With focus on enhancing Integrity and efficiency, ADNOC Gas Processing identified an opportunity for optimization of existing FRP firewater system in Ruwais. A comprehensive study of complete firewater network and review of operating and control philosophy performed in order to optimize the system performance and mitigate pressure surge problems. This paper presents measures that ADNOC Gas Processing have adopted to achieve improved system efficiency and lower operating cost. A study was undertaken by GASCO to review issues with existing Fire Water network (FWN) at Ruwais to enhance overall performance of system in terms of design, operation and control. Initiative was to identify problems, evaluate root cause and think of optimization including some cost saving solutions. Study explored various operating configurations of existing 4-working+ 4-standby pumps with active involvement of operation personnel followed by hydraulic and surge analysis with different operating scenarios. Study revealed reduction in flow, head and pressure to mitigate fire water piping surge problems. Study also engaged pump vendors to establish feasibility of modifying the existing pumps. The study identified that each existing fire water pump is suitable to deliver 1400 m3/hr against required flow of 1000 m3/hr. Additional flow may create pressure spikes and surges in FWN. Hydraulic analysis found that pressure was above minimum requirement of 7bar (g) at the most remote point in network. Simulation indicated that fluid velocity was above 3.5 m/s at specific sections on the ring main. Increase in pipe sizes is required to arrest velocity within recommended limit in these areas. Option of lowering the operating pressure of main fire water pumps without the fire water network pressure falling below 7bar (g) at the most hydraulically remote point in the network was studied. Also the option of 3W+3S and 4W+4S [working (W) and standby(S)] pumping configuration was studied so as to establish that system can work with less number of pumps. Hydraulic study concluded that rated pressure should be reduced along with shut-off pressure. The maximum worst case fire water demand is 3200 m3/hr. The demand is found to be achieved with three Fire Water Pumps. During study pump vendors were engaged to arrive at the conclusion that 3W+3S configurations are hydraulically acceptable with pump / impeller modifications and de-staging options.

ADNOC Gas Processing (AGP) plays a strategic role in ADNOC and the UAE hydrocarbon value chain by contributing significantly for the development of the Emirates. AGP operates and manages an integrated Pipeline Network of approximately 3200km length of Pipelines with the mission of uninterrupted supply to its Customers without any impact on the upstream plants. Various fluids are transported via pipelines such as Sales gas, Crude oil, NGL, Condensate, Water, Nitrogen and associated gases wherein majority of network contains Sales Gas. Pipeline Network is scattered over Ruwais, Habshan, Buhasa, Asab, Shuwaihat, Jebel Danna, Al Maqta, Taweelah, Jebel Ali, Al Ain, Ghantoot, Al Dhabbaya, Al Romaitha, Saadiyat Island, Yas Island, Mussafah and in some other areas within the Emirate of Abu Dhabi. The Sales gas pipeline network connects gas plant facilities to consumers/ADNOC Plants through pipeline Distribution Facilities (Manifolds). The NGL pipeline network connects NGL plant facilities with manifolds to onward supply of NGL to AGP plant for fractionation into various products such as ethane, butane, propane and naptha etc. These manifolds are old and highly critical, hence their safety and reliability are paramount to ensure shareholders commitment to various consumers in UAE and abroad. Failure of these manifolds will have a major impact on upstream & downstream production chain. Shut down of these manifolds are not possible as there is no bypass arrangement or back up manifold for business continuity. Failure of any of the manifold will have major impact on AGP Business and reputation. Some of theses manifolds were constructed in late 70’s and have completed their design life. In line with current business scenario and fit for purpose approach being adopted by ADNOC, it is prudent to understand methods to assess the condition of existing ageing assets and apply techniques to enhance the reliability and integrity of the same. Ageing equipment is challenging and a systematic approach is necessary to decide on the life of ageing assets. AGP is one of the largest gas processing companies in the world, and it is considered as the major energy and feedstock supplier for the majority of the power, hydro carbon, and petrochemical industries based in the UAE. In view of the above, AGP has carried out an Integrity/Adequacy assessment study to check fitness for service of the manifolds with due consideration to business continuity, the impact on upstream/downstream production, Company reputation, asset integrity, process safety and HSE aspects etc. This paper presents the challenges faced and best practices adopted for ensuring/enhancing Process Safety (Prevention of Loss of Containment), improve integrity/reliability of the manifolds, minimize impact on normal operation and maintenance and reduce the risk of business interruption. AGP best practices are based on the requirements of Pipeline Codes, International Standards, industry practices, ADNOC Gas Processing Specifications/Standards, and good engineering practices etc. The Best Practices followed in this study have ensured the safety, efficiently and reliablty of operation of these manifolds. Confidence level in assuring integrity of againg facilities is boosted. Similar approach will benefit the oil and gas industries for ensuring safety and integrity of old ageing facilities.