Theoretical analysis of LC-refining - pressure screening systems in TMP.

Area of Science:

• Pulp and Paper Manufacturing
• Mechanical Pulping
• Energy Efficiency in Chemical Engineering

Background:

• Low-consistency (LC) refining is known to reduce energy consumption in thermomechanical pulping (TMP).
• The precise function of LC refining within TMP systems remains under-investigated due to challenges in industrial-scale conception and pilot-scale practicality.
• Understanding LC refining's role is crucial for optimizing TMP production efficiency.

Purpose of the Study:

• To model and analyze the impact of LC refining within TMP systems.
• To evaluate the influence of key operational variables on refining performance.
• To compare the behavior and effectiveness of different refining system configurations.

Main Methods:

• Utilized pressure screening and LC refining models to simulate fibre length distributions.
• Developed correlations to predict refining power requirements.
• Modeled three distinct refining system configurations for analysis.
• Collected and compared industrial-scale TMP sub-system data with simulation outcomes.

Main Results:

• Simulations revealed the impact of variables like reject ratio, refiner gap, and refining net-power.
• Generated performance curves for length-weighted average fiber length to assess system behavior.
• Industrial data comparison showed simulation model relative errors ranging from 0-18% for predicted variables.

Conclusions:

• The study successfully modeled LC refining in TMP systems, providing insights into its energy-saving potential.
• Simulation results were validated against industrial data, confirming model accuracy.
• Findings support the integration of LC refining for enhanced energy efficiency in mechanical pulp production.