Propane GPA 2140-97 attach 2.pdf

GPA Standard 2140-97

Liquefied Petroleum Gas

Specifications and Test Methods

Adopted as Recommended Procedures 1931

Revised 1940-1947-1948-1951-1955-1957-1959-1960-1962-1968

1970-1973-1975-1977-.1980-1984-1986-1988-1990-1992-1996-1997

Reprinted 1996

Gas Processors Association 6526 East 60th Street

Tulsa. Oklahoma 74145

• TABLE OF CONTENTS

Disclaimer. .. . .. , . . .. .. .. . .. ii11 .. • .. • '" .. • • .. • " " " .. • .. • • .. • • • .. • .. " .. .. .. .. .. " • • .. .. .. .. .. .. .. .. .. " .. .. • .. .. • • .. • • • .. .. .. .. .. .. .. .. " .. • .. .. " .. '" " .. .. t

Foreword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • • . . . . . . . . . • . . . . • . . . . ii

ASTM D-1657-89: Density or Relative Density of Light Hydrocarbons

ASTM D·1838-91: Copper Strip Corrosion by Liquefied

ASTM 0.2163-91: Analysis ofLiquefied Petroleum <LP) Gases and

GPA Specifications for Liquefied Petroleum Gases .•

ASTM D-1265-92: Sampling Liquefied Petroleum Gases

ASTM D-1267-95: Vapor Pressure ofLiquefied Petroleum Gases by Pressure Hydrometer ...............................................•.......•

ASTM D-1837-94: Volatility of Liquefied Petroleum Gases ........... " ........................•..... , ... 14

Petroleum Gases .....................•

ASTM D-2158-92: Residues in Liquefied Petroleum Gases

Propylene Concentrates by Gas Chromatography

ASTM D-2713-91: Dryness ofPropane (Valve Freeze Method) ..............•...•...••..........•........•. 29

ASTM D·2784·92: Sulfur in Liquefied Petroleum Gases

(OXYhYdrogen Burner or Lamp) ....•........•..................................••

GPA 2174-93: Obtaining Liquid Hydrocarbon Samples Using a Floating

Piston Cylinder .......................•..•....•..............•

Propane Dryness Test (Cobalt Bromide Method) ...............•

Note: ASTM test methods included in this publication have been adopted by GPA, and are included through a right-to-reprint agreement with, and by special permission of, the American Society of Testing and Materials, 1916 Race Street, Philadelphia, Pa.

DISCLAIMER

GPA publications necessarily address problems of a general nature and may be used by anyone desiring to do so.

Every effort has been made by GPA to assure accuracy and reliability of the information contained in its publications. With respect to particular circumstances, local. state, and federal laws and regulations should be reviewed. It is not the intent of GPA to assume the duties of employers, manufacturers, or suppliers to warn and properly train employees, or others exposed, concerning health and safety risks or precautions.

GPA makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal regulation with which this publication may conflict, or for any infringement of letters of patent regarding apparatus, equipment, or method so covered.

FOREWORD

These specifications generally define physical properties and characteristics of liquefied petroleum gases (LP-Gas) which make them suitable for private, commercial, or industrial applications. These specifications do not purport to specifically define all possible requirements to meet all possible applications. Therefore the user is cautioned to exercise judgement in/ormulatingfinal specifications/or specific applications.

The Gas Processors Association, its management, and supporting companies claim no specific knowledge of how manufacturers and users will produce, handle, store, transfer or consume the products defined herein and therefore, are not responsible for any claims, causes of action, liabilities, losses or expenses resulting from injury or death of persons and/or damage to property arising directly or indirectly from the use ofLP-Gas or these specifications relating to LP-Gas.

LP-gases are composed of hydrocarbon compounds, predominately propane and butane, produced during the processing of natural gas and also in the conventional processing of crude oil. The composition of LP-gases may vary depending on the source and the ratios of propane and butane content. They exist as gases at atmospheric pressure and ambient temperatures, but are readily liquefied under moderate pressures for transportation and utilization

There are many uses for LP-gases, the major ones being as (1) petrochemical, synthetic rubber, and motor gasoline feedstocks, and as (2) commercial, domestic and industrial fuel. The following may be accepted as a general guide for the common uses for the four fuel types covered by these specifications:

Commercial Propane is the preferred. fuel type for domestic, commercial and industrial fuels. It is also a suitable fuel for low severity internal combustion engines.

Commercial Butane is used principally as feedstock for petrochemicals, synthetic rubber, and as blending stocks or feedstocks in the manufacture of motor gasolines. Its use as a fuel is generally limited to industrial applications where vaporization problems are not encountered; however, small quantities are used as domestic fuel.

Commercial Butane-Propane Mixtures cover a broad range of mixtures, which permits the tailoring of fuels or feedstocks to specific needs.

Propane HD-5 is less variable in composition and combustion characteristics than other products covered by these specifications. It is also suitable as a fuel for internal combustion engines operating at moderate to high engine severity.

Additional Considerations

Odorization

For certain applications including, but not limited to, use of LP-gas for residential and commercial fuels, users of LP gas should be aware of additional requirements of other standards. principally NFP A 58 "Storage and Handling of Liquefted Petroleum Gases"(I) and other regulations (2). NFPA 58 has been adopted widely by local, state and other regulatory bodies in the form oflaws, ordinances, or regulations governing the safe storage, transportation, and use ofLP-gas as fuels.

Among other requirements, NFPA 58 (Sec. 14.1.1) stipulates that LP-gases "be odorized by the addition of a warning agent of such character that they are detectable, by a distinct odor, down to a concentration in air of not over one-fifth the lower limit of flammability". NFP A notes that "ethyl mercaptan in the ratio of 1.0 lb. per 10,000 gallon of liquid LP·Gas has been recognized as an effective odorant. Other odorants and quantities meeting the requirements of 1-4.1.1 may be used.

