China to industrialise desalination of sea-ice

During an ice age as water gets trapped in expanding ice, the entire water cycle stabilises at much lower rates of flux than during an inter-glacial period. Evaporation (due to absorption of solar energy) is the primary force which drives the water cycle. During an ice age, rates of evaporation will decrease sharply, precipitation will reduce and the flow of fresh water through rivers and streams back into the seas will reduce as a consequence. Sea levels would drop by up to 150 m from current levels and while currently submerged land will be exposed, desertification of many regions will also take place.

One of the technologies that will be necessary at such a time will be for the extraction of fresh water from sea ice.

Bohai Bay China

Bohai Bay China

The Bohai Rim is one of the water-scarce regions in China. But every winter, more than 1 billion m3 of sea ice formed in the sea, about 40% of which distributes within 10 km offshore and is expected to be exploited and utilized as source of freshwater.

They may not be expecting a return to full glacial conditions anytime soon, but perhaps the Chinese are already preparing for another Little Ice Age and the fresh water availability reduction that will undoubtedly cause.

Xinhua reports:

China will soon begin production of large amounts of fresh water through the desalination of sea ice, according university research team and a Chinese company on Tuesday. A research team from Beijing Normal University signed a sea ice desalination technology transfer agreement with Beijing Huahaideyuan Technology Co. Ltd on Tuesday.

The company is expected to be able to produce at least 1 billion cubic meters of fresh water annually by 2023, said Yu Jian, executive president of the company. The salinity of sea ice is between 0.4 percent to 0.8 percent, much lower than that of sea water, which stands at about 2.8 percent to 3.1 percent, said Professor Gu Wei, head of the research team.

The research team has mastered the basic principles and technology of sea ice desalination and developed the equipment to be used in the process, including an ice-breaking platform and an ice-gatherer, he said. The salinity of sea ice water after desalination is 0.1 percent, which meets the national standard. The water can be used in agriculture, by industry and for drinking, he said.

The cost of desalination is expected to fall to 4 yuan per tonne, he said.

China’s sea ice desalination program started in 1996 when Shi Peijun, a professor from Beijing Normal University, realized that low saline ice could ease the water shortage around the Pan-Bohai Bay area in north China, after desalination. The program has received a total of 29.72 million yuan (4.88 million U.S. dollars) from various government departments in the past 18 years.

In winter in high-latitude oceans, there is a great amount of sea ice, which is being recognized as a new resource of fresh water by scientists.

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