NBSIR 79-1603

LIQUEFIED NATURAL GAS RESEARCH

at the

NATIONAL BUREAU OF STANDARDS

PROGRESS REPORT FOR THE PERIOD

1 July - 31 December 1978

MEASUREMENT

SCIENCE

REFERENCE

DATA

LNG

TECHNOLOGY

TECHNOLOGY

TRANSFER

THERMOPHYSICAL PROPERTIES DIVISION. NATIONAL ENGINEERING LABORATORY.

NATIONAL BUREAU OF STANDARDS. BOULDER. COLORADO

NBSIR 79-1603

LIQUEFIED NATURAL GAS RESEARCH

at the

NATIONAL BUREAU OF STANDARDS

Thermophysical Properties Division

National Engineering Laboratory

National Bureau of Standards

Boulder, Colorado 80303

Progress Report for the Period

1 July - 31 December 1978

U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Sidney Harman, Under Secretary

Jordan J. Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
Prepared for:

American Gas Association, Inc.

1515 Wilson Boulevard

Arlington, Virginia 22209

LNG Density Project Steering Committee

(in cooperation with the American Gas Association, Inc.)

Pipeline Research Committee

(American Gas Association, Inc.)

Gas Research Institute

10 West 35th Street

Chicago, Illinois 60616

U. S. Department of Commerce

Maritime Administration

Washington, DC 20235

U. S. Department of Commerce

National Bureau of Standards

National Engineering Laboratory

Boulder, Colorado 80303

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 International Standards

Washington, DC 20234

LNG Custody Transfer Measurements Supervisory Committee

National Aeronautics and Space Administration

Lewis Research Center

Cleveland, Ohio 44135
ABSTRACT

The objective of this report is to:

1. provide all sponsoring agencies with a semiannual report on the

activities of their individual programs;

2. inform all sponsoring agencies on related research being conducted

at the Themophys ica 1 Properties Division;

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 work is supported by NBS and seven other agencies and represents the

collective expenditure of $400,000 during the 6-month reporting period. The

contents of this report augment quarterly progress meetings for certain of our sponsors and provide a perspective which is missing when the parts are viewed individually. 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 . During this reporting period we have issued the first supplement to the

" LNG Material and Fluids" Users Manual.

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

properties; research.
CONTENTS

Cost Center Page

I

.

REFERENCE DATA

a) THERMOPHYSICAL PROPERTIES DATA FOR PURE

COMPONENTS AND MIXTURES OF LNG COMPONENTS

(Gas Research Institute; American Gas

Association, Inc.; NASA Lewis Research

Center)

7360574,

7360548

1

b) FLUID TRANSPORT PROPERTIES

(NBS-Of f ice of Standard Reference Data)

7362290 5

c ) PROPERTIES OF CRYOGENIC FLUIDS ( NBS

)

7360122

7360124

7360125

7

d) PROPERTIES OF CRYOGENIC FLUID MIXTURES

(NBS; NBS-Office of Standard Reference

Data; GRI)

7360123,

7362289,

7368574

11

e) DENSITIES OF LIQUEFIED NATURAL GAS MIXTURES

(LNG Density Project Steering Committee - AGA)

7361574 13

f

)

PROGRAM FOR REDUCING THE COST OF LNG SHIP

HULL CONSTRUCTION — PHASE II SHIP STEEL

IMPROVEMENT PROGRAM (Maritime

Administration)

7363430 , 7361430,

7362430

15

II

.

MEASUREMENT SCIENCE

a ) CUSTODY TRANSFER - LNG SHIPS (Maritime

Administration; LNG Custody Transfer

Measurements Supervisory committee

7360460,

7361575,

7362575,

7363575,

7311573,

7311577

17

b) HEATING VALUE OF FLOWING LNG (Pipeline

Research Committee - AGA)

7362570 19

c ) LNG DENSITY REFERENCE SYSTEM (American Gas

Association, Inc.; Gas Research Institute

7367574 20

d ) LNG SAMPLING MEASUREMENT STUDY (Pipeline

Research Committee - AGA)

7363570 22

Ill

.

TECHNOLOGY TRANSFER

a) SURVEY OF CURRENT LITERATURE ON LNG AND

METHANE (American Gas Association, Inc.;

Gas Research Literature)

7369574 24

IV
CONTENTS (continued)

b) LIQUEFIED NATURAL GAS TECHNOLOGY TRANSFER

(Maritime Administration; American Gas

Association, Inc.; Gas Research Institute;

NBS-Office of Standard Reference Data)

c) OIML JOINT SECRETARIAT ON LNG MEASUREMENTS

(American Gas Association, Inc.; NBSOffice of International Standards;

NBS-Thermophys ical Properties Division)

Page

7360403, 27

7361403,

7364574 , 7368574,

7362287,

7360461,

7360594

7360290 29

v

1 . Title . THERMOPHYSICAL PROPERTIES DATA FOR PURE COMPONENTS AND MIXTURES

OF LNG COMPONENTS

Principal Investigators . R. D. Goodwin, H. M. Roder, G. C. Straty,

W. M. Haynes, R. D. McCarty, D. E. Oilier, and B. A. Younglove

2 . Cost Center Numbers . 7360574, 7360548

3. Sponsor Project Identification . Gas Research Institute Grant No.

5010-362-0019 and American Gas Association, Inc., Project BR-50-10.

National Aeronautics and Space Administration, Lewis Research Center,

Purchase Order C-78014-C.

4. Introduction . Accurate phase equilibrium, equation of state (PVT), and

thermodynamic properties data are needed to design and optimize gas

separation and liquefaction processes and equipment, and for mass and

heat transfer calculations. Accurate data for the pure components and

selected mixtures of hydrocarbon systems will permit developing

comprehensive accurate predictive calculation methods which take into

account the dependence of the thermophysical properties of mixtures on the composition, temperature, and density.

This project will provide comprehensive accurate thermophysical

properties data and predictive calculation methods for compressed and

liquefied hydrocarbon gases and their mixtures to support the

development of LNG technology at NBS and throughout the fuel gas

industry. It will also serve as the base for a comprehensive mixtures

prediction methodology.

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) and selected mixtures of liquefied

natural gas and hydrocarbon mixtures at temperatures between 80 K and

320 K and at pressures up to 35 MPa (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 1978 - 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 and hydrocarbon 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 mixture data prediction

methods are needed for use in automated heat transfer calculations.

Accurate thermodynamic properties data for liquefied gas mixtures must

be based on precise compressibility and calorimetric measurements;

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 must usually be predicted

1
(extrapolated) from a limited number of measurements on the pure

components and their binary mixtures. This project was initiated to

provide the natural gas and aerospace industries 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), and National Bureau of Standards Technical Note 684, "Thermophys- I ical Properties of Ethane, From 90 to 600 K at Pressures to 700 Bar," by

Robert D. Goodwin, H. M. Roder, and G. C. Straty (August 1976). These

reports contain the most comprehensive and accurate tables available for

the thermophysical properties of pure gaseous and liquid methane and

ethane, and provide an accurate basis for calculating thermophysical

properties data for LNG and other hydrocarbon mixtures.

7 . Program and Results .

7.1 Propane, PVTx and Dielectric Constant Measurements -- W. M. Haynes j The experimental measurements of the densities of liquid mixtures of LNG

components have been completed. The LNG density project used the same apparatus that is now being employed for PVT and dielectric constant

measurements on propane. A summary of the LNG density project is given

in the report for cost center 7361574.

