Natural gas processing with RPI:
Sines Transgas Atlantico LNG Terminal
In October 2003 a LNG terminal for the vaporisation of imported LNG was commissioned at Sines, in the southwest of Portugal. The contractor for the erection of the LNG terminal was the Belgian Tractebel Gas Engineering, based in Brussels, who built the facility for the Portuguese Transgas Atlantico. The terminal itself comprises the ship unloading facilities, the sea water supply system, the process area and the general sections of the plant.
Figure 1: Sines LNG Terminal
The terminal is designed for an annual throughput of 5.2 billion m³ of natural gas. This corresponds to a supply rate of 600,000 m³/h. At peak periods this figure can be boosted to 900,000 Nm³/h.
LNG ships with capacities of between 35,000 m³ and 165,000 m³ can be unloaded at the terminal, for which purpose the unloading station is capable of a transfer rate of 10,000 m³/h.
Figure 2: Unloading facilities
The terminal also accommodates the loading of up to 3,000 tanker vehicles per year and an expansion to 6,000 tanker vehicles per year is already under consideration.
The plant features two storage tanks for the storage of the liquid gas, each with a capacity of 120,000 m³. The actual vaporisation takes place in five liquid gas vaporisers, each having a capacity of 180 metric tons/h.
Figure 3: LNG storage tanks
Natural gas is becoming of greater and greater significance as a source of energy and also as the starting point for petrochemical products. At 32-38 MJ/m³ (7,600-9,000 kcal/m³) its calorific value is very high and it can be conveyed in pipelines quickly and cheaply to the consumer.
Honeywell S.A. in Brussels secured the contract for the process control technology for this project. They employed the PlantScape process control system with control consoles in the process area, the sea water supply area and the unloading station.
Pepperl+Fuchs in turn received the contract for the interface level with the RPI System, involving around 1,460 signal circuits and an overall project value of over 300,000 €. A total of 28 control cabinets were equipped with RPI components by Pepperl+Fuchs and then integrated into the process control system consoles by the Belgian company Eni, the engineering contractor.
All the signal circuits are protected by Pepperl+Fuchs voltage protection barriers. The connection to the control system is via a redundant PROFIBUS. The control cabinets installed in Zone 2 each contain two redundant PROFIBUS lines. The physical connection of PROFIBUS to the control system is achieved with optical connections.
Figure 4: Control cabinet at the installation stage
Pepperl+Fuchs HART Multiplexers are used for the transfer of information from the intelligent HART Transmitters and HART Positioners to the system components. The HART transfer to the operation and monitoring stations is converted by a special Honeywell RS 485, LWL repeater for HART signals.
Power supply to the cabinets is via Pepperl+Fuchs power supplies, which are accommodated in separate explosion proof housings.
