Operation & Maintenance of Power Plants
Pressure safety for the energy and power generation
Continuity in power production and energy distribution is critical for the sustained economical growth of any industrial region. Roger Bours reports.
T
he consideration of protecting critical assets such as power generators, steam circuits, transformers, switchgear, heat exchangers, etc, against unacceptably high internal pressures or explosions
is necessary and well introduced into today’s risk reduction methodology. Due to the high-investment costs and long delivery times of the related process equipment, combined with the induced risks related to the presence of concentrated energies, the incidental occurrence of unacceptably high overpressures must be considered. Such overpressure situation would put the continuity of energy supply at risk and would create unsafe situations for the employees working in the energy industries.
Controlling the energy Steam-driven energy cycles are inherently linked with pressure risks in the (high-pressure) steam circuit equipment such as steam condensers, heat exchangers and boilers. Due to the high levels of stored/produced energy
damages resulting from such overpressure incidents may be devastating, with injuries or fatality risks being very high and loss of production capability for long repair or replacement periods being eminent.
Biofuels Where biofuels are handled (coal, biomass, peat) the storage, handling and transportation of such combustible materials must be protected against the effects of dust explosions through the use of industry accepted protection measures. Suitable protection techniques with proven
reliability and performances are available; they include (explosion) pressure relief through the use of rupture discs or explosion venting devices, explosion suppression and isolation measures for coal or biomass milling (when used in co-firing), storage facilities (silos) and bulk handling (transportation and drying).
First line of defence As a first line of defence pressure control systems are typically used. Tese monitor the pressure developments in the process equipment and will interact timely with the process control system to limit the pressure to acceptable levels. As in most cases pressure control systems may not assure the required level of reliability in all service
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conditions, the use of pressure relief systems is often required. To attain the required safety against pressure risks the industry has been using pressure relief devices. Such pressure relief devices are categorised in reclosing and non-reclosing types, both offering unique characteristics making the selection process for the design engineer possible.
Relief device options Te industry has been working traditionally with (reclosing) relief valves or (non-reclosing) rupture (or bursting) disc devices to achieve pressure relief action. Both types are accepted for use as independent relief devices, protecting the installations against unallowable pressures.
Fig. 1. Due to the high-investment costs and long delivery times of the related process equipment the incidental occurrence of unacceptably high overpressures must be considered.
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