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Butane Residue Test Results
- Thread starter SkyHighLer
- Start date
"Obfuscation is the obscuring of intended meaning in communication, making the message confusing, willfully ambiguous, or harder to understand. It may be intentional or unintentional (although the former is usually connoted) and may result from circumlocution (yielding wordiness) or from use of jargon or even argot (yielding economy of words but excluding outsiders from the communicative value). Unintended obfuscation in expository writing is usually a natural trait of early drafts in the writing process, when the composition is not yet advanced, and it can be improved with critical thinking and revising, either by the writer or by another person with sufficient reading comprehension and editing skills.
The name comes from Latin obfuscatio, from obfuscāre ("to darken"). Obfustication is a common variant of the name, especially in British English. Synonyms include beclouding and abstrusity. Obscurantism is intentional obscurity, whether by withholding communication, obfuscating it, or both."
https://en.wikipedia.org/wiki/Obfuscation
Obfuscation,,,,, to post test results without indicating what test was used, and then draw conclusions about specifics which aren't mentioned in the test results.
Both Ecogreen and Best Value Vacs are offering Certificates of Analysis for their gases, but there's no indication that testing was done for non-volatile residue, a major issue from our point of view of 'clean gas.'
There are three standard tests for determining non-volatile residue (mystery oil) in LPG:
"ASTM D2158 - 11
Standard Test Method for Residues in Liquefied Petroleum (LP)"
https://www.astm.org/Standards/D2158.htm
(I employ a simplified, yet more accurate form of this boil off test.)
The second and third tests are relatively new, find a lab that'll perform one of them, post up the results, and I'll stfu.
"ASTM D7756 - 12
Standard Test Method for Residues in Liquefied Petroleum (LP) Gases by Gas Chromatography with Liquid, On-Column Injection"
http://www.astm.org/Standards/D7756.htm
"ASTM D7828 - 12
Standard Test Method for Determination of Residue Composition in Liquefied Petroleum Gas (LPG) Using Automated Thermal Desorption/Gas Chromatography (ATD/GC)"
https://www.astm.org/Standards/D7828.htm
The name comes from Latin obfuscatio, from obfuscāre ("to darken"). Obfustication is a common variant of the name, especially in British English. Synonyms include beclouding and abstrusity. Obscurantism is intentional obscurity, whether by withholding communication, obfuscating it, or both."
https://en.wikipedia.org/wiki/Obfuscation
Obfuscation,,,,, to post test results without indicating what test was used, and then draw conclusions about specifics which aren't mentioned in the test results.
Both Ecogreen and Best Value Vacs are offering Certificates of Analysis for their gases, but there's no indication that testing was done for non-volatile residue, a major issue from our point of view of 'clean gas.'
There are three standard tests for determining non-volatile residue (mystery oil) in LPG:
"ASTM D2158 - 11
Standard Test Method for Residues in Liquefied Petroleum (LP)"
https://www.astm.org/Standards/D2158.htm
(I employ a simplified, yet more accurate form of this boil off test.)
The second and third tests are relatively new, find a lab that'll perform one of them, post up the results, and I'll stfu.
"ASTM D7756 - 12
Standard Test Method for Residues in Liquefied Petroleum (LP) Gases by Gas Chromatography with Liquid, On-Column Injection"
http://www.astm.org/Standards/D7756.htm
"ASTM D7828 - 12
Standard Test Method for Determination of Residue Composition in Liquefied Petroleum Gas (LPG) Using Automated Thermal Desorption/Gas Chromatography (ATD/GC)"
https://www.astm.org/Standards/D7828.htm
Attachments
Last edited:
Great post, not really weed related, but I loved it anyway!
I purchased an online PDF of the ASTM D-2158 standard, it's been uploaded in it's entirety as an Attached File at the bottom of this post.
Designation: D2158 − 11
Test Method for
Residues in Liquefied Petroleum (LP) Gases
1. Scope*
1.1 This test method covers the determination of extraneous materials weathering above 38°C that are present in liquefied petroleum gases. The extraneous materials will generally be dissolved in the LPG, but may have phase-separated in some instances.
1.2 Liquefied petroleum gases that contain certain anti-icing additives can give erroneous results by this test method.
1.3 Although this test method has been used to verify cleanliness and lack of heavy contaminants in propane for many years, it might not be sensitive enough to protect some equipment from operational problems or increased maintenance. A more sensitive test, able to detect lower levels of dissolved contaminants, could be required for some applications.
1.4 WARNING—Mercury has been designated by many regulatory agencies as a hazardous material that can cause central nervous system, kidney and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to materials. Caution should be taken when handling mercury and mercury containing products. See the applicable product Material Safety Data Sheet (MSDS) for details and EPA’s website—http://www.epa.gov/mercury/faq.htm for additional information. Users should be aware that selling mercury and/or mercury containing products into your state or country may be prohibited by law.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:2
D96 Test Method for Water and Sediment in Crude Oil by Centrifuge Method (Field Procedure) (Withdrawn 2000)3
D1796 Test Method for Water and Sediment in Fuel Oils by the Centrifuge Method (Laboratory Procedure)
D1835 Specification for Liquefied Petroleum (LP) Gases
E1 Specification for ASTM Liquid-in-Glass Thermometers4
2.2 Energy Institute Document:
IP Test Methods - Appendix A. Specifications - IP standard thermometers
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 oil stain observation, n—the volume of solvent- residue mixture required to yield an oil stain or ring that persists for 2 minutes under specified conditions on absorbent paper.
3.1.2 residue, n—the volume, measured to the nearest 0.05 mL, of the residual material boiling above 38°C resulting from the evaporation of 100 mL of sample under the specified conditions of this test method.
3.1.3 solvent-residue mixture, n—a mixture (solution) of 10 mL of solvent with any residue remaining in the centrifuge tube at the conclusion of the first step in this test method.
4. Summary of Test Method
4.1 A 100-mL sample of liquefied petroleum gas is weathered in a 100-mL centrifuge tube. The volume of residue remaining after heating the tube to 38°C is measured and recorded.
4.2 To dissolve any residue, 10mL of solvent is added to the centrifuge tube. Small, measured volumes of solvent-residue mixture are deposited on an absorbent paper in a specified manner. The appearance of the absorbent paper to which the residue solution has been added in measured increments is observed and recorded.
5. Significance and Use
5.1 Control over the residue content (required by Specification D1835) is of considerable importance in end-use applications of LPG. In liquid feed systems residues can lead to troublesome deposits and, in vapor withdrawal systems, residues that are carried over can foul regulating equipment. Those that remain will accumulate, can be corrosive, and will contaminate following product. Water, particularly if alkaline, can cause failure of regulating equipment and corrosion of metals.
6. Interferences
6.1 Solid contaminants such as rust, scale or dirt can interfere with this test method, which is not intended for representative measurement of solid, undissolved contaminants.
7. Apparatus
7.1 Centrifuge Tube, 100-mL graduated, conforming to dimensions given in Fig. 1. The first 0.5 mL shall be graduated in 0.05-mL increments. The shape of the lower tip of the tube is especially important. The taper shall be uniform and the bottom shall be rounded as shown in Fig. 1. Tubes shall be made of thoroughly annealed heat-resistant glass. Volumetric graduation tolerances, based on air-free water at 20°C, are given in Table 1. Detailed requirements for centrifuge tubes appear in Test Methods D96 and D1796.
7.2 Cooling Coil and Cooling Bath, a minimum length of 6 m of 5 to 7-mm outside diameter copper tubing wound to a diameter of 63.5 6 1.5-mm outside diameter, and assembled in a suitable cooling bath. (See Fig. 2 as an example.)
7.2.1 Mechanical refrigeration is permitted provided that the coolant temperature is below −43°C. If dry ice is used, a non-glass dewar or vessel is recommended.
7.3 Syringe, 2-mL graduated in 0.1 mL and equipped with a needle 200 6 5 mm long. The needle may be either a sharp needle (ordinary medical syringe needle) or a safe, non-sharp syringe needle to avoid a puncture hazard. Alternatively, an equivalent liquid dispensing device capable of delivering 0.1-mL increments may be used, such as a 0.1-mL pipette.