Research on odorants has shown that thiophane in a ratio of at least 6.4 lbs. per 10,000 gallon of liquid LP-Gas may satisfy the requirements of 1-4.1.".

Ammonia

NFPA 58 also states that LP-gas stored or used in systems within the scope of this standard "shall not contain ammonia" . Although ammonia is not a naturally occurring contaminant of LP-gas, certain industry practices, including the dual use of transportation or storage equipment, may inadvertently result in contamination of LP-gas by ammonia. When such a possibility exists, users should test for the presence of ammonia in propane and take appropriate means to eliminate ammonia from the system, since such contamination may cause stress corrosion cracking of copper bearing alloys in the distribution system.

ii

Fluorides

• Certain refining processes can, during process upset or malfunction, result in contamination of LP-gas by fluoride compounds. Such contamination can be extremely destructive in the distn1>ution and end user system. In addition, the combustion products of fluorides can cause physical damage to property and personal health. Similarly, fluorocarbons, such as certain refrigerants, can contaminate gas through dual use of storage or tankage facilities. Such contamination is rare but, if the possibility exists, users of LP-gas should take extreme precautions to insure the absence of fluorides.

Sulfur Compounds

Sulfur compounds such as elemental sulfur, hydrogen sulfide, and carbonyl sulfide may be naturally occurring contaminates of natural gas from which LP-gas is derived. The Copper Strip Corrosion Test (ASTM D-1838) and the Total Sulfur Test (ASTM D-2784) assure limitation of objectionable sulfur compounds to prevent corrosion of equipment containing brass fittings and copper tubing. However this test method is not applicable to liquefied petroleum gases containing corrosion inhibitors or any other agents which diminish the corrosivity of the sample to the copper strip.

Methanol

There is a possibility that a small amount of methanol may be present in LP-Gas. If methanol is present, ASTM I)..

2713. "Standard Test Method for Dryness of Propane-Valve Freeze Method" is not applicable for detennining the dryness of propane type products.

Residual

LP-gas as produced is nonnally free of residual matter, which includes those heavier hydrocarbons boiling above 100 OP, including any solid foreign materials. If residuals are present as shown by ASTM D-2158, "Standard Test Method for Residues in LP..oas", and are in excess of the amount allowed by these specifications, such material may cause improper operation ofregulators, vaporizers, or combustion apparatus.

(I) NFPA 58 "Storage and Handling Uquefted. Petroleum Gases"-National Fire Protection Association, Battery-March

Park, Quincy, MA 02269

(2) Code of Federal Regulations, CPR 49:173.315(b)(1)

Other Trace Constituents

Trace constituents other than those mentioned above can also be present in LP-gas as a natural occurrence or from processing. These may include olefins. mercury. and arsenic. Users of LP-gas with processes that can be harmed by these constituents are advised to take appropriate precautions to prevent damage to catalysts and/or process equipment from these trace materials .

iii

GPA LIQUEFIED PETROLEUM GAS SPECIFICATIONS

Product Deslguation

Product CharacteristIcs

Composition

Vapor pressure at HlOoF, psig. max at 37.SoC, kPa, max

Volatile residue:

temperature at 95% evaporation.

deg. F, max deg. C, max or butane and heavier, liquid volume percent max pentane and heavier, liquid volume percent max............."".

Residual matter:

residue on evaporation of 100 mI. max oil stain observation

Corrosion, copper strip, max

Total sulfur, ppn1w...................................................................m

Moisture content

Commercial Propane

Predominantly propane and/or propylene

-37 -38.3

O.OSml pass (l)

No.1 pass

Commercial Butane

Predominantly butanes and/or butylenes

No.1

Commercial B-P

Mixtures

Predominantly mixtures of butanes and/or butylenes with propane and/or propylene

20S

2.2 2.0

No.1

Propane

HD·5

not less than 90 liquid volume per cent propane; not more than. 5 liquid volume percent propylene

-37 -38.3

O.OSml pass (1)

No.1 pass

Test Methods

ASTM D-2163-91

ASTM D-1267-95

ASTM D-1837-94

ASTM D-2163-91

ASTM 0.2163-91

ASTM D-2158-92

ASTM D-2158-92

ASTM D-1838-91

(Note A)

ASTM D-2784-92

(Note B)

GPAPropane Dryness Test (Cobalt Bromide) or D-2713-91

Free water conterlt none none

(1) An acceptable product shall not yield a persistent 011 ring when 0.3 ml of solvent residue mixture Is added to a filter paper In 0.1 Increments and examined In daylight after 2 minutes as described In ASTM 0-2158.

NOTE A: this method may not accurately determine the corroslvity of the Hquefied petroleum gas If the sample contains corrosion Inhibitors or other chemicals which diminish the corrosivity of the sample to the copper slrlp. Therefore, the addition of such compounds for the sole purpose of biasing the test Is prohibited.

NOTE B: Be advised that the tolal sulfur nmlts In these specifications do Include sulfur compounds used for stenchlng purposes.

Nt AmerIcan National Standard4D~ Designation: D 1265 - 92

Standard Practice for Sampling Liquefied Petroleum (LP) Gases (Manual Method)1

This standard is issued under the fixed designation D 1265; the number immediately rollowing the designation indicates the year or original adoption or, in the ease orrevision, the year oflast revision. A number in parentheses illdicates the year of\ast reapproval. A supCISCript epsilon (E) illdicates an editorial cbange since the last revision or reapprova1.

1. Scope

1.1 This practice covers the procedures for obtaining

representative samples of liquefied petroleum gases such as propane, butane, or mixtures thereof, in containers other than those used in laboratory testing apparatus. These procedures are considered adequate for obtaining representa tive samples for all routine tests for LP gases required by Specification D 1835 except analysis by Test Method D 2163. They are not intended for obtaining samples to be used for compositional analysis. A sample procedure that avoids changes in composition must be used for composi tional analysis.

NOTE I-Practice D 3700 describes a recommended method for obtainins a representative sample of a hydrocarbon fluid and the subsequent preparation of that sample for laboratory analysis.