After testing the dead weight gauge measurement system, PVT measurements

have been carried out for liquid propane at pressures to 360 bars along

three isotherms at 146, 160, and 178 K (approximately 14 data points per . isotherm) . These data have been compared with the calculated values

from the equation of state for propane developed by R. D. Goodwin. The 1 maximum difference between the calculated and experimental densities was | 0.07% while the average deviation was 0.02%. No problems were encountered in using the apparatus at high pressures.

This apparatus utilizes a magnetic suspension densimeter, which is based

on an application of Archimedes' principle. The uncertainty in the

measured density depends directly upon the uncertainty in the

determination of the volume of the magnetic float. The volume of the

float changes with pressure. Thus measurements have been carried out by

H. M. Ledbetter of our division to determine the bulk modulus of the

float material (barium ferrite) as a function of temperature between 76

and 300 K. These measurements demonstrated that the change in the

volume of the float is less than 0.03% for a pressure change of

360 bars. (The bulk modulus (or compressibility coefficient) of barium

ferrite changes approximately 2% from 76 to 300 K. This corresponds to

a volume change of less than 0.001% for a pressure of 500 bars. For all

practical purposes it can be assumed that the bulk modulus of barium

ferrite is independent of temperature over the temperature range of the

propane measurements.)

One of the coaxial leads to the capacitor used in the dielectric

constant measurements broke when an effort was being made to remove a short to ground from the capacitor cylinder to which this coaxial cable was connected. The apparatus must be disassembled and the coaxial cable

replaced

7.2 Calculational Methods — R. D. McCarty

Work is continuing, at a partial staff-year level, on the extension and

optimization of the corresponding states method to mixtures of methane

with nitrogen and other fluids. The transformation of the methane

surface to N 2 , C>2' Ar > H 2 anc^ C 2 H 4 ^ as been accomplished and

the development work on the transformation function itself has begun. | 2
We have determined that the transformation function previously used for

liquid density near saturation is inadequate for a broader range of

pressure and temperature. Initial efforts in finding a new function are encouraging.

7.3

Propane, Specific Heat Data -- R. D. Goodwin

This project is complete and the results published in "Specific Heats of

Saturated and Compressed Liquid Propane," by R. D. Goodwin, J. Res. Nat.

Bur. Stand. (U.S.) 83, 449-58 (Sep-Oct 1978).

7.4 Butane, Preliminary Thermophysical Properties Data -- R. D. Goodwin

The objective is to prepare provisional tables of thermodynamic

properties of normal and isobutane, using available physical properties

data. In this work we expect to discover those areas of properties data

most in need of further experimental measurements.

In general, there is an abundance of quite inconsistent data from

different laboratories, requiring tedious weightings, selections, and

eliminations. There are few data for liquid butanes at LNG

temperatures

Satisfactory formulations have been developed for the virial equation,

the saturated liquid densities, specific heats for the saturated liquid

below the boiling point, and for the ideal gas thermodynamic functions

for both fluids.

By thermal loops, in a procedure first developed by W. T. Ziegler, we have derived new "data" (where none existed) from the triple- to the

boiling-point for vapor pressures, densities of the saturated vapor, and

for heats of vaporization. The vapor-pressure equation has been

adjusted to include these new data, and a provisional description has

been developed for the heats of vaporization up to the critical point.

Manuscripts for reports on the equation of state and provisional tables

of thermodynamic properties for both n-butane and i-butane are complete

and in the final stages of the NBS review process. They will be

published as NBS Interagency reports.

The work on isobutane was done sooner than planned because of a Department of Energy funded experimental project on that fluid which

will be used as a geothermal working fluid. The latter work is being

done at NBS-Gaithersburg and the two projects will be done on a collaborative basis so that the resulting 'final' tables will serve both

projects. The need for measurements to be made on i-butane at Boulder

will be, consequently, reduced greatly.

7.5 Pure Nitrogen and Nitrogen-Methane PVTx Property Measurements —

G. C. Straty and D. E. Diller

Gas expansion PVT measurements on pure compressed and liquefied nitrogen

have been completed. About 300 measurements were made at 21 densities

in the range 11.2 - 28.4 mol/L, 80 - 270 K, 1 - 350 bars. These

measurements were made to provide more accurate pure component data for an accurate mathematical model of the PVT properties of nitrogen-methane

mixtures

Twelve isochoric gas-expansion PVT runs have been made on a gravimetrically prepared 50.115 mole % nitrogen-49.885 mole % methane mixture in

the T, P, p range 82 - 320 K, 2 - 350 bar, 11 - 28.6 mol/L. The

measurements are being compared with the extended corresponding states

model (R. D. McCarty, NBSIR 77-867 (Oct 1977), which was previously

3
optimized to saturated liquid density measurements on this mixture at

temperatures below 140 K. Differences between calculated and measured

densities range from several tenths percent at low temperatures and high

densities to several percent near the critical temperature (~ 161 K) and

critical density (~ 10.5 mol/L) . About eight more measurement runs are planned.

7.6 Sound Velocity of Propane — B. A. Younglove

New measurements of the sound velocity of propane have been initiated.

We will evaluate the performance of the sound velocity approach in

liquid propane at 100 K to see if the previous geometry is satisfactory.

Drawings were made for a new configuration of spacer length twice the

old length in case the former arrangement does not work. Calculations

for dispersion from correlations available in the literature indicate

that this should not be a problem. This and other features of the

proposed measurements were recently discussed during a visit by Bruce

Gammon of DoE , Bartlesville, Oklahoma, an expert in the field of sound

velocity measurements. We have installed and tested a new vacuum jacket

for the sound velocity cryostat which allows much more convenient

dismantling of the system. The computer programming necessary for

experimental sound velocity measurement has commenced. We have a computer file for computation of propane density from measured values of

temperature and pressure, and a file for computation of sound velocity

from a measurement of frequency using the information obtained from the

previously mentioned calculation. The latter file is not in complete

form. We will next work on checking the system as mentioned above for

general behavior in liquid propane. Also we will check the sample

holder system for temperature gradients, temperature measurement

accuracy and other features required for proper measurement of sound

velocity

.

8. Problem Areas . None.

9. Level of Effort . July 1 - December 31, 1978.

Staff-years expended

Equipment and/or Services Purchased

Approximate expenditures, total

10. Future Plans.

1.1

11 . 2K$

9 6 . 4K$

Objectives and Schedule: Quarter 1 2 Evaluate and optimize promising

calculation methods for the

thermodynamic properties of

methane-nitrogen mixtures.

Measure, analyze and report PVT and

dielectric constant data for propane.

Publish provisional tables of thermodynamic properties for the butanes

and develop an accurate equation of

state

.

Measure, analyze and report sound

velocity data for propane.

4
Title . FLUID transport properties

Principal Investigator . Howard J. M . HanleyCost Center Number. 7362290

Sponsor Project Identification . NBS-Office of Standard Reference Data

Introduction . Methods for predicting the transport properties of fluid

mixtures are unreliable and data are scarce. Prediction methods are needed, however, to supply the necessary design data needed to increase

efficiency and reduce costs.

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.

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

( 3 ) coefficients of simple fluids: Ar, Kr, Xe , N^, 0 F

2

, He, H^, CH^,

r h {4)c h

(5)

C 2b ' C

3 H

8

*

It has been shown that a successful mixture program can emerge from

combining the results for pure fluids with mixture equation of state

studies. The equation of state work is being carried out by other

investigators in this laboratory.

Program and Results . We continue to develop the prediction procedure

for the transport properties of mixtures reported previously. ' We have recently studied the fundamentals via computer simulation^ ' to

assess the scientific justification of the corresponding states

approach

The critical point behavior remains of interest^) and preliminary

results are in process of publication.

The transport properties of pure ethylene are being correlated.

Problem Areas . The lack of suitable experimental mixture transport

properties data for comparison purposes is the main problem. Also

equation of state (PVT) data for mixtures are needed.

