The newly engineered ERASPEC mid FTIR and NIR Analyzer (Figure 1) brings precise, automated, quick and comprehensive chemical analysis directly to your laboratory.

[Figure 1] ERASPEC mid FTIR and NIR.

Introducing the ERASPEC Mid-FTIR Analyzer, a cutting-edge chemical analysis device designed for rapid and precise measurement of various chemical properties. It features three cell sizes (20, 100, and 500 μm) to enhance result accuracy. This revolutionary analyzer, further enhanced with the NIR Upgrade Module, seamlessly integrates mid-FTIR and NIR spectroscopy, setting a new standard in the characterization and quality control of chemicals such as gasoline, diesel, and jet fuel formulations

Mid-FTIR and NIR: A Powerful Combination

The integration of mid-FTIR and NIR spectroscopy in the ERASPEC analyzer combines the
strengths of both techniques:

• Mid-FTIR: Offers in-depth analysis of the molecular structure and composition of chemicals. It is particularly effective for identifying and quantifying specific chemical bonds and functional groups.
• NIR: Provides rapid analysis, ideal for quantifying components and properties such as octane number, cetane number, and various physical parameters. Additionally, NIR can detect responses from compounds, such as alkanes, that are typically not as prominent in Mid-IR spectroscopy, thereby offering a broader scope of chemical analysis.

The ERASPEC analyzer with the NIR upgrade is a game-changer for chemical analysis, delivering multiple benefits:

• Comprehensive Analysis: Capable of analyzing gasoline, diesel, and jet fuels, ensuring broad applicability in fuel quality control and research.
• Accuracy and Speed: Combines the precise molecular analysis of mid-FTIR with the rapid assessment capabilities of NIR, offering unmatched accuracy and efficiency.
• Ease of Use: Designed for user-friendly operation, with minimal training required for accurate and repeatable results.
• Regulatory Compliance: Adheres to various ASTM standards, ensuring compliance with industry regulations and standards.

PLS MIR+NIR Fuel Prediction Model

The development and application of the Partial Least Squares (PLS), mid-FTIR (MIR) + near-Infrared (NIR) model for fuel prediction represent a significant advancement in fuel analysis technology. This report summarizes the key findings and implications of using the PLS MIR+NIR model. This model offers enhanced predictive capabilities compared to traditional Fourier-Transform Infrared (FTIR) and Multiple Linear Regression (MLR) models, particularly in addressing the variability in fuel composition due to changes in crude oil sources and distribution systems.

The ERASPEC analyzer has become a market leader due to its fast, easy-to-build libraries and reliable results. Traditional FTIR models, which were effective for localized fuel analysis, have struggled with the increasing complexity and number of variables in fuel compositions. This is due to the process of diverse crude oils and the widespread distribution of gasoline in refineries, which caused significant challenges in maintaining accurate and stable fuel models.

Model Performance

The PLS MIR+NIR model was developed using a comprehensive dataset of 715 samples collected across four regions of China, 15 European samples with ethanol. The model was further validated with 100 additional samples from China and 17 samples from Florida, USA.

[Figure 2] Models of Pentane and Decane.

Key Findings

1. Self-Prediction of the Model:
The PLS MIR+NIR model demonstrated superior accuracy compared to the MLR MIR model. The Standard Error of Calibration (SEC) was significantly lower for the PLS MIR+NIR model (0.37) compared to the MLR MIR model (0.78).

[Figure 3] Results of PLS and MLR models. It shows a superior accuracy of the PLS model.

2. Validation with Unknown Samples:
When tested on unknown samples similar to the model, both the PLS MIR+NIR and MLR MIR models performed well, but the PLS MIR+NIR model was approximately twice as accurate. The SEC for the PLS MIR+NIR model was 0.40, while it was 0.87 for the MLR MIR model.

[Figure 4] Results for the unknown samples for PLS and MLR models have the same trend.

The PLS MIR+NIR model’s ability to integrate new information from the NIR spectrum, particularly combination reports that provide additional information on CH2/CH3 distributions, has contributed to its enhanced stability and accuracy. This extended spectral range allows for better predictions for unknown fuels, and the model’s capacity to update directly on the instrument without external devices ensures its adaptability to new fuel compositions.

Real-World Impact

The ERASPEC analyzer’s dual spectroscopy approach significantly enhances the throughput and reliability of chemical testing in laboratories and industrial settings. It enables precise monitoring of fuel quality, helping to prevent engine and machinery damage, optimize performance, and ensure regulatory compliance. The integration of mid-FTIR and NIR spectroscopy in the ERASPEC analyzer opens up a wide range of applications across various industries, showcasing its versatility and advanced capabilities.

Refinery and Petrochemical Operations

It ensures precise fuel blending to meet specific quality standards and regulatory requirements.

Aviation Industry

It performs jet fuel analysis to ensure fuel quality meets the standards for safety and performance.

Environmental Monitoring

It analyzes fuel compositions to assess their environmental impact, and it helps industries to comply with environmental regulations by providing accurate data on fuel properties and emissions.

Renewable Fuels

It ensures the quality of biofuels such as ethanol and biodiesel.

Research and Development

It provides detailed analysis of experimental fuels under various conditions to evaluate their performance and potential applications.

Oil and Gas

It analyzes oil samples from exploration wells for reservoir characterization, and monitors production fluid to ensure the quality of produced oil meets required standards.

In summary, the ERASPEC mid FTIR Fuel Analyzer with the NIR Upgrade Module sets a new standard in fuel analysis, providing unmatched accuracy, efficiency, and versatility across a multitude of industries. The PLS MIR+NIR model is a significant improvement over traditional fuel prediction models, particularly in its ability to handle variability in fuel composition. Its enhanced accuracy, demonstrated by lower SEC values and better validation performance with unknown samples, makes it a valuable analysis tool for the modern fuel industry. Its advanced features and wide-ranging applications make it an essential tool for ensuring chemical quality, optimizing performance, and supporting regulatory compliance, thereby revolutionizing the field of chemical analysis.

Measuring the elemental content serves several critical purposes that are vital for ensuring the performance, reliability, and longevity of both the lubricants and fuels. Regularly checking the elemental content ensures that the lubricant maintains its specified composition, ensuring consistent performance. This is particularly important during manufacturing and before the lubricant is applied in critical machinery. Further reasons for conducting such measurements are the following:

• Detection of Wear Metals:
  As equipment components wear down during operation, metallic particles are generated and circulated throughout the lubrication system. Analyzing the elemental content helps in detecting wear metals that are released into the lubricant from machinery components. This can indicate the wear rate of parts, allowing for predictive maintenance and preventing catastrophic failures. In case of machinery failure, analyzing the elemental content of the lubricant can help identify the root cause.
• Contaminant Identification:
  The presence of certain elements can signify contamination from sources like dirt, coolant leaks, or sea water. Identifying these contaminants helps to understand error modes and narrow down the possible causes.
• Additive Depletion:
  Lubricants contain various additives that enhance performance by providing properties like anti-wear, anti-oxidation, and corrosion resistance. Measuring these elements helps in assessing the condition and remaining useful life of the lubricant. Professionals in the industry typically monitor potential changes in concentration over time, starting from the initial concentration of the fresh lubricant.

Table 1 summarizes the most important elements linked to their main origin.

Methods to perform elemental analysis

The history of elemental analysis goes back to the 1940s and 1950s when it was used in the railroad industry to determine the presence of wear metals in diesel engine oils.

