The cycle phenomenon is a major concern for oil and gas operators running carbon steel pipelines. Total Hazardous and Integrated Solutions has been refining its technology for the quick, efficient and effective decontamination of these pipes to keep mercury levels in check.
The oil and gas industry is aware of the cycle phenomenon, whereby mercury is absorbed into the surface matrix of carbon steel pipelines during the process and transportation of contaminated hydrocarbon mediums, and its subsequent ability to desorb from the steel surface and return to those same - or new, uncontaminated - streams. However, the fate of the pipeline itself falls under further complications, with lengthy, costly and typically unverifiable results.
As a growing concern among operators and companies around the world, the decommissioning, passivation and abandonment of contaminated subsea pipelines has always had its limits, and current legislation only deals with the decontamination of free (adsorbed) mercury from pipeline internals prior to its decommissioning.
While concerns remain high for the fate of carbon steel pipelines that have inevitably become contaminated during the transportation of mercury-contaminated hydrocarbon and produced water streams, viable solutions have been limited to costly and hazardous applications involving filling pipelines with acid or flushing them with hazardous lixiviant solutions. These procedures have varying rates of success, and there is very limited analytical data or in-situ analytical evidence to prove their effectiveness.
The latest developments in chemical and analytical technology to address this long-standing issue for the decontamination and reuse, or decommissioning and abandonment of subsea oil and gas pipelines when contaminated with mercury is one that Total Hazardous and Integrated Solutions (THIS) has been researching, testing and proving since its incorporation.
Taking chemical technology to the next step in order to apply it in an integral yet remote environment where efficacy and efficiency are key factors has been a huge undertaking - not only in terms of producing a chemical formula that can desorb mercury from the surface scale and its subsurface matrix, and take it into solution, but to be able to perform this task in minutes as opposed to the hours typically required for legacy techniques as well.
If a chemical can be applied in a short time frame and it is possible to reduce the total volume of chemical required using conventional methods, then costly decommissioning, demolition and removal become less of a requirement, and reuse and/or true passivation can be carried out.
While the mercury capture of the resultant solution can be analysed, this does not, however, provide evidence that the scope has been achieved - only of its partial success. The efficiency of the treatment chemical still has to be verified, and the inline technology to address this is currently in development.
However, chemical desorption and decontamination results are repeatedly showing decreases of <2%wwt mercury by as much as 90-95% in a single pass using a chemical batching pig train incorporating THIS chemical technology.
Other concerns for decommissioning and the fate of mercury-contaminated waste steel and ancillaries have already been proven by THIS with selected treatment solutions to rapidly desorb and decontaminate steel sections prior to hot work, or decontamination of tanks, vessels, valves, pumps, pig tools and other ancillaries for reuse or disposal.
Large-scale decontamination of refineries, process facilities, FSO/FPSO, offshore platforms and crude storage tanks is carried out effectively, quickly and safely, and is engineered to be very cost-effective.
The final piece of the puzzle is what happens to all that waste - mercury-contaminated steel pipes, hazardous waste chemicals and water solutions, as well as contaminated hydrocarbon sludge. That has also been addressed, and now the desorption and decontamination of carbon steel pipe sections can be treated for mercury levels <3%wwt down to 0ppm with a two-to-three-hour process that has now been engineered into a patent-pending mobile package to include full encapsulation and solidification of the fluid waste upon completion, in full compliance with TCLP non-hazardous disposal parameters.