Level of Effort . July 1 - December 31, 1978.

Staff-years expended

Equipment and/or Services Purchased

Approximate expenditures, total

0.4

2. 5K$

3 6 . 7K$
10 . Future Plans . The corresponding states predictive procedure for

mixtures will be more fully developed and expanded in line with the

concurrent equation of state studies. We intend to investigate, in

particular, the behavior of the transport properties at gas/liquid and

liquid/liquid equilibria. Computer simulation studies will be expanded

Mixtures in which the components are very different (shape, size, mass,

etc.) will be emphasized.

References

1. H. J. M. Hanley, Prediction of the Viscosity and Thermal Conductivity

Coefficients of Mixtures, Cryogenics, Vol 16, No. 11, 643-51 (Nov 1976)

H. J. M. Hanley, Prediction of the Thermal Conductivity of Fluid

Mixtures, Proceedings 7th ASME Conf . on Thermophysical Properties;

H. J. M. Hanley in "Phase Equilibria and Fluid Properties in the

Chemical Industry," ACS Symp. Series No. 60 (1977).

2. H. J. M. Hanley, Transport Coefficients in the One-Fluid Approximation:

Behavior in the Critical Region, J. Res. Nat. But. Stand. (U.S.) 8_2 , 18

( 1977) .

3.

H. J. M. Hanley, W. M. Haynes and R. D. McCarty, The Viscosity and

Thermal Conductivity Coefficients for Dense Gaseous and Liquid Methane,

J. Phys. Chem. Ref. Data, Vol 6, No. 2, 597-609 (1977).

4.

H. J. M. Hanley, K. E. Gubbins and S. Murad, A Correlation of the

Existing Viscosity and Thermal Conductivity Coefficients of Gaseous and

Liquid Ethane, J. Phys. Chem. Ref. Data, Vol 6, No. 4, 1167 (1977).

5.

H. J. M. Hanley, P. M. Holland, K. E. Gubbins and J. M. Haile, J. Phys.

6 .

Chem. Ref. Data (in press 1978).

D. J. Evans and H. J. M. Hanley, Phys. Rev. (submitted).

6
Title - PROPERTIES OF CRYOGENIC FLUIDS

Principal Investigators . G. C. Straty, N. A. Olien, B. A. Younglove,

H. M. Roder, L. A. Weber, B. J. Ackerson, and D. E. Diller

Cost Center Numbers . 7360122, 7360124, 7360125

Sponsor Project Identification . NBS

Introduct ion . 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). Accurate thermophysical properties 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. We are now examining the data needs of a number of higher temperature industries

such as the synthetic natural gas (SNG) industry. This area of

technology as well as the liquefied petroleum gas (LPG) industry are logical extensions of the current LNG work. SNG mixtures can be

characterized as much more complex than natural gas, containing unlike

(including highly polar) molecules. Interactions between unlike

molecules are not well understood and the accurate data necessary to

quantitatively understand the interactions are lacking. The needs for

accurate predictive methods for SNG are essentially the same as LNG,

i.e., to reduce capital and operating costs and improve energy

ef f iciency

.

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. In addition we intend to

develop the capability to perform accurate PVT measurements on gaseous

mixtures and pure components at high pressures and above room temperature. 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; design, construct and performance

test a precision PVT apparatus for the region 250 - 900 K with pressures

to 35 MPa; and design, construct and performance test a transient

hot-wire thermal conductivity apparatus for the region 70 - 350 K with

pressures to 80 MPa.

Background . 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

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 been demonstrated.

7
Light scattering allows thermal diffusivity measurements in the region

where density fluctuations are relatively large, but accuracy drops

significantly as you pass outside the extended critical region. To

complement the scattering method, thermal conductivity measurements can

be made with more conventional techniques such as a hot-wire technique.

In the latter method a very small platinum wire is surrounded by the

fluid and a voltage pulse is applied to the wire. The temperature of

the wire is momentarily raised and the resistance increases. A series

of very closely spaced resistance measurements would describe the return

of the wire to equilibrium. These resistance vs. time measurements can

be related to the rate of heat dissipation in the surrounding fluid and

thus the thermal conductivity (provided convection heat transfer is

prevented )

The development of accurate mathematical models (equation of state) for

fluid mixtures requires accurate PVT data for the pure constituents and

binary mixtures of key molecular pairs. Experience with LNG has

identified the type and accuracy of the data required. In addition to

that, work on SNG at high temperatures is a logical follow-on to the low

temperature work on LNG. Typical constituents of raw SNG from coal via

the Lurgi process are: water - 50.2%; hydrogen - 20.1%; carbon

dioxide - 14.7%; carbon monoxide - 9.2%; methane - 4.7%; ethane - 0.5%;

hydrogen sulfide and others - 0.6%.

An apparatus has been assembled for laser light scattering spectroscopy

measurements on compressed and liquefied gases (76 - 300 K, 35 MPa).

The apparatus consists of a high pressure optical cell, a cryostat

refrigerated by means of 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 scanned Fabry Perot

interferometer for the measurement of the Doppler frequency shifts

associated with the scattering from propagating density (pressure)

fluctuations (Brillouin scattering).

Apparatus for photon-counting and digital autocorrelation has been

assembled, interfaced with computer facilities and programmed to enable

on-line data accumulation and analysis. Initial problems associated

with signal modulations from excessive building vibrations have been

solved by levitating the apparatus on an air suspension system. A

small, highly stable capacitor has also been designed, constructed and

installed inside the scattering cell to permit the dielectric constant

of the scattering fluid to be determined, which should allow more

accurate fluid densities to be obtained for use in the data analysis.

Apparatus tests on well characterized, strongly scattering, test fluids

have been made to verify data analysis programs.

Extensive thermal diffusivity data have been obtained for methane.

Measurements have been made along the coexistence curve, the critical

isochore, and critical isotherm. The measurements extend outside the

critical region as well as deep into the critical region. In the deep

critical region the effect of temperature gradients and impurities have

been investigated. Outside the critical region, these effects do not

affect measurements beyond experimental accuracy. The range of the

measurements extends from 150 K to 230 K and 3 mol/L to 22 mol/L. The

inaccuracy of the measurements is about 5% in the critical region,

nalysis of the

reporting

the results has been submitted to the Journal of Chemical Physics.

increasing to 10% or greater further away. A detailed

data and experimental error has been made and a paper fit

8
Some preliminary results on a mixture of 70% methane and 30% ethane were obtained very near the vapor-liquid critical point (plait point). The

results are interesting in that the thermal conductivity of the mixture

does not exhibit a critical anomaly whereas pure methane does exhibit an anomaly in the thermal conductivity as the critical point is approached.

The anomalous behavior of pure fluids and nonanomalous behavior of

mixtures is qualitatively and quantitatively in agreement with theoretical predictions (see preceding title 'Fluid Transport Properties'). We

hope to be able to perform more definitive measurements on hydrocarbon

mixtures in the near future.

7 . Program and Results .

7.1 Transient Hot-Wire Apparatus . The assembly of the apparatus is

complete and some preliminary measurements on air at low pressure and near room temperature have been made. Some difficulties have arisen due

to the limited precision of the Nova minicomputer. The machine carries

only 16 binary digits precision and must be run in double precision.

Operation in this mode, however, increases execution time by a factor of

three. The data acquisition on this type of apparatus dictates that a number of measurements be acquired in a little over two seconds. The

number of data points read in double precision is only marginally

adequate. Software means of circumventing this problem are now being

explored

7.2 Laser Light Scattering Measurements . During the past reporting

period some additional measurements were made on a 70% methane-30%

ethane binary mixture near the mixture critical point (plait point).

