Technical, economic, and environmental analysis of integrating a high-temperature heat pump into a pulp and paper industry in Italy
This study presents a comprehensive technical, economic, and environmental analysis of integrating a high-temperature heat pump (HTHP) coupled with a mechanical vapor recompression (MVR) system into the steam generation process of a pulp and paper industry in Italy. The HTHP is designed to extract 600 kW of thermal energy as waste heat at 90 °C, producing saturated steam at 115 °C, which is further compressed by the MVR to 162 °C and 6.5 bar(a), meeting the plant’s steam header requirements. The system is expected to operate for 7,000 hours annually, delivering 5.8 GWh of heat and consuming 2.0 GWh of electricity, with a system COP of 2.85 and second-law efficiency of 49%. The techno-economic analysis reveals a total capital expenditure (CAPEX) of 0.8 M€ and annual operational expenditures (OPEX) savings of 94.0 k€/y compared to a conventional gas boiler, resulting in a simple payback period of 8.4 years, a levelized cost of heat of 0.09 €/kWh, and a return on investment of 13%. Environmentally, the proposed system achieves a 43% reduction in CO2 emissions, saving 725.0 tons of CO2 annually, equivalent to 69.0 k€/y in emission costs. Moreover, a parametric study was conducted to highlight the sensitivity of performance to various source and sink temperatures, flow rates, working hours, and emission taxes. The results demonstrate the viability of HTHP+MVR systems as a sustainable alternative for industrial heat upgrading, contributing to the decarbonization and energy efficiency goals.