1.2 This standard does not purport to address all oj the

softty problems, if any, associated with its use. It is the responsibility ojthe user ojthis standard to establish appro priate safety and health practices and determine the applica bility ojregulatory limitatiOns prior to use.

2. Referenced Documents

2.1 ASTM Standards:

D 1835 Specification for Liquefied Petroleum (LP) Gases2

D 2163 Test Method for Analysis of Liquefied Petroleum (LP) Gases and Propene Concentrates by Gas Chromatography2 •

D 3700 Practice for Containing Hydrocarbon Fluid Sam ples Using a Floating Piston Cylinder3

3. Summary of Practice

3.1 A liquid sample is transferred from the source into a

sample container by purging the container and filling it with liquid, then providing 20 % outage so that 80 % ofthe liquid volume remains.

4. SignHicance and Use

4.1 Samples of liquefied petroleum gases are examined by

various test methods to determine physical and chemical characteristics. The test results are often used for custody transfer and pricing determination. It is therefore essential that the samples be representative ofthe product to be tested.

I This practice is under the joint jurisdiction or ASTM Committee 0.2 on Petroleum and Petroleum Products and is the direct responsibility or Subcom mittee D02.H on Uqucfied Petroleum Gas.

Cumnt edition approved March 15, 1992. Published May 1992. Originally published as D 1265 - S3 T. Last previous edition D 126S - 87.

.:I Annual Book ofASTM Standards, VoIOS.OI.

3 Annual Book ofASTM Standards, Vois OS.02.

5. Genera1IDformation

5.1 Considerable effort is required to obtain a representa

tive sample, especially if the material being sampled is a mixture of liquefied petroleum gases. The following factors must be considered:

S.1.1 Obtain samples of the liquid phase only.

5.1.2 When it is definitely known that the material being

sampled is composed predominantly of only one liquefied petroleum gas, a liquid sample may be taken from any part of the vessel.

5.1.3 When the material being sampled has been agitated

until uniformity is assured, a liquid sample may be taken from any part of the vessel.

5.1.4 Because ofwide variation in the construction details

of containers for liquefied petroleum gases, it is difficult to specify a uniform method for obtaining representative sam ples of heterogeneous mixtures. If it is not practicable to agitate a mixture for homogeneity, obtain liquid samples by a procedure which has been agreed upon by the contracting parties.

S.1.S Directions for sampling cannot be made explicit enough to cover all cases. They must be supplemented by judgment, skill, and sampling experience. Extreme care and • good judgment are necessary to ensure samples which represent the general character and average condition of the material. Because of the hazards involved, liquefied petro leum gases should be sampled by. or under the supervision of, persons familiar with the necessary safety precautions.

NOTE 2-5amples to be tested for presence ofcorrosive compounds or sulfur compounds should be taken in stainless steel containers equipped with stainless steel valves; otherwise, determinations of mercaptans and hydrogen sulfide, for example, can be misleading.

5.1.6 Hydrocarbon vapors vented during sampling must

be controlled to assure compliance with applicable safety and environmental regulations.

6. Appar:atus

6.1 Sample Container-Use metal sample containers of a

type that ensures maximum safety and are resistant to corrosion by the product being sampled. A suitable material is stainless steel. The size ofthe container depends upon the amount of sample required for the laboratory tests to be made. The sample container should be fitted with an internal outage (ullage) tube to permit release of 20 % of the container capacity. The end of the container fitted with the outage (ullage) tube shall be clearly marked. Typical sample containers are shown in Figs. I and 2. Ifthe container is to be transported, it must often conform to specifications pub lished in TaritTNo. 10, "I.C.C. Regulations for Transporta tion ofExplosives and Other Dangerous Articles," its supple ments, or reissues. • http:VoIOS.OI

4t D 1265

CONTROl.

VALVE A

TO l'1l0DUC'l' SOURCE SAMPLlNO VALVEINJ..:Er

VALVE C

VI!NT

VALVP. B

FIG. 1 Typical Sample Container and Sampling CoMectlonS lLll"Or-- VALVE C

VALVE D

FIG. 2 Typical Sample Container and Alternate Purging Connections

41 01265

6.2 Sample Transfer Line made of stainless steel tubing or

other flexible metal hose, impervious to the product being sampled, is required. The most satisfactory line is one equipped with two valves on the sample-container end, Fig.

I, a control valve, A, and a vent valve, B.

PROCEDURE

D. Close outlet valve D and release the remainder of the sample in the liquid phase by opening vent valve B. Repeat the purging operation at least three times.

9. Transfer of Sample •9.1 Position the sample container securely in an upright position with outlet valve D at the top (Fig, I) and both

7. Purging Sample Transfer Line

7.1 Connect the ends of the transfer line securely to the

product source and to the inlet valve C of the container.

Qose the control valve A, vent valve B, and inlet valve C, Fig. 1. Open the valve at the product source and purge the transfer line by opening the control valve A and the vent valve B.

8. Purging the Sample Container

8.1 If the history of the sample container contents is not

known or if traces of the previous product could affect the analysis to be carried out, or both, use the following purge procedure:

8.1.1 Connect valve D of the sample container to the

sample transfer line with the container in an upright position and valve C at the top (Fig. 2).

8.1.2 Qose valves B, C, and D. Open valve A and then

valves C and D. Fill sample container until liquid issues from valve C. Qose valves C and D, then valve A on the sampling line.

8.1.3 Loosen the connection joining the sample container

to the sample line and tum container through 180· such that valve D is at the top. Open valves C and D and drain out liquid.

8.1.4 Return the sample container to position valve C at

the top. Tighten connection to sample transfer line and repeat the purging operation at least three times.

8.2 If the history of the sample container contents is

known, use the following purge procedure:

8.2.1 With the container in an upright position, Fig. I, and its outlet valve D at the top, close vent valve B and inlet valve C and open control valve A. Open inlet valve C-and partly fill the container with sample by slowly opening the outlet valve D. Qose the control valve A and allow part of the sample to escape in the vapor phase through outlet valve valves C and D closed.