These results are not definitive enough to establish for certain the

existence or non-existence of an anomaly in the thermal conductivity.

What is needed is a systematic study of the behavior of a series of

well-characterized mixtures, especially as the concentration of one component goes to zero.

7.3 High Temperature PVT Apparatus . Adequate funding for this program

was obtained in December 1978; as a result design, procurement and

construction will proceed at a level of effort of approximately 1.5

staff-years/year. An automatic self-balancing thermometry bridge has

been obtained and checked out. Two precision quartz pressure

transducers (to 35 MPa) have been received and are installed in the NBS

Pressure Calibration System for calibration and long term stability

testing. Preliminary design of the experimental method and cell are in

progress as well as an examination of available high temperature baths.

A desktop calculator for data acquisition and experimental control is on order

8. Problem Areas . Light scattering has proven to be a valuable tool for

obtaining thermal diffusivity data on fluids. This is particularly true

in a broad temperature and density range around the critical point,

where more conventional experimental methods fail or are severely

limited. The intensity of the scattered light however decreases

drastically as one moves away from the critical region. Data accuracy

in this region becomes limited by the statistical nature of the

scattering process and the ability to maintain stability and precise

experimental parameters over the extended periods of time necessary for

data accumulation.

The difficulties outlined in 7.1 regarding the processing capabilities

of the present minicomputer persist in delaying the start of

experimental measurements at low temperature and high pressure.

9
9. Level of Effort . July 1 - December 31, 1978.

Staff-years expended

Equipment and/or Services Purchased

Approximate expenditures, total

0.8

6. 3K$

61 .0K$

10. Future Plans.

Objectives and Schedule: Quarter 1 2 Complete performance test transient

hot-wire thermal conductivity

apparatus. ^

Design, construct and performance

test high temperature-high

pressure PVT apparatus.

Laser light scattering measurements

on well-characterized binary

systems

.

References

1. B. J. Ackerson and G. C. Straty, Rayleigh Scattering from Methane, J.

Chem. Phys . 6_9, 1207-12 (Aug 1978 ).

2. B. J. Ackerson and H. J. M. Hanley, The Thermal Diffusivity of Methane

in the Critical Region, Chem. Phys. Lett. 5_3 , 596-8 (Feb 1978 ).

10
Title. PROPERTIES OF CRYOGENIC FLUID MIXTURES

Principal Investigators . M. J. Hiza, A. J. Kidnay (part-time), and

R. C. Miller (part-time)

Cost Center Numbers . 7360123, 7362289, 7368574

Sponsor Project Identification . NBS , NBS (OSRD) , GRI

Introduction . Accurate thermodynamic properties data and prediction

methods for mixtures of cryogenic fluids 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 prediction methods.

Objectives or Goals . The overall objectives of this project are to

provide critically evaluated data 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.

Background . A physical equilibria of mixtures research project was established in the Thermophysical Properties 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

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 nitrogen + methane, methane + ethane, etc.

11
7. Program and Results . The recent progress is summarized as follows:

a) Thermodynamic consistency tests and comparison of G

E values

derived from liquid-vapor equilibria data for methane + ethane

using different equations of state to correct for the non-ideality

of the vapor phase have been completed. The paper

1

’ discussing compilation, evaluation, and correlation of liquid-vapor

equilibria data for the methane + ethane system has been revised

accordingly. It has now been accepted for publication in the

Journal of Physical and Chemical Reference Data and should be in

print in late 1979.

b) A compilation, evaluation, and correlation of the liquid-vapor

equilibria for the methane + propane system, similar to that for

the methane + ethane system, has been completed. A first draft of

a paper reporting this work is nearing completion.

c) Graphs of K-values and equilibrium compositions for methane + propane based on selected data from b) are being prepared for the

LNG materials and fluids handbook.

8. Problem Areas . None

9. Level of Effort . July 1 - December 31, 1978.

Staff-years expended

Equipment and/or Services Purchased

Approximate expenditures, total

1 0 . Future Plans . Objectives and Schedule: Quarter 1 2 Complete draft of paper reporting

compilation, evaluation, and

correlation of liquid-vapor ^

equilibria data for methane + propane. Initiate editorial review.

Complete and report graphs of K-values

and equilibria compositions for

methane + propane.

Update bibliography on equilibrium

properties of fluid mixtures,

beginning with section on liquid-vapor.

References

0.7

2 . 7 K$

6 3 . 0K$

1. M. J. Hiza, R. C. Miller, and A. J. Kidnay, A Review, Evaluation, and

Correlation of the Phase Equilibria, Heat of Mixing, and Change in

Volume on Mixing for Liquid Mixtures of Methane + Ethane, J. Phys . Chem.

Ref. Data (being revised for publication).

2. M. J. Hiza, An Empirical Excess Volume Model for Estimating Liquefied

Natural Gas Densities, Fluid Phase Equilibria 2 , No. 1, 27-38 (1978).

3. R. C. Miller and M. J. Hiza, Experimental Molar Volumes for Some

LNG-Related Saturated Liquid Mixtures, Fluid Phase Equilibria 2 , No. 1,

49-57 (1978).

12
1. Title. DENSITIES of liquefied natural gas mixtures

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

2 . Cost Center Number . 7361574

3. Sponsor Project Identification . LNG Density Project Steering Committee;

American Gas Association, Inc., Project BR-50-11.

4. Introduction . Accurate density measurements and calculational 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 mathematical models 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 calculational methods were performed by independent

professionals

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 estimated imprecision of measurement is less than 0.02% and

the estimated inaccuracy is less than 0.15%.

7 . Program and Results .

7.1 Measurements . All measurements for this project have been

completed. The last series of measurements included the following:

(a) two methane-rich binary mixtures of CH 4 and iC^^g, (b) four

methane-rich binary mixtures of CH 4 and and (c) seventeen

methane-rich multicomponent mixtures of LNG components, including five

7- and 8 -component mixtures containing up to 0.44% pentanes. The data

have been analyzed and comparisons of the experimental densities with

calculated values from mathematical models developed for predicting LNG

densities have been made.

Papers describing the apparatus, experimental procedures, the data and

its analysis, and comparisons of the data with other experimental data

and calculated densities are being prepared.

13
7.2 Calculat ional Methods . Final optimization and modifications have

been made to the extended corresponding states model and to the hard

sphere model. Final optimization of the cell model will be made by Mel

Albright at Phillips Petroleum and some testing is still being made with

the Klosek and McKinley model.

Changes which were made to the extended corresponding states model and

the hard sphere model as a result of the new data were minimal and have

made very little difference in the calculated LNG densities.

The corresponding states model predicts all of the multicomponent

densities to within 0.1% with the exception of one point which shows a deviation of 0.11% which satisfies the original goal of the modeling

efforts

8. Problem Areas . None

I 9. Level of Effort. July 1 - December 31, 1978.

I Staff-years expended 0.3

Equipment and/or Services Purchased 7.5K$

Approximate expenditures, total 7.5K$

10. Future Plans . This program is complete apart from the publication of

the final results. There are three experimental papers in preparation,

an apparatus paper, a paper detailing the performance of the predictive

models and a final report encompassing all results of this six year

project
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 Numbers . 7363430, 7361430, 7362430

3. Sponsor Project Identification. Maritime Administration Misc. P.O.

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 255 K (0°F) to

228 K (-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. Objective . The objectives of the Phase II program are 1) to have the

four major plate producers supply three 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

evaluation of factors that influence heat affected zone toughness in

the improved steels.

