Thermal desalination won’t be killed off by RO membranes, says IDE Technologies

Although reverse osmosis (RO) membranes have developed to provide nearly 60% of worldwide desalinated water, there remains a large demand for thermal processes despite predictions the technology use will shrink, an industry expert has said.

In an exclusive interview with WWi magazine, IDE Technologies CEO and president Avshalom Felber said: “Firstly, people have been talking about thermal desalination disappearing for many years and it hasn’t yet. While it’s diminishing all the time, there is still a place for thermal solutions.”

IDE Technologies CEO said the company has invested more into its R&D division for thermal than RO desalination over the years.

Thermal desalination processes such as MSF (multi-stage flash) and MED (multiple effect distillation) have in the past provided the majority of potable water in regions such as the Middle East, where excess heat from power plants is used to heat and desalinate seawater.

Avshalom Felber, CEO of IDE Technologies, told WWi magazine that thermal desalination processes still have a lot of potential

Although thermal processes have been viewed as more robust in such regions, the decreasing cost of membranes has meant that seawater reverse osmosis (SWRO) processes have gained traction. Yet, outside of the Middle East, an ongoing discussion is whether RO processes will eventually fully replace thermal alternatives.

The International Desalination Association’s (IDA) State of the Nation report in 2011 showed that out of the global 66.48 million m³/day installed capacity, RO accounts for 59.85%. MED and MSF meanwhile account for 8.20% and 25.99%, respectively.

IDE Technologies provides both processes. For SWRO, it has references at Hadera (127 million m^³/year) and Ashkelon (118 million m^³/year) in Israel, as well as Larnaca in Cyprus (21.5 million m^³/year) and Sorek to be completed by the end of 2013.

For thermal, in 2010 the SDIC Tiajin Electric Generation Plant commissioned IDE Technologies for the Engineering, Procurement and Construction services for China’s largest thermal desalination plant. The 200,000 m^³/day MED is designed with an ultimate capacity of 400,000 m^³/day.

IDE Technologies’ CEO said it is in difficult to treat waters where thermal desalination’s future lies.

“There will still be a place for thermal because firstly there’s progress in thermal all the time and secondly because some waters will always be better to treat or at least partially treat, with a thermal process because of the cost of preparing them for the RO,” he said.

“As this can be very complex and intense in order for the water to eventually meet the membranes – it’s sometimes easier to treat with thermal. And also, where there’s waste heat and there’s really nothing to do with it, then thermal can get its heat for free.”

The IDA’s report said that there would be an “increase in hybrid plants combining thermal and membrane processes”.

Felber added: “I would say there’s a place for hybrid solutions that combine the advantage of both technologies. I wouldn’t say that robustness is the only advantage you can get from thermal, as RO is getting more and more robust and it’s just a standard of operation that would allow you to work well or not.”

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- The full interview with IDE Technologies CEO Avshalom Felber will appear in the June-July issue of WWi magazine. To sign up for your free copy, please click here.