Harry Parker

Overview of Raw Materials from Renewable Agricultural Resources*

Harry W. Parker, Ph.D., P.E.
Professor of Chemical Engineering
Texas Tech University, Lubbock, TX 79409-3121
(806)742-3553 Fax 742-3552
E-mail

Abstract

During the last two-thirds of the 20th century, petrochemicals have very significantly displaced materials derived from crops and from animal coproducts in applications such as detergents, paints, solvents and lubricants. This displacement was caused in part by the unique performance of petrochemicals, but lower production costs greatly facilitated the transition to petrochemicals. At the same time the productivity of our farms has vastly increased, so that 23 percent of our cropland is not utilized for crops. For this reason, there have been consistent efforts by USDA personnel and other research workers to develop new uses for agricultural products, and to maintain existing industrial uses for crops. With the exception of wood and cotton, these efforts have had only moderate success in reducing the number of under-utilized acres, and in increasing farm profitability.

Recent societal concerns have stressed factors such as depletion of nonrenewable resources, dependence in imported petroleum, the threat of global warming, and the search for environmentally-friendly products. Knowing the production costs of similar materials derived from either petrochemical sources or from agricultural crops is essential for rational consideration of these recently stressed societal concerns. /p>

History

Until the 19th Century essentially all organic materials used by men were based on crops and animals. Natural petroleum oil and bitumen seeps were the exception, that usage even has a Biblical citation, Genesis 6:14. Coal tars provided the first chemicals based on fossil fuels, and in 1857 William H. Perkin built the first commercial plant at Greenford Green, England, for aniline dyes which he had discovered (1). The displacement of vegetable dyes with synthetic dyes followed: alizarin in 1869, and indigo in 1897 (2). Both synthetic dyes caused the growth of crops for these vegetable dyes - madder for alizarin and indigo or woad for indigo - to essentially cease. These industrial dyes were discovered and developed in parallel with the establishment of organic chemistry as a science. This circumstance was the slow beginning of the displacement of agricultural materials by what we would now term petrochemicals.

The first petrochemical plant has been identified as the isopropyl alcohol plant built in Bayway, N.J., in 1919 by the company which is now known as Exxon (3). From this beginning, petrochemicals have come to dominate the markets for industrial organic materials and the resulting consumer products. The result has been decreasing opportunities for crop-based organic chemicals and polymers. This competition has been reviewed by the author recently (4), and the subject will be analyzed somewhat differently in this overview. Increasing public interest in renewable resources and concerns regarding global warming have added new dimensions to the tradeoffs between bio based products and petrochemicals. /p>

The Department of Agriculture, USDA, university research groups, crop and meat processing industries, producer groups, and individual entrepreneurs have provided continuing education, research and development activities to increase the use of agricultural materials as industrial products. This activity has been comprehensively reviewed in the 1992 Yearbook of Agriculture (5). Another publication, New Industrial Uses, New Markets for U.S. Crops, reviewing industrial uses of crops has been published by the Cooperative State Research, Education, and Extension Service of USDA (6). The Economic Research Service of USDA makes periodic reviews of industrial usage of agricultural products, the most recent of which is cited in the references (7).

The Alternative Agricultural Research and Commercialization Center, AARC, was established by the 1990 Farm Bill. Its purpose is to foster actual increased usage of agricultural products as industrial and consumer materials, particularly when processed in rural America. The establishment of AARC recognized some of the barriers to industrial utilization of agricultural materials identified in this paper, and AARC seeks to minimize these obstacles. By a variety of financial agreements AARC facilitates the actual production of industrial and consumer products from agricultural materials. These financial agreements are based on contractual agreements that AARC will be repaid in interest-bearing dollars and/or an equity position in the funded company for the funds which it has made available. AARC's evaluation of proposed projects also provides applicants an objective review of their proposed activity. This detailed AARC review has the potential of avoiding needless time and dollars spent on unfeasible projects by the applicants. To date, AARC has supported 37 projects with $15.3 million. For additional information regarding current AARC projects, or to obtain information concerning possible AARC participation in a particular project, the address given in reference (8)should be contacted.

