during heating.
thermal stability of fuels and to determine the efficacy of
1.2 The values stated in SI units are to be regarded as the
additivesininhibitingdepositionorslowingoxidation,orboth.
standard. The values given in parentheses are for information
Atest temperature of 140°C and run length up to 16 h has been
only.
found to be effective for the relative evaluation of fuels and
fuel additives. This practice has also been employed for other
1.3 This standard does not purport to address all of the
hydrocarbon liquids, such as gasoline and diesel fuels, but
safety concerns, if any, associated with its use. It is the
additional safety issues may need to be addressed by the user.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4. Apparatus
bility of regulatory limitations prior to use.
4.1 All dimensions without tolerance limits are nominal
values.
2. Summary of Practice
4.2 Reactor—A T316, 100 mL stainless steel reactor cylin-
2.1 A quartz crystal, fitted with gold electrodes, is fully
der with an internal diameter of 5.23 cm (2.06 in.) and a depth
immersed in test fuel contained within a reactor. An oscillator
3, 4
of 4.93 cm (1.94 in.). A T316 stainless steel reactor head
circuit, connected to the crystal, supplies energy to excite the
with several openings (for example, gas inlet via dip tube, gas
quartz crystal and monitors its resonant frequency (nominally
release fitted with a dial gauge or pressure transducer,
5 MHz) over time via a computer interface. The reactor is
thermocouple, safety rupture disk, frequency signal
equipped with a magnetic stir bar, pressure gauge/transducer,
connection, sleeve for oxygen concentration probe). A 0.952
oxygen sensor (not recommended for certain test conditions,
cm (3/8 in.) hole is drilled in the center of the reactor head to
see 4.11), and thermocouple to monitor and control test
accommodate the frequency signal connectors. This hole shall
conditions. Prior to testing, the fuel is bubbled with the test gas
have a 0.952 cm (3/8 in.) clearance from any adjacent opening.
for 30 min to equilibrate.After equilibration, the reactor vessel
is isolated and raised to test temperature and pressure. As 4.3 SMACoaxial ConnectorAssembly—This assembly pro-
deposits accumulate on the crystal surface during the run, the vides the electronic connection through the reactor head to the
crystal frequency decreases. The shift in resonance frequency
quartzcrystalandconsistsofseveralkeyparts(seeFig.1).The
can be quantitatively related, in real time, to surface deposit cable from the oscillator (see 4.6) connects to a subminiature
2 4,5
accumulation via a variation of the Sauerbrey equation.
version A (SMA) adapter plug. The SMA adapter plug
The sole source of supply of the apparatus (Parr Instrument cylinder model
This practice is under the jurisdiction of ASTM Committee D02 on Petroleum #452HC8 (100 mL)) known to the committee at this time is Parr Instrument
Products and Lubricants and is the direct responsibility of Subcommittee D02.J0.03 Company, 211 Fifty-Third St., Moline, IL 61265-1770.
on Combustion and Thermal Properties. If you are aware of alternative suppliers, please provide this information to
Current edition approved June 1, 2011. Published August 2011. DOI: 10.1520/ ASTM International Headquarters. Your comments will receive careful consider-
D7739–11. ation at a meeting of the responsible technical committee, which you may attend.
2 5
Klavetter, E. A., Martin, S. J., and Wessendorf, K. O., “Monitoring Jet Fuel The sole source of supply of the apparatus (Part No. 3037M-1) known to the
Thermal Stability Using a Quartz Crystal Microbalance,” Energy & Fuels, Vol 3, committee at this time is Coaxial Components Corp., 10 Davinci Dr., Bohemia, NY
1993, pp. 582-588. 11716-2601.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7739 − 11
FIG. 1 SMA Coaxial Connector Assembly
4,6 4,10
connects to two male SMA connectors. The male SMA may be purchased commercially. The insulator between the
connectors are first welded together, and then laser welded in adapter and the coaxial conductor pin may be fashioned by
4,7 4,11
place on both sides of the reactor head. Amating set of SMA
machining or carefully fracturing ceramic tubing.
connectors (male and female) was not used since these were
4.7 Oscillator—A phase lock oscillator that measures the
not available in 0.952 cm (3/8 in.) diameter. The threaded end
frequency of the quartz crystal and provides a DC voltage
of the SMA connector on the bottom of the reactor head
signal proportional to the conductance of the crystal. Suitable
connects to the Quartz Crystal Adapter (see 4.5).
