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NBSIR 75-802

LIQUEFIED NATURAL GAS RESEARCH

at the

NATIONAL BUREAU OF STANDARDS

PROGRESS REPORT FOR THE PERIOD
1 JULY - 31 DECEMBER, 1974

D. B. Mann Editor

DIVISION • NBS-INSTITUTE FOR BASIC STANDARDS • BOULDER,

NBSIR 75-802

LIQUEFIED NATURAL GAS RESEARCH

NATIONAL BUREAU OF STANDARDS

D. B. Mann, Editor

Cryogenics Division
Institute for Basic Standards
National Bureau of Standards
Boulder, Colorado 80302

Progress Report for the Period
1 July - 31 December, 1974

at the

U.S. DEPARTMENT OF COMMERCE, Frederick B. Dent, Secretary

NATONAL BUREAU OF STANDARDS R chard W Roberts Director

Prepared for:

American Gas Association, Incorporated
1515 Wilson Boulevard
Arlington, Virginia 22209

LNG Density Project Steering Committee

(in cooperation with the American Gas Association)

Pipeline Research Committee
(American Gas Association)

Federal Power Commission
Bureau of Natural Gas
Washington, DC 20426

General Services Administration

Motor Equipment Research & Technology Division

Washington, DC 20406

U. S. Department of Commerce
Maritime Administration
Washington, DC 20235

U. S. Department of Commerce
National Bureau of Standards
Institute for Basic Standards
Boulder, Colorado 80302

U. S. Department of Commerce
National Bureau of Standards
Office of Standard Reference Data
Washington, DC 20234

Aerospace Safety Research and Data Institute
National Aeronautics and Space Administration
Lewis Research Center
Cleveland, Ohio 44135

ABSTRACT

Eighteen cost centers supported by seven other agency sponsors in
addition to NBS provide the basis for liquefied natural gas (LNG) research
at NBS. During this six month reporting period the level of effort was at
an 18 man-year level with funding expenditures of over $485,000. This inte-
grated progress report to be issued in January and July is designed to:

1) Provide all sponsoring agencies with a semi-annual and annual
report on the activities of their individual programs.

2) Inform all sponsoring agencies on related research being con-
ducted at the Cryogenics Division of NBS-IBS,

3) Provide a uniform reporting procedure which should maintain
and improve communication while minimizing the time, effort
and paperwork at the cost center level.

The contents of this report will augment the quarterly progress meet-
ings of some sponsors, but will not necessarily replace such meetings.
Distribution of this document is limited and intended primarily for the
supporting agencies. Data or other information must be considered pre-
liminary, subject to change and unpublished; and therefore not for citation
in the open literature .

Key words: Cryogenic; liquefied natural gas; measurement; methane;

properties; research.

iii

CONTENTS

Reference Data

a)
b)
c)
d)

i)
j)

Refractive Index - Fluid Methane
(NBS-NRC Postdoctoral Research)

Fluid Transport Properties

(NBS-Office of Standard Reference Data)

Cost Center

2750122

2750124

Page

LNG Fuels Safety 2750427
(NASA-Aerospace Safety and Data Institute)

Properties of Cryogenic Fluids:
Hypersonic Velocity and Thermal
Diffusivity (NBS)

Properties of Cryogenic Fluid Mixtures:
Equilibrium Properties Data, Compi-
lation and Evaluation, Prediction
Methods (NBS; NBS-Office of Standard
Reference Data)

Survey of Current Literature on LNG

and Methane (American Gas Association,
Inc. )

Thermophysical Properties Data for Pure
Components of LNG Mixtures (American
Gas Association, Inc.)

Densities of Liquefied Natural Gas (LNG
Density Consortium of 18 energy com-
panies - AGA)

Low Temperature Material Behavior
(Maritime Administration)

Program for Reducing the Cost of LNG
Ship Hull Construction (Maritime
Administration)

II. Measurement Science

a) Heating Value of Flowing LNG (Pipeline

Research Committee - AGA)

b) LNG Density Reference System

(American Gas Association, Inc.)

2750141

2750142

and
2750145

2750362

2750364

2751574

and
2752574

2750430

2751430

2756579

2751361

Contents (continued)

Cost Center

Page

III. Technology Transfer

a) LNG Technology Transfer 2750401 . 36

(Maritime Administration)

b) Federal Power Commission Consultation 2750404 4]^

(FPC)

c) LNG - Dual Fuel Auto 2750590 43

(NBS; General Services Administration) and 2750154

Title. Refractive Index of Fluid Methane

Principal Investigator . James D. Olson

Cost Center Number . 2750122

Sponsor Project Identification . NBS-NRC Postdoctoral Research
Associate Program.

Introduction . This experimental program will provide accurate measure-
ments of the refractive index of liquid and gaseous methane. The data
can be related to the fluid density by the Lorenz-Lorentz electro-
magnetic equation of state and, as such, offers the possibility of fluid
density gauging by optical techniques. This pure fluid data is essential
to the possible study of mixture refractive index properties.

Objectives or Goals . The refractive index of liquid and vapor methane
will be measured along the two-phase saturation boundary. In addition,
gaseous isotherms will be obtained at 220 K, 250 K, 280 K, and 300 K
at pressures to 200 atm. Low pressure isotherms will be measured below
the saturation boundary.

Background . The high precision interf erometric technique used to mea-
sure the refractive index was developed in this laboratory by D . E.
Diller (J. Chem. Phys. _49, 3096 (1968)). An improved optical data
gathering method was the principal modification of this technique.
Prior to this reporting period, a literature survey of Lorenz-Lorentz
and Clausius-Mossotti virial equation data was conducted. A cryostat
was constructed using the design of Diller. The saturation boundary
data and high-pressure isotherms were measured in the last reporting
period. (See NBSIR 74-373.)

Program and Results . The program was concluded with a series of low
density isothermal measurements between 140 K and 300 K. These data
can be used to analyze the virial equation of state PVT surface. A
final analysis of the data was completed and a manuscript describing
the work written. Some points of interest to the molecular theory
of refraction were considered.

Problem Areas . No problems were encountered.

Funding .

Labor

Other Costs
Total

.25 MY

5.0
1.5

6.5

Future Plans . This report concludes the program. A publication of the
results of this work has been submitted to the Journal of Chemical
Physics (1975 - in review) .

Title . Fluid Transport Properties
Principal Investigator. Howard J. M. Hanley

Cost Center Number. 2750124

Sponsor Project Identification. NBS -Office of Standard Reference
Data

Introduction. Studies of the transport properties of mixtures have |
not received the attention or support that have been given to equiv-
alent studies of pure fluids and, at this time, methods for predicting
the transport properties of fluid mixtures are unreliable. Yet
from the standpoint of the liquefied natural gas industry mixtures
are more important than pure fluids. Properties cannot be measured !
for all possible mixtures, thus adequate prediction methods are
needed in order to supply the necessary design data needed to increase
efficiency and reduce costs. i

Objectives or Goals. The long range or continuing goal of the pro-
gram is to perform a systematic study of the theories and experi-
mental measurements relating to transport properties, specifically
the viscosity and thermal conductivity coefficients, of simple mix-
tures over a wide range of experimental conditions. The specific
objectives of the program include: 1) the systematic correlation of m\
the transport properties of simple binary mixtures and the develop- '
ment of prediction techniques, 2) development of a mixture theory for
the dilute gas region and the dense gas and liquid regions, 3) exten-
sion of the theory and prediction techniques to multicomponent systems,
and 4) suggested guidelines for future areas of experimental work.

Background . A program was started in 1965 with the goal of pro-
ducing tables of fluid transport properties through many approaches;
e.g. , data correlation and evaluation, statistical mechanics, kinetic
theory, thermodynamics and statistics. The theoretical studies, along I
with data analysis, results in prediction techniques for the dilute f
gas region for monatomic and polyatomic fluids. These techniques
were then successfully extended to the dense gas and liquid regions.
To date tables of transport properties have been prepared for argon,
krypton, xenon"""'®, oxygen®, nitrogen^, fluorine^, hydrogen, helium^,
and methane^ . In addition an analytical representation of the anomalous
behavior of the thermal conductivity coefficient in the critical region
has been developed.

Program and Results . Recent results include tables of dense gas
and liquid transport properties of argon, krypton, xenon, oxygen
and nitrogen""" , and molecular dynamic calculations on the equilibrium
and transport properties of methane .

Problem Areas. There are no problem areas at this time.

Funding . July 1 - December 31, 1974

Allocation 57.5 K$

Labor 0.5 MY

Other Costs

OSRD

28. 0 K$
1. 8 K$
30. 7 K$
26. 8 K$

Total

Remaining

10. Future Plans . The transport properties of methane, ethane, and
propane will be correlated and tabulated. Mixture studies are in
progress but have to be coordinated with corresponding work on
the equation of state. Preliminary studies along this line have been
initiated.

Reference s

1. H.J.M. Hanley, R. D. McCarty and W.M. Haynes, J. Phy. Chem.
Ref. Data 3_» (1974).

2. H.J.M. Hanley and R. O. Watts, Physics (In press, 1975); Mol.
Physics (In press, 1975); Aust. J. Physics (In press, 1975).

3. H.J.M. Hanley, J. Phys . Chem. Ref. Data 2_, 619-42 (1973).

4. H.J.M. Hanley and R. Prydz, J. Phys. Chem. Ref. Data j^, 1101-14
(1972).

5. R.T, Jacobsen, R.B. Stewart, R.D. McCarty, and H.J.M. Hanley,
National Bureau of Standards Technical Note 648 (1973).

6. H.J.M. Hg^lley, R.D. McCarty, and J. V. Sengers, National
Aeronautics and Space Administration Contractor Report 2440 (1974).

