;OPY NBSIR 75-817 e^

7 )

LIQUEFIED NATURAL GAS RESEARCH

at the

NATIONAL BUREAU OF STANDARDS

PROGRESS REPORT FOR THE PERIOD

1 JANUARY - 30 JUNE, 1975

D. B. Mann, Editor Ml

il

CRYOGENICS DIVISION • N BS— INSTITUTE FOR BASIC STANDARDS • BOULDER, COLORADO

NBSIR 75-817

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 January - 30 June, 1975

U.S. DEPARTMENT OF COMMERCE, Rogers C. B. Morton, Secretary

John K. Tabor, Under Secretary

Dr. Betsy Ancke r-Johnson , Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director

at the
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

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

U. S. Department of Commerce

National Bureau of Standards

Office of Energy Conservation

Washington, DC 20234

Aerospace Safety Research and Data Institute

National Aeronautics and Space Administration

Lewis Research Center

Cleveland, Ohio 44135

ii
ABSTRACT

Nineteen cost centers supported by six other agency sponsors in

addition fo 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 $500,000. 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 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 meetings 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 preliminary, 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

Cost Center Page

I. REFERENCE DATA

a)

b)

c)

d)

e)

f)

g)

h)

i)

SURVEY OF CURRENT LITERATURE ON LNG 2750362

AND METHANE (American Gas Association,

Inc.)

LNG FUELS SAFETY 2750427

(NASA-Aerospace Safety and Data Institute)

THERMOPHYSICAL PROPERTIES DATA FOR PURE 2750574

COMPONENTS OF LNG MIXTURES (American (2750364)

Gas Association, Inc.)

PROPERTIES OF CRYOGENIC FLUIDS

(NBS)

2750141

FLUID TRANSPORT PROPERTIES 2750124

(NBS-Office of Standard Reference Data)

PROPERTIES OF CRYOGENIC FLUID MIXTURES

(NBS; NBS-Office of Standard Reference

Data)

DENSITIES OF LIQUEFIED NATURAL GAS MIXTURES (LNG Density Consortium of 18

energy companies - AGA)

LOW TEMPERTURE MATERIAL BEHAVIOR

(Maritime Administration)

PROGRAM FOR REDUCING THE COST OF LNG

SHIP HULL CONSTRUCTION — PHASE II

SHIP STEEL IMPROVEMENT PROGRAM (Maritime Administration)

II. MEASUREMENT SCIENCE

a) CUSTODY TRANSFER - LNG SHIPS

(Maritime Administration)

b) HEATING VALUE OF FLOWING LNG (Pipeline

Research Committee - AGA)

c) LNG DENSITY REFERENCE SYSTEM

(American Gas Association, Inc.)

2750142

and

2750145

2751574

and

2752574

2750430

2751430

2752430

2753430

2750460

2756579

2751361

11

15

17

21

25

27

29

31

33

v
Contents (continued)

III. TECHNOLOGY TRANSFER

a) LIQUEFIED NATURAL GAS TECHNOLOGY

TRANSFER (Maritime Administration)

b) ENERGY CONSERVATION POTENTIAL IN THE

LNG INDUSTRY (NBS-Office of Energy

Conservation)

c) FEDERAL POWER COMMISSION CONSULTATION

(FPC)

Cost Center Page

2750401 35

2750103 37

2750404 41

vi
1. Title. SURVEY OF CURRENT LITERATURE ON LNG AND METHANE

Principal Investigator . Neil A. Olien

2. Cost Center Number . 2750362

3. Sponsor Project Identification . American Gas Association Project

BR-50-10.

4. 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 throughout

the world in the LNG field. This project is designed to provide the

Current Awareness and other information services to allow workers to keep

abreast of new research and other developments

.

5. 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 companies and

be made available to the general public on a subscription basis. In

addition, LNG related information will be entered into the Cryogenic Data

Center's Information System for quick retrieval. A continuing 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.

6. Background . In 1969 we made a thorough review of the world's publications

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 hydrogen as a future fuel. Much of this

information is also pertinent to LNG and as such is listed in our LNGrelated publications. Our Current Awareness Service has been published

weekly since 1964 (beginning in 1975 the publication became biweekly) and

the Liquefied Natural Gas Survey has been published quarterly since 1970.

7. Program and Results . Two issues of the LNG Quarterly were prepared and

distributed. There are now 120 subscriptions going to AGA Member

Companies and 148 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 January 1975.

B-1262 THE THERMOPHYS I CAL PROPERTIES OF METHANE AND DEUTERO-METHANES

IN THE SOLID, LIQUID AND GASEOUS PHASES - A SELECTED BIBLIOGRAPHY.

Indexed by property, phase and author, 68 pages (Feb 1975).

($8.00)

B-1263 THE THERMOPHYSICAL PROPERTIES OF METHANE MIXTURES - A SELECTED

BIBLIOGRAPHY. Indexed by property, system and author, 118 pages

(Feb 1975). ($10.00)

B-1264 PROCESSES AND EQUIPMENT INVOLVING LIQUEFIED NATURAL GAS AND

METHANE - A SELECTED BIBLIOGRAPHY. Indexed by subject and

author, 76 pages (Feb 1975). ($8.00)

During the period January through June 1975, we have distributed 20 copies

of these and the comprehensive bibliographies. A bibliography on LNG

Patents was supplied to AGA in May. A supplement to this is in preparation and will be completed in July.

8. Problem Areas . We have no problem areas at this time.

9. Funding . January 1 - June 30, 1975

Labor 7.3 K$

Other Costs 3.2 K$

Total 10.5 K$

Remaining 10.0 K$

10. Future Plans . Issue 75-2 of the LNG Quarterly was mailed to the

National Technical Information Service for printing and distribution on July 2, 1975. Issue 75-3 will be published in October. The three

comprehensive bibliographies discussed in Item 7 above are available for

distribution.

Jul. Aug. Sep. Oct. Nov. Dec

.

Search of Current Literature

Preparation of Issue 75-3

Preparation of Issue 75-4

»

>

*

2
i. 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

Administration, Cleveland, Ohio, Aerospace Safety Research and

Data Institute. Order No. C-39327-C.

