Malaysia’s ambitious Refinery and Petrochemical Integrated Development (RAPID) facilities owned by PETRONAS required the construction of residue fluid catalytic cracking unit (RFCC). For environmental protection reasons, carbon monoxide (CO) contained in flue gases from the cracking process needed to be turned into carbon dioxide; therefore, two massive CO boiler units were incorporated into the design.
The engineering, procurement, and construction (EPC) work of Package 1 RFCC project was contracted to CTCI, which used modularisation techniques to successfully shorten delivery time span by almost one-third and deliver the two heaviest boilers in the history of Malaysia across the sea to Pengerang Integrated Complex at Johor.
Building the boiler units in Malaysia would have required massive amount of manpower and machine mobilisation. To maximise cost-efficiency, the CO boilers, each 28 metres high, 35 metres long, 17 metres wide, and weighing about 2,000 tonnes, were designed and fabricated as modules before being assembled in a yard located near Kaohsiung Port in southern Taiwan, so that they can be easily shipped out once finished.
Modules are pieced together first by carrying out refractory lining work on the boilers’ side walls, followed by lifting side panels with five cranes to finish assembling the bottom of structure and side walls. After casing is completed, boiler tubes are then installed.
Traditionally, installing boiler tubes is time-consuming and not easy for inspection if one follows ‘layer-by-layer stacking’ approach. CTCI coped with this challenge by setting up a monorail system on top of the boiler casing, which allowed faster insertion of tube harps and made inspection much easier. Once the tubes were in place, the remaining steam drums and auxiliary parts were installed.
The next challenge is sending the extremely heavy boiler modules onboard the 8,000 tonnes RollDock vessel. To this end, three sets of self-propelled modular transporters (SPMT) were used to roll them onboard. An SPMT is a multi-axle transport vehicle with hydrostatic drive system, electronic/hydraulic multi-directional steering, and hydraulic elevating loading platform.
To ensure successful shipping operation of modules of this size, a couple of things must be kept in mind. First, carry out simulations beforehand, make all necessary calculations, and check necessary equipment. Second, check schedules, weather conditions, safety, sequences, fastenings at sea, etc.
During the voyage, use motion monitoring system to measure and record vessel motions to ensure the cargo motion stays within limits. And finally, before the vessel arrives at destination, check again the weather conditions and other restrictions before allowing an experienced in-land transportation provider to deliver the modules.
Lastly, precise schedule control at every stage was also a key to successful delivering the boilers ten months ahead of the 30-month schedule. This included precise installation timing, boiler shipment according to site requirements, and experienced staff assigned to supervise over the entire pre-assembly process. Fast responses from the client, the vendor, and contractor ensured work quality and technical control, bringing the boiler assembly and installation into fruitful success.
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