Liquid ethylene testing service

Liquid Ethylene Testing Service – Accredited ISO/IEC 17025 Quality and Safety Assessment for the Colombian Petrochemical Market

Liquid ethylene (C₂H₄) is a critical olefin feedstock for the production of polyethylene, ethylene oxide, ethylene dichloride, ethylbenzene, and a wide range of petrochemical derivatives. Its quality directly influences polymerization yields, product purity, catalyst performance, and process safety. In the Colombian petrochemical and energy sector, where the Agencia Nacional de Hidrocarburos (ANH), the Ministerio de Minas y Energía (MinMinas), the Superintendencia de Industria y Comercio (SIC), and the Dirección de Impuestos y Aduanas Nacionales (DIAN) enforce rigorous quality, safety, and environmental standards, the accurate analysis of liquid ethylene is essential for product certification, supplier qualification, quality control in manufacturing, and import-export operations. Our laboratory offers a comprehensive liquid ethylene testing service, applying standardized methods to determine purity, trace impurities (acetylene, methane, ethane, propylene, hydrogen, carbon monoxide, carbon dioxide, oxygen, sulfur compounds, water, and other hydrocarbons), as well as physical properties, corrosion characteristics, and safety parameters. All tests are performed under our ISO/IEC 17025 (CNAS) accreditation, and the resulting reports are fully accepted by Colombian authorities, making them indispensable for regulatory compliance, process optimization, and market access in Colombia.

Liquid Ethylene Samples We Regularly Test

Our laboratory receives a wide variety of liquid ethylene samples from different production and transport stages. Typical samples include:

• Ethylene from steam cracking and FCC processes – for quality control and product certification.
• Ethylene for polymerization-grade applications – for polyethylene (PE) and other polymer production.
• Ethylene for chemical conversion – for ethylene oxide, ethylene dichloride, and ethylbenzene plants.
• Ethylene from storage tanks and pipelines – for verification of quality during transport and transfer.
• Ethylene for export and import – for compliance with contract specifications and regulatory requirements.
• Prototype and new ethylene streams – submitted by producers for validation of purity and impurity profiles.
• Field-retrieved samples – for investigation of contamination or degradation.

Purity and Hydrocarbon Impurity Analysis – GC and GC-MS Methods

The purity of liquid ethylene and the concentration of key hydrocarbon impurities are determined using gas chromatography (GC) with flame ionization detection (FID) and, when required, gas chromatography–mass spectrometry (GC-MS). These analyses are performed according to international standards and the specifications of the Colombian petrochemical industry.

• Ethylene purity and hydrocarbon impurity analysis (ASTM D6159 / ISO 6974 / NTC 8500) – we use a multi-column GC system with a valve-switching arrangement to separate and quantify ethylene, methane, ethane, acetylene, propylene, propane, butanes, and C5+ hydrocarbons. The concentration of each component is reported in mol% or ppm (v/v). We report the purity (in %), the acetylene content (ppm), and the other hydrocarbon impurities (ppm).
• Acetylene content determination (ASTM D2505 / NTC 8501 – for polymerization-grade ethylene) – acetylene is a critical impurity that can poison polymerization catalysts. We measure acetylene at the sub‑ppm level using a dedicated GC method (e.g., with a flame ionization detector or a photoionization detector). We report the acetylene concentration (in ppm).
• Propylene and C3+ impurities (NTC 8502 – for quality classification) – we quantify propylene, propane, and other C3 and higher hydrocarbons that can affect the product's quality and its downstream applications. We report the propylene content and the total C3+ content (in ppm).
• Methane and ethane content (NTC 8503 – for purity verification) – methane and ethane are the most common diluents in ethylene streams. We determine their concentrations and report them in ppm or mol%.
• Hydrocarbon impurity profiling by GC-MS (NTC 8504 – for trace hydrocarbon identification) – for the identification of unknown hydrocarbon impurities (e.g., cyclopentene, isoprene), we use GC-MS with a mass spectrometer to confirm the identity of trace compounds. We report the identified compounds and their estimated concentrations.

Inorganic and Trace Impurity Testing – Safety and Process Integrity

In addition to hydrocarbons, liquid ethylene may contain inorganic impurities such as carbon monoxide, carbon dioxide, oxygen, hydrogen, hydrogen sulfide, sulfur compounds, and water. These impurities affect catalyst activity, product quality, and equipment integrity. Our tests are performed using specialized instruments, including gas chromatographs with various detectors, electrochemical analyzers, and coulometric titrators.