9.1.1 Qose vent valve B, open the control valve A, open

inlet valve C, and fill container with the sample. Qose inlet valve C and the valve at the product source. Open vent valve B. After the pressure is fully reduced, disconnect sample container from the transfer line. Discard the sample ifa leak develops or if either valve is opened during subsequent handling of the sample container before performing the outage (ullage) operations outlined in section 10.

10. Sample Outage (Ullage)

10.1 Immediately after obtaining the sample, place the

container in an upright positioin with the outage (ullage) tube at the top.

10.1.1 Open outlet valve D slightly. Allow excess liquid to

escape and close the valve at the first sign of vapor. If no liquid escapes, discard the sample and refill the container.

11 Checking for Leaks , 11.1 After eliminating the excess liquid so that only 80 % of the sample remains, immerse in a water bath and check for leaks. Ifa leak is detected at any time during the sampling operation, disc~d the sample. Repair or replace the leaky container before obtaining another sample.

12. Care of Samples •12.1 Place samples in a cool location as soon as possible.

Keep them there until all tests have been completed. Discard any samples in containers which develop leaks. Protect the valves on the sample container, either by packing the container in a crate in an approved manner or by using a protective cap, so that accidental unseating of the valve or tampering with it is avoided

13 Keywords

13.1 liqumed petroleum gases; LPG; sampling

The American SocIety lor Testing and Msterlels takes no position respecting the validity 01 any patent rights asserted In connection with any /tam mentioned In thIs standard. Users 01 this standard are expressly advised that determination of the validity of any $Uch patent rights, and the risk of Infringement of such rights, are entirely their own responsibility.

This standard Is subject to revision at any time by the responsIble technical committee and must be reviewed every f{va years and If not revised, either reapproved or withdrawn. Your comments are Invited either lor revision 01 this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee. Which you may attend. If you fee} thet your comments have not received a fair hearing you should make your views known to the ASTM Committee on StandBlds. 1916 Race St, PhIladelphia, PA 19103.

4m~ Designation: D 1267 - 95 An American National Standard

• Standard Test Method for Gage Vapor Pressure of Liquefied Petroleum (LP) Gases (LP..Gas Method) 1

This standald is issued under the: fixed designation D 1267; the number immediately following the designation indicates the year of original adoption or, in the: case ofrevision, the year of last revision. A number in parentheses indicates the: year of last reapprovaL A supc:rsc:ript epsilon (.) indicates an editorial change since the last revision or reapproval.

1. Scope

1.1 This test method covers the determination of the gage

vapor pressures of liquefied petroleum gas products at temperatures of 37.8°C (lOO°F) up to and including a test temperature of 70·C (158°F).

1.2 This standard does not purport to address all of the

safety concerns, if any, associated with its use. It is the responsibility ofthe user ofthis standard to establish appro priate safety and health practices and determine the applica bility of regulatory limitations prior to use. For specific hazard statements, see Note 2 and Annex A2.

1.3 The values stated in acceptable metric units are to be

regarded as the standard. The values in parentheses are for information only.

2. Referenced Documents

• 2.1 ASTM Standards:

D323 Test Method for Vapor Pressure of Petroleum

Products (Reid Method)2 D 1265 Practice for Sampling Liquefied Petroleum (LP)

Gases (Manual Method)2 E I Specification for ASTM Thermometers3

2.2 Institute qfPetroleum Standard:

IP 181 Sampling Petroleum Gases"

3. Terminology

3.1 Definition:

3.1.1 vapor pressure-the pressure exerted by the vapor of a liquid when in equilibrium with the liquid

3.2 Description ofTerm Specific to This Standard:

3.2.1 liquefied petroleum gases-narrow boiling range hydrocarbon mixtures consisting chiefly of propane or propylene, or both, (Warning-see Note 1) butanes and butylenes, or both, in which the content of hydrocarbon compounds of higher boiling point than O~C (32~ is less than 5 % by liquid volume, and whose gage vapor pressure at 37.8~C (lOO"F) is not greater than approximately 1550 kPa (225 psi).

NOTE 1: Warning-Extremely flammable. Harmful when inhaled.

I This test method is under the jurisdic1ion of ASTM Committee D·2 on

Petroleum Products and Lubricants and is the direct responsibility of Subcom· mittee D02.H on Liquefied Petroleum Gas..

CUrrent edition approved April IS. 1995. Published June 1995. Originally published as D 1267 - 53 T. Last previous edition 0 1267 - 89.

aAnnual Book ofASTM Standards. Vol 05.Ql.

3 Annual Book ofASTM Standards, Vol 14.03.

4 Available from Applied Science Publishers. Ripple: Rd.• Barking. F.5Selt.

England

4. Summary of Test Method

4.1 The test apparatus, consisting of two interconnected

chambers and equipped with a suitable pressure gage, is purged with a portion of the sample which is then discarded.

The apparatus is then filled completely with the portion of the sample to be tested Thirty-three and one-third to forty volume percent of the sample content of the apparatus is immediately withdrawn to provide adequate free space for product expansion. The apparatus is then immersed in a water bath maintained at the standard test temperature of 37.8~C (lOO°F) or, optionally, at some higher test tempera ture up to and including a test temperature of 70°C (158"F).

4.2 The observed gage pressure at equilibrium, after

correcting for gage error and correcting to a standard barometric pressure, is reported as the LPG Vapor Pressure at the selected test temperature.

5. Significance and Use

5.1 Information on the vapor pressures of liquefied petro

leum gas products under temperature conditions from 37.8 to 70°C (l00 to 158°F) is pertinent to selection of properly designed storage vessels, shipping containers, and customer utilization equipment to ensure safe handling of these products.