7. R.D. McCarty, National Bureau of Standards Technical Note 631
(1972).

Title. LNG Fuels Safety

Principal Investigators. Neil A. Olien and A. F. Schmidt

■ 2. Cost Center Number. 2750427

3. Sponsor Project Identification. National Aeronautics and Space Ad-
ministration, Cleveland, Ohio, Aerospace Safety Research and Data
Institute. Order No. C-39327-C.

4. Introduction. The NASA -A erospace Safety Research and Data Insti-
tute (ASRDI) was established to provide a focal point for information
and research in aerospace safety. One of the areas of concern for
ASRDI is Cryogenic Fluid Safety. In fact, this was the first area of
effort for ASRDI. The thrust of the program is two-fold: first, to
provide an automated information bank for retrieving references,
and second, to publish series of state-of-the-art reviews. The
information system is now operational and contains over 5000 refer-
ences in cryogenic fluid safety. In addition, ASRDI has published
approximately ten reviews.

Until this time, ASRDI has focused its attention and efforts on the two
primary cryogenic propellants, hydrogen and oxygen. The oxygen
work was started at NBS-Boulder in 1970 and the hydrogen work in
1972. With the coming possibility of methane or LNG fueled aircraft
and the close affinity of LNG safety and cryogenic safety, ASRDI felt
that it was timely to begin work in that area.

5. Objectives or Goals. The following objectives are to be achieved:

a) Review and modify an existing Cryogenic Fluids Safety Grid and
thesaurus to include and adequately cover LNG safety.

b) Make a thorough search of over eleven information sources for
LNG information. This will include published and unpublished
material,

c) Catalog, index, abstract and put into machine readable form all
available documents located in b) above. The indexing will be done
by technical personnel with demonstrated competence in cryogenic
safety and related fields,

■ 6. Background . This program was started at NBS-Boulder by ASRDI

in 1970. Since then considerable skill and experience has been gained
in locating, processing and, most important, detailed subject indexing
of safety-related information. In addition, NBS-Boulder has been

providing detailed coverage of the LNG field for the American Gas
Association since early 1970, The present program, then, provides
an opportunity for industry, government and the public to capitalize
on the accumulated past efforts of two seemingly unrelated programs.

7. Program and Results . Under this and another ASRDI-funded program
we have started a major review of the indexing and retrieval term-
inology which will be used in the Cryogenic fuels safety information
system. This review will result in a thesaurus to be published by
NASA. The review is complete and we are now in the process of
editing and preparing the thesaurus in its final form. Most of the
terminology unique to LNG safety is now incorporated into this
thesaurus.

During the period September 30, 1974 through December 31, 1974 we
have indexed 78 papers, reports, etc. dealing directly with LNG
safety. Of these, 63 were sent to ASRDI in machine-readable form
on magnetic tape.

8. Problem A reas. None

9. Funding . September 30, 1974 - December 31, 1975

Allocation (9/30/74 - 10/1/75) 50 K$ NASA/ASRDI

10. Future Plans. The thesaurus mentioned above will be ready for

editorial review in January and should be available in published form
prior to July 1, 1975.

We will continue to index safety-related papers and should complete
approximately 200 of these in the next reporting period.

Labor
Other costs

0. 2 MY 10. 0 K$

1. 2 K$

Total 11. 2 K$

Remaining 38. 8 K$

Title . Properties of Cryogenic Fluids.

Principal Investigators. G. C. Straty, D. E. Diller
Cost Center Number . 2750141
Sponsor . NBS

Introduction. Accurate thermophysical properties data and predic-
tive calculation raethods for cryogenic fluids are needed to support
advanced cryogenic technology projects. For example, liquefied
natural gas is expected to supply an increasing percentage of the
United States' energy requirements through 1990. Liquefaction
plants, ships and receiving terminals are being constructed to
transport and store natural gas in the liquid state (LNG). Data for
LNG are needed to design low temperature processes and equipment.
Accurate data will benefit the energy industries and the consumer by
providing for safe and efficient operations and reduced costs.

Objectives or Goals. The objectives of this project are to provide
comprehensive accurate thermodynamic, electromagnetic and
transport properties data and calculation methods for technically
important compressed and liquefied gases (helium, hydrogen, oxygen,
nitrogen, methane, ethane, etc .) at low temperature s . Precise
compressibility, calorimetric and other physical property measure-
ments will be performed to fill gaps and reconcile inconsistencies.
Definitive interpolation functions, computer programs and tables
will be prepared for engineering calculations. The immediate goals
of this work are to obtain accurate sound velocity and thermal
diffusivity data for compressed and liquefied gases by using laser
light scattering spectroscopy technique s . Sound velocity data are
useful for testing the consistency of volumetric, calorimetric and
thermodynamic properties data, and are potentially useful for
density gauging applications. Thermal diffusivity data are required
for performing thermodynamic and heat transfer calculations.

Background . When light is incident on a perfectly homogeneous
fluid, the reradiated (scattered) light field sums to zero in all but
the exact forward direction. For a "real" fluid however, fluctuations,
arising through various mechanisms, destroy the perfect homo-
geneity and results in the scattering of light in other directions as
well. For example, thermally activated density fluctuations
(phonons), propagating with the characteristic velocity of sound,
give rise to scattered light which is doppler shifted in frequency
from the incident light frequency and whose spectrum contains

information on the sound velocity and attenuation. Local non-
propagating temperature fluctuations, which decay diffusively, give
rise to scattered light in a narrow frequency band about the incident
light frequency and whose spectrum contains information on the
lifetime of the fluctuations (thermal diffusivity) . Since the
frequency shifts are generally very small, it was not until the advent
of the lasers with their extremely well defined frequency, that
practical experiments using these phenomena were possible.

The application of laser light scattering techniques to obtaining
thermophysical properties data was initiated to complement and
check other measurement methods and to solve measurement
problems inherent in more conventional methods. For example
laser light scattering techniques permit measurements of so\ind
velocities for fluids and under conditions for which sound
absorption is too large to perform ultrasonic measurements; laser
light scattering techniques permit measurements of thermal diffu-
sivities under conditions for which convection interferes with
measurements of thermal conduction. The feasibility of light
scattering experiments to obtain data on binary diffusion coefficients
has also recently been demonstrated.

We have assembled and performance tested apparatus for laser light
scattering spectroscopy measurements on compressed and liquefied
gases (76 - 300 K, 350 bars). The apparatus consists of a copper
optical cell with fused quartz windows, cryostat for refrigeration
with liquid nitrogen, an argon ion laser, pressure scanned Fabry-
Perot interferometer, and photon counting equipment.

Program and Results . Preliminary data on the hypersound velocities
in pure methane have been obtained at low densities (< 14 mollt)
where the large sound absorption in methane prohibits ultrasonic
measurements. Data have been obtained along several isotherms
from 210 K to 300 K at densities down to 1 moll^.. Agreement with
previously measured ultrasonic velocities in the regions of over-
lapping data is good. (See the attached Figure. The Q indicate
the light scattering measurements, the O indicate the ultrasonic
measurements. See the report on Cost Center 2 750364 for further
discussion of the ultrasonic measurements. ) Agreement with values
calculated directly from PVT data is also satisfactory.

Problem Areas. Progress on the light scattering experiment has
been primarily limited by our assignment of priorities to other
LNG related efforts. Data already obtained has been sufficient
to enable completion of related work on methane. Additional
measurements of the hypersonic sound velocity are considered
desirable for the sake of completeness, and completion of this
project has been rescheduled accordingly.

oooooooooo
ooooooooo

s/ui 'All30n3A QNnOS

9 . Funding .

Man -years expended (July-Dec. 1974)
Equipment and/or Services Purchased
Total Reporting Period Cost
Balance Remaining (Dec. 31, 1974)

10. Future Plans.

year

Objectives and

Schedule: quarter

1975

1 2

Methane:

Measure hypersonic (GHz)
velocities in methane

Assemble and test apparatus
for Rayleigh line -width
(thermal diffusivity)
measurements on methane

0.25

1.8 K$
1 5 . 0 K$
20. 0 K$

Title . Properties of Cryogenic Fluid Mixtures.

Principal Investigators . M. J. Hiza, A. J, Kidnay (part time),
R. C. Miller (part time), and W. R. Parrish (part time).

Cost Center Numbers . 2750142; 2750145

Sponsors . NBS; NBS(OSRD)

Introduction . Accurate thermodynamic properties data and pre-
dictive calculation methods are needed to design and optimize low
temperature processes and equipment. This project provides new
experimental measurements on equilibrium properties and com-
pilations of evaluated equilibrium properties data which are suitable
for direct technological use or for the evaluation of predictive cal-
culation methods. This project supports the development of LNG
technology in the areas of separation, purification, liquefaction
and custody transfer by defining relationships between the composi-
tion, temperature, pressure, and equilibrium state properties for
mixtures related to LNG.

Objectives or Goals . The overall objectives of this project are to
provide critically evaluated data, original and from other sources,
on the phase equilibria and thermodynamic properties of cryogenic
fluid mixtures. The program has been divided into the following
elements:

a) Preparation of a comprehensive bibliography on experimental
measurements of equilibrium properties for mixtures of
selected molecular species of principal interest in cryogenic
technology.

b) Selection and/or development of methods for correlation, evalu-
ation and prediction of equilibrium properties data.

c) Retrieval and evaluation of experimental data for specific
mixture systems selected on the basis of theoretical and/or
technological importance.

d) Preparation of guidelines for future research based on the de-
ficiencies noted in (a), (b), and (c).

e) Performing experimental research to alleviate deficiencies and
provide a basis for improvement of prediction methods.