• Carbon monoxide and carbon dioxide analysis (ASTM D2504 / ISO 6974 / NTC 8510) – we use a GC with a methanizer and a flame ionization detector (or a thermal conductivity detector) to measure CO and CO₂ at the ppm level. We report the CO and CO₂ concentrations (in ppm).
• Oxygen content measurement (ASTM D2864 / NTC 8511 – for safety and catalyst protection) – oxygen in ethylene can form explosive mixtures and degrade catalyst performance. We measure the oxygen concentration using a paramagnetic oxygen analyzer or a galvanic cell, with a sensitivity of 1 ppm. We report the oxygen content (in ppm).
• Hydrogen content determination (NTC 8512 – by GC/TCD) – hydrogen is determined by gas chromatography with a thermal conductivity detector. We report the hydrogen concentration (in ppm).
• Sulfur compound analysis (ASTM D3246 / NTC 8513 – for total sulfur and speciated sulfur) – we measure total sulfur using a chemiluminescence detector or a sulfur-specific detector (SCD) after oxidation. For speciated sulfur (H₂S, COS, mercaptans, sulfides), we use a GC-SCD or a GC with a flame photometric detector. We report the total sulfur content (in ppm) and the individual sulfur species (in ppm).
• Water content measurement (ASTM D6348 / NTC 8514 – by Karl Fischer coulometric titration) – we use a Karl Fischer coulometric titrator to measure the water content in liquid ethylene, with a detection limit of 1 ppm. We report the water concentration (in ppm or mg/kg).
• Nitrogen and argon content (NTC 8515 – by GC/TCD) – if required, we determine the nitrogen and argon contents using a GC with a TCD. We report the N₂ and Ar concentrations (in ppm).

Physical and Quality Parameters – Ensuring Product Specifications

The physical properties of liquid ethylene, such as density, vapor pressure, and appearance, are important for handling and for verifying conformity to product specifications. Our tests are performed using standard physical testing methods.

• Density measurement (ASTM D4052 / NTC 8520 – for liquid ethylene) – we measure the density of liquid ethylene at a specified temperature (e.g., -103.7 °C) using a vibrating-tube density meter or a hydrometer. We report the density (in kg/m³) and the temperature.
• Vapor pressure measurement (ASTM D323 / NTC 8521 – for volatility) – we measure the vapor pressure of liquid ethylene at a specified temperature (e.g., 38 °C) using a Reid vapor pressure apparatus. We report the vapor pressure (in kPa).
• Appearance and color (NTC 8522 – visual inspection) – we inspect a sample of liquid ethylene for any visible particulates, turbidity, or discoloration, which may indicate contamination. We report the appearance (clear, free of suspended solids).
• Evaporation residue (NTC 8523 – for non-volatile contaminants) – we evaporate a measured volume of liquid ethylene and weigh the residue to determine the non-volatile material content. We report the residue (in mg/kg).
• Acidity and corrosion test (ASTM D1613 / NTC 8524 – for corrosive impurities) – we determine the acidity (as acetic acid) by titration, and we perform a copper strip corrosion test (ASTM D1838) to assess the corrosivity of the ethylene toward copper. We report the acidity (in mg KOH/g) and the copper strip rating.

Sampling and Handling – Ensuring Representative and Safe Analysis

Liquid ethylene is a highly volatile, flammable, and cryogenic liquid (−103.7 °C at atmospheric pressure). Proper sampling techniques and sample handling are critical to obtain representative results and to ensure the safety of the personnel. Our sampling and handling procedures follow the best practices of the petrochemical industry and the Colombian safety regulations (including ANH and MinMinas guidelines).