4,12
for quartz crystals with a resonance frequency of 5 MHz.
4.4 ReactorHeater—Openbottombandheaterusedtobring
4,8
4.8 FrequencyCounter—Tomeasurethefrequencyfromthe
test fuel to temperature.
4,13
oscillator. Frequency resolution shall be 60.1 Hz.
4.5 Heater Controller—Proportional-integral-derivative
(PID) controller for regulating the open bottom reactor band
4.9 Multimeter/Data Acquisition System (DAS)—Measures
4,9
heater. A second heater controller may be used as a high
the conductance voltage, pressure, temperature, and other
4,14
temperature safety cut-off should the outside skin temperature
monitored parameters and transmits data to a computer.
of the reactor exceed a preset limit.
4.10 Thermocouples—K-type used to measure test fuel
4.6 Quartz Crystal Adapter—Required to both properly
temperature and outside reactor skin temperature (if so
align the quartz crystal and suspend the quartz crystal in the
equipped).
test fuel. Proper installation of the quartz crystal in the adapter
will complete an electrical circuit in which the quartz crystal is
the frequency controlling element of the oscillator.The adapter
The sole source of supply of the apparatus (part numbers 950132, 950133,
is based on a design by the Sandia National Laboratories and
950135 through 950138) known to the committee at this time is Raytheon Ktech,
1300 Eubank Blvd. SE, Albuquerque, NM 87123.
The sole source of supply of the apparatus (Part No. R1201) known to the
The sole source of supply of the apparatus (Part No. 9251000) known to the committee at this time is Scientific Instrument Services, Inc., 1027 Old York Road.
committee at this time is Insulator Seal Inc., 6460 Parkland Dr., Sarasota, FL Ringoes, NJ 08551-1054.
34243-4036. The sole source of supply of the apparatus (Inficon PLO-10i phase lock
The sole source of supply of the apparatus (laser welding) known to the oscillator) known to the committee at this time is Inficon, Two Technology Place,
committee at this time is Precision Joining Technologies, Miamisburg, OH. East Syracuse, NY 13057.
8 13
The sole source of supply of the apparatus (Parr Instruments Model A2235 The sole source of supply of the apparatus (Agilent Models #53131A or
HC2EB, 110 VAC and A865HC11EB) known to the committee at this time is Parr 53181A) known to the committee at this time is Agilent Technologies, Inc., 5301
Instrument Company, 211 Fifty-Third St., Moline, IL 61265-1770. Stevens Creek Blvd., Santa Clara, CA 95051.
9 14
The sole source of supply of the apparatus (Eurotherm 2216E, Cal 9500P, and The sole source of supply of the apparatus (Keithley Model #2700) known to
Parr 4842 controllers) known to the committee at this time is Parr Instrument the committee at this time is Keithley Instruments, Inc., 28775 Aurora Rd.,
Company, 211 Fifty-Third St., Moline, IL 61265-1770. Cleveland, OH 44139.
D7739 − 11
4.11 MagneticStirPlateandStirBar—To maintain test fuel
temperature homogeneity. The stir bar is polytetrafluoroethyl-
ene (PTFE) coated with the following dimensions, 3 mm
4,15
diameter by 12.7 mm long.
4.12 Oxygen Concentration Sensor and Transmitter—To
monitor and record the consumption of oxygen throughout the
4,16
run. The use of an oxygen concentration sensor and
transmitter is not recommended when operating with a test gas
containing more than 25 vol% oxygen. Oxygen operation
presents the possibility of detonation and this equipment may
not withstand this sudden increase in pressure.
4.13 Pressure Transducer—A pressure transducer can be
4, 17
used in place of a dial gauge. When operating with oxygen
or a test gas containing more than 25 vol% oxygen extra
caution is needed. Oxygen operation presents the possibility of
detonation and the pressure transducer may not withstand this
sudden increase in pressure.
5. Reagents and Materials
5.1 Quartz Crystal—A 2.54 cm (1 in.) diameter, AT-cut,
4,18
polished silica wafer sandwiched between gold electrodes. FIG. 2 Quartz Crystal (Front) Showing Proper Location of Indium
Wire
Anew quartz crystal shall be used for each run. The front side
of the crystal contains the smaller of the two circular elec-
trodes. The crystal will be installed in the Quartz Crystal
combustible liquids. Appropriate shielding should be used for
Adapter (see 4.5) in a specific orientation.
any con
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.