6. 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 intial

phase of NBS 1 s recommended program, i.e., to survey the problem and

the technology available for its solution. On the basis of this sur- vey 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. Cost-sharing

contracts for the evaluation of the improved steels were awarded in

1975 to the three participating shipyards: Avondale Shipyards, Inc.,

Newport News Shipbuilding and Drydock Co. and General Dynamics-Qu incy

Shipbuilding Division. A similar contract was signed with Lukens

Steel Co. to evaluate Cb-treated V-051 steel with and without sulfide

shape control. The three participating shipyards and Lukens Steel Co.

completed the shipyard evaluation phase of the program in 1977. The

ABS steels with sulfide shape control had excellent toughness and the

HAZ toughness was improved, particularly for shielded metal arc (SMA)

and gas metal arc (GMA) welds. The most promising results for highheat-input welds were obtained with the Cb-treated V-051 steel with

sulfide shape control.

Follow-on contracts were awarded to the three participating shipyards

to further evaluate the most promising ship steels: ABS grades V-051

15
(Cb, SSC ) , V-062 ( SSC ) and (Cb, SSC). The work on these contracts

has been completed. The results indicate that each of the steels

retains satisfactory HAZ toughness at -51°C (at higher heat inputs

than conventionally used) providing the weld metal toughness exceeds

the 27J (20 ft lb) minimum.

7. Program and Results . During this reporting period, work on the final

report was started. No additional research was conducted.

8. Problem Areas . None

9. Level of Effort . July 1, 1978 to December 31, 1978

Staff-years expended 0.1

Approximate expenditures, total 4.0K$

10. Future Plans . An evaluation by Avondale Shipyards Incorporated of

submerged arc weldments with Linde Ml-88 wire will be completed. Upon

completion, the final report on the program will be finished.

16
1 . Title . CUSTODY TRANSFER - LNG SHIPS

Principal Investigators . W. C. Haight, R. J. Hocken, B. R. Borchardt,

R. G. Hartsock, R. C. Veale, J. D. Siegwarth, J. F. LaBrecque, and C. L.

Carroll

2. Cost Center Numbers. 7360460, 7361575, 7362575, 7363575, 7311573,

7311577

3. Sponsor Project Identification . LNG Custody Transfer Measurements

Supervisory Committee and Maritime Administration Misc. P.O.

#400-79005.

4. Introduction . In response to the requests from the U.S. shipbuilding

industry, NBS is independently examining the accuracies of LNG tank

cargo capacity tables and developing alternative survey techniques.

5. Objectives . The objectives of the program are to develop new techniques

for LNG transport tank calibration and to test the accuracy of present

calibration techniques as part of an overall study of custody transfer

methods aimed at increasing the accuracy of custody transfer

measurements

.

6. Background . Initial funding by the Maritime Administration (7360460)

supported some preliminary tests of calibration of spherical LNG ship

tanks. As a result of these measurements, the LNG Custody Transfer

Supervisory Committee and the Maritime Administration have funded

extension of the work to the membrane tanks and the free standing

prismatic tanks now under construction in U.S. shipyards.

7. Program . Techniques for accurately dimensioning prismatic tanks of the

membrane type have been developed by the Macrometrology Group at NBS.

The technique requires establishing a model of a solid of the same shape

as the tank just inside the tank walls using laser planes. Distances

from the laser planes to the wall are measured at a larger number of

points. The size and shape of the solid defined by the laser planes is

measured by a multiple redundant method so the accuracy of the measurement of the dimensions of the solid can also be determined. Measurements using this technique have been completed on the tanks of two ships

and three tanks of the third ship. Any disagreements between these

results and the results of the primary tank survey are smaller than the

allowed calibration uncertainty of + 0.2% of total volume.

Two of the free standing prismatic tanks have been tested for distortions resulting from lifting and loading them onto the ships. The

distortion detected was not significant relative to the accuracy

required of the photogrammetric survey.

An external laser plane survey method has been developed for a free

standing prismatic tank and the hardware is under construction.

The accuracy and precision of the photogrammetric tank survey method is

being tested with length standards. Invar tapes are being employed to

give accurate target separations for test lengths near the maximum

dimensions of the tank. Of the three tanks thus far completed, the

accuracy and precision of the photogrammetric measurements of the test

target separations indicate this survey technique meets volume accuracy

requirements. Measurements to check the photogrammetric survey have

been completed on ten tanks.

17
8 . Problem Areas. None

9. Level of Effort . July 1 - Dec. 31, 1978

Staff-years expended

Equipment and/or Services Purchased

Approximate Expenditures, Total

$1,500

$72,500

1.4

10. Future Plans . The checks of the surveys of the remaining three

membrane tanks will be completed. The laser plane dimensioning

technique will be applied to check the capacity of one of the free

standing prismatic tanks and to examine hydrostatic distortion effects.

The test tape measurements will continue on subsequent tanks to look

for possible survey distortions and to examine horizontal and vertical

calibration factors.

18
1. Tit le. HEATING value of flowing lng

Principal Investigators . J. A. Brennan

2. Cost Center Number . 7362570

3. Sponsor Project Identification . Pipeline Research Committee (American

Gas Association) PR-50-48.

4. Introduction This project will test instrumentation for making heat

value measurements on flowing LNG in actual applications. Information

from projects currently underway by Siegwarth (cost center 7367574) on densimeters, by Haynes and Hiza (cost center 7361574) on mixture

densities and by Richards (cost center 7363570) on LNG sampling will be

utilized where appropriate to provide state of the art information.

5. Objectives . The objective of this project is to measure total heating

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

measurements of flow, density and specific heating value. Flow

measurement requires 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 was used to evaluate the

response and integration of the individual elements of the heating value

measurement. Different compositions of LNG were tested to provide a range of densities and temperatures sufficient to determine any

dependencies. Sampling work was combined with the sampling project

(cost center 7363570) to better define the important criteria of this

phase of the measurement problem.

Flowmeter scalling work utilizes the cryogenic and water flow facilities

at NBS as well as private LNG peak shaving and import facilities.

7. Program and Results . All test instrumentation for the Southern Energy

Import Terminal has been installed and the recording equipment

connected. Preliminary tests of pressure, temperature, and flow were completed during the last quarter. Some problem areas were identified

and corrected. These instruments and the recording instrumentation have

all been checked out at the site.

The densimeter was not checked out during the preliminary tests because

the sensing head was not inserted into the LNG line. It was decided to

leave the densimeter retracted until after the facility had been in

operation for a period of time to prevent possible damage to the

densimeter during the start up procedures. The densimeter has now been

inserted and will be included during the next test.

8. Problem Areas . All known problem areas have been corrected.

9. Level of Effort . July 1 - December 31, 1978

Staff years expended 0.2 MY

Equipment and/or services purchases None

Approximate Expenditures, Total $7,200

10.

Future Plans . LNG flow tests will be run at Southern during the first

quarter of 1979.

19
1 . Title . |_NG density reference system

Principal Investigators . J. D. Siegwarth and J. F. LaBrecque

2. Cost Center Number . 7367574

3. Sponsor Project Identification . American Gas Association, Inc., Project

BR-50-10; Gas Research Institute.

4. Introduction . A density reference system has been developed to evaluate

the ability of commercially available instruments to measure densities

of LNG directly. Density is an essential measurement in determining the

total energy content of natural gas reservoirs.

5. Objectives . The object of this '"^search is to develop and supply

adequate calibration methods and calibration standards to densimeter

manufacturers and users for providing traceability of accuracy to field

density measurement systems.

6. Background . The density reference system project was initiated in 1973.

Since that time the reference system has been designed, constructed, and

is now in operation, evaluating commercial density metering systems.

Reports describing the density reference system and the results of the

tests of four commercial densimeters have been published. These reports

are

Siegwarth, J. D. , Younglove, B. A., and LaBrecque, J. F., Cryogenic

fluids density reference system: provisional accuracy statement.