In its present form, elemental analysis is used to determine the concentrations of more than 30 different elements.

Nearly all oil analysis labs utilise one of two types of atomic emission spectrometers: either an inductively coupled plasma (ICP) instrument or a rotating disc electrode (RDE) instrument. The primary difference between these two lies in the method of sample vaporisation and atom excitation by the high-energy source. In an ICP instrument, the oil is injected into a high-temperature argon plasma, where the atoms are vaporised, excited, and subsequently emit light. In an RDE spectrometer, also known as an “Arc-Spark” instrument, the oil is vaporised and excited using a high-voltage discharge between an electrode and a rotating carbon disc.

Besides the different vaporisation and excitation methods, the rest of the instrument functions similarly in both ICP and RDE spectrometers. The emitted light from the excited atoms is collected and focused onto the spectrometer’s slit. Inside the spectrometer, a diffraction grating, which functions like a prism, splits the light into discrete wavelengths based on their angle of diffraction.

The light intensity at each angle, typically referred to as a channel, is measured using a light-sensitive photodiode. The resulting voltage signal is then converted into a concentration in parts per million (ppm) through a calibration procedure. Although ICP and RDE measure the elemental composition of a sample using a common principle, the practical implementation of the two techniques is radically different.

An ICP requires sample preparation, typically including acid pre-treatment and microwave digestion, and a supply of carrier gas. As the measurement procedure is quite involved, ICPs are typically found in well-equipped labs with skilled operators. The RDE method, on the other hand, does not require any sample preparation and the sample is measured as received. The instrumentation requires stable temperature conditions, but otherwise no additional materials. This means that the RDE method can be used not only in an industrial environment, but also in the field or at remote locations.

The ICP method offers the advantage of sub-ppm detection limits as well as the ability to detect sulphur in routine analysis. The RDE instruments typically do not detect sulphur due to the lack of a vacuum system but offer ppm detection limits for up to 32 elements, including the relevant elements found as wear in oil additive packages. For used oil analysis, RDE offers the advantage that it can detect particles up to 10 μm, whereas ICP typically only detects particles below 5 μm.

Data comparison

To investigate the relation between the elemental composition determined by ICP and RDE, 35 samples of gear oil, hydraulic oils and motor oils were collected from a steel plant. Both fresh and in-service oils were used for the study. The samples were measured using a 2500 ICP-OES spectrometer from Agilent according to ASTM D5185 and an ERAOIL RDE-OES spectrometer according to ASTM 6595. For the ICP measurements, the samples were treated with nitric acid and hydrogen peroxide and then microwave digested at 190°C. The RDE samples were measured without sample preparation.

Elements that were detected by ICP in at least 20% of the samples were used for the comparison.

In general, the ICP and RDE results match well for both the detected wear metals as well as elements that can be assigned to additives. Figure 1 shows the correlation between iron (Fe) and zinc (Zn) levels in the samples. Table 2 summarizes the obtained correlations for all investigated elements.

All investigated elements showed a high degree of correlation between the two methods with R2 factors above 0.95 and correlation factors close to unity. The deviation of the correlation factor from 1 is probably not related to a difference in calibration, as both techniques are calibrated with similar certified reference materials. It is possible that the difference is related to the sample preparation used for ICP and the different ways the two methods excite the atoms in the sample. In this way, the difference only appears for actual samples and not for the artificial metallo-organic complexes used to calibrate the instruments.

For a sub-set of the collected samples, a clear difference in the results from the ICP and the RDE could be shown for one element. The collected motor oils (diesel engine oils) had been overbased to boost the TBN value of the oil and consequently had elevated levels of calcium. The results for calcium on these overbased oils are shown in Figure 2.

[Figure 2] Calcium in overbased oils as determined with ICP and RDE.

For the high-concentration samples, the RDE method significantly underestimates the actual concentration (correlation factor 2.5) but still shows a high degree of correlation (R2=0.99).

Figure 3 shows the repeatability of the tests and the ERAOIL results shows very high repeatability for majority of parameters.

[Figure 3] High repeatability of ERAOIL results on the majority of parameters.

For the overbased oils, the results of RDE without sample preparation will underestimate the calcium concentration. As the different oils all had different additive packages, it is likely that this effect is general and applies to all types of calcium detergents used to overbase oils. However, the correlation between RDE without sample preparation and ICP is still excellent (R2=0.99), which shows that the difference in absolute values can be accounted for in the calibration procedure for overbased oils. The more cumbersome alternative is to employ the same sample preparation procedure for both methods.

Conclusion

Measuring the elemental content in all types of lubricants is essential to ensure their performance, reliability and longevity, as well as that of the machines in which they are used. Regular analysis detects wear metals, providing information on the wear rate of parts, contributing to predictive maintenance and preventing breakdowns. It also identifies contaminants and detects additive depletion that affects lubricant performance. Typically, oil analysis is performed for this purpose using either an inductively coupled plasma (ICP) or rotating disk electrode (RDE) device. ICP provides accurate results with prior sample preparation, while RDE is much easier to use and provides comparable results. A comparative study has shown that the measurement results between ICP and RDE generally correlate very well.

To compare ERAOIL from Eralytics, Inductively Coupled Plasma (ICP) analysis, it’s important to consider various factors such as technology, application, precision, advantages, and limitations. Here’s a detailed comparison:

Technology

• ERAOIL (Eralytics):
  • Technology: Uses patented QES (Quantum Electronics Source) technology.
  • Principle: Based on optical emission spectrometry (OES).
• ICP (Inductively Coupled Plasma):
  • Technology: Uses an argon plasma to excite atoms and ions.
  • Principle: Measures the emitted light from excited atoms/ions to quantify element concentrations.

Applications

• ERAOIL:
  • Applications: Used for wear metal analysis, contaminants, and additive elements in lubricants and oil.
  • Typical Use Cases: Condition monitoring of engines and industrial machinery.
• ICP:
  • Applications: Broad range, including environmental analysis, metallurgy, pharmaceuticals, food safety, and lubricants.
  • Typical Use Cases: Detection and quantification of trace elements in various matrices.

Precision and Accuracy

• ERAOIL:
  • Precision: High precision with consistent results.
  • Accuracy: Accurate for routine oil analysis and monitoring.
• ICP:
  • Precision: Very high precision, capable of detecting parts per billion (ppb) levels.
  • Accuracy: Extremely accurate and reliable for trace element analysis.

Advantages

• ERAOIL:
  • Advantages: Quick analysis, low operating cost, minimal sample preparation.
  • Portable: Some models are designed to be portable and user-friendly.
• ICP:
  • Advantages: Extremely sensitive and accurate, can handle complex matrices, multi-element analysis.
  • Versatile: Suitable for a wide range of applications beyond just oil analysis.

Limitations

• ERAOIL:
  • Limitations: Primarily focused on oil and lubricants, not suitable for broader applications. It can’t analyze particles with more than 10 microns.
  • Element Range: Limited to specific elements relevant to oil analysis.
• ICP:
  • Limitations: Requires significant sample preparation, higher cost of operation, and more extensive training for operators. It can’t analyze particles with more than 4 microns.
  • Equipment: Generally more complex and less portable.

