Comprehensive analysis and optimization of waste heat recovery and utilization in paper drying process

This study provides a comprehensive analysis and optimization of waste heat recovery in the paper drying process, which is an 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 study integrates Thermo - compressors (ejectors) and control valves into a minimal self-recirculation (MSR) system model to boost energy-saving performance. It assesses the system's energy-saving potential and operational adjustments through computational fluid dynamics (CFD) simulations and adaptive neural network (ANN) modeling. The study determines optimal operating conditions for the Thermo-compressor, establishes a robust MSR system model, and finds that the system operates efficiently at intake pressures of 260–380 kPa and flow rates of 1500–5000 kg/h. The optimized MSR system offers significant economic benefits, with a steam recovery rate of approximately 15 %–16 %.The research contributes to the development of sustainable and cost-effective solutions for the paper industry's energy challenges.