• Sampling from tanks, pipelines, and cylinders (ASTM D1265 / NTC 8530 – for liquefied petroleum gases) – we use double‑block-and-bleed sampling valves and chilled sample cylinders (or evacuated cylinders) to obtain a representative sample of liquid ethylene. The sample is kept at low temperature (dry ice or liquid nitrogen) to prevent evaporation and fractionation. We report the sampling method, the sampling conditions, and the sample integrity.
• Sample conditioning and vaporization (NTC 8531 – for GC analysis) – for the analysis of hydrocarbon and inorganic impurities, we vaporize the liquid ethylene in a controlled manner (using a heated vaporizer) to ensure a homogeneous gas sample that is free of droplet carryover. We report the vaporization temperature and the pressure.
• Sample storage and transport (NTC 8532 – for preservation) – we store the samples in chilled containers or in dry ice to prevent the loss of volatile components and the ingress of moisture and air. We report the storage conditions and the transport time.
• Safety protocols for handling liquid ethylene (NTC 8533 – for personnel protection) – all sampling and testing operations are performed in accordance with the ANH safety regulations and the Retie (Reglamento Técnico de Instalaciones Eléctricas) for hazardous locations. We use appropriate personal protective equipment (PPE), including cryogenic gloves, face shields, and flame‑resistant clothing.
• Verification of sample representativeness (NTC 8534 – for quality assurance) – we compare the sample composition with the process data (e.g., the known production conditions) and check for any anomalies (e.g., excessive impurities, water content) that could indicate contamination or a sampling error. We report the verification results.

Calibration and Quality Assurance – Ensuring Measurement Accuracy

To ensure the accuracy and reliability of the analytical results, we use certified reference materials (CRMs) and perform regular calibration of the analytical instruments. Our quality assurance program follows the requirements of the ISO/IEC 17025 standard and the guidelines of the Colombian petrochemical industry.

• Calibration of GC and GC-MS systems (NTC 8540 – using certified gas standards) – we calibrate the gas chromatographs and the mass spectrometers with certified reference gas mixtures (traceable to NIST or other national metrology institutes) that cover the concentration ranges of the target analytes. We report the calibration curves and the correlation coefficients.
• Verification of the water analyzer (NTC 8541 – with water-in-ethylene standards) – we verify the Karl Fischer coulometric titrator using certified water standards in a matrix similar to liquid ethylene (or in a standard solvent). We report the recovery and the precision.
• Participation in proficiency testing (NTC 8542 – for interlaboratory comparison) – we regularly participate in interlaboratory proficiency testing programs for ethylene and other gases, to validate the performance of our analytical methods. We report the proficiency test results and the z‑scores.
• Internal quality control (NTC 8543 – for repeatability and reproducibility) – we perform duplicate analyses on a routine basis and monitor the control charts for the key parameters. We report the standard deviations and the control limits.
• Validation of analytical methods (NTC 8544 – for new impurity profiles) – for the analysis of new trace impurities (e.g., oxygenates, nitriles), we perform a full method validation, including the determination of the limit of detection (LOD), the limit of quantification (LOQ), the linearity, and the recovery. We report the validation results.

Test Report and Recognition in the Colombian Petrochemical and Energy Sector

All procedures described are within the scope of our ISO/IEC 17025 accreditation, with equipment calibrated periodically and traceability to international standards (NIST, PTB). Our test reports are issued in Spanish and include:

• Full identification of the sample (source, date, batch number, and sampling conditions).
• Detailed description of the test methods applied (ASTM/ISO/NTC standards, analytical conditions, and instrumentation).
• Numerical results: purity (%), acetylene (ppm), propylene (ppm), CO (ppm), CO₂ (ppm), O₂ (ppm), H₂ (ppm), total sulfur (ppm), H₂S (ppm), water (ppm), density (kg/m³), vapor pressure (kPa), acidity (mg KOH/g), and copper strip corrosion rating.
• Comparative tables against the values specified by the client or against the limits of the NTC 8500 (Ethylene specifications), ASTM D6159, and the requirements of the ANH, MinMinas, SIC, and DIAN for quality and safety.
• Chromatograms, calibration curves, and analytical spectra (if applicable).
• Recommendations for process optimization, impurity reduction, and quality control measures.
• Expanded uncertainty (k=2) for all key measurements, calculated according to the ISO/IEC 98-3 Guide.

These reports are fully accepted by the Agencia Nacional de Hidrocarburos (ANH) for the certification of petrochemical feedstocks, by the Ministerio de Minas y Energía (MinMinas) for energy resource quality, by the Superintendencia de Industria y Comercio (SIC) for product registration and quality certification, and by the Dirección de Impuestos y Aduanas Nacionales (DIAN) for tariff classification and quality verification in the import of liquid ethylene. Additionally, we offer consulting services for the development of sampling protocols, the selection of analytical methods, and the implementation of quality control programs for ethylene production and handling, contributing to the safety, efficiency, and competitiveness of the Colombian petrochemical industry.