An Innovative Zero-Liquid Discharge Intermediate-Cold-Liquid Eutectic-Freeze Desalination System
The oil and gas industry produces a massive amount of water from underground reservoirs through its wells. Approximately 9 barrels of water is produced for every barrel of oil, and it is typically contaminated with a variety of minerals, heavy metals, and organic compounds. Freeze-desalination processes are well suited for these situations because pure ice crystals can be produced even in highly concentrated brine. However, current freeze-desalination technologies have various deficiencies that hinder their widespread use. At the same time, waste water management is a challenge for many municipalities and the agricultural sector. A primary consumer of increasingly scarce freshwater, this sector accounts for 63% of U.S. surface water withdrawals, according to the U.S. Geological Survey.
Project Innovation + Advantages:
The University of Oklahoma will develop a novel, zero-liquid discharge freeze system to remove dissolved salt from contaminated water, such as is produced by industrial processes like oil and gas extraction. The project will take advantage of the density difference between water and ice to extract pure ice from a salty brine, using a cooling approach that maximizes efficiency and avoids the need for energy-intensive evaporation methods. The system will operate under atmospheric pressure and be capable of treating highly concentrated/contaminated water. If successful, the treated water would be suitable for agricultural use, providing an abundant new water source and easing competition for this vital resource.
This project’s goal is develop a zero-liquid discharge (ZLD) freeze-desalination system capable of treating water with total dissolved solids (TDS) values up to 250,000 milligrams mg/L or milligrams per liter. (Seawater TDS are approximately 35,000 mg/L).
The proposed system offers a sustainable solution for the increasing water demand in industrial and oil and gas sectors by recycling the otherwise wasted water, without putting pressure on increasingly scarce fresh water resources also in demand by local communities for agricultural and municipal purposes.
The environmental concerns related to disposing highly contaminated water are avoided by the use of the proposed ZLD desalination system.
The goal is a levelized cost of water of $1.2/m3 for relatively small-scale desalination unit with a capacity of ≈1000 m3/day, well below the DOE target value of $1.5/m3 for ZLD desalination systems.