Publications

The Belanak Floating Production Storage Offloading (FPSO) vessel is located in Block B in the South Natuna Sea, Indonesia and uses 3 molecular sieves as the dehydration unit which is based on a solid bed desiccant system using 3 dehydration beds on staggered drying and regeneration cycles. Each Molecular Sieve Dehydrator Bed is designed to dehydrate 263 MMSCFD of sweet feed gas, at 750 psig and 88 to 120°F, to less than 0.1 ppmv. This bone dry gas outlet molecular sieve is required to avoid hydrate formation in the gas plant which is located downstream of the molecular sieves unit. Originally, the molecular sieve was designed to only remove saturated water but was then modified to help to handle mercury in the gas phase as well. Combining 2 types of adsorbent in the molecular sieve proved to help to extend the adsorbent replacement time of the upstream Mercury Removal Unit (Mercury Guard Bed). The risk and costs associated with replacing spent adsorbent are also high. Adjusting the process condition, regular performance tests & continuous process surveillance have been applied to extend molecular sieve lifetime. The existing unit has now already been functioning for 5 years. Keywords: Belanak, molecular sieve, dehydration.