4. Introduction . The NASA-Aerospace Safety Research and Data Institute

(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 f act, 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 references 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 safetyrelated 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 seeminly unrelated programs.

3
7. Program and Results . Under this and another ASRDI-funded program we

have started a major review of the indexing and retrieval terminology

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 fo rm. Publication has been delayed awaiting

a decision as to publishing the thesaurus separately or combined with one

in fire safety and one in the mechanics of structural failure. Most of

the terminology unique to LNG safety is now incorporated into this

thesaurus

.

During the period January 1, 1975 through June 30, 1975, we have indexed

275 papers, reports, etc. dealing directly with LNG safety, and properties

of methane and LNG. Of these, 204 were sent to ASRDI in machine-readable

form on magnetic tapes.

8. Problem Areas . None

9. Funding . January 1 - June 30, 1975

10. Future Plans . We will continue to index safety-related papers and should

complete approximately 250 of these in the next reporting period.

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

Labor 0.5 MY

Other Costs

NASA/ASRDI

26.6 K$

3.3 K$

29.9 K$

8.9 K$

Total

Remaining

4
i. Title. THERMOPHYSICAL PROPERTIES DATA FOR PURE COMPONENTS

OF LNG MIXTURES

Principal Investigators . R. D. Goodwin, G. C. Straty, L. A. Weber,

and H. M. Roder

2. Cost Center Number . 2750574 (2750364)

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

4. 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 thermophysical properties of

mixtures on the composition.

This project will provide comprehensive accurate thermophysical

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.

5. Objectives or Goals . The objectives of our work are the determination

of comprehensive accurate thermophysical 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

.

6. 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 measurements

;

5
compressibility data give the dependence of thermodynamic properties

on pressure and density (at fixed temperatures) ; calorimetric 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 multicomponent 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

.

7 . Program and Results .

7.1 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 pressures 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 measurments on

ethane, relatively high density fluid would reside in external parts of

the system which could not be accurately accounted for in a conventional

apparatus

.

During previous reporting periods, 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. Thermometric sensors were calibrated and installed to these various portions

6
of the apparatus to enable the temperatures to be measured and accurate

PVT data obtained. 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 [1] was obtained. Ethane vapor pressures were also

measured and found to be in agreement with available published data.

During this reporting period, PVT measurements on ethane have been

essentially completed. Data have been obtained along approximately

50 isochores at uniformly spaced temperature intervals from near the

triple point to 320 K at pressures to 350 bar. Data appear to be

consistent with other available data within the combined experimental

error. A manuscript reporting the results of the ethane measurements

is in preparation.

[1]. R. Prydz and R. D. Goodwin, J. of Chemical Thermodynamics 4-, 127 (1972).

7.2 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

345 bar. The sound velocity data have been combined with the previously

measured PVT data to calculate the isentropic and isothermal compressibilities and the specific heat ratio Cp/Cv

. Measurements along the

compressed fluid isotherms at temperatures of 210 K and above were

limited to a minimum density ranging from about 14 mol/i at 210 K to

about 10 mol/l at 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 1_4, 367 (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/£ along several isotherms. Measurements in

the regions of overlap with the ultrasonic data indicate excellent

agreement, and overall agreement with calculated sound velocity data is

satisfactory. The data have been combined with previously measured PVT

data to obtain the isentropic compressibility and specific heat ratio

Cp/Cv

. A manuscript reporting the results of the hypersound velocity

measurements has been prepared and submitted to Cryogenics for publication.

7.3 Ethane, Dielectric Constant Data—L. A. Weber .

Previous dielectric constant data for ethane have been limited to the

saturated liquid near the triple point and to the saturated liquid and

vapor in the region of the critical point. New experimental work has

been completed on the measurement of the dielectric constants of ethane

as a function of temperature and density over a wide range of densities

in the saturated and compressed fluid. The present data include the

saturated liquid in the temperature range 95 - 300 K and seven isotherms

7
at temperatures between 120 and 323 K and at pressures up to 390 bars.

The capacitance measurements were made with a commercial three-terminal

a-c bridge having a resolution of one part in 10^. The capacitor is made

up of a pair of concentric cylinders and has a stability of one part in

10^ . Dielectric constant measurements are being combined with accurate

density data to form the Clausius-Mossotti (CM) function, l/p (e-l)/(e+2)

which for ethane, like other non-polar fluids, is nearly independent of

the temperature and density. This work has been very valuable for

examining the consistency of the available density data for ethane,

including the new equation of state (PVT) data discussed above and the new magnetic densimeter measurements discussed under "Densities of LNG

Mixtures." Data analysis and report preparation are in progress.

7.4 Ethane, Specific Heat Data—H.M. Roder .

Specific heat data (Cv

) are required to accurately define the derivatives

of the equation of state (PVT) , which in turn are used to calculate

other thermodynamic functions such as enthalpy. Measured values of Cv are particularly valuable to cross-check thermodynamic calculations for

the compressed liquid states. We are preparing for a series of Cv and

^SAT measurements on ethane similar to those completed on methane under

this program [1] . Measurements of the heat capacity of the empty

calorimeter will be extended from 300 to 330 K to permit Cv

measurements

of compressed gaseous ethane at temperatures above critical. Since the

critical temperature of ethane (305.3 K) is well above room temperature,

fluid of relatively high density will reside in the filling capillary part

of the system, and will have to be accounted for accurately.

During this reporting period the heat capacity apparatus has been checked

out electrically, and for vacuum, and some heat capacity measurements

have been made on the empty calorimeter. Accuracy and consistency checks

on methane are planned next

.

[1]. B. A. Younglove, J. Research. NBS 78A , 401 (1974).

8. Problem Areas For ethane, the computation of an accurate thermodynamic

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

measurement technique so far has been developed. Heats of vaporization

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

and compressed liquid ethane in certain temperature regions have not

been measured previously and have only recently been completed at this

laboratory. The melting line is known only with low accuracy and attempts

to measure it using existing apparatus continues to be unsuccessful.

