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Boiler water and steam control solutions

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Cavitation in boiler water feed pump axles. This occurs due to low pressure in condensate deareators caused by poor control by the pressure regulating valve.
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Condensate deareator pressure regulation valve
This valve maintains a constant pressure on water accumulated inside the deareator; assuring a sufficient net positive suction head (NPSHD) to eliminate cavitation in water feed pumps.
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Pneumatic recirculation valves fail due to cavitation and flashing that result from high pressure drops across them. These problems affect internal trims, thereby causing leaks that affect the normal pumping pressure.
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_Recirculation valve protection
"Anti-flash" valves protect recirculation valves by increasing pressure downstream of the recirculation valve, eliminating cavitation and flashing caused by high pressure drops.
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Multistage boiler feed pumps suffer severe damage due to hydraulic imbalances caused by sharp variations in pressure. These variations are caused when the dome level control valve closes faster than the pneumatic recirculation valve opens.
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_Protection of multistage pumps with recirculation
Three-way, direct action, recirculation valves open instantaneously with flow changes caused by opening or closing of the dome level control valve. This action protects pumps from wear by eliminating sharp pressure variations.
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Many water-tube boilers have problems controlling water level at the dome when the control valve deteriorates as a result of an incorrect selection.
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Boiler dome level control
A correct boiler dome level control valve requires a careful analysis of the pump's operational curve in order to determine the correct trim characterization and the Cv values at full and minimum load.
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 It is usual to find safety valves on the dome, the superheater, turbine outlets and other points in the steam process that have leaks and operate erratically.
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Safety valves
Typical safety valve problems in power plants are a result of an incorrect selection and deficient operation and maintenance programs. We offer 25 years of experience solving these problems.
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Original superheaters installed in many water-tube boilers suffer from premature deterioration due to high temperatures as a result of incorrect desuperheating. This problem consists in erratic and insufficient responses to urgent requirements for steam conditioning.
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Superheater protection with multiple nozzle desuperheaters
As opposed to typical desuperheaters that depend on control valves to regulate the pressure at the nozzles, multiple nozzle desuperheaters offer immediate and accurate response to demand variations.
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Superheaters require a minimum steam flow in order to maintain temperature below design allowed limits. Turbine exhausts significantly reduce steam flow at the superheaters, provoking their premature deterioration. Furthermore, these exhausts cause sudden pressure increases that set off the safety valves, damaging their seal.
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Venting valves for superheater protection
A pneumatic venting valve that opens as a response to sudden pressure increases by the turbine exhausts, prevent the safety valves from discharging, by limiting the pressure. Flow discharged by this venting valve is equal or greater than the required flow to protect the superheater.
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Most plants that use steam from turbine exhausts for heating processes (sugar mills and palm oil extraction plants) require turbine bypasses. This application is severe due to the high pressure drops that erode the seats and discs of most general service control valves.
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Turbine bypass control with severe duty valves
We select valves that are specifically designed for this application, and thereby, eliminate the leakages caused by internal trim erosion.
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Once the pressure has been reduced with the turbine bypass control valve (see product 8) or by the passage through the turbine, the steam must be conditioned for use in plant processes. Usually these systems are non-existent or do not achieve a correct desuperheating, and therefore affect the heating processes.
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Heating process annular desuperheater
Annular desuperheaters are very efficient for low flows and temperatures of steam after turbine exhausts or bypasses, because the design assures an efficient mixture between steam and water.
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Steam leakages through eroded seats and discs in control, stop, drain and other valves represent significant losses of thermal efficiency in water tube boilers. Most globe type stop valves in these installations have leakages.
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Zero-leakage stop valves for severe duty applications
Zero-leakage sealing technology eliminates these leakages. The energy savings allow for a quick return on the investment for the replacement of these valves.
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Todos los derechos reservados 2020 - Valvexport, Inc. Tecnología para Control de Fluidos - Chicago, USA
Todos los derechos reservados 2020 - Valvexport, Inc. Tecnología para Control de Fluidos - Chicago, USA