Shutdown and Blowdown Valve Applications
Avoiding Pressure Surge Damage in Pipeline Systems - Pressure surges occur in all fluid pipeline systems. There arise two types of damage from the surge phenomenon, fatigue and catastrophic failure. This paper addresses this phenomenon from the viewpoint of the available solutions rather than the mathematics and modelling involved in determining the quantum of the surge pressure. it has some useful information pertaining to SDV/BDV valves- from Piping Design.
Redesign Blowdown Systems and Alter ESD Practices - When compressor stations are taken offline for maintenance or the system shuts down, the gas within the compressors and associated piping is either manually or automatically vented to the atmosphere (i.e., blowdown). Emergency shutdown (ESD) systems are designed to automatically evacuate hazardous vapours from sensitive areas during plant emergencies and shutdowns. Some ESD systems route these vapours to a flare stack where they are combusted, while other systems simply vent the evacuated vapours to the atmosphere via a vent stack. Partners report a number of opportunities to reduce emissions from blowdown systems and ESD practices, including (a) Redesigning blowdown systems altering ESD practices (b) Installing YALE® Closures (c) Designing isolation valves to minimize gas blowdown volumes (d) Moving fire gates valves in to minimize blowdown volumes. Department of Transportation (DOT) regulations require that emergency shutdown (ESD) systems at gas compressor stations be fully tested on an annual basis. One common practice is to activate the entire system, which discharges very large volumes of gas to the atmosphere. A DOT acceptable alternative is to test each individual dump valve with the discharge stack blind flanged. This greatly reduces gas emissions, but has higher labor costs associated with installing and removing a blind flange on each ESD valve - from the EPA.
The Following are from Metso Automation
Need a Cryogenic Valve Testing Facility? - The cryogenic valve test centre at Metso Helsinki factory is one of the largest and most advanced dedicated valve test facilities in Europe. It offers customer inspectors the possibility of witnessing potentially hazardous testing operations through shockproof windows in the comfort of a protected, air controlled control room built to the latest safety standards, using a fully computer controlled and logged testing system.
Gas to Flare System ESV & ESD Valves - Both ESD and ESV valves are commonly located in or near the process plant. The flows from different proc¬esses are further lead to a flare header which is sized for the certain worst-case volume condition, assuming that relief devices discharge at the same time and other process vents may also be flowing.
Atmospheric Distillation ESD Valves - Atmospheric distillation is the first major process in a refinery. All crude oil entering the refinery, after desalting, passes through the atmospheric distillation column on it’s way to further processing in down stream process units. If there is a shut down of the atmospheric distillation column it means that the entire rerfinery is essentially shut down. The ESD valves are located at the bottom of the atmospheric distillation column and are typically arranged as two valves in parallel piping. The fluid passing through the valves is refered to as heavy bottoms. This fluid is the heaviest cut of a hydrocarbon attainable by atmospheric distillation. The heavy bottoms pass through the ESD valves on their way to the vacuum distillation column for further processing. The ESD valves are used in the normally open condition and are expected to function reliably throughout long process runs, typically four (4) to five (5) years between shut downs.
Oil Refinery and Other Units Processing Hydrocarbons - ESD valves with High Integrity Level - There are fire and explosion risks in the units processing flammable hydrocarbons in case the fluid comes in contact with the atmosphere. If there are high- and low-pressure sections in the plants like e.g. in refinery HDS (hydro desulphurisation) units, the low-pressure side has to be protected against high pressure in case of control failure. Traditionally the number of emergency shut-off valves (ESD) in the process lines in a refinery is not very high. With Neles ValvGuard’s partial stroke testing functionality the ESD valves are automatically diagnosed for their operability while the plant is in operation. With this technology general plant safety can be improved in a cost effective way.
Reliable ESD Valves in Tower Bottom Lines in Heavy Oil Units - Besides fired heaters, the distillation tower bottom areas are the most fire-risky places in a refinery. When the question is of residual oils, high oil temperature, coke formation, sulphur corrosion and possible particles in the oil make the conditions even more severe. Neles metal-seated ball valve with its constructional features and the Neles ValvGuard, partial stroke testing system, used to keep the valves under continuous watch are helping to minimize the fire risks in these areas.
High-End Intelligent Emergency Valve Applications - Jari Kirmanen - Process facilities today are facing growing challenges to meet requirements with respect to the environment, health and safety of the plant personnel while maximizing product output and quality. With increasing energy prices, process plants must further develop their processes and maximize the yield of valuable products in an energy-efficient way. Plant run-time targets are increasing, which also set more challenges on equipment reliability and safety. De-pressurizing or pressure protection, as well as burner emergency shut-off being part of the safety integrity system, is a part of the process industry’s backbone defence against a threat to personnel and equipment. Intelligent partial-stroke devices capable of diagnosing emergency valve condition are more commonly utilized in the hydrocarbon industry. General requirements and challenges together with the benefits of using emergency valves equipped with intelligent partial-stroke devices were considered in the Hydrocarbon engineer magazine article in November 2009 [1]. This article demonstrates more closely how intelligence solutions can be utilized and what kind of added value they bring by introducing three examples of high-end emergency valve applications
Intelligence for LNG Ball Valves - Intelligent valve technology can help to reach the most demanding targets in anti-surge control applications, where fast and accurate operation is needed at extreme service conditions with high pressure differentials and tight shutoff.