Cost and Maintenance

• ERAOIL:
  • Cost: Moderate initial investment, low operational cost.
  • Maintenance: Minimal maintenance required.
• ICP:
  • Cost: High initial investment, high operational cost.
  • Maintenance: Requires regular and extensive maintenance.

Summary

• ERAOIL is ideal for quick, on-site oil analysis with a focus on lubricants and wear metals.
• ICP offers high precision and versatility for trace element analysis across various applications but is more expensive and complex.

Conclusion

ERAOIL from Eralytics offers a different approach for oil analysis compared to ICP due to its quick and efficient analysis, cost-effectiveness, user-friendly operation, portability, and specific focus on oil analysis. While ICP provides extremely high precision, its complexity and cost make it less suitable for routine oil analysis. Problems associated with ICP usage are high initial and operational costs, significant sample preparation and a controlled laboratory environment requirement, extensive training requirement for operators, overkill precision for routine oil analysis needs, and inability to analyze particles with more than 4 microns. Therefore, for most oil analysis applications, particularly those focused on wear metals, contaminants, and additives in lubricants, ERAOIL is the optimal choice.

The newly engineered CuDDI (Copper Digital Detection Imaging) by VISAYA is an advanced copper corrosion detection system that sets a new standard in copper quality analysis for various industries. CuDDI is a state-of-the-art copper quality analysis device designed to deliver rapid and accurate measurements of corrosivity in oil or petroleum products. Utilizing a high-resolution camera with optical intelligence, CuDDI identifies exact levels of corrosivity through an automated vision algorithm and classification process. Results are digitally recorded using software to ensure that it is precise and the process is easily repeatable.

Key Features and Benefits

Higher Precision and Elimination of Bias: CuDDI’s design eliminates guesswork and operator bias by automating the detection process. The digital detection imaging is achieved through a vision algorithm that records, and shows an accurate corrosivity ratings in seconds as the outcome.

User-Friendly Operation:

• Easy-to-use interface and automated process
• High repeatability
• Data storage, USB and enhanced connectivity
• High resolution digital images, notes and graphs as results which can be shared easily
• Quick and reliable results
• Compact and robust design

Real-World Impact

CuDDI’s advanced optical detection technology significantly enhances the throughput and
reliability of corrosion testing in laboratories and industrial settings. By providing precise
monitoring of copper corrosion, CuDDI helps to prevent machinery damage, optimize
performance, and ensure regulatory compliance.

Industry Standards and Compliance

CuDDI adheres to multiple ASTM standards such as ASTM D130, ASTM D1838, and
ASTM D4048, making it a reliable tool for a wide range of petroleum products including
gasoline, diesel, and lubricants.

Applications Across Industries

CuDDI’s advanced technology is applicable across various industries, ensuring compliance
with industry standards and enhancing operational efficiency.

Refinery and Petrochemical Operations

• Provides accurate certification of finished products and fuel blending before distribution to meet specific quality standards and regulatory requirements.

Aviation Industry

• Performs jet fuel analysis to ensure fuel quality meets the standards for safety and performance.
• Test on fuels with contamination, to prevent potential maintenance and safety hazards.

Electrical and Power Generation Industries

• Monitors the condition of copper used in electrical systems to prevent corrosion-related failures.
• Ensures the integrity of copper components in transformers, and other electrical equipment.
• Helps in the quality assurance of high-voltage power lines and electrical substations by assessing the quality of copper conductors.

Oil and Gas Industry

• Assesses the corrosion rate of copper used in downhole and surface equipment to prevent failures and leaks.

Environmental Monitoring

• Analyzes the rate of copper degradation to assess their environmental impact.
• Helps industries comply with environmental regulations by providing accurate data on fuel properties and their impacts.

Research and Development

• Assists in the development and testing of new fuel formulations such as ethanol and biodiesel based fuels and their effects on copper products and to meet strict environmental regulations.

Automotive Industry

• Tests automotive fuel blends for corrosivity to ensure long-term engine performance and reliability.

Lubricant and Hydraulic Fluids Industry

• Ensures the quality of lubricants and hydraulic fluids used in various industrial applications by assessing their corrosive properties.
• Monitors the corrosivity of synthetic and mineral oils used in steam and gas turbines.

Are traditional viscometers and density meters limiting your lab’s efficiency and accuracy? The ERAVISC X brings a cutting-edge solution that integrates density and kinematic viscosity measurements into one compact, reliable unit. With faster results, improved usability, and versatile testing capabilities, this device is built to elevate your laboratory’s performance.

The ERAVISC X is designed to address common challenges in viscosity and density testing. Traditional methods can be time-consuming, inaccurate, inconsistent, and labor-intensive, requiring frequent cleaning, recalibration, and multiple devices to handle different sample types. This means increased costs and reduced efficiency.

The ERAVISC X changes the game with features like:

• Dual measurement capabilities: Simultaneously measure density and kinematic viscosity with high precision.
• Durability: With a viscosity chamber made of Hastelloy, the unit offers robust resistance to corrosion, making it ideal for testing any liquid sample.
• Efficiency: Obtain results in less than a minute with a throughput of up to 40 tests per hour.
• Ease of cleaning: Cleaning is simple, automated and efficient with recommended solvents (IPA, acetone, or toluene) for different sample types within about 2 minutes.
• Wide operating range: Measure viscosity from 1 to 1,000 mm²/s with an impressive accuracy of 0.8% and repeatability of 0.25%. The temperature range spans 7.5 to 100 ºC, with accuracy as precise as 0.02 ºC.

Why Choose ERAVISC X?

Compared to other viscometers, the ERAVISC X stands out for its speed, lightweight design, and affordability. It simplifies calibration, accommodates testing at two different temperatures, and provides faster, easier cleaning, making it ideal for labs looking to maximize efficiency without compromising on quality.

Key Benefits:

• Speed: Perform up to 40 tests per hour.
• Cost-effectiveness: Minimize operational time and costs.
• Flexibility: Conduct API viscosity measurements at various temperatures and handle a wide range of sample types and temperature with ease.
• Design: Compact and portable design optimizes lab space and workflow.

The ERAVISC X is the smart choice for modern labs seeking a versatile, high-performance alternative to conventional equipment. Whether you’re handling oil-based or water-based samples, testing corrosive substances, or aiming to reduce testing turnaround times, this unit delivers unmatched reliability and simplicity.

Transform your laboratory efficiency today!

Discover the benefits of ERAVISC X and achieve unparalleled precision, productivity, and cost savings.

This method uses the reaction of Iodine (I2) with water (Karl Fischer Reaction) to determine the amount of moisture in a polymer sample. This test method is intended to be used for the determination of moisture in most plastics. Plastics containing volatile components such as residual monomers and plasticizers are capable of releasing components that will interfere with the I2 + water reaction.

This method is suitable for measuring moisture over the range of 0.005 to 100 %. Sample size shall be adjusted to obtain an accurate moisture measurement.

NOTE 1: This standard is equivalent to ISO 15512 Method B.

“ASTM has developed more than 25 Standard Test Methods for the determination of moisture in a vast range of products and materials utilizing the Karl Fischer reaction. The accurate determination of water content in crude oils and hydrocarbons is vital to quality assessment, quality control, refining, handling, transportation and sales.
Method D6869-17 is under the jurisdiction of Subcommittee D20.70 on Plastics.”

