10/07/24
Have you seen the buzz around our DSCV-SA steam conditioning valve? Leading trade publications Valve World, Industrial Plant & Equipment and Process & Control have recently featured articles about the benefits that the DSCV-SA brings to modern steam energy generation.
Mark Wheat is Copes-Vulcan Global Technical Sales Manager for Celeros Flow Technology and author of the technical articles. He says: “Valves for superheated steam control need to deliver operational reliability and withstand extreme operating conditions, particularly during plant start-up, shutdown, and turbine trips. The DSCV-SA addresses the issues encountered by older, base load designed bypass valves and delivers big benefits when employed on modern high frequency, rapid ramp rate plants.”
Unlike conventional turbine by-pass valves, the DSCV-SA is designed to use high-pressure balance rather than low-pressure balance. This eliminates risk of wear, damage or breakage relating to piston rings and balancing systems, reducing downtime and maintenance costs. It also avoids stem load fluctuations due to worn seals and surfaces, which can cause low-pressure valves to oscillate violently or not open on command.
The DSCV-SA features steam atomization technology that has significant benefits over mechanically spraying the cooling water via nozzles. Mark Wheat explains: “Mechanical spray nozzles rely on the surrounding steam velocity to provide adequate mixing. When the steam load reduces, so too does the steam velocity and the ability of the mechanical spray nozzles. This results in poor downstream steam temperature control and water ‘drop-out’, which can cause high thermal shocks and lead to steam header fracture.”
“With steam atomization, the cooling water is pre-heated; significantly accelerating the evaporation and desuperheating process and producing extremely small water droplet sizes that promote rapid heat transfer. Because this method of water introduction does not rely on surrounding steam velocity or turbulence for effective mixing, it gives very high turndowns - generally in excess of 100:1.”
Modern steam turbine bypass systems must also be able to react and modulate very quickly under emergency conditions such as a turbine trip. Stroking speeds of less than one second may be required in emergency conditions. The DSCV-SA can be supplied with either pneumatic or hydraulic actuation to meet this critical requirement.
Low maintenance is another design feature of the DSCV-SA. Its ‘Quick-Change’ style trim has no welded-in components or large internal threaded parts. The whole trim assembly is held in compression and simply removing the compression ring or bonnet allows the whole trim to slide out. This makes in-situ maintenance, if required, quick and simple with no need for specialised tooling or training.
Robustly designed, the DSCV-SA is available in an almost infinite range of sizes, materials, and pressure ratings because each valve is tailored to suit individual customer requirements.
For more details, visit our product page.