GASCO (Abu Dhba Gas Industries Ltd) commenced design and construction of processing facilities since 1978. The main plants and subsequent expansions were engineered in phases by different EPC Contractors. Piping Material Specifications (PMS) were developed for each Project as per EPC Contractor’s engineering understanding and as per the Project need. This resulted in having different PMS for similar fluid services in an identical process Units/Trains. This paper presents the outcome of the study to optimize the number of PMSs and generate a common PMS to satisfy all the existing plant requirements. GASCO has around 800+ Piping classes across all the sites. The selection of right PMS was a challenge during the modification projects in existing plants. It was also difficult for Store/Ware house personnel to maintain the inventory and track spares as because of large number of stock codes. A comprehensive study was undertaken to develop a master set of PMS involving following steps; data collection & review, checking the compatibility with latest Codes and Standards, study lessons learnt, generate back up calculations, documentation and publish the Design General Specification (DGSs). Through this comprehensive study, 800+ piping classes were optimized to 150 number of piping classes in a common PMS to suit overall GASCO’s requirement. The co-relation of existing piping classes having outdated materials with newly developed classes made the selection of required piping class much easier and user friendly. The new PMS, with new material classes ensuring good engineering practices and adapting the lessons learnt over the years of operation. This optimization campaign facilitated GASCO to formulate a definitive approach towards the selection of common piping material for specific fluids across the plants. The new PMS has segregated the material requirement for various fluids with different operating temperature and pressure conditions from different Units/Trains. Some of obsolete components had been taken out from PMS based on GASCO’s operating experience over last 30+ years. The selection of material has become easy at all level of work force when doing the modification work. Use of right piping material will save material cost with engineered material solution with minimal failures. Alignment with all the Plants with common piping classes will maintain optimum inventory across GASCO plants. The same philosophy can be used within all the OPCOs under ADNOC directives of cost saving and standardization.

In OUR Gas Processing plants, steam is used as a heating medium in process reboilers and utilities. Condensate carryover induces water hammer in the distribution-piping network, causes pipe/structure dislocations, and creates serious risk to plant operations, safety and integrity. This paper presents the techniques to identify the root causes and mitigation measures to minimize such incidents and enhance energy saving opportunities in steam network. The existing steam generation and distribution network is huge with multiple plant interfaces due to brownfield expansions. A comprehensive analysis of integrated network for design, operation, maintenance and monitoring along-with detailed survey was performed. Gap analysis of steam system components was conducted to identify the improvements considering current standards and best practices. Detailed dripleg/trap adequacy checks, condensate load calculation, trap survey and steam quality check was performed. RCA reports were reviewed for causes of incidents and recommendations incorporated. Study revealed that optimized driplegs, steam trap types, insulation and monitoring program, reduces steam blow-off and enhances energy savings and plant performance. Analysis showed that existing network operates just above saturation temperature and lacks provisions to remove condensate and trap management needs improvement. For uninterrupted plant operation, bypass valves of failed traps were opened to atmosphere resulting in steam/condensate losses. Key findings are; Piping/structure not designed for hammering and should be avoided by minimizing condensate from source and removal during distributionSteam dryness is nearly 93% indicating >7% is condensate to be drained from steam system.Valve/flange insulation removed during maintenance not reinstated, accelerates condensate formation and energy loss.Reverse and bidirectional flow occurs; however, piping is designed for unidirectional flow.Slope not provided; however, modification to existing piping is not feasible.Dripleg/Steam trap interval >100m at many locations does not comply max.50m requirement and existing driplegs are undersized.Flanged connections are susceptible for steam leaks, should be minimized.Survey indicated that >50% steam traps are either blocked or blowing steam (passing).Thermodynamic traps predominantly provided in saturated steam systems are ineffective for actual condensate loads and blocked by corrosion particlesBlocked traps create water hammering. Steam leaks cause energy loss and damages supports, concrete paving and foundations Major recommendations are; For interconnected networks, maintain uniform temperature across all desuperheaters and provide driplegs / traps either side of expansion loops.Use float drain traps at desuperheater downstream and inverted bucket traps in distribution piping.For maintenance ease, utilize universal connector/compact trap valve stations.Replace failed traps immediately.Evaluate using cyclone separators to improve steam dryness. Develop trap database and conduct surveys through specialists Study recommendations being implemented in phases.

The rapid induction of Fiber Reinforced Plastics (FRP) into process industry due to high corrosion resistance and cost effectiveness made End Users to overlook FRP's specific design, fabrication and quality control aspects. This also affected various Utility and firewater networks in ADNOC Gas Processing plants. It is addressed by enhancing Vendor pre-qualification, relevant specifications and construction procedures. This paper presents measures adopted to ensure reliable design, supply and installation of FRP piping systems. FRP piping systems have unique design/construction requirements that was not followed in totality in AGP past installations. Also, international standards do not offer adequate guidance on design, resins selection, fabrication methods and joint systems. Vendors were trusted upon for complete design. A campaign is initiated to engage FRP pipe manufacturer having binding single point responsibility from beginning of project for particular FRP system design to ensure desired performance of FRP piping system with extended warranty. Measures have been taken to improve quality material supply through enhanced vendor pre-qualification, ADNOC Gas Processing specifications and CONTRACTORS pre-qualification having certified site crew. Studies revealed that material quality, velocity/surge pressure were the main contributing factors for failures which were not adequately addressed in design of FRP piping systems. Gaps noticed in previous projects were use of inadequate Codes, Composite's mechanical properties, design approach, inadequate joint preparation and QA/QC in construction phase. During manufacturing using wrong resin can be a cause for premature failure. Absence of certified personnel for project execution and Non-compliance of manufacturer's instructions were also key lapses noted in construction phase. The gaps in design process, necessitated improvement and consolidation of ADNOC Gas Processing existing design specifications/criteria and analysis requirements which now mandate that the required hydraulic / surge / static analysis shall be carried out by pre-qualified FRP manufacturer. Material property issues were addressed by clearly specifying the material composition & properties requirements and procedural requirements for storage are incorporated into the manufacturing process, along with mandating minimum prior experience for the manufacturers for material supply and design. Certification of contractor's personnel and presence of FRP manufacturer's representative at site during construction and pre-commissioning has been emphasized as mandatory requirement. In addition Specialist 3rd party inspection/supervision must be deployed to ensure quality control during every step of construction and commissioning Design specifications, procedures, manufacturing process, QA/QC and installation methods for FRP piping systems are available, but lacked activity interface between consultant, vendor and contractor. ADNOC Gas Processing enhanced the FRP specification ensuring single point responsibility with Vendor and procedures to ensure consistency from the design phase coherent with manufacturing process and appropriate implementation during the execution phase, in order to ensure the safety and integrity of FRP Piping systems.

