Pulp Production and Processing

High-Tech Applications

Valentin I. Popa

• Publisher: De Gruyter
• Year: 2020
• eBook ISBN: 9783110659214
• Edition: 2
• Topic: Technology & Engineering
• Subtopic: Chemistry
• Index: Chemistry

This book presents the aspects of cellulose obtained in correlation with its integration into the new concept of biorefining. The authors detail the individual steps of pulp manufacture as well as properties and fiber characterization techniques for paper, cellulose derivatives and processing by-products. This book is of interest to scientists and advanced students working in the fields of renewable resources and biorefining.

Chapter 1 Biorefining and the pulp and paper industry

Valentin I. Popa

“Gheorghe Asachi” Technical University of Iasi, Iasi, Romania

1.1 Introduction

The concept of biorefinery originated in late 1990s as a result of scarcity of fossil fuels and increasing trends of use of biomass as a renewable feedstock for the production of nonfood products. The term of “Green Biorefinery” was first introduced in 1997 as “Green biorefineries represent complex (to fully integrated) systems of sustainable, environmentally and resource-friendly technologies for the comprehensive (holistic) material and energetic utilization as well as exploitation of biological raw materials in form of green and residue biomass from a targeted sustainable regional land utilization.”

According to US Department of Energy (DOE) “A biorefinery is an overall concept of a processing plant where biomass feedstocks are converted and extracted into a spectrum a valuable products.” The American National Renewable Energy Laboratory (NREL) defined biorefinery as “A biorefinery is a facility that integrates biomass conversion process and equipment to produce fuels, power and chemicals from biomass.” These definitions of biorefinery are analogous to today’s integrated petroleum refinery and petrochemicals industry to produce multitude of fuels and organic chemicals from petroleum [1].

However, we think that we have a priority because we have introduced this concept in the paper [2]:

In our days, the idea that vegetable biomass represents a source of liquid fuel and of different new materials has led to the development of various research programs in this field. Our investigations in this direction are based on the following premises: (1) all kinds of vegetable biomass include almost the same components; (2) the macromolecular compounds existing in the vegetable biomass incorporate biosynthesis energy, and their conversion to useful products seems to be considered; (3) the complex and total processing technology may be modulated depending on the chemical composition of the vegetable source, as well as on the utilization of the obtained chemical compounds. The possibilities of complex processing of soft- and hardwood bark, agricultural wastes, and some energetic cultures of Helianthus tuberosus and Asclepias syriaca are exemplified.

In order to face the present state of affairs, the manifested tendency is that of adopting the existing classical technologies of carbo- and petrochemical fields in processes of converting biomass into products possessing energetic and/or chemical value. The technology of integral and complex valorization of biomass has been proposed is to be performed on several stages and modules, depending on the chemical composition of the available vegetal resources and on the corresponding field of application for the obtained products as well.

A plant for the fractionation and refining of biomass and to use of its entire components is a “biorefinery” plant, will have to display a high level of process integration and optimization to be competitive in the near future. Forest products companies may increase revenue by producing biofuels and chemicals in addition to wood, pulp, and paper products in a so-called integrated forest biorefinery (IFBR). The concept of an IFBR is being advanced by a number of investigators who envision converting cellulose, hemicelluloses, and lignin from woody biomass, dedicated annual crops, industrial and municipal waste in bioenergy, and basic chemicals [3, 4, 5].

A pulp mill has excellent prerequisites to be the base for a biomass-based biorefinery: large flow of raw materials (wood and annual plants), existing process equipment, and good process knowledge. The key strengths of the pulp and paper industry are the wood and biomass sourcing along with the logistic infrastructure, a sustainability existing base of integrated production, and the high efficiency and experience in combined heat and power generation. The industry has unique capabilities in handling very large volumes of biomass, and the synergies in logistics and energy integration are significant. Therefore, biorefining and bioenergy fit well into the integrated business model of forest products companies.

The current chemical pulp process use approximately 50% of the organic raw material in the production of paper pulp; the remaining 50% is combusted in the recovery boiler to produce steam. A modern energy-optimized pulp mill has a substantial excess of energy/steam. This excess can be utilized in several different ways:

• The first is to produce electrical power.
• The second is to replace the recovery boiler with a black liquor gasification unit to produce syngas.
• The third is to extract some lignin from the black liquor and sell it as a new product to be used as fuel or raw materials for biobased products.
• The fourth is to attract the other external sources of biomass or wastes and to process them with the aim of obtaining fuels and chemicals [6].

In the pulp mill of tomorrow, the hemicelluloses and extractives, dissolved in process streams, could also be extracted and used as chemical raw materials. As a consequence the chemical pulp mill could be transformed into an integrated biomass biorefinery, producing different chemicals besides traditional pulp and papers [2].

At the same time, the utilization of biomass as a renewable raw material may have the following advantages: (1) reduced dependence on imported fossil oil; (2) reduction in greenhouse gas emissions; (3) building on the existing innovation base to support new developments; (4) a bioindustry that is globally competitive; (5) the development of processes that use biotechnology to reduce energy consumption and the use of nonrenewable materials; (6) the creation of jobs and wealth; (7) the development of new, renewable materials; (8) new markets for the agriculture and forestry sectors, including access to high-value markets; (9) underpinning a sustainable rural economy and infrastructure; and (10) sustainable development along the supply chain from feedstocks to products and their end-of-life disposal.

1.2 Possibilities of biorefining implementation into the pulp industry

Examples of fractionation technologies are several biomass pulping processes that are common practice in the pulp and paper industry (e.g., kraft pulping, sulfite pulping, soda pulping, organosolv pulping, etc.). Here, the biomass is essentially fractionated into cellulose (for paper) and black liquor, a waste stream that predominantly contains residual carbohydrates and their degradation products (e.g., from the hemicelluloses), partly degraded lignin, and inorganics from the pulping process. The main application to date of this black liquor is combustion for heat. In addition, lignin and lignin-containing residues are large side streams from the pulp and paper industry and from biorefineries that use the carbohydrate fraction of the biomass, for example, for the production of bioethanol. Globally ~ 50 Mt per year of lignin originates from the pulp and paper industry, predominantly from kraft-, soda-, and sulfite-pulping of softwood, hardwood, and agricultural residues such as straw, flax, and grasses. Only 1 Mt is used for commercial purposes including lignosulfonates from sulfite pulping and 0.1 Mt as (chemically modified) kraft lignins from kraft pulping [7].

At present, most of these sulfur-containing lignin streams are combusted for generating power and/or heat, an application with very limited added-value. These sizable amounts of lignin are in principle available for valorization into chemicals and performance products. New developments in soda-pulping technology have resulted in sulfur-free lignins from herbaceous types of biomass such as straw and grass [8, 9].

Furthermore, large amounts of (hydrolytic) lignin will be produced from future bioethanol-based biorefineries by processes such as steam explosion and organosolv pulping. The first is a thermomechanical treatment that uses sulfuric acid for the hydrolysis and steam-explosion for breaking up the fibrous biomass structure. Organosolv pulping of hardwood, grasses, and straw leads to a high-quality lignin that is essentially sulfur free. The biomass is fractionated into lignin, cellulose, and a hemicelluloses containing-side stream. Generally, the hydrolytic lignins are the main fraction in the side stream that originates from the processing of wood and agricultural residues for transportation fuels and chemical building blocks.

Taking into account the utilization of different biomass sources as raw materials in a complex integrated pulp mill producing bioproducts and biomaterials, after our opinion we have to consider the following aspects: (1) all kinds of vegetable biomass contain almost the same main compounds; (2) the macromolecular compounds existing in the biomass incorporate biosynthesis energy, and their conversion to useful products seems to be economical; and (3) the complex and total processing technology may be modulated depending on the chemical composition of the biomass sources, as well as on the utilization of the obtained chemical compounds [2].

Thus, the specific objectives of this proposal have to be the following:

1. Identification, quantification, and characterization of resources from chemical composition point of view.
2. Separation and establishment of optimal conditions for fractionation using an original scheme that allows isolating chemical compounds as a function of their structure and raw material accessible to be processed (Fig. 1.1). Conventional and nonconventional extraction procedures will be used.
3. Characterization of isolated products; comparative studies of extraction methods will be carried out; correlation of the characteristics with the possibilities of utilizing the obtained products; establishing potential applications.
4. The elaboration of sequential technological procedures to recover separated compounds with the aim of transferring them to the pilot-scale level.
5. Evaluation of the...

Table of contents

• Title Page
• Copyright
• Contents
• Chapter 1 Biorefining and the pulp and paper industry
• Chapter 2 Pulping fundamentals and processing
• Chapter 3 Fibrous raw materials from agricultural residues
• Chapter 4 Chemical pulp bleaching
• Chapter 5 Recent advances in processing of biomass feedstocks for high added value outlets through bio-greening pathways
• Chapter 6 Valuable biobased products through hydrothermal decomposition
• Chapter 7 Catalytic conversion of hydroxymethylfurfural and levulinic acid to biomass-based chemicals
• Chapter 8 Chemistry and physics of cellulose and cellulose substance
• Chapter 9 Wood- and nonwood fibers in fibrous structures with common and high-tech applications
• Chapter 10 Cellulose-based hydrogels: design, structure-related properties, and medical applications
• Chapter 11 Nanocelluloses: preparations, properties, and applications in medicine
• Chapter 12 Ionic derivatives of cellulose: new approaches in synthesis, characterization, and their applications
• Chapter 13 Novel methods to control the optical anisotropy of cellulose esters
• Index