Valves for power generation
Valves for power generation with technical advice from a specialist
The working principle of valves for power generation
Valves for power generation cover the steam, feedwater, condensate, flue gas and bypass circuits of a plant, where availability is the dominant requirement. With valves for power generation the difference between a good and a mediocre solution often sits in details that do not show on a drawing. We find that questions about valves for power generation almost always come back to the same three points: medium, temperature and required tightness. A desuperheater injects water into the steam flow to bring temperature back to just above saturation, where atomisation quality determines the result. A turbine bypass routes steam around the turbine during start up and on a trip, and that valve has to handle a large duty within seconds. Steam is a demanding medium because pressure and temperature rise together and the medium can change phase within the same line. On valves for power generation we always check the full operating envelope, including start up and shutdown. For valves for power generation this means that construction and operating conditions cannot be judged separately. How valves for power generation behaves under varying load says more about the quality of the selection than behaviour under steady load. An emergency stop valve shuts off supply in a hazardous situation, and closing time there is a safety parameter rather than a comfort requirement. On a boiler, blowdown valves control the salt content of the boiler water, with continuous blowdown for fine control and periodic blowdown for sludge at the bottom. Anyone looking into valves for power generation quickly runs into a choice that goes beyond picking a catalogue number.
Material, seat and construction on valves for power generation
Pressure and temperature rise together in these circuits, which drives selection towards alloy bodies and hardened trim. That principle explains why valves for power generation behaves differently from a standard execution under heavier duty. We regularly see that a small change in the execution of valves for power generation makes a large difference to maintenance frequency. Thermal cycling from start up and shutdown fatigues seats and packings faster than continuous operation does. A pressure reducing station brings steam pressure back to the level the consumers require and holds that pressure stable under varying demand. Condensate carried along in a steam line causes erosion and water hammer, and both attack a valve faster than the steam itself. In superheated steam the temperature sits above saturation, and soft seats and ordinary packings are then no longer usable. With renewable generation on the grid, conventional plants cycle far more often than they were originally designed for. On commissioning we record set pressure, closing time and test results, so the plant can be shown to run within specification. PRUSS is strongly represented in this segment with valves for steam, boiler, turbine and gas turbine duty. In practice we find that most failures around valves for power generation come not from the material but from a wrong assumption during selection. Operating conditions govern the service life of valves for power generation far more strongly than the nominal figures on a datasheet.
Valves for power generation in demanding installations
They are used in power stations, combined cycle plants, waste to energy installations and industrial cogeneration. In process industry steam is used for heating, stripping and sterilisation, and each of those duties sets its own requirements. Boiler houses, combined heat and power plants and district heating together form the largest application area for these valves. On project supply we record per position which execution of valves for power generation was delivered, including materials and tests. The application range of valves for power generation runs from simple utility duty to heavy process plant, with a corresponding difference in execution. Demand for valves for power generation reaches us mainly from projects where the standard range falls short. On replacement we always check the existing installation dimensions for valves for power generation, so the pipework can stay untouched. In power generation these valves sit on the critical paths around boiler and turbine, where downtime costs money immediately. Our customers work in chemicals, petrochemicals, pharmaceuticals, power generation, offshore and in hydrogen and ammonia projects. Dutch Valve Vision operates under a KIWA ISO 9001 certified quality system, which in the RFQ stage of chemical and offshore projects is usually a hard requirement. For valves for power generation the sector determines which documentation and tests belong with the delivery. We see demand for valves for power generation rising in hydrogen and ammonia projects, where tightness requirements are high.
