How to Ensure Precise Organic Chloride Measurements in Crude Oil and Naphtha with ISO 17034 CRMs

Cutting Refinery Costs: Leveraging ISO 17034-Certified CRMs for Accurate Chlorine Analysis in Petroleum Products

Accurate determination of chlorine content—especially organic chlorides—in petroleum products such as crude oil, naphtha, gasoline, diesel fuel, residual oil, and mineral oil is critical for refinery profitability and operational efficiency. Chlorine contamination can lead to severe equipment corrosion, catalyst poisoning, and non-compliance with stringent regulatory standards, all of which contribute to significant cost burdens. This brief blog post examines common sources of chlorine in crude oils and feedstocks, the impact of high chlorine levels on refining processes and product quality, industry-standard methods for chlorine determination, and how ISO 17034-certified reference materials (CRMs) deliver substantial cost savings by ensuring reliable, traceable chlorine measurements.

Sources of Chlorine Contamination in Crude Oils and Feedstocks

Though not naturally present in crude oil, chlorine can be introduced into crude and subsequent feedstocks through multiple pathways:

• Drilling and Production Fluids: Chloride ions are frequently present in drilling fluids and produced water. During extraction, salts and chlorinated compounds can contaminate the crude oil.
• Enhanced Oil Recovery (EOR) Operations: Techniques such as water flooding and chemical injection introduce chloride ions that persist in the crude.
• Processing and Storage: Exposure to chloride-containing water during transportation, storage, or preliminary processing—such as caustic washes or contact with residual brines—can further elevate chlorine levels.
• Chemical Additives: The inadvertent introduction of chlorinated solvents or other additives during maintenance or processing stages can contribute additional chlorine contaminants.

These sources not only increase the overall chlorine load but also add organic chlorides that decompose during refining to form corrosive hydrogen chloride (HCl), thereby impairing downstream operations.

Impact of High Chlorine Levels on Refining Processes and Product Quality

Equipment Corrosion and Process Disruption

During refining, organic chlorides decompose under high-temperature conditions to generate HCl. In the presence of moisture, HCl aggressively corrodes metal surfaces, leading to:

• Accelerated Degradation: Critical equipment such as distillation columns, condensers, and piping systems are rapidly corroded, necessitating more frequent maintenance and premature replacement. Naphtha Hydrotreaters are especially impacted. 
• Contaminant Leaching: Corrosion products can migrate into refined streams, diminishing product purity and complicating further processing. Introduction of iron possible. 

Catalyst Poisoning and Reduced Efficiency

Catalytic processes—including hydrotreating and reforming—are extremely sensitive to chlorine:

• Catalyst Deactivation: Even trace levels of chlorine can poison high-value catalysts (e.g., those based on platinum, palladium, or zeolite systems), reducing conversion efficiency.
• Shortened Catalyst Life: Frequent catalyst regeneration or replacement disrupts production continuity, increases hydrogen consumption, and elevates overall operating expenses.

Product Quality and Regulatory Compliance

High chlorine content is especially problematic in high-purity naphtha and petrochemical feedstocks:

• Rejected Shipments: Products that exceed established chlorine limits may be rejected, leading to logistical delays and revenue loss.
• Regulatory Fines and Penalties: Agencies such as the U.S. EPA, EU authorities, and the California Air Resources Board (CARB) enforce strict chlorine thresholds. Non-compliance can result in substantial fines and reputational damage.
• Adverse Impact on End-Use Applications: In processes such as polymerization or catalytic cracking, even minimal chlorine residues can adversely affect downstream product performance.

Industry Standard Methods for Chlorine Determination

Reliable chlorine quantification in petroleum products is achieved using several standardized analytical methods. The following key ASTM methods are widely accepted in both industry and regulatory frameworks:

ASTM D5808

• Description: This method employs high-temperature combustion followed by coulometric titration for the determination of organic chlorides.
• Applicable Matrix: Aromatic hydrocarbons. Primarily designed for light petroleum products such as gasoline and diesel fuels.
• Concentration Range: Applicable for chlorine concentrations from approximately 0.2 mg/kg (200 ppb) up to 25 mg/kg (25 ppm).

ASTM D4929

• Description: Focused on the determination of organic chlorine, this method uses high-temperature combustion coupled with micro coulometry in procedure B or using XRF utilizing procedure C. 
• Applicable Matrix: Suitable for a broad range of liquid hydrocarbons, including crude oil and naphtha fractions.
• Concentration Range: Above 1ug/g organically bound chlorine. 