Referenced Documents

ASTM Standards:

D1193 Specification for Reagent Water
D1298 Test Method for Density, Relative Density, or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method
D4052 Test Method for Density, Relative Density, or API Gravity of Liquids by Digital Density Meter
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D5854 Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products
E203 Test Method for Water Using Volumetric Karl Fischer Titration

Summary of Test Method

An aliquot is injected into the titration vessel of a coulometric Karl Fischer apparatus in which iodine for the Karl Fisher reaction is generated coulometrically at the anode. When all of the water has been titrated, excess iodine is detected by an electrometric end point detector and the titration is terminated. Based on the stoichiometry of the reaction, 1 mol of iodine reacts with 1 mol of water; thus, the quantity of water is proportional to the total integrated current according to Faraday’s Law. The sample injection can be done either by mass or volume. The viscous samples can be analyzed by using a water vaporizer accessory that heats the sample in the evaporation chamber, and the vaporized water is carried into the Karl Fischer titration cell by a dry inert carrier gas.

Significance and Use

Moisture will affect the process ability of some plastics. High moisture content causes surface imperfections (that is, splay or bubbling) or degradation by hydrolysis. Low moisture (with high temperature) causes polymerization. The physical properties of some plastics are affected by the moisture content.

Apparatus

Coulometric Karl Fischer Apparatus (using electrometric end point)—A number of automatic coulometric Karl Fischer titration assemblies consisting of titration cell, platinum electrodes, magnetic stirrer, and a control unit are available on the market. Instructions for operation of these devices are provided by the manufacturers and are not described herein. Figure 12 and 2 shows different models including head space and viscous sample accessories for solids, liquids, resins and gases applications.

Water Vaporizer Accessory—A number of automatic water vaporizer accessories are available on the market. Instructions for the operation of these devices are provided by the manufacturers and are not described herein.
Syringes—Samples are most easily added to the titration vessel by means of accurate glass or disposable plastic syringes with “luer” fittings and hypodermic needles of suitable length to dip below the surface of the anode solution in the cell when inserted through the inlet port septum. The bores of the needles used shall be kept as small as possible, but large enough to avoid problems arising from back pressure or blocking while sampling. Suggested syringe sizes are as follows:

10 µL, with a needle long enough to dip below the surface of the anode solution in the cell when inserted through the inlet port septum and graduated for readings to the nearest 0.1 µL or better. This syringe can be used to accurately inject a small quantity of water to check reagent performance as described in the Calibration Section.

As identified in Table 1(D6304), syringes of the following capacities: 250 µL accurate to the nearest 10 µL; 500 µL accurate to the nearest 10 µL; 1 mL accurate to the nearest 0.01 mL; 2 mL accurate to the nearest 0.01 mL; and 3 mL accurate to the nearest 0.01 mL. A quality gas-tight glass syringe with a TFE-fluorocarbon plunger and “luer” fitting is recommended.

[Figure 1] Aquamax Pro Oil Karl Fischer Titrator

[Figure 2] Aqua Head Space Vario Titrator

Interferences

A number of substances and classes of compounds associated with condensation or oxidation-reduction reactions interferes in the determination of water by Karl Fischer titration. In petroleum products, the most common interferences are mercaptans and sulfides. At levels of less than 500 mg ⁄kg as sulfur, the interference from these compounds is insignificant for water concentrations greater than 0.02 % by mass. For more information on substances that interfere in the determination of water by the Karl Fischer titration method, see Test Method E203. Some interferences, such as ketones, may be overcome if the appropriate reagents are used.

The significance of the mercaptan and sulfide interference on the Karl Fischer titration for water in the 10 mg ⁄kg to 200 mg ⁄kg range has not been determined experimentally. At these low water concentrations, however, the interference may be expected to be significant for mercaptan and sulfide concentrations of greater than 500 mg ⁄kg as sulfur.

The Aquamax KF PRO Oil shown in Fig.1 is the perfect instrument to measure ppm water in oils and fuels without the worry of interference side reactions caused by additives or S/SH-. The unique “closed loop” concept illustrated in Fig.4 avoids methanol to evaporate from the KF reagent. Meaning no additional carrier gas necessary. Directly injecting the sample in to the oven means no blank value is required, making the Aquamax KF PRO Oil a truly accurate, trace level water in petroleum products titrator.

[Figure 3] Closed Loop Carrier Gas design

This test method is intended for use with commercially available coulometric Karl Fischer reagents and for the determination of water in additives, lube oils, base oils, automatic transmission fluids, hydrocarbon solvents, and other petroleum products. By proper choice of the sample size, this test method may be used for the determination of water from mg/kg to percent level concentrations.

“ASTM has developed more than 25 Standard Test Methods for the determination of moisture in a vast range of products and materials utilizing the Karl Fischer reaction. The accurate determination of water content in crude oils and hydrocarbons is vital to quality assessment, quality control, refining, handling, transportation and sales.”

Referenced Documents

ASTM Standards:

D1193 Specification for Reagent Water
D1298 Test Method for Density, Relative Density, or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method
D4052 Test Method for Density, Relative Density, or API Gravity of Liquids by Digital Density Meter
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D5854 Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products
E203 Test Method for Water Using Volumetric Karl Fischer Titration

Summary of Test Method

An aliquot is injected into the titration vessel of a coulometric Karl Fischer apparatus in which iodine for the Karl Fisher reaction is generated coulometrically at the anode. When all of the water has been titrated, excess iodine is detected by an electrometric end point detector and the titration is terminated. Based on the stoichiometry of the reaction, 1 mol of iodine reacts with 1 mol of water; thus, the quantity of water is proportional to the total integrated current according to Faraday’s Law. The sample injection can be done either by mass or volume. The viscous samples can be analyzed by using a water vaporizer accessory that heats the sample in the evaporation chamber, and the vaporized water is carried into the Karl Fischer titration cell by a dry inert carrier gas.

Significance and Use

Coulometric Karl Fischer (KF) titration is a highly accurate technique employed for moisture determination in non-aqueous solvents. A knowledge of the water content of lubricating oils, additives, and similar products is important in the manufacturing, purchase, sale, or transfer of such petroleum products to help in predicting their quality and performance characteristics.

For lubricating oils, the presence of moisture could lead to premature corrosion and wear, an increase in the debris load resulting in diminished lubrication and premature plugging of filters, an impedance in the effect of additives, and undesirable support of deleterious bacterial growth.
This test method is intended for use with commercially available coulometric Karl Fischer reagents and for the determination of water in additives, lube oils, base oils, automatic transmission fluids, hydrocarbon solvents, and other petroleum products. By proper choice of the sample size, this test method may be used for the determination of water from mg/kg to percent level concentrations.

Apparatus

Coulometric Karl Fischer Apparatus (using electrometric end point)—A number of automatic coulometric Karl Fischer titration assemblies consisting of titration cell, platinum electrodes, magnetic stirrer, and a control unit are available on the market. Instructions for operation of these devices are provided by the manufacturers and are not described herein. Figure 1,2 and 3 shows different models including head space and viscous sample accessories for solids, liquids, resins and gases applications.

Water Vaporizer Accessory—A number of automatic water vaporizer accessories are available on the market. Instructions for the operation of these devices are provided by the manufacturers and are not described herein.
Syringes—Samples are most easily added to the titration vessel by means of accurate glass or disposable plastic syringes with “luer” fittings and hypodermic needles of suitable length to dip below the surface of the anode solution in the cell when inserted through the inlet port septum. The bores of the needles used shall be kept as small as possible, but large enough to avoid problems arising from back pressure or blocking while sampling. Suggested syringe sizes are as follows:

10 µL, with a needle long enough to dip below the surface of the anode solution in the cell when inserted through the inlet port septum and graduated for readings to the nearest 0.1 µL or better. This syringe can be used to accurately inject a small quantity of water to check reagent performance as described in the Calibration Section.

