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ERAVAP Crude Oil

Crude Oil Vapor Pressure Testing at its Best

ERAVAP Crude is the solution for crude oil vapor pressure testing. It is tuned for measuring live or dead crude according to ASTM D6377, IP481 and GOST 52340. It includes optimized CCQTA methods for low V/L ratios. Curve measurements cover a temperature range from -20 °C to 120 °C over a wide pressure range with excellent precision and measuring stability.


Correlation to

    ASTM D323
  • ASTM D1267
  • ASTM D2533
  • ASTM D2879
  • ASTM D4953
  • ASTM D5190
  • ASTM D5482

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Crude Oil Vapor Pressure Testing

Vapor pressure of crude oil is a key parameter when planning the transportation of crudes through different climate zones. When performing crude oil vapor pressure measurements one has to bear the actual ambient conditions during transportation in mind. Is the crude transported in rail cars the headspace is approximately 5% where as a floating roof-top tank has nearly no headspace at all. This is important since the vapor to liquid ratio (V/L) and the storage temperature are highly influencing the vapor pressure of crude. This is especially true for live crude oil which still contains high amounts of volatile light ends.

This graphs show the vapor pressure of crude oil for different temperatures and vapor to liquid ratios. Smaller V/L ratios and higher temperatures lead to higher vapor pressures.

V/L and Temperature Influences

The graph on the side shows the influence of the V/L ratio and the temperature on crude oil vapor pressure testing.

Measuring at the standard conditions of V/L = 4 and T = 37.8 °C the vapor pressure of the sample crude was approximately 40 kPa. At a V/L ratio of 0.02 found in rail cars, trucks or ships already gives a vapor pressure of around 100 kPa. Assuming that this storage tank stands in bright sunlight heating its content to a temperature of 60 °C the vapor pressure rises even further to 120 kPa.

The more light ends the transported crude contains the higher these effects will get. This highlights the importance to measure the crude’s vapor pressure under realistic conditions.

  • ERAVAP Manual Piston Cylinder
  • ERAVAP MPC Quick Fit Connectors

Crude Oil Configuration

Measuring live crudes containing high amounts of volatiles requires the use of a pressurized sampling system, such as floating piston cylinders (FPC) or manual piston cylinders (MPC). If such crudes are measured from an open bottle the resulting vapor pressure of this crude will be biased to the real vapor pressure since all volatiles will be lost. eralytics newly developed manual piston cylinder ERAVAP MPC (ASTM D8009) offers an even more comfortable and reliable application for this task. For an easy connection to the instrument, ERAVAP is equipped with a pressure-tight connection inlet for quick fit connectors including an integrated inlet filter. With its built-in high performance shaker motor ERAVAP measures in full compliance with ASTM D6377.

Crude Oil

High Viscosity Module

ERAVAP Crude directly draws up the sample into the measurement chamber by a piston. Sample take-up of more viscous samples naturally takes longer time until a viscosity where it becomes impractical. Heating up the sample prior to the introduction reduces the viscosity and the filling procedure speeds up. However, during the measurement, the sample sitting in the inlet and outlet tubing will cool down which possibly leads to a blockage of one of the tubes.
With the high viscosity module, the inlet, outlet, and all connecting tubes, as well as the inlet assembly, can be heated up to 70°C. This temperature is programmed from the measurement menu of the instrument and actively controls the temperature. This optional module makes ERAVAP the perfect analyzer for challenging samples such as fuel oil or heavy crudes without risking clogging of the equipment.

ERAVAP crude oil measuring curve

ASTM D6377 and CCQTA Recommendations

ASTM D6377 allows to use a wide range of different parameters for crude oil vapor pressure testing. Thus it can be tailored to fit the parameters for most conditions. Studies by the Canadian Crude Quality Technical Association (CCQTA), however, showed that the thermal expansion of the samples makes measurements at very low V/L ratios difficult. CCQTA prefers to analyze the V/L ratio curves at a specific temperature to judge the crude oil.

eralytics’ found a solution for the thermal expansion issue in ERAVAP crude and therefore can measure accurate crude oil vapor pressures at V/L = 0.02. Additionally, curve measurement programs at various V/L ratios are available, including the TVP method (True vapor pressure) which calculates the theoretical VPCR at V/L = 0. This makes ERAVAP crude the ideal choice for crude oil measurement applications.

In May 2013 the U.S. EPA approved ASTM D6377 for the measurement of the true vapor pressure of crude oil under title 40 CFR due to its broad applicability at different conditions.
Andreas Schwarzmann, eralytics' ASTM delegate

Technical Specifications

Available Test Methods
ASTM D5188, D5191, D6377, D6378, D6897, EN13016-1, EN13016-2, EN13016-3 ,IP394, IP409, IP481, JIS K2258-2, SHT 0769, SHT 0794, SNT 2932, GOST 52340
freely programmable methods
EPA / CARB / US Military & NATO reference methods, TVP measurement
VP-V/L Speed TestTM – Combined T(V/L) and vapor pressure measurement
Correlation to...
ASTM D323, D1267, D2533, D4953, D5190, D5482, D2879 (optional low vapor pressure extension)
Fuel Specifications
ASTM D910, D1655, D1835, D4814, D6227, EN 228
Temperature Range
0 °C to 120 °C (32 °F to 248 °F) with Peltier technology. No external cooling is required.
-20 °C to 120 °C (-4 °F to 248 °F) with additional low temperature upgrade (EV01-COOL). External cooling is required.
Extrapolated range: -100 to 300 °C (-148 °F to 572 °F)
Temperature Stability
0.01 °C (0.02 °F)
Pressure Range
0 kPa to 1 000 kPa (0 psi to 145 psi)
Pressure Resolution
0.01 kPa (0.0014 psi)
Vapor / Liquid Ratio
Variable from 0.02/1 to 100/1
Single-, multi-point and curve measurements
Repeatability: r ≤ 0.15 kPa (0.022 psi) / Cyclopentane @ 37.8°C
Reproducibility: R ≤ 0.50 kPa (0.073 psi)
Available Extension Modules
EV01-COOL: Low temperature module (-20°C - 120°C / -4°F - 248°F)
EV01-VISC: High viscosity module (Heated inlet and outlet up to 70°C / 158°F)
EV01-VPL: Low vapor pressure module (r = 0.1 kPa; pressure resolution = 0.01 kPa)
Auto Sampler
Optional 10-position auto sampler – directly attached

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