Background . A physical equilibria of mixtures re search project
was established in the Cryogenics Division in 1959. The initial
effort, based on a bibliographic search and other considerations,
was directed toward the acquisition of new experimental data on
the solid-vapor and liquid -vapor equilibria and physical adsorption
properties for a limited number of binary and ternary mixtures
of components with widely separated critical temperatures. Most
of the systems studied included one of the light hydrocarbon
species - -methane, ethane, or ethylene ( ethene ) - -wdth one of the
quantum ga se s - -helium, hydrogen, or neon. The data for these
systems led to significant improvements in the predictions of
physical adsorption equilibrium and a correlation for the predic-
tion of deviations from the geometric mean rule for combining
characteristic energy parameter s , In addition, significant new
information was obtained for interaction third virial coefficients
which was used in a correlation by one of our consultants, J. M.
Prausnitz. The approach taken in this work has been as funda-
mental as possible with the intention of having an impact on a
broad range of mixture problems.

Recent efforts have been directed toward problems associated with
systems containing components with overlapping liquid temperature
ranges, such as the nitrogen + methane system.

Program and Results . The recent progress of this program is sum-
marized as follows:

a) The comprehensive bibliography of fluid mixtures data, com-
pleted earlier, \vb.s accepted for publication by Plenum Press
as the first of a series of books for the Office of Standard
Reference Data. The published volume will be entitled:
EQUILIBRIUM PROPERTIES OF FLUID MIXTURES: A
BIBLIOGRAPHY OF CRYOGEXIC DATA . To assure that

the product is current and saleable. Plenum has asked that
the work be updated through 19 74, and that a camera-ready
copy be transmitted to them on April 1, 19 75 for publication
in June. The updating process will be a major part of the
effort for the next quarter.

b) Work is currently in progress on the conapilation and deriva-
tion of the excess Gibbs functions, critical loci, and Henry's
law constants for the systems argon + methane, nitrogen +
methane, methane + ethane, methane + propane, methane +
n-butane, and methane + isobutane. Currently, a numerical
method, referred to as orthogonal collocation, is being evalu-
ated which allows critical evaluation of liquid -vapor equilibria
data when one of the components is supercritical.

c) Measurements tiave been completed on the nitrogen +

methane system at temperatures between 130 and 180 K,
to complete the data set for the system from our labora-
tory at temperatures between the triple point (90.7 K)
and critical point (190.5 K) of methane.

8, Problem Areas . None.

9 . Funding .

Man-years expended (July -Dec ember 1974)
Equipment and/or Services Purchased
Total Reporting Period Cost
Balance Remaining (December 31, 1974)

10. Future Plans.

year

Objectives and Schedule: quarter

1975

Update fluid mixture bibliography

Complete the analysis of new
nitrogen + methane L-V
equilibrium composition data;
prepare paper for publication

Prepare short paper on results
of analysis of binary systems
data using orthogonal colloca-
tion.

Begin L-V equilibrium composi-
tion measurements on methane +
ethane mixtures

0. 7

5. 0 K$
43. 0 K$
52 . 0 K$

Title. Survey of Current Literature on LNG and Methane.
Principal Investigator. Neil A. Olien

Cost Center Number. 2750362

Sponsor Project Identification. American Gas Association Project
BR 50-10.

Introduction. It is important that all NBS personnel working in LNG,
as well as the AGA and others, keep up with what is going on through-
out the world in the LNG field. This project is designed to provide
the Current Awareness and other information services to allow work-
ers to keep abreast of new research and other developments.

Objectives or Goals. We will publish and distribute each April, July,
October and January a listing of all significant papers, reports and
patents relating to methane and LNG properties and technology. The
references will be listed under convenient subject headings. The
Quarterly will be distributed to all interested AGA member com.panies
and be made available to the general public on a subscription basis
In addition, LNG related information will be entered into the Cryo-
genic Data Center's Information System for quick retrieval. A con-
tinuing awareness of the current publication scene will be maintained
for any new periodicals to be reviewed cover-to-cover. Finally we
will update and make available comprehensive bibliographies on the
properties and technology of LNG. There are three bibliographies
involved: methane properties, methane mixtures properties, and
processes and equipment involving methane and LNG. These three
will be updated each October.

Background . In 1969 we made a thorough review of the world's pub-
lications to determine which periodicals and abstracting services
should be scanned cover-to-cover to adequately encompass the LNG
field. The result is that we now scan over 300 primary publications
and nearly 30 secondary publications . Of these approximately one-
third are directly related to LNG. In addition, within the past year
we have increased our coverage of the energy field to include hydro-
gen as a future fuel. Much of this information is also Dertinent to
LNG and as such is listed in our LNG -related publications. Our
Current Awareness Service has been published weekly since 1964 and
the Liquefied Natural Gas Survey has been published quarterly since
1970.

Pro gram and Results . Two issues of the LNG Quarterly were pre-
pared and distributed. There are now 118 subscriptions going to
AGA Member Companies and 191 to other subscribers.

The three comprehensive bibliographies mentioned in section 5 have
been reviewed and shorter, more selective bibliographies have
resulted. These were prepared in October 1973 and will be updated.

B- 1055 THERMOPHYSICAL PROPERTIES OF METHANE - A

SELECTED BIBLIOGRAPHY, 61 pp., indexed by property,
phase and author (Sept. 1973) $8. 00.

B-1056 PROPERTIES OF METHANE MIXTURES - A SELECTED
BIBLIOGRAPHY, 95 pp. , indexed by property, system and
author (Sept. 1973) $10. 00.

B-1075 PROCESSES AND EQUIPMENT INVOLVING LIQUEFIED

NATURAL GAS AND METHANE - A SELECTED BIBLIOGRAPH^
52 pp. , indexed by subject and author (Oct 1973) $5. 00

During the period July through December 1974 we have distributed 19
copies of these and the comprehensive bibliographies.

Problem Area s. We have no problem areas at this time.

Funding . July 1 - December 31, 1974.

Labor 9 7 K$

Other Costs 1. 8 K$

Total 1 1. 5 K$

Remaining 6. 5 K$

Future Plans. Issue 74-4 of the LNG Quarterly will be mailed to the
National Technical Information Service for printing and distribution
on January 10, 1975. Is sue 75 - 1 will be published in April The
three comprehensive bibliographies discussed in Item 7 above are
in the process of being updated and will be available for distribution
the latter part of January 1975.

Jan. Feb. Mar. Apr. May Jun

Search of Current Literature
Preparation of Issue 75-1
Preparation of Issue 75-2

)

1. Title. THERMOPHYSICAL PROPERTIES DATA FOR PURE
COMPONENTS OF LNG MIXTURES

Principal Investigators. R. D. Goodwin, G. C. Straty
Cost Center Number . 2750364

Sponsor . American Gas Association, Inc., Project BR50-10

Introduction. Accurate phase equilibrium, compressibility (PVT),
and thermodynamic properties data are needed to design and optimize
gas separation and liquefaction processes and equipment. Accurate
data for the pure components of LNG mixtures will permit developing
comprehensive accurate predictive calculation methods which take
into account the dependence of the the rmophysical properties of
mixtures on the composition.

This project will provide comprehensive accurate the rmophysical
properties data and predictive calculation methods for compressed
and liquefied hydrocarbon gases to support the development of LNG
technology at NBS and throughout the fuel gas industry.

Objectives or Goals. The objectives of our work are the determina-
tion of comprehensive accurate the rmophysical properties data and
predictive calculation methods for the major pure components
(methane, ethane, propane, butanes, and nitrogen) of liquefied
natural gas mixtures at temperatures between 90 K and 300 K and at
pressures up to 350 bar (5000 psi). Our goal is to provide a range
and quality of data that will be recognized as definitive or standard
for all foreseeable low temperature engineering calculations.

Background . Liquefied natural gas is expected to supply an increasing
percentage of the United States' future energy requirements. It is
likely that massive quantities of liquefied natural gas will be imported
during the years 1976 - 1990. Ships and importation terminals are
being built for transporting, storing, and vaporizing liquefied natural
gas for distribution. Accurate physical and thermodynamic properties
data for compressed and liquefied natural gas mixtures are needed to
support these projects. For example, accurate compressibility and
thermodynamic properties data are needed to design and optimize
liquefaction and transport processes; accurate data for the heating
value, which for liquefied natural gas mixtures depends on the total
volume, the density, and the composition, are needed to provide a
basis for equitable custody transfer.

Accurate thermodynamic properties data for liquefied gas mixtures
must be based on precise compressibility and calorimetric measure-
ments; compressibility data give the dependence of thermodynamic
properties on pressure and density (at fixed temperatures); calori-
metric data give the dependence of thermodynamic properties on
temperature (at fixed pressures and densities). It is impossible
however, to perform enough compressibility and calorimetric
measurements directly on mult i component mixtures to permit
accurate interpolation of the data to arbitrary compositions,
temperatures and pressures. Instead, thermodynamic properties
data for multicomponent mixtures usually must be predicted
(extrapolated) from a limited number of measurements on the pure
components and their binary mixtures.

This project was initiated to provide the natural gas industry with
comprehensive accurate data for pure compressed and liquefied
methane, the most abundant component in LNG mixtures. We
have published National Bureau of Standards Technical Note 653,
"Thermophysical Properties of Methane, From 90 to 500 K at
Pressures to 700 Bar, " by Robert D. Goodwin, (April 1974). This
report contains the most comprehensive and accurate tables
available for the thermophysical properties of pure gaseous and
liquid methane, and provides an accurate basis for calculating
thermophysical properties data for LNG mixtures.

Program and Results .