What we look at when selecting valves for power generation
If a simpler type will do the job, we say so on valves for power generation, even when that means a smaller order. Material selection for steam moves towards alloy steel with hardened trim, because erosion and thermal cycling weigh heaviest. A steam test device makes it possible to test the operation of safety valves while the plant stays in service. For safety functions we record the required closing time and fail position explicitly in the order. On valves for power generation we check that the actuator is sized on torque at maximum differential pressure and not on an average value. The required leakage class often drives the choice around valves for power generation more strongly than the budget does. Standardising across several positions makes valves for power generation simpler in maintenance and in spare parts management. For valves for power generation total cost of ownership weighs more than purchase price, certainly when replacement has to happen during a shutdown. On steam we always advise a condensate drain upstream of the valve, because it is the cheapest life extension available. Insulation around a steam valve should leave the actuator clear, because overheating of the actuator is a common cause of failure. Please also state the connection standard, the required leakage class and any project requirements such as NACE, PED or ATEX. Where there is doubt about valves for power generation we quote two executions side by side, with the trade offs stated explicitly. The cleaning and flushing procedure counts too on valves for power generation, because it can be more aggressive than the process itself.
Your enquiry for valves for power generation at Dutch Valve Vision
We supply valves for power generation as a loose product or as a fully assembled unit with actuator and accessories. Dutch Valve Vision supplies special valves for special applications from its base in Monster, the Netherlands, with QUADAX and PRUSS as the core brands in the programme. For repeat orders of valves for power generation we record the configuration, so a follow up delivery is identical to the first. Our specialists are happy to discuss valves for power generation on the basis of your P&ID, your datasheet or simply a photograph of the situation. We handle an enquiry for valves for power generation on its technical merits rather than as a price request that only produces a number. On repeat orders we record the configuration, so a follow up delivery is identical to the first and installation holds no surprises. Lead times depend on the execution, because a standard size from a running series behaves very differently from a valve in an exotic alloy with NACE certification. Documentation on valves for power generation has to be the kind a buyer or inspector accepts without discussion. We record which execution of valves for power generation was delivered, so a follow up delivery or spare part matches exactly later on. We keep the configuration data for valves for power generation on file, which saves a great deal of searching if a fault occurs later. Even when the specification for valves for power generation is not yet finalised, you can bring the question to us. On valves for power generation we come back with a proposal that explains why we recommend a particular execution. Bring us your question at sales@dutchvalvevision.com or +31 (0)70-2210560, even when the specification is not finalised yet.
Frequently asked questions about valves for power generation
What exactly does valves for power generation mean?
In superheated steam the temperature sits above saturation, and soft seats and ordinary packings are then no longer usable. An emergency stop valve shuts off supply in a hazardous situation, and closing time there is a safety parameter rather than a comfort requirement. A desuperheater injects water into the steam flow to bring temperature back to just above saturation, where atomisation quality determines the result. Steam is a demanding medium because pressure and temperature rise together and the medium can change phase within the same line. We see this come back regularly in enquiries about valves for power generation, and the answer is rarely a single sentence. This is one of the points on valves for power generation where suppliers differ most clearly from one another. We approach valves for power generation from the question of what the plant has to do, not from the question of what happens to be in stock. Alongside QUADAX and PRUSS we represent Pibiviesse, Schroeder, Striko, Malbranque, Daume, FluoroSeal and Guichon, so we can select the right brand for each project.
Which executions of valves for power generation are available?
A turbine bypass routes steam around the turbine during start up and on a trip, and that valve has to handle a large duty within seconds. Pressure and temperature rise together in these circuits, which drives selection towards alloy bodies and hardened trim. PRUSS is strongly represented in this segment with valves for steam, boiler, turbine and gas turbine duty. With renewable generation on the grid, conventional plants cycle far more often than they were originally designed for. If you are unsure about this on valves for power generation, we are glad to put the question alongside the actual process data. On valves for power generation we include start up and shutdown, because that is where the heaviest loading occurs. The balance between required tightness and available operating force is a recurring tension on valves for power generation. Our customers work in chemicals, petrochemicals, pharmaceuticals, power generation, offshore and in hydrogen and ammonia projects.
Which materials are used for valves for power generation?
