Eco-Tec Recoflo® Produced Water Softening System

Heavy oil deposits require "Enhanced Oil Recovery" techniques to improve their yield. Wells can be flooded with steam to loosen and lift the oil. This method typically produces 2-3 gallons of water for every gallon of heavy oil. "Produced water" can be discarded in abandoned wells, however, this is seldom practical due to the large quantities of make-up water required. Produced water can be used as make-up if a series of treatment steps are employed:

• oil removal (skimming, induced gas flotation, filtration)
• softening (hot or warm lime)
• silica removal (magnesium oxide treatment)
• softening (ion exchange)

A typical site can generate 8,000-16,000 m3/day (1,500-3,000 USGPM) of produced water with the following characteristics:

• 2,000-12,000 mg/L Total Dissolved Solids (TDS as CaCO3)
• 20-90 mg/L Total Hardness (TH as CaCO3)
• 100 mg/L Total Organic Carbon (TOC)
• Up to 95°C

A deep bed (standard) softening system for a typical site might include:

• 8-12 resin columns measuring 3.6m (12 ft.) diameter x 4.0m (13 ft.) high,
• regeneration skids and neutralization tanks.

To reduce water hardness to less than 0.2 ppm (and avoid boiler scaling), deep bed softeners use acid and caustic regenerations. To allow in-situ regeneration, produced water is cooled to 60-70°C. If cooling is not possible, resin must be removed from the column for regeneration in a separate vessel.

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