7.4 Temperature Measuring Device, that is intrinsically safe, with accuracy equal to or better than Specification E1 or IP Test Methods - Appendix A shall be used. Thermometers conforming to Specification E1 or IP Appendix A have been found to be satisfactory.
Low Range –38°C to + 50°C IP 1C/ASTM 5C
or IP 2C/ASTM 6C
High Range –20°C to + 50°C ASTM 57C
NOTE 1—When a thermometer or a water bath, or both, are not available, for example when conducting a field test, a satisfactory alternative for screening purposes is to warm the tip of the centrifuge tube with the hand.
7.4.1 For routine testing, a general purpose thermometer with 0.5°C subdivisions and a maximum scale error of 0.5°C may be used.
7.5 Absorbent Paper, white, at least 100-mm diameter. Medium grade or rapid filter paper has been found to be satisfactory. In this test method, the paper will be referred to as “filter paper.”
7.6 Solvent Wash Bottle, typically polyethylene.
7.7 Water Bath, controlled at 38 6 2°C.
7.8 Copper Wire, 1 to 2-mm diameter, at least 10 mm longer than the centrifuge tube’s height.
7.9 Clamp, suitable for holding the centrifuge tube during weathering.
8. Reagents and Materials
8.1 Solvent—HPLC-grade pentane or cyclopentane. Another grade of solvent may be used provided that it meets the requirements of 10.2.
8.1.1 Although pentane is the preferred solvent for use in this test method, cyclopentane may be substituted for pentane whenever the ambient temperature or altitude is too high to enable the convenient handling of pentane.
8.1.2 Storage of solvent in a polyethylene wash bottle for several days contaminates the solvent. Therefore, do not use any solvent that has remained in a polyethylene wash bottle for more than one day.
9. Hazards
9.1 Note that there is a significant fire hazard from LPG vapors, and since the boiling point of LPG can be as low as −41°C, there is a risk of freezing “burns.” Take appropriate safety precautions to prevent ignition or fire, and wear suitable protective equipment to protect against skin contact with liquid or vaporizing LPG.
9.2 Operators should wear a grounded antistatic wrist strap. The use of an antistatic floor mat and grounding the sample cylinder are also advised.
10. Preparation of Apparatus
10.1 Wash all glassware that is to be used in the test in the selected solvent.
10.2 Verification of cleanliness of glassware and solvent
10.2.1 Add 10 mL of a new sample of solvent to the centrifuge tube.
10.2.2 Mark the center of the filter paper with a pencil or other non-pentane-soluble writing tool.
10.2.3 Fill the syringe or equivalent liquid dispensing device (see 7.3) with a portion of the solvent drawn from the centrifuge tube and direct 0.1-mL portions
of the solvent to the mark on the paper.
10.2.3.1 The solvent is added in 0.1-mL increments to confine the solvent ring to a circle about 30 to 35 mm in diameter. The filter paper should be held level during the solvent addition. One method is to place it on a 250-mL beaker.
10.2.4 Allow the solvent to evaporate for 2 min, and note the persistence of an oil ring.
10.2.4.1 The presence of an oil ring shall be observed by holding the dry filter paper between the eye and a bright incandescent light or strong daylight.
10.2.4.2 If no oil ring appears after 1.5 mL of solvent has been added, the solvent and glassware are satisfactory.
10.2.4.3 The appearance of an oil ring indicates either improperly cleaned glassware or contaminated solvent.
11. Procedure
11.1 Residue Measurement:
11.1.1 If the LPG sample is expected to be clean, with no residues or contaminants that could result in an oil stain, the procedure may be performed without a
cooling coil. However, if a residue or oil stain is detected using this screening procedure (that is, a residue is measured at greater than or equal to 0.05 mL in 11.1.7, or an oil stain is generated with 1.5 mL of test solution in 11.2.4), the test shall be repeated using a cooling coil.
11.1.2 Attach the cooling coil to the LPG sample source, cool the coil to below the boiling point of the sample, and flush the coil and sampling line.
11.1.3 Rinse and cool the centrifuge tube with the material to be sampled and then fill it to the 100-mL mark with a representative sample of LPG.
11.1.4 Immediately insert the copper wire through a clean, slotted cork or a clean, loose-fitting plug of cotton or cleansing tissue in the mouth of the centrifuge tube. The wire helps to prevent superheating and resulting bumping (erratic or excessive boiling), and the cork (or plug) will keep out air or moisture while the sample is weathering.
11.1.5 If more than 10 mL of the sample is lost because of bumping, obtain a new sample and repeat the test.
11.1.6 Allow the sample to weather, using artificial heating if the ambient temperature or type of sample requires it. If, when weathering has ceased and the tube has reached ambient temperature, a visible residue remains, place the tip of the tube in a water bath at 38°C for 5 min.
11.1.7 Record the volume of any remaining residue to the nearest 0.05 mL, and the presence of extraneous matter, if observed.
11.1.8 Perform the oil stain observation described in 11.2 even if there is no apparent or visible residue in the centrifuge tube. Experience has shown that there can be a thin film of oil on the inner surface of the centrifuge tube that is difficult to see and does not give a measurable volume, but can still give a ring or stain in the Oil Stain Observation procedure.
11.2 Oil Stain Observation:
11.2.1 Add sufficient solvent to the centrifuge tube containing the residue described in 11.1.6 to restore the volume to 10 mL. Add the solvent from the wash bottle and carefully wash down the sides of the tube. Stir well so that any residue at the bottom of the tube is dissolved uniformly in the solvent. Stirring with the syringe needle (see 7.3) or pipette has been found satisfactory. This mixture will be referred to as the solvent-residue mixture.
11.2.2 Mark the center of a clean white filter paper.
11.2.3 Fill the syringe or equivalent liquid dispensing device (see 7.3), and direct 1.5 mL of the solvent-residue mixture at the center of the paper at an appropriate rate such that the wetted circle is maintained at about 30 to 35 mm in diameter. If desired, steps 11.2.3 and 11.2.4 may be omitted, and the test continued according to 11.2.5.
11.2.4 After directing the entire 1.5 mL of residue solution onto the filter paper and at the end of a 2-min waiting period, if no oil ring persists when holding the dry filter paper between the eye and a bright incandescent light or strong daylight, discontinue the test and go to 12.1.
11.2.5 If a stain or ring is discernible, determine the volume of the solvent-residue mixture at which the oil stain or ring first persists for 2 min on a new filter paper by adding the solvent-residue mixture in 0.1-mL increments, waiting 2 min after each addition, and inspecting the paper for an oil stain at the end of the 2-min period.
11.2.6 Record the volume in millilitres of the solvent-residue mixture required to yield a persistent oil stain or ring as the oil stain observation.
11.2.7 Alternatively, if a product specification calls for adding a specified amount of solvent-residue mixture to the filter paper, add the specified quantity in 0.1 mL increments, and report the result at the specified total amount.
11.2.7.1 Specification D1835 specifies that 0.3 mL of solvent-residue mixture shall be deposited on the filter paper in 0.1-mL increments.
11.2.7.2 If there is no oil stain after the addition of 0.3 mL and a 2-min waiting period, report the result as “Pass.”
11.2.7.3 If an oil stain is observed at 0.3 mL after a 2-min waiting period, report the result as “Fail.”
11.3 Any solvent transferred to the wash bottle for purposes of running the test shall either be used in testing during the same day or discarded.
11.4 It has been noted that at low ambient temperatures (below about 5°C) materials in the gasoline boiling range will leave an oil stain or ring that persists after 2 min. Oil stain determinations should be made in a protected area where the temperature is above 5°C. If it is necessary to determine the oil stain at temperatures below 5°C, allow 10 min for oil stain persistence.
12. Report
12.1 Report the results as:
12.1.1 Residue on evaporation to the nearest 0.05 mL, and
12.1.2 Oil stain observation to the nearest 0.1 mL.
12.2 Alternatively, if the application of this test method calls for passing or failing the oil stain requirement at a specified volume of solvent-residue mixture, report the result at the specified volume as “Pass” or “Fail” (see 11.2.7).