7 . 1 Ethane, Thermophysical Properties Data--R. D. Goodwin .
Our major, new contribution on the thermophysical properties of the
constituents of liquefied natural gas mixtures is the publication
"Provisional Values for the Thermodynamic Functions of Ethane, "
NBS IR 74-398 (June 1, 1974). This report has been printed at NBS
in Boulder, Colorado. This work on ethane provides background on
available physical properties data, and may serve engineering needs
for thermodynamic properties until such time as new physical data
permit a revision of the tables. This report provides the first known
tabulation of the thermodynamic properties of saturated and compressed
liquid ethane at temperatures below its normxal boiling point (184.5 K).
See attached Appendix,

In additional to all of the new analytical formulations of physical
properties data, developed for the above report on ethane, we have
carried out further work on the equation of state for methane and for
ethane to obtain the simplest possible form, amenable to corresponding
states computations on mixtures. This work, "Equation of State for
Thermodynamic Properties of Fluids, " will appear in the NBS Journal

"Provisional Values for the Thermodynamic Functions of Ethane"

of Research, Vol. 79A( 1), Jan. - Feb. (1975),

Appendix

"Provisional Values for the Thermodynamic Functions of Ethane"

NBS IR 74-398 (June 1, 1974)

TABLE OF CONTENTS

Page

PREFACE vii

1. INTRODUCTION 1

2. PHYSICAL PROPERTIES AND THEIR REPRESENTATION . . 2

2.1 Fixed -Point Constants 2

2.2 Melting Line and Vapor Pressures 3

2.3 The Orthobaric Densities 5

2.4 The Virial Equation 9

2 . 5 The Equation of State 11

2.6 The Ideal Gas Functions 13

2.7 The Heats of Vaporization 14

2.8 Specific Heats for Saturated Liquid 15

2.9 Specific Heats Cp (T) along Isobar P^ 15

3. COMPUTATIONAL METHODS 16

3. 1 The Homogeneous Domain 16

3.2 The Vapor -Liquid Transition 17

3.3 Compressed Liqioid States 17

4. TESTS AND COMPARISONS 18

4.1 The P-p-T Compressibility Data 18

4.2 Calculated P(p) Critical Isotherm 19

4.3 Heats of Vaporization and Closure Computation 19

4.4 Heat Capacity for Saturated Liquid 20

4.5 Specific Heats, Cp(p,T) 20

4.6 Comparison of Enthalpies 20

4.7 Speed of Sound for Saturated Liquid 20

TABLE OF CONTENTS (Continued)

■ Page

5. TABLES OF PHYSICAL AND THERMODYNAMIC

PROPERTIES 21

5. 1 Calculated P-p-T Isochores and Isotherms 21

5.2 The Jovile -Thomson Inversion Locus 21

5.3 Thermo physical Properties of the Saturated Liquid . . 21

5.4 Thermophysical Properties along Selected Isobars. . . 21

6. COMMENTS AND RECOMMENDATIONS 21

7. ACKNOWLEDGMENTS 23

8. BIBLIOGRAPHY .• 24

APPENDIX A. Symbols and Units 31

APPENDIX B. Fixed -Point Values 32

APPENDIX C. Exposition of the Equation of State 33

APPENDIX D. Manuscript, "The Vapor Pressures of Ethane" . 35

APPENDIX E. Manuscript, "Ethane Virial Coefficients and

Saturated Vapor Densities" 58

APPENDIX F. Manuscript, "The Orthobaric Densities of

Ethane, Methane, Oxygen, and Fluorine ... 79

APPENDIX G. Manuscript, "Liquid -vapor Saturation

(orthobaric) Temperatures of Ethane

and Methane" Ill

APPENDIX H. Computer Programs for Equation of State .... 123

APPENDIX I. Computer Programs for Thermofunctions .... 142

LIST OF FIGURES

Figure 1. The locus of recent P-p-T data 159

Figure 2. Generalized locus of isochore inflection points .... 160

Figure 3. Generalized behavior of the critical isotherm .... l60

Figure 4. Generalized behavior of the locus 9(p) l6l

Figure 5. Generalized behavior of the function f(ftT) l62

TABLE OF CONTENTS (Continued)

Page

Figure 6. Generalized behavior of the function ^(ft T) l62

Figure 7. Behavior of coefficients B(^) , C(^) for methane .... 163

Figure 8. Presumed behavior of C(p) for hydrogen 164

Figure 9. Generalized density -temperature phase diagram. . . 165

Figure 10, Comparisons for saturated liquid ethane 166

Figure 11. Speeds of so\ind for saturated liquid ethane 167

7 . 2 Ethane, Compressibility (PVT) Data--G. C. Straty
In the gas expansion technique used in this laboratory for accurate,
absolute, compressibility (PVT) determinations, the molar volume
V of a cryogenic fluid contained in a cell at temperature T and
pressure P is determined by expanding the fluid from the calibrated
cell into large calibrated volumes maintained near room temperature
(~ 295 K). Using the near -ideal -gas -like behavior of the room
temperature gas, the number of moles of gas residing in the total
system can be computed accurately. One of the factors limiting the
accuracy of this method is the ability to assign correctly the
appropriate proportions of the fluid to the cell and to the various
noxious volumes elsewhere in the system,

PVT measurements on ethane present an additional problem not
encountered with most cryogenic fluids such as methane, oxygen, etc,,
because the critical temperature of ethane (305,33 K) is well above
room temperature. The consequence is that during many of the density
measurements on ethane, relatively high density fluid would reside in
external parts of the system which could not be accurately accounted
for in the present apparatus without some modifications.

During the previous period, appropriate portions of the apparatus were
enclosed in ovens and/or provided with heaters to maintain their
temperatures well above the critical temperature of ethane, Thermo -
metric sensors were calibrated and installed to these various portions
of the apparatus to enable the temperatures to be measured and accurate
PVT data obtained. Volume calibrations of several new system com-
ponents were made. Preliminary testing of the apparatus was performed
with satisfactory results.

During this reporting period, data were obtained along several
isochores of both methane and ethane. Measurements on methane
were made using the apparatus as modified for the ethane experiments
in order to check the accuracy and consistency of the data. Excellent
agreement with the methane data of Goodwin and Prydz was obtained.

Preliminary measurements on ethane revealed that some additional
modification of the apparatus and data reduction techniques would be
worthwhile in order to further increase the accuracy of vapor
pressure and density determinations. An additional heater has been
installed on the PVT cell filling capillary to be used during vapor
pressure determinations. Vapor pressures obtained with this modi-
fication are in agreement with available published data.

Data obtained along several isochores of ethane appear to be in good
agreement with available data on the compressed liquid and with the
saturated liquid densities obtained independently in this laboratory by
Haynes .

Data analysis programs are being refined as additional data on ethane
is accumulated.

7 . 3 Methane, Sound Velocity Data--G. C. Straty

The ultrasonic velocities of sound in pure saturated and compressed
fluid methane have been measured at MHz frequencies. Data have
been obtained along the saturation boundary from near the triple point
to 186 K and along several isotherms from 100 K to 300 K at pressures
up to about 34 5 bar. The sound velocity data have been combined with
the previously measured PVT data to calculate the isentropic and iso-
thermal compressibilities and the specific heat ratio Cp/C-^.
Measurements along the compressed flviid isotherms at temperatures
of 210 K and above were limited to a minimum density ranging from
about 14 mol/^ at 210 K to about 10 mol/iat 300 K due to the large
sound attenuation in methane. A manuscript reporting the results of
the ultrasonic sound velocity measurements on methane has been
published in Cryogenics, 14 , 36 7 (1974),

A light scattering spectroscopy apparatus has been employed to
obtain hypersonic (GHz) velocity data at the lower densities where
measurement by ultrasonic techniques were impossible. Data have
been obtained to densities as low as 1 mol / 1 along several isotherms.
(See the figure attached to the report on Cost Center 2750141. The
O indicate the ultrasonic measurements; the indicate the light
scattering measurements. ) Measurements in the regions of
overlap with the viltrasonic data indicate excellent agreement,
and overall agreement with calculated sound velocity data is
satisfactory. Additional, more accurate measurements are planned.

8. Problem Areas. For ethane, the computation of an accurate ther-
modynamic network in liquid states is more difficult than for methane.
Vapor pressure measurements of high accuracy are needed at low-
temperatures, where these pressures are so small that no accurate
experimental technique so far has been developed. Heats of vapori-
zation are so large at low temperatures (17, 000 j/mol) that the
experimental error of greater than 1% in these data gives about

200 J/mol error in computations across the vapor liquid "dome. "
Densities of saturated liquid ethane in the mid-range of temperatures
(160 to 250 K) apparently never have been measured. The melting
line is known only with very low accuracy and initial attempts to
measure it using the compressibility apparatus have been unsuccessful.
Comparison of our calculated speeds of sound for saturated liquid
ethane with experimental data suggests that derivatives of the
P(p, T) surface (via the equation of state) are not as accurate at low
ternperature s as desired. All of these deficiencies suggest the need
for new highly accurate compressibility (P-p-T) measurements,
sound velocity measurements in the homogeneous, single-phase
domain, and possibly additional specific heat measurements, e.g.
Cv(P, T).

As mentioned above, we have been unable to make melting line
measurements using the compressibility apparatus. It is hoped that
these measurements can be made using other existing apparatus.

9 . Funding .

Man -years expended (July -Dec. 19 74) 0.8

Equipment and/or Services Purchased 4.4 K$

Total Reporting Period Cost 63.1 K$

Balance Remaining (Dec. 31, 19 74) 56.9 K$

10. Plans for Future Work.

Objectives and Schedule:

1975

Measure compressibilities
(PVT) of liquid ethane.

Prepare report.

•

Title. DENSITIES OF LIQUEFIED NATURAL' GAS MIXTURES

■ ■ Principal Investigators . W , M. Haynes, M. J, Hiza, R. D.McCarty

2. Cost Center Numbers . 2751574, 2752574 (2751364, 2752364)

3. Sponsor . LNG Density Project Steering Committee, American Gas

Association, Inc., Project BR 50-11.

4. Introduction. Accurate density measurements and calculation
methods for liquefied natural gas mixtures are needed to provide a
basis for custody transfer agreements and for mass, density, and
heating value gauging throughout the fuel gas industry.