The recently completed (PVT) and dielectric constant measurements

together with specific heat measurements now underway will help

overcome some of the deficiencies. Additional attempts to measure

the melting line more accurately are planned.

8
9 . Funding

.

Man-years expended (January to June 1975) 1.0

Equipment and/or Services Purchased 11.5K$

Total Reporting Period Cost 61.9K$

Balance Remaining (June 30, 1975) 10.0K$

10. Plans for Future Work.

year

Objectives and Schedule: quarter

1975

3 4

Report equation of state

(PVT) data for ethane.

Measure, analyze and report

dielectric constant data

for ethane.

Measure, analyze and report

specific heat data for

ethane

.

>

9

i. Title. PROPERTIES OF CRYOGENIC FLUIDS

Principal Investigators . G. C. Straty, D. E. Diller

2. Cost Center Number . 2750141

3. Sponsor . NBS

4. Introduction . Accurate thermophysical properties data and predictive

calculation methods 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

.

5. 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 temperatures. Precise compressibility,

calorimetric and other physical property measurements 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 techniques.

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

.

6. 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 homogeneity

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

11
contains information on the lifetime of the fluctuations (thermal

dif fusivity) . 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 sound 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 dif fusivities 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.

Program and Results . An apparatus has been assembled for laser light

scattering spectroscopy on compressed and liquefied gases (76 - 300 K,

350 bars). The apparatus consists of a high pressure optical cell,

a cryostat for refrigeration with liquid nitrogen, an argon ion laser

and low-level light detection equipment

.

The light scattered from fluctuations in the fluid can be analyzed with

either digital autocorrelation techniques for the examination of the

very narrow lines associated with scattering from temperature fluctuations

(Rayleigh scattering) or with a pressure scanned Fabry Perot interferometer for the measurement of the Doppler frequency shifts associated

with the scattering from propagating density (pressure) fluctuations

(Brillouin scattering)

.

Data on the hypersound velocities in pure methane have been obtained by

Brillouin scattering techniques at low densities (< 14 mol/Z) where the

large sound absorption in methane prohibits more conventional ultrasonic

measurements. Data have been obtained along several isotherms from

210 K to 300 K at densities down to 1 mol/J£. Agreement with previously

measured ultrasonic velocities in the regions of overlapping data is

good. The data have been combined with previously measured PVT data

to obtain the isentropic compressibility and ratio of the specific

heats. A manuscript reporting the results of these measurements has

been prepared and submitted to Cryogenics for publication.

We are currently working on equipment modifications to permit the

determination of the thermal diffusivity, A/pCp, of pure methane. The

most accurate method of doing this is to use photon-counting and digital

autocorrelation techniques to measure the temporal behavior of the

spontaneous temperature fluctuations occurring in the fluid which is

governed by the bulk fluid thermal diffusivity. This is equivalent to

measuring the very narrow Rayleigh line width and requires a resolution

of about one part in lO-^.

12
Preliminary checks of the modified apparatus on a well-characterized

test fluid appear to have been satisfactory. Further testing with

methane is planned

.

8 . Problem Areas : None

.

9. Funding

.

Man-years expended (January to June 1975)

Equipment and/or Services Purchased

Total Reporting Period Cost

Balance Remaining (June 30, 1975)

17.5K$

0.0K$

0.3

4.7K$

10. Future Plans.

year 1975

Objectives and Schedule: 3 4 quarter

Methane

:

Measure, analyze and

report thermal

diffusivity coefficient

data for methane.

13

1. Title. FLUID TRANSPORT PROPERTIES

Principal Investigator . Howard J. M. Hanley

2. Cost Center Number . 2750124

3. Sponsor Project Identification . NBS-Office of Standard Reference Data

4. Introduction . Studies of the transport properties of mixtures have not

received the attention or support that have been given to equivalent

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.

5. Objectives or Goals . The long range or continuing goal of the program

is to perform a systematic study of the theories and experimental

measurements relating to transport properties, specifically the viscosity

and thermal conductivity coefficients, of simple mixtures over a wide

range of experimental conditions. The specific objectives of the

program include: 1) the systematic correlation of the transport

properties of simple binary mixtures and the development of prediction

techniques, 2) development of a mixture theory for the dilute gas region

and the dense gas and liquid regions, 3) extension of the theory and

prediction techniques to multicomponent systems, and 4) suggested

guidelines for future areas of experimental work.

6. Background . A continuing program has successfully expanded the stateof-the-art of transport phenomena for pure fluids. Information for pure

fluids is required as a prerequisite for mixture studies. The theory of

transport phenomena has been developed and applied to produce practical

numerical tables of the viscosity, thermal conductivity and diffusion

coefficients of simple fluids Ar, Kr, Xe, N2, 02, F2, He, He. Recent

work has extended this approach to methane. It is felt that a successful

mixture program will emerge from combining the results for pure fluids

with equation of state studies. The equation of state work is being

carried out by other investigators in this laboratory.

7. Program and Results . Statistical mechanics has been applied to predict

and correlate the dilute and moderately dense thermophysical properties

of carbon dioxide. 1 Carbon dioxide was selected as a typical polyatomic

molecule to study. The self-diffusion coefficients of methane have been

correlated and tabulated. 2 Results for the dilute gas^transport

properties of oxygen and nitrogen have been published. The well-known

critical point anomaly in the thermal conductivity can now be predicted

to within experimental error. ^ Equations to calculate the dense gas and

liquid transport properties of methane are in press.

15
8, Problem Areas. There are no problem areas at this time.

9, Funding. January 1 - June 30, 1975

Allocation

Labor

Other Costs

57.5 K$

0.5 MY

OSRD

28.0 K$

2.7 K$

Total 30.7 K$

10. Future Plans . The transport properties of methane, ethane, and propane

are in preparation for publication. Mixture studies are in progress

but have to coordinated with corresponding work on the equation of state.

Preliminary studies along this line have been initiated.

