The oil and gas producing and processing industry is unique in that many of its facilities are not land-based factories. The processing schemes are very similar to land based factories, but the need to build the factories in the water is unique. Structural engineering and construction engineering costs are much higher, simply because there is no soil to hold the complex up out of the water.

There have been several publications on different methods to reduce and manage weight of these facilities by optimizing the equipment or structural design. These include larger turbo-machinery (allowing one unit to perform the task of two), combining two valves into one body (allowing weight reduction where double block and bleed isolation is required) and the use of High Integrity Pressure Protection Systems (HIPPS). However, a literature review shows that there is very little work published on how process engineers systematically synthesize a process flow scheme with a view to weight reduction. Process integration offers one possible method to obtain weight reduction.

This paper examines some process integration issues and techniques in an effort to systematically reduce weight, using two case studies of different feed composition to support the findings. Three areas were investigated, ranging from very simple utility modifications to managing turbo-machinery exergy.

For the case where the feed gas had a relatively low condensate component (lean gas), minor utility modifications and aggressively managing energy transfer across the process and utility pinches reduced equipment list weight by 22%. For the rich gas example, the same methodologies reduced equipment list weight by 6.5%, with potential for further reduction up to 9.5%.

This paper is a summary of the work of Westover1.

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