The basis for the custody transfer of natural gas is its heating value.
It is difficult to determine and agree on the heating value of extremely
large volumes of natural gas in the liquid state. For example, methods
for calculating the heating value of a liquefied natural gas mixture re-
quire knowing its density, which in turn depends on its composition,
temperature, and pressure. As the compositions of LNG mixtures
vary considerably, depending on the sources of the gas and the pro-
cessing conditions, accurate methods are needed for calculating
liquid densities at arbitrary compositions, temperatures and pres-
sures. The accuracy is important because of the extremely large
volumes of liquid involved.

, 5. Objectives or Goals . The objectives of this work are to perform

accurate (0. 1%) and precise (0.02%) measurements of the densities
of saturated liquid methane, ethane, propane, butanes, nitrogen and
their mixtures in the temperature range 105-140 K, and to test and
optimize methods for calculating the densities of LNG mixtures at
arbitrary compositions and temperatures.

6. Background . This project is being carried out at NBS because of
the realization that equitable custody transfer agreements could be
reached more readily if the density measurements and the evaluation
and development of calculation methods were performed by independ-
ent professionals of established reputation.

Prior to this reporting period an apparatus incorporating a magnetic
suspension technique has been developed for absolute density measure-
ments on liquids and liquid mixtures, particularly at saturation, for
temperatures between 90 and 300 K. The repeatability and estimated
precision of measurement are better than 0.02% while the accuracy is
better than 0.1%.

7. Program and Results . Saturated liquid density measurements

have been completed for the pure components of liquefied natural
mixtures in the temperature ranges as follows: (a) methane
(105-160 K), (b) ethane (100-220 K), (c) propane ( 105-1 50 K),
(d) normal butane (135-170 K), (e) isobutane (115-150 K), and
(f) nitrogen (95-120 K). The saturated liquid densities of ap-
proximately equimolar mixtures of methane + ethane and
ethane + propane have been determined in the temperature
range from 105 to 140 K.

The task of producing and testing a mathematical model which
will accurately predict the densities of LNG mixtures as a func-
tion of composition, temperature and pressure has continued
during this reporting period. Extensive effort has been directed
toward applications of the one fluid theory of corresponding
states. New computer programs have been written to optimize
the so-called "shape factor s"using the recent pure fluid data
from this laboratory. Significant improvements in the shape
factors have been obtained. The testing and optimization of
the predictive models [1-3] will continue during the next report-
ing period as new experimental data become available.

Reference s:

Albright, M. A., Technical Publication No. 3, A Report
to the Gas Processors Assoc., 1812 First Place, Tulsa,
Okla. 74103(1973).

Rodosevich, J. B. and Miller, R. C., Advances in Cryo -
genic Engineering, 1_9, 3 39 (1974).

Mollerup, J. and Rowlinson, J. S., Chemical Engineering
Science, 29, 1373 (1974).

[1]

[2]
[3]

8.
9.

10,

Problem Areas . None .

Funding .

2 751574 (measurements)

Man years expended, July-December 1974
Equipment and /or services purchased $
Total reporting period cost $

0. 8

3. 3 K
41 . 7 K

Balance remaining, December 31, 1974

$ 62. 3 K

2752574 (calculation methods)

Man years expended, July-December 1974 0.4
Equipment and /or services purchased $ 1.8 K

Total reporting period cost $ 21.7 X

Balance remaining, December 31, 1974 $ 42 . 5 K

Plans for Future Work.

year

^1 . , . T 1 T ■. quarter
Objectives and Schedule:

1975

Measure densities of binary
mixtures containing methane,
ethane, propane, butanes and
nitrogen.

Test and optimize available
calculation methods.

1. Title. Low Temperature Material Behavior

Principal Investigators . R. P. Reed, R. L. Tobler, R. P. Mikesell,
and R. L. Durcholz.

2. Cost Center Number . 2750430

3. Sponsor Project Identification . Maritime Administration Project
55-300-15-011.

4. Introduction . Data on thermal and mechanical properties of structural
and insulation materials are essential to facilitate material selection
on the basis of cost and safety. Proper material choice and reliable
definition of material behavior using fracture mechanics is of major
economic importance for cryogenic containers in the sea transport of
LNG.

5. Objectives . The objective of this program is to obtain fracture tough-
ness and fatigue crack growth rate data in the temperature range 76-
300 K. These measurements are being conducted on a series of Fe-Ni
alloys and Al alloys.

6. Background . To construct tanks for sea transport of LNG requires
between 500,000 and 7,000,000 pounds of expensive alloys, depending
on the type of tanker chosen. This large-scale consumption of costly
alloys demands very careful material selection to insure economical
but safe, storage tanks. Therefore, since MarAd's goal is to reduce
ship costs, it is in their interest to insure the availability of
relevant thermal and mechanical property data to enable the best possi-
ble material selection and dependable, efficient design.

7. Program and Results . The materials effort in this program has concen-
trated on two areas, a general materials properties assessment and the
initiation of an experimental low temperature tensile, fatigue, and
fracture study of candidate materials. The materials properties assess-
ment has included a compilation of all fatigue and fracture data on
Fe-Ni steels and their weldments, a collection of ship design data and
an analysis of materials in use, an assessment of the current production
and/or research efforts of the materials suppliers, an assessment of
the current materials requirements for LNG containers by the American
Bureau of Shipping, U. S. Coast Guard, and the ASME pressure vessel
code, and the bibliography of literature containing data on aluminum
alloys, non-metallics , and insulation materials. For the experimental
program the materials were procured; specimens were made for tensile,
fatigue and fracture tests for selected materials; a variable tempera-
ture cryostat was built; and the experimental procedures proofed, and
fracture data obtained on selected Fe-Ni alloys and alluminum alloys.

Materials Properties Assessment

The literature data from some 60 references on the fatigue and fracture
properties of the ferritic Fe-Ni steels (Ni 18%) has been extracted,

critically valuated, and compiled. The fracture data in the compilation
are the impact energy; nil ductility transition, crack opening displace-
ment, fracture toughness, and dynamic tear tests and their dependencies
on temperature, composition, and heat treating or cold working. Fatigue
data include fatigue lifetime and fatigue crack growth rates at LNG
temperatures. Also included are tensile properties, hardness, impact
energies, explosion bulge tests, and other fracture data. The entire
compilation will be sent as an interagency report and included in a
review article on LNG materials in the open literature.

The production and research capabilities of the major suppliers of LNG
structural alloys were also assessed. Direct contact was made with the
research personnel of all the major suppliers to assess what work on
these materials has been done or was in progress. These in-house efforts
indicated are generally low level. We have attended the LNG Materials
Conference at the British Welding Institute and visited Technigaz, Det
Norske Veritas, and the Welding Institute to provide information about
the foreign efforts in LNG materials research. We also have a member
of our staff on the Cryogenic Materials for LNG Tank Applications
Committee of the Metals Properties Council.

Experimental Program

Test materials of 1-1/2 inch thick plate have been obtained for the
3-1/2, 5, 6 and 9% Ni steels and Al 5083. Fe-9Ni steel has been obtained
from two sources.

A cryostat for variable temperature control near LNG temperatures was
designed and built. The experimental procedures, especially J integral
test techniques, were evaluated and proven satisfactory. New methods
were devised to monitor the crack growth and crack opening.

Fracture toughness and fatigue crack growth rate tests at 300, 195, 111,
76, and 4 K have been completed. These alloys include Fe-6Ni and Fe-
5Ni in the QLT or austenitized, temperized, and reversion annealed con-
dition, two Fe-9Ni alloys from different suppliers in the quenched and
tempered condition, and 5083 aluminum in the annealed condition.

Linear elastic fracture mechanics parameters (K^, ^-^q) J-integral
(J^^) test data have been measured for identical 1.25 inch thick com-
pact tensile specimens. For the first time valid K^^ critical stress
intensity data have been obtained for these alloys. Also, for the
first time a decided temperature dependence of the fatigue crack growth
rate in Fe-Ni body centered cubic alloys has been measured; the rate
of crack propagation is higher at 67 K compared to room temperature
for all alloys. For 5083 aluminum, however, the fatigue crack growth
rate decreases at lower temperatures.

Program Publications and Talks

One paper has been Included in the Special Technical Publication of the

ASTM conference, "Low Temperature Fracture Behavior of Ferritic Fe-Ni
Alloy Steels," by R. L. Tobler, et al.

Problem Areas . Testing has proceeded on schedule. There are no
delays .

Funding . During this reporting period, about 540,000 has been spent.
This completes research for the program described.

Future Plans . During the next six months the fatigue and fracture
toughness properties of welded Fe-5Ni steel will be measured at 300,
195, 111, and 76 K.

Title . Program for Reducing the Cost of LNG Ship Hull
Construction

Principal Investigators . H. I. McHenry, M. B. Kasen and

R. P. Reed

Cost Center Number . 2751430

Sponsor Project Identification. Maritime Administration

Project 400-58073

Introduction. Construction of LNG tankers requires the use of
fine grain normalized steels for the part of the hull structure
that is cooled by the cargo to temperatures in the range of 0 to
-50° F. Several ABS steels have satisfactory base plate pro-
perties but extreme care must be exercised during v^elding to
avoid degradation of the steel adjacent to v^^eld (the heat affected
zone) to a level of toughness below U. S. Coast Guard require-
ments. Significant cost problems are being encountered by
U. S. shipyards due to the resulting inefficient low-heat-input
welding procedures that must be employed to meet the fracture
requirements in the heat affected zone.

Objective . The objective of the current program is to survey
the feasability of developing, evaluating and qualifying a ship
steel that permits more efficient welding practices and retains
satisfactory low-temperature fracture behavior.

