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Mercury in the Petrochemical Industry
Mercury occurs naturally in natural gas, coal and crude oil and it is through combustion of these fossil fuels that the majority of mercury is released into the environment. Once in the atmosphere mercury is deposited on land and sea, where it eventually enters the food chain in fish or shellfish.
The importance of mercury to the environment and the petrochemical industry cannot be overemphasised. From an environmental point of view it is highly toxic, causing severe damage to the human central nervous system; human exposure to mercury is mainly through diet, principally in the form of fish and shellfish. Mercury is bioaccumulated in fish with the result that larger predatory fish such as tuna generally have the highest levels of mercury. Mussels and other shellfish are filter feeders, which again results in preconcentration of mercury (and other contaminants) in their flesh.
Mercury is particularly problematic in the petrochemical industry; it forms amalgams with several metals, particularly aluminium, which leads to Liquid Metal Embrittlement (LME). This is prevelant on pipeline welds, cryogenic components, aluminium heat exchangers and hydrogenation catalysts. Failure of any of these components can lead to plant shutdown, with severe economic implications, or, in extreme cases, uncontrolled loss of containment or complete plant failure with catastrophic results. From a commercial point of view, products with higher mercury levels are deemed to be of a poorer quality, with the result that they command a lower price.
The ability to measure mercury accurately and act accordingly can have significant benefits to the efficiency of your process and therefore to your business.
Using state-of-the-art instrumentation and a team of specialised analysts, SGS have the experience to provide solutions for every mercury related application you may have, either on or off site. Whether the sample be natural gas, crude oil, naphtha, condensate, drinking water, waste water, soil, sediment or sludge (or virtually anything else), SGS have the knowledge and expertise to provide a solution.
Natural Gas
Mercury concentrations in natural gas can range from below 1ng m-3 to greater than 1000µg m-3 depending on the location, the well or the process. Mercury Removal Units (MRUs) are frequently utilised but their efficiency and lifetime must be monitored to ensure the specifications are being met.
Mercury in natural gas is measured using amalgamation atomic fluorescence spectrometry. A sampling system designed specifically for sampling natural gas for mercury is used to collect the sample on gold tubes, which are then analysed on an atomic fluorescence analyser. The sampling system is portable and rated for use in EExe IIC T3 areas, allowing it to be taken right to the sample point. The whole procedure is compliant with ISO 6978-2 and ASTM 6350.
How Can SGS Help You?
- SGS offer on and off site analysis of mercury in natural gas.
- Verify the efficiency of mercury removal units.
- Confirm the mercury concentration in gas being fed to aluminium heat exchangers.
- Carry out mercury mapping around your plant or process.
- Measure the mercury concentration in sales gas.
Light Hydrocarbon Liquids
Analysis of light hydrocarbon liquids can be extremely difficult due to the volatility of the sample; any sample pre-treatment can increase the possibility of losses and errors. Light naphtha samples can be analysed directly, without the need for any pre-treatment using preconcentration system in conjunction with an atomic fluorescence analyser. As sample handling is reduced to a minimum, losses due to evaporation are minimised, which is a huge advantage when dealing with such volatile samples.
SGS provide the solution for you:
- SGS can analyse your light hydrocarbons.
- Direct analysis - no losses through evaporation.
- Fast turnaround times.
- Excellent detection limits.
Crude Oil, Condensates, Soils, Sediments and Sludges
The mercury concentration in crude oil can range from sub ppb to thousands of ppm depending on the well and the location. This is of great importance as crude oil is the feedstock for many petrochemical applications. Samples are analysed using a dedicated mercury analyzer after acid extraction/digestion. Condensate and naphtha samples can also be analysed using this approach.
The SGS solution:
- Sample-specific wet chemical and microwave digestion procedures.
- Total mercury concentrations in a wide range of samples
- State-of-the-art mercury analysers.
- Excellent sensitivity, linearity and freedom from interferences.
- UKAS 17025 accredited laboratories.
Mercury Speciation Analysis
Mercury speciation analysis is vitally important tool when trying to gain an understanding of the transportation of mercury through a process. Different mercury species have different physiochemical properties and it is therefore of great importance to know what species are present when trying to optimise mercury removal strategies. SGS can help you with mercury speciation analysis to help gain a better understanding of how mercury is being transported through your process, and how to remove it.
What can SGS do for you?
- Mercury speciation/fractionation analysis.
- Various sample types aqeous, organic and solid samples.
- Contact SGS directly for further information.
Consultancy Services
SGS have a team of specialists offering a consultancy service, carrying out mercury surveys onsite, identifying areas of potential mercury contamination, areas of mercury loss and monitoring the efficiency of MRUs, helping to keep your process running efficiently.
Environmental Samples
Mercury concentrations in drinking, river or sea water are typically below 5ng l-1, making it extremely difficult to measure using many techniques. By using cold vapour atomic fluorescence spectrometry, which is compliant with BSI CEN 13506 and EPA 245.7, method detection limits of <1ng l-1 can be achieved, making the it possible. Waste water and produced water can also be analysed using the same approach. Fish and shellfish, which represent our main exposure to mercury as part of our diet, contain significant levels of mercury. These samples, along with soil, sediment or sludges can be analysed using cold vapour atomic fluorescence spectrometry.
How SGS can assist with your environmental samples:
- Analysis of drinking, river and wastewater samples.
- Analysis of soils, sediments and sludges.
- Analysis of fish and shellfish.
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