Limitations in Amine storage capacities at one of GASCO's Plants necessitates the use of temporary ISO-Storage containers to store surplus Amine during Plant / Process shutdown. This poses serious risks to equipment and personnel safety which could be categorized as a safety critical issue. This paper addresses the study carried out to resolve the issue, exploring various options and how the proposed solution mitigates the risks and ensures process safety by enhancing operational flexibility of the amine unit. Optimization of the Plant layout for HSE constraints resulted in location of amine regeneration section farther away from the amine unit, leading to an increase of solvent inventory above design levels. As a result, during shutdown operations, the existing storage capacity was deficient by a significant margin, necessitating use of temporary facilities to overcome the shortfall. A study was carried out to find solutions to the issue and various options were explored. Limited availability of space in an existing Plant, working within hazardous area and tie-ins with existing processes posed several challenges. The entire study was carried out utilizing GASCO's in-house resources involving full spectrum of discipline engineering expertise. The selected option involved provision of an additional storage tank and associated facilities. This included identification of the required tank sizing and storage capacity, feasible location of tank and transfer pump, feasibility study of pipe routing and tank bund containment calculations. The following benefits will be achieved with the proposed solution: - Safe access for operation/maintenance. - Proper containment of spillages / leakages within the tank bund. - Nitrogen blanketing to stop H2S release and reaction of lean amine with oxygen. - Venting (routed to a safe location). - New lean amine tank will have fixed firefighting foam system. - Use of fixed 6 inch line instead of hose for lean amine transfer. - Shutdown delays will be avoided. - Process contamination will be avoided. As the proposed location was within the hazardous area close to live Plant units, tank installation was required to be carried out within the shutdown period. This triggered the development of a novel approach for a modular fabrication of tank, transportation in parts and installation strategy, to maximize pre-shutdown activities and enable optimum use of shutdown duration for the installation. Accordingly, study addressed this concern through extensive interaction with tank fabricator and recommended suitable methods. Modular fabrication and installation of a new tank within live process units to ensure reliable and safe operations, is a novel approach to addressing the solvent storage issue. This approach will also avoid delays and extended shutdown duration.

Compressors are an essential component in Gasco's plants that transfer enormous energy to process fluids in the form of pressure and velocity. Conventional process and piping design are based on consistent / steady operating parameters and at times designers overlook the possibilities of sudden changes in process parameters. Operating conditions are sometimes altered as part of capacity/performance enhancements. These changes result in difference between design and operating conditions of the compressor which can also impact associated piping systems. In one of Gasco's plants, abnormal vibrations upstream of anti-surge valve piping at Expander-Compressor, were observed. Sustained vibrations are a threat to critical inline instruments and mechanical components thereby posing integrity risk and potential Loss of Process Containment (LOPC). LOPC can have significant impact not only to process, personal and environment safety but could also lead to production loss with impact on business and reputation. This paper addresses the study carried out to identify the root cause of vibration, and the remedial measures recommended and implemented to mitigate the risks due to piping system vibration. An exhaustive multi-discipline investigation was carried out comprising of site visits, data collection, detailed review of existing documentation, as-built conditions and current operating parameters. Process and control system review did not indicate any abnormalities. In addition, piping vibration induced due to compressor or anti-surge valve operation was ruled out as cause based on design review of anti-surge valve and expander compressor/turbine. Piping system review concluded that inadequate pipe supporting was the primary reason for piping vibration. Comprehensive Stress Analysis (static and dynamic) was conducted to determine the modifications required to mitigate vibrations. The stress analysis accounted for actual operating cases in addition to the design conditions. Based on stress / vibration analysis, pipe support modifications were proposed to make the piping system adequately rigid and minimize vibration. This resulted in increase of system's natural frequency while ensuring that the stresses are within permissible limits. Proposed modifications were designed for implementation without the need for shutdown. Post implementation, piping Vibration were reduced drastically and were found to be within acceptable limits specified in Energy Institute guidelines. This has resulted in increased personnel safety, reduced environmental and operating risks, reduced downtime and failures, and preservation of company assets and reputation. Due to the criticality of the process / equipment and non-availability of near term shut-down window, the main challenge in this exercise was to provide modification solutions which can be implemented while the compressor / plant is online. Innovative approach to design of support system utilizing in-house expertise, and continuous support during implementation are key takeaways from this project.