Deep decarbonization of the pulp and paper industry: Heat integration and techno-economic analysis combined with tailored heat pumps

This study evaluates high-temperature heat pumps for the pulp and paper industry, designed to achieve deep decarbonization by covering ∼19.6 MW out of 24.3 MW of the hot-utility demand (∼80%), including steam at 150 °C, using waste heat from the same site. While this 80% coverage is based on a Swiss case study, it reflects typical steam demand structures in the pulp and paper industry globally. Three configurations were developed to address challenges of high-temperature operation and working-fluid optimization, using modifications such as intercooling and internal heat exchangers. These solutions are broadly applicable beyond the paper sector, making high-temperature heat pumps key tools for industrial decarbonization. Techno-economic analysis showed the Intercooler-Water system achieved the highest efficiency (COP 2.73), while the internal heat exchanger system offered simplicity and lower costs ($24.3M vs. $90.5M). Economic analysis under four scenarios revealed the internal heat exchanger system performed best at low electricity-to-gas price ratios (0.5–1, Scenario 1) with a mean payback of 1.82 years and LCOE of -9.93 cents/kWh. At higher ratios (2–3, Scenario 4), the Intercooler-Ethanol system was the most adaptable, with a payback of 5.15 years and LCOE of -6.77 cents/kWh. Intercooler-Water, while efficient, struggled with high investment costs and paybacks exceeding 7 years. Sensitivity analysis identified energy prices as the dominant factors, with investment costs critical for the Intercooler-Water system. These findings provide a roadmap for optimizing heat pump integration and aligning designs with market conditions, ensuring feasibility in decarbonizing not only the paper industry but also other sectors. • High-temperature heat pumps cover 80 % of steam demand using site waste heat • Three configurations developed for dry/wet fluids at 150 °C industrial demand • Isopentane-based system performs best under current conditions with low investment • Ethanol-based system is most robust across future price and energy scenarios • Sensitivity analysis reveals energy price and investment as key feasibility limits