SH/T 0168-1992 Determination of colour of petroleum products

AI-translated method card — human verification pending. This is not an official translation of the standard. Unclear source values remain unverified; check the original standard and product certificate before use.

Card type: test method

1. Standard designation, title, English title and supersession

• Standard designation: SH/T 0168-1992 (confirmed in 2000 according to the source card).
• Title translated from Chinese: Determination of colour of petroleum products.
• Official English title: not found in the available source.
• Supersession: replaces ZB E30 009-88.
• First publication: 1980-12.
• Approval and implementation: approved by China Petrochemical Corporation on 1992-05-20; implemented on 1992-05-20.

2. Scope and exclusions

• Scope: this standard specifies a method for determining the colour of petroleum products, including lubricating oils, kerosene and diesel fuels.
• Exclusions: not found in the available source.

3. Principle

Place the sample in a colour-comparison tube and compare it with standard coloured glass filters. Report the matching colour number as the sample colour.

4. Reagents and materials: purity and preparation

• 4.2.1 Kerosene: for diluting dark oils; water-white and no darker than colour number 1 of this standard.
• 4.2.2 Lens-cleaning paper.
• Annex B: preparation of colour-comparison solutions for checking standard glass filters:
  • B1.1 Sulfuric acid (H₂SO₄) solution: slowly add 1 mL of analytical-reagent sulfuric acid of density 1.84 to 99 mL of distilled water. The available card does not specify the density unit.
  • B1.2 Hydrochloric acid (HCl) solution: slowly add 10 mL of analytical-reagent hydrochloric acid to 90 mL of distilled water.
  • B1.3 Potassium dichromate (K₂Cr₂O₇) solution, 1 g/L: dissolve 1 g of analytical-reagent potassium dichromate in sulfuric acid solution (B1.1) and dilute to 1000 mL. Each millilitre contains 1 mg of potassium dichromate.
  • B1.4 Cobalt sulfate (CoSO₄·7H₂O) solution, 500 g/L: dissolve 50 g of analytical-reagent cobalt sulfate in sulfuric acid solution (B1.1) and dilute to 100 mL.
  • B1.5 Ferric chloride (FeCl₃·6H₂O) solution, 500 g/L: dissolve 250 g of analytical-reagent ferric chloride in hydrochloric acid solution (B1.2), dilute to 500 mL, and filter before use.
  • B1.6 Ammonium thiocyanate (NH₄CNS) solution, 3 g/L: dissolve 0.3 g of solid ammonium thiocyanate in distilled water and dilute to 100 mL.
  • B2 Preparation of colour-comparison solutions: measure the solution volumes specified in Table B1 for each colour number. The extracted values in Table B1 are severely garbled and remain unverified; the available card does not provide a usable preparation table.
  • B3.1 Store colour-comparison solutions in the dark at 25°C±3°C. Their stated validity is one week.
  • B3.2 Prepare and use colour-comparison solutions at 25°C±3°C.
  • B3.3 Standard glass filters have a stated service validity of half a year; check them against the colour-comparison solutions when that period expires. If a filter differs from its corresponding solution by more than 1 colour number, adjust or replace it before use.

5. Apparatus

• 4.1.1 Colour comparator: comprises a light source, standard colour disc, prism and viewing eyepiece, with colour-comparison tubes (see Annex A). Before leaving the factory, the comparator should be adjusted so that the brightness of the two halves of the field is equal.
• 4.1.2 Colour-comparison tube: a flat-bottomed cylinder of clear, colourless glass, internal diameter 32.5–33.4 mm and height 120–130 mm (see Annex A).
• Annex A: technical requirements for the colour comparator:
  • A1 Light source: separate from, or integrated into, the comparator. The source card specifies an internally frosted lamp as 220 V, 100 V, with a colour temperature of 2750 K±50 K. The repeated voltage specification is unresolved; do not infer a wattage from it. Light passing through opal glass and a daylight filter should have spectral characteristics similar to north daylight. The two filtered parallel beams must have identical size and shape, illuminating the standard coloured glass and the sample uniformly before entering the eyepiece through prisms and mirrors. The daylight filter transmittance must be at least 0.6 at 410 nm, decreasing smoothly to below 0.10 at 700 nm. At 570 nm it must not exceed the line joining the transmittances at 540 nm and 590 nm by more than 0.03. The source wording also limits transmittance at 700 nm to no more than 0.03 above that at any shorter wavelength; verify this wording against the original before applying the criterion.
  • A2 Colour-comparison tube: a clear, colourless, flat-bottomed glass cylinder; internal diameter 32.5–33.4 mm, wall thickness 1.2–2.0 mm, overall height 120~130 mm.
  • A3 Standard colour disc: holds standard glass filters for 25 colour numbers and a blank aperture. The filter apertures and blank aperture must each be at least 14 mm in diameter; the disc must rotate. Filters are made from optical glass of different colours, formed into discs of diameter 14 mm and thicknesses of 1.0, 1.5 and 2.0 mm, combined and secured in the disc apertures. Stacked filters are permitted. Their colours must match the colour-comparison solutions prepared according to Annex B.
  • A4 Viewing eyepiece: permits simultaneous observation of the sample and standard glass in the same field. Each occupies an equal semicircular area, separated by a black vertical divider in the centre, 2~3 mm wide. The eyepiece must provide convenient light adjustment and focusing.

6. Recommended operating conditions

• Light source: internally frosted lamp specified as 220 V, 100 V, with a colour temperature of 2750 K±50 K (Annex A1). The repeated voltage specification in the card remains unresolved; no wattage has been inferred.
• Preparation and use temperature for colour-comparison solutions: 25°C±3°C (B3.2).
• Other operating conditions: not found in the available source.

7. Sampling and sample preparation

• 5.1 Carefully clean the colour-comparison tubes with lens-cleaning paper.
• 5.2 Fill one tube with distilled water to a depth exceeding 50 mm and place it on the right side of the covered compartment as the reference liquid.
• 5.3 Fill another tube with clear sample to a depth exceeding 50 mm, place it on the left side of the covered compartment and close the lid. If the sample is cloudy or opaque, heat until the cloudiness disappears, transfer it to the tube and measure immediately.
• 5.4 If the sample is darker than standard glass filter number 25, dilute with kerosene and determine the colour of the mixture. Use a sample-to-kerosene volume ratio of 15:85.

8. Procedure

• 6.1 Switch on the light and turn the standard colour-disc handwheel while observing through the eyepiece. When the sample matches a standard glass filter, record the displayed colour number. If it lies between adjacent filters, record the colour-number range, such as 11–12 or 15–16. For a sample measured after dilution with kerosene, state diluted in the report.
• 6.2 After measurement, switch off the light, remove the tubes and wash them for subsequent use.

9. Identification, quantification and calculations

• The colour number of the matching standard glass filter is the sample colour (Chapter 3 and 6.1).
• Calculation formula: not found in the available source.

10. Precision

• Repeatability: the difference between two repeated determinations by the same operator must not exceed 1 colour number.
• Reproducibility: not found in the available source.

11. Reporting

• Report the higher colour number from the repeated determinations.
• State diluted when the sample was measured after dilution with kerosene.

12. Referenced documents

• GB/T 6540: determination of the colour of petroleum products.
• Annex C: supplementary correspondence between this standard's colour numbers and GB/T 6540 colour numbers, described in the source as ISO colour numbers; see Figure C1. The extracted values in the correspondence chart are severely garbled and remain unverified.

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick reference