Design Tips 17

FPSO/ SemiSub

• Motion: Affects performance. Separated oil and water may merge if internals do not consider pitch. Liquid level swings affect alarm/trip setting and column performance. CDD elevation may momentarily go up w.r.t to source. See ‘Hazards - FPSO’ in Training

• Layout: Locate long separators and columns close to centre to minimize movement (3 axis) impact on level settings and performance

HAZOP

• Missing pre-Hazop joint review by operations and design leads to poor Hazop. Pre-review comments and contractual issues should be settled ahead. This avoids stalled discussions and teams digging into trenches with a not to yield attitude. Design team knows steady state issues and handles the project for a year. Operations will run it for 20 years and have better insight on transient or start-up issues

• Scribe: Best asset - one who captures on his own essence of discussion + right tag numbers etc without prompting. Frees the team to keep the momentum without dragging the discussion into a drain

• Capture design improvements as observations and assign to owners so that any EPC cost implications can be settled later

• Avoid prescriptive recommendations. Keep it open. Recommendations are NOT mandatory. Review team can provide the best possible solution, based on intent

Petrochemicals

• C2= Plant: Brittle Fracture. Consider (1) Loss of heating medium (2) Autorefrigeration on pressure loss and (3) autorefrigeration followed by repressurization