PAPER making! g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® Volume 11, Number 1, 2025
dominants the energy sources with a share of 68.4 – 47.2%. Total carbon emissions ranged from 129 to 184Mt CO 2 , among which, 15.2 – 22.8% was attributed to biogenic emissions. The average annual growth rates of total energy use and carbon emissions were 2.5% and 2.1% over the studied period. However, the carbon intensity shows a downward trend except in the year of 2013 and 2018. The average annual decline rates of energy intensity and carbon intensity were 2.4% and 2.7 – 2.9%, respectively. The LMDI decomposition results demonstrated that the growth of paper production was the main factor driving carbon emissions, while energy intensity and the emission factor of electricity were the main counteracting factors. In addition, the energy structure changed from increasing to decreasing carbon emissions. Therefore, reducing energy intensity by energy efficiency improvement, changing the energy structure from fossil energy to biomass fuel, and applying more green electricity should be encouraged and implemented continuously to achieve the carbon peak and carbon neutrality goals for CPPI. “ Energy consumption in refiner mechanical pulping ”, Richard Kerekes and Christer Sandberg, Nordic Pulp & Paper Research Journal , online Feb. 2025. The efficiency of mechanical pulping has long been of interest due to the large energy consumed by the process. Previous estimates of theoretical efficiency have accounted for less than 20 % of the energy employed. In this study, we make new estimates based on fracture mechanics and abrasion as the mechanisms of new surface creation. We postulate that fracture mechanics comminutes wood into fibres and creates pores in fibre walls. This consumes around 100 kWh/t. Abrasion peels surface material from fibres in the form of morphologically different fines particles. Based on abrasion theory, we estimate this specific energy to be around 1,330 kWh/t. Together, fracture mechanics and abrasion, account for about 70 % of the specific energy (2,000 kWh/t) to produce TMP for printing paper grades. We postulate that the remaining energy is consumed as hysteresis losses from viscoelastic strains not linked to creation of new surface. The largest single source of energy consumption, abrasion, alone accounts for about 66 % of the energy of the process. Finally, we discuss how energy may be reduced by refining intensity and other means. “ Comprehensive Analysis and Optimization of Waste Heat Recovery and Utilization in Paper Drying Process ”, Comprehensive Analysis and Optimization of Waste Heat Recovery and Utilization in Paper Drying Process , Mao Tang, Mou Zhang, Xianghong Zhou, Ke Cai, Shicheng Hu, Lei Wu & Wenxuan Cao, available at SSRN: https://ssrn.com/abstract=5133240 or http://dx.doi.org/10.2139/ssrn.5133240. This study presents a comprehensive analysis and optimization of waste heat recovery and utilization in the paper drying process, a critical energy-intensive industry. Amidst rising energy prices and the looming energy crisis, the paper industry, which consumes approximately 7% of global industrial energy, faces significant challenges. The drying process, accounting for 70% of total energy expenditure in paper production, is a prime target for energy efficiency improvements. This research integrates Thermo-compressors (ejectors) and control valves into a Minimal Self-Recirculation (MSR) system model, aiming to enhance energy-saving performance. Through Computational Fluid Dynamics (CFD) simulations and Adaptive Neural Network (ANN) modeling, the study evaluates the system's energy-saving potential and operational adjustments. Key findings include the identification of optimal operating conditions for the Thermo-compressor and the establishment of a robust MSR system model, demonstrating significant energy savings and operational efficiency. The research contributes to the development of sustainable and cost-effective solutions for the paper industry's energy challenges. ENVIRONMENT
Technical Abstracts
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