Evaporation Desalination System from NEWater

Seawater desalination technology can effectively solve the crisis of freshwater resources. The NEWater evaporative seawater desalination system is characterized by vacuum technology to reduce the boiling point of seawater and concentrated seawater, and the maximum evaporation temperature of seawater under a certain vacuum condition is not greater than 70℃, which effectively slows down the seawater Fouling of heat exchange equipment and inorganic salt corrosion during the evaporation process.

The reduction in operating temperature of our evaporative seawater desalination system during the evaporation process can effectively reduce the requirements for equipment materials. Only the first-effect evaporator needs to provide an external heating source, and the remaining effects are circulated through the latent heat of the secondary steam, which greatly reduces your process investment and energy consumption.

NEWater has a group of experienced, rigorous, innovative, and thoughtful engineering design and production technicians. Our evaporative desalination system has low pollution, a small footprint, good effluent quality, energy-saving, and convenient installation, which make us stand out in the market. At the same time, the system can continuously provide freshwater resources for human production and life.

Contact us now and have all your questions answered by our customer representative!

The Ultimate FAQ Guide to Evaporative Desalination

Long before the invention of membrane-based desalination, ancient humans in water-deprived regions mainly relied on evaporative desalination for freshwater. Improvements were made and gradually evaporative desalination became more productive and power-efficient. With evaporative desalination plants, communities and industries in water-scarce regions can now access fresh potable water easily. This article explores desalination by evaporation and its efforts in tackling freshwater shortages.

➣What is Desalination?

Desalination is the process used to lessen the number of dissolved solids present in salty water. Desalination simply generates fresh potable water from seawater or brackish water thereby reinforcing freshwater sources.  Contemporary desalination methods are highly advanced and effective exhibiting salt rejection rates of up to 99.4%.

Principally, desalination is achieved through evaporative desalination or reverse osmosis processes. It is a prominent freshwater source for countries in arid and semi-arid regions such as the Middle East and North Africa.  The continuing depletion of freshwater reservoirs is, however proliferating desalination in other parts of the globe.

➣What is Evaporative Desalination?

Desalination by evaporation is a freshwater generation mechanism that imitates the indigenous process of rain formation. By heating salty water at low pressure, irreversible evaporation is prompted leaving behind dissolved solids because they are incapable of turning into vapor. Consequently, the vapor is then condensed and ultimately collected in a separate jar as freshwater.

Evaporative desalination is primarily achieved using thermal distillation processes namely, multi-effect distillation, multi-flash stage distillation, and vapor compression.  By integrating renewable energy, evaporative desalination has emerged as a cost-efficient, reliable water treatment solution for coastal and arid countries.

➣What are the Benefits of Using Desalination by Evaporation?

Statistics depict that over a third of countries across the world are incapable of meeting the domestic, industrial, and commercial demands for freshwater. To counter such deficits, the efficiency and resourcefulness of desalination are needed. Desalination by evaporation is a dependable alternative source of fresh potable water exploiting inexhaustible water sources. Below we look at the benefits evaporative desalination brings to the ecosystem and its inhabitants:

• By using renewable solar energy, evaporative desalination mitigates environmental degradation caused by greenhouse emissions from fossil fuels.
• Desalination by evaporation has high salt rejection rates.
• The equipment needed is quite affordable and easy to install.
• Evaporative desalination produces high-quality water for human consumption and industrial processes.

➣Where is Evaporative Desalination Applied?

Evaporative desalination is a vital remedy to the freshwater shortage. This implies that it is applicable in virtually all domestic, commercial, and industrial activities necessitating fresh water. Communities in coastal and dry regions exploit desalination by evaporation to generate clean drinking water from seawater. Industries and commercial enterprises also rely on evaporative desalination to augment their supply of potable water. Underneath are common applications of evaporative desalination system:

• Boats and other water vessels.
• Supplying fresh water for domestic use.
• Supplying hotels and restaurants with potable water.
• Generating freshwater for businesses such as car washes.

➣What is the Difference between Reverse Osmosis and Evaporative Desalination?

Both evaporative desalination and reverse osmosis processes are effective technologies used to produce freshwater from seawater or brackish water. Despite exhibiting similar results, the two processes exhibit numerous distinctions. To begin with, the evaporative desalination process is principled on thermal distillation while reverse osmosis is a membrane-based process.

Secondly, reverse osmosis consumes more power when desalinating highly alkaline feed water while the energy consumption in evaporative desalination is not influenced by salinity concentration. This makes desalination by evaporation more efficient when desalinating feed water with high salinity rates.

➣How Does Desalination by Evaporation Function?

Evaporative desalination is typically regarded as a simple yet effective method of generating fresh water from saline water. Essentially, it is based on the same principles as natural rain creation. The salty water (seawater or brackish water) is heated to provoke evaporation and consequential condensation of the vapor.

