Showa Denko Aluminum Trading K.K. (SDAT), a consolidated subsidiary of Showa Denko K.K. (SDK), has launched a new type of evaporator for liquefied natural gas (LNG) through heat exchange with the atmosphere, enabling long hours of continuous operation.
The device, consisting of aluminum-fin tubes, is a relatively large outdoor heat exchanger that fully utilizes the high thermal conductivity of aluminum.
After evaporation, the natural gas is used in power generation and as city gas.
Since LNG generates less carbon dioxide at the time of burning compared with oil and coal, consumption of LNG will increase as a measure to prevent global warming.
Thus, demand is expected to expand for LNG evaporators that use the heat of the atmosphere.
Conventional LNG evaporators involve such problems as short continuous operation time; generation of a fog as a result of the cooling of atmospheric vapor under humid conditions; and ice-coating on fin-tubes resulting from the adhesion of frost, especially in cold districts.
SDAT has introduced a drift prevention system inside the fin tubes, thereby achieving a uniform rate of LNG vaporization and limiting the difference in liquid levels inside the tubes.
As a result, SDAT has gained greater freedom in evaporator design and succeeded in doubling the continuous operation time, up to eight hours.
In case the conventional four-hour continuous operation is preferred, SDAT can provide a smaller version, enabling the device to be installed in a narrow space.
SDAT has also developed an air-introduction system* and a sprinkler system to substantially increase the efficiency of melting frost and ice that adhere to the evaporator.
As these systems restrict the generation of a fog and shorten the time of ice melting in cold districts, the evaporator running costs will be reduced substantially.
(*The air-introduction system can be added after installation).
[mappress]
Source: Showa Denko K.K., June 17, 2010;