(572f) The Prospect of Using Lng Regasification as a Heat Sink for Seawater Desalination

Natural gas is a major fuel source for electricity generation, and is used in homes for heating and cooking. It is considered to be a clean and efficient gas, and is generally accepted as non-toxic.

Over short distances, the transportation of natural gas, such as from Indonesia and Malaysia to Singapore, is achieved through pipeline. However, across long distances and oceans, this is not practical. Natural gas is instead liquefied and transported on LNG carriers. As of August 2005, there are 28 LNG liquefaction facilities and 50 LNG regasification terminals throughout the world. The main LNG importers are Japan, Korea, Europe, and United States while the main LNG exporters are Algeria, Australia, Malaysia, Nigeria and Indonesia.

Conventional LNG regasification requires an external heat source. This heat is supplied by various types of vapourisers, in which seawater is the most common process medium. The regasification acts as a heat sink to regasify the natural gas back to gaseous form, while the seawater is cooled and discharged back to the ocean.

An exploratory project has been set up to explore the prospect of desalinating seawater (i.e., with a typical salinity of 3.5%). Seawater is taken below the freezing point to produce an ice and salt solution mixture.

This paper discusses the economic value of the proposed process. In addition, preliminary results of the quality of water produced based on small-scale batch studies will also be discussed.