ON THE SPECIFIC ENERGY CONSUMPTION IN MECHANICAL PULPING

Research and development (R&D) of mechanical pulping processes has been active for decades, earlier mainly with the intention to improve quality and increase the amount of produced pulp but lately to decrease specific energy consumption (SEC) without loss in pulp quality. Many different approaches have been made to tackle the energy saving challenge but no clear scheme for progress has been given. This paper presents a framework for clarifying the SEC in mechanical pulping. It can be utilized when planning R&D of energy saving technologies. The framework is based on the generally approved hypothesis that the higher the intensity of mechanical work made on wood material the higher is the efficiency of desired work. However, the analysis took into account the constraint on the intensity not to destroy the fibers. Additionally, the framework was based on the fact that mechanical properties of native fibers are widely distributed and that intensity of work provided by mechanical pulping equipments is also distributed. By operating with the distributions under the constraints the outcome of the random pulping process can be revieved from the SEC point of view.