13. Precision and Bias
13.1 Precision—Precision has not been determined on this method in terms of residue and oil stain results. Precision had been determined in terms of R and O numbers, as given in Appendix X1.
13.2 Bias—The procedure in this test method for measuring residues in LP Gas has no bias, because the residues are defined only in terms of this test method.
14. Keywords
14.1 contaminants; liquefied petroleum gases; LPG; oil stain; residue
http://www.astm.org/Standards/D2158.htm
Designation: D2158 − 11
Test Method for
Residues in Liquefied Petroleum (LP) Gases
1. Scope*
1.1 This test method covers the determination of extraneous materials weathering above 38°C that are present in liquefied petroleum gases. The extraneous materials will generally be dissolved in the LPG, but may have phase-separated in some instances.
1.2 Liquefied petroleum gases that contain certain anti-icing additives can give erroneous results by this test method.
1.3 Although this test method has been used to verify cleanliness and lack of heavy contaminants in propane for many years, it might not be sensitive enough to protect some equipment from operational problems or increased maintenance. A more sensitive test, able to detect lower levels of dissolved contaminants, could be required for some applications.
1.4 WARNING—Mercury has been designated by many regulatory agencies as a hazardous material that can cause central nervous system, kidney and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to materials. Caution should be taken when handling mercury and mercury containing products. See the applicable product Material Safety Data Sheet (MSDS) for details and EPA’s website—http://www.epa.gov/mercury/faq.htm for additional information. Users should be aware that selling mercury and/or mercury containing products into your state or country may be prohibited by law.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:2
D96 Test Method for Water and Sediment in Crude Oil by Centrifuge Method (Field Procedure) (Withdrawn 2000)3
D1796 Test Method for Water and Sediment in Fuel Oils by the Centrifuge Method (Laboratory Procedure)
D1835 Specification for Liquefied Petroleum (LP) Gases
E1 Specification for ASTM Liquid-in-Glass Thermometers4
2.2 Energy Institute Document:
IP Test Methods - Appendix A. Specifications - IP standard thermometers
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 oil stain observation, n—the volume of solvent- residue mixture required to yield an oil stain or ring that persists for 2 minutes under specified conditions on absorbent paper.
3.1.2 residue, n—the volume, measured to the nearest 0.05 mL, of the residual material boiling above 38°C resulting from the evaporation of 100 mL of sample under the specified conditions of this test method.
3.1.3 solvent-residue mixture, n—a mixture (solution) of 10 mL of solvent with any residue remaining in the centrifuge tube at the conclusion of the first step in this test method.
4. Summary of Test Method
4.1 A 100-mL sample of liquefied petroleum gas is weathered in a 100-mL centrifuge tube. The volume of residue remaining after heating the tube to 38°C is measured and recorded.
4.2 To dissolve any residue, 10mL of solvent is added to the centrifuge tube. Small, measured volumes of solvent-residue mixture are deposited on an absorbent paper in a specified manner. The appearance of the absorbent paper to which the residue solution has been added in measured increments is observed and recorded.
5. Significance and Use
5.1 Control over the residue content (required by Specification D1835) is of considerable importance in end-use applications of LPG. In liquid feed systems residues can lead to troublesome deposits and, in vapor withdrawal systems, residues that are carried over can foul regulating equipment. Those that remain will accumulate, can be corrosive, and will contaminate following product. Water, particularly if alkaline, can cause failure of regulating equipment and corrosion of metals.
6. Interferences
6.1 Solid contaminants such as rust, scale or dirt can interfere with this test method, which is not intended for representative measurement of solid, undissolved contaminants.
7. Apparatus
7.1 Centrifuge Tube, 100-mL graduated, conforming to dimensions given in Fig. 1. The first 0.5 mL shall be graduated in 0.05-mL increments. The shape of the lower tip of the tube is especially important. The taper shall be uniform and the bottom shall be rounded as shown in Fig. 1. Tubes shall be made of thoroughly annealed heat-resistant glass. Volumetric graduation tolerances, based on air-free water at 20°C, are given in Table 1. Detailed requirements for centrifuge tubes appear in Test Methods D96 and D1796.
7.2 Cooling Coil and Cooling Bath, a minimum length of 6 m of 5 to 7-mm outside diameter copper tubing wound to a diameter of 63.5 6 1.5-mm outside diameter, and assembled in a suitable cooling bath. (See Fig. 2 as an example.)
7.2.1 Mechanical refrigeration is permitted provided that the coolant temperature is below −43°C. If dry ice is used, a non-glass dewar or vessel is recommended.
7.3 Syringe, 2-mL graduated in 0.1 mL and equipped with a needle 200 6 5 mm long. The needle may be either a sharp needle (ordinary medical syringe needle) or a safe, non-sharp syringe needle to avoid a puncture hazard. Alternatively, an equivalent liquid dispensing device capable of delivering 0.1-mL increments may be used, such as a 0.1-mL pipette.
7.4 Temperature Measuring Device, that is intrinsically safe, with accuracy equal to or better than Specification E1 or IP Test Methods - Appendix A shall be used. Thermometers conforming to Specification E1 or IP Appendix A have been found to be satisfactory.
Low Range –38°C to + 50°C IP 1C/ASTM 5C
or IP 2C/ASTM 6C
High Range –20°C to + 50°C ASTM 57C
NOTE 1—When a thermometer or a water bath, or both, are not available, for example when conducting a field test, a satisfactory alternative for screening purposes is to warm the tip of the centrifuge tube with the hand.
7.4.1 For routine testing, a general purpose thermometer with 0.5°C subdivisions and a maximum scale error of 0.5°C may be used.
7.5 Absorbent Paper, white, at least 100-mm diameter. Medium grade or rapid filter paper has been found to be satisfactory. In this test method, the paper will be referred to as “filter paper.”
7.6 Solvent Wash Bottle, typically polyethylene.
7.7 Water Bath, controlled at 38 6 2°C.
7.8 Copper Wire, 1 to 2-mm diameter, at least 10 mm longer than the centrifuge tube’s height.
7.9 Clamp, suitable for holding the centrifuge tube during weathering.
8. Reagents and Materials
8.1 Solvent—HPLC-grade pentane or cyclopentane. Another grade of solvent may be used provided that it meets the requirements of 10.2.
8.1.1 Although pentane is the preferred solvent for use in this test method, cyclopentane may be substituted for pentane whenever the ambient temperature or altitude is too high to enable the convenient handling of pentane.
8.1.2 Storage of solvent in a polyethylene wash bottle for several days contaminates the solvent. Therefore, do not use any solvent that has remained in a polyethylene wash bottle for more than one day.
9. Hazards
9.1 Note that there is a significant fire hazard from LPG vapors, and since the boiling point of LPG can be as low as −41°C, there is a risk of freezing “burns.” Take appropriate safety precautions to prevent ignition or fire, and wear suitable protective equipment to protect against skin contact with liquid or vaporizing LPG.
9.2 Operators should wear a grounded antistatic wrist strap. The use of an antistatic floor mat and grounding the sample cylinder are also advised.
10. Preparation of Apparatus
10.1 Wash all glassware that is to be used in the test in the selected solvent.
10.2 Verification of cleanliness of glassware and solvent
10.2.1 Add 10 mL of a new sample of solvent to the centrifuge tube.
10.2.2 Mark the center of the filter paper with a pencil or other non-pentane-soluble writing tool.
10.2.3 Fill the syringe or equivalent liquid dispensing device (see 7.3) with a portion of the solvent drawn from the centrifuge tube and direct 0.1-mL portions
of the solvent to the mark on the paper.
10.2.3.1 The solvent is added in 0.1-mL increments to confine the solvent ring to a circle about 30 to 35 mm in diameter. The filter paper should be held level during the solvent addition. One method is to place it on a 250-mL beaker.
10.2.4 Allow the solvent to evaporate for 2 min, and note the persistence of an oil ring.
10.2.4.1 The presence of an oil ring shall be observed by holding the dry filter paper between the eye and a bright incandescent light or strong daylight.