Rational for Use of Agricultural Products As Industrial Materials

From the perspective of agriculture, having arable land in excess of that needed to grow food provides the rational for facilitating the use of agricultural products as industrial materials. In 1993 our nation had 464 million acres (187 million Ha) of arable land, of which 68 million acres (27.5 million Ha) are idle, in part, as a result of current agriculture policies and 65 million (26.3 million Ha) are used for pasture (9). These policy decisions regarding agriculture are being made anew in the writing of the '95 Farm Bill by a largely urban, Republican Congress. In 1992 it was reported that only 1.8 % percent of our population is rural (10). In the perspective of petrochemicals, this idle land is a relatively small potential source of organic chemicals. If it were possible to plant all of these under-utilized acres to soy at an average yield of 35 bushels per acre, with a oil content of 20 %, the result would be 3.2 billion pounds (1.45 Gg) of soy oil per year. This is about equal to our total domestic consumption of fats and oils for industrial uses, and it is under 2 % of the total petrochemicals utilized. Even so, the effective utilization of idle land is of great importance to rural Americans and to their representatives in Congress.

Environmental concerns frequently favor the displacement of petrochemicals with agricultural products. Many dedicated environmentalists are avidly encouraging use of these renewable resources. Many of them favor "annually renewable crops" such as kenaf for newsprint versus newsprint from trees, which are only renewable in the context of decades. Agricultural products are renewable resources, only when grown in a truly sustainable manner. Agricultural professionals, and also laypersons, have yet to reach a consensus regarding the meaning of the phrase "truly sustainable." Highly productive, present day agriculture relies heavily on petroleum and natural gas for fuel, nitrogen fertilizer, herbicides and insecticides. This fact can scarcely be circumvented.

In reality, convenient fossil energy, natural gas and petroleum, can be expected to remain abundant and economical for several decades and perhaps longer. Improved exploration and production technologies appear to be offsetting the decrease in remaining petroleum and natural gas resources on our planet (11). After most of our petroleum and natural gas reserves have been consumed, we can utilize less convenient, but very abundant, domestic fossil energy resources such as coal, lignite, western oil shale, and eastern black shale. Currently the technology exists to gasify coal, and then convert the resulting "syn gas" to most current petrochemicals via C-One chemistry, as well as to ammonia. Ammonia is essential as a nitrogen fertilizer to maintain current levels of productivity for many crops. Tennesees Eastman's plant in Kingsport, Tennesse, completed in 1983, is an example of this capability. This plant converts regional coal to 1.2 billion pounds per year of acetic anhydride.

The possibility of global warming has become another concern of society. Emission of carbon dioxide into the atmosphere as a result of consuming fossil fuel is a major source of "greenhouse" gases contributing to global warming. It appears that environmental activists and politicians have set goals for reduction of carbon dioxide emissions before a consensus about the seriousness of global warming has been reached by the appropriate scientists (12). In contrast, popular writers have proclaimed that the choice of least regrets should be made, and so the emission of fossil carbon dioxide should be reduced at this time (13). Use of plant materials instead of fossil fuels directly reduces the net emission of carbon dioxide into the atmosphere, since the growth of plants removed the same amount of carbon dioxide from the atmosphere as is released when the plant is consumed as fuel or as a organic chemical. There are several options for reducing carbon dioxide emissions into the atmosphere which may be more economic than substituting plant materials for fossil energy resources. These options include energy conservation, recycling, and increased utilization of nuclear, solar and wind energy.

Being environmentally friendly is another phrase associated with utilization agricultural products. In many (but not all cases) polymers based on agricultural materials are biodegradable, and so may be composted, instead of being incinerated or placed in landfills. Biodegradable polymers can also be produced from petrochemicals, if a major market for biodegradable polymers develops. It is perceived by some individuals that fewer harsh, toxic chemicals are used in processing agricultural products than in production of petrochemical products, hence they are more environmentally friendly. The chemical industry has demonstrated that as our knowledge of toxic and carcinogenic materials increases, reasonable steps can be taken to protect both workers and consumers. Vinyl chloride, PCB's, and benzene are established examples of these actions to mitigate risk of toxic materials.

Levels of Molecular Complexity

Agricultural products compete with petrochemical materials at three different levels of molecular complexity as follows:

Macromolecular structure - cotton, wood, natural rubber.
Molecular structure - paints, lubricants, detergents.
Energy and elemental chemical content - fuel ethanol, biodiesel, gasification, boiler fuel.

Agricultural products compete most effectively with petrochemicals when their macromolecular structures are retained during processing. One example is cotton, natural cellulose fibers which compete effectively with synthetic fibers for textiles. Wood continues to compete with various polymers in many industrial applications. About 10 times more timber is utilized than plastics per year. New technologies for refabricated wood products serve to keep wood competitive, even with the declining availability of large trees. Cellulose fibers recovered by rather expensive paper-making processes still dominate the paper industry.