As identified in Table 1(D6304), syringes of the following capacities: 250 µL accurate to the nearest 10 µL; 500 µL accurate to the nearest 10 µL; 1 mL accurate to the nearest 0.01 mL; 2 mL accurate to the nearest 0.01 mL; and 3 mL accurate to the nearest 0.01 mL. A quality gas-tight glass syringe with a TFE-fluorocarbon plunger and “luer” fitting is recommended.

Abstract

The Environmental Protection Agency (EPA) recently amended the source performance standards for volatile organic liquid and petroleum liquid storage vessels. The EPA published the final rule in the Federal Register Citations (FRC) for new source performance standards (NSPS) on September 30th, 2024. The amendments and additions were added to the code of federal regulations (CFR) citations under 40 CFR Part 60 Subpart Kb with a new section known as Subpart Kc.

These new amendments reduced the vapor pressure applicability thresholds to a maximum true vapor pressure (MTVP) greater than or equal to 10.3 kPa and MTVP greater than or equal to 3.4 kPa depending on the volume in which they are stored. The NSPS also revised the general applicability thresholds for reporting to 1.7 kPa. With these new storage tank emissions standards, new additional lower explosive limit (LEL) monitoring and design/operating requirements to ensure compliance have also been established specific to the infrastructure of the storage tanks. The technical methods for determining the vapor pressure have also been changed from ASTM D2879 to the D6277/D6378 methods. Among the above emissions standards within Subpart Kc, amendments to NSPS Subpart Kb have been established to apply to VOC liquid and petroleum liquid storage vessels and also add electronic reporting requirements. Affectability is highly specific to a wide variety of factors like geographic location, volume, and tank design so find the full specifications under EPA 40 CFR Part 60 Subpart Kb and Kc.

The goal of these revisions of the emissions standards is to expand air pollution controls to a wider range of storage vessels than is currently regulated under the current NSPS. The finalized VOC storage tank emissions standards achieve an industry-wide 98% control efficiency for VOCs compared to the most recent NSPS which requires only 95% control efficiency.

Volatility and Vapor Pressure

Volatility has always been a physical characteristic of note because it describes how readily a chemical vaporizes at a given temperature and pressure. A substance with high volatility also has high vapor pressure, but the two are not necessarily the same thing. Vapor pressure is the quantitative measure of the pressure exerted by the vapor of a substance in a closed system at a given temperature, whereas volatility is a qualitative descriptor describing vaporization tendency.

Regulatory agencies like the Environmental Protection Agency (EPA) are invested in vapor pressure and volatility because when these chemicals evaporate into the air and atmosphere, they contribute to adverse health effects on people and the environment. Because of the dangers associated with volatile organic compounds (VOCs) specifically, regulations are in place to limit the emission output of larger-scale operations. Highly volatile chemicals like gasoline are heavily regulated to ensure their emissions into the environment are limited. Even compounds with low vapor pressures can contribute to human health and environmental issues when they exist in high enough quantities. Due to their contributions to things like ground-level ozone which decreases air quality and damages forest and crop health, storage facilities with high-volume tanks containing both of these high and low vapor pressure compounds must calculate and report their emission output to comply with these regulatory agencies.

Regulatory Emission Factors

The EPA has an extensive document, AP-42, which is the chief compilation of the EPAs emission factor information. An emission factor is a representative value that attempts to relate the quantity of a pollutant with an activity associated with the release of the pollutant. Emission factors are fundamental tools in developing emission control strategies. Typically, the mass of the pollutant is divided by a unit volume, mass, distance, or duration of the activity emitting the pollutant. The general equation for these emission estimates is:

𝐸 = 𝐴 × 𝐸𝐹 ( 1 − ^𝐸𝑅⁄₁₀₀ )
Where:
𝐸 = emissions
𝐴 = activity rate
𝐸𝐹 = emission factor
𝐸𝑅 = overall emission reduction efficiency

These variables provide an estimate of the emission levels of pollutants from various sources or industries, in which AP-42 details extensively. Each chapter focuses on a specific type of source like biogenic sources or industries like the petroleum industry, and chapter seven revolves around the output of emissions from stationary organic liquid storage tanks. This chapter is becoming increasingly important due to the recent amendments and additional regulations that require the calculation of estimated emissions to maintain compliance for these extensive tank networks containing all types of compounds.

1. Fixed Roof Tanks

^L_T = ^L_S + ^L_W

Where:
     ^L_T = total routine losses, lb/yr

     ^L_S = standing losses, lb/yr

     ^L_W = working losses, lb/yr

Expanded:

2. Floating Roof Tanks

^L_T = ^L_S + ^L_W

Where:
     ^L_T = total routine losses, lb/yr

     ^L_S = standing losses, lb/yr

     ^L_W = withdrawal losses, lb/yr

Expanded:

*These equations do not take into account or display filling, landing, purging, and flashing losses. Variable and derivative information can be found extensively in Chapter 7 of AP-42. These equations are a function of tank capacity, vapor pressure of the stored liquid, utilization rate of the tank, and atmospheric conditions of the tank location. The equations are derived from a theoretical energy transfer model. Some default parameters were assigned values to simplify the calculations based on this energy transfer model. The accuracy of the resultant equations are dependent on the likeness in which the storage containers under review fit the assumptions made for that specific subdivision of tank type.

Vapor Pressure as Variables

As can be seen by the above equations, vapor pressure values ( ^P_VX , ^P_VN , ^P_VA)are a critical variable in emission output from these storage tanks.

     ^P_VX = Vapor pressure at average daily maximum liquid surface temperature, psia.

     ^P_VN = Vapor pressure at average daily minimum liquid surface temperature, psia.

     ^P_VA = Vapor pressure at average daily liquid surface temperature, psia.

     P = True vapor pressure, psia.

Vapor pressure clearly contributes to emission factors in an extensive manner. Containers and tanks storing high vapor pressure liquids like VOCs and petroleum liquids drastically contribute to air pollution and this is why these liquids are the focus of the EPA.

New Source Performance Standards (NSPS) – Subpart K

The EPA exists as the statutory authority over these storage tank emissions standards as granted by the CAA section 111. This section explains the notion of governance of standards of performance for stationary sources contributing to air pollution. These emissions standards are referred to as new source performance standards (NSPS) and the EPA has the scope to define the source categories, determine the applicability of compounds, set regulation levels, and distinguish between categorical delineations within classes themselves. The EPA is required to review these standards every eight years, and revise if necessary.

To set or revise these standards, the EPA must analyze “the degree of emission limitation achievable through the application of the best system of emission reduction (BSER) which (taking into account the cost of achieving such reduction and any non-air quality health and environmental impact and energy requirements) the Administrator determines has been adequately demonstrated” (CAA section 111(a)(1)).