5.2 Determination of the vapor pressure of liquefied

petroleum gas is important for safety reasons to ensure that the maximum operating design pressures of storage, han dling, and fuel systems will not be exceeded under normal operating temperature conditions.

5.3 For liquefied petroleum gases, vapor pressure is an

indirect measure of the most extreme low temperature conditions under which initial vaporization can be expected to occur. It can be considered a semi-quantitative measure of the amount of the most volatile material present in the product.

6. Apparatus

6.1 Vapor Pressure Apparatus, constructed as illustrated

in Fig. Al.1, and the various items of auxiliary equipment, are completely described in Annex AI.

6.2 The air chamber of Test Method D 323, may be

interchangeable with the upper chamber of this method Similarly, the liquid chamber (two-opening type) of Test Method D 323 is interchangeable with the B, 20 % lower chamber Annex Al.l.4 of this method. Because of this interchangeability, the apparatus assembly of Test Method D 323 must pass, as a safety precaution, the hydrostatic test specified in A1.1.6 before using same in testing liquefied petroleum gas.

4t 01267

7. Sampling and Sample Handling

7.1 Samples shall be obtained and stored in accordance

with Practice D 1265, or IP 181, Sampling Petroleum Gases, unless the test samples can be taken directly from the source of the material to be tested.

9.3.2 When using the 20 % lower chamber (Appendix

Al.l.4), close the straight-through valve and again open the inlet to permit expUlsion of the lower chamber contents. As soon as no more liquid escapes from the lower chamber, • close the inlet valve and immediately open the straight

7.2 Any method of coupling the vapor pressure apparatus

to the sample source can be employed. Tubing, 6 to 7 mm (1/4 in.) in diameter, of minimum length, of suitable-working pressure, and made of material corrosion-resistant to the products being sampled, is satisfactory for this purpose. A flexible tubing connection of a satisfactory type greatly facilitates the purging and sampling operations. The tubing should be a conducting material or constructed with a built-in ground connection to minimize the effect of static electricity.

8. Preparation of Apparatus

8.1 If the apparatus has been used for testing products

other than the type of product to be tested, disassemble, clean thoroughly, and purge the parts in a stream of dry air.

8.2 Assemble the apparatus with the inlet valve of the

lower chamber open, the straight-through valve between the two chambers open, the bleeder valve closed, and with the proper range pressure gage attached.

9. Procedure

9.1 Safe means for the disposal of vapors and liquids

during this operation and in the subsequent sampling operation must be provided.

9.2 Purging-With the assembled apparatus in an upright

position, connect the inlet valve of the lower chamber to the sample source with the sampling connection (7.2). Open the sample source valve to the apparatus. Cautiously open the bleeder valve on the upper chamber, permitting the air or vapors, or both, in the apparatus to escape until the apparatus is full of liquid. Close the lower chamber inlet valve and open the bleeder va1ve to its wide 'open position.

Allow the contained liquid to evaporate until the apparatus is covered with white frost (may require more than one chilling), then invert the assembly, and expel any residua1 material through the bleeder valve. Allow the residual vapors to escape until the pressure in the apparatus is essentia1ly atmospheric, then close the bleeder va1ve.

9.3 Sampling-Return the apparatus, now containing

only vapors, to its normal upright position and open the inlet valve. As soon as the apparatus attains essentially the same pressure as the pressure of the sample source, momentarily open the bleeder va1ve. If liquid does not promptly emerge, repeat the purging step (9.2). If liquid appears immediately, close the bleeder and inlet valves in that order (Note 2).

Close the valve on the sample source, and disconnect the sampling line. Immediately close the straight-through valve between the two chambers and open the inlet valve, with the apparatus in an upright position. Oose the inlet valve as soon as no more liquid escapes, and immediately open the straight-through va1ve (Note I).

NOTE 2-Transfer of the sample is facilitated by chilling the appa ratus with a portion of the material under test.

9.3.1 When using the 331/3 % lower chamber (A1.1.3)

through valve.

9.3.3 The upper chamber, prior to this operation, is liquid

full at some temperature that is normally below the environ mental temperature. Since any warming of the apparatus would cause expansion of the liquid content of the upper chamber, leading to possible rupture of the chamber, it is necessary that the procedural steps of providing free space in the apparatus be completed promptly.

9.4 Vapor Pressure Determination:

9.4.1 Invert the apparatus and shake it vigorously. Return

the apparatus to its norma1 upright position and immerse it in the constant-temperature water bath maintained at the test temperature (4.1). The apparatus including the bleeder valve coupling, but not the pressure gage, must be immersed.

Throughout the determination, the temperature of the water bath shall be checked periodically by means of the bath thermometer.

9.4.1.1 At test temperatures of SO°C (122°F) or below, maintain the bath at ±O.loC (0.2°F). At test temperatures above SO°C (1 22°F), up to and including 70°C (lS8°F), maintain the bath at ±0.3°C (OSF).

9.4.1.2 Observe the apparatus assembly throughout the

test period to ensure freedom from leaks. Discontinue the test and discard the results at any time a leak is detected.

9.4.2 After 5 min have elapsed, withdraw the apparatus

from the water bath, invert it, shake it vigorously, and then return it to the bath. Perform the shaking operation quickly • to avoid excessive cooling of the apparatus and its contents.

Thereafter, at interva1s of not less than 2 min, withdraw the apparatus from the bath, invert, shake it vigorously, and then return it to the bath. Prior to each remova1 of the apparatus from the water bath, tap the gage lightly and observe the pressure reading. These operations will normally require 20 to 30 min to ensure equilibrium. After this time, if consecu tive observed gage readings are constant, record the pressure reading as the Uncorrected LP-Gas Vapor Pressure of the sample at the test temperature.

9.4.3 Without removing the pressure gage from the appa

ratus or the apparatus from the bath, attach a test gage, previously calibrated against a dead-weight tester, to the bleeder valve outlet and open the bleeder valve. At the end of S min compare the readings of the two gages. Record any correction thus determined as gage correction.

