Chapter 3
Opportunities for the Cost-Effective Production of Biobased Materials 1
Helena L . C h u m and Arthur J. Power 1
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Chemical Conversion Research Branch, Solar Energy Research Institute, 1617 Cole Boulevard, Golden, C O 80401 Arthur J . Power and Associates, Inc., 2360 Kalmia Avenue Boulder, C O 80304
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There are a number of evolving technologies that convert wood, wood waste, agricultural residues, and recycled fibers into new biobased materials such as composites that incorporate additional plastics and other materials. The use of non-woven technologies to produce mats that can be molded into shaped parts is very common in the composites industry. The direct use of the thermally treated fibers is possible; however, chemically modified fibers improve the chemical, physical, and biological properties significantly. To illustrate the potential of biobased fibers in composites, a technoeconomic analysis of wood acetylation is presented. Worldwide trends in the use of chemically modified wood products are described in relation to their possible market penetration relative to the current products.
This contribution is based on a few recent reviews of biobased materials (1-3), literature and patent searches, analysis of market trends of the North American forest products industry (e.g., 4) compared to those of a few other countries (e.g., 1,5), and a detailed technoeconomic assessment of one option of chemical modification of fibers, the acetylation of wood. Several chapters in this book are also excellent sources of current literature and trends, principally for the use of recycled fibers. This chapter discusses current utilization trends for value-added forest products, such as those produced from chemical modifications. Some of these processes are becoming technically feasible and are beginning to penetrate the marketplace, primarily in Japan. New products need to be cost-effective and produced in an environmentally benign way. The product properties must also be reproducible, regardless of possible variations in the quality of the incoming feedstocks, a characteristic that impacts wood natural polymer feedstocks more than petroleum-derived plastics. A 0097-6156/92ΑΜ76-0028$06.00/0 © 1992 American Chemical Society
In Emerging Technologies for Materials and Chemicals from Biomass; Rowell, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1992.
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Cost-Effective Production ofBiobased Materials
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deep understanding of the materials industry (both petroleum-derived and forestbased) in the particular country or region is essential, since the overall assessment of the effects of the new process (or product) needs to be carried out. To displace a high-sales, low-cost material produced in a process that operates profitably in an integrated industry is difficult. In most cases, the capital has been depreciated already and the plants can continue to operate profitably for a reasonable time. One needs to search for opportunities in the industry, such that the materials that we want to produce from biomass or wastes can either be substantially less expensive (both in capital and operating costs) or provide some special market advantages to the investing company. The risk of the new technology needs to be largely reduced, for instance, through joint funding between government and industry, to a point where industry can invest in a new venture and operate the plant profitably. Cradle-to-Grave Materials Cycle Analysis The materials cycle includes drilUng/mining/harvesting raw materials such as oil, rock, coal, sand, or renewable resources. Through extraction, refining, or processing, these raw materials are converted into various bulk materials such as chemicals, metals, cement, fibers,and paper. These in turn can be made into engineering materials such as plastics, alloys, ceramics, crystals, and textiles through appropriate processing. The engineering materials are then fabricated into products, devices, structures, and machines, through design, manufacture, and assembly. The materials have to be disposed after their useful service life. At each step of the materials cycle residues are generated, which need to be minimized. The materials cycle thus includes all associated emissions to the biosphere from each individual step on the way to the consumer products as well as post-consumer use. In the disposal area, many alternatives exist, such as landfill, reuse, recycle, and recovery of materials and energy. Many of these strategies are still under development. Analyses of the complete life cycle of the product are becoming more common, albeit yet imprecise, since there are uncertainties in many of the assumptions used (e.g., references 6,7). Uncertainties exist in data gathering on the processes themselves (substantial proprietary data). In addition, the existing processes are not static, and the improvements have to be taken into account in a timely manner. Discrepancies between results of current comparative analyses by different industrial groups can be explained by using technologies at different developmental stages. The product recycle rate that can be achieved is another variable, as is the degree of landfill degradation that will result if that were the chosen option for disposal of that product. A total life cycle analysis that includes the raw materials, process, and all associated environmental costs is desirable before reaching the decision on what is the best material for a given application. Society may move toward such a decision-making process, different from the current low (or acceptable) cost to the producer or consumer. Any analysis based on our current knowledge will only
In Emerging Technologies for Materials and Chemicals from Biomass; Rowell, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1992.
Downloaded by PENNSYLVANIA STATE UNIV on August 6, 2012 | http://pubs.acs.org Publication Date: December 4, 1992 | doi: 10.1021/bk-1992-0476.ch003
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MATERIALS AND CHEMICALS FROM BIOMASS
provide a partial answer, which needs to be updated periodically as new knowledge is developed, since these issues affect major industrial sectors, municipalities, and government in the United States. Better-defined calculation methodology will continue to emerge. The size of the envelope of the cradle-to-grave analysis is important, and it should be recognized that we know progressively less about the second, third, and higher order impacts, which need to be considered as the envelope gets bigger. Thus, it is more difficult to quantify effects such as greenhouse and ozone layer damage. Nevertheless, all of these factors influence market decisions on what products to make, how to dispose of them, or better yet, how to design a product life cycle in such a way that it moves from one useful application into another, until its final environmentally acceptable disposal. Thus, reutilization of waste fibers through other applications that maintain the material in useful life for another 5-10 years, and that are followed by an environmentally acceptable disposal (or yet another use) are important It is, however, abundantly clear that our society needs and will continue to need inputs of virgin renewable materials, synthetic plastics, and their combinations. Use of renewable resources for materials will certainly have very little impact on the carbon cycle provided that 1) the energy use in the production process is small and not fossil fuel derived, and 2) the environmental impact of the process is small and minimizes energy/materials input. A l l materials have finite useful life cycles, but the released carbon from renewable resources can be fixed again in a sustainable way by the planted forests, in a short time. Therefore, the use of renewables coupled with a sustainable environmentally sound forest production and management program can have a significant positive effect on the carbon cycle, reducing the net increase in atmospheric carbon dioxide. Plastics Industry The plastics industry is complex. It is intimately related to the chemicals/petroleum refining industries, which responded to the globalization of world markets by becoming international in scope. The chemicals industry is operating profitably in the United States where many of the chemicals operations have consolidated over the past five years (8), with a concomitant substantial increase of foreign investments in this sector of the economy and an associated trade surplus. The plastics industry is moving today towards value-added operations, which could displace, in the materials area, a number of the conventional wood-based materials in the buildings and construction area, and in the commodities area, low-value plastics production. The total resins/plastics volume (includes miscellaneous plastic products) was 58 billion lb in 1988 in the United States. In the past 50 years of the domestic plastics industry, a growth of more than 50 billion lb has been achieved, primarily because of the production of better quality and more durable plastics (9). The value of these shipments was $87 billion in 1988 (10). Key applications include
In Emerging Technologies for Materials and Chemicals from Biomass; Rowell, R., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1992.
3. CHUM & POWER
Cost-Effective Production of Biobased Materiah
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packaging (31%), construction and buildings (22%), and consumer and institutional products (10%). The U . S. organic chemicals industry produces about 320 billion lb yearly with a value of about $110 billion (11). Energy profiles for plastics (72), which include raw materials extraction, processing into refined materials, and fabrication into finished products, range from 40,000 Btu/lb for high density polyethylene (HDPE), polypropylene (PP), polyvinyl chloride (PVC), urea formaldehyde (UF), and resins to 90,000 Btu/lb for nylon-6,6. Plastics are lightweight and finished products consume a relatively low amount of energy per unit Forest-products Based Industries The paper and paperboard industry in the United States produced 130 billion lb in 1986, with a total sales value of $75 billion (75). In 1988, the apparent per capita consumption of these products was 700 lb in the United States versus an average world figure of 100 lb. A n additional penetration of 9 billion lb was achieved by 1988, thus bringing the U.S. production to 139 billion pounds. This constitutes a significant fraction of the worldwide production of 453 billion lb (74). The production of lumber, plywood and veneer, and panels in similar units was 131 billion lb (75,76), with a value of shipments of $56 billion (1986). Thus, the forest-products industry expressed as the sum of these two industry segments shipped well over 260 billion lb in products (much more than the equivalent raw materials to manufacture them) and had a combined value of more than $130 billion. Energy profiles for wood products (72), which include raw materials extraction, processing into refined materials, and fabrication into finished products, are 4,00010,000 Btu/lb for pulpwood, veneers, recycled boxboard, and furniture, in order of increasing energy of manufacture; 19,000 Btu/lb for unbleached kraft paper, and 25,000 Btu/lb for bleached kraft paper. Wood is