National Bureau of Standards (U.S.) Technical Note 698, 24 pages (1977),

and

Siegwarth, J. D. , Younglove, B. A., and LaBrecque, J. F., An evaluation

of commercial densimeters for use in LNG, National Bureau of Standards.

(U.S.) Technical Note 697, 43 pages (1977).

The work has also been presented in the following papers:

Siegwarth, J. D. , Younglove, B. A., and LaBrecque, J. F., Test of

densimeters for use in custody transfer of LNG, Proc 53rd International

School of Hydrocarbon Measurement, Normon, Oklahoma (1978).

Parrish, W. R. , Brennan, J. A., and Siegwarth, J. D. , LNG custody

transfer research at National Bureau of Standards, American Gas

Association Operating Section Proc. T243 (1978).

7. Program and Results . The tests on the seven Archimedes densimeters were completed. The results of the tests suggested some modifications to the

instruments to improve both the repeatability and calibration of the

instrument.

The Archimedes densimeter calibrated for a transfer was recalibrated. A

0.1% shift in calibration was encountered.

The redesign of the DRS has been completed. The parts have been built

and assembly of the new system is in progress.

An enlarged version of this redesign system is under construction by an LNG importer to serve as a calibration system for ship board

densimeters

20
8 .

9.

10 .

Problem Areas. The recent densimeter tests have shown that LN? is not

the best choice of a calibration fluid for densimeters to be used in

LNG . Better calibration techniques for commercial instruments are needed

.

Level of Effort . July 1 - Dec. 31,

Staff-years expended

Equipment and/or Services Purchased

Approximate Expenditures, Total

1978

0.8

$ 4,000

$48,000

Future Plans . The rebuilding is expected to be completed about mid

February and a vibrating cylinder densimeter of a new type will be

tested at the same time the new DRS is checked out. A transfer standard

will be sent to Gaz de France, Paris, when the calibration problems with

the Archimedes densimeter are solved. The DRS will be used to check the

calibration of the densimeter in the industrial calibration system

presently under construction.

21
Title. LNG SAMPLING MEASUREMENT STUDY

Principal Investigators . R. J. Richards, J. F. LaBrecque, and J. A.

Brennan

2. Cost Center Numbers . 7363570

3. Sponsor Project Identification . Pipeline Research Committee (American

Gas Association) PR-50-94.

4. Introduction . Composition is used to determine both the heating value

and the quantity (through density) of LNG shipments. Thus, any error in

composition doubles when calculating the total heating value and dollar

value of a LNG tanker cargo. Compositions are determined by sampling

LNG, on either a batch or continuous basis, and analyzing the vaporized

mixture. Although several sampling techniques exist, none have received

a widespread acceptance in the LNG industry. Also, a standard technique

has not been established for analyzing the vaporized sample.

5. Objectives . The objectives of this work are the same as the last

reporting period with emphasis on vaporizer and accumulator design.

6. Background . This work was performed because there is a need to

determine the best means for obtaining the composition of LNG shipments.

Current LNG buying contracts include specifications on when and how many

liquid samples are to be taken but omit the sampling technique to be

used. The evaluation of sampling techniques by NBS is expected to lead

to the acceptance of the most accurate composition determination method

by all parties involved in LNG custody transfer.

7. Program . Based on previous work, the two factors preventing development

of a general design are sampling rate and vaporizer-accumulator design.

Test results showed that the precision of the system diminishes below a certain sampling rate. Attempts to correlate sampling rate with the

limited range tested for the other variables failed. However, by process

of elimination, the most likely factors causing the effect of sampling

rate on precision are probe size, line size between the probe and

vaporizer and heat leak. All of these variables are being evaluated in

a laboratory apparatus, where the operating variables are controlled

closely and mixtures of known composition are used.

I Previous tests demonstrated that using a simple tube-vaporizer required

the use of an accumulator to average out composition fluctuations. It was surmised that a non-equilibrium vaporization process was causing the

fluctuations. New experiments have shown that non-steady flow into the

vaporizer was also an important contributor to the problem. Using

vaporizers of different designs and insuring single phase flow into the

vaporizer, it has been possible to operate the sampling system without

an accumulator with much less variation in composition.

Although improvement in sampling system performance has been significant, the use of an accumulator still gives the most consistent

results. It may be possible to reduce the accumulator size by better

flow control to the vaporizer and more controlled vaporization.

Reducing the accumulator size would decrease the systems time constant

thus making it more responsive to actual changes in composition. These

parameters will be investigated during the final phase of the program.

8. Problem Areas. None.

22
9 . Level of Effort . July 1 - December 31, 1978

Staff years expended 0.8

Experiments and/or services purchased None

Approximate Expenditures, Total $34,000

0. Future Plans . Complete work on alternate vaporizer and accumulator

designs and write a final report.

23
1 . Title . SURVEY OF CURRENT LITERATURE ON LNG AND METHANE

Principal Investigator . Neil A. 01 ien

2. Cost Center Number . 7369574

3. Sponsor Project Identification . Gas Research Institute Grant No.

5010-362-0019 and American Gas Association, Inc., 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 systematic

review of the current publication scene is 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 four bibliographies involved: methane

properties, methane mixtures properties, processes and equipment

involving methane and LNG, and patents relating to methane and LNG

technology. These four will be updated annually.

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 330 primary publications and nearly 25

secondary publications. Of these, approximately one-third are directly

related to LNG. In addition, we have increased our coverage of the

energy field to include SNG (coal gas, hydrogen, etc.). Much of this

information is also pertinent to LNG and as such is listed in our

LNG-related 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 . Four issues of the LNG Quarterly are prepared each

year and distributed. There are now 121 subscriptions going to AGA

Member Companies and 155 to other subscribers.

The four comprehensive bibliographies mentioned in section 5 have been

reviewed and shortened, and more selective bibliographies have resulted.

The latest versions were completed as of January 21, 1977.

B- 1525 THE THERMOPHYSICAL PROPERTIES OF METHANE AND DEUTERO-METHANE

IN THE SOLID, LIQUID AND GASEOUS PHASES - A SELECTED BIBLIOGRAPHY. Indexed by property, phase and author, 100 pages

(Jan 1977) . ($10.00)

.

B- 15 26 THE THERMOPHYSICAL PROPERTIES OF METHANE MIXTURES - A SELECTED

BIBLIOGRAPHY. Indexed by property, system and author,

166 pages (Jan 1977). ($15.00).

24
B-1524 PROCESSES AND EQUIPMENT INVOLVING LIQUEFIED NATURAL GAS AND

METHANE - A SELECTED BIBLIOGRAPHY. Indexed by subject and

author, 285 pages (Jan 1977). ($25.00).

B-1527 PATENTS RELATING TO METHANE AND LNG TECHNOLOGY - A SELECTED

BIBLIOGRAPHY. Indexed by author, 150 pages (Jan 1977).

($15.00)

.

Over the past seven years we have distributed over 500 copies of these

and the comprehensive bibliographies.

The size of these has grown to the extent that their usefulness is

limited, therefore it was decided that they would not be updated and a series of more specialized bibliographies would be made available. The

following list gives those currently available. Additional topics will

be added as necessary. To date 70 copies of the following have been

distributed.

B- 15 28

B-1529

B-1530

B-1531

B-1532

B- 1533

B- 15 34

LIQUEFIED NATURAL GAS STORAGE INCLUDING INSULATION SYSTEMS.

1181 references, indexed by author and subject, 210 pages

( $20.00)

.

LIQUEFIED NATURAL GAS PEAKSHAVING AND SATELLITE OPERATIONS.

221 references, indexed by author, 36 pages ($10.00).