10.2.4.2 If no oil ring appears after 1.5 mL of solvent has been added, the solvent and glassware are satisfactory.
10.2.4.3 The appearance of an oil ring indicates either improperly cleaned glassware or contaminated solvent.
11. Procedure
11.1 Residue Measurement:
11.1.1 If the LPG sample is expected to be clean, with no residues or contaminants that could result in an oil stain, the procedure may be performed without a
cooling coil. However, if a residue or oil stain is detected using this screening procedure (that is, a residue is measured at greater than or equal to 0.05 mL in 11.1.7, or an oil stain is generated with 1.5 mL of test solution in 11.2.4), the test shall be repeated using a cooling coil.
11.1.2 Attach the cooling coil to the LPG sample source, cool the coil to below the boiling point of the sample, and flush the coil and sampling line.
11.1.3 Rinse and cool the centrifuge tube with the material to be sampled and then fill it to the 100-mL mark with a representative sample of LPG.
11.1.4 Immediately insert the copper wire through a clean, slotted cork or a clean, loose-fitting plug of cotton or cleansing tissue in the mouth of the centrifuge tube. The wire helps to prevent superheating and resulting bumping (erratic or excessive boiling), and the cork (or plug) will keep out air or moisture while the sample is weathering.
11.1.5 If more than 10 mL of the sample is lost because of bumping, obtain a new sample and repeat the test.
11.1.6 Allow the sample to weather, using artificial heating if the ambient temperature or type of sample requires it. If, when weathering has ceased and the tube has reached ambient temperature, a visible residue remains, place the tip of the tube in a water bath at 38°C for 5 min.
11.1.7 Record the volume of any remaining residue to the nearest 0.05 mL, and the presence of extraneous matter, if observed.
11.1.8 Perform the oil stain observation described in 11.2 even if there is no apparent or visible residue in the centrifuge tube. Experience has shown that there can be a thin film of oil on the inner surface of the centrifuge tube that is difficult to see and does not give a measurable volume, but can still give a ring or stain in the Oil Stain Observation procedure.
11.2 Oil Stain Observation:
11.2.1 Add sufficient solvent to the centrifuge tube containing the residue described in 11.1.6 to restore the volume to 10 mL. Add the solvent from the wash bottle and carefully wash down the sides of the tube. Stir well so that any residue at the bottom of the tube is dissolved uniformly in the solvent. Stirring with the syringe needle (see 7.3) or pipette has been found satisfactory. This mixture will be referred to as the solvent-residue mixture.
11.2.2 Mark the center of a clean white filter paper.
11.2.3 Fill the syringe or equivalent liquid dispensing device (see 7.3), and direct 1.5 mL of the solvent-residue mixture at the center of the paper at an appropriate rate such that the wetted circle is maintained at about 30 to 35 mm in diameter. If desired, steps 11.2.3 and 11.2.4 may be omitted, and the test continued according to 11.2.5.
11.2.4 After directing the entire 1.5 mL of residue solution onto the filter paper and at the end of a 2-min waiting period, if no oil ring persists when holding the dry filter paper between the eye and a bright incandescent light or strong daylight, discontinue the test and go to 12.1.
11.2.5 If a stain or ring is discernible, determine the volume of the solvent-residue mixture at which the oil stain or ring first persists for 2 min on a new filter paper by adding the solvent-residue mixture in 0.1-mL increments, waiting 2 min after each addition, and inspecting the paper for an oil stain at the end of the 2-min period.
11.2.6 Record the volume in millilitres of the solvent-residue mixture required to yield a persistent oil stain or ring as the oil stain observation.
11.2.7 Alternatively, if a product specification calls for adding a specified amount of solvent-residue mixture to the filter paper, add the specified quantity in 0.1 mL increments, and report the result at the specified total amount.
11.2.7.1 Specification D1835 specifies that 0.3 mL of solvent-residue mixture shall be deposited on the filter paper in 0.1-mL increments.
11.2.7.2 If there is no oil stain after the addition of 0.3 mL and a 2-min waiting period, report the result as “Pass.”
11.2.7.3 If an oil stain is observed at 0.3 mL after a 2-min waiting period, report the result as “Fail.”
11.3 Any solvent transferred to the wash bottle for purposes of running the test shall either be used in testing during the same day or discarded.
11.4 It has been noted that at low ambient temperatures (below about 5°C) materials in the gasoline boiling range will leave an oil stain or ring that persists after 2 min. Oil stain determinations should be made in a protected area where the temperature is above 5°C. If it is necessary to determine the oil stain at temperatures below 5°C, allow 10 min for oil stain persistence.
12. Report
12.1 Report the results as:
12.1.1 Residue on evaporation to the nearest 0.05 mL, and
12.1.2 Oil stain observation to the nearest 0.1 mL.
12.2 Alternatively, if the application of this test method calls for passing or failing the oil stain requirement at a specified volume of solvent-residue mixture, report the result at the specified volume as “Pass” or “Fail” (see 11.2.7).
13. Precision and Bias
13.1 Precision—Precision has not been determined on this method in terms of residue and oil stain results. Precision had been determined in terms of R and O numbers, as given in Appendix X1.
13.2 Bias—The procedure in this test method for measuring residues in LP Gas has no bias, because the residues are defined only in terms of this test method.
14. Keywords
14.1 contaminants; liquefied petroleum gases; LPG; oil stain; residue
http://www.astm.org/Standards/D2158.htm
Attachments
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I also purchased online PDF's of the ASTM D-7756, and D-7828 standards, they've been uploaded in their entirety as Attached Files at the bottom of this post.
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Here's my basic non-volatile residue test:
Cut the top off a one gallon ziplock bag to further reduce the weight (generic bags are fine.)
Fold the bag up, place a rubber band around it, place it on a milligram scale, and record the tare weight.
Open the bag up wide, fold the top down one inch to stiffen it so it doesn't collapse, and place the bag into to an evaporating dish.
Place the evaporating dish in another dish like you would when doing an open blast boil off, warm water goes in the second dish...
Using a small scale, squirt about 165g (about a 300ml lighter refill can's worth) of solvent into a quart Mason jar. See the video, freezing the jar and solvent is of benefit in keeping the blow-by to a minimum.
Pour the solvent from the Mason jar into the bag.
Add warm water to the larger dish to speed up the boil off.
After boil off, pat dry the outside of the bag in case of condensation.
Vacuum down the bag to remove any volatile residue (like pentanes,) and moisture.
Fold the bag up, place the rubber band around it, place it on the milligram scale, and record the final weight.
The difference in weight is the amount of non-volatile residue ('mystery oil.')
Divide the weight of the non-volatile residue by the sample weight, and multiply the result by one hundred to obtain the percentage.
Notes:
Here's a video of how to squirt liquified gas into a Mason jar,
"New Method for making BHO" by Jamus Herbeau
https://youtu.be/VTVRYk0Zdg4?t=1s
Here's the milligram scale I use, and recommend,
http://www.amazon.com/American-Weig...d=1428083560&sr=8-1&keywords=milligrams+scale
Here's the 1,000g x 0.1g scale I use and recommend,
http://www.amazon.com/gp/product/B0012N1NAA?psc=1&redirect=true&ref_=oh_aui_detailpage_o05_s00
To get accurate milligram readings every reading must be followed by a check with the calibration weights. I recalibrate over and over as the scale's readings drift as it warms up. Feel free to obtain a better scale... but it's going to cost you dearly.
This test provides weight/percentage, odor, and tint of the non-volatile residue. Take a good whiff of the test bag before and after vacuuming down, there should be very little odor after vacuuming. Fold the residue area of the bag over a couple of times, and place on a white surface to check the tint. A little yellow tint is typical of Korean and Chinese gases even if it's good stuff otherwise.
https://www.icmag.com/ic/showpost.php?p=7229147&postcount=650
Cut the top off a one gallon ziplock bag to further reduce the weight (generic bags are fine.)
Fold the bag up, place a rubber band around it, place it on a milligram scale, and record the tare weight.
