Valve design
The DSCV-SA valve : a modern solution to steam conditioning
Mark Wheat , Celeros Flow Technology , outlines how technical innovation and leading-edge valve design has improved the conditioning of superheated steam used in power generation and other essential industries .
By Mark Wheat , Celeros Flow Technology
The pressures and temperatures involved in generating energy from steam continue to grow , making new demands of critical flow control equipment such as valves .
Many industrial activities rely on steam for their processes , including power generation plants , refineries , and paper mills . The means to generate energy using steam have been understood for centuries . The basic principles , using a boiler , steam turbine and generator , remain largely unchanged . However , the pressures and temperatures involved have increased considerably . This article explains how Celeros FT brand Copes- Vulcan developed the critical steam conditioning valve technology that meets the rigours of modern steam energy generation .
A brief history of steam
Early coal-fired steam generators provided lowpressure saturated or slightly superheated steam for steam engines driving DC dynamos . The first steam turbine generator , built in 1884 , had a thermal efficiency of just 1.6 %. Six years later , General Electric delivered the world ’ s first 5-MW steam turbine . The 1910s saw the introduction of turbines with steam extractions for feedwater heating and steam generators equipped with air preheaters — all of which boosted net efficiency to about 15 %. Main steam temperatures consistently increased through the 1940s ( the decade that also saw the first attempts to clean flue gas using dust removal ). The 1950s and 1960s were characterized by more technical achievements to improve efficiency — including construction of the first oncethrough steam generator with a supercritical main steam pressure . Unit ratings of 1,300 MW were reached by the 1970s . In 1972 , the world ’ s first integrated coal gasification combined cycle power plant — a 183-MW power plant for the German generator STEAG — began operations . Vast improvements in component performance have continued from the mid-20th century to the present day .
Operational challenges
A steam power plant essentially uses a boiler to generate steam at high pressure and high temperature . A steam turbine converts the heat energy of steam into mechanical energy , and a generator then converts the mechanical energy into electric power . Water boils at 100 ° C under normal atmospheric pressure [ 0.101 MPa ]. As pressure increases , the boiling temperature of water also increases . When the pressure is increased to 22.12 MPa , and at a temperature of 374 ° C , water is directly converted into steam . This is called the critical point . Pressure above this critical point , with a temperature equal to or more than 593 ° C , is called ultra-supercritical pressure . Handling superheated steam at these pressures and temperatures places enormous strain on flow control equipment . Inadequately specified
18 Valve World February 2024 www . valve-world . net