ASTM D7679-16(R2020) pdf free download

ASTM D7679-16(R2020) pdf free download.Standard Test Method for Sulfur Content in Carbon Black Feedstock Oils
1. Scope
1.1 This test method covers the instrumental determination of sulfur content in samples of carbon black feedstock oils. Values obtained represent the total sulfur content. Two analysis methods are available for use:1.2 This test method is applicable to carbon black feedstock oils derived from petroleum, coal, and other sources which include fuel oils, residues, tars, pitches, reclaimed oils, and similar materials that are normally handled as liquids. This test method is applicable to products typically containing 0 to 5 mass % sulfur. 1.3 The results of these tests can be expressed as mass % sulfur. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 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 appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.6 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Summary of Test Method
4.1 In this test method, a sample of feedstock oil is weighed in a combustion boat containing either a tungsten oxide based accelerator, sand or aluminum oxide absorbent, and the sulfur content is determined by placing the boat in a tube furnace at 1350°C in an air or oxygen-enriched atmosphere resulting in complete combustion. Sulfur in the sample is completely oxidized to sulfur dioxide. Moisture and particulates are removed from the gas stream by traps filled with anhydrous magnesium perchlorate. The gas stream is then passed through a cell in which sulfur dioxide concentration is measured by an infrared (IR) absorption detector at a precise wavelength in the IR spectrum. The IR absorption detects sulfur dioxide through- out the entire combustion process. The integral of the detector signal is the basis for the total sulfur content of a sample. 4.2 This test method is for use with commercially available sulfur analyzers equipped to carry out the combustion and measurement operations automatically. 4.3 The sulfur analyzer shall be calibrated using appropriate calibration standards (see 6.7). 4.4 The instrument may be configured to analyze more than one element such as a carbon-sulfur analyzer. In this case, the analyzer has individual detectors for each element that are arranged in series.
5. Apparatus
5.1 There are a number of commercially available instru- ments designed to measure sulfur content in organic materials including sulfur and carbon-sulfur combustion analyzers. This test method makes no specifications regarding system designs. 5.2 Functionally, however, the following are specified for all instruments: 5.2.1 An analytical balance, or equivalent, that is capable of a weighing sensitivity of 0.1 mg or better resolution. 5.2.2 The combustion tube and boat are made of a suitable material such as mullite, porcelain, or zircon. 5.2.3 The sample is absorbed onto a solid which may include the following materials: (1) tungsten oxide based accelerator; (2) Sea sand; (3) Aluminum oxide. Refer to the instrument manufacturer’s recommendations. 5.2.4 The sample is combusted at a temperature of 1350 6 15°C in an air or oxygen-enriched atmosphere. 5.2.5 The combustion gas is passed through an absorbent (anhydrous magnesium perchlorate) to remove water vapor. 5.2.6 The detection system measures sulfur dioxide using an IR absorption detector at a wavelength suitable for linear responses with respect to the concentration over the full range of possible concentrations.