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 The co-relation of existing piping classes having outdated materials with newly developed classes made the selection of required piping class much easier and user friendly.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.

The paper reports the frequencies of the different modes of vibrations of the tymbal in cicada theoretically. The two-dimensional wave equation in elliptical coordinates is set up. Since the tymbal is elliptical the solution of the modified Mathieu's equation is considered. In order to obtain the different frequencies the pulsatance equation is used. The study suggests that elliptic membrane produces

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.

Ideal process/piping design is based on consistent and steady operating parameters. Sometimes these parameters varies significantly due to capacity or performance enhancements during operation. These flow changes from an ideal design to actual operating conditions are often resulting in flow induced vibrations. Excessive Vibrations in piping systems pose potential threats to plant safety and integrity. This paper presents the challenges to mitigate flow induced piping vibration due to multi-phase flow in rich amine systems with successful measures. A comprehensive study was conducted to identify the root cause for piping vibration in rich amine piping system (20″ pipe) from plate type heat exchanger to amine regenerator. The vibration measurement was carried out where the vibrations are visually high. The vibration screening and likelihood calculations were carried out based on Energy Institute's guidelines and those were identified in concern/problem zones. The process study including the review of hydraulics and piping stress analysis was carried out with actual operating conditions. The multiphase density/forces was simulated to identify root cause and to propose suitable recommendations for mitigation of piping vibration. Process study reveals that the fluid flow type is multi-phase where the sudden pressure drop occurs at control valve. The flow regimes were reviewed along the section of pipe to identify the major flow turbulences. The alteration in the operational modes shall reduce the impact of load due to slug flow and shall minimize the vibration. But, since it results in loss of energy, it was suggested to provide adequate piping supports to mitigate the piping vibration. Static/dynamic piping stress analysis reveals that the piping system needs better supporting arrangement to cater slug loads conditions. The natural frequency of existing system was calculated and found to be low with existing supports. The design of existing supports was reviewed and accordingly suggested suitable additional supports such as holddown and axial stop to increase the natural frequency of piping vibration. Since the piping vibration source is control valve where there is sudden change in pressure, the guides and axial stop restraints were proposed to control lateral/axial movements by keeping the stresses in safe limits. The proposed modification were implemented while plant is in operation. The post implementation vibration survey was carried out and the readings were found to be within acceptable limits. The challenges such as balancing the stresses in piping system with appropriate minimum natural frequency levels to make system rigid enough and implementation of proposed modifications without shutdown were successfully achieved. The novel information from this study is, by identifying exact root cause of piping vibration, it is easy to mitigate the same from source level by application of best design/analysis practices with successful measures.