Abstract
The paper sector is affected by many challenges, especially related to increased competition for raw materials and energy. In this thesis several opportunities are identified that enable the sector to reduce its’ dependency on energy and resources, lower its energy costs and reduce its carbon footprint. Based on detailed energy
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benchmarks of different processes within the Dutch paper industry, significant energy efficiency improvement opportunities (15%) were identified by implementing existing best practices. The largest improvement potential is in the drying section. By means of a thermodynamic optimisation, it was shown that an increase in dew point decreases energy use of water evaporation and increases the heat recovery potential of exhaust air; applying additives in higher consistencies further decreases water evaporation. Combining best practices and retrofits in the drying section, an energy efficiency improvement potential of 22% was found to be possible for Dutch paper machines. Our results further show that increased recycling and enhanced recyclability of paper grades offer good improvement potentials for the sector. Current paper recycling rates in The Netherlands (75%) have led to 3 Mt avoided CO2 emissions per year, compared to a situation without recycling, equalling approximately 9% of the total Dutch industrial CO2 emissions in 2007. Only a few European countries have reached their limit in paper recycling, whereas in most countries there is still potential for growth. A 10% increase in recycling could bring 10% savings in primary energy and CO2 emissions over the total life cycle of paper. CHP could in many countries be an interesting improvement opportunity as the technology fits well to the paper industry and it can lead to 2-3 times lower primary energy demands. Biomass energy conversion technologies should be implemented when possible and feasible, as they are effective in reducing CO2 emissions, especially in cases that are currently based on carbon-intensive fuels. For the Dutch paper industry, due to the lack of domestically available biomass, most of the biomass based alternatives do not seem promising alternatives; for them improving energy efficiency and maintaining the high implementation level of CHP are the most feasible routes for improving its energetic performance. The variety of research methods applied, take into account the sector’s complexity in terms of variability of feedstock and product ranges and have contributed to a more detailed and nuanced analysis of energy efficiency improvement and CO2 reduction potentials compared to earlier studies. The work in this thesis stresses the importance of using non-aggregated data, especially when benchmarks are to be used in industrial target setting. We show that using a single indicator is often not sufficient to determine the sustainability or improvement potential of paper production chains. Also in policy making, trade-offs between various sustainability indicators are often not well reflected. While policy makers are nowadays focused on renewable energy targets, the deteriorating economic position of CHP is leading to several closures of CHP facilities, resulting in a consequent increases in primary energy demand. The methodologies applied in this thesis enable to account for these types of effects.
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