【国外标准】 Standard Test Method for Wax Appearance Temperature and Wax Disappearance Temperature of Petroleum Products and Liquid Fuels

5.1 The wax appearance temperature of petroleum products and liquid fuels is an indicator of the lowest temperature of their utility for certain applications. Wax crystals of sufficient quantity can plug filters or impede flow in some fuel systems.5.2 The wax disappearance temperature of petroleum products and liquid fuels is an indicator of the warmest temperature to remove thermal history. Wax crystals of sufficient quantity can plug filters or impede flow in some fuel systems.5.3 NIR light scattering technology is useful for recognition of wax crystal formation in dark and opaque fuels, and the cloud point in transparent fuels.5.4 The wax appearance temperature is an earlier indicator of wax crystal formation than pour point and has better resolution than pour point.5.5 This test method can determine the temperature of the test specimen at which wax crystals have formed sufficiently to be observed with a resolution of 0.1 °C.1.1 This test method covers the determination of the wax appearance temperature and the wax disappearance temperature of petroleum products and liquid fuels by an automatic instrument using optical light scattering detection.1.2 This test method is applicable to such materials as: crude oil, distillate fuels, residual fuels such as No. 6 Fuel Oil, marine fuels such as VLSFO, and including mixtures of these fuels and liquid biofuels.1.3 This test method covers the range of temperatures from –30 °C to +75 °C with temperature resolution of 0.1 °C.1.4 This test method contains interim precision with repeatability only; a full ILS will be completed within five years of its approval.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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.