LIQUEFIED NATURAL GAS STRATIFICATION AND ROLLOVER. 38

references, indexed by author and subject, 10 pages ($5.00).

LIQUEFIED NATURAL GAS SAFETY INCLUDING SPILLS. 368

references, indexed by author and subject, 72 pages ($10.00).

LIQUEFIED NATURAL GAS PIPELINES AND TRANSFER LINES. 226

references, indexed by author, 44 pages ($10.00).

LIQUEFIED NATURAL GAS SHIPS, BARGES AND OVERWATER TRANSPORTATION. 805 references, indexed by author, 138 pages ($15.00).

LIQUEFIED NATURAL GAS VAPORIZORS INCLUDING COLD UTILIZATION.

330 references, indexed by author and subject, 58 pages

($ 10 . 00 ) .

B- 1535 LIQUEFIED NATURAL GAS HEAT TRANSFER. 155 references, indexed

by author, 34 pages ($10.00).

B-1536 LIQUEFIED NATURAL GAS LIQUEFACTION AND REFRIGERATION. 551

references, indexed by author, 94 pages ($15.00).

B-1537 LIQUEFIED NATURAL GAS ECONOMIC FACTORS. 470 references,

indexed by author, 84 pages ($15.00).

B- 15 38 LIQUEFIED NATURAL GAS OVERLAND TRANSPORTATION. 76 references,

indexed by author, 15 pages ($5.00).

B- 15 39 LIQUEFIED NATURAL GAS PATENTS. 747 references, indexed by

author and subject, 119 pages ($15.00).

B-1540 LIQUEFIED NATURAL GAS INSTRUMENTATION. 85 references, indexed

by author and subject, 23 pages ($5.00).

8. Problem Areas. None.

25
Level of Effort . July 1 - December 31, 1978.

0.25

2 . 2K$

7 . 5K$

Staff-years expended

Equipment and/or Services Purchased

Approximate expenditures, total

10. Future Plans . Issue 78-4 was delivered to the printer the second week

of January and should be distributed before the end of January.

26
1. Title , liquefied natural gas technology transfer

Principal Investigators . D. E. Diller, H. M. Ledbetter, and N. A.

Olien

2. Cost Center Numbers. 7360403, 7361403, 7364574, 7368574, 7362287,

7360461, 7360594

3. Sponsor Project Identification . Maritime Administration, Miscellaneous

Purchase Order No. 400-79005; American Gas Association, Inc. Project

BR-50-10; Gas Research Institute; NBS Office of Standard Reference

Data.

4. Introduction . The liquefied natural gas program at the Thermophysical

Properties Division of NBS Boulder represents an investment by industry

and government agencies of over $5 million over the past six years.

This investment was designed to develop reference quality properties

data for both fluids and materials and instrumentation and measurement

technology for the use of the LNG and related industries. Information

developed under this program must be transmitted to the ultimate user in

a timely and useful format. The classical publication methods of NBS

most certainly provide the scientist and research engineer information

in a form most useful to the academic or near academic community.

However, as a result of extensive assessments of user requirements, it was found that an additional effective mode for technology transfer

would be an LNG Materials and Fluids User's Manual. A complete outline

and planned table of contents have appeared in previous semiannual

reports. The Maritime Administration of the Department of Commerce and

the American Bureau of Shipping have agreed to sponsor the first year's

efforts on the materials section, and the American Gas Association, Inc.

and the NBS Office of Standard Reference Data have agreed to sponsor the

section on fluids and fluid mixtures. The project was begun on April 1,

1976.

5. Objectives or Goals . The Liquefied Natural Gas Materials and Fluids

User's Manual will provide a method of quick dissemination of property

data and related information for the effective generation, utilization

and transportation of LNG. The object is to improve technology transfer

from the current NBS Thermophysical Properties Division LNG physical

measurements program to the users, including federal agencies, the

states and industry. For the purpose of this data book, liquefied

natural gas is defined as a cryogenic mixture (at less than

approximately 150 K) of hydrocarbons, predominantly methane, with less

than a total of 20% of the minor components ethane, propane, iso and

normal butane, and nitrogen as an inert contaminant. LNG materials will

be those associated with the liquefaction, transport and storage of

liquefied natural gas.

6. Background . The User's Manual is only one of a number of information

dissemination methods used to provide workers in the liquefied natural

gas (LNG) industry with properties data of known quality in a format

consistent with the requirements of the intended user. In the case of

the LNG User's Manual the intended audience is the field engineer, plant

manager, ship designer or process engineer interested in a ready

reference of assessed quality for data to be used in conceptual design,

process monitoring, process analysis, and intercomparisons where

precision and accuracy are secondary to specific problem solutions. The

hierarchy of accuracy and precision will be defined and traceable

through references to scientific and engineering literature.

Data are classified into three groups by the NBS Thermophysical

Properties Division.

27
Group 1 . Data which have been generated experimentally by NBS , or have

been assessed, evaluated or experimentally verified by NBS.

Group 2 . Data which have been assessed and evaluated by NBS.

Group 3 . Data available in the scientific engineering literature

through the NBS Cryogenic Data Center or elsewhere. No NBS evaluation

or assessment has been made at this date.

In general, most data included in the LNG User's Manual will be from

groups 1 and 2. Few new assessments or correlations are anticipated or required for this work.

Data will be presented primarily in graphical form. Tables and analytical expressions will be used only where absolutely necessary. Graphs

and charts will be in loose-leaf form for ease of updating and

additions. This form will also allow immediate implementation for data

already available under the NBS LNG program and will provide a convenient format for the output of data from existing projects. The

User's Manual will not be a substitute for traditional publications in

the scientific literature where measurement science, technique,

precision and accuracy are paramount, but will provide the data and

references for the necessary assessment by the user. The publication of both graphical and tabular data will be in a dual

system of physical units. These units will be the traditional LNG

industry British System of BTU , pound, degree Fahrenheit and the SI

system of joule, kilogram and kelvin. It is the intent to give equal

weight to each system of units.

7. Program and Results . The first edition of the User's Manual became

available for distribution in September 1977. A complete description

and ordering information are included as part of this report. About 550

copies have now been distributed to sponsors and purchasers. New orders

are currently coming in at the rate of about ten per week. The first

supplement to the User’s Manual is printed out 210 copies have been

distribution thus far. The first supplement contains 31 graphs of

revised, updated and new material on the properties of structural metals

and alloys (aluminums, nickel steels and stainless steels); 40 graphs on thermal insulations (polystyrene foams, polyurethane foams, polyvinyl

chloride foams, balsa, perlite, cellular glass and glass fiber); 15

graphs and 3 wall charts on pure LNG components (ethane); and 9 sheets

on binary and multicomponent mixtures of LNG components. The first

supplement also contains 46 pages of materials specification tables and

38 pages of additional narrative and other descriptive materials.

8. Problem Areas . None.

9. Level of Effort . July 1 - December 31, 1978.

Staff-years expended 1.2

Equipment and/or Services Purchased 16.8K$

Approximate expenditures, total 91.8K$

10. Future Plans . Work on the second supplement is in progress. Propane

graphs and thermodynamic property charts have been prepared. Additional

graphs on mixtures of LNG components are nearly complete. Graphs on the

properties of structural composites and aggregates (with emphasis on concretes) are underway. The second supplement is expected to be ready

for distribution by September 1979. No additional supplements are planned at this time.

28
1. Title . 01 ML JOINT SECRETARIAT ON LNG MEASUREMENTS

Principal Investigators . Douglas B. Mann and James A. Brennan, NBS and

T. L. Hillburn, Phillips Petroleum Company.

2. Cost Center Number . 7360290

3. Sponsor Project Identification . American Gas Association, Inc.,

NBS-Office of International Standards; and NBS.

