The biodiesel handbook PDF

Preview

Summary

Biodiesel FM(1-0)(Final)22 Nov 6/6/05 3:51 PM Page 1 The Biodiesel Handbook Editors Gerhard Knothe National Center for Agricultural Utilization Research Agricultural Research Service U.S. Department of Agriculture Peoria, Illinois, U.S.A. Jon Van Gerpen Department of Mechanical Engineering Iowa Stat...

Description

Accelerat ing t he world's research.

The biodiesel handbook Jignesh Mardania

Related papers

Download a PDF Pack of t he best relat ed papers 

Fuel Propert ies and Performance of Biodiesel Robert Dun, Sevim Erhan

Biodiesel Product ion and Propert ies mehmet t rakaniqi Fuel propert ies and nit rogen oxide emission levels of biodiesel produced from animal fat s Vict or Wyat t

The Biodiesel Handbook Editors Gerhard Knothe National Center for Agricultural Utilization Research Agricultural Research Service U.S. Department of Agriculture Peoria, Illinois, U.S.A.

Jon Van Gerpen Department of Mechanical Engineering Iowa State University Ames, Iowa, U.S.A.

Jürgen Krahl University of Applied Sciences Coburg, Germany

Champaign, Illinois

Copyright © 2005 AOCS Press

AOCS Mission Statement

To be the global forum for professionals interested in lipids and related materials through the exchange of ideas, information science, and technology. AOCS Books and Special Publications Committee M. Mossoba, Chairperson, U.S. Food and Drug Administration, College Park, Maryland R. Adlof, USDA, ARS, NCAUR, Peoria, Illinois P. Dutta, Swedish University of Agricultural Sciences, Uppsala, Sweden T. Foglia, ARS, USDA, ERRC, Wyndmoor, Pennsylvania V. Huang, Abbott Labs, Columbus, Ohio L. Johnson, Iowa State University, Ames, Iowa H. Knapp, Deanconess Billings Clinic, Billings, Montana D. Kodali, General Mills, Minneapolis, Minnesota T. McKeon, USDA, ARS, WRRC, Albany, California R. Moreau, USDA, ARS, ERRC, Wyndoor, Pennsylvania A. Sinclair, RMIT University, Melbourne, Victoria, Australia P. White, Iowa State University, Ames, Iowa R. Wilson, USDA, REE, ARS, NPS, CPPVS, Beltsville, Maryland Copyright (c) 2005 by AOCS Press. All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means without written permission of the publisher. The paper used in this book is acid-free and falls within the guidelines established to ensure permanence and durability.

Library of Congress Cataloging-in-Publication Data Biodiesel : etc / editor, Author. p. cm. Includes bibliographical references and index. ISBN 0-000000-00-00 (acid-free paper) 1. XXXX. 2. XXXXX. 3. XXXX. I. Author(s). TP991.S6884 2004 668'.12--dc22 2004008574 CIP Printed in the United States of America. 08 07 06 05 04 5 4 3 2 1

Copyright © 2005 AOCS Press

Preface

The technical concept of using vegetable oils or animal fats or even used oils as a renewable diesel fuel is a fascinating one. Biodiesel is now the form in which these oils and fats are being used as neat diesel fuel or in blends with petroleum-based diesel fuels. The concept itself may appear simple, but that appearance is deceiving since the use of biodiesel is fraught with numerous technical issues. Accordingly, many researchers around the world have dealt with these issues and in many cases devised unique solutions. This book is an attempt to summarize these issues, to explain how they have been dealt with, and to present data and technical information. Countless legislative and regulatory efforts around the world have helped pave the way toward the widespread application of the concept. This book addresses these issues also. To complete the picture, chapters on the history of vegetable oil-based diesel fuels, the basic concept of the diesel engine, and glycerol, a valuable byproduct of biodiesel production, are included. We hope that the reader may find the information in this book useful and stimulating and that most of the significant issues regarding biodiesel are adequately addressed. If a reader notices an error or inconsistency or has a suggestion to improve a possible future edition of this book, he or she is encouraged to contact us. This book has been compiled from the contributions of many authors, who graciously agreed to do so. We express our deepest appreciation to all of them. We also sincerely thank the staff of AOCS Press for their professionalism and cooperation in bringing the book to print. Gerhard Knothe Jon Van Gerpen J ü rgen Krahl November 4, 2004

Copyright © 2005 AOCS Press

Contributing Authors

Gerhard Knothe, USDA, ARS, NCAUR, Peoria, IL 61604 Jon Van Gerpen, Department of Mechanical Engineering, Iowa State University, Ames, IA 50011 Michael J. Haas, USDA, ARS, ERRC, Wyndmoor, PA 19038 Thomas A. Foglia, USDA, ARS, ERRC, Wyndmoor, PA 19038 Robert O. Dunn, USDA, ARS, NCAUR, Peoria, IL 61604 Heinrich Prankl, BLT–Federal Institute of Agricultural Engineering, A 3250 Wieselburg, Austria Leon Schumacher, Department of Biological Engineering, University of MissouriColumbia, Columbia, MO 65211 C.L. Peterson, Department of Biological and Agricultural Engineering (Emeritus), University of Idaho, Moscow, ID 83844 Gregory Möller, Department of Food Science and Technology, University of Idaho, Moscow, ID 83844 Neil A. Bringe, Monsanto Corporation, St. Louis, MO 63167 Robert L. McCormick, National Renewable Energy Laboratory, Golden, CO 80401 Teresa L. Alleman, National Renewable Energy Laboratory, Golden, CO 80401 Jürgen Krahl, University of Applied Sciences, Coburg, Germany Axel Munack, Institute of Technology and Biosystems Engineering, Federal Agricultural Research Center, Braunschweig, Germany Olaf Schröder, Institute of Technology and Biosystems Engineering, Federal Agricultural Research Center, Braunschweig, Germany Hendrik Stein, Institute of Technology and Biosystems Engineering, Federal Agricultural Research Center, Braunschweig, Germany Jürgen Bünger, Center of Occupational and Social Medicine, University of Göttingen, Göttingen, Germany Steve Howell, MARC-IV Consulting Incorporated, Kearney, MO 64060 Joe Jobe, National Biodiesel Board, Jefferson City, MO 65101 Dieter Bockey, Union for Promoting Oilseed and Protein Plants, 10117 Berlin, Germany

Copyright © 2005 AOCS Press

Jürgen Fischer, ADM/Ölmühle Hamburg, Hamburg, Germany Werner Körbitz, Austrian Biofuels Institute, Vienna, Austria Sven O. Gärtner, IFEU-Institute for Energy and Environmental Research, Heidelberg, Germany Guido A. Reinhardt, IFEU-Institute for Energy and Environmental Research, Heidelberg, Germany Donald B. Appleby, Procter & Gamble Chemicals, Cincinnati, OH 45241

Copyright © 2005 AOