Eucalyptus Kraft Pulp Refining

Frontmatter

Chapter 1. Introduction

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Chapter 2. The Beautifull History of Paper

Abstract

In this chapter, the most relevant points in the history of paper are presented, in particular those related to the evolution of devices for “beating” the fibrous material, preparing it to obtain paper. The facts are reported from the invention of paper in ancient China and following the dispersion of knowledge of how to produce paper reaching Europe and the Americas, as well as later developments to the use of wood as a fiber front.

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Chapter 3. The Wood Pulping Processes

Abstract

This chapter presents the basic processes for obtaining pulp from wood. The high-performance processes (mechanical pulping) are briefly described and, in more detail, the chemical kraft process, which is the central theme of this book. The effects of the pulping process on the characteristics of the pulps produced and how such effects condition the quality characteristics of the papers are also discussed in this chapter.

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Chapter 4. The Modern Paper

Abstract

In this chapter, the main properties that define the usage behavior of different types of paper are presented and discussed. For each of the groups of paper properties, the cause-effect relationships are presented, that is, how the characteristics of the papers, which are dependent on the characteristics of the fibers and how these are modified during refining, determine the properties of these papers.

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Chapter 5. Wood as Raw Material Source

Abstract

In this chapter, a brief history of the use of wood as a source of fiber is presented, in addition to considerations on the use of wood with special attention to eucalyptus woods and hardwoods, as these characteristics are important both in defining the quality of the pulps obtained from these woods and in the behavior and responses of the pulps during refinement.

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Chapter 6. The Fiber Cell Wall

Abstract

In this chapter, the multilayered fibrillar structure of the fiber cell wall is presented, with discussions focusing on the structural modifications (fibrillations) caused by the refining action. The intensity and amount of these structural changes in the fiber wall determine the degree of refining, attributing the desired characteristics to the paper produced.

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Chapter 7. The Pulps (Fibers) Characteristics

Abstract

The characteristics of the pulps, in particular their chemical and anatomical characteristics, are discussed in this chapter with special attention to the relationships between the characteristics of the fibers and the definition of the properties of the pulps that characterize the desired properties in papers.

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Chapter 8. Refining the Chemical Pulps

Abstract

After presents a brief description of the refiners evolution, this chapter focuses on what happens inside the refiners, that is, on the mass flow distributions inside the refiners, on how the flakes in suspension are captured by the bars of the refiners’ discs, and how energy is transferred to the pulp causing the desired changes in the fibers in suspension.

The effects of refining on fibers are described and classified according to the structural changes caused to the fibers as well as according to the direct effects of these changes on the properties of the paper produced. Effects on paper machine runability are also presented and discussed.

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Chapter 9. The Refining Models or “Theories”

Abstract

The main theoretical models developed to describe the refining action of the pulp and explain the refining behavior in the development of the properties of refined pulps are presented in this chapter. The different models, also known as refining theories, are presented in chronological order, facilitating the visualization and understanding of the conceptual differences introduced by the different models over time (evolution of the refining “theories”).

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Chapter 10. Refining Operating Variables

Abstract

The effects of operational refining variables on the structural modifications of eucalyptus pulp fibers are presented one-by-one based on studies carried out in a refining pilot plant. In this way, it is possible to identify the most important operational variables, in terms of their direct effects on the desired quality of the refined pulp. The beating process in laboratory is also described considering the most usual laboratory beaters.

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Chapter 11. Refining Process Control

Abstract

The most used forms for the operational control of the chemical pulp refining process are presented and commented in this chapter.

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Chapter 12. Refining Strategies

Abstract

The refining strategies most used by the industry are presented and discussed in this chapter. Experimental results obtained for eucalyptus pulp in pilot refining installations are presented for both single-pass refining and series refining (multiple passes). There are presented and discussed results from refining mixtures of eucalyptus pulps with softwood pulps, also obtained in a pilot plant and simulating both separate refining and joint refining for different levels of pulp mixtures. Pulp fractionation strategies as well as alkaline chemical treatments (fiber swelling) are also discussed in this chapter.

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Chapter 13. Refining Process Optimization

Abstract

The refining optimization considering obtaining the desired result in the properties of the refined pulp with the lowest possible energy consumption is discussed in this chapter. Based on the results and discussions of the evaluation of operational variables, the most suitable strategy is proposed, which considers the use of the lowest intensity and highest possible refining consistencies.

The missing variable in models based on refining intensity is identified and described. It is related to the retention time of the pulp in the refiner and is attributed to the flocculation characteristics of the fibers. A new way of designing the discs (configuration) is presented to allow increasing the cutting length of the discs, generating lower refining intensities.

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Backmatter