4. Introduction . The liquefied natural gas program of the National Bureau

of Standards Cryogenics Division has, over the past five years, provided

the gas industry and interested Government agencies with properties data

on materials and fluids, instrumentation, and measurement assistance in

supplementary fossil energy supply. Support of this program by the

American Gas Association, Inc., and Federal Government agencies such as the Maritime Administration (MarAd), NASA, GSA, Federal Power Commission

and the NBS-Office of Standard Reference Data has provided a basis for

the national acceptance of the results of the NBS LNG program. Through

the U.S. membership in the International Organization of Legal

Metrology there exists, at the present time, an opportunity to extend,

internationally, the utility of data and measurement practice developed

under our joint Government/industry program. We have been requested (by

OIML membership) to establish a LNG Measurement Secretariat within OIML

which, if implemented, would provide a significant international forum

for the results of our joint work. It is believed that a joint

Secretariat with the LNG industry would provide the most effective means

of accomplishing these objectives.

5. Objectives or Goals . Our objective is to accomplish the following goals

within the next three years.

a) To establish U.S. (NBS) thermophysical properties data for LNG as the standard data in international usage.

b) To establish U.S. (NBS) materials property data used in fabrication

and construction of LNG facilities (liquefiers, storage, transport) as the standard data in international usage.

c) To establish U.S. (NBS) approved measurement technology and

instrumentation as related to LNG (pressure, temperature, density,

liquid level, flow) as the standard in international LNG trade. The

precedent has been established with the successful completion of the

joint NBS-CGA cryogenic flow measurement program which has resulted in

the adoption of a cryogenic flow measurement code by the National

Conference on Weights and Measures. We wish to extend this code on an international basis.

d) To establish and maintain the leadership of U.S. science,

engineering, and industry in the research, technology, manufacture and

marketing of instruments and measurement systems for liquefied natural

gas

6. Background . OIML was founded in 1955 to promote intergovernmental

cooperation in the field of legal metrology which relates to the

compatibility of standards of measurement and the legislation and

government regulations which may affect such standards of measurement.

OIML recommends uniform international requirements for scientific and

measurement instruments used in industry and commerce and works out

model laws and regulations for consideration by member nations; and, in

29
addition, serves as a center of documentation and information exchange

in legal metrology. At present, 43 nations are members of this

intergovernmental organization.

The United States joined OIML in 1972 (the Senate by resolution of

August 11, 1972, gave its advice and consent to the accession of the

U.S. to the convention establishing OIML). The responsibility for

managing U.S. participation in OIML was assigned to the Department of

Commerce and has since been delegated by the Department to the National

Bureau of Standards (NBS). Under the general guidance of the Department

of State and the Secretary of Commerce, NBS is directly responsible for

formulating and implementing U.S. policy towards OIML. U.S. participation in the organization is deemed important for two reasons: First,

to protect and enhance some $1 billion worth of scientific and measurement instruments exported each year by U.S. firms and to ensure equity

in the trade of commodities measured by these instruments; and second,

to maintain the U.S. as the world leader in the field of metrology.

In the spring of 1975 at a meeting in Paris of the International

Committee of Legal Metrology, the French and U.S. representatives

discussed the possibility of creating a new Reporting Secretariat No. 15 on "Liquefied Natural Gas (LNG) Measurement." The U.S. representative,

W . E. Andrus, Jr. of NBS, agreed to explore the possibility with U.S.

industry and interested government agencies. These discussions resulted

in a decision to propose a joint Secretariat with the American Gas

Association and NBS-Cryogenics Division in order to best accomplish the

tasks. These conclusions were reached during several meetings extending

through the latter part of 1975 and early 1976. During the summer of

1977, representatives of NBS met with PTB (West Germany) and SIM

(France) to discuss the proposed scope and to explore expansion of the

effort to include cryogenic fluids in general. Results of those

discussions indicate some resistance to including different physical

measurements (flow, density, etc.) under a single recommendation for a specific group of fluids.

The proposed plan and scope were presented at the meeting of The

Advisory Committee for International Legal Metrology held at NBS-Boulder

in September. The committee encouraged NBS to proceed with the present

scope and to continue to explore the possible inclusion of other

cryogenic fluids.

Program and Results . A revised work plan for cryogenic fluids was generated by the technical associates Douglas B. Mann of NBS and T. L.

Hillburn of the Phillips Petroleum Co. representing A.G.A. and API. The

scope of the work plan included instrumentation and procedures for the

custody transfer measurements of pressure, temperature, density, liquid

level, flow and calorific value of liquefied atmospheric and natural

(hydrocarbon) gases having pure fluid or mixture normal boiling points

of less than 150 K. Recommendations will be limited to establishing

total mass and, where applicable, total heating value. Fluids and fluid

mixtures considered will be limited to commercially important liquefied

atmospheric gases, oxygen, nitrogen and argon and the primary components

of liquefied natural gas, methane, ethane, propane, iso- and normal

butane and pentane.

Flow measurements of pure cyrogenic fluids will be the first of the

recommendations generated under the proposed work plan. This will be

accomplished by combining the existing U.S. and European codes for flow

measurements. A working group has been formed of interested parties and

the first draft of this recommendation should be ready for review by
January of 1980. These plans are subject to funding during the present

fiscal year.

8 . Problem Areas. None

9 . Level of Effort . Staff-years expended

Equipment and/or Services purchased

Approximate Expenditures $15,000

0.25

0.00

10. Future Plans . A first draft recommendation will be prepared by NBS as a simple combination of the two existing codes. This draft will be

distributed to the four members of the working group for review. The

revised first draft will then be submitted to the NBS-OIML representatives for OIML distribution.

31
NBS-114A (REV. 9-78)

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 79-16032.0ov^t No,

i i

m

4. TITLE AND SUBTITLE

LIQUEFIED NATURAL GAS RESEARCH AT THE

NATIONAL BUREAU OF STANDARDS

5. Publication Date February 1979

$. Performing Organization Code

7. AUTHOR(S) 8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, DC 20234

10. Project/Task/Work Unit No.

11. Contract/Grant No.

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City, State, ZIP)

See page ii

13. Type of Report & Period Covered

1 July 1978-31 Dec 1978

15. SUPPLEMENTARY NOTES

| | Document describes a computer program; SF-185, FIPS Software Summary, is attached.

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.) The objective of this report is to:

1. provide all sponsoring agencies with a semiannual report on the

activities of their individual programs;

2. inform all sponsoring agencies on related research being conducted at

the Themophysical Properties Division;

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 work is supported by NBS and seven other agencies and represents the

collective expenditure of $400,000 during the 6-raonth reporting period. The

contents of this report augment quarterly progress meetings for certain of our sponsors and provide a perspective which is missing when the parts are viewed

individually. 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 .

During this reporting period we have issued the first supplement to the

"LNG Material and Fluids" Users Manual.

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)

Cryogenics; liquefied natural gas; measurement; methane;

properties; research.

18. AVAILABILITY Unlimited 19. SECURITY CLASS

(THIS REPORT)

21. NO. OF

PRINTED PAGES

T^I For Official Distribution. Do Not Release to NTIS UNCLASSIFIED

| | Order From Sup. of Doc., U.S. Government Printing Office, Washington, DC

" 20402, SD Stock No. SN003-003-

20. SECURITY CLASS

(THIS PAGE)

22. Price

| | Order From National Technical Information Service (NTIS), Springfield, VA. 22161 UNCLASSIFIED

U.S. GOVERNMENT PRINTING OFFICE: 19 79-0-67 7-0 7 2/1 24 9 USCOMM-DC