10. Calculation

10.1 Correct the Uncorrected LP-Gas Vapor Pressure for

gage errors.

10.2 Convert the corrected vapor pressure = (test gage

reading) + (gage correction) as ca1culated in 9.4.3 to a standard barometric pressure of 760 mm (29.92 in.) Hg by means of the following equation:

10.2.1 LP-gas vapor pressure

= corrected vapor pressure, kPa - (760 - PI) 0.1333 (I) = corrected vapor pressure, psi - (760 - PI) 0.0193 (2) • proceed to 9.4. where:

4~ D 1267

PI = observed barometric pressure, mm Hg.

10.2.2 LP-gas vapor pressure

= corrected vapor pressure, kPa - (29.92 - P,) 3.3864 (3) "" corrected vapor pressure, psi - (29.92 - P2) 0.4912 (4) where:

P2 = observed barometric pressure, in. Hg.

10.2.3 Conversion Factors:

1 kPa "" 7.50064 mmHg = 0.295301 in. Hg I psi =51.7151 mmHg = 2.03603 in. Hg

11. Report

(5)

(6) (7)

11.1 Report the LP..Qas vapor pressure test results in

terms of kilopascals to the nearest 5 kPa or pounds per square inch, gage, to the half unit, and the test temperature.

12. Precision aud Bias

12.1 The following shall be used as a basis for judging the

acceptability of results (95 % probability).

12.1.1 Repeatability-The difference between two test re

suIts, obtained by the same operator with the same apparatus

• AI.I Vapor Pressure Apparatus, consisting of two cham bers, designated as the upper and lower chambers, shall conform to the following requirements. To maintain the correct volume ratio between the upper and lower chambers, the units shall not be interchanged without recalibrating to ascertain that the volume ratio is within satisfactory limits.

AI.I.1 Upper Chamber-This chamber, as shown in Fig.

A1.I (c), shall be a cylindrical vessel 51 ± 3 mm (2 ± 1/8 in.)

in diameter and 254 ± 3 mm (10 ± 1/8 in.) in len~, inside dimensions, with the inner surfaces of the ends slightly sloped to provide complete drainage from either end when held in a vertical position. On one end of the chamber, a suitable bleeder~valve coupling (Fig. AU (e» shall be provided to receive the bleeder-valve assembly and the pressure gage. In the other end of the chamber an opening approximately 13 mm (1/2 in.) in diameter shall be provided for coupling with the lower chamber. Care shall be taken that the connections to the end openings do not prevent the chamber from draining completely.

AI.l.2 Bleeder-Valve Assembly-The bleeder-valve for purging the apparatus (Fig. Al.1) (d» shall be a normal 6 mm (114 in.) valve fitted into the side of the bleeder-valve coupling (Fig. Al.l (e». The lower end shall be threaded to fit into the end fitting of the upper chamber, and the upper end shall be threaded to receive the gage coupling (Fig. Al.1 under constant operating conditions on identical test mate rials would in the normal and correct operation of the test method, exceed the following value only in one case in twenty:

12 !cPa (1.8 psi)

12.1.2 Reproducibility-The difference between two

single and independent results obtained by different opera tors working in different laboratories on identical test mate rial would in the long run, in the normal and correct operation ofthe test method, exceed the following value only in one case in twenty:

19 !cPa (2.8 psi)

12.2 Bias-The procedure in Test Method D 1267 for

measuring vapor pressure has no bias because the value of vapor pressure is defined only in terms of this test method.

13. Keywords

13.1 natural gas liquids; liquified petroleum gases; vapor pressure

ANNEXES

(Mandatory Information)

At. APPARATUS FOR VAPOR PRESSURE OF LIQUEFIED PETROLEUM (LP) GASES

AL1.4 Lower Chamber, 20 % (Fig. AJ.J (b»-Tbis chamber shall be a cylindrical vessel of such a volume that the ratio of the volume of the upper chamber to the volume of the lower chamber is between the limits of 3.95 to 4.05 (Note Al.2) (Note Al.3), In one end of the lower chamber, an opening approximately 19 mm W4 in.) in diameter shall be provided to receive a suitable straight~through valve (Fig.

Al.1 (g» having a minimum internal channel of 13 mm (1h in.) in diameter. The other end of the chamber shall be equipped with a nominal 6 mm (1/4 in.) inlet valve.

NOTE AI.I-In determining the volumetric capacities of the cham bers, the volume of the lower chamber is considered as that which is below the "straight-through" valve closure. The volume above the "straight-through" valve closure, including the portion of the coupling attached to the upper chamber, is considered as a part of the upper chamber volume. The volume ratios ofthe chambers are determined in accordance with the procedure outlined in the Appendix ofTest Method 0323.

NOTE Al .3-The apparatus requirements for this method, excluding the bleeder-valve assembly, are identical with those of Test Method o 323 with the exception of the 331/3 % lower chamber. Although the test procedural details are different, the air and liquid chambers of Test Method 0 323 may be used in the present method provided they are of sufficient strength to withstand the higher test pressures (Al.l.6).

A1.1.5 Method of Coupling Upper and Lower Cham bers-Any method of coupting the chambers can be em· ployed provided the volumetric requirements are met and

(h».

Al.1.3 Lower Chamber, jjllJ % (Fig. AI.J (b»-Tbis chamber shall be a cylindrical vessel of such a volume that the ratio of the volume of the upper chamber to the volume of the lower chamber is between the limits of 1.97 to 2.03 (Note A1.2).

that the assembly is free from leaks under the conditions of the test.

Al.1.6 Hydrostatic Test-The assembled chambers shall be certified by the manufacturer to withstand approximately 6920 !cPa (1000 psi) gage hydrostatic pressure without permanent deformation.

4~ D 1267

A (GAGEl •

G {STRAIGHT- THROUGH VAL.VEI

H (GAGE COUPL.ING!

D (BL.EEDE~ \~

VAL.VE I~ I .'\

E ~e(LOWERI BLEEDER , '. ._, CHAMBER I VALVE t .', •

COUPL.ING!

