Full mercury decontamination of all exposed areas/parts can be achieved using a combination of thermal and kinetic technologies while incorporating a proprietary mercury vapour suppression and amalgam chemical formula.

Once a full surface decontamination has been carried out compliance is achieved by testing with both hand held XRF analysers and mercury vapour analysers.

Full non-destructive decontamination of all PIG components can be achieved quickly, safely and cost effectively using the latest in combined chemical and proprietary technology:

• Thermal Desorption Unit [TDU]
• Chemical & Steam Reflux System
• Peri-Vacuum Worktops
• HP Jet Nozzle Flushing Tank
• Dry Powder Bath

THIS can also provide certification for safe transportation of decontaminated materials from one country to another.

THIS is currently the only company in the world to hold proprietary chemical technology that has been independently proven to desorb and sequester mercury, not only from the pipe scale, but also from the sub-surface matrix of carbon steel substrate.

Performing full desorption and decontamination of mercury-contaminated waste steel and decommissioned pipe sections allows the steel to be recycled by smelter while the chemical waste can be reduced and stabilised for disposal in accordance with local regulations, as opposed to international disposal routes.

The efficacy of the MerCure chemical is further enhanced using a proprietary, closed-loop application which simplifies the process of pipe section decontamination, across any range of ID and lengths of up to 40ft.
The entire process is completed in a number of hours and the results are confirmed by hand held XRF analysis or samples can be cold cut for ICP-MS (or EDXRF) lab analysis.

The system is designed to be modular for use in remote locations and is setup and operated within a secondary containment area, for additional protection. Using this modular system makes it easy to up-scale the process in order to treat multiple sections of pipe simultaneously, while keeping manpower and logistics to a minimum.

Any carbon steel material that comes into contact with mercury-contaminated process gases or fluids will absorb mercury into its surface matrix, with the amount of mercury absorbed governed by various factors including (but not limited to) material composition, pressure, temperature, time, concentration, flow rate, etc.

Performing any type of manual ‘hot’ work such as welding, flame torch cutting, grinding, blasting and most other surface preparation is highly dangerous in a mercury-contaminated environment and exposure for personnel not correctly protected will result in acute exposure or possible fatality.

Any action that raises the temperature of the material above normal ambient will initiate the release of retained mercury to some degree. The vapourisation rate of elemental mercury doubles with every 10°C raise in temperature and the performance of any hot work on mercury-contaminated equipment or materials, is immediately dangerous to health and life of all personnel involved and must be managed carefully to ensure the safety of personnel.

Mercury when heated in the presence of air to a temperature above 300°C – 350°C. the mercury vapour will bond with oxygen in the atmosphere and convert to a mercuric oxide aerosol, which is highly toxic and can be lethal in high concentrations.

Normally hot work requires personnel to be in close proximity to the material being heated which increases the risk and providing personnel with the correct PPE is just part of the answer. Personnel deemed ‘At Risk’ must fully understand the environment they are working in, the changes that will occur, the increased dangers and exactly how the PPE is worn or applied.

THIS has highly trained and experienced personnel to perform works in these hazardous environments but can also provide consultancy and training on PPE, detection and monitoring systems, decontamination, containment and response.

The demolition and destruction of hazardous materials can be carried out pre or post decontamination depending upon the end scope, location of works, handling criteria and type of contamination. THIS recommends that waste process equipment, pipe and tanks are rendered ‘beyond use’, especially when they are destined for recycle or disposal to ensure they cannot be modified and repaired for use in water storage or other uses.

Ideally, prior to destruction, all vessels, valves, piping, etc., are fully decontaminated using a combination of technologies, optimised for the target contaminants and material being demolished including, but not limited to:

• Desorption chemistry
• Vapour suppressants
• Surfactants
• Thermal desorption
• Kinetic processes

Full PPE, monitoring equipment and Respiratory Protective Devices (RPD) are employed by operatives cutting contaminated steel into pre-determined sections, for safer handling, transportation and smelting purposes.

All staff are subjected to blood & urine analysis before and after tasks of this nature.

Full mercury decontamination of all accessible areas/parts can be achieved using a combination of proven techniques incorporating the latest chemical technology.

Systems can be flushed and/or chemically purged, depending on the unit’s limitations and sensitivities.

Where some equipment may have heat or pressure limitations these are addressed accordingly and care is taken to ensure there is full chemical compatibility with the treated unit.All components used by THIS to treat the units are designed to be universal to accommodate variations in sizes and connectivity.