On a boiler, blowdown valves control the salt content of the boiler water, with continuous blowdown for fine control and periodic blowdown for sludge at the bottom. Thermal cycling from start up and shutdown fatigues seats and packings faster than continuous operation does. Condensate carried along in a steam line causes erosion and water hammer, and both attack a valve faster than the steam itself. A pressure reducing station brings steam pressure back to the level the consumers require and holds that pressure stable under varying demand. The answer to this question on valves for power generation changes as soon as the medium or the temperature changes. In most projects valves for power generation turns out to be less standard than it first appears. With valves for power generation it pays to include phase changes in the medium, because those sharply increase the load on the seal. We think along from the basic specification through to the tag plate, and supply documentation that a buyer or inspector accepts without discussion.
What should I watch technically on valves for power generation?
What should I watch technically on valves for power generation?
Which applications call for valves for power generation?
In power generation these valves sit on the critical paths around boiler and turbine, where downtime costs money immediately. They are used in power stations, combined cycle plants, waste to energy installations and industrial cogeneration. In process industry steam is used for heating, stripping and sterilisation, and each of those duties sets its own requirements. Boiler houses, combined heat and power plants and district heating together form the largest application area for these valves. That makes valves for power generation a subject where discussion up front pays for itself in operation. We always explain why we arrive at a particular recommendation on valves for power generation, so you can follow the reasoning yourself. Our customers use valves for power generation in positions where a failure has immediate consequences for production. Dutch Valve Vision supplies special valves for special applications from its base in Monster, the Netherlands, with QUADAX and PRUSS as the core brands in the programme.
What determines the price and lead time of valves for power generation?
We come back with a proposal that explains why we recommend a particular execution, including the alternatives we considered. Please also state the connection standard, the required leakage class and any project requirements such as NACE, PED or ATEX. We quote a realistic lead time rather than an optimistic one, because a missed delivery date costs more than an extra week in the planning. For shutdowns and turnarounds we look at accelerated routes, and in those cases we are honest up front about what is and is not achievable. Our experience with valves for power generation comes from projects in chemicals, power generation, technical gases and offshore. The answer on valves for power generation depends strongly on operating conditions, which is why we always ask for those first. Dutch Valve Vision stays available after delivery of valves for power generation for technical questions and for parts. Send us your DN, pressure class, medium and temperature at sales@dutchvalvevision.com, or call +31 (0)70-2210560 to speak to a specialist.
What about maintenance and spare parts on valves for power generation?
Documentation such as material certificates, test reports and declarations is supplied as standard, matched to what the project requires. We keep spare parts and overhaul kits mapped per project, so that a breakdown does not start with a search from scratch. On repeat orders we record the configuration, so a follow up delivery is identical to the first and installation holds no surprises. Insulation around a steam valve should leave the actuator clear, because overheating of the actuator is a common cause of failure. On valves for power generation we prefer a well founded answer to a fast one that turns out to be wrong later. We see this come back regularly in enquiries about valves for power generation, and the answer is rarely a single sentence. On valves for power generation we make sure the chosen execution demonstrably meets the stated standards rather than merely looking plausible on paper. Our market is project driven and international, and we deliver worldwide to installers, EPC contractors and end users.
How do I request a quotation for valves for power generation?
If you have an existing tag plate or serial number, send it along, because that lets us work directly from the original configuration. A P&ID, a datasheet or even a photograph of the existing installation often helps us faster than a long description. For an accurate quotation we need the nominal diameter, the pressure class, the medium, the operating temperature and the required actuation. Lead times depend on the execution, because a standard size from a running series behaves very differently from a valve in an exotic alloy with NACE certification. If you are unsure about this on valves for power generation, we are glad to put the question alongside the actual process data. In most projects valves for power generation turns out to be less standard than it first appears. We think along on the spare parts strategy for valves for power generation, so critical positions stay covered. Requests can be submitted by phone on +31 (0)70-2210560, by e-mail at sales@dutchvalvevision.com or through the contact form on our website.