Perspectives for Power Generation fromIndustrial Waste Heat Recovery

Sammanfattning: This thesis work was carried out at Siemens in Germany in the department of Steam Turbines, and aims to raise awareness of the potential for broader deployment of waste heat recovery (WHR) from industrial processes for power generation. Technologies available to recover heat are presented and sorted out according to the features of the heat source. In particular, ORC and water-based cycles are compared in terms of efficiency and other advantages and their sensitivity to variable parameters. As far as the efficiency is concerned, the type of technology does seem to have less impact than the size of the installation. Organic fluid cycles have properties that could encourage their selection, like smaller size of equipment, better efficiency during offdesign operations or no make-up water supply. This study also presents different segments where WHR systems are possible. In the short term, cement, electric arc furnace and glass industries are the sectors that offer the best opportunities for WHR integrated with power generation. In a long-term view, future large systems for power generation tend to disappear with the expected optimization of the industrial processes. Instead, there would be opportunities to develop waste heat recovery systems for non-continuous flows and low temperature streams coming for instance from cooling processes. Considering the progress in technologies development in the past years, understanding the economic environment is the real challenge to develop a WHR market. Technologies are indeed available but often too expensive or not sufficiently well-known by the industrial players. In that context, subsidies from national governments or organizations can be a crucial option to push the development forward. Nevertheless, the comparative evaluation shows that the rising costs of energy in the future will inevitably provide more opportunities for market-ready WHR systems.