The design and construction of the counter-current advance reverse osmosis system have been completed.

April 2, 2021. Seville, Spain

The design of a counter-current advance reverse osmosis prototype in which a pre-commercial semi-permeable membrane developed by the prestigious manufacturer Toray (FO4040 model) is insalled have been completed. This membrane will be tested through counter-current flows to perform a non-convencional reverse osmosis process. In contrast with traditional seawater reverse osmosis systems, in this process two streams are entering into the pressure vessel, achieving the mass transfer by a possitive Net Driving Pressure. The two streams features are: i) seawater salinity (or similar salinity) and ii) brine or considerably higher salinity than the typical values of seawater.
The operating pressure should be higher than the osmotic pressure generated between these counter-current streams, transfering freshwater (solvent) from the higher salts (solute) concentration side to the lower satls concentration side. As a result of the process, a higher concentrated brine and a lower concentrated seawater are obtained. To reach a possitive Net Driving Pressure, the prototype includes a high pressure pump (fed by a precious circulantion pump) which increases the higher salinity stream pressure giving rise to the reverse osmosis process under determined conditions.

Figure 1

Stream 1-2: Pressurised brine stream (up to 25-30 bar, depending of the stream 3-4 salinity), which gives up a certain freshwater, resulting in a higher concentration brine.
Stream 3-4: Seawater stream (or brackish water) which is diluted by the absorption of freshwater from the stream 1-2.

A more detailed Piping and Instrumentation Diagram can be found hereby:

Figure 2