Background . Early in 1974, the Welding Panel of MarAd's
Ship Production Committee recommended that a program be
conducted to reduce the cost of ship hull construction. NBS
was requested by MarAd to propose such a program to the
LNG subcommittee of the Welding Panel at a meeting in Boulder
in August. In mid-October, MarAd approved the initial phase
of NBS's recommended program, i. e. to survey the problem
and the technology available for it's solution. On the basis of
this survey a coordinated program involving the LNG shipyards,
the steel suppliers and NBS will be planned and recommended
to MarAd and to the Welding Panel in the first quarter of 1975.

Program and Results. The survey of the feasability of reducing
the cost of LNG ship hull construction consisted of four distinct
tasks :

1. Visit the shipyards to properly define the problem.

2. Visit the regulatory agencies to define the -limits
that we must work within.

3, Visit the steel companies to assess the technology-
available to solve the problem,

4. Survey the technical literature.

Significant progress has been made on each of these tasks during
the reporting period.

The four U. S. shipyards with contracts to build LNG tankers
were visited:

Avondale Shipyards, Inc. , New Orleans, LA.
General Dynamics, Quincy Shipbuilding Div, , Quincy, MA.
Newport News Shipbuilding and Dry Dock Co. , Newport
News, VA.

Sun Shipbuilding and Dry Dock Co, , Chester, PA.

At each shipyard, the design and fabrication of the LNG ships
were reviewed and the problems associated with welding of the
ship plates for the low temperature (0 to -50° F) portion of the
ship were discussed. The overall conclusion of these visits
was that productivity was limited by the weldability of the base
metal. Thus, the program should be directed towards improving
the base metal--as opposed to improving the welding procedures
or the consummables such as fluxes, rods and wires.

Visits were made to the two regulatory agencies that control the
construction of LNG tankers in the U. S. : the American Bureau of
Shipping (ABS) and the U. S. Coast Guard (USCG). Their view-
points of the requirements on the properties required in the steel
weldments were solicited. ABS indicated that the requirements
might be unrealistictly severe and favored a program that would
lead to the establishment of more rational requirements. The
USCG emphasized the permanence of the standards as they cur-
rently exist because of the international acceptance of the require-
ments as they stand. The conclusion of these visits was that the
program to develop an improved ship steel should be conducted
using the current requirements as the property goals; however,
parallel program to evaluate the rationality of these requirements
should be formulated in conjunction with ABS.

The four leading steel plate producers and two other companies
were visited to assess the applicable steel making technology:

Armco Steel Co. Middletown, OH.

Bethlehem Steel Co. Bethlehem, PA.

Lukens Steel Co, Coatesville, PA.

U. S. Steel Co. Monroeville, PA.

Linde Division of Union Carbide Ashtabula, OH.
Climax Molybdenum Co. Ann Arbor, MI.

At each steel company, an overview of the MarAd program was
given by NBS»and the steel companies reviewed their experience
with low temperature steels and advised NBS on the technology
available to provide ship plate with improved low temperature
toughness in the heat affected zone. The conclusions of these
visits were that the most promising steel making practices
were sulfide shape control and columbium treated steels. In
addition, the advisability of purchasing steels to guaranteed
transverse toughness requirements was emphasized.

A literature search is being conducted to further assess the tech-
nology available to improve ship steels. The basis for this search
was bibliographies obtained from DDC, NTIS and the American
Society of Metals. This task is still in progress and will be re-
ported on in the next issue of this document.

Problem Areas. None

Funding. Cost to 12/31 /74 $10,000

Balance 25,000

Future Plans. The results of our survey will form the basis of
a program to be formulated and recommended to MarAd on
February 12, 1975. Approxirm tely one month later, the program
will be presented to the MarAd Welding Panel for their considera-
tion.

1. Title . Heating Value of Flowing LNG

Principal Investigators . J. A. Brennan and J. M. Arvidson

2. Cost Center Number . 2756579

3. Sponsor Project Identification . Pipeline Research Committee (American
Gas Association) PR-50-48

4. Introduction . This project will draw on information and facilities
generated by other sectors of the NBS LNG effort. Thus the calibration
of a densimeter used will be traceable to the NBS density reference
system being constructed by Younglove under cost center 2751361.
Mixture density data produced under 2751574 by Haynes and Hiza will also
provide a necessary input to the proper interpretation of results.

5. Objectives . The original objective of this program was to set up a LNG
flow facility and to evaluate selected flowmeters in LNG service. In
November 1973 the objective was expanded to demonstrate the accuracy

of measurement of the heating value of LNG flowing in a pipeline through
integration of state-of-the-art instrumentation for flow, density and
heating value. The expanded project has been conceived of in a three-
year time frame. In the first year individual components will be cali-
brated and installed in the NBS LNG flow facility.

6. Background . The need for accurate flowmetering of LNG provided the
original impetus for the work in this program (unpublished NBS Report
[1972], NBSIR 73-300). Since liquid natural gas may be sold on the
basis of heating value the program was broadened to include the neces-
sary instrumentation for determining heating value of LNG, this ex-
panded program to commence early in 1974. The objectives are based on
scaling small flowmeters capable of laboratory testing up to full line
size components. Appropriate intermediate sizes are included with field
tests scheduled as part of the overall project.

7. Results . Liquid nitrogen tests on both four-inch vortex shedding flow-
meters referred to in the last report [NBSIR 74-373] have been com-
pleted. One of the meters was installed in a test section and sent to
an LNG facility for installation preparatory to conducting the LNG tests.
These tests were originally scheduled to be completed in 1974 but have
had to be rescheduled for early in 1975.

The orifice meter used in the gas phase measurement at the LNG facility
was calibrated in water at the NBS flow facility in Gaithersburg, Mary-
land. This calibration will help in determining the actual orifice
flow coefficient which will be used in comparing the liquid measurement
with the vaporized gas measurement.

Refurbishing of the surplus calorimeter has been completed. The calo-
rimeter and the gravitometer have been connected to the flow facility
and are now operational.

Problem Areas . No problem areas have been encountered that would
have an adverse effect on the project.

Funding .

Man Years Expended 1.25

Major Equipment Purchased $ 8,000

Total Reporting Period Costs 73,000

Balance on Hand 26,000

Future Tests . The flowmeter tests at an LNG peak shaving plant are
now planned for early 1975. The next phase of the flowmeter scaling
will be started after the LNG tests. Tests of the NBS integrated flow
facility will also be started in early 1975.

1. Title . LNG Density Reference System.

Principal Investigator . Ben Younglove

2. Cost Center Number . 2751361

3. Sponsor Project Identification . American Gas Association, Inc.
Project BR-50-10.

4. Introduction . The emphasis of the LNG effort of NBS is in providing
technical support to industry in meeting the energy needs of our
economy with natural gas.

The density reference system will evaluate the ability of com-
mercially available instruments to measure densities of LNG. Density
is an essential measurement in performing total energy content deter-
minations of natural gas reservoirs. While this effort is oriented
towards metrology, the output from cost center 2751574 will provide
basic reference data on pure liquids and mixtures which will serve as
density standards.

5. Obj ectives . This research will provide a system for evaluating the
density measurement capability of commercially available meters. We
will evolve a density reference system capable of generating accurate
densities for this evaluation. From the commercial meters we will
attempt to select one capable of performance as a transfer standard in
order to provide traceability of accuracy to field density measurement
systems.

The first year will be devoted to construction and testing of the
density reference system. In the second year we will concentrate on
evaluation of commercial meters, while the final year will involve
selection testing and application of the transfer standard.

6. Background . In early 1973 a proposal was made to the American Gas
Association for research in several areas of LNG technology to be done
at this installation. Part of this program was the density reference
system. Initial scheduling indicated for the first year of work, starting
in April, to be design, fabrication, and testing of a density system.
Work actually commenced in August as a result of staffing difficulties.
Since this initiation, we have conducted extensive study on the
feasibility of various techniques for such a system, deciding finally

on an application of Archimede's principle (see 7. below). The reference
system is now in the latter stages of construction and evaluation.

7. Program and Results . Vibrating cylinder and vibrating plate densimeters
have been received and installed in the test apparatus. An additional
vibrating cylinder device has been withdrawn from the test program due
to vibrating instabilities. The capacitance meter is ready for delivery
and will arrive on commencement of the liquid nitrogen test.

There is some uncertainty regarding the delivery of the magnetic
buoy device. We will be advised on this soon by the manufacturer.

A microwave cavity is being modified for installation and evalu-
ation; this is an NBS device. We also are assembling a vibrating
hollow-tube densimeter for evaluation.

The vibrating plate device has been checked in distilled water,
also alcohol, acetone, hexane and in air as a preliminary evaluation
and pre-calibration at room temperature. The vibrating cylinder
densimeter was checked in liquid nitrogen in a similar test. No mal-
functions were noted.

The capacitance device was checked in liquid nitrogen on its first
arrival and showed reasonable behavior but suffered from an intermittent
open circuit. The device was returned to the manufacturer for inspec-
tion. The electronic read-out unit was replaced by a more up-to-date
version.

The weighing head has arrived in this reporting period and has
shown some malfunctioning in the electronics. The weight loader is
being rebuilt as the initial design was too position sensitive. The
density monitor device has been checked in distilled water.

It is expected that the density reference system will be oper-
ational by 15 February 1975 and that significant testing can be initiated
at that time. Preliminary considerations have been made concerning
statistical test procedures.

8. Problem Areas . The weighing head had several malfunctions including
an unintentional short to ground in the sensing circuit and improperly
installed knife edge. One vibrating cylinder device and possibly the
magnetic buoy may not be available for test; the magnetic buoy system
is large enough to require separate testing from the other transducers.

9. Funding . July 1 - December 31, 1974.

Man-Years this period:

Principal 0.42

Technician 0.16

Equipment $ 550

Total Cost 31,700

Balance on hand end December 24,500

10. Future Plans . First three months. Check monitor performance using

liquid nitrogen and methane. Run tests on assembled densimeters using
binary mixtures of methane with ethane, propane, and butane. Develop
a statistical test plan in cooperation with the NBS statistical group.