ASTM D7536

• Description: Chlorine content of aromatics utilizing monochromatic WD-XRF
• Applicable Matrix: Aromatic hydrocarbons such as naphtha and gasoline
• Concentration Range: Limit of detection of 0.2 mg/kg up to 10 mg/kg. Higher chlorine content can be measured by diluting with a suitable solvent. 

These methods provide the foundation for accurate chlorine measurements; however, their effectiveness is critically dependent on using high-quality, traceable calibration standards.

The Role of ISO 17034-Certified Reference Materials

The reliability of analytical techniques—such as X-ray Fluorescence (XRF) and microcoulometry—is inherently linked to the quality of the calibration standards employed. ISO 17034-certified CRMs offer several essential benefits:

• Homogeneity and Stability: Rigorous testing ensures that the CRMs maintain consistent performance over extended periods.
• Traceability to SI Units: ASI Standards’ CRMs are fully traceable to NIST Standard Reference Materials (SRMs)
• Documented Uncertainty: Detailed uncertainty values accompany these CRMs, ensuring that high-precision measurements are defensible during regulatory audits and quality control assessments.
• Full Documentation: All orders come with a detailed certificate of analysis and safety data sheet.
• Rigorous Quality Assurance: ASI Standards' state of the art in-house laboratory tests each bottle according to an applicable industry method after manufacturing to guarantee quality. 

• Ensures Compliance with ISO 17025 Audits: Utilizing ISO 17034 CRMs helps laboratories maintain compliance with ISO 17025 standards for testing facilities. 

ASI Standards: Gravimetrically Prepared Calibration and QC Check Standards

ASI Standards provides a comprehensive suite of gravimetrically prepared calibration and quality control (QC) check standards for chlorine across various petroleum matrices, including:

• Mineral Oil
• Crude Oil
• Gasoline
• Diesel Fuel
• Isooctane
• Toluene
• Xylenes
• Residual Oil
• Fuel Oil

These standards are fully customizable, with chlorine concentration ranges adjustable from less than 1 mg/kg (1 ppm) up to weight percent levels. This versatility ensures that they meet the specific analytical requirements of any refining process. With full traceability to NIST SRMs, ASI Standards’ CRMs deliver the metrological accuracy necessary for optimal process control, catalyst and corrosion protection, and strict regulatory compliance.

Calibration sets and QC check standards are matrix matched to your unknown samples to ensure the most accurate analysis by removing spectral interferences, differences in density, and differing C/H ratios. 

Chlorine standards can also be combined with nitrogen or sulfur in the same standard for measuring multiple analytes.

Economic Benefits and Cost Savings

Accurate chlorine measurement directly translates into significant cost savings for refineries by reducing the likelihood of costly unplanned maintenance and process inefficiencies:

• Reduced Downtime: Precise data prevent premature equipment failures due to corrosion, helping refineries avoid production losses that can reach up to $1M per day.
• Extended Catalyst Life: Preventing chlorine-induced catalyst poisoning maintains catalyst performance and reduces replacement costs, which can range from $20,000 to $100,000 per ton.
• Optimized Process Efficiency: Reliable chlorine measurements enable fine-tuning of desalting and hydro processing operations, thereby reducing unnecessary chemical usage and energy consumption.
• Regulatory Compliance: High-precision, traceable measurements minimize the risk of non-compliance penalties, safeguarding the refinery’s market position and reputation.

Conclusion

Chlorine contamination in petroleum refining presents a multifaceted challenge that significantly impacts equipment integrity, catalyst performance, and product quality. Inaccurate chlorine measurements can lead to costly unplanned maintenance, reduced catalyst lifespans, and substantial regulatory penalties. By leveraging ISO 17034-certified CRMs from ASI Standards, refineries can achieve precise, reproducible, and traceable chlorine analysis that optimizes processing operations and delivers substantial cost savings.

For refineries dedicated to protecting critical assets, enhancing process efficiency, and ensuring strict regulatory compliance, investing in high-quality, gravimetrically prepared chlorine calibration and QC check standards is a strategic imperative.

Contact ASI Standards today to learn how customizable, NIST-traceable chlorine CRMs can elevate your analytical capabilities and drive significant cost savings in your refining operations.

ASI's wide range of calibration sets and QC check standards for chlorine can be found on our convenient online shop. Click here to view our offerings and buy direct or fill out the form below for a custom quote!