Agricultural products are less competitive with petrochemicals when only their molecular structure is retained. A major example is natural rubber, which has about 25% of the rubber markets, primarily for tires. This dominance is primarily a matter of price, about 55õ/lb ($1.20/kg) for tropical rubber. Synthetic natural rubber is produced commercially. Domestic production of natural rubber from a desert plant, guayule, has been demonstrated. Guayule has not yet become economically competitive. Drying oils such as linseed can be directly utilized in oil-based paints. Other vegetable oils can be readily incorporated in alkyd paints. Oils such as castor and rapeseed are useful as speciality lubricants. Fatty acids from tallow and vegetable oils are effectively utilized in soaps, detergents, and as chemical intermediates. New opportunities for fats and oils exist in production of low VOV coatings and plastics. Some traditional modified agricultural products now find only limited markets due to performance and price constraints. These include the modification of cellulose into rayon and cellulosic plastics. The advantage of retaining the molecular structure of an agricultural product is being recognized by agricultural groups, for example, the results of a study sponsored by the American Soybean Association (14). The products recommended for further development retain much of the molecular structure of the soy oil or protein.

Agricultural products find competition with petroleum and petrochemicals most difficult when they are utilized only for their energy content and/or for the availability of organic carbon and hydrogen in them. The use of fermentation ethanol in transportation fuels depends on not being required to pay a portion of federal and state gasoline taxes on gasoline containing ethanol. Even so, production of MTBE was about 3-fold greater than ethanol for fuel in 1993. Agricultural interests are making considerable efforts to expand mandates and tax incentives for fuels based on agricultural products, to offset their inherent high cost relative to petroleum based fuels. Any biomass, such as wood, other plant materials, or municipal solid waste, can be gasified to synthesis gas - carbon monoxide and hydrogen. This synthesis gas can then be converted into almost any petrochemical via c-one chemistry. Experience has indicated thus far, that coal is a more economical and reliable source of organic carbon for gasification than plant materials, even municipal solid waste which has a negative value. Large-scale burning of intentionally grown biomass for commercial generation of electricity faces similar economic barriers with respect to coal as a fuel.

Fermentation processes also utilize the energy content of biomass materials. After the available byproduct molasses has been utilized in fermentation processes, the next most economical, domestic fermentation substrate is starch, primarily from corn. With the exception of fermentation ethanol discussed in the previous paragraph, most fermentation processes produce relatively high-valued food additives, for example citric acid at 75õ/lb ($1.65/kg), and pharmaceuticals. These markets will be dependent on demand and on the development of new biotechnology products. Increased markets for corn, via sale of starch for fermentation, will depend on these external factors. If hydrolysis of cellulose, contained in wood and plant residues, to produce fermentable sugars ever becomes economically attractive, the demand for starch as a fermentation substrate could decrease. Many unsuccessful efforts to economically hydrolyze plant materials for fermentable sugars have been documented in the past. For this reason many persons are skeptical regarding the present generation of biomass hydrolysis processes. Petrochemicals can also be utilized for fermentation feedstocks such as methanol, synthetic ethanol, and even alphatic hydrocarbons. The usual objective in these cases is single cell protein, SCP, for food and feeds. SCP has not received wide acceptance as a substitute for protein from oilseeds or animal products.

Apparent Barriers to the Use of Agricultural Products

The author has identified several barriers to the increased utilization of agricultural products for industrial materials in previous publications (15), (16). Some of these will be repeated in this present document. The cost of agricultural raw materials relative to petroleum and petrochemical intermediates generally favors petroleum. Corn starch is currently priced at 10õ/lb (22õ/kg) in large quantities. Recently, some experienced agri-industry representatives accepted 8õ/lb (17.6 õ/kg) as a low, but achievable price for corn starch. At 8õ/lb for starch carbon contained in it would have a value of 20õ/lb (44õ/kg). Organic carbon is available for under 8õ/lb from petroleum at $18/bbl or natural gas at $2.50/mcf.

The reliability of raw material supply is another limitation on using agricultural products. A company utilizing fossil fuels can effectively own a 20-year supply of raw materials having a well-defined quality. In contrast, the price and availability of agricultural products varies from year to year, and even month to month. The futures market and large infrastructure supporting major crops such as soy and corn minimizes some of these risks. New specialty crops are difficult to commercialize since many activities must be coordinated growing, processing, and marketing. Examples include kenaf, guayule, vernonia, and lesquerella. Seasonal availability of crops may limit effective utilization of processing facilities and require stockpiling a year's supply of raw materials and/or products. Cotton and sugar are examples of this circumstance.

Lack of vertical integration may limit development of new agricultural products. In contrast, an oil company may explore for oil, and then finally sell gasoline and other consumer products. Lack of vertical integration particularly limits marketing efforts for new products, since the marketing cost can not be assigned over all the production and manufacturing operations.

Conclusions

Based on the above analysis, markets for agricultural products which utilize the macromolecular structure of the product are stable, and research is needed primarily to retain the present market shares. Examples are wood products and cotton. Processes which utilize only the energy content of biomass have not been shown capable of competing with petroleum or even coal as an energy source or for an organic carbon source. Without mandated constraints on the emission of carbon dioxide from fossil fuels, biomass energy and carbon resources will remain uncompetitive with petroleum and coal. The mandate constraining use of fossil fuels would come in response to perceived concerns about global warming.

New and improved industrial products which retain much of the molecular structure of the agricultural material appear to offer the best opportunity for increased markets for agricultural materials. These applications include paints, lubricants, surfactants, and plasticizers. Increasing market share against existing products will not be easily accomplished. Research workers in USDA and other organizations are systematically developing these opportunities. Both existing domestic crops, primarily corn and soy, and new crops such as lesquerella, vernonia, meadowfoam, and others are being investigated.

Acknowledgments and Disclaimer

The author, as the former Director of the Office of Agricultural Materials in the Cooperative State Research Service, acknowledges the support of USDA as well as Texas Tech University in the research for and in the preparation of this document. It should be stressed that these institutions are not responsible for the content of this paper.

References

* This paper was presented in Session 56 - "Raw Materials from Renewable Agricultural Resources," Houston National American Institute of Chemical Engineers Meeting, March 19-21, 1995.

(1) Holmyard. E.J., "Dyestuffs in the Nineteenth Century," p.271, In Singer, C., E.J. Holmyard, A.R. Hdall, and T.I. Williams, Editors, A History of Technology, Vol. V, Oxford University Press, London, (1958).

(2) Holmyard, E.J., pp. 277-78.

(3) Wett, T. "How petrochemicals changed the world," Oil and Gas Journal 75th Anniversary Issue, p.425, Aug. (1977).

(4) Parker, H.W., "Biobased Products Versus Petrochemicals Scouting the Other Team," Biobased Products EXPO'94, Kansas City, Missouri, Dec. 5-7, (1994).

(5) Anon.(USDA), "New Crops, New Uses, New Markets 1992 Yearbook of Agriculture," Office of publishing and visual communications, USDA, (1992).

(6) Anon.(CSREES/USDA), "New Industrial Uses, New Markets for U.S. Crops: Status of Technology and Commercial Adoption," CSREES/USDA, (1993). (Call 202-401-4640 for a copy, as long as the present supply lasts.)

(7) Glaser, L., Coordinator, "Industrial Uses of Agricultural Materials - Situation and Outlook Report," #IUS-4, Economic Research Service, USDA, Dec., (1994).

(8) Alternative Agricultural Research and Commercialization Center, AARC, USDA, Washington, DC, 20250-0400, Telephone 202-690-1633, Fax 690-1655.

(9) Anon.(USDA), "Agricultral Statistics 1993," p. 348, USDA, Washington, DC, (1993).

(10) Anon.(USDA), p. 353.

(11) Fisher, W.L., "How Technology Has Confounded U.S. Gas Resource Estimators," Oil and Gas Journal, pp. 100-107, Oct. 24, (1994).

(12) Seitz, F. "Global Warming and Ozone Hole Controversies A Challenge to Scientific Judgment," George C. Marshall Institute, Washington, DC, (1994).

(13) Hawken, P. "The Ecology of Commerce," HarperCollins Publishers, New York, (1993).

(14) Montgomery, R.H., R.W. Unterreiner, C.E. Grabiel, and T.E. Doyle, "Executive Summary, Plastics, Wood Adhesives, Building Materials, Market Opportunity Studies for the American Soybean Association," Omni Tech International, Ltd. Midland, Michigan, (1994).

(15) Parker, Ref. #4.

(16) Parker, H.W., "Processing of Agricultural Products for Nonfood Uses Opportunities and Competitive Barriers," Paper 12a, National Summer Meeting of AIChE, Denver, August 21-24, (1988).