Open the bag up wide, fold the top down one inch to stiffen it so it doesn't collapse, and place the bag into to an evaporating dish.
Place the evaporating dish in another dish like you would when doing an open blast boil off, warm water goes in the second dish...
Using a small scale, squirt about 165g (about a 300ml lighter refill can's worth) of solvent into a quart Mason jar. See the video, freezing the jar and solvent is of benefit in keeping the blow-by to a minimum.
Pour the solvent from the Mason jar into the bag.
Add warm water to the larger dish to speed up the boil off.
After boil off, pat dry the outside of the bag in case of condensation.
Vacuum down the bag to remove any volatile residue (like pentanes,) and moisture.
Fold the bag up, place the rubber band around it, place it on the milligram scale, and record the final weight.
The difference in weight is the amount of non-volatile residue ('mystery oil.')
Divide the weight of the non-volatile residue by the sample weight, and multiply the result by one hundred to obtain the percentage.
Notes:
Here's a video of how to squirt liquified gas into a Mason jar,
"New Method for making BHO" by Jamus Herbeau
https://youtu.be/VTVRYk0Zdg4?t=1s
Here's the milligram scale I use, and recommend,
http://www.amazon.com/American-Weig...d=1428083560&sr=8-1&keywords=milligrams+scale
Here's the 1,000g x 0.1g scale I use and recommend,
http://www.amazon.com/gp/product/B0012N1NAA?psc=1&redirect=true&ref_=oh_aui_detailpage_o05_s00
To get accurate milligram readings every reading must be followed by a check with the calibration weights. I recalibrate over and over as the scale's readings drift as it warms up. Feel free to obtain a better scale... but it's going to cost you dearly.
This test provides weight/percentage, odor, and tint of the non-volatile residue. Take a good whiff of the test bag before and after vacuuming down, there should be very little odor after vacuuming. Fold the residue area of the bag over a couple of times, and place on a white surface to check the tint. A little yellow tint is typical of Korean and Chinese gases even if it's good stuff otherwise.
https://www.icmag.com/ic/showpost.php?p=7229147&postcount=650
^^ and ^^^
You guys aren't downloading the three ASTM LPG residual standards. Please do so. (cost me $150!)
(I know you're checking out the posts, the figures at the bottom of the long copy/paste post have high view counts)
Those are THE DOCUMENTS to bring up with when discussing non-volatile residue in your LPG.
Makes no matter the source of your gas, Praxair 99.99% research grade to refrigerant tanks from Asia, any NVR (non-volatile residue) claim is bs unless they can produce test results tracing back to one of the standardized procedures in those documents. I do, and did so in my last four posts.
All CoA's (Certificate of Analysis,) and third party after testing reports are useless for stating overall purity of LPG, unless they specifically state a NVR figure, and the ASTM standard used.
Look way up the petroleum chain to a CoA from a refiner, and you'll find an NVR entry along with the ASTM standard used to determine it, which is ASTM D2158, D7756, or D7828.
"Specifications of Imported Liquefied Petroleum Gas" JORDAN PETROLEUM REFINERY CO. LTD.,
http://www.jopetrol.com.jo/EchoBusV3.0/SystemAssets/fuelEN/L. P.G Specs.pdf
"Residues in L.P.G. - Max. 0.05 ml - ASTM D2158" I believe means pass/fail at more than 0.05 ml from the specified 100 ml LPG sample. 0.05ml/100ml = 0.0005 = .05%. Compare that to the worst I've found in my testing, about .01%. What we find offensive is a pass for them. (referencing the bottom of my list found via my ICMAG Signature link below, Spark 7X had 0.040g of residue per 300ml sample, 0.04/300 x 100 = .013%, assuming one ml is equal to one gram of greasy residue.) If you can understand this, and that their "Max. 0.05 ml" is the bottom line on the 100 ml centrifuge tube, you can see they can't get resolution below the 0.05 ml of residue per 100 ml of solvent point, something I achieve simply and concisely with my test.
I can't do this alone, brother John urges you to go forth with this and confront the obfuscating devils!
Must have been the Hash Church, you gotta' hear Indra go on about being doused in Napalm, and then relate about bathing in the ponds at Woodstock, blessed be.
You guys aren't downloading the three ASTM LPG residual standards. Please do so. (cost me $150!)
(I know you're checking out the posts, the figures at the bottom of the long copy/paste post have high view counts)
Those are THE DOCUMENTS to bring up with when discussing non-volatile residue in your LPG.
Makes no matter the source of your gas, Praxair 99.99% research grade to refrigerant tanks from Asia, any NVR (non-volatile residue) claim is bs unless they can produce test results tracing back to one of the standardized procedures in those documents. I do, and did so in my last four posts.
All CoA's (Certificate of Analysis,) and third party after testing reports are useless for stating overall purity of LPG, unless they specifically state a NVR figure, and the ASTM standard used.
Look way up the petroleum chain to a CoA from a refiner, and you'll find an NVR entry along with the ASTM standard used to determine it, which is ASTM D2158, D7756, or D7828.
"Specifications of Imported Liquefied Petroleum Gas" JORDAN PETROLEUM REFINERY CO. LTD.,
http://www.jopetrol.com.jo/EchoBusV3.0/SystemAssets/fuelEN/L. P.G Specs.pdf
"Residues in L.P.G. - Max. 0.05 ml - ASTM D2158" I believe means pass/fail at more than 0.05 ml from the specified 100 ml LPG sample. 0.05ml/100ml = 0.0005 = .05%. Compare that to the worst I've found in my testing, about .01%. What we find offensive is a pass for them. (referencing the bottom of my list found via my ICMAG Signature link below, Spark 7X had 0.040g of residue per 300ml sample, 0.04/300 x 100 = .013%, assuming one ml is equal to one gram of greasy residue.) If you can understand this, and that their "Max. 0.05 ml" is the bottom line on the 100 ml centrifuge tube, you can see they can't get resolution below the 0.05 ml of residue per 100 ml of solvent point, something I achieve simply and concisely with my test.
I can't do this alone, brother John urges you to go forth with this and confront the obfuscating devils!
Must have been the Hash Church, you gotta' hear Indra go on about being doused in Napalm, and then relate about bathing in the ponds at Woodstock, blessed be.
Attachments
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I spoke at length with the procurement agent Adam Marosi of Best Value Vacs gets his US gas from yesterday (note I'm not referring to the refrigerant grades R-600/R-290 BVV also carries.) I have a CoA posted up from this gas supplier that he provided Adam (see post #662.) The company Adam sources from in turn gets their gas from Gas Innovations, which we already know is Refined Hydrocarbon Solutions' source. Awesomely clean gas in my test of it!
I didn't even need ask in most instances, everything I've been suggesting was confirmed yesterday, and I received authoritative answers to every question I could think to ask, made my day....
The one thing I told him I'd be sharing publicly specifically relates to the non-volatile residue in LPG as reported in the CoA's in common distribution versus the refiner's full CoA's.
You may quote me on this, "Adam could have received the full spec CoA from the refiner for an extra $150, he declined. The full spec includes the non-volatile residue read." I'd give Adam the benefit of the doubt on this, he just didn't know why he needed it at the time.
That doesn't mean an exact non-volatile residue figure like I provide is available, just that a sample of gas was tested with the ASTM D2158 standard test, and it passed it's quantification degree of < .05 ml from a 100 ml sample.
I assume the head processing/QC engineer at the refinery has a little test like mine of his own to determine grades, but it isn't the crude ASTM D2158 test, and that's all they officially have to work with and report on unless they've upgraded to the newer tests, and I haven't found evidence of that. To the contrary, there's the above post's specs from the Jordan Petroleum Refinery Company, LTD stating from just two years ago they use ASTM D2158.
Whether your gas was repackaged in fresh, new, inspected tanks is another reason to do my test, swish the tank before taking the sample, and you'll likely see the rust if present.
http://gasinnovations.com/literature/LOW-PRESSURE-CYLINDER-PACKAGING-2.pdf
Bottom line, do my test on any and every lot of gas you acquire, even if it's coming from Praxair, Matheson, or Airgas. Gas Innovations in my test was clean, but who knows if they are consistent?
