Summary:

The UN says 5 billion people will live in water-stressed areas by 2050. We need better, cheaper, and easier-to-get water solutions every year as this stress grows. Seawater desalination, while effective, needs to get more efficient and affordable for everyone. This article explores heat composites and a new polymer composite as ways to make desalination work better.

Description:

Seawater desalination simply separates salt and chemicals from ocean water. It’s the filtration process that gives people drinking water, even when fresh water is scarce. Desalination plants worldwide mostly use one of two main methods: Reverse Osmosis or Distillation. Reverse osmosis is more advanced and efficient, but distillation is an older method that mainly just needs energy.

Reverse Osmosis pushes salty water through a special membrane to get pure water. This takes a lot of effort, like treating the water and keeping membranes clean. Distillation, on the other hand, just boils water. The pure water vapor rises into a condensing chamber, giving you streams of pure water. These are the two big ways we desalinate seawater globally, and nothing else has really come close to filtering large amounts of water effectively.

Heat Composites for Seawater Desalination

Back in 2012, people suggested another process using heat composites. Some countries, like Spain and Portugal, still use this method today. These places deal with severe water shortages every year, so they rely on seawater desalination. Their method involves putting heat composite pipes in desalination chambers. Here’s how it works.

The Process

Seawater sprays onto the composite pipes. These pipes get hot from hot gas or water flowing through them. The increased temperature turns the water into vapor, which then goes to condensing chambers. What’s left behind is a thick sludge of salts, chemicals, and other unwanted stuff. For this method to really shine, the pipes need to be strong and meet these requirements:

• They must conduct heat well, handling the high temperatures needed to evaporate water.
• They need to resist corrosion, because that salty sludge will build up every time.
• They should be durable and work well for a long time, cutting down on maintenance and costs.
• Seawater must easily coat them.

 

The Alternative

Because these pipes need such specific properties, companies used titanium or steel alloys before. But these materials aren’t easy to find, so prices shot up, and availability dropped year after year. To tackle this, scientists at Fraunhofer IFAM, Bremen, Germany, came up with a polymer composite alternative.

Their big win? The polymer conducted heat, even though it was plastic, and they could build it in continuous lengths. They made it heat-conductive by adding metal particles. About 50% copper microfibers went into the polymer to help it conduct heat. After building the composite, improving its thermal conductivity was another key challenge. To do this, they ran a series of tests, checking how much sludge formed. They kept the hot gas at 70 degrees Celsius.

They then tweaked the composite’s properties to reduce salty sludge, based on how much corrosion they saw. The results showed less leftover material on the composite, less corrosion, and not much pressure difference inside and outside the pipe.

Possible Applications

This composite isn’t just for seawater desalination. It could also help in pharmaceutical and food industries. The composites look promising in seawater desalination, but we haven’t seen them used widely yet, outside of a few countries. Over time, reverse osmosis has proven to be a much more effective water filtration method. That’s why most companies and desalination plants worldwide use it as their primary process.

Water is something no one can afford to lose. With worse droughts each year, it’s getting harder to give people drinking water. The UN reports that water shortages could affect billions by 2050. So, we really need to keep developing technologies that use seawater’s potential in any way we can.

Author’s Bio:

Ampac USA builds top-notch reverse osmosis water treatment systems. For over 30 years, we’ve helped customers worldwide with their water treatment issues. With a long track record, Ampac aims to create solutions that make reverse osmosis systems better, improving quality and cutting costs.

References:

1. https://www.materialstoday.com/surface-science/news/heat-conducting-composites-for-seawater/
2. https://www.sciencedaily.com/releases/2012/10/121004093245.htm
3. https://www.designnews.com/materials-assembly/composite-conducts-heat-remove-salt-seawater/7906506032374
4. https://www.theguardian.com/environment/2018/mar/19/water-shortages-could-affect-5bn-people-by-2050-un-report-warns

Related reading: What is Seawater Desalination, and How Does a Seawater Desalination System Work?, Seawater desalination-the most viable solution to drought!, AMPAC USA Portable Seawater Desalination Solution for Boats.