The dissolved salts and other contaminants found in the salty water are separated from the freshwater given they cannot vaporize while the freshwater is collected in a distinct container. Desalination by evaporation is extremely reliant on thermal power but recent advancements allow recycling of the thermal heat thereby lowering energy consumption.

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➣Can Evaporative Desalination Produce Fresh Drinking Water?

Long before the invention of reverse osmosis in the 1960s, ancient communities in arid and semi-arid regions relied on solar evaporation desalination to quench their thirst. In addition to eradicating dissolved salts, evaporative desalination ejects microorganisms such as bacteria and viruses from the sea and brackish water. As such, high-quality drinking water is generated.

According to the World Health Organization, water viable for drinking should at most contain 900 milligrams of dissolved salts per liter. 500 mg/L is the ideal rate proposed by health experts and advanced evaporative desalination plant often produces potable water within those parameters.

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➣What are the Various Evaporative Desalination Methods?

Efforts to improve evaporative desalination and diversify its application have given birth to various desalination techniques. Underneath are some of the most prominent evaporative desalination technologies.

Vapor compression.

Vapor compression is evaporation–based technology that generates the required energy from compressing vapor. For mechanical vapor compression, a mechanical compressor is necessitated while thermal vapor compression utilizes steam jets to generate energy from vapor condensation. This energy is in turn utilized to evaporate the feed water while the condensed vapor is collected as fresh potable water.

Multi-effect distillation.

MED distillation is a process carried out in several stages often referred to as effects. To generate freshwater, multi-effect distillation evaporates feed water and condenses the resulting vapor at progressively lower ambient pressure per evaporator. The MED distillation process is typically carried out in 4 to 21 stages (effects).

Multi-stage flash distillation.

Multi-stage flash distillation is a prominent desalination process accounting for a huge chunk of freshwater generated through desalination. Through heating, MSF distillation ensures the temperature of the feedwater is below the saturation boiling point. The flashing effect is then utilized whereby the chambers with a gradual low pressure are injected with hot water forcing the water to flash into steam.

Other evaporative desalination processes include:

• Solar water evaporation.
• Cogeneration.

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➣How Effective is Desalination by Evaporation?

Evaporative desalination generates fresh potable water by alienating dissolved solids from seawater. Thermal desalination processes such as the multi-effect and multi-stage flash distillations have shown they can reject over 95- 99% of dissolved salts found in saline water. Their ability to desalinate extremely saline water (with over 35,000ppm) without necessarily consuming more energy makes them a cost-efficient alternative to membrane-based processes.

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➣What are the Advantages of Vapor compression Evaporations?

Vapor compression machines are often conventional small-sized equipment suitable for small-scale applications. Typically, they have capacities of up to 3000 cubic meters per day and are extremely efficient in their power consumption.

The operational temperature of vapor compression evaporators is mainly lower than 70°C. This mitigates scaling and corrosion of the machinery. Consequently, they are perfect desalination solutions for residential, resorts, and small industrial applications.

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➣Can Evaporative Desalination Solely Rely on Solar Power?

Ancient evaporative desalination was chiefly powered by solar energy generated from the sun. Solar-powered desalination evaporators are mainly categorized into direct and indirect solar desalinators. Direct solar stills generate fresh portable water proportional to the solar surface area. Approximately, this is 3 or 4 liters for every square meter.

Indirect solar evaporators, on the other hand, rely on solar collectors made of photovoltaic collectors to absorb and transmit thermal energy to the evaporators. They include multi-effect and multi-stage flash desalinators.

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➣What Devices are Used in Evaporative Desalination?

Multiple desalination machines utilizing evaporative desalination are in force in various parts of the world. Desalination evaporators are available in distinct capacities and dimensions, therefore, accommodating small-scale and large-scale applications. Underneath are some evaporative desalination machines available in the modern market.

Thermal Vapor Compressors.

Thermal vapor compressors are specialized machines that rely on steam jets to generate the energy needed to desalinate saltwater. The evaporators are often made of titanium plates to mitigate corrosion and prolong their lifespan. They are mainly applicable in industrial applications and due to their small footprint, can be used in homes.

Multi-effect Evaporators.

There are custom-built multi-effect evaporators that produce freshwater from feed water through evaporation and condensation. They are manufactured in varying capacities and are ideally suited for industrial and commercial applications. Components of a single-effect evaporator include:

• Evaporation chamber fitted with an inbuilt heating section.
• A vapor or liquid separator.
• A condenser made of the barometric leg.
• A vapor-ejector vacuum system.

Multi-stage flash evaporators.

Multi-stage flash desalination systems are the most prevalent evaporation desalination systems in the world. Evaporation, condensation, and water collection are mainly carried out in three fragments.

