1 0 0 w 6.f 7 3 0 8- 8 9 1 k- Pyrolysis Oils from Biomass b 1/ 2 0 1 0. 1 oi: d 8 | 8 9 1 0, 3 er b m e pt e S e: at D n o ati c bli u P 1 0 0 w 6.f 7 3 0 8- 8 9 1 k- b 1/ 2 0 1 0. 1 oi: d 8 | 8 9 1 0, 3 er b m e pt e S e: at D n o ati c bli u P 376 ACS SYMPOSIUM SERIES Pyrolysis Oils from Biomass Producing, Analyzing, and Upgrading Ed J. Soltes, EDITOR 1 0 0 w Texas A&M University 6.f 7 3 0 8- Thomas A. Milne, EDITOR 8 9 k-1 Solar Energy Research Institute b 1/ 2 0 1 0. 1 oi: d 8 | Developed from a symposium sponsored by 8 9 the Cellulose, Paper, and Textile Division 1 30, and the Division of Fuel Chemistry er b at the 193rd Meeting m e pt of the American Chemical Society, e S e: Denver, Colorado, at D April 5-10, 1987 n o ati c bli u P American Chemical Society, Washington, DC 1988 Library of Congress Cataloging-in-Publication Data Pyrolysis oils from biomass producing, analyzing, and upgrading. (ACS Symposium Series; 376). 01 Developed from a symposium sponsored by the 0 Cellulose, Paper, and Textile Division and the Division of 6.fw FCuheelm Cichael mSiosctriyet ayt, Dtheen v1e9r3,r Cd oMloereatdino,g Aopf rtihl e5 -A1m0,e 1ri9c8a7n. 7 3 8-0 Includes index. 8 9 Bibliography: p. 1 k- b 1. Biomass energy—Congresses. 2. Pyrolysis— 21/ Congresses. 3. Hydrocarbons—Congresses. 0 1 0. I. Milne, Thomas Α. II. American Chemical Society. 1 Cellulose, Paper, and Textile Division. III. American oi: Chemical Society. Division of Fuel Chemistry. IV. Title. d V. Series. 8 | 8 TP360.P95 1988 662'.8 88-24172 19 ISBN 0-8412-1536-7 0, 3 er b m e ept Copyright © 1988 S e: American Chemical Society at D n All Rights Reserved. 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McGinniss w 6.f Merck Sharp & Dohme Research Battelle Columbus Laboratories 37 Laboratories 0 8- Daniel M. Quinn 8 9 Harvey W. Blanch 1 University of Iowa k- University of California—Berkeley b 1/ 2 10 Malcolm H. Chisholm James C. Randall 10. Indiana University Exxon Chemical Company oi: d 8 | Alan Elzerman E. Reichmanis 98 Clemson University AT&T Bell Laboratories 1 0, er 3 John W. Finley C. M. Roland mb Nabisco Brands, Inc. U.S. Naval Research Laboratory e pt Se Natalie Foster e: Lehigh University W. D. Shults at D Oak Ridge National Laboratory on Marye Anne Fox cati The University of Texas—Austin Geoffrey K. Smith ubli Rohm & Haas Co. P Roland F. Hirsch U.S. Department of Energy Douglas B. Walters National Institute of G. Wayne Ivie Environmental Health USDA, Agricultural Research Service Michael R. Ladisch Wendy A. Warr Purdue University Imperial Chemical Industries Foreword The ACS SYMPOSIUM SERIES was founded in 1974 to provide a medium for publishing symposia quickly in book form. The format of the Series parallels that of the continuing ADVANCES IN CHEMISTRY SERIES except that, in order to save time, the papers are not typeset but are reproduced as they are submitted 1 0 0 by the authors in camera-ready form. Papers are reviewed under w 6.f the supervision of the Editors with the assistance of the Series 7 03 Advisory Board and are selected to maintain the integrity of the 88- symposia; however, verbatim reproductions of previously pub 9 k-1 lished papers are not accepted. Both reviews and reports of b 1/ research are acceptable, because symposia may embrace both 2 10 types of presentation. 0. 1 oi: d 8 | 8 9 1 0, 3 er b m e pt e S e: at D n o ati c bli u P Preface PROLYSIS OF BIOMASS HAS undergone a technological renaissance in the past decade, thanks to new concepts and processes for high oil yields, new analytical techniques to decipher the mechanisms of formation and constitution of the oil, and catalytic approaches to upgrading the oil fuel used for transportation. Governments have given priority to pyrolysis and direct liquefaction, following bench and pilot success in gasification and indirect liquefaction, to offer industry concepts for renewable liquid 1 0 0 fuels, particularly premium fuels. Following the Workshop1 on Fast pr 6. Pyrolysis in 1980, and a series of liquefaction workshops in Canada2 in 7 3 0 1980, 1982, and 1983, it seemed timely to convene scientists and 8- 8 engineers from North America and elsewhere to report on the present 9 1 k- progress in integrated pyrolysis oil production, characterization, and b 1/ upgrading studies. 