Desalination with renewable energies Provide by : iman mafakher

DESALINATION A process for removing dissolved minerals (including, but not limited to, salt) from seawater, brackish water, or treated wastewater A number of technologies have have been developed for desalination: reverse osmosis, electrodialysis, vacuum freezing, distillation, capacitive deionization. increasing due to population growth and economic development. The International Desalination Association (IDA) reports that there are about 15,000 desalination plants worldwide, with a global capacity of 71.7 million m3/d.

KEY DESALINATION FACTS Energy costs are a principal barrier to greater use of desalination technologies (disposal of residual brine is another) More than 120 countries are now using some desalted seawater, but mostly in the Persian Gulf where energy costs are low (oil, natural gas) Cost of seawater desalination using reverse osmosis has fallen: $23 per 1,000 gallons in 1978 ($5.26/m3) $2 per 1,000 gallons ($0.55/m3) today (Tampa: 35 million m3/day)

Joint technology development driving energy and cost out 2010 1996 1.25 0.25 0.75 Cost of Water $/m3 Cost of ‘Traditional’ Water Supply Cost Water Reuse Cost of Desalination 0.50 1.00

Renewable Energy Sources Solar Thermal Desalination Photovoltaic Desalination Wind Power Desalination Geothermal Desalination

…. ! At present, only 0.36% of the world’s waters in rivers, lakes and swamps is sufficiently accessible to be considered a fresh water resource The most commonly used desalination method is multi-flash distillation The most commonly used solar powered desalination method is passive evaporation

Desalination potential

reverse osmosis فرایندی است که در آن از فشار برای معکوس نمودن جریان اسمزی آب از درون یک غشای نیمه‌تراوا استفاده می‌شود. به علت کیفیت بسیار عالی آب خروجی از سیستم اسمز معکوس امروزه بیشتر صنایع از این روش، بجای بکارگیری سیتمهای تعویض یونی استفاده می‌کنند. زیرا مبادله کننده‌های یونی به علت مصرف زیاد مواد شیمیایی و رزین، دارای هزینه راهبری و نگهداری زیادی می‌باشند. Feed-water is brought to the surface of a membrane, which selectively passes water and excludes salts.

electrodialysis Electrodialysis (ED) is used to transport salt ions from one solution through ion-exchange membranes to another solution under the influence of an applied electric potential difference. in that dissolved species are moved away from the feed stream rather than the reverse. Because the quantity of dissolved species in the feed stream is far less than that of the fluid, electrodialysis offers the practical advantage of much higher feed recovery in many applications

vacuum freezing

MULTY-FLASH DISTILLATION between 90 and 110 C° , with a decreasing pressure through the stages. MULTY-FLASH DISTILLATION

capacitive deionization brackish water, which is water with a low or moderate salt concentration (below 10 g/L) CDI is considered to be an energy-efficient technology for brackish water desalination.

KEY DESALINATION TECHNOLOGIES Reverse Osmosis: pressure is applied to intake water, forcing water molecules through semipermeable membrane. Salt molecules do not pass through membrane. Product water that passes through is potable. On average, energy (electrical) accounts for 41% of total cost. 5,800-12,000 kWh/AF (4.7-5.7 kWh/m3)* Distillation: intake water heated to produce steam. Steam is condensed to produce product water with low salt concentration. energy requirements for distillation technologies (electrical and thermal) are higher than for reverse osmosis technologies. 28,500-33,000 kWh/AF (23-27 kWh/m3)* ------------------------------------------------------------------ * does not include energy required for pre-treatment, brine disposal and water transport solar energy – in particular heat from concentrated solar power (CSP) for thermal desalination and electricity from solar photovoltaic and CSP for membrane desalination

LIFE-CYCLE COST ANALYSIS Solar Powered vs LIFE-CYCLE COST ANALYSIS Solar Powered vs. Conventional Water Pumping Systems

El Jeromín, Chihuahua results

Life-Cycle Cost Analysis Case Study-El Jeromín, Chihuahua

CONCLUSIONS Water issues will be a major global concern in the 21st century, and a potential source of conflict Addressing water issues requires joint consideration of a broad range of issues – health, agricultural, economic, political and energy Water and energy issues are closely linked Renewable energy is likely to play a major role in addressing water issues, especially in developing countries Where applicable, a systems approach will yield optimum results Current information on desalination shows that only 1% of total desalinated water is based on energy from renewable sources.

CONCLUSIONS While desalination is still costly, declining renewable energy technology deployment c Renewable technologies that are suited to desalination include solar thermal, solar photovoltaics (PV), wind, and geothermal energy.osts are expected to bring this cost down in the coming years. Reverse Osmosis (RO), 60% of the global capacity Multi Stage Flash (MSF), with a 26.8% The cost of desalination has been decreasing over the last years down to USD 0.5/m3, while market prices for desalinated water are typically between USD 1/m3 and USD 2/m3. Seawater desalination via MSF consumes typically 80.6 kWh of heat energy (290 MJ thermal energy per kg) plus 2.5 to 3.5 kWh of electricity per m3 of water, while large scale RO requires only about 3.5 to 5.0 kWh of electricity per m3. First : United Arab Emirates, Kuwait, Algeria and Libya ,then China and India are high potential markets ,next

Resources Water Desalination Using Renewable Energy ,IEA-ETSAP and IRENA© Technology Brief I12 – March 2012 WATER, ENERGY & SUSTAINABLE DEVELOPMENT , Water Policy in the Americas Roundtable Organization of American States , Dr. Allan R. Hoffman ,U.S. Department of Energy ,June 15, 2000 Solar Powered Desalination , Energy Systems ,Devyn Haycox & Jeff Taisch– Fall 2004

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