For heavy oils and other liquids

Independent terminal networks like Oiltanking perform vital connecting services between the oil fields of the world and the users of derivative products. Independent storage terminals are those which are not owned by the clients they serve and do not own any of the products they handle. Oiltanking’s clients include private and state oil companies, refiners, petrochemical companies and traders in petroleum products and chemicals.

Established in 1989, Oiltanking Malta is jointly owned by Oiltanking GmbH of Hamburg and the Malta Freeport Corporation. It currently has 19 tanks, spread over three sections at its site at the mouth of Marsaxlokk. These tanks can hold more than 361,000 m3 of oil in total. All the company’s capacity is contracted to third parties, which use the facilities to store and transship oil. The three new tanks in Tank Field 4, representing the first phase of expansion in this area, will provide extra capacity of 90,000 m3. Once the full expansion of the terminal is completed and Oiltanking Malta’s facility has attained its full potential storage capacity, clients will benefit from more than 526,000 m3 of storage space. Centrally located in the Mediterranean close to the main shipping lanes between Europe, Africa, the Middle East, the Pacific Rim and the US, the terminal will thus further enhance its important role as a hub for the oil-related business.

Bartec was awarded the order for the engineering and supply of the trace heating for Tank Field 4. The heating has become necessary because heavy oils from transport ships are pumped into large tanks, stored and distributed there. In this case, the trace heating system had to heat the pipes and pump stations permanently at a holding temperature of 65 °C in order to maintain the pumpability of the product. A performance of up to 55 W/m pipe was required in view of the large nominal widths of the pipes between the tanks. Moreover, as the distance between the tanks was quite substantial, mainly single-core plastic pipes were used for the heating. The single-core EKL heating cable that was chosen has a fixed resistance with high flexibility to facilitate assembly without any problems. Due to its properties, it is ideal for heating piping, pumps, valves and containers. The heat conductor is a resistance wire made of nickel plated copper or copper alloy. The protective sleeve of the EKL heating cable is a high-quality PFA, which offers reliable protection against corrosion and mechanical strain. The reinforced structure ensures that the cable can be used even under increased mechanical stress and exhibits good chemical resistance. The EKL heating cable is certified for applications in hazardous areas. Fourteen kilometres were integrated at Oiltanking Malta.

Each heating circuit was equipped with a controller and a limiter because the tank farm was classified as a hazardous area. The combination of a 16 A Ex temperature controller and a temperature limiter ensures on the one hand that the desired temperature of the heating pipes is maintained and on the other that the maximum permissible surface temperature of the heating circuit is not reached or exceeded. The devices are change-over controllers housed in an EEx e certified polyester enclosure. The principle of the devices can be summed up as follows: Any change in temperature at the sensor bulb causes a change in the volume of fluid in the measuring system, which in turn results in a movement of the diaphragm membrane. This membrane is connected to a mechanical device that activates a microswitch. If the temperature at the sensor bulb exceeds the preset value, terminals 1 and 4 are opened. The limiter device locks out permanently if the set temperature is exceeded. If the temperature drops to about 9 % below the set value, it can be reset manually. In the event of a rupture or break in the sensor tube (leakage), the switch remains permanently open (fail-safe). If the temperature falls below the minimum setting, the auto control opens the circuit but closes again as soon as the temperature rises.

For explosion protection reasons, up to eight layers of cables were assigned to the pipe to prevent the output power of the heating conductor from generating an impermissibly high temperature which, in turn, could reach or exceed the limit for temperature classes T1 to T6 in hazardous areas.

Since all equipment related to the heating pipes also has to be certified for applications in hazardous areas, there were two options for connecting the EKL heating cable: The D connection sleeve and the Plexo connection system. The D connection sleeve boasts good chemical resistance and establishes an electrical connection between single-core EKL heating cables. The permitted maintenance temperature range is a maximum of 170 °C (depending on the current load). The maximum permissible total current is 20 A. On the other hand, Plexo, the first plug-in connection system for heating cables used in potentially explosive atmosphere, offers substantial reductions in installation time and expense. Maintenance work for future modifications of the heating circuit can be carried out more efficiently. The connection system is well suited for single-core, synthetic EKL heating cables. The heating and power supply cables are connected via safe springs that create the required pressure and avoid any need for unravelling or twisting. A sophisticated sealing system offers secure and reliable protection against adverse weather conditions. The system’s flexibility allows direct connection of the heating cable to a supply cable or an Ex junction box. Two similar heating cables can be joined together by means of a spliced plug-and-socket connection sleeve. The remote termination of the heating tape can be equipped with plug-in contacts to facilitate future extensions to the heating circuit. The multiple advantages of Plexo ultimately convinced the client. The connection system perfectly matched the specification for the application at Oiltanking Malta.

Hall 10.2, Booth F19

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