References

1. J.F. Ely and H.J.M. Hanley, Mol. Phys . (Sep 1975).

2. K.R. Harris, H.J.M. Hanley et al., "The Self-Diffusion of Simple Fluids,"

Australian National Univ. Press., DRU-RR 2 (1974).

3. H.J.M. Hanley and J.F. Ely, J. Chem. Phys. Ref . Data 2, 735 (1973).

4. H.J.M. Hanley, J.V. Sengers and J.F. Ely, Proc. 14th Int. Conf. Thermal

Conductivity (to be published)

.

5. H.J.M. Hanley, W.M. Haynes and R.D. McCarty, Cryogenics (In Press 1975).

16
i. 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).

2. Cost Center Numbers . 2750142; 2750145

3. Sponsors . NBS; NBS (OSRD)

4. Introduction . Accurate thermodynamic properties data and predictive

calculation methods are needed to design and optimize low temperature

processes and equipment. This project provides new experimental

measurements on equilibrium properties and compilations of evaluated

equilibrium properties data which are suitable for direct technological

use or for the evaluation of predictive calculation methods . This

project supports the development of LNG technology in the areas of

separation, purification, liquefaction and custody transfer by defining

relationships between the composition, temperature, pressure, and

equilibrium state properties for mixtures related to LNG.

5. 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,

evaluation 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

deficiencies noted in (a) , (b) , and (c)

.

e) Performing experimental research to alleviate deficiencies

and provide a basis for improvement of prediction methods.

6. Background . A physical equilibria of mixtures research 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) —with one of the quantum

17
gases—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 prediction of deviations from

the geometric mean rule for combining characteristic energy parameters.

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 fundamental 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.

7. Program and Results . The recent progress of this program is summarized

as follows:

a) The comprehensive bibliography of fluid mixtures data entitled

"Equilibrium Properties of Fluid Mixtures: A Bibliography of

Cryogenic Data" was updated to January 1975. A camera-ready

copy was transmitted to Plenum Press during the first part of

April and publication is expected by mid-summer 1975.

b) Work is continuing on the compilation of liquid-vapor equilibrium

data and derivation of the excess Gibbs functions and Henry's

constants for binary systems containing methane with the light

hydrocarbons, argon and nitrogen. A paper, "On the Consistency

of Liquid-Vapor Equilibria data for Binary Mixtures of Methane

with the Light Paraffin Hydrocarbons," which covers a portion of

this work, will be presented at the 1975 Cryogenic Engineering

Conference

.

c) A paper has been submitted to Cryogenics entitled "Liquid-vapor

Phase Equilibria in the System N2 + CH4 from 130.00 K to 180.00 K."

This paper includes an evaluation of available data for this

system, as discussed in (b) , as well as the new measurements.

d) Preparations have also been made to start liquid-vapor equilibrium

composition measurements at selected conditions for the methane

+ ethane system. Measurements are expected to begin during the

next quarter.

8 . Problem Areas . None

.

9 . Funding .

Man-years expended (January 1 - June 30, 1975)

Equipment and/or Services Purchased

Total Reporting Period Cost

Balance Remaining (June 30, 1975)

4.0K$

52.0K$

0.0K$

0.7

18
10. Future Plans.

year

Objectives and Schedule: quarter

1 975

3 4

Compile, evaluate, correlate

and report liquid-vapor

equilibrium data for methaneethane mixtures

.

Measure, analyze and report

liquid-vapor equilibrium

data for methane-ethane

mixtures

.

19

i. Title. DENSITIES OF LIQUEFIED NATURAL GAS MIXTURES

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

2. Cost Center Numbers . 2751574, 2752574

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

Association, Inc., Project BR50-11.

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

require 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 processing

conditions, accurate methods are needed for calculating liquid densities

at arbitrary compositions, temperatures and pressures. 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

mainly 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 independent

professionals of established reputation.

Prior to this reporting period an apparatus incorporating a magnetic

suspension technique has been developed for absolute density measurements

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 gas in the

following temperature ranges: (a) methane (105 - 160 K) ; (b) ethane

21
(100 - 270 K); (c) propane (100 - 280 K) ; (d) normal butane (135 - 300 K)

;

(e) isobutane (115 - 300 K) ; and (f) nitrogen (95 - 120 K) . Measurements

have also been carried out for the following binary mixtures:

(a) 0.49 CH

4

+ 0.51 C 2H6 (105 - 140 K)

;

(b) 0.50 C

2H6 + 0.50 C 3H8 (105 - 140 K)

;

(c) 0.50 CH4 + 0.50 C

3Hg (105 - 130 K)

;

(d) 0.05 N

2 + 0.95 CH4 (105 - 140 K)

;

(e) 0.49 N

2 + 0.51 CH4 (95 -- 130 K)

;

(f) 0.67 C 2H

6

+ 0.33 C

3

H

g (125 - 140 K)

;

(g) 0.92 CH

4

+ 0.08 nC

4

H

1Q

(105 - 140 K)

;

(h) 0.59 C

3

H

g

+0.41 nC

4

H

lQ (110, 135, 140 K) ; and

(i) 0.61 C

3

H

g

+ 0.39 nC

4

H

1Q

(115 - 150 K)

.

The evaluation and optimization of predictive calculation methods for the

densities of LNG mixtures has continued. The corresponding states model

[1] has been tested and optimized using data for selected binary mixtures

(e.g. methane-ethane, methane-propane, ethane-propane, etc.). The

modified hard sphere equation of state model [2] has been tested using

data for selected binary mixtures (e.g. methane-n-butane, propanen-butane, etc.).

References

:

[1] Mollerup, J. and Rowlinson, J. S., Chemical Engineering Science,

29, 1373 (1974).

[2] Rodosevich, J. B. and Miller, R. C, Advances in Cryogenic Engineering , 19, 339 (1974).

8 . Problem Areas . None

9 . Funding

.

