Water Clarifiers Deoilers - Chemicals Services
Demulsification and separation of the hydrocarbon phase during Primary separation of produced fluids does not usually leave an aqueous phase sufficiently free of hydrocarbons to meet the discharge limits required for water disposal. Depending on the geographic location, these limits can be from 40 ppm residual oil in water, to as low as 10 ppm. Environmental regulations will continue to press for reduction of these discharge limits, particularly in marine environments.
Typically, a separation system will have equipment for treating the waste water to encourage the further separation of the oil droplets from the water; this equipment includes hydro cyclones, flotation tanks, filtration units, and centrifuges; the performance of these devices can be significantly improved through the use of chemical flocculating agents.
The flocculants are referred to interchangeably as deoilers (due to the removal of the oil) or water clarifiers (due to improvement in water quality). The emulsion droplets that have not been removed by the primary separating system will be significantly stabilized from further coalescence due to two mechanisms; the first is mutual charge repulsion of emulsion droplets.
As fluids are processed, the decreasing pressure allows the PH of the water to rise, resulting in the deprotonation of naturally occurring fatty and naphthenic acids present in the crude; these salts provide a negative charge to the emulsion surface and actually repel other oil droplets that would coalesce upon interaction.
In high TDS brines, calcium soaps of fatty/ naphthenic acids can form, creating a solid phase at the water interface, making coalescence even slower. This is similar to the second stabilizing mechanism where by organic and/or inorganic solids adsorb to the emulsion oil/water interface, effectively sealing it from exposure to other emulsion droplets and impeding the coalescence mechanism. If the emulsion droplets are sufficiently small, Brownian motion will keep the emulsion stable indefinitely.
Effective defiling can be achieved using polyelectrolytes that encourage flocculation of the emulsion droplets into larger collections, which are then more readily acted upon by the physical separation equipment in the water treatment process. The preferred polymers neutralize the repulsive charges developed on the emulsion droplets, and if of sufficient size, can also bridge between the droplets collecting then together into flocculated groups where coalescence may occur due to close proximity. Flocculants are designed to function in the high salinity brims.
SAPESCO products include a range of natural and synthetic materials to meet the performance and environmental needs of the market.
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