I didn't even need ask in most instances, everything I've been suggesting was confirmed yesterday, and I received authoritative answers to every question I could think to ask, made my day....
The one thing I told him I'd be sharing publicly specifically relates to the non-volatile residue in LPG as reported in the CoA's in common distribution versus the refiner's full CoA's.
You may quote me on this, "Adam could have received the full spec CoA from the refiner for an extra $150, he declined. The full spec includes the non-volatile residue read." I'd give Adam the benefit of the doubt on this, he just didn't know why he needed it at the time.
That doesn't mean an exact non-volatile residue figure like I provide is available, just that a sample of gas was tested with the ASTM D2158 standard test, and it passed it's quantification degree of < .05 ml from a 100 ml sample.
I assume the head processing/QC engineer at the refinery has a little test like mine of his own to determine grades, but it isn't the crude ASTM D2158 test, and that's all they officially have to work with and report on unless they've upgraded to the newer tests, and I haven't found evidence of that. To the contrary, there's the above post's specs from the Jordan Petroleum Refinery Company, LTD stating from just two years ago they use ASTM D2158.
Whether your gas was repackaged in fresh, new, inspected tanks is another reason to do my test, swish the tank before taking the sample, and you'll likely see the rust if present.
http://gasinnovations.com/literature/LOW-PRESSURE-CYLINDER-PACKAGING-2.pdf
Bottom line, do my test on any and every lot of gas you acquire, even if it's coming from Praxair, Matheson, or Airgas. Gas Innovations in my test was clean, but who knows if they are consistent?
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From Sean at Ecogreen, yesterday,
"Hi John,
Thank you for sharing the information regarding the ASTM non-volatile residue test with me! Per Graywolf's recommendation, we have all of our gas 3rd party tested by Specialty Analytical in Portland, Oregon. As far as I am aware, we are the only company that is providing 3rd party COA's from an independent lab. Our competitors are creating their own in-house COA's using Microsoft Word and expecting their customers to accept this information as legitimate. If I were their customer, I would ask them who actually performed the analysis which the COA is based upon.
The next time that we send our random samples up to Specialty Analytical for testing, I will inquire with Marty about running one of the three non-volatile residue tests that you are recommending. I think it's a good idea. We have really been working hard at improving our quality control and I am very proud to say that we have achieved 99.97% purity on all of our solvents, except for the n-butane which is still at 99.90%. If everything goes according to plan, we should also be seeing 99.97% for the n-butane sometime in January. Our customers are all very happy with the quality of our new gas. Everyone that has vacuum distilled our new gas says that there are zero condensables found in the collection pot after running the distillation run. The semi-volatile residues are synonymous with condensables. If you're interested in retesting any of our gas using your preferred method, just say the word.
Thank You"
This is the same response I get from every distributor, they won't even try my test.
"99.97% pure" --- so what, that would mean it could have as much crap as the nastiest canned butane I tested that had .024% of non-volatile residue (mystery oil.)
(Spark 7X had 0.040g of NVR, .04g/165g x 100 = .024%)
The ASTM D2158 NVR standard uses a 100ml/55g sample and provides no way to measure the amount of NVR lower than 0.05ml, or lower than .091%.
(.05g/55g x 100, ml/g = ~1 for oil, and a 300ml can of butane is equal to 165g, so 100ml = 55g)
With a NVR test threshold of .091% from any lab you'll find, no one can say if a specific lot of gas is any better in regards to NVR than Power 5X canned butane, unless they do a more sensitive test of their own.
For about $50 (two inexpensive scales and some gallon zip-lock bags,) and a vacuum chamber, and you can definitively test any solvent for NVR. It's two posts back, post #666
"Hi John,
Thank you for sharing the information regarding the ASTM non-volatile residue test with me! Per Graywolf's recommendation, we have all of our gas 3rd party tested by Specialty Analytical in Portland, Oregon. As far as I am aware, we are the only company that is providing 3rd party COA's from an independent lab. Our competitors are creating their own in-house COA's using Microsoft Word and expecting their customers to accept this information as legitimate. If I were their customer, I would ask them who actually performed the analysis which the COA is based upon.
The next time that we send our random samples up to Specialty Analytical for testing, I will inquire with Marty about running one of the three non-volatile residue tests that you are recommending. I think it's a good idea. We have really been working hard at improving our quality control and I am very proud to say that we have achieved 99.97% purity on all of our solvents, except for the n-butane which is still at 99.90%. If everything goes according to plan, we should also be seeing 99.97% for the n-butane sometime in January. Our customers are all very happy with the quality of our new gas. Everyone that has vacuum distilled our new gas says that there are zero condensables found in the collection pot after running the distillation run. The semi-volatile residues are synonymous with condensables. If you're interested in retesting any of our gas using your preferred method, just say the word.
Thank You"
This is the same response I get from every distributor, they won't even try my test.
"99.97% pure" --- so what, that would mean it could have as much crap as the nastiest canned butane I tested that had .024% of non-volatile residue (mystery oil.)
(Spark 7X had 0.040g of NVR, .04g/165g x 100 = .024%)
The ASTM D2158 NVR standard uses a 100ml/55g sample and provides no way to measure the amount of NVR lower than 0.05ml, or lower than .091%.
(.05g/55g x 100, ml/g = ~1 for oil, and a 300ml can of butane is equal to 165g, so 100ml = 55g)
With a NVR test threshold of .091% from any lab you'll find, no one can say if a specific lot of gas is any better in regards to NVR than Power 5X canned butane, unless they do a more sensitive test of their own.
For about $50 (two inexpensive scales and some gallon zip-lock bags,) and a vacuum chamber, and you can definitively test any solvent for NVR. It's two posts back, post #666
"The Benefits of Thermal Desorption Coupled with Gas Chromatography for the Analysis of Hydrocarbon Residues in Liquefied Petroleum Gas
Liquefied Petroleum Gas (LPG) is a hydrocarbon fuel produced from the refining of natural gas or the fractional distillation of crude oil. It is primarily a mixture of propane and butane that is used for a wide variety of field and industrial applications, including a fuel for motorised transport systems, a propellant for aerosols and as a gas for refrigeration purposes. Once produced, LPG is transferred to pipelines, ocean tankers or terminal delivery systems for long-distance distribution. Once at a distribution centre, LPG is typically transferred to a bulk truck or rail car for short-haul transport to a retail plant. From there, it is distributed in cylinders or bulk trucks for delivery to the retail customer. Figure 1 represents a simplified schematic of the LPG distribution Chain [1].
The transportation and delivery of LPG can lead to potential sources of contamination, which can be harmful to engines, motorised systems or industrial processes. For example, if gasoline or diesel fuel has been used in the transportation tankers, it can result in contamination of those components in the LPG. When compressors are used to pump the LPG into pressurised tanks, the oil can contaminate the LPG. And finally, phthalates and similar plasticisers can end up in the LPG from the delivery hoses used to fill pressurised cylinders.
ASTM International (ASTM) D1835 ‘Standard Specification for Liquefied Petroleum (LP) Gases’ [2] designates ASTM Method D2158 ‘Standard Test Method for Residues in Liquefied Petroleum (LP) Gases’ [3], as the referee method for residue measurement. However, residue contaminants in LPG using this evaporation/gravimetric procedure does not achieve the detection limits required by industry. Besides being time consuming and labour intensive, the sensitivity of the method is not sufficient for many of the more challenging applications of LPG including fuel cells and micro turbines, which require keeping the contaminants below 20 ppm (µg/g) for the process to work efficiently. In addition, Method D2158 can also produce inaccurate results, because low boiling point compounds are lost during the evaporation stage. In addition, the method does not generate any information about the source of the contaminating residue, which is useful for troubleshooting purposes.
This study will therefore describe a new method using Automated Thermal Desorption (ATD) coupled with gas chromatography (GC), for the measurement of residue in LPG down to 5µg/g, as well as yielding the hydrocarbon range of the contaminants, to give an understanding about the source of contamination. This methodology has since become a new ASTM Method D7828, ‘Standard Test Method for Determination of Residue Composition in Liquefied Petroleum Gas (LPG) Using Automated Thermal Desorption/Gas Chromatography (ATD/GC)’ [4].