2751574 (measurements)

Man years expended (Jan. 1 - June 30, 1975) 0.8

Equipment and/or services purchased 6.1K$

Total reporting period cost 42.3K$

Balance remaining (June 30, 1974) 20.0K$

.22
2752574 (calculation methods)

Man years expended (Jan - Jun 1975)

Equipment and/or services pruchased

Total reporting period cost

Balance remaining (June 30, 1975)

10. Plans for Future Work.

year

Objectives and Schedule: quarter

19 75

3 4

Measure orthobaric densities

of binary mixtures

containing methane, ethane,

propane, butanes and

nitrogen.

Evaluate and optimize

available density

calculation methods.

0.25

3.4K$

10.1K$

32.4K$

23

i. Title. LOW TEMPERATURE MATERIAL BEHAVIOR

Principal Investigators . H. I. McHenry and R. P. Reed

2. Cost Center Number . 2750430

3. Sponsor Project Identification . Maritime Administration Project

55-300-15-011.

4. Introduction . For cryogenic applications, the ASME Boiler and Pressure

Vessel Code and the API Standard 620 Appendix Q Code specify the same design allowable stress level for 5Ni steel as for 9Ni steel. Since

5Ni steel costs approximately 20% less than 9Ni steel, significant cost

savings could be achieved by using this material for LNG applications.

At the present time, 5Ni steel cannot be used in place of 9Ni steel for

marine applications because the U. S. Coast Guard has not approved it.

The principal reasons that the USCG has delayed approval are lack of

service experience in land based tankage and concern that the fracture

resistance of the weld heat affected-zone is inadequate.

5. Obj ectives . This program is being conducted to evaluate the fracture

resistance of the heat affected zone of 5Ni steel weldments at room

temperature, 111 K and 76 K.

6. Background . This program is a continuation of the program conducted by

NBS for MarAd to determine the mechanical properties of candidate material;

for LNG tankage. Their work demonstrated that 5Ni steel plate has

adequate mechanical properties for LNG applications. Further work was recommended to verify that the plate properties would be retained in the

weld heat affected zone.

7. Program and Results . The program to evaluate 5% Ni steel weldments

consists of evaluating the weldment toughness in accordance with the

USCG requirements for weld procedure qualification and determine the

fatigue crack growth and fracture toughness properties of the weldment.

Weld procedure qualification involves testing three Charpy impact speci- mens at five locations within the weld zone: at the weld centerline,

the fusion line, and the heat affect zone at 1, 3 and 5 mm beyond the

fusion line. The fatigue crack growth properties will be determined

for the case of a crack growing through the thickness. Bend specimens

will be used to enable definition of the part of the heat affected zone most susceptible to crack growth. Fracture toughness will be determined

using J-integral procedures.

To date, the weldments have been fabricated by the Armco Steel Company;

and the Charpy impact specimens for task one and the fatigue crack

growth specimens for task two have been machined.

8. Problem Areas. None.

25
9. Funding . January 1 - June 30, 1975

Expended as of June 30, 1975 $ 5,000

Remaining $45,000

10. Future Plans. All testing will be completed in the next six months.

26
1. Title. PROGRAM FOR REDUCING THE COST OF LNG SHIP HULL CONSTRUCTION PHASE II SHIP STEEL IMPROVEMENT PROGRAM

Principal Investigators . H. I. McHenry, M. B. Kasen, and R. P. Reed

2. Cost Center Number . 2753430 - LNG Ship Hull Materials (Shipyard Contracts)

2751430 - LNG Ship Construction Materials (Metallurgical Evaluation)

2752430 - LNG Ship Hull Materials (Fracture Properties)

3. Sponsor Project Identification . Maritime Administration Project

400-58073.

4. 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 properties but extreme care must

be exercised during welding to avoid degradation of the steel adjacent

to weld (the heat affected zone) to a level of toughness below U. S. Coast Guard requirements. 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. The feasibility of reducing the cost of LNG ship hull construction was investigated in Phase I of this project, leading to the Phase II program described below.

5. Obj ective . The obje<_cives of the Phase II program are 1) to have the

four major plate producers supply the four LNG shipyards with production

heats of ABS steels modified to possess improved transverse fracture

properties at low temperatures, 2) to have the LNG shipyards evaluate

these plates by qualifying optimum welding procedures in accordance with

the USCG requirements, and 3) to provide a metallurgical evluation of

factors that influence heat affected zone toughness in the improved

steels

6. Background . Early in 1974, the Welding Panel of MarAd f 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 1974. In mid-October, MarAd approved the initial phase of

NBS's recommended program, i.e., to survey the problem and the technology available for its solution. On the basis of this survey and as the result of a meeting of the Welding Panel in March, 1975, a coordinated program involving the LNG shipyards, the steel suppliers, and NBS

was recommended to MarAd and to the Welding Panel. This program was approved and work started in May 1975.

£American Bureau of Shipping.

27
7. Program and Results . The Ship Steel Improvement Program consists of

three primary tasks:

Material Acquisition

Shipyard Evaluation

Metallurgical Evaluation

Currently, the program is in the material acquisition phase. The steel

procurement plans are summarized below:

Shipyard Steel Company Test Temperature Steel Grade*

Avondale Armco -25°F V-051

Avondale Armco -50°F V-051 (SCC)**

Newport News Bethlehem -25°F V-051 (SCC)

Newport News Bethlehem -50°F V-051 (SCC)

General Dynamics /Quincy U.S. Steel -25°F CS (SCC)

General Dynamics /Quincy Bethlehem -60°F EH (SCC)

Sun Ship Luhens -40°F EH (Cb)***

Sun Ship Luhens -60°F EH (Cb,SCC)

*The steel grades V-051, SC and EH are American Bureau of Shipping

(ABS) steels.

**SCC - Sulfide Shape Control

***Cb - Columbium Treated

Procurement is contingent upon completion of the contractual arrangements between the shipyards and NBS.

Upon receipt of material, each participating shipyard will evaluate the

steel plates by qualifying optimum weld procedures in accordance with

USCG requirements. The welding processes being qualified are submerged

arc, gas metal arc, and shielded metal arc. The test weldments will

also be subjected to a metallurgical evaluation to determine the effect

of microalloying and sulfide shape control on heat affected zone tough- ness .

