Steam pressure-relief systems
The purpose of water vapour expansion systems is to:
- Relief of highly pressurised water, steam and water-steam mixtures
- Separation of water and steam in a drain relief valve
- Discharge of water, without turbulence and, if required, with recooling in a collection tank
- Discharge of steam into the atmosphere via a vapour line and a blow-off silencer
When the pressure of highly pressurised hot water is reduced, a considerable amount of heat of vaporisation is released. This creates a water-steam mixture, which is separated into its individual phases. This phase separation takes place in the drain valve, through which the remaining condensate is discharged into a collection tank and the resulting steam is discharged to the outside via a vapour line and a downstream blow-off silencer.
Throttle systems are used to reduce the noise level of the medium to the pressure level in the container. The medium flows through several throttle stages in a radial direction. The number of stages depends on the level of the inlet pressure and the required noise reduction.
The dimensions of the expansion vessels are determined based on the design (tangential or gravity expansion vessel), the mass flows to be introduced and the thermodynamic state variables. Phase separation in the vessel is supported by internal components such as baffle plates, flow chicanes and demister packs.
A complete condensate system consists of the main components expansion and condensate vessels, blow-off silencers and – in addition to the vapour pipe – a large number of pipes, which are coordinated in terms of dimensions, operating behaviour and acoustic effect.
The advantage of our offer to supply complete water-steam expansion systems lies in the interface-free plant optimisation in accordance with the requirements of process engineering, acoustics, the regulations governing pressure vessel construction and the statics of the overall system.
The typical scope of services provided by basic engineering includes:
- Process engineering design with determination of all main dimensions, cross-sections and volumes
- Creation of an acoustic concept with design of sound-absorbing components in the discharge relief valve and design of the blow-off silencer
- Specification of all equipment parts and the structural design of the individual components
- Design of sound and heat insulation
- Support, guide and expansion concept for all components with stability verification
We use modern computer-aided 3D design tools for the technical design of the plant. Parallel to three-dimensional virtualisation in the CAD system, the structure is automatically networked, after which FEM analysis is used to calculate stresses and strains based on specified boundary conditions such as pipe connection and wind forces, internal pressures and temperature fields.
The complete system is constructed in accordance with coordinated and approved preliminary documentation. Delivery to the construction site is carried out after cost-optimised determination of transport and assembly sizes.
The documentation typically includes
- Main dimensions
- Platform levels
- Load introductions, forces and expansion data in the x, y, z directions
- Information on manufacturing and acceptance regulations
- Welding specifications
- Quality and manufacturing documentation
