In English

The Potential for Frequency Control in Paper Mills - With Particular Reference to Iggesund Mill

Pierre Hult
Göteborg : Chalmers tekniska högskola, 2015. 62 s.
[Examensarbete på avancerad nivå]

As more intermittent energy resources are entering the energy system the need for frequency regulation increases rapidly. At present, most of the frequency regulation is taken care of by hydropower. It is though becoming more difficult for the hydropower to take care of frequency control alone, especially at night when much of the hydropower is out. The costs of the frequency control can then by relatively high. The possibility for CHP plants and paper mills to make financial gain through participation is then of interest to investigate. In this thesis the possibility for paper mills and especially Iggesund Paper Mill to participate in the Primary frequency regulation has been looked at, with respect to process and control changes. Paper mills usually consist of a recovery boiler and in some cases additional boilers with relatively slow response and one or more steam turbines to generate power. The problem is to meet the fast power response to the grid required for participation while still satisfying the steam demand for the steam consuming processes in the paper making. A simplified model of Iggesund mill has been modelled using the software Dymola. A graphical interface that easily build and simulate large complex systems with many fixed equations. Different control methods and their effect on the system as a whole have been analysed. If the control system is fairly redesigned and the oil fuel inputs are maximized in one or more of the boilers during frequency deviations, Iggesund mill can participate to some extent. Maximizing the oil inputs is however not desirable in the long term as the aim is to be independent on fossil fuel. The damage and stress it would do to the boilers is questionable. Throttling of steam past the turbine and redistributing for ramp up seems to be the easiest and cheapest way to control the plant in participation.

Nyckelord: Frequency control, Pulp and Paper mills, Steam network, Dymola, Time delay, Modeling

Publikationen registrerades 2015-11-04. Den ändrades senast 2016-01-14

CPL ID: 225274

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