2 0 0.1 As the book name implies, we attempted to bring together specialists 1 oi: to present the state of the science in the complete fuel cycle, from d feedstock to upgraded liquid fuels suitable as replacements for 8 | 8 petroleum-derived fuels. The introductory chapter contains a discussion 9 1 0, of biomass pyrolysis and its place in a renewable fuel economy. Contri 3 er butions to this book were received from five countries, a fact indicating mb the widespread interest in this conversion option for biomass, and per e pt mitting the enhancement and establishment of collaborative efforts. e S e: At the time this preface was written, the U.S. newspapers reported a Dat two-year low in crude oil prices ($15/Bbl), fleet auto efficiency standards on were being relaxed, and oil imports were rising steadily. At the same cati time, through perhaps a short-term statistical fluctuation in rainfall, the ubli public was finally becoming aware of the implication of the real, long- P term rise in C0 levels from deforestation and the burning of fossil 2 fuels. Perhaps the promise of a renewable source of liquid transporta tion fuels, coupled with extensive reforestation, as mitigators of the rise in C0 levels, will spur progress in the conversion of C0, through pho 2 2 tosynthesis, to plant materials. Such plant materials could provide facile and economic routes to substitutes for fossil-based fuels, chemicals, and biobased materials. 1. Diebold, J. P., Editor. Proceeding? of the Specialists Workshop on the Fast Pyrolysis of Biomass. Copper Mountain, Colorado, Oct. 20-22 SERI/CP-622-10%. 2. ENFOR Program and National Research Council of Canada. Biomass Liquefaction Specialists' Review Meetings in Toronto, Aug. 13, 1980; Saskatoon, Feb. 16-17, 1982; and Sherbrooke, Sept. 29-30, 1983. xi We thank the sponsoring divisions and all contributors to this volume and hope that their results will foster both interest in, and sup port of, continuing work on the fascinating chemistry and engineering of biomass pyrolysis, oil characterization, and upgrading for many uses. ED J. SOLTES Texas A&M University College Station, TX 77843 THOMAS A. MILNE Solar Energy Research Institute Golden, CO 80401 1 0 0 pr 76. July 5, 1988 3 0 8- 8 9 1 k- b 1/ 2 0 1 0. 1 oi: d 8 | 8 9 1 0, 3 er b m e pt e S e: at D n o ati c bli u P xii Chapter 1 Of Biomass, Pyrolysis, and Liquids Therefrom Ed J. Soltes Department of Forest Science, Texas Agricultural Experiment Station, Texas A&M University System, College Station, TX 77843-2135 Renewable biomass (harvest and process residues in forestry and agri cultural operations, specific terrestrial or aquatic crops grown for fuel, 1 00 often animal wastes, refuse derived fiber, etc.) represents an important h c energy resource in the United States, with future potentials especially 6. 7 important as fossil fuels are depleted (1). Biomass is however generally 3 8-0 poorly suited for direct energy use, with pretreatments necessary for 8 altering physical and chemical form. Moisture content can be in excess of 9 k-1 50%, so costs of collection, transportation, and energy conversion become b relatively inefficient. Further, biomass availability (e.g., from row crops) is 1/ 2 sometimes seasonal, so storage is necessary. As biomass can spoil, it has to 0 0.1 be covered and processed soon after receipt. Fortunately, thermal oi: 1 aconnd vcearns iocno npvreortc ebsisoems aasrse isnotmo eswtahbalte ,i nssteonrasibtliev ea ntod ttyrpane,s pfoorrmta balned esnhearpgey, d 8 | forms, and in physical or chemical forms that can be used in higher 98 efficiency energy conversion processes developed for liquid petroleum, coal 1 0, and natural gas. Under pyrolysis process conditions, a liquid tar (pyrolysis ber 3 oil) cWanh yb e lipqruoiddu? cedI t wchainch bcea na breg uuepdg rtahdate d thtoe lipqruiindc iepnagl inaed vfauneltsa ge(2 ).o f m e petroleum is that it is a liquid (3): liquid fuels, besides being energy ept dense, are especially easy to store, transport and meter, thus being really S e: the only choice for transportation fuels. Biomass conversion processes at (specifically pyrolysis) which have potential for producing liquid fuels, D n especially liquid fuels that can be direct replacements for gasoline or diesel o ati engine fuels, are then of much interest. c bli u P The Nature of Biomass Pyrolysis Biomass thermochemical processes have been studied for at least two reasons: (1) a better understanding of the combustion process to control