8. Problem Areas . Contract negotiations with each of the shipyards have

not yet been completed. Thus, the steel procurement has been delayed.

9. Funding . Cost Center Cost to 6/30/75 Balance

2753430 $40 K $150 K (obligated)

2751430 $40 K* $ 35 K

2752430 $ 5 K $ 35 K

*Includes phase I costs.

10. Future Plans . Steel procurement should be completed and the shipyard

and metallurgical evaluations should be started during the next reporting period.

28
1. Title. CUSTODY TRANSFER - LNG SHIPS

Principal Investigators . R. S. Collier and P. J. Giarratano

2. Cost Center Number . 2750460

3. Sponsor Project Identification . Maritime Administration, Project

55-330-15-011.

4. Introduction . In response to a request from the U.S. shipbuilding

industry, NBS is conducting an independent design review of the shipboard custody transfer systems under the sponsorship of the Maritime

Administration and in cooperation with the major U.S. shipbuilding

companies

.

5. Obj ectives . The objectives of this program are to 1) Identify the

major technical areas relating to uncertainties in the measurement of

total mass and total heating value, 2) Estimate uncertainties in the

total mass and total heating value due to these identified factors,

3) Develop a proposed testing program for custody transfer system com- ponents, and 4) Investigate improved gauging techniques.

6. Background . Calendar year 1974 funding provided for the initial re- view of ships designated by MA Design LG8-S-102a MA Hulls 289, 290, 291.

The current funding provides for an extension of this program to include

ships of other designs which are being built by the major U.S. shipbuilding companies

.

7. Program and Results . Working relations between three of the four major

U.S. shipbuilders have been established. Most of the problem areas which are common to custody transfer systems of all types have been

identified and are listed as follows:

1. Density

a) accuracy

b) rangeability

c) stability

2. Tank Strapping

a) thermal effects

b) loading factors

c) measurement techniques

3. Convection (Non-Uniform Density)

a) density or composition stratification

b) possible isolation of measurement stillwells

4. Tank Weathering

a) time changes in composition, stratification, etc.

b) composition measurement

c) sampling

29
5o

6,

Liquid Level/Total Volume Measurement

Pressure and Temperature Measurements (gradients included)

.

7, Electronic Signal Conditioning, Data Reduction, Analysis and

Readout.

In addition, further progress was made in calculating uncertainties in

density measurement, variations in composition due to tank weathering

and thermal effects associated with hydrostatic head pressure within

the tank.

8. Problem areas . One of the most difficult estimates to make is the

degree of density or composition stratification within the tank; this

could also include the effect of stillwells and remote access areas within the tank. It will probably not be possible to estimate these

effects to the desired accuracy. It is therefore recommended that some of these ship tanks be fitted experimentally to measure density,

temperature and composition at various locations within the tank during

the normal course of checkout of these systems.

9. Funding . January 1 - July 1, 1975

10. Future Plans .

1. Conduct a complete rangeability test of the capacitance type

densitometer.

2. Continue a program of exchange of information with the U.S. shipbuilding companies.

3. Recommend procedures and facilities for testing a 15 meter

capacitance type liquid level vernier.

4. Conduct further experiments on RF gauging in large tanks.

Man-Years this Period

Total Cost

Balance (July 1, 1975)

0.5

$29,887

$45,113

30
i. 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 objective of this program is to measure the heating

value of LNG flowing in a pipeline by the integration of individual

measurements of flow, density and heating value. Flow measurement re- quires determination of flowmeter performance in line sizes larger than

presently available calibration facilities. Therefore, a secondary

objective is to establish appropriate flowmeter scaling laws.

6. Background . The LNG flow facility at NBS will be utilized to evaluate

the response of the individual elements in the heating value measurement. Different compositions of LNG will be prepared to provide a range

of densities sufficient to determine any dependencies. A limited amount

of sampling work is included to determine the relative importance of

this parameter to the overall measurement.

Flowmeter scaling is being done utilizing the cryogenic and the water

flow facilities at NBS and private LNG peak shaving facilities. This

portion of the program is behind schedule because of scheduling problems at the private LNG facilities.

7. Results . LNG tests on the four-inch flowmeter that had been scheduled

at an industrial LNG plant for early 1975 were not completed because

there was no LNG send out. It now appears that a brief test might be

possible during late November or early December 1975. Therefore, this

critically important phase of the program has been delayed approximately

one year from the original plan. In order to keep the delay in the

flowmetering phase of the program as short as possible it was decided

to go ahead with the necessary plans for the next larger size flowmeter

(eight inch) and try to test both sizes during the next send-out season. An alternate industrial LNG plant was also selected which has a higher

probability of sending out LNG during the next send-out season. This

change in sites might also provide test data on the four inch meter that

31
would not have been available before. To get this additional data, the

four-inch meter will be left installed in the original facility until

after the tests in November or December. The flowmeter will then be

moved to the alternate site for additional testing in conjunction with

tests on the eight inch flowmeter.

Tests on the NBS flow facility are now scheduled for the summer months.

This schedule was necessitated when an adequate supply of LNG was not

available and it was necessary to assemble a natural gas condenser. A

minimum amount of interference with the flowmeter field tests will

result by conducting these tests during the summer months.

8. Problem Areas . Major problem areas encountered have been in scheduling

tests as described above. Locating a suitable supply of LNG resulted

in some delay but the resulting solution should provide more flexibility

in later stages of the program.

9. Funding .

10. Future Tests . The flowmeter tests at an LNG peak shaving plant have

been rescheduled for November or December 1975 (4-inch) and January or February 1976 (4- and 8-inch) . Tests on the NBS integrated flow facility are scheduled to start during July 1975.

Man-Years Expended

Major Equipment Purchased

Total Reporting Period Costs

Balance on Hand (to Dec. 31, 1975)

$10,000

$55,000

$70,511

1.0

32
1. Title. LNG DENSITY REFERENCES 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 determinations 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.

6. Background . The density reference system was initiated in 1973 with a proposal to the AGA for research on LNG technology. Since that time

the reference system has been selected, designed, constructed, and is

now in operation, evaluating density metering systems.

