Energy Efficiency Analysis of a High Consistency Refiner in Thermo- Mechanical Pulping Process

Thermo-mechanical pulping (TMP) as a subdivision of the refiner-based mechanical pulping is one of the most energy-intensive processes in which the main procedure is carried out during the refining process. In this study, a simulation model is developed to estimate the energy efficiency of the refining process for the long-term period. A Simulation model is obtained for long-term analysis by further developing the MATLAB Thermo-mechanical pulping simulation toolbox. The developed model implements the effect of refiner plate erosion on refining behavior. This model is utilized to predict two essential variables for refining energy efficiency calculation, which are refining motor-load and generated steam. The conventional variable for presenting refining energy efficiency is refining specific energy consumption(𝑅𝑆𝐸𝐶), which is the ratio of the refiner motor load to throughput. This is while in this study, a new variable as corrected refining specific energy consumption(𝐶𝑅𝑆𝐸𝐶) is introduced and practiced for better representation of the refining energy efficiency. In the calculation process of the 𝐶𝑅𝑆𝐸𝐶, recovered energy from refining generated steam is considered as a useful energy output to acquire a better variable illustrating the refining process from an energy perspective. This heat in the studied case is used for the district heating network. The developed model results in 160% and 78,75% improvement in simulation model determination coefficient and error, respectively. Utilizing the developed model and hourly district heating demand for 𝐶𝑅𝑆𝐸𝐶 calculation, results prove a 22% annual average difference of 𝐶𝑅𝑆𝐸𝐶 and 𝑅𝑆𝐸𝐶.