Tank containers are designed for an economic life of typically 20 years. During this life the tank is used over and over again. After discharge of cargo the tank is cleaned, inspected and prepared for the next cargo load.
A tank container engaged on long-haul trades, for instance China to Europe, where the door-to-door voyage lasts about 6-7 weeks, might ship up to eight loads annually. Over 20 years, that amounts to 160 loads or 4,000 metric tonnes of cargo. Short-haul trades will result in considerably more loads.
The tank operates door-to-door. It is loaded with cargo in plant A and transported by truck, rail and ship to the destination plant B where the tank is unloaded and the cargo directed into the production process.
Tank containers are manufactured of materials that are very suitable for re-cycling.
The total weight is typically 3,700 kg, of which the majority is metal, namely the stainless steel tank and the carbon steel frame. These are easily cut into manageable dimensions that can be melted and made into new materials.
To extend the life beyond 20 years, tank containers often undergo re-manufacture.
This starts with the removal of the entire tank frame and insulation, retaining only the stainless steel tank vessel, valves and fittings. Stainless steel is a long lasting metal; it is highly suitable for re-use.
The re-manufacture process re-cycles the retained tank into a new frame. The tank is reinsulated and tested and continues its service life as new. It is expected that this process will extend the life of the tank a further fifteen years.