7. Program and Results . The density reference system has shown consistent

good agreement in density measurements to the densities of Haynes (ref

.

cost center 2751574) for liquid methane. That is, essentially all of

the measurements are within 0.15% of Haynes.

Data on the performance of density measurement by the vibrating cylinder,

vibrating plate, and capacitance meter in liquid methane have been taken.

The suppliers of the above densitometers have kept in close touch with

the progress in evaluation of their meters. There has been some malfunctioning in these devices and some modifications made (see item #8

below) . The capacitance meter was altered by its design engineer to

include a temperature sensor (platinum thermometer) and a new set of

electronics for readout. This device now features readouts of density,

temperature, and capacitance. The designer's intent is that the temperature sensor will allow a more accurate measurement of density over variations in hydrocarbon composition.

33
We have had input from the NBS statistical group as to statistical

approaches for testing, they have also been of significant help in

advising on detailed operation of the weighing head.

Colin McClune of Thornton Research Center (Shell Research Ltd.) has

visited us and has given us the benefit of his knowledge on the qualitative behavior of two of the above devices. He intends to make further

evaluations with his density system. It is our intention to keep in

touch with his progress.

8. Problem Areas . The weighing head continues to be a challenge regarding

reliability. Its electronic control circuit completely failed and was replaced by an improved circuit. The unweighing device has given some problems, but now the weighing head system appears to perform properly.

The vibrating cylinder device was returned for repair of a pressure

leak (at cold temperatures).

The vibrating plate device has, on occasion, shown mode-locking errors. However the designer of this device has stated that this can be avoided

by making an adjustment in the phase delay circuit. We intend to have

him make this adjustment.

9. Funding . January 1 - June 30, 1975

10. Future Plans . First three months. Complete measurements of the installed densitometers on methane and its mixtures with the heavier

hydrocarbons. Analyze data accumulated. Install magnetic buoy system

and commence evaluation.

Second three months. Complete density meter evaluation. Write summary

of test results on all meters.

Principal Investigators 0.72 man years

Technician 0.12 man years

Equipment

Other

$37,700

4,500

5,400

1,600

TOTAL

Balance as of June 30, 1975

$49,200

$ 1,600

"34
1. Title . LIQUEFIED NATURAL GAS TECHNOLOGY TRANSFER

Principal Investigator . D. B. Mann

2. Cost Center Number . 2750401

3. Sponsor Project Identification . Maritime Administration, Project

01 220 03 211, Purchase Order Number 400-58074.

4. Introduction . The NBS support of the Maritime Administration (MarAd)

LNG ship program is divided into three areas. These are a materials

experimental program, LNG ship custody transfer, 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. Obj ectives . 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. Recent proposals to liquefy and transport Alaskan

gas to the U.S. only reinforced the importance of this new technology

to providing a measure of energy self-sufficiency to the U.S.

LNG marine technology is presently foreign dominated. As a matter of

fact, many of the ships being constructed in U. S. shipyards 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 industrial 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 some 20 years, the NBS

Cryogenics Division was requested to provide support to the MarAd LNG

ships program in order to aid in the transfer of cryogenic technology

where it could enhance the effectiveness of maritime LNG shipping.

Therefore, on April 17, 1973 we submitted a work statement which was confirmed by the establishment of a program in May of that year.

•35
7. Program and Results . In the initial phases of the LNG Cryogenic Technology Transfer Program emphasis was placed on establishing the level

and degree to which we could interface with MarAd and MarAd .contractors.

Progress, therefore, is measured as specific responses to MarAd and

MarAd contractor requests and NBS generated output felt necessary for

the overall program. The materials experimental program is described

under Cost Center 2750430. The problems associated with custody transfer of LNG ships is described under Cost Center 2750460 and the positive

dissemination of information from these and other NBS programs is performed under this cost center. In addition, information developed

under a program for reducing the cost of LNG ship hull construction is

described under Cost Centers 27501430, 27502430, and 2753430.

A program for the standarization, dissemination, and utilization of LNG

related property data has been formulated. It has the following three

obj ectives

:

1) To secure review, approval, and acceptance of the mechanical,

thermophysical, and thermodynamic property data of interest to the LNG

industry by the gas industry and voluntary and statuatory standards

agencies.

2) To define and make available these data in a form most useful to

the ultimate user.

3) To define the most economical and effective method of distributing

this data to the ultimate user. Support for this proposed program has been solicited from the sponsor

(MarAd) , the Pipeline Research Committee (AGA) LNG Supervisory Committee,

the AGA Operating Section LNG Committee, the Research and Engineering

Division of the American Gas Association and the National Gas Producer

Suppliers Association. Assessment of the response to these presentations

is in progress.

8. Problem Areas . The effective dissemination of information on cryogenic

technology is basic to the overall ovj ectives of this Cost Center. The

main road block to achieving the objectives is definition by the user

of the form in which the information should be available. Solution of

this problem involves continued interaction between the Cryogenics

Division and the ultimate user with the possible generation of a prototype of one or more methods for circulation, comments, and criticism.

9. Funding . January 1 - June 30, 1975.

Labor 0.2 man years

Cost $10,000

10. Future Plans . Funding for this program extends to the end of calendar

year 1975. During this period several prototype methods of data dissemination will be attempted. These would include a data book, simplified computer programs, and the outlining of symposia or conferences to

achieve the maximum awareness of information generated under this program.

36
1. Title . ENERGY CONSERVATION POTENTIAL IN THE LNG INDUSTRY

Principal Investigators . D. B. Mann and T. M. Flynn

2. Cost Center Number . 2750103

3. Sponsor Project Identification . NBS Office of Energy Conservation

4. Introduction . By the end of 1975, there will be 166 LNG projects around

the world in operation, under construction, planned, or proposed.

Peak shaving accounts for the largest number of LNG facilities with 106

being completed within the U.S. This number includes 55 actual peak

shaving plants (which include liquefaction, storage, and gasification

equipment) and 51 satellite facilities (which consist of storage and

gasification equipment, but no liquef ier) . These 106 plants comprise

a total storage capacity of approximate!}7 65 billion cubic feet (equivalent gas volume) and a total liquefaction capacity of approximately

295 million cubic feet per day.