Second three months. Complete binary bests and conduct tests on
more complex mixtures according to the test plan. Initiate the pre-
liminary tests on the magnetic buoy device depending on its availability
and the scheduling of the above tests.

1. Title . Liquefied Natural Gas Technology Transfer
Principal Investigator . D. B. Mann, R. S. Collier

2. Cost Center Number . 2750401

3. Sponsor Project Identification . Maritime Administration, Project
55-330-15-011.

4. Introduction . The NBS support of the Maritime Administration (MarAd)
LNG ship program is divided into two areas. These are a materials
experimental program (Cost Center 2750430) and cryogenic technology
transfer. In addition to those objectives listed below this program
provides a cohesive structure for the coordination of the NBS LNG
program.

5. Objectives . Cryogenic Technology Transfer is designed to provide
cryogenic technical information, data, and advice to the Maritime
Administration (MarAd) , its contractors and other agencies performing
work of interest to, or for, MarAd in the design, development, testing,
construction and^operation of LNG ships and ship components.

6. Background . The Merchant Marine Act of 1970 restructured federal
maritime policies to make bulk carrier vessels, such as tankers and
LNG ships, eligible for construction and operating subsidies. In
December 1973 the keel was laid for a 926 foot long LNG vessel carrier
at Quincy, Mass. The keel laying initiated the construction of the
first LNG tanker to be built in the United States. American ship
builders have orders for a total of 15 of these complicated ships.
Various future projections indicate a total of from 25 to well over

a 100 ships will be required to handle the LNG importation within the
next 10-15 years. LNG marine technology is presently foreign dominated
As a matter of fact, many of the ships being constructed in U. S. ship-
yards are using designs under license from foreign industrial groups
or governments. LNG is a cryogenic fluid and the massive technology
developed over the past 15-20 years in cryogenics as applied to indus-
trial gases and the aerospace effort provides a resource which could
be applied profitably to improving the U. S. competitive position in
the construction and operation of LNG shipping. Because of its
historical association with broad based cryogenic technology over a
period of 20 years, the NBS Cryogenics Division was requested to pro-
vide support to the MarAd LNG ships program in order to aid in the
transfer of cryogenic technology where it could enhance the effective-
ness of maritime LNG shipping. Therefore, on April 17, 1973 we sub-
mitted a work statement which was confirmed by the establishment of a
program in May.

7. Program and Results . In the initial phases of the LNG Cryogenic Tech-
nology Transfer Program emphasis was placed on establishing the level
and degree to which we could interface with MarAd, MarAd Research

Centers and MarAd contractors. Progress, therefore, Is measured as
specific responses to MarAd and MarAd contract requests and NBS
generated output felt necessary for the overall program,

7.1. Data and Information — LNG . Thermophysical property data and
measurement methods for LNG are necessary for design and performance
evaluations of major structural ship containment systems, insulation
and major components such as valves, piping, pumps and safety oriented
and operational instrumentation. This data is also necessary to es-
tablish ship operational efficiencies by accurately relating the
volume of LNG carried to the actual quality of the LNG as a fuel —
its heating value. This latter quantity is the contract designation
which the ship owner or operator is obligated to establish both on
purchase and delivery of the cargo.

Thermophysical property data and related measurement methods must
be of high accuracy and precision and the information must be put in
the hands of those who need it. This information must be accepted for
its validity on an international basis, but with emphasis on first
availability to U. S. maritime industry.

Emphasis during this reporting period has been to establish the
necessary mechanism for acceptance of previously generated data as well
as the results of current research. The thermophysical properties of
methane (see AGA project BR-50-10, cost center 2750364) generated under
the NBS program have been accepted and approved by the three AGA stand-
ing committees charged with LNG responsibilities. In addition, the
data has been submitted as an ASTM standard by NBS and will be recom-
mended as an ANSI standard by the AGA. Other data on ethane, propane,
butane, and nitrogen and their mixtures (LNG) will follow this
procedure (see AGA project BR-50-11, cost center 2751574, 2752574).

Measurement methods to establish cargo value are also being estab-
lished (see AGA project PR-50-48 and paragraph 7.2 below) and will be
submitted to shipbuilders, owners and operators for their comments and
approval.

Additional methods of disseminating cryogenic technology are also
being explored. The American Bureau of Shipping (ABS) was visited in
November of 1974. The ABS is a ship classification society which es-
tablishes standards known as "Rules" for the design, construction and
periodic survey of ships and other marine structures. Classification
certifies adherence to these rules providing assurance that a vessel
posseses the structural and mechanical fitness for its intended service.
The visit by NBS personnel was at the request of ABS staff for the pre-
sentation of the total NBS LNG program with particular emphasis on
materials of construction information. We will continue to provide
them with program information and ABS will certainly be closely associ-
ated with the ships hull material study (cost center 2751430).

7.2. LNG Custody Transfer Systems . As part of a program to provide
information and assistance to the shipbuilding companies of the United
States, NBS was requested to give an independent evaluation of custody
transfer systems for ships designated by MA Design LG8-S-102a MA Hulls
289, 290, 291.

In general, the scope of work for system component evaluation in-
cludes transducers and instrumentation for liquid level, density, tem-
perature and pressure, and also the sampling of mole fractions of LNG
components; advanced techniques may include direct measurements of the
total mass and the total potential heat of combustion of the fluid
(heating value or "therm" metering) .

In addition to design and evaluation of system components (which
would possibly be common to several different types of systems), there
is a need to consider the integration of these components into a custody
transfer system. This may require knowledge of the system independent
of instrumentation. For example, tank capacity tables relating liquid
level to liquid volume rely on the accuracy of survey procedures for
measuring the inside tank dimensions, also on calculations of list and
trim corrections, the effect of thermal contractions, and tank loading
factors. Also, since LNG is a mixture, there is normally a selective
vaporization of the fluid causing space and time variations of the fluid
mixture and its properties (tank "weathering") . These effects extend
the conditions under which sensors and transducers must operate.

As part of Phase I of this evaluation (System Design Review) NBS
has received from the ship contractors and builders information, plans,
and drawings regarding the following:

1) Overall layout of the ship tank and piping system.

2) Basic tank construction materials.

3) Drawings and information on the locations and use of Resistance
Thermometer Devices (RTD's).

4) Preliminary drawings and block diagrams concerning the capaci-
tance liquid level and density measuring devices.

5) An error analysis of tank measurements using conventional strap-
ping techniques.

6) Information on the probable range of LNG mixture constituent
fractions .

In addition, informal discussions have been held with the ship-
builder, owner and subcontractors concerning the capacitance level
measurement, heat leak and convective patterns within the tank, ship
operating procedures, possible new tanks trapping procedures, potential
heat of combustion (heating value) and its measurement, and alternate
(future state of the art) gauging techniques.

Using this and other sources of information NBS has completed the
following:

1) Calculated the changes in dimensions of the tank due to thermal
contractions and tank loading.

2) Made preliminary calculations of heat transfer and system ther-
modynamics concerning the spacial and time variations of LNG
mixture fractions (tank weathering) .

3) Completed preliminary evaluation of the capacitance level and
density measurement techniques.

4) Conducted a detailed evaluation of the relationship between dielec-
tric constant and density using the relevant range of mixture
fractions and current (provisional) equations of state.

5) Reviewed various tank strapping procedures.

Based on these studies NBS has identified the following major
sources of uncertainty:

1) A non-unique relationship between dielectric constant and density.

2) Measurement of tank inside dimensions (tank strapping).

3) Possible density variations within the tank.

The systematic uncertainties for these factors are estimated as
follows:

1) Density - ±1.2% or less; this nijmber may be reduced if thermo-
dynamic conditions in the tank are known and mixture constituent
fraction data is applied as a correction factor. Technical details
of these considerations will be contained in a separate report.

2) Tank strapping - ±0.4% or less depending on the surveying tech-
nique used.

3) Non-uniform density - it is not possible to give a good estimate
of this uncertainty at the present time, some calculations show
that this effect is negligible but more work should be done in the
area of heat transfer and convective patterns of fluid within the
tank.

The uncertainty estimate for the total mass will be at least the
r.m.s. value of these three factors. Other factors mentioned above
are considered small or calculable-and-correctable. Uncertainties in
liquid level and density output, electronic signal conditioning, and
readout have not been calculated and are considered to be relatively
small at the present time; more information on this point is needed
and could possibly be considered as part of a testing program.

If the problem of tank strapping is solved the ultimate (least
possible) uncertainty will most probably rest on fluid sampling and
the resulting measurement of mixture fraction; possible non-uniform

density within the tank and liquid level measurement may also be a
factor. Thermometry may also become an important factor if mixture
constituent fraction is not well known or if density is not measured
directly.

A testing program to verify this design review is suggested as
follows:

1) A complete rangeability test of the capacitance densitometer in
the LNG density reference system over the operating ranges of
temperature, pressure, and mixture constituent fractions.

2) A test of the capacitance liquid level vernier in a convenient
LNG test facility.

3) An independent check of the strapping technique which is ultimately
decided upon.

4) Instrumentation of at least one of the tanks in operation, to
measure possible density variations within the tank.

In addition, an experimental program should be conducted to develop
gauging techniques which are less sensitive to tank strapping and possi-
ble fluid variations within the tank; e.g., RF gauging (see NBSIR 73-
346) and the strain gage technique proposed by General Dynamics. Possi-
ble direct measurements of potential heats of combustion (heating value
or "therm" metering) should also be considered.

8. Problem Areas . None.

9. Funding .

July 1 - December 31, 1974
Labor
Costs
Balance

.6 m

$42,000

10. Future Plans . A preliminary work statement has been submitted to
MarAd for continuation of this program in the areas of cryogenic
technology transfer, a study of cryogenic custody transfer systems
(2750401), and the completion of the materials experimental program
(2750430). Particular emphasis will be on maintaining present methods
of information dissemination and establishing new contacts with such
groups as the coast guard and additional shipbuilders.