F (INL.ET VAL.Ve; I

C (UPPER CHAIooIBER I

FIG. A 1.1 Typical LPG Vapor Pressure Apparatus

Al.l.7 Checking for Freedomjrom Leaks-Before plac ing new apparatus in service, and as often as necessary there after, the assembled vapor pressure apparatus shall be checked for freedom from leaks by filling it with air, natural gas" nitrogen, or other similar gases, to 3460 kPa (500 psi) gage pressure, and then completely immersing it in a water bath. Only apparatus that will stand this test without leaking shall be used.

A 1.2 Pressure Gage-The pressure gage, shown in Fig.

A1.l (a), shall be a Bourdon-type spring gage of tes~ gage quality 114 to 140 mm (41/2 to 51h, in.) in diameter provided with a nominal 6 mm (1/4 in.) male thread connection with a passageway not less than 5 mm (3116 in.) in diameter from the Bourdon tube to the atmosphere. The range and graduations of the pressure gage used shall be governed by the vapor pressure of the sample being tested, as follows:

Gage to Be Used

LP-Gas Vapor Pressure, Scale Numbered Intermediate kPa (psi) gage at test temperature

655 (95) and under

620 (90) to 1750 (250)

J660 (240) to 3460 (500)

Range, Intervals, Graduations, kPa(psi) kPa (psi) kPa (psi) oto 700 (100)

70 (10) 3.4 (0.5) oto 1750 172 (25) 7 (l) (250) oto 3500 344 (50) 35 (5) (500)

Only accurate gages shall be continued in use. When the gage correction exceeds 2 % of the scale range, the gage shall be considered inaccurate. • A1.3 Vapor Pressure Bath-The vapor pressure bath

(water) shall be of such dimensions that the vapor pressure apparatus may be immersed so as to completely cover the bleeder valve when the assembly is in an upright position.

Means for maintaining the bath at the test temperature (2.1) within the range as follows: (1) Test temperature 50"C (122"F) and below, ±O.1"C (O.2"F); (2) Test temperature above 50"C (l22"F), ±O.3"C (0.5"F). In order to check the bath temperatures, the appropriate bath thermometer shall be immersed to the test temperature mark on the thermom eter scale throughout the vapor pressure determination.

AI.4 Thermometers-Only thermometers conforming to specifications in Specification E 1 or IP Standard Thermom eter Specifications shall be used. The range shall be governed by the test temperature of the test being used as follows:

Test Temperature Thermom Thermometer "C eterNo. Range"C

35 to 40 18C 34 to 42 50 to 80 65C 50 to 80

OF OF

95 to 105 18F 94 to 108

125 to 175 65F 122 to 176

AlA.! At other test temperatures a total immersion thermometer shall be used having a range that brackets the test temperature and a maximum scale error of0.1 "C (O.2°F).

A1.5 Dead-Weight Tester-A dead-weight tester of satis factory range shall be provided as a means for checking the accuracy of vapor pressure gages. •

4t D 1267

• A2. PRECAUTIONARY STATEMENT

A2.1 Propane/Butane, or Mixture of Both A2.1.5 Avoid buildup of vapors and eliminate all sources of ignition, especially nonexplosion-proof electrical appaA2.1.1 Vapors can cause flash fires.

ratus and heaters. A2.1.2 Keep away from heat, sparks, and open flame.

A2.1.6 A void prolonged breathing of vapor or spray mist. A2.1.3 Keep container closed.

A2.1.7 Avoid prolonged or repeated skin contact. A2.1.4 Use with adequate ventilation.

The American Society for Testing and Materials takes no position respecting the validity of 8II'f patent rights essetted In connection with any Item mentioned in this standard. Users of this standard are expressly advised that determination of the vaOdlty of any such patent rights, and the risk of Infringement of such rights, are entirely their own responslbHlty.

This standard Is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are Invited either for revision ofthis standard or for additional standards and should be addressed to ASTM Headquarters. Your comments wRl receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received B faIr hearing you should·make your views known to the ASTM CommIttee on Standards, 1916 Race St.• Phfladelphla. PA 19103.

~m~ Designation: D 1657 - 89 An American National Standard

Standard Test Method for Density or Relative Density of Light Hydrocarbons by Pressure Thermohydrometer1

This standard is issued under the fixed designation 0 1657; the number immediately following the designation indicates the year of original adoption or, in the case ofrevision, the year oflast revision. A number in parentheses indicates the year oflast reapproval. A superscript epsilon (f) indicates an editorial change since the last revision or reapproval.

1. Scope .

P This test method covers the determination of the relative density or density of light hydrocarbons including liquefied petroleum gases (LPG).

1.2 The prescribed apparatus should not be used for

materials having vapor pressures higher than 1.4 MPa (14 bar) at the test temperature. (The SI unit of pressure is the pascal: 1 Pa = 1 N/m2; lOS Pa = 1 bar = 1.01972 kgf/cm2.)

NOTE I-Attention is drawn to the hazards encountered when working with liquefied petroleum gas or light hydrocarbons. The requirements of any national, local, or domestic safety code should always be strictly observed.

1.3 The values in SI units are to be regarded as the

standard. The values in parentheses are for information only.

1.4 This standard may involve hazardous materials, oper

ations, and equipment. This standard does not purport to address all ofthe safety problems associated with its use. It is the responsibility Q[ the user of this standard to establish appropriate safety and health practices and determine the applicability ofregulatory limitations prior to use.

2. Referenced Docwnents

2.1 ASTM Standards:

D 1250 Guide for Petroleum Measurement Tables (ASTM l250/API 2540/IP 200)2 E 100 Specification for ASTM Hydrometers3

3. Terminology

3.1 Definitions:

3.1.1 density-the mass ofthe liquid per unit volume at a temperature t.