The impact of energy shortages world wide has underscored the need to

utilize this resource (LNG) as efficiently as possible. Therefore,

this program has been undertaken to provide the measurements and data

base necessary for energy conservation in the Liquefied Natural Gas (LNG)

industry. It will identify sources and degree of thermodynamic losses

incurred during liquefaction, shipping, storage, and regasif ication of

LNG and assure an adequate cryogenic measurement methodology and data

base to facilitate the most effective use of Liquiefied Natural Gas.

5. Obj ectives . The objective of the project is to provide the technical

basis for the planned management of the cryogenic aspects of liquefied

natural gas to enable its more effective utilization and prevent its

exploitation or neglect. It will include, for instance, thermodynamic

analyses of representative LNG systems to define the thermodynamically

"ideal" base for comparison to actual practice. It will identify and

test instruments and measurement techniques in support of energy con- servation, and analyze and test the feasibility of energy recovery

through utilization of the cold in LNG.

6. Background . New project.

7. Program and Results . During this fiscal year, we completed the first

four months of an intended three year study whose ultimate purpose is

to provide the measurements and data base necessary for energy conser- vation in the Liquefied Natural Gas (LNG) industry. Progress made

during these first four months include:

1) An historical perspective of the LNG industry;

2) The selection of peak shaving as the first subject for study,

including a description of the process and essential components;

3) A thermodynamic analysis of peak shaving process;

4) and an identification of the most pressing measurement and instrumentation needs.

37
Specific objectives during this first period were to provide:

1) A documentation and definition of the LNG industry.

2) An LNG peak shaving process description.

3) A description of the variations among LNG peak shaving process

components.

4) Thermodynamic analysis — reversible process.

5) Thermodynamic analysis — limitations.

6) Thermodynamic analysis — applications to existing facilities.

7) An analysis of energy conservation through the potential of

refrigeration recovery, or cold utilization.

8) An identification of tentative measurement instrument needs.

9) A base for measurement development for conservation requirements.

Among our first conclusions are the following:

1) LNG peak shaving is an established and growing U.S. industry.

2) Adequate technical information is available for conservation

analysis.

3) The peak shaving process is subject to analysis using classical

thermodynamics

.

4) It is possible to establish a thermodynamically reversible process as an ideal.

5) Some irreversibilities are dictated by external requirements of

the process.

6) Liquefaction is the largest single irreversibility, followed by

storage losses.

7) Process efficiencies could be further enhanced if it were possible

to build an integrated plant where cold utilization were a coor- dinated objective.

8) Tentative measurement requirements identified are: therm-meter,

densitometer, flowmeter, liquid level and mixture fraction, all

in gas or cryogenic liquid phases.

9) Thermodynamic, electrodynamic, transport, and phase quilibrium

properties data are inadequate as of the reporting period. Existing experimental and analytical programs on property data will

eliminate this inadequacy, within the scope of the three year study.

8 . Problem Areas . None

9. Funding . $40 K, NBS Office of Energy Conservation, Division 460.04.

10. Future Plans . Plans for the remainder of the study include the following elements:

1) Complete peak having plant efficiency analysis. Expected outputs

would include:

a. Complete ranking of major loss components.

b. Quantify losses in terms of energy.

c. Identify measurements, instrumentation, and process improvement opportunities.

d. Quantify energy-benefit for each measurement, instrument, or process improvement.

38
Implementation

a. Field testing of existing instruments in conjunction with

energy conservation demonstration projects.

b. Selection and analysis of new measurements and instruments.

c. Field testing of new measurement devices and techniques in

conjunction with demonstration projects.

Promote LNG Energy Conservation Program.

a. Identify and document net energy to be saved.

b. Identify and document additions to net energy supplies.

39

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 systems, 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 presently under the jurisdiction of the Federal Power Commission and subject to our review are outlined in the following table.

Elements of the facilities that are subject to review are the landbased 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 technical 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 . Funding FY 76 $50,000

January 1 - June 30, 1975 22,000

Anticipated Man Years of Effort FY 76 0.8

8. Future Plans . At the present time there are several pending applications,

but detailed information is not yet available. It is anticipated that

additional facilities will be reviewed as applications are made to the

Federal Power Commission.

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42
I14A (REV. 7-73)

U.S. DEPT. OF COMM.

IBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO.

NBSIR 75-817

2. Gov't Accession

No.

3. Recipient's Accession No.

TLE AND SUBTITLE

LIQUEFIED NATURAL GAS RESEARCH AT THE NATIONAL BUREAU

OF STANDARDS

5. Publication Date

6. Performing Organization Code

275.00

UTHORlS)

D. B. Mann, Editor

8. Performing Organ. Report No.

ERFORMING 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.

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

Same as Item 9.

13. Type of Report & Period Covered

Semi-Annual - January

inrougn June ±y/j

14. Sponsoring Agency Code

SUPPLEMENTARY NOTES

ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.)

Nineteen cost centers supported by six other agency sponsors in addition to NBS

ovide the basis for liquefied natural gas (LNG) research at NBS. During this six

i nth reporting period the level of effort was at an 18 man-year level with funding

i penditures of over $500,000. This integrated progress report to be issued in

. nuary 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

onsors, but will not necessarily replace such meetings. Distribution of this document

limited and intended primarily for the supporting agencies. Data or other infortion must be considered preliminary, subject to change and unpublished; and therefore

t for citation in the open literature .

I 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.

AVAILABILITY Unlimited

i X For Official Distribution. Do Not Release to NTIS

1

' Order From Sup. of Doc, U.S. Government Printing Office Washington, D.C. 20402, SD Cat. No. CI 3

1

1 Order From National Technical Information Service (NTIS)

Springfield, Virginia 22151

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

21. NO. OF PAGES

20. SECURITY CLASS

/

(THIS PAGE)

UNCLASSIFIED

22. Price

USCOMM-DC 29C4 2-P74