On the worldwide list of countries transporting and producing liquefied natural gas or, in short, LNG, Malaysia is in third place. The country’s largest manufacturer Petronas recently invited tenders for a De-bottlenecking Project for one of its three LNG plants. With this system, gas escaping while natural gas is converted into liquefied gas in the existing plants, is to be recirculated, resulting in an increase of the overall production output of liquefied gas. Voith Turbo contributes to the project with a geared variable-speed coupling.
The demand for natural gas is rising faster than the consumption of oil. As a result, the access to and better availability of natural gas are increasingly coming into focus. The advantage of liquefied gas lies in its independence of pipelines, which are always technically and politically complex. This means that natural gas is no longer a ‘regional’ energy. Additionally, natural gas fields can be utilised better or indeed be used at all. After all, two thirds of the existing reserves are considered as economically unsuitable for connection to pipelines. By 2010, the worldwide consumption of liquefied gas is to rise to 250million tons, a growth rate of some 40percent over the past 10 years. The main consumers are North America and Asia, using up more than half of the available quantities. In future, Voith geared variable-speed couplings will be used for a more efficient production of liquefied gas through ‘de-bottlenecking’.
During the production process of liquefied gas, a certain amount of natural gas evaporates. With the help of end-flash gas compressors, gas that would normally escape unused, is collected and recirculated into the manufacturing process. Through this de-bottlenecking, the overall capacity of the plant is considerably increased.
The end-flash gas compressors are driven and speed-regulated by Voith Turbo geared variable-speed couplings. Unlike large cooling compressors, they are not powered by gas or steam turbines, but by electric motors. The decision in favour of the Voith Turbo drive concept was made against the background of the MLNG plant Tiga already operating with two identical units that have been in trouble-free service for many years.
Voith Turbo will deliver a total of three such geared variable-speed couplings for the MLNG plant Dua in Bintulu in the East of Malaysia. For the liquefied gas production, the natural gas is directed into ‘trains’. In these trains, the gas is cooled down to minus 162°C and consequently liquefied. Via tankers or special trains it is then forwarded to its further destinations. The LNG plant in Bintulu has three such trains.
The annual output of the Dua MLNG plant currently amounts to 7.8million tons.

Voith Turbo GmbH & Co KG is based in Crailsheim, Germany. www.voithturbo.com