• Heat input.
• Intermediate heat recovery.
• Heat rejection.

They are ideal for industrial applications and have varying capacity ranges.

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➣Can Evaporative Desalination Work on Seawater?

Coastal regions are often forced to reinforce their scarce freshwater supply with desalinated seawater. Despite being highly saline, evaporative desalination manages to eliminate over 95% and in some instances 99% of dissolved salts and other constituents found in seawater.

At first, the seawater is screened to eradicate debris and other large constituents present. Subsequently, the seawater is heated, vaporized, condensed, and finally collected as fresh potable water. Unlike reverse osmosis, evaporative desalination treats highly concentrated seawater at normal power consumption rates.

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➣What Contaminants are Eradicated by Evaporative Desalination?

Desalination generally creates fresh potable water by eliminating dissolved salts and unwanted pollutants found in feed water. Evaporative desalination is a simple and productive technology that humans have used for ages to generate freshwater. Under the right conditions, it has been evidenced that it can reject up to 99% of dissolved salt. Underneath are unwanted impurities ejected from seawater by evaporative desalination.

• Dissolved ions.
• Bacteria and viruses.
• Protozoa.
• Colloids.
• Chemicals such as arsenic and chloride.

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➣What are the Challenges Facing Evaporative Desalination?

Evaporative desalination plays a huge role in providing fresh water to regions with limited freshwater supply. To attain this, the process comes at a price and in some instances deter prospective consumers from investing in desalination evaporators. The following are common limitations of desalination by evaporation.

• The systems can be expensive to purchase and maintain.
• Power consumption rates are relatively high.
• The wastewater is highly concentrated and a threat to the environment.

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➣What are the Advantages of Multi-effect Desalination?

Multi-effect desalination generates over 3.5% of global desalinated water. This process is characterized by satisfactory power efficiency and high salt rejection rates, which ultimately makes its operation cost-efficient. Below, we take a look at the advantages of multi-effect desalination systems.

• Compared to multi-stage flash desalination systems, MED desalination’s power consumption is quite efficient.
• Pre-treatment in MED systems is cheaper resulting in an overall inexpensive cost of operation.
• The productivity of MED systems is higher compared to multi-stage flash distillation.

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➣What are the Advantages of Multi-stage Flash Desalination?

Multi-stage flash distillation carries out the desalination process in multiple stages, which improves the quality of potable water generated. Ordinarily, the stages in multi-stage flash distillation range from 12 to 26 stages. Underneath are the advantages of the most commonly used thermal desalination method.

• MSF systems generate portable water with less than 10 ppm.
• They are easy to operate.
• High operating temperatures (at least 115°C) improve the efficiency of MSF systems.

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➣Can Evaporative Desalination be Used in Industrial Applications?

Evaporative desalination plants such as multi-effect and multi-stage flash systems are manufactured with capacities and efficiencies that accommodate industrial applications. Multi-stage flash desalination systems meant for large-scale applications have the capacity to generate up to 528, 000m3 of potable water in a day.

Multi-effect desalination, on the other hand, can generate up to 320, 000 m³ of fresh water in a day. Recent innovations have lowered the operational costs of evaporative desalination thereby encouraging its use in industrial applications.

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➣How Much Potable Water Can Evaporative Desalination Generate?

The amount of potable water produced by an evaporative desalination machine in an hour or a day differs depending on the capacity and desalination process used. Standard vapor compression systems have the capacity to generate around 1000 cubic meters of potable water in a day. This capacity sufficiently accommodates small-scale domestic, industrial, and commercial applications.

Multi-effect desalination plants have standard production rates ranging from 91000 m³ to 320,000 m³ per day. On the contrary, multi-stage flash desalination can produce between 23,000 m³ and 528,000 m3. By having the capacity of your system customized, you can get your desired daily production rates.

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➣Do You Manufacture Evaporative Desalination Equipment?

NEWater’s production niche extensively covers most thermal and membrane-based water treatment solutions. Our state-of-the-art production machinery and highly proficient team of engineers permit us to manufacture a comprehensive range of evaporative desalination equipment.

Our evaporative desalination plants include vapor compression devices, multi-effect distillation systems, and multi-stage flash evaporators. We customize the systems based on your feed water’s composition and your capacity demands. For further details, reach out to our engineers.

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➣What Powers Evaporative Desalination?

Desalination by evaporation is a process that necessitates solar energy or electrical power to initiate and sustain the evaporation and condensation processes. As such, evaporative desalination tends to be more power-intensive, especially when compared to other modern desalination processes like reverse osmosis.  A standard evaporative desalination system consumes approximately 15-16 KWh/m³ of power to produce product water. Comparatively, the reverse osmosis process only consumes 5-6 KWh/m³  

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➣How Much Does it Cost to Generate Potable Water Using an Evaporative Desalination System?