Standard Test Method for Residues in Liquefied Petroleum Gases
ASTM D1835 states that besides the four main constituents of, methane, ethane, propane and butane, the residue contaminants, particularly longer chain hydrocarbons C6-C40, should be kept to an absolute minimum, because they can lead to problematic deposits in liquid feed and vapour withdrawal systems utilised in end-use applications of LPG. These residues also have the potential to be carried over and can foul up regulating equipment, and over time, the ones that remain can accumulate, and could contaminate additional components.
ASTM Method D2158 involves taking a 100-mL sample of liquefied petroleum gas, which is evaporated at 38°C in a customised centrifuge tube, cooled with a condensing coil and cooling bath. The volume of residue remaining is weighed, measured and recorded. This test method has been used to verify heavy contaminants in propane and LPG products for many years. However, in addition to being time-consuming, labour-intensive, and often dangerous with harmful vapours escaping into the atmosphere, the test has precision limitations. Therefore, besides not being sensitive enough to protect some equipment from operational problems or increased maintenance, it also cannot identify the source of residue.
In fact, D2158 states that if the LPG is specifically being used for certain applications such as micro turbines, a new electricity generation technology being designed for stationary energy applications, or fuel cells, which are used to convert hydrogen/hydrocarbon gases into electricity using proton exchange membrane (PEM) technology, a more sensitive test is required. It has been estimated that to use LPG for these kinds of applications, a residue detection capability of < 20 µg/g is required in order to ensure the efficiency and trouble-free operation of the technology."
https://www.chromatographytoday.com...bon_residues_in_liquefied_petroleum_gas/2000/
The referenced ASTM D1835 Standard Specification for Liquefied Petroleum (LP) Gases is available online,
https://www.scribd.com/document/258805910/ASTM-D1835
That's the spiel for one of the two new ASTM test standards I've been referencing, note they can get down to 5 μg/g with it, my test reads down to 6 μg/g with a 165g/300ml sample, double the sample size, and it reads down to 3 μg/g.
Liquefied Petroleum Gas (LPG) is a hydrocarbon fuel produced from the refining of natural gas or the fractional distillation of crude oil. It is primarily a mixture of propane and butane that is used for a wide variety of field and industrial applications, including a fuel for motorised transport systems, a propellant for aerosols and as a gas for refrigeration purposes. Once produced, LPG is transferred to pipelines, ocean tankers or terminal delivery systems for long-distance distribution. Once at a distribution centre, LPG is typically transferred to a bulk truck or rail car for short-haul transport to a retail plant. From there, it is distributed in cylinders or bulk trucks for delivery to the retail customer. Figure 1 represents a simplified schematic of the LPG distribution Chain [1].
The transportation and delivery of LPG can lead to potential sources of contamination, which can be harmful to engines, motorised systems or industrial processes. For example, if gasoline or diesel fuel has been used in the transportation tankers, it can result in contamination of those components in the LPG. When compressors are used to pump the LPG into pressurised tanks, the oil can contaminate the LPG. And finally, phthalates and similar plasticisers can end up in the LPG from the delivery hoses used to fill pressurised cylinders.
ASTM International (ASTM) D1835 ‘Standard Specification for Liquefied Petroleum (LP) Gases’ [2] designates ASTM Method D2158 ‘Standard Test Method for Residues in Liquefied Petroleum (LP) Gases’ [3], as the referee method for residue measurement. However, residue contaminants in LPG using this evaporation/gravimetric procedure does not achieve the detection limits required by industry. Besides being time consuming and labour intensive, the sensitivity of the method is not sufficient for many of the more challenging applications of LPG including fuel cells and micro turbines, which require keeping the contaminants below 20 ppm (µg/g) for the process to work efficiently. In addition, Method D2158 can also produce inaccurate results, because low boiling point compounds are lost during the evaporation stage. In addition, the method does not generate any information about the source of the contaminating residue, which is useful for troubleshooting purposes.
This study will therefore describe a new method using Automated Thermal Desorption (ATD) coupled with gas chromatography (GC), for the measurement of residue in LPG down to 5µg/g, as well as yielding the hydrocarbon range of the contaminants, to give an understanding about the source of contamination. This methodology has since become a new ASTM Method D7828, ‘Standard Test Method for Determination of Residue Composition in Liquefied Petroleum Gas (LPG) Using Automated Thermal Desorption/Gas Chromatography (ATD/GC)’ [4].
Standard Test Method for Residues in Liquefied Petroleum Gases
ASTM D1835 states that besides the four main constituents of, methane, ethane, propane and butane, the residue contaminants, particularly longer chain hydrocarbons C6-C40, should be kept to an absolute minimum, because they can lead to problematic deposits in liquid feed and vapour withdrawal systems utilised in end-use applications of LPG. These residues also have the potential to be carried over and can foul up regulating equipment, and over time, the ones that remain can accumulate, and could contaminate additional components.
ASTM Method D2158 involves taking a 100-mL sample of liquefied petroleum gas, which is evaporated at 38°C in a customised centrifuge tube, cooled with a condensing coil and cooling bath. The volume of residue remaining is weighed, measured and recorded. This test method has been used to verify heavy contaminants in propane and LPG products for many years. However, in addition to being time-consuming, labour-intensive, and often dangerous with harmful vapours escaping into the atmosphere, the test has precision limitations. Therefore, besides not being sensitive enough to protect some equipment from operational problems or increased maintenance, it also cannot identify the source of residue.
In fact, D2158 states that if the LPG is specifically being used for certain applications such as micro turbines, a new electricity generation technology being designed for stationary energy applications, or fuel cells, which are used to convert hydrogen/hydrocarbon gases into electricity using proton exchange membrane (PEM) technology, a more sensitive test is required. It has been estimated that to use LPG for these kinds of applications, a residue detection capability of < 20 µg/g is required in order to ensure the efficiency and trouble-free operation of the technology."
https://www.chromatographytoday.com...bon_residues_in_liquefied_petroleum_gas/2000/
The referenced ASTM D1835 Standard Specification for Liquefied Petroleum (LP) Gases is available online,
https://www.scribd.com/document/258805910/ASTM-D1835
That's the spiel for one of the two new ASTM test standards I've been referencing, note they can get down to 5 μg/g with it, my test reads down to 6 μg/g with a 165g/300ml sample, double the sample size, and it reads down to 3 μg/g.
Attachments
Last edited:
The apparatus that was used to test your LPG for non-volatile residue, please see the accompanying picture.
"RESIDUES IN LIQUEFIED PETROLEUM GASES
ASTM D2158 - IP 317
This test method covers the determination of the extraneous materials weathering above 38°C (100°F) which are present in liquefied petroleum gases. The LPG containing alcohols may cause error on results
CHARACTERISTICS
100 ml centrifuge tube
0,05 ml divisions on the 5 first ml
Anti corrosiveness coil
Dewar flask
SPECIFICATION
Tester for determination of the extraneous materials in LPG including Dewar flak, stand, cover with cooling coil, holder for weathering tube and ASTM 5C or 57C thermometer ( to specify when ordering)
REF. 941957
Apparatus for determining the extraneous residues above 100°F Complete with thermometer.
SPARE PARTS (2 years basis)
941297 8 inches cone-shaped tube (100 ml)
941942 Unsilvered Dew ar f lask
9911529 ASTM thermometer 57C
9911492 ASTM thermometer 5C"
http://www.mastrad.com/resi.htm
I've read it can take several hours to do the ASTM D2158 test, my test takes about an hour.
"RESIDUES IN LIQUEFIED PETROLEUM GASES
ASTM D2158 - IP 317
This test method covers the determination of the extraneous materials weathering above 38°C (100°F) which are present in liquefied petroleum gases. The LPG containing alcohols may cause error on results
CHARACTERISTICS
100 ml centrifuge tube
0,05 ml divisions on the 5 first ml
Anti corrosiveness coil
Dewar flask
SPECIFICATION
Tester for determination of the extraneous materials in LPG including Dewar flak, stand, cover with cooling coil, holder for weathering tube and ASTM 5C or 57C thermometer ( to specify when ordering)
REF. 941957
Apparatus for determining the extraneous residues above 100°F Complete with thermometer.
