Återvinning av industriell restvärme som värdeskapande process : En fallstudie på SSAB EMEA i Borlänge

Detta är en Master-uppsats från KTH/Tillämpad termodynamik och kylteknik

Sammanfattning: The industrial sector accounts for a large share of greenhouse gas emissions. To reduce its negative impact on the environment is crucial in the quest for a sustainable future. In discussions of the industrial sector's impact on the environment guidelines have been highlighted as a tool to assist the industries in their efforts to change the relationship between the consumption of energy and production. This by improving energy efficiency and a shift to the best available technology. During the past 30 years the steel industry has reduced its energy consumption per ton of steel produced by 50 percent. However, due to this dramatic improvement in energy efficiency, it is estimated there is now only room for a marginal further improvement on the basis of existing technology. More innovative solutions are therefore required to further improve energy efficiency and achieve a more sustainable use of resources. In a description of the program Efficiency of Energy Use in Industry – Research and Development undertaken by the Swedish Energy Agency the interaction between industry and society is accentuated as an important factor in energy efficiency efforts. Today, there are already several examples of where the industry and the community work together to achieve a better utilization of resources. The steel industry SSAB EMEA has a manufacturing plant in Borlänge, Sweden, where they have been recycling waste heat from the industrial processes for a long period of time. In 1991 SSAB initiated collaboration with the local energy company regarding recovery of waste heat within the industrial enterprise. Since then, SSAB has contributed to the heating of the residences that are connected to the local district heating network. The present study aims to examine the values that the utilization of waste heat add to the industrial company and the community, and to explore how the use of industrial waste heat can be developed ahead. The examination consists of a case study and is mainly based on qualitative interviews with people from SSAB, the local energy company Borlänge Energi, Borlänge Municipality and the Swedish Energy Agency. Some quantitative data, such as measurements of heat deliveries, have also been used for the analysis. In addition a literature review with a focus on district heating in Sweden, industrial waste heat and instruments in energy and climate policy has been conducted. Through varied system levels the waste heat collaboration in Borlänge has been analyzed from a business, social and sustainable perspective. The result of the case study proves that the waste heat collaboration has added value in all perspectives. Business values that have been identified are reduced purchases of oil, compensation for delivered waste heat, exchange from vapour to in-house district heating within the steel factory site, reduced emissions of carbon dioxide, media attention and an improved brand and that the waste heat collaboration possibly made SSAB a more desirable employer. The use of industrial waste heat for district heating in Borlänge has also generated a range of social benefits, which consist of low operating costs for heat, low price of district heating, good energy mix and better air quality and less acidity. From a sustainability perspective, the waste heat utilization resulted in reduced emissions of carbon dioxide and other air pollutants and has been contributive to a sustainable use of raw materials and energy resources. The results also demonstrate that there are both opportunities and threats to a continued use of industrial waste heat. The opportunities identified are regional district heating networks, which can improve the conditions for effective use of waste heat, district cooling, which may increase the need for waste heat in the summer and in-house electricity production, which can accommodate some of the steel company's electricity need. A few threats to a continued use of waste heat have also been identified, which the first consists of co-generation and waste incineration, which can adversely affect energy companies incentives to enter into and renew agreements on waste heat deliveries since the companies do not want to be afflicted with reduced revenues from sales of electricity and electricity certificates or from the reception of waste. Furthermore has changes in energy policy been identified as a threat since for example a new tax on waste heat could worsen the conditions for both continuing and new waste heat collaborations.

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