Jebel Dhanna/Ruwais, which encompasses the industrial complex of Ruwais, is situated on the Persian Gulf coast approximately 220km West of Abu Dhabi. The terminal is operated by ADNOC Onshore. The offshore facilities consist of three SPMs handling exports of crude oil. The port area consists of two main oil terminals, which handle crude oil and products for the refinery: a gas terminal, a bulk fertilizer terminal, a sulphur handling jetty, and a small cargo harbour.
We at Mechartes were engaged as engineering consultants to perform special studies, including CFD and FEA modelling, for various engineering applications. Our objective was to propose the technical viability of modifications to the existing crude tanks to accommodate an increase in True Vapor Pressure (TVP) from 11.1 psia to 14.9 psia.
For these modifications, we conducted comprehensive studies using CFD and FEA analysis. We provided design modifications to re-evaluate the roof design and compared it with other standard double-deck floating roof tanks using FEA analysis.
Additionally, we assessed the floating roof structural design requirements and limitations in accordance with API and other internal standards, specifications and practices. Through CFD and FEA analysis, we determined and derived the maximum TVP limits for existing tanks, both with and without modifications. Our study encompassed four tanks, including large and small tanks with double-deck and single-deck external floating roofs.
The Computational Fluid Dynamics (CFD) study was also carried out to demonstrate the flow distribution of produced water from the existing production separators and produced water sources discharging to the existing produced water system, which is revamped and upgraded as part of the scope with the addition of 30 MBWPD new produced water degasser, tank, pumps and disposal wells.
The CFD study demonstrated the multiphase behaviour of the produced water routed to the existing and new degassers in all operating scenarios, including start-up, normal operation, and shutdown. The study advised on the start-up sequence for optimum smooth distribution of the produced water in the system and the balancing of the existing and new disposal water tanks & degasser’s level and also demonstrated the droplet size distribution of oil in water and water in oil of droplet’s concentration against the droplet micron size which is both dictated by the below performance guarantees. The study was carried out for various separators in the project.
Furthermore, we carried out Flow Induced Vibration (FIV) and Acoustic Induced Vibration (AIV) studies, examining vibration fatigue induced by acoustic phenomena and fluid flows in all piping covered under this project, as well as all existing piping affected by it. We performed LOF calculations for each area for all the lines, following the guidelines from the Energy Institute.
Our AIV and FIV assessment methodology was based on the “Guideline for the Avoidance of Vibration Induced Fatigue Failure in Process Pipework” published by the Energy Institute.