Man-made Natural Gas Hydrate 06-20-2005 17:50

What is this combustible ice-like substance? It鈥檚 hydrate of natural gas, also called combustible ice.

The total energy conserved in combustible ice is 2-3 times as much as that contained in coal, petroleum, and natural gas found in the world. In the floor of the South China Sea and the permafrost of Qinghai-Tibet Plateau are huge combustible ice reserves.

Combustible ice is the largest energy resource in the 21st century. But it turns into water and natural gas at normal temperatures and pressure, so it can鈥檛 be easily exploited or transported. While most countries are engaged in research on natural gas hydrates, China has expanded its national development program to include artificial synthesis, surveying, exploitation, and transport of combustible ice.

Under suitable temperatures and pressure, the methane and ethane molecules in natural gas easily enter this cave-like ice to form stable natural gas hydrate structures.

In order to simulate the formation and decomposition processes of natural gas hydrate in nature, Chinese scientists at Xi鈥檃n Jiaotong University independently designed this equipment for the artificial synthesis of natural gas hydrates. They put some crushed ice into a hermetic container that can be kept at low temperatures, and then poured natural gas with a certain pressure into the container. At a low temperature and high pressure, after several hours of reactions, man-made natural gas hydrate is formed.

Through man-made natural gas hydrates, scientists can learn how natural gas hydrates are formed, systemically study their physical and chemical properties, and simulate their formation and decomposition conditions in the sea floor and permafrost. This can provide important technical data for the survey and exploitation of natural gas hydrates in the sea floor and permafrost.

Combustible ice can store gases. A liter of combustible ice can store 164 liters of natural gas. The mixture can remain stable at normal pressure and a refrigeration temperature. Therefore, turning natural gas into a solid hydrate is a cheap, safe and reliable way to store and transport natural gas.

The West-East Natural Gas Transmission Pipeline Project is a major project being implemented. It uses pipelines to transfer natural gas from Xinjiang to Shanghai. The pipelines have to pass through some cold regions, where natural gas hydrates can easily form to block the pipelines, gas wells, or equipment.

Through the artificial synthesis research on natural gas hydrates, we can learn how they form in the pipelines to figure out ways to prevent them from blocking the pipelines.

The Qinghai-Tibet Railway is another important project in China. The railway passes through permafrost that contains large amounts of natural gas hydrates. Therefore, Chinese scientists have artificially synthesized natural gas hydrates that contain sand and stones and conducted pressure experiments at various temperatures to provide necessary data for the project.

The artificial synthesis technology for natural gas hydrates can be used to separate gaseous mixtures, dry gases, and desalinate seawater. It can also be used in deep sea storage of carbon dioxide, to control bioactive enzymes, synthesize nano semiconductor crystals, and many other areas.

With the strengthening of the artificial synthesis research on natural gas hydrates, the ideal way to exploit and transport combustible ice is certain to be discovered. By then, each of us will be able to use environment-friendly and inexpensive natural gas.

Editor:Wang Ping

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