To determine the total production cost of evaporative desalination, you need to calculate the cumulative equipment fee, installation fees, power consumption, and labor fees. Evaporative desalination systems reliant on thermal processes powered by fossil fuels tend to drive up the cost of desalinating a unit of water.

Desalinating high amounts of water is technically cheaper thus large plants have lower production costs per unit. As an illustration, a mechanical vapor compressor with a production capacity of 1000 m³/day costs around 2 to 2.6 dollars per cubic meter. On the flip side, desalinating a similar amount of water using a large MED system costs approximately 0.5 to 1.01 dollars per cubic meter.

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➣What are the Emerging Trends in Evaporative Desalination?

Evaporative desalination processes and equipment have been subject to modification and consequential upgrades over the years. Manufacturers of evaporative desalination systems are continually seeking to better the technology in efforts designed to make the system more cost-efficient and elevate its productivity.

Population increase has increased the demand for freshwater while freshwater sources suffer from adverse climatic changes. This has led to an increase in the use of evaporative desalination processes and machines across the world. Additionally, technology that permits the reuse of thermal heat in evaporative desalination has fundamentally lowered power consumption.

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➣Do You Ship Systems Overseas?

NEWater is a top-notch manufacturer of comprehensive water treatment systems with a global reach. All our products including evaporative desalination equipment are delivered to our customer’s doorsteps in over 200 global destinations. NEWater uses internationally renowned shipment service providers to ensure you get your systems delivered safely and on time.

Your order of small modular evaporative desalination systems shipped through air transport will be delivered within 3 to 7 days. Conventional large equipment will however take approximately 2 to 3 months. Shop your desalination system from NEWater and avoid the shipping and customs clearance hassle.

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➣Is Evaporative Desalination Friendly to the Environment?

Evaporative desalination by providing an alternative source of freshwater alleviates the pressure put on freshwater sources thereby aiding environmental conservation attempts. In addition, evaporative desalination powered by renewable sources of energy such as wind and solar power mitigates carbon emission from fossil fuels.

However, inappropriate disposal of untreated brine from evaporative desalination could be of great disservice to the environment. Thermal desalination utilizing fossil fuels for power could also have a greenhouse effect on the environment.

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➣Can Evaporative Desalination be Used in Homes?

Small-sized thermal desalination systems can be installed in homes to generate freshwater from seawater, brackish water, or salty well water. Vapor compression plants are compact in size and particularly suited for small-scale water desalination.

Desalination by evaporation is however a power-intensive process, especially when desalinating low quantities of water. A cost-effective mechanical vapor compression system powered by solar energy would however be ideal for small applications such as the domestic supply of potable water.

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➣Can Evaporative Desalination Treat Brackish Water?

Evaporative desalination is an effective desalination solution for salty water with TDS levels ranging from 1000 ppm to over 35,000 ppm. The concentration of total dissolved solids in brackish water ranges from 1,000 ppm to 10,000 ppm. Evaporation and condensation of brackish water through multi-effect, multi-stage flash distillation, or vapor compression results in high-quality potable water. Brackish water desalination through evaporative desalination eliminates over 97% of dissolved salts and other imminent pollutants.

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➣Do You Manufacture Alternative Desalination Systems?

NEWater is your one-stop shop for all your water treatment products. For over 20 years, we have perfected our production processes and machinery to ensure our products are of unrivaled quality. We specialize in the development of industrial, domestic, and commercial water treatment solutions. You can procure your desired desalination system from our standard options or request a customized solution. Below are some desalination systems from NEWater that can augment your domestic, industrial, or commercial supply of freshwater.

• Reverse osmosis systems.
• Seawater desalination systems.
• Membrane cleaning systems.
• Purified water generation systems.

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➣Do You Have Portable Evaporative Desalination Devices?

By mounting evaporative desalination devices on metal rails and standard containers, we manage to create portable systems. A portable evaporative desalination plant widens the application scope of the plant given it can easily be transported to different sites for desalination purposes.

For mobility, we assemble and mount all components of our VC, MED, and MSF desalination plants on skid mounts. This makes the mobile evaporative desalinators easy to set up and operate. To order or inquire about portable evaporative desalination units, reach out to our technicians via info@newater.com.

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➣What is the Life Expectancy of Evaporative Desalination Devices?

The condensers in Multi-effect desalination systems are made of titanium, which equips the systems with anti-erosion, therefore, elongating their lifespan. Similarly, the nozzle sprays found in mechanical vapor compression plants are made of acetyl, which is resistant to corrosion and clogging. Generally, evaporative desalination systems are long-life units capable of withstanding high temperatures, thwarting corrosion, and relentlessly generating high-quality, freshwater.

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