3.1.2 relative density (this term now replaces the former term "specific gravity")-the ratio of the mass of a given volume of the liquid at a temperature t1 to the mass of an equal volume of pure water at a temperature t2•

NOTE 2-When reporting the density, the units ofmass and volume used, together with the temperature, should be explicitly stated; for example, kg/m3 at t·C. The standard reference temperatures are lS·C and 6O"F.

When reporting the relative density, the temperatures tl and t2 should be explicitly stated; for example, relative density 60/60"F. The standard

! This test method .is under the jurisdiction of ASTM Comminee 0-2 011

Petroleum Products and Lubricants and is the direct responsibility of Subcom mittee OOZ.OZ.OC on Density.

Current edition approved March 31, 1989. Published May 1989. OriginaUy published as 0 1657 - 39 T. Last previous edition 0 1657 - 83 (1988)'1.

2 Annual Book ofASTM Standards, Vol. 05.01.

3 Annual Book ofASTM Standanls, Vol 14.03.

reference temperatures in general use are IS"C and 6O"F for both I. and t,.. but other temperatures may be employed for I ••

4. Summary of Test Method

4.1 The apparatus is purged with a portion of the sample

before filling with the portion to be used for testing. The pressure cylinder is filled to a level at which the enclosed hydrometer floats freely. The hydrometer reading and the temperature of the sample are noted.

S. Signifieance and Use

5.1 The density or relative density of light hydrocarbons

and liquefied petroleum gases is determined to satisfy transportation, storage, and regulatory requirements. Al though this determination does not describe any particular performance characteristic, density or relative density can be used to indicate approximate component concentrations in liquefied petroleum mixtures.

6. Apparatus4

6.1 Thermohydrometers, made of glass, graduated in den •sity with a range from 500 to 650 kgfm3, or in relative density with a wide range from 0.500 to 0.650, and con forming to the dimensions given in Table 1.

6.2 Hydrometer Cylinder, constructed of glass or trans

parent plastic; for example. poly(methyl methacrylate) or equivalent material, conforming to the design and dimen sions given in Fig. 1. The ends shall be tightly sealed with neoprene gaskets and metal end plates as shown in FIg. 1.

6.2.1 Caution-A protective shield shall be placed around

the plastic or glass cylinder. Replace any cylinders that show signs of fogging. crazing, cracking, or etching.

NOTE 3-Certain compounds attack plastics and cloud the inner surface of the cylinder, making it difficult or impoSSl"bie to read the hydrometer. Tests showed no attack by ethane, ethylene, propane, propylene, butane, isobutane, normal butylenes, isobutylene, pentane, and isopentane, and no attack is expected from butadiene and acetaldehyde. Users are cautioned, however. to clean the cylinder thoroughly after each determination.

Ketones and alcohols should not be used for cleaning as they attack and weaken plastics while aromatics also tend to attack the surfilce of plastics and should similarly not be used..

6.2.2 The liquid inlet valve and the liquid outlet valve

shall be tightly connected to a base plate that shall be bored to give both valves a common inlet to the cylinder. The

• Appa:alu$ suitable for this test may be obtained from: I!G&;G Chandler Engineering. 7707 I!. 38th SL, Tulsa, OK 74145; Peter Peterson Scientific Glassblowing, Inc., 473 Elmira Rd., Guelph, Ontario NIK 10; and Refinery Supply Co., Inc., 6901 E. 12th St., Tulsa, OK 74112. • http:OOZ.OZ.OC

Range, OF 30 to 90 Immersion tola!,Subdivisions. OF Intermediate Dnes at. OF 5 Main (numbered) lines at. OF 10 Scale error at eny point not to exceed. 0.5

Of Scale langth. mm 50 to 70

Thermohydrometer (Pressure)

ASTM Hydrom- Oenslty Range.

eter No. kgJni'

310H 500-650

Hydrometer

Nominal length. mm 387 Body diameter, mm 16 to 22 Nominal stem diameter, mm 10.5 Working pressure, kPa 1400

Hydrometer Scale

Standard temperature, °0 15 Subdivisions. kg/m3

Intermediate lines at. kg/m3

Main (numbered) Hnes at, kgfm3

Scale error at any point not to exceed, 1 kgfm3

Length of nominal scale, mm 125 to 145

Thermohydrometer

For Petroleum Products and Other Uquids of SimHar Surface Tensions

(33 dynes/em or less)

Thermometer Scale In Body

ASTM Hydrom- Nominal Relative eter No. Density Range

101H-62 0.500 to 0.650

Hydrometer

Totallenglll. mm 354 to 366 Body diameter, mm 19 to 22 Stem diameter min, mm 10.5 Working pressure min, psi 200

Hydrometer Scale

Standard temperature, OF 60/60 Subdivisions 0.001 Intermediate lines at 0.005 Main (numbered) Unes at 0.010 Scale error at eny point not to exceed 0.001 PLASTIC OR GLASS TUBe Lenglll at nominal scale, mm 125 to 145 51 mm OUTSleE OIAMeTER

65 mm WALLThermometer Scale

RuaBER

SEAL

LJ-HH- HYOROMETER

~~ 01657

TABLE 1

HII"HlH-l--- THeRMOMETER

LIQUIO

INl..ET VALVE'ITll;

RUBBeR SEAL

6.3 mrn (~ in., NEEDLE

VALVE LIQUID OUTLET

t 40...,,,, 1-----203",...,,----"'11-

FIG. 1 Pressure Thermohydrometer Cylinder

507.6 kgfm3 at 15°C or a relative density 60/60"F of0.50699.

7.1.2 n-Butane, pure grade. having a nominal density of

584.1 kg/m3 at 15°C or a relative density 60/60°F of0.5840.

vapor vent valve shall be similarly connected to the top plate, which shall be bored to provide a vapor outlet from the pressure cylinder. All valves shall be 6.3 mm (1/4 in.) or equivalent needle valves.

6.2.3 The cylinder shall not be operated at a gage pressure

greater than 1.4 MPa (14…