Membrane distillation to cut costs in oil industry

Membrane distillation (MD), a thermally-driven separation process, is a promising technology for desalting highly saline waters.

According to researchers at the Masdar Institute of Science and Technoolgy, oil producers and petroleum refineries could save up to $50 billion if membrane distillation techniques are applied to treatment of produced water.

Produced water constitutes one of the largest wastewater streams generated in the petroleum industry

Dr Nidal Hilal said: “Treatment of produced water is a huge challenge faced by the petroleum industry. Current options include discharge into the environment, or re-injection into disposal wells.

“But environmental regulations strictly govern such measures. Also, exorbitant cost of available technologies and their low efficiency levels plague the scenario. The membrane distillation offers the right solution.”

Produced water constitutes one of the largest wastewater streams generated in the petroleum industry.

The Masdar Institute estimates that a minimum of three barrels of produced water comes out with every barrel of oil, which totaled more than 145 billion barrels in 2011 alone.

The total dissolved solids (TDS) can reach up to 200,000 ppm which is around five times the TDS in seawater.

The group has recently written a paper titled ‘Produced water treatment: Application of Air Gap Membrane Distillation’ arguing the case for the technology.

The paper notes that current practices of produced water management in the petroleum industry do not ensure the rate of natural water replenishment required to balance the colossal water consumption by the industry.

While water resource sustainability concerns suggest maximal reuse and recycling of water, traditional methods of produced water management are largely inadequate in treating produced water up to discharge and reuse standards.

The Masdar researchers note MD requires significantly lower operating temperatures and therefore lower energy requirements.

Since non-volatile solutes cannot be transported across the membrane barrier in an MD system, it is capable of achieving near 100% rejection of dissolved salts and minerals.