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.

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.

Piping systems having service temperatures lower than ambient present a challenge for the pipe support design. Pipe supports for these cold piping systems are different from normal type of supports on pipes with service temperatures above ambient. Normally hot insulated piping systems have shoe type of supports directly welded to the pipe. In this case there is no relative movement between pipe support i.e. shoe and pipe while the pipe displaces due to changes in fluid service temperature inside the pipe. As the pipe expands when temperatures rise inside pipe, it displaces from its mean position of structural support. The shoe having been welded to pipe moves along with the pipe. On the other hand, shoe type supports on cold service pipes are not directly and permanently connected to pipe. This is due to the fact that the pipe insulation on cold service piping is designed to be seal tight so that outside air cannot get inside the insulation and reach pipe surface where it starts condensation. The condensation in turn causes corrosion issues. To avoid this moist air ingress inside the insulation, the shoes are made of clamp types and are placed outside the insulation cladding. This causes problem of clamp type shoe slippage on cladding and total displacement of pipe shoe from its structural support. This paper presents an engineering study of a piping system with cold fluid service (propane) where multiple supports had fallen from the structural supports or had dislocated considerably. At few support locations, cladding was found to be damaged and ice formation was noticed. In addition, many clamped shoes had rotated as shown in figure 1. The solution as outcome of study was simple, economical and easy to implement. A comprehensive study was conducted to identify the root cause of piping supports dislocation, displacement and rotation. The static/dynamic stress analysis of the piping system was carried out. The results revealed that the displacements in the piping system were not so high to cause the supports dislocation or high displacements of shoes. In addition, the stresses on the piping system due to the contraction of pipe upon cooling were within allowable limits. Figure 1Rotated and dislocated Clamp support on Cold Service Pipes As a part of study process, operation was enquired if any upset had happened which might have caused the dislocation and abnormal movement of pipe and hence transferred to its supports. Operations informed that there was no such incident and the line had been operating normally without any trouble. The process study including review of hydraulics, verification of line size and surge was performed to identify the root cause of piping abnormal movement. The process study concluded that line size was adequate and no surge scenario was identified for the line's concerned portion. So following reasons which could cause abnormal pipe movements and dislocation of supports were ruled out based on above study: Operation upset in the piping system (such as sudden opening or closing of a valve or sudden starting/stopping of a pump),Line sizing or surge flow,Contraction of line due to cooling of piping system or piping configuration. The next step in the study was to review the support configuration in detail. Study found basic design problem with the support configuration that was the cause of supports dislocation, excessive movement and rotation of clamped supports.