biomass flammability; and, (2) research into improved processes for converting biomass into useful energy forms. The late Fred Shafizadeh (see, e.g., 4,5) laid the groundwork for all recent studies in both arenas. The work on combustion mechanisms continues at the Wood Chemistry Laboratory of the University of Montana in Missoula (see, e.g., 6). Antal has recently (7,8) reviewed all aspects of biomass pyrolysis, and the reader is directed to his reviews for detail study of the processes involved. Chatterjee has produced an excellent summary (9) of biomass pyrolysis 0097-6156/88/0376-0001$06.00/0 ° 1988 American Chemical Society 2 PYROLYSIS OILS FROM BIOMASS rocesses relative to application in lesser developed countries. This author as also written several reviews on biomass thermochemical processes, and specifically pyrolysis (2,3,13). Several volumes have been published recently on thermal conversion (10,11), with another on the way for the 1988 Phoenix conference (12). The opening paragraph to this overview chapter relates the need for pyrolysis relative to liquid transportation fuels production. This is a rather specific energy need, and in fact, biomass can serve other energy needs as well. Charcoal from wood is the principal fuel of rural regions of most lesser developed countries. The gas from biomass gasification has found use in the retrofit of natural gas furnaces and engines, and highly efficient cogeneration plants. The energy content of residues from forestry and agricultural operations can often serve on-site process energy needs, but the biomass materials are generally poorly suited for direct use. Modern agricultural and process machinery seldom use solid fuels, therefore 1 0 pretreatments are often required to change their chemical or physical 0 ch nature to liquids or gases. Similar considerations apply to the conversion 76. of biomass crops and to the use of biomass fuels off-farm. Thermochemical 03 processes for biomass are basically pretreatment processes, processes that 88- alter the chemical and physical nature of biomass to permit higher 19 efficiency use. bk- Thermochemical processes are often characterized as combustion, 21/ gasification, pyrolysis, carbonization or tarification processes. Except for 0 1 pyrolysis, these names reflect types of products produced. Thermochemical 0. 1 processing is variable and flexible. Depending on conditions used, oi: (primarily the temperature, the oxygen-to-fuel ratio, and residence time at d 8 | temperature), biomass can be altered very slightly, or be completely 8 changed. These three variables define conditions for pyrolysis, gasification 9 1 and combustion but there is often little distinction between these processes. 30, In fact, there is a continuum of process conditions. Selection of treatment er conditions permits a variety of outcomes of importance to the production of b m bioenergy products. The mechanisms for the formation of these products e pt are indeed complex, and are still unfolding (see e.g., 7,8,14). Knowledge of e S these mechanisms has permitted the identification of conditions under ate: which it is possible to produce tars in good yield from large, moist wood D particles (15), or novel reactor design for the production and capture of n o desired tar products (16). Still, gases, liquids and solids are always ati produced, with relative yields and chemical or elemental compositions c bli dependent on process variables. u P Definition of Pyrolysis. The word pyrolysis has had some problems in definition, especially when applied to biomass. The older literature generally equates pyrolysis to carbonization, in which the principal pro duct is a solid char. Today, the term pyrolysis is generally used to describe processes in which liquid oils are preferred products. This symposium was concerned with the latter pyrolysis - processes which offer enhanced yields of liquid oils, especially those with desirable chemical compositions and physical attributes for liquid fuels, fuel supplements and chemical feedstocks. Definition of Pyrolysis Oil vs. Tar. Throughout this volume, "pyrolysis oil", "tar" and "pyrolytic tar" are used almost interchangeably. Tar or pyrolytic tar is a more generic term, now becoming used in reference to its formation in a secondary sense, e.g., as undesired in gasification, or the "creosote tar" of incomplete combustion or the usually