AFRY Steam Balance
AFRY Steam Balance describes AFRY's unique set of high-tech solutions covering everything that is needed to optimise combined heat and power (CHP) plant steam balancing.
Almost all industrial power plants encounter problems when process disturbances occur. Process interruptions, such as paper machine web breaks or turbine and boiler trips, do not only cause unnecessary down time for manufacturing processes but also lead to inefficient steam balancing between process and CHP plant that result in notable economical losses due to increased operating costs.
AFRY has developed a method to integrate power plant control systems so that operations are optimised both economically and technically. During the design work, all imaginable process disturbances are tested with dynamic simulation utilising AFRY Modysim™ software.
Dynamic simulation in power-plant engineering
AFRY's control experts assist in all power-plant engineering stages, from the first feasibility studies to commissioning, ensuring that the power-plant will be started smoothly, operations remain stable and process steam availability is high.
Power plant design methods that are in use today too often presuppose that the steam consumption of an industrial host is completely steady throughout one day´s or one hour´s operation. The reality of many industrial processes, such as pulp and paper milling, couldn't be more different: steam load typically shifts all the time, up and down, when breaks on big paper machines and cyclical operation of batch digesters take place. Turbine and boiler trips are an added factor among the operational challenges.
It is typical that steam-net controls are developed only during commissioning, through trial and error. It often takes months to get the power plant running reliably and efficiently after initial start up.
AFRY's CHP plant engineering tests these disturbances in the early stages of power-plant concept development using AFRY Modysim™, our own steam-network simulator. Simulation can be ensure that
- process component dimensioning is correct
- possible steam accumulator is correctly dimensioned
- steam-pressure control configuration is correct, also in the turbine and boiler controls
- highest possible steam availability can be achieved
- CHP plant can be commissioned quickly without control related teething problems
Steam-net optimisation projects
AFRY has the know-how to stabilise any fluctuating steam-network. The solution requires controller reconfiguration in the plant DCS and in some cases an installation of a steam accumulator. AFRY has carried out more than 70 steam-net optimisation projects all over the world offering the clients significant value.
Surprisingly many industrial power plants have serious problems with unstable steam pressures. They are not only an operational challenge: economic losses due to inefficient steam balancing are typically between EUR 0.2 million and EUR 2.0 million annually at almost all paper mills.
AFRY has a unique track record in optimising power plant steam balancing. Over the years the work process has become straightforward, and there are already over 70 successful references all around the world.
A typical project starts with a control audit including feasibility estimation of the implementation.
In the second phase the feasibility is calculated accurately with the help of a steam-network dynamic simulation with the Modysim™ programme.
In the implementation phase a specification for the control modifications is prepared. AFRY's specialists supervise the reconfiguration of the turbine and automation systems and after that finetune all the controllers. Steam pressure stability in the low-pressure header typically achieved in our projects is ± 0.05 bar during stable conditions and ±0.1 bar during disturbance situations.
A steam-net optimisation project often has a short pay-back time, typically less than a year.
AFRY Steam Balance EPC Package
A turn-key delivery of a steam accumulator and advanced controls
AFRY has carried out over 70 steam network optimisation projects having gained solid experience on both steam-network controls and steam accumulator installations.
A steam accumulator is a powerful tool in steam-network stabilisation and economic optimisation of the operation. However, as a steam accumulator itself is only a pressure vessel, it needs to be equipped with an advanced control system in order to get the most of the equipment.
AFRY is the only company in the world able to deliver a total solution for steam balancing as turn-key supply. The delivery can include steam accumulator vessel, an advanced steam-net control system and functional guarantees.