SPARE PARTS (2 years basis)
941297 8 inches cone-shaped tube (100 ml)
941942 Unsilvered Dew ar f lask
9911529 ASTM thermometer 57C
9911492 ASTM thermometer 5C"
http://www.mastrad.com/resi.htm
I've read it can take several hours to do the ASTM D2158 test, my test takes about an hour.
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"Adam Marosi <[email protected]> Nov 10 at 11:28 AM
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John,
I am Adam Marosi the owner of BestValueVacs. I wanted to reach out to you regarding the conversation you had with Joe from American Welding and Gas. Joe is our account rep and liaison between us and Gas Innovations. Refined Hydrocarbon as you may know is a competitior of ours and does use solvents from Gas Innovations. I understand you were inquiring about contaminants in our butane. I would like to tell you we are waiting on Worthington to relay to us how they clean their tanks prior to shipping. If you like I can forward that on to you. Our butane tanks are all stored inside prior to filling. They are all valved prior to receipt. Our process of filling includes a secondary purge after delivery followed by filling through a TRS21 or medical grade Nitrogen depending on how much time we have. This is fed through all stainless steel components. The only brass to hit the butane is on the propane tank and the bulk tank.
Regarding our import butane, we will be discontinuing it in the next 2 months. As far as I know we have the same supplier as Ecogreen however I would need to reconfirm it. When our techs run distillation on this butane or propane at 80f we see our butane leaves less residue by a significant margin than cans of Whip-it and Puretane to name a few. We are quite proud of the fact that we have dialed in our manufacturers to the current and the best source.
I am sorry for information overload, if you have any more questions we are happy to provide it to you and be as transparent as possible. There are many blogs out there that don’t even mention our solvents which is unfortunate. For selling anywhere from 15,000lbs/month to 35,000lbs/m in peak season with our quality products I wish there were more reviews. Any input is good input, it helps quality control. Thanks for the time, maybe we can speak in the future.
Regards,
Adam Marosi, President
BestValuevacs
Marosi Designs LLC
0: 331-281-0154
P: 630-445-8945
[email protected]"
To
[email protected]
CC
xxxxxxxxxxx, xxxxxxxxxxx, xxxxxxxxxxx
John,
I am Adam Marosi the owner of BestValueVacs. I wanted to reach out to you regarding the conversation you had with Joe from American Welding and Gas. Joe is our account rep and liaison between us and Gas Innovations. Refined Hydrocarbon as you may know is a competitior of ours and does use solvents from Gas Innovations. I understand you were inquiring about contaminants in our butane. I would like to tell you we are waiting on Worthington to relay to us how they clean their tanks prior to shipping. If you like I can forward that on to you. Our butane tanks are all stored inside prior to filling. They are all valved prior to receipt. Our process of filling includes a secondary purge after delivery followed by filling through a TRS21 or medical grade Nitrogen depending on how much time we have. This is fed through all stainless steel components. The only brass to hit the butane is on the propane tank and the bulk tank.
Regarding our import butane, we will be discontinuing it in the next 2 months. As far as I know we have the same supplier as Ecogreen however I would need to reconfirm it. When our techs run distillation on this butane or propane at 80f we see our butane leaves less residue by a significant margin than cans of Whip-it and Puretane to name a few. We are quite proud of the fact that we have dialed in our manufacturers to the current and the best source.
I am sorry for information overload, if you have any more questions we are happy to provide it to you and be as transparent as possible. There are many blogs out there that don’t even mention our solvents which is unfortunate. For selling anywhere from 15,000lbs/month to 35,000lbs/m in peak season with our quality products I wish there were more reviews. Any input is good input, it helps quality control. Thanks for the time, maybe we can speak in the future.
Regards,
Adam Marosi, President
BestValuevacs
Marosi Designs LLC
0: 331-281-0154
P: 630-445-8945
[email protected]"
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whats wrong with distilling at 80*?
Nothing is wrong with it...
Looks like the company intentionally recovers at low temp, to influence the test results...
Absolutely, but NO ONE recovers that low of temp....
Why not test at the temp the average user uses, right around 100F?
They didn't do a test. That would be like an auto mechanic pulling the dipstick, taking a glance at it at arm's length, declaring the crankcase ain't empty, and sticking it back in. No, you examine it up close to compare against the full level mark, take a look at the color, and notice if it smells burned.
ASTM 2158, the petroleum industry standard test for non-volatile residue cuts off at 100F/38C,
"4. Summary of Test Method
4.1 A 100-mL sample of liquefied petroleum gas is weathered in a 100-mL centrifuge tube. The volume of residue remaining after heating the tube to 38°C is measured and recorded."
https://www.icmag.com/ic/showpost.php?p=7682482&postcount=664
If they stopped distillation at 80F, they collected the semi-volatiles (pentane/iso-pentane/hexane/heptane, etc.,) along with the non-volatiles. I don't give a fuck about the semi-volatiles, they can be easily purged from product, and aren't especially toxic in comparison to the wickedly nasty non-volatiles.
What is so hard about the distributors like Ecogreen/RHS/BVV doing a simple check test on every bulk lot? My test is as scientific as ASTM 2158, is simpler, lowers the resolution floor to that of a GC analysis, and provides tint, and odor check.
Funny fact mentioned above: the petroleum industry's term for open boiling off LPG is "weathering." As in it's taking a weathering??
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And the other question Adam left dangling is, if his refrigerant grade gases are so clean, why are they discontinuing them?
What I've been told by two gas distributors sourcing from Gas Innovations, is the refrigerant grade isn't packaged properly, and the distributors will be shut down eventually by the Department of Transportation.
Probably just an established domestic supplier trying to keep inexpensive foreign imports out with cheap pot shots.
What I've been told by two gas distributors sourcing from Gas Innovations, is the refrigerant grade isn't packaged properly, and the distributors will be shut down eventually by the Department of Transportation.
Probably just an established domestic supplier trying to keep inexpensive foreign imports out with cheap pot shots.
You're welcome!
80F where? And bottom line, how much energy is necessary to keep it there??
What's the temp range of the usual butane solvent/oil solution as it boils off in an evaporating dish? You can add energy to make it boil off faster, but the inside of the dish and the solvent/oil temp range is about the same.
Here's some of the 'kitchen equipment' I use which validates my point that it's the total amount of energy input, not a temperature figure that expresses some meaningful information.
Notice the extension cord, boiling off of highly flammable solvents to free air should be done outside.
The silicone heater is stuck with the supplied 3M adhesive to the bottom of the Pyrex dish, and the energy inputed is controlled with a Variac. I adjust the Variac not to any temperature, but to the boiling off bubble action.
And that is how I think operators of CLS's should distill, by adjusting the energy input control in response to the bubbling action seen through the now all pervasive lid sight glasses. When you get near the bottom, cut the power way back, and while there's still a slosh in there, valve off, and vent the last of the LPG and semi-volatiles to the outdoors. You loose a little bit of butane, but you know you captured in one pass all the semi and non-volatiles.
Both Pyrex dishes are actual borosilicate Pyrex, one very old, one new, under the Arcuisine brand name from France. The US Pyrex you buy at the supermarket isn't boro, hasn't been for years, the new stuff can't take rapid, drastic temperature changes, plenty of info out there on the subject. I haven't gotten around to wiring and attaching the new dish's heater, I was kind of put off when I discovered the new dish is branded on the inside with a raised insignia, possibly a slight hassle when scaping. I also have the larger French import, and it has the same bump. I paid a lot for them at Amazon a couple of years ago, the price has dropped, much better, and I see Bed, Bath, and Beyond has them for cheap.
https://en.wikipedia.org/wiki/Pyrex
The last two pictures show a P4400 Kill A Watt meter connected to give you readings of how much energy you're delivering.
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