1. Title . Federal Power Commission Consultation
Principal Investigators . D. B. Chelton and A. F. Schmidt

2. Cost Center Number . 2750404

3. Sponsor . Federal Power Commission - Bureau of Natural Gas — letter
agreement dated 4 June 1973.

4. Goals . The Cryogenics Division will provide consultation and advisory-
services to the Federal Power Commission on the cryogenic safety and
the design aspects of several current applications before the FPC

for authorization of LNG terminal and storage facilities. These
services cover properties of cryogenic environments, insulation sys-
tems, cryogenic safety, thermodynamics, heat transfer, instrumentation
and cryogenic processes such as refrigeration and liquefaction.

5. Background . Cost Center initiated July 7, 1973.

6. Program and Results . The results and status of those facilities pre-
sently under the jurisdiction of the Federal Power Commission and sub-
ject to our review are outlined in the following table.

Elements of the facilities that are subject to review are the land-
based cryogenic storage tank components, bounded by the tanker or barge,
the vaporizer and the liquefaction units (if any). These include, but
are not limited to the transfer lines, the storage tanks, the vaporizers
and the process piping as it interacts with the storage tanks. It is
essential that the reviews cover the operation, maintenance and emergency
procedural philosophies for each terminal. Based upon these studies,
reports are submitted to the staff of the FPC setting forth the tech-
nical evaluations and conclusions on each proposal. In addition, NBS
may provide expert witnesses on behalf of the staff of the FPC in any
hearings on the aforementioned applications.

Emphasis is placed on the safety aspects of the facilities including
their possible interactions with the surrounding areas. The impact of
engineering design such as appropriate use of existing technology and
material selection for structural integrity must be assessed. The
basis of review includes various codes and standards, prior experience,
precedent and engineering knowledge.

7 . Funding .

8. Future Plans . At the present time there are several pending appli-
cations, but detailed information is not yet available. It is antici-
pated that additional facilities will be reviewed as applications are
made to the Federal Power Commission.

Funding FY 75

July 1 - December 31, 1974
Anticipated Man Years of Effort FY 75

$50,000
14,000

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1. Title . LNG - Dual Fuel Auto

Principal Investigator . J. M. Arvidson, J. Hord and D. B. Mann

2. Cost Center Number . 2750590 (Reimbursable), 2750154

3. Sponsor Identification . Joint NBS and General Services Administration
Requisition Number F4KE023, Case Number 66551.

4. Introduction . The work described relates to the general area of
transfer of technology based on Division experience in the handling
of liquefied combustible gases, instrumentation and systems analysis.

5. Objectives . To establish the degree of hazard to passengers and auto
on the release of liquefied natural gas in the trunk area of the
standard GSA dual fuel (natural gas and gasoline) sedan.

6. Background . The General Services Administration (GSA) dual fuel auto-
mobiles are equipped to run on gasoline or natural gas. In the initial
GSA program the natural gas was compressed and carried in high pressure
cylinders, which in sedans were located in the trunk space. To take
care of accidental leakage, a large vent was installed in the roof of
the passenger compartments, with two small air vents installed in the
top of the trunk space. More recently, most of the dual fuel installa-
tions have been installed with liquefied natural gas (LNG) carried in
an insulated tank at low pressure in the trunk compartment.

Natural gas has a density less than air and therefore is buoyant
and will rise at temperatures above about 151 K. It was anticipated
that vents provided would be adequate for dilution of explosive con-
centrations of methane gas in the trunk and passenger compartments
under conditions of operation. This was believed to be the case even
if very cold gas was vented (at a temperature of less than 157 K) as
the amount of the methane gas vented at this lower temperature would
be minimal, would be heated rapidly above 157 K and then vented nor-
mally.

A recent explosion of a sedan, believed to be caused by migration
of methane gas from a trunk area to the passenger area, raised the
question of functional adequacy of the high level vents. In other
words, can a combustible mixture of cold methane gas (at a temperature
of less than 157 K) migrate from a leakage area in the trunk to the
passenger compartment, and if so, can additional venting, relocation
of vents, or other methods be incorporated in the sedan to eliminate
this hazardous situation?

GSA has requested the Cryogenics Division of NBS to perform tests,
analyze data, and make recommendations for the modification (if any)
to be made in the vent system or any other aspect, method or design
that would minimize the concentration of methane gas (or LNG vapor)
in the trunk or passenger area to well below the lower explosion limit
(at least to 50% LEL) .

A test program and results were described in the previous re-
porting period (NBSIR 74-358) . The potentially hazardous condition
caused by release of methane or vaporized LNG in the trunk area was
reported to the co-sponsor in the form of a progress report.

Program and Results . During this reporting period the General Services
Administration concluded that the work done here on the venting of the
GSA auto was adequate for their needs and that they did not intend to
pursue the subject further. TThile these decisions were being made, NBS
had requested use of the sedan for additional NBS experiments concerned
with the venting of hydrogen in addition to methane gas.

These new tests were designed to add to the information previously
collected and to answer the following questions:

a) ^'That are reasonable inflow (leakage) rates, cumulative leakage
quantities and leakage injection locations?;

b) \^at are experimentally reasonable gas residence times in the pas-
senger compartment?;

c) \'}hat is the effect of increased roof vent area?;

d) ^-That is the effect of leakage gas temperature and environmental
temperature on test results?;

e) I-Jhat is the effect of wind direction and velocity on the rate of
efflux of gaseous fuels from the car interior?; and

f) \\Tiat instrumentation is required?

The test vehicle was relocated into a test bay of a metal building
equipped with explosion proof electrical fixtures and a roof mounted
explosion proof exhaust fan. In place solid state combustible gas sensors
were substituted for sample lines used in the previous test. Tempera-
tures and pressures inside the vehicle were monitored as well as flow
rates of combustible gas introduced to the passenger compartment. Both
hydrogen and methane gas were injected into the passenger compartment.

A series of experiments were then performed to identify the explosioi
hazards, establish venting criteria, and obviate general safeguards for
hydrogen or methane fueled passenger vehicles.

It was found that appropriately designed ventilation systems sig-
nificantly reduced the safety hazards associated with accumulated com-
bustible gases. Vents were recommended for all autos converted to burn
hydrogen or methane and may possibly be eliminated in new cars that are
designed for gaseous fuel operation. Combustible gas warning systems
are recommended, at least in the interim, for all (converted and new
design) gaseous fueled vehicles. Hydrogen and methane gases appear
equally safe as vehicular fuels if used in properly designed vehicles.

The information developed under the joint OTS-GSA program has been
compiled and will be published as an NBS report (TN 666) .

This study indicates that gasoline powered vehicles converted to
burn gaseous fuel should be equipped as follows:

1) The fuel system should be adequately designed for fuel contain-
ment in the event of collision;

2) The car trunk should be adequately vented if the fuel tank is
located in the trunk;

3) The fuel tank vent should be ducted to the far rear exterior of
the vehicle;

4) A trunk membrane should be provided to isolate the trunk or fuel
and passenger compartments.

Optional but highly desirable equipment for such vehicles would in-
clude a positive ventilation system and an early warning combustible gas
detector. Guidelines for the design of appropriate ventilation systems
are given in the report. If used, a combustible gas sensor should be
located in the passenger compartment at the highest point of the roof
(vented or nonvented) .

Problem Areas . None.

Funding .

Labor .5 MY

Cost (includes some equipment) $30,000

Future Plans . The program will be terminated with the publication of
the NBS Technical Note.

NBS-1J4A (REV. 7-73)

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA
SHEET

1. PUBLICATION OR REPORT NO.

NBSIR 75-802

2. Gov't Accession
No.

3. Recipient's Accession No.

4. TITLE AND SUBTITLE

Liquefied Natural Gas Research at the National
Bureau of Standards

5. Publication Date

January 1975

6. Performing Organization Code

7. AUTHOR(S)
u» D • nann ^Hiuiuor^

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS
DEPARTMENT OF COMMERCE
WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No.

2750401

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

Same as Item 9.

13. Type of Report & Period
Covered

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant
bibliography or literature survey, mention it here.)

Eighteen cost centers supported by seven other agency sponsors in addition to NBS
provide the basis for liquefied natural gas (LNG) research at NBS. During this six
month reporting period the level of effort was at an 18 man-year level with funding
expenditures of over $485,000. This integrated progress report to be issued in
January and July is designed to:

1) Provide all sponsoring agencies with a semi-annual and annual report on
the activities of their individual programs.

2) Inform all sponsoring agencies on related research being conducted at the
Cryogenics Division of NBS-IBS.

3) Provide a uniform reporting procedure which should maintain and improve
communication while minimizing the time, effort and paperwork at the cost '

center level. '

The contents of this report will augment the quarterly progress meetings of some
sponsors, but will not necessarily replace such meetings. Distribution of this docu-
ment is limited and intended primarily for the supporting agencies. Data or other
information must be considered preliminary, subject to change and unpublished; and
therefore not for citation in the open literature .

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper
name; separated by semicolons )

Cryogenic; liquefied natural gas; measurement; methane; properties; research.

18. AVAILABILITY | | Unlimited

19. SECURITY CLASS
(THIS REPORT)

21. NO. OF PAGES

For Official Distribution. Do Not Release

to NTIS

UNCLASSIFIED

1 1 Order From Sup. of Doc, U.S. Government
Washington. D.C. 20402. SD Cat. No. C13

Printing

Office

20. SECURITY CLASS
(THIS PAGE)

22. Price

1 1 Order From National Technical Information
Springfield, Virginia 22151

Service

(NTIS)

UNCLASSIFIED

USCOMM-DC 29042-P7

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