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PE Series

What is PE-Series?

Mercury naturally exists in crude oil with concentrations ranging from parts-per-billion (ppb) to parts-per-million (ppm), depending on its oil field location. Monitoring the concentration of mercury in crude oil before refinery processing is critical.

Mercury level in the feeds must be lower than the permittable threshold value to avoid accumulation of mercury within the refinery plant which causes Liquid Metal Embrittlement (LME). The phenomenon of LME compromises the structure of the refinery processes and will cause catastrophic consequences to the plant and jeopardize the safety of the workers.

NIC PE-series is designed to perform direct mercury measurement in liquid petroleum-based samples such as crude oil, condensate, naphtha, and the rest of its refined liquid fractions.

Operating Principle at A Glance

Septum-sealed Vial

The liquid petroleum-based sample is put into a 2 mL septum-sealed sample vial. Vortex-mixing effect can be applied to the sample to ensure homogeneity of the sample prior to sampling for analysis.

Direct Thermal Decomposition

The auto-liquid injector which draws the sample aliquot precisely to inject into a pyrolysis chamber to combust the hydrocarbons and decompose the mercury.

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Gold amalgamation

The decomposed mercury is then trapped, purified and concentrated onto the mercury collector tube, while interfering compounds are removed.

CVAFS Measurement

Purified mercury is desorbed and transported by argon into the optical cell of CVAFS in PE-Series for measurement.

Mercury in Liquid Hydrocarbon

Liquid hydrocarbon

  • Consists of a vast range of varieties ranging from heavy and viscous crude oil to highly volatile naphtha.
  • Feedstocks and its refined products have distinctive physical and chemical properties, which give rise to the challenge of analyzing this range of products in a same instrument.


  • Naturally occurring element, present in virtually all oil and gas, regardless is as raw feed or refined products. 
  • Mercury levels in crude oil and natural gas can vary widely, both between and within reservoirs (wells) and geographical regions.
  • Concentrations can be from low ppb (parts-per-billion) to low ppm (parts-per-million) levels.

Why is it important to measure Mercury in Liquid Hydrocarbon?

Mercury is a naturally occurring element, present in virtually all oil and gas, regardless is as raw feed or refined products. Mercury levels in crude oil and natural gas can vary widely, both between and within reservoirs (wells) and geographical regions. Concentrations can be from low ppb (parts-per-billion) to low ppm (parts-per-million) levels.

Mercury is not an ingredient in oil and gas, but a contaminant that can cause:

Potential LME

Implicating detrimental effect to the processing plant through amalgamation on metal surfaces

Catalyst Poisoning

Affecting the performance of the processing plant

Work Health & Safety

Create potential work hazard and accidents due to compromised plant structure from LME

Trading value

Impurities in Oil/Gas products affect its trading value

Therefore, in the oil and gas industries, Mercury is one of the critical measuring parameters on its feeds (crude oil or natural gas) to its products like propane, butane, naphtha, gasoline jet fuel, and more.

Challenges in Analyzing Mercury in Liquid Hydrocarbon – The Inconsistency

Oil refineries

Applications of PE-Series

PE-Series mercury analyzer can be used to analyze:

Talk to Us about your applications.

Industries & Application

Challenges In Analyzing Mercury in Liquid Hydrocarbon – The Inconsistency

Liquid hydrocarbons are highly flammable, varying widely in viscosity, flashing point, boiling point, specific gravity, etc. As for Mercury, its properties are unlike other heavy metals, and Mercury has a relatively higher vapor pressure. Thus it is highly volatile. It is always an analytical challenge to analyze Mercury in different liquid hydrocarbon products.

Crude oil

  • contains mostly of heavy hydrocarbon chains.
  • Thus, to analyze mercury in crude oil, the analyzer must be able to crack or break down all components, extracting only mercury from it.

How to ensure accurate analysis of Crude oil?

A precise and high enough temperature (typically 800oC or more) control is required to decompose all heavy hydrocarbons to ensure complete combustion, turning all hydrocarbons into COand H2O.

What happens if the combustion temperature is not sufficient?

Insufficient temperature causes incomplete combustion, forming carbon soot that accumulates within the analyzer over time. Carbon has absorptivity to mercury, thus causing memory-effect and inconsistency in the analysis results.


  • The lightest liquid fraction refined from crude oil distillation.
  • Mostly composed of mixtures that have 5~12 carbons, with the light cut boiling point ranging from 35~130℃; while boiling point of 130~220℃ for the heavier and aromatic cuts.
  • One of the highly valued and demand products, supplying as a feedstock to the petrochemical industry.
  • The feedstock naphtha is first hydrotreated before transferred to the catalytic reforming unit. The catalysts are made of precious metals which are sensitive to mercury and poisoning. Thus, the petrochemical processes have stringent controls on the mercury content in the feedstocks down to low single-digit parts-per-billion (ppb), preventing any foreseen detrimental effect to their process.

How to ensure accurate analysis of Naphtha?

  • Accurate sample volume transfer for all analytical measurements is important since result concentration is directly related to volume.
  • Sample integrity is extremely crucial. One has to prevent loss of analytes (including mercury) from its volatility and analyze the sample in a quick and precise manner to ensure minimum error.

In PE Series, sample transfer technique by direct syringe injection ensures sample volume is well-contained from aspiration to injection into the pyrolysis chamber, all within a closed loop where the sample is never left exposed to the atmosphere.

What happens when sample transfer is not done in a closed loop?

Compared to other techniques utilizing an open-concept holder, where the introduced samples are left to queue needlessly in the autosampler for analysis. With no assurance of sample integrity due to volatilization, results possibly will be compromised.