Once a full surface decontamination has been carried out compliance is determined by testing with both hand held XRF analysers and mercury vapour analysers.

A range of skid units have been successfully decontaminated including:

• Wellhead Desander
• Blow Out Preventer (BOP)
• Gas Compressors
• Heater Treater
• Water Treatment Skid
• Hydraulic Pack
• Jet Fuel Tanks
• Pump Units

The presence of mercury in a lot of process systems is relatively easy to deal with during normal operations however the contact of mercury with sensitive systems is of serious concern and must be addressed correctly with preventative measures or removal systems.

Process system materials and alloys which are incompatible with mercury and have an interactive role may already pose a potential issue but other factors will increase that risk exponentially.

System materials such as aluminium are susceptible to aggressive degradation in the presence of mercury. If the aluminium oxide layer has become damaged, usually due to sand or other particulate matter impacting the surface, and the mercury comes into contact with the exposed substrate the reaction can lead to a potentially catastrophic incident as the system integrity becomes compromised.

Decontamination of these systems cannot be carried out using conventional chemical technology as most chemicals used to remove mercury with also react negatively with the same incompatible materials.

THIS uses a selection of specialist chemicals which can be used on these materials without damaging them while still being able to encapsulate the mercury or sequester it into solution and is effective for use in systems made of, or containing, aluminium, copper and brass components.

As effective as these chemicals are to remove traces of mercury it is still the recommendation of THIS that a 3rd party inspection, NDT and full integral check of the system and/or components is carried out prior to recommission.

Various offshore installations, vessels, tanks and process equipment can be rapidly decontaminated using a proven combination of select chemicals and an optimised application.

Whether a system is chemically flushed or manually decontaminated it is possible to desorb and decontaminate mercury from the surface and sub-surface matrix prior to inspection or maintenance works.

In particular, where hot work activities such as welding, grinding, cutting or grit blasting are required then mercury must be removed from the surface of the steel, prior to work starting. The surfaces can be fully decontaminated using a spray on application designed specifically to sequester mercury from the surface matrix, making it safe to continue.

A range of offshore systems have been successfully decontaminated including:

• Wellheads
• Process Vessels
• Free Water Knock-Out Tank
• MRU (Mercury Removal Unit)
• Metering Skids
• Storage Tanks
• Pipelines
• PIG Launcher/Receiver
• Glycol Systems
• Accommodation Units
• Subsea Piping
• Pumps & Valves

Most petrochemicals plants and refineries utilise available steam and nitrogen to purge the process equipment during shutdown and prior to maintenance works. However, these techniques require longer time periods and are ineffective where there are high levels of mercury present.

THIS experiences and track records have proven that by applying the appropriate decontamination chemicals, into the existing steam purge phase, will increase the performance capabilities of the purge and eliminate mercury from the system vapour spaces by stabilising it as a soluble salt.

Using specialty decontamination chemicals shortens this time considerably by a factor of hours, if not days, and helps to attain higher levels of safety for shutdown, maintenance and confined space entry works.

With less equipment and manpower than usual, the chemicals are designed to work against the contaminants rapidly and effectively to dramatically reduce down time.

THIS is currently the only company in the world to hold proprietary chemical technology that has been independently proven to desorb and sequester mercury, not only from the pipe scale, but also from the sub-surface matrix of carbon steel substrate.

THIS is in the process of proving how the MerCure chemistry can be applied, in various configurations, to enable subsea pipelines to be decontaminated while remaining in-situ. Verification has been carried out using lab analysis and workshop-based simulations, to the extent that after being witnessed by clients, is being further up-scaled to be run in a purpose built test facility before being put into full scale field trials with 2 (two) pipelines already determined for application.

The performance of the MerCure chemicals, for this particular application, is still in its infancy and further testing is to be carried out in order to optimise the application and address the variations expected within the target pipelines, but the benefits of using a controlled volume of chemical being applied as part of a ‘PIG Train’ instead of conventional methods or removal of the pipeline are overwhelming.

THIS remains confident that it has the solution to addressing the costly practice of pipeline removal, where it is required, when abandonment or reuse is not feasible due to mercury-contamination and has already had the PIG tool technology developed to ensure compatibility with the MerCure chemistry.

The resultant waste chemical can also be treated and reduced to meet compliance for reinjection or local disposal requirements.

As THIS continues their research into this solution we encourage you to contact us if you are interested in trialling the application or would like to be kept up to date on its development.