Current Subpart Kb

The first petroleum liquid storage NSPS was promulgated in 1974 under NSPS subpart K, and was amended multiple times leading up to 1980. VOC storage was not added to the vessels under regulation until it was proposed in 1984 and codified in 1987 under subpart Kb. NSPS subpart Kb has two sets of applicability thresholds: one for determining affected facilities and the other for determining which of these facilities require controls. Subpart Kb regulates storage vessels with a 20,000 gallon or more capacity with true vapor pressures of more than 15.0 kPa, and storage tanks with a 40,000 gallon or more capacity with a true vapor pressure value of more than 3.5 kPa. Controls are required for 20,000 gallon or more vessels with true vapor pressure values over 27.6 kPa, and from 40,000 or more gallon tanks with values greater than 5.2 kPa. These controls require the use of floating roofs: either internal or external roofs with supplemental vent systems and other control devices. Both require gaskets and rim seals to prevent vapor escape into the atmosphere.

Amendments and Additions to Subpart K

Following the scheduled review of subpart K, after using BSER assessments alongside predictive emission factor modeling using the equations above from chapter 7 of AP-42, and compared to the estimated cost effectiveness and impact on the environment and economy, the EPA proposed revisions to the NSPS subpart Kb alongside the addition of subpart Kc. The major revisions and additions can be found below:

1. Simplified Applicability Threshold

The first major proposal lowers the threshold for applicability to 1.7 kPa. This means any storagevessel greater than 20,000 gallons containing VOCs or petroleum liquids that has extremely low vapor pressures will not be subject to subpart Kc regulations without having to meet the prerequisite vapor pressure level. This amendment establishes a baseline for monitoring and recordkeeping in tanks that have very low vapor pressure emission properties.

2. Revision of Controls Applicability

Another major revision includes the lowering of the threshold for facilities to have controls in place. Vessels between 20,000 and 40,000 gallons with a true vapor pressure greater than or equal to 10.3 kPa and vessels above 40,000 gallons with a value of 3.4 kPa are required to have controls in place to further reduce emissions.

3. Storage Control Compliance

The EPA has also opted to include more specific requirements for vessel design to limit standing emissions. For tanks with a vapor pressure less than 76.5 kPa, an internal floating roof with enhanced rim seals is required. The storage tank emissions standard designates the vessel must have a liquid-mounted or mechanical shoe primary seal and rim-mounted secondary seal to be in compliance. Tanks in compliance with these standards were found to have 98% control efficiency. Some external floating roofs with extensive and adequate closed vents and controls can achieve the 98% control which can be used as an alternate form of compliance.

For tanks holding VOC and petroleum liquids with vapor pressures greater than 76.5 kPa, a closed vent system with a control device must be installed and also achieve 98% control efficiency.

4. Lower Explosive Limit Monitoring

The current standard only requires inspections of internal floating roof systems with dual seals every five years, but under the new guidelines, annual inspections must be performed alongside lower explosive limit (LEL) monitoring of the headspace to more readily identify malfunctioning vessels. This addition is a less subjective means to monitor and verify performance of the floating roofs.

5. Technical Methods for VP Determination

The current method for determining vapor pressure values for proper operation, monitoring, and reporting is designated as the American Society for Testing and Materials (ASTM) D2879. However, the new guidelines are switching the technical method for determining these values to ASTM D6378-22 and D6377-20. These methods are automated and produce more accurate vapor pressure measurements.

ASTM D6378-22 “Standard Test Method for Determination of Vapor Pressure (VPX) of Petroleum Products, Hydrocarbons, and Hydrocarbon-Oxygenate Mixtures (Triple Expansion Method),” is used for measuring vapor pressures between 7 kPa and 150 kPa. ASTM D6377-20 “Standard Test Method for Determination of Vapor Pressure of Crude Oil: VPCRx (Expansion Method),” is used for measuring vapor pressures between 29 kPa and 180 kPa. For each analysis, you must use a 4:1 vapor to liquid ratio.

6. Electronic Reporting Requirements

Operators will also be required to submit monitoring reports electronically to the central data exchange which will enhance the usefulness of the information.

Affected Parties and Effective Outcomes

The EPA estimated that approximately 240 new storage vessels become subject to the NSPS subpart Kb every year, such that 1,200 new storage vessels could become subject to NSPS subpart Kc over the next five years if no change in thresholds is adopted.

It was projected that with lower vapor pressure thresholds, approximately 20 percent more storage vessels could become subject to the NSPS subpart Kc standards each year.

The lowered control applicability thresholds yield emission reductions at a cost of $6,000 to $7,000 per ton of VOC reduced.

The EPA estimates a reduction of VOC emission by 1,085 tons per year.

Based on 2022 values, the revision will cost approximately $20.6 million in total capital cost and result in total annualized savings of $4.48 million per year including product recovery.

Summary of Amendments

Under the new storage tank emissions standards released by the EPA revising subpart Kb and adding subpart Kc, any VOC and petroleum liquid storage vessel over 20,000 gallons with a vapor pressure above 1.7 kPa is subject to monitoring and reporting emissions. The vapor pressure applicability threshold requiring storage vessels to have controls in place was also decreased from 15.0 kPa to 10.3 kPa for tanks with a volume between 20,000 and 40,000, with any vessel greater than 40,000 gallons requiring controls with a vapor pressure greater than 3.4 kPa (threshold decreased from 3.5 kPa). The equipment standard was also updated mandating 98% control efficiency (increase form 95%) using an internal floating roof with a dual seal system for vessels with vapor pressure values less than 76.5 kPa, and requiring a closed vent system with controls for tanks greater than 76.5 kPa. The revisions also mandate annual roof inspections with lower explosive limit (LEL) measurements. The technical method for the determination of vapor pressure values has also switched from ASTM D2879 to ASTM D6378-22 and D6377-20 in efforts to produce more accurate vapor pressure values. All monitoring values and data are also now required to be submitted electronically to the central data exchange.

For more information on all of the amendments and additions to the NSPS and other resources related to these storage tank emissions standards, including how you specifically will be affected, navigate to the NSPS publication.

Introduction

The determination of the Reid Vapor Pressure (RVP) in finished gasoline and other fossil fuels is without a doubt the starting point in their product characterization¹. Finished gasolines are products blended from a series of fractions that range from straight distillates, ethanol, and other oxygenates to streams from different catalytic conversion processes. This complex yet fundamental refinery operation is illustrated in Figure 1.

Figure 1. The Gasoline Blending Process

Refiners are faced with an enormous challenge, especially in on-line blending operations, as they must observe the different quality grades to comply with federal regulations. Additionally, they must also observe seasonal specifications, keeping in focus the optimum use of the components to increase profitability in terms of produced volumes and avoid unnecessary quality giveaways. These giveaways can represent an average figure of around 0.5 US$/barrel, which can surmount to a loss of hundreds of millions of dollars per year for producers.  In terms of octane numbers, if the specification is set to 87.0, then 0.1 octane giveaway represents approximately 1,000,000 US$ for every 100,000 barrels of crude oil processed. Considering the competitive nature and narrow margins of the refinery business, this can easily translate to bankruptcy for the company.

In short, the greater refiners’ blending flexibility, the greater the profitability of their commercializing strategies. To illustrate the importance of RVP in gasoline blending economics, refiners aim at producing the optimum RVP value without going outside specifications. When blended with gasoline, a barrel of n-butane that costs US$ 7/barrel can be sold for 25$/barrel. This $18 profit makes the blending process absolutely critical in optimizing refinery operations.

However, another important factor not to be overlooked in terms of profitability is the reliability of the analytical equipment used in determining quality parameters. Nowadays, in-line blending is a computer-controlled process that monitors not only the final properties of the gasoline, but also the stock inventories and their respective physical properties. Many of these quality parameters fail to display a linear behavior, so when operators are limited to Linear Programming models to produce maximum final volumes of products, results are less than ideal. Any adjustments to the operations to avoid losses must then also be performed spontaneously, taxing operators as speed and accuracy of analyses are stressed.

In attempts to increase the butane concentration to maximize the final volume of blended gasoline, the refiner also faces an additional challenge in incorporating compressed gases into liquid mixtures. RVP measurements² and the advantages of ERAVAP ONLINE in gasoline blending deserve special consideration in this process.

Liquified Gases Into Liquid Fuel Blending Process

While a simple process theoretically, introducing LPG’s into a liquid fuels requires some imperative considerations. First among these is that the downstream process or storage is not designed for gaseous fuels. Therefore, a system which allows straight LPG’s to slip through will produce environmental and safety consequences. Floating roofs, flares, vapor recovery systems, and mechanical vents are all typically incapable of handling even moderate amounts of Petroleum Gas.

Flow measurement errors and other inaccuracies can produce significant volumes of products off-specification. A blend system should ensure a rapid homogenization both to prevent downstream phase separation and to provide for a representative sample to the analyzers. Just a few steps are required to ensure the LPGs remain in their liquid state.

First, an LPG transfer pump is essential.  It is common to use positive displacement pumps of the sliding vane type to transfer LPG’s. However, the vacuum capabilities of such pumps can produce a phase change in these gases, which may not return to a liquid state prior to injection. Further, cavitation created vibrations can wreak havoc on the downstream piping and instruments. To solve this problem, operators can either carefully monitor the pump’s vacuum level and manipulate the pump speed, or, more ideally, the system can employ a centrifugal pump, such as a vertical turbine, which has limited vacuum characteristics.

Second, the use of a Coriolis mass flowmeter for measuring the LPG is a given. These meters provide crucial density information, which is used by the control system to detect the gaseous phase. The control system is then directed to perform a corrective action, as needed. To avoid vapor lock conditions, the blend system should include an automated valve to direct the gaseous LPG from the injection point back to the storage tank through a vapor line.

Once the liquid phase is assured in the transfer line, flow control valves are used to proportion the LPG. The system may use two valves in parallel to allow for 100:1 turn down ratios, if required. This allows each valve to operate within the 10:1 range, ensuring maximum precision. Placement of one or two automated ball valves prior to entry into the liquid fuel or crude line eliminates the threat of bleeding.

Next, the system must produce a homogenous mechanical bond with the liquid fuel prior to being exposed to the reduced pressures found downstream. A simple and low cost static mixer is most common for producing this bond, however, these mixers have limitations in the form of both a pressure drop as well as a minimum velocity requirement. In this case, the use of a jet mixer is ideal. Jet mixers utilize recirculation pumps, drawing fluid from downstream and returning it upstream through a mixing nozzle. The mixing nozzle creates enough turbulence to ensure the homogeneity necessary for the bond.

Figure 2. Eravap Online

Once the blended product is free of gas, it can be analyzed for conformance to the desired vapor pressure. The blend system requires a fast loop that extracts the product through a quill and delivers it to the analyzer. If a jet mixer is used, then this is used as the fast loop. Otherwise an additional pump extracts the blended product, delivering it to the analyzer through a swirl filter and pressure-reducing regulator.

With a homogenous single phase product and a representative sample, targeting a specific RVP requires a time-consuming, multi-step mathematical procedure. Estimations of the final vapor pressure are conventionally calculated according to formulas detailed in any number of studies³.

The use of an RVP analyzer simplifies and hastens the entire gasoline blending process. The analyzer removes the necessity for prolonged conventional modeling; the automated control system easily and accurately calculates the blend ratio by first targeting a value of 75% of the desired pressure, with the final value being the sum of the RVPs of the LPG and Gasoline multiplied by the respected mass ratio.

Once the resultant blend is analyzed, the LPG is gradually increased to achieve the target RVP. Each step change in the LPG proportion is determined by measuring the effect of the previous step’s change’s on the RVP. These step changes are limited by the control system to ensure that the blended vapor pressure never exceeds the proposed limit.​

Figure 2. ERAVAP Online, available through Ayalytical Instruments Refiners adhere to a general understanding that online blending operations are less risky when they can be performed quickly and in small batches. The ERAVAP ONLINE vapor pressure analyzer, shown in Figure 2, is an RVP analyzer available through Ayalytical Instruments that not only reduces blending operation risks, but increases measurement accuracy. ERAVAP ONLINE, with its fast, reliable results, ensures in spec gasoline blendstocks⁴, allowing for rapid production at a fraction of the cost. Inaccurate flow measurements and unreliable RVP determinations among other important quality parameters cause the product to be segregated in Off-Specifications tanks demanding cost intensive hours to upgrade it. This vapor pressure analyzer guarantees compliance with the EPA 40 CFR 80 D protocol for Tier III Reformulated Gasoline that establishes the RVP parameter, in Section 80.27, to be evaluated by a highly stable, precise, and accurate instrument. ERAVAP ONLINE easily meets this performance-based measurement criteria for precision and accuracy.

Experimental Results

Figure 3. FAT ERAVAP ONLINE Data dispersion

The stability of ERAVAP ONLINE is illustrated in Figure 3, which displays the results after an FAT over 180 continuous measurements for a period of 1.5 days. Figure 3 illustrates that all experimental values fall within two standard deviations for all replications. The rest of the parameters outlined via D6378 are listed in Table 1 below. ERAVAP results are clearly within the recommended instrument specifications stated in D6378.

Table 1. ASTM specifications.

Conclusions

ERAVAP ONLINE is an innovative, reliable, versatile and easy to operate RVP-testing instrument that reduces manual labor and error while increasing efficiency and profitability. Its triple expansion, hot swappable cells are stable and effortlessly configurable. The instrument is fully controllable via Modbus (TCP or RTU) or Touch Display for convenient remote or on-site operation. Furthermore, ERAVAP ONLINE provides for maximum productivity, allowing operators to simultaneously manage three streams, view eight control charts, and analyze 10 samples per hour. ERAVAP ONLINE is designed to process crude oils and all types of fuels. Fully ATEX certified, it guarantees full compliance with ASTM StandardsD6377, D6378, and D6897, and is versatile enough to correlate with standards D323, D5188, D5191, and EN 13016. The durable design of ERAVAP ONLINE satisfies the demands of fast-paced laboratories, with continuous 24/7 operation and minimal downtime during calibration, operation, and preventive maintenance. Its Piston-based measurement principle negates the need for an external vacuum pump, thereby eliminating associated vapor lock issues. The built-in sensors render astounding repeatability values within 0.3 kPa and reproducibility within 0.7 kPa at a pressure resolution of 0.01 kPa, providing a distinct advantage over conventional standard methods. The enhanced precision and accuracy of ERAVAP ONLINE optimizes blending operations by reducing quality giveaways, thereby increasing refiner profits. 

