A major challenge for thermal oil sands producers is the final cleanup of the process contaminated water, so that it can be re-used for steam generation. Meeting produced water quality specifications is critical for reliable operation of water treatment and steam generation facilities.
Aker Solutions is an emerging supplier in this important market. We have applied our experience with oil-water separation and have introduced our own line of produced water clean-up technologies, using Induced Gas Flotation (IGF) technology. This broadens our heavy oil separation offering so that we can offer a complete oil treatment solution.
Induced gas flotation is a process which introduces small bubbles of gas, or air, into an oily water stream to accelerate the separation of the oil droplets from the water phase.
The small bubbles adhere to the small oil droplets, decrease the overall specific gravity of the oil droplets and result in a rapid rise of the oil droplets to the surface of the water. The oil droplets and gas bubbles accumulate on the surface in the form of an oily froth which is skimmed from the water surface, either by mechanical skimmers, or by an overflow type weir.
Several types of gasses can be used for gas flotation, including air, natural gas, nitrogen or carbon dioxide.
The free oil in water content of the effluent will vary depending on the operating conditions. Generally, it may be expected to run between 1 and 10%25 of the inlet oil concentration under normal operating conditions. Most IGF units work best with inlet oil concentrations ranging between 50 and 500 parts per million.
Aker Solutions IGF units are custom designed horizontal units with six cells or compartments; an inlet cell, four flotation cells, an outlet cell, and a skimmed oil cell. Our IGF units are hydraulic type units, where the gas bubbles are hydraulically introduced into the water stream via a recycle pump and eductors or by dissolving the gas into the water stream using a specially designed pump.