ASTM D6377 for determination of vapor pressure of crude oil
ASTM D6377 standard test method for determination of vapor pressure of crude oil: VPCR(X) (Expansion method)
1. Scope
1.1 This test method covers the use of automated vapor pressure instruments to determine the vapor pressure of crude oils at temperatures between 5 and 80°C for vapor-liquid ratios from 4:1 to 0.02:1 (X = 4 to 0.02) and pressures from 7 to 500 kPa (1.0 to 70 psi).
1.2 The values stated in SI units are regarded as standard. The inch-pound units given in parentheses are provided for information only.
1.3 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:
D323 Test Method for Vapor Pressure of Petroleum Products (REID Method)
D2892 Test Method for Distillation of Crude Petroleum (15-Theoretical Plate Column)
D3700 Practice for Obtaining LPG Samples Using a Floating Piston Cylinder
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D5191 Test Method for Vapor Pressure of Petroleum Products (Mini Method)
D5853 Test Method for Pour Point of Crude Oils
3. Terminology
3.1 Definitions of Terms Specific to This Standard: 3.1.1 dead crude oil - a term usually employed for crude oils that, when exposed to normal atmospheric pressure at room temperature, will not result in actual boiling of the sample.
3.1.1.1 Discussion - Sampling and handling of dead crude oils can usually be done without problems in normal sample containers, such as cans and so forth. The use of pressure cylinders for (sub)sampling and sample storage is a necessary and mandatory requirement in this test method for live crude oils and, to prevent the loss of volatile material and preserve precision, is strongly recommended for dead crude oils as well.
3.1.2 live crude oil - a term usually employed for crude oils contained in pressurized systems that, when brought to normal atmospheric pressure at room temperature, will result in actual boiling of the sample.
3.1.2.1 Discussion - Sampling and handling of samples of live crude oils will necessitate the use of pressure cylinders and preclude the use of normal sample containers, such as cans and so forth.
3.1.3 Reid vapor pressure equivalent (RVPE) - a value calculated by a correlation equation (see 14.3 and Appendix X1) from VPCR4, which is related to the value obtained on the sample by Test Method D323.
3.1.4 vapor-liquid ratio (V/L), n - the ratio of the vapor volume to the liquid specimen volume.
3.1.4.1 Discussion - The total measuring chamber volume is the sum of the vapor volume and the liquid specimen volume.
3.1.5 vapor pressure of crude oil (VPCRx), n - the pressure exerted in an evacuated chamber at a vapor-liquid ratio of X:1 by conditioned or unconditioned crude oil, which may contain gas, air or water, or a combination thereof, where X may vary from 4 to 0.02.
