Chromatographs: A Key Technology in Natural Gas Analysis


In the oil and gas industry, precise analysis of raw materials and products is crucial for ensuring process quality, safety, and efficiency. The chromatographs are one of the most important tools used in this context.

These sophisticated instruments enable detailed analysis of sample components based on their separation properties in the liquid or gaseous phase. In this article, learn more about the role of chromatographs in the oil and gas industry.

What are chromatographs?

Chromatographs are instruments used for analyzing chemical mixtures. Chromatography is a technique that separates different components of a mixture based on their varying physical or chemical properties. In natural gas analysis, gas chromatography is the most commonly used method.

How chromatographs are used in natural gas analysis:

  1. Natural gas sample: A sample of natural gas is collected and prepared for analysis. This may include filtering, drying, or concentrating the sample.
  2. Injector: The analysis begins with a gas chromatograph, where the sample is introduced using an injector (manual or automatic autosampler). It is first heated to a gaseous state and then carried by the mobile phase (carrier gas) to the stationary phase in the column, interacting with the stationary phase and the sample.
  3. Carrier gas: The carrier gas is an inert gas used to transport the samples. Commonly used gases include helium (He), nitrogen (N2), hydrogen (H2), and argon (Ar). Helium is the most commonly used carrier gas in about 90% of instruments, although hydrogen is preferred for improved separations. High-purity gas with at least 99.995% purity should be used as the carrier gas, as it reduces initial noise.
  4. Chromatographic column: The column contains the stationary phase and the mobile phase. Sample components pass through the column at different rates, depending on their interactions with the stationary phase, resulting in separation.
  5. Detector: At the end of the column, the detector identifies and quantifies the separated components. Natural gas analysis commonly uses flame ionization detectors (FID) or thermal conductivity detectors (TCD).
  6. Data analysis: Data from the detector is analyzed using computer software, which generates a chromatogram. The chromatogram displays retention times and signal intensities for each component, enabling identification and quantification of the present compounds.

In natural gas analysis, gas chromatography allows for the determination of gas composition, including the presence of methane, ethane, propane, butane, and other hydrocarbons, as well as inorganic gases such as nitrogen, carbon dioxide, and hydrogen. This information is critical for assessing natural gas’s quality, energy value, and safety.

Purpose of the chromatograph

Chromatograph is an indispensable tool in the oil and gas industry. They enable precise sample analysis to determine their qualitative and quantitative compositions, ensuring products meet strict quality and safety standards.

Chromatographs analyze various samples, including raw materials (e.g., crude oil, natural gas), different oil fractions, and final products like fuels or lubricants. Their use contributes to process efficiency and reduces the risk of undesirable events.

Types of chromatography

In the oil and gas industry, the most commonly used chromatographic methods are liquid chromatography (HPLC) and gas chromatography (GC):

Gas chromatography (GC)

Gas chromatography (GC) is a method for separating, detecting, and analyzing gaseous samples, liquids, and volatile solids. It is one of the basic techniques in chemical analysis.

Common carrier gases include helium, nitrogen, hydrogen, and mixtures of argon and methane. The choice of gas depends on the sample and detector, with helium being the most commonly used.

The sample is introduced using an injector (manual or automatic), where it evaporates through a heated injection system, carried by the gas into the column (the injector converts the sample into a gaseous state and mixes it with the mobile phase). The injection site is heated to approximately 50°C above the boiling point of the least volatile component.

GC is applied in the petrochemical, pharmaceutical, environmental studies, clinical chemistry, food industries, etc.

High-performance liquid chromatography (HPLC)

HPLC is widely used to analyze crude oils, oil distillates, and commercial oil products. This chromatographic analysis of oil products includes the separation and identification by hydrocarbon group composition and the separation, identification, and quantification of targeted components.

Various types of HPLC include chromatographic columns with polar or non-polar stationary phases and ion-exchange columns, different mobile phase compositions, and detection systems that allow the analysis of samples with different physical and chemical properties, solubility, density, and polarity.

Application of chromatographs in quality control

Chromatographs play a key role in every step of the oil and gas production process:

Raw material control: Analysis of crude oil and natural gas to determine their composition and quality before further processing.

Process monitoring: Monitoring the refining and manufacturing processes to ensure products are up to specifications.

Final product quality control: Checking the quality of fuels, lubricants and other products before they are released to the market.

Integrated natural gas analysis solutions

Macel Plin, with over 22 years of experience in the industry, offers integrated solutions for the sampling and processing of gas fluids, setting the standard for precision and reliability.

ENCAL 3000

One of the products is ENCAL 3000, a gas chromatograph designed specifically for measuring the energy content of natural gas. This chromatograph uses state-of-the-art components to ensure accurate and reliable measurements of energy content, allowing for accurate quantification of natural gas components. Its compact, explosion-proof design ensures safe operation in all conditions.

A key advantage of the ENCAL 3000 chromatograph is its ability to maintain high standards of gas quality control. Regular maintenance and preventive and corrective maintenance are essential to ensuring measurement accuracy and reliability. Macel Plin provides comprehensive maintenance services for all its analyzers and chromatographs, ensuring optimal performance, reducing downtime, and extending device life.

In addition to ENCAL 3000, we offer other high-end chromatographs, such as Aurora and Oxy.IQ.

Aurora and Oxy.IQ

Aurora uses tunable diode laser absorption spectroscopy (TDLAS) technology to monitor the dew point in natural gas. This technology provides fast response and low operating costs, with no need for recalibration.

Oxy.IQ is a compact oxygen transporter that measures oxygen in ppm and percentage ranges. This device uses proven sensor technology to accurately measure oxygen in a variety of gases, even in hazardous environments.

By offering top-notch products and an experienced team of experts, Macel Plin continues to set the standard in natural gas analysis, providing reliability, precision, and expertise essential in this demanding industry area.

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