Optimizing energy use in the pulp and paper industry: Pinch, techno-economic, and sensitivity analyses on an innovative heat recovery system

This paper explores decarbonization strategies and energy efficiency improvements in the pulp and paper industry, which accounts for nearly 5 % of global industrial energy consumption and 2 % of direct CO₂ emissions. Using Pinch Analysis, the research identifies potential energy savings of 39 % of total heat demand for primarily non-integrated and minimally integrated pulp and paper mills. The study proposes implementing an Intermediate Water Loop system to facilitate heat exchange, offering a flexible and efficient approach to overcoming spatial and operational constraints in heat recovery. The economic and environmental benefits of these solutions are evident, with significant reductions in energy costs and CO₂ emissions. For example, one of the two large paper mills in Switzerland shows a direct heat recovery potential of 26.8 MW (49.8 % of the total heating demand), resulting in a levelized cost of energy savings of 1.14 cents/kWh (while gas price is approximately 15 cents/kWh), a payback period of 1.08 years, and a reduction of 46.36 kt/year in CO₂ emissions. A comprehensive techno-economic and sensitivity analysis identifies key parameters influencing economic performance, such as gas prices, discount rates, and the cost of equipment, highlighting the importance of optimizing these factors. The methodologies and strategies discussed in this study are replicable on a global scale, showcasing the potential for significant economic and environmental gains in the sector.