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In this work an assessment of the compressed air system in the facilities of Vattenfall Heat Uppsala has been conducted. The facilities constitutes, among others, a combined heat and power plant, and two waste incineration plants. The compressed air is supplied primarily by seven rotary screw compressors and yearly electric energy consumption in these has been determined. Furthermore, the usage of compressed air has been mapped in order to find processes with energy savings potential. Several suggestions how to reduce the usage of compressed air have been presented, resulting in decreased need of electric energy and reduced CO2-emissions. The results show that total need of electric energy in the compressors, during a standard production year, amounts to 5.83 GWh. The proposed process changes, if all of them are implemented, will save around 1 GWh/year. The reduced energy usage results in a financial gain of roughly 600 kSEK/year and about 400 tonnes of CO2-emissions can be avoided.

No description available.

För att skapa konkurrenskraft krävs alltid optimering, av flera olika processer, mot mer energi- och kostnads-effektivitet. Anläggningen som används i detta projekt, ett kraftvärmeverk som byggdes så sent som 2015, har dragits med vad som verkat vara en icke optimal drift av tryckluftssystemet med tre identiska, frekvensomformarstyrda kompressorer. Målsättningen med detta projekt var att ta fram förslag på en mer optimal styrning av anläggningens tre kompressorer samt att implementera den för att genomföra en analys om resultatet. En nulägesanalys visade att det fanns utrymme för förbättring av styrningen samt att en del regulatorparametrar skulle behöva optimeras. Två regleringsförslag togs fram, som till stor del vara ganska lika men med den stora skillnaden att förslag ett använda sig av kompressorernas tryckregulatorer och det andra förslaget styrde kompressorernas varvtal direkt från PLC:n. I slutet på detta projektet, när de nya regleringsförslagen skulle implementeras, var anläggningen i ett tre veckor långt driftstopp för underhåll. Detta påverkade optimeringen genom att förbrukningen av tryckluft var låg. Detta skulle lett till att en parameteroptimering inte skulle blivit helt optimal. Eftersom kompressortillverkaren inte valde att samarbeta fanns dessutom ingen möjlighet att utföra en parameteroptimering på alla regulatorer. Trots dessa omständigheter så har en viss optimering troligen skett med det nya regleringsförslaget. / In order to create competitiveness, optimization towards more energy and cost efficiency is always required, of several different processes. The plant used in this project, a cogeneration plant that was built as late as 2015, has been drawn with what appeared to be a non-optimal operation of the compressed air system with three identical air compressors whom are controlled by frequency converters. The objective of this project was to produce proposals for a more optimal control of the plant's three air compressors and to implement it to carry out an analysis of the result. An analysis of the origin operation showed that there was room for improvement of the control and that some controller parameters would need to be optimized. Two regulatory proposals were developed, which to a large extent are quite similar but with the great difference that the first proposal make use of the compressors' pressure controllers and the other proposal controlled the speed of the compressors directly from the PLC. At the end of this project, when the new regulatory proposals were to be implemented, the facility was in a three-week downtime for maintenance. This affected the optimization because the consumption of compressed air was low. This would mean that a parameter optimization would not be completely optimal. Moreover, since the compressor manufacturer did not choose to cooperate, there was no possibility of performing a parameter optimization on all controllers. Despite these circumstances, some optimization has probably occurred with the new regulatory proposal.