Production • Processing • Handling
Separating chemical emulsions to below 5 ppm
Reliably polishing slop water and produced water now comes as a robust, skid mounted solution, Paul Schouten and Eric Wals report.
now comes as a robust, skid mounted solution. TwinZapp technology consists of a two-step
T process:
● Te emulsions are destabilised through an oxidisation process.
● Te resulting neutrally buoyant particles are separated with a back-washable deep filtration system.
Emulsions in produced formation water are a given as corrosion inhibitors and other chemicals are injected. On drilling rigs, high amounts of slop water are generated while cleaning pits and decks. Te emulsions are often too strong to simply let gravity and time do its job. Space and time are exactly two major constraints in an offshore environment. Another constraint is manpower. Twin Filter and Brilliant Water Solutions have
developed a DNV and ATEX Zone II certified skid which operates independent of ongoing processes. No re-engineering is required. Te skid is simply a last step add-on before water is discharged and treats the water continuously at a typical rate of 30 bbl per hour.
Te emulsified water is first subjected to a mild,
well controlled, electrical oxidation process. Release of reactive oxygen, hydroxyl and other radicals destabilise the present surface active components. Te resulting free oil along with the neutrally buoyant particles (and associated oil) as well as a sizeable fraction of the dissolved aromatics is then removed by a fully re-generable filter at the final polishing stage.
Treatment Current technology mostly comes with drawbacks that in an offshore environment have serious consequences. New separation equipment is installed onto
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he last separation step for emulsified water is now possible without consumables and without the need for specialised personnel. Reliably polishing wastewater to below discharge limits
older platforms as the discharge limits become more stringent. An increasing water cut in production or a change in the chemical mix often results in a cycle of readjusting separation processes or an acceptance that volumes are sent to shore at high logistics and treatment cost. Hydro cyclones are limited to larger particle sizes, absorption media foul up and create logistics and waste problems of their own.
Fig. 1. From 1,900 to 900 to 10ppm.
On a drilling rig there is mostly no standard separation equipment to deal with emulsified water since this is only required at particular stages: after an oil based mud placement or when a well is cleaned up or lifted. A solution needs to be mobile and at best require no additional personnel. Te TwinZapp technology is supplied fully automatic in very compact skidmounted packages and can be installed in existing separation packages.
Test results
Te technology was developed and tested offshore through 2011. Tests with two major operators on several platforms with emulsified produced water
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