References

1. ASTM D6378 Annual Bok of Standards Vol. 05.03 January 2016
2. ASTM D6897 Annual Book of Standards vol. 05.03 January 2016
3. W. E. Stewart, “Predict RVP of Blends Accurately,” Petroleum Refiner (now Hydrocarbon Processing), Vol. 38, No. 6, June 1959, pp. 231 – 234.
4. G. Potten. The Art of Blending. Accuracy and Efficiency. Nical TB010-0607-2. World Bunker Magazine

ASTM D6377 test method covers the use of automated vapor pressure instruments to determine the vapor pressure exerted in vacuum of crude oils. This test method is suitable for testing samples that exert a vapor pressure between 25 kPa and 180 kPa at 37.8 °C at vapor-liquid ratios from 4:1 to 0.02:1 (X = 4 to 0.02).

NOTE 1—This test method is suitable for the determination of the vapor pressure of crude oils at temperatures from 0 °C to 100 °C and pressures up to 500 kPa, but the precision and bias statements may not be applicable.
This test method allows the determination of vapor pressure for crude oil samples having pour points above 0 °C.

“D6377 determines the vapor pressure of crude oils and crude oil blends by a single expansion method covering a wide range of samples and experimental conditions.
A precise determination of the vapor pressure of crude oils is a valuable diagnostic tool to:
_ Optimize the best route for their refining strategic programs.
_ Assist in determining the hazards associated with their storage and transportation especially by rail.
_ And finally, to bring the final product into specifications to maximize their commercial value.
Eralytics Eravap analyzer by means of its unique design and sophisticated piston-based measurement principle, guarantees precise, and accurate experimental results on the bench or Online for dead and live crude oils in 5 minutes….”

Referenced Documents

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 Oil: VPCRx (Expansion Method)
• D6377 Test Method for Determination of Vapor Pressure of Crude Oils
• D6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport to Measure the Same Property of a Material

Terminology

platinum resistance thermometer, n—temperature measuring device constructed with a length of platinum wire, whose electrical resistance changes in relation to temperature.
vapor-liquid ratio (V/L), n—the ratio of the vapor volume to the liquid volume of specimen, in equilibrium, under specified conditions.

Definitions of Terms Specific to This Standard:

dead crude oil, n—crude oil with sufficiently low vapor pressure that, when exposed to normal atmospheric pressure at room temperature, does not result in boiling of the sample.
Discussion—Sampling and handling of dead crude oils can usually be done without loss of sample integrity or other problems by using normal, non-pressurized sample containers such as cans.
live crude oil, n—crude oil with sufficiently high vapor pressure that it would boil if exposed to normal atmospheric pressure at room temperature.
Discussion—Sampling and handling live crude oils requires a pressurized sample system and pressurized sample containers to ensure sample integrity and prevent loss of volatile components.
Reid vapor pressure equivalent (RVPE), n—a value calculated by a defined correlation equation (see Eq X1.1) from VPCR4 at 37.8 °C that is expected to be equivalent to the vapor pressure value obtained by Test Method D323.
Discussion—The estimation of RVPE from Eq X1.1 is not universally applicable to all crude oils, it is recommended to report the VPCR4 (38.7 °C) result for a crude oil sample.
vapor pressure of crude oil (VPCR x), 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.

Abbreviations:

ARV, n—accepted reference value
RVPE, n—Reid vapor pressure equivalent
V/L, n—vapor liquid ratio
VPCRx, n—vapor pressure of crude oil at x vapor liquid ratio

Summary of Test Method

The vapor pressure described below faithfully follows the ASTM D6377. Please consult the current version of this standard test method for more details.
Employing a measuring chamber with a built-in piston, a sample of known volume is drawn from the sample container into the temperature-controlled chamber at 20 °C or higher.
After sealing the chamber, the volume is expanded by moving the piston until the final volume produces the desired V/L value. The temperature of the measuring chamber is then regulated to the measuring temperature.
After temperature and pressure equilibrium, the measured pressure is recorded as the VPCRX of the sample. The test specimen shall be mixed during the measuring procedure by shaking the measuring chamber to achieve pressure equilibrium in a reasonable time of 5 min to 30 min.
For results related to Test Method D323, the final volume of the measuring chamber shall be five times the test specimen volume and the measuring temperature shall be 37.8 °C.

Significance and Use

Vapor pressure of crude oil at various V/Ls is an important physical property for shipping and storage.
NOTE 2—A V/L ratio of 0.02:1 (X = 0.02) mimics closely the situation of an oil tanker.
Vapor pressure of crude oil is important to crude oil producers and refiners for general handling and initial refinery treatment.
The vapor pressure determined by this test method at a vapor-liquid ratio of 4:1 (VPCR4) of crude oil at 37.8 °C can be related to the vapor pressure value determined on the same material when tested by Test Method D323.
Chilling and air saturation of the sample prior to the vapor pressure measurement is not required.
This test method can be applied in online applications in which an air saturation procedure prior to the measurement cannot be performed.

Apparatus

The apparatus suitable for this test method employs a small volume, cylindrically shaped measuring chamber with associated equipment to control the chamber temperature within the range from 0 °C to 100 °C. The measuring chamber shall contain a movable piston with a minimum dead volume of less than 1 % of the total volume at the lowest position to allow sample introduction into the measuring chamber and expansion to the desired V/L. A static pressure transducer shall be incorporated in the piston. The measuring chamber shall contain an inlet/outlet valve combination for sample introduction and expulsion. The piston and the valve combination shall be at the same temperature as the measuring chamber to avoid any condensation or excessive evaporation.
The measuring chamber shall be designed to have a total volume of 5 mL to 15 mL and shall maintain a V/L of 4:1 to 0.02:1. The accuracy of the adjusted V/L shall be within 0.01.
NOTE 3—The measuring chambers employed by the instruments used in generating the precision and bias statements were constructed of nickel plated aluminum, stainless steel and brass with a total volume of 5 mL Measuring chambers exceeding a 5 mL capacity and different design can be used, but the precision and bias statement may not be applicable.
The pressure transducer shall have a minimum operational range from 0 kPa to 500 kPa with a minimum resolution of 0.1 kPa and a minimum accuracy of ±0.5 kPa. The pressure measurement system shall include associated electronics and readout devices to display the resulting pressure reading.
Electronic temperature control shall be used to maintain the measuring chamber at the prescribed temperature within ±0.1 °C for the duration of the test.
A platinum resistance thermometer shall be used for measuring the temperature of the measuring chamber. The minimum temperature range of the measuring device shall be from 0 °C to 100 °C with a resolution of 0.1 °C and an accuracy of ±0.1 °C.
The vapor pressure apparatus shall have provisions for rinsing the measuring chamber with the next sample to be tested or with a solvent of low vapor pressure.
The vapor pressure apparatus shall have provisions for shaking the sample during the measuring procedure with a minimum frequency of 1.5 cycles per second.
Vacuum Pump for Calibration, capable of reducing the pressure in the measuring chamber to less than 0.01 kPa absolute.
McLeod Vacuum Gage or Calibrated Electronic Vacuum Measuring Device for Calibration, to cover at least the range of 0.01 kPa to 0.67 kPa. The calibration of the electronic measuring device shall be regularly verified in accordance with Annex A of Test Method D2892.
Pressure Measuring Device for Calibration, capable of measuring local station pressure with an accuracy and a resolution of 0.1 kPa or better, at the same elevation relative to sea level as the apparatus in the laboratory.
NOTE 4—This standard does not give full details of instruments suitable for carrying out this test. Details on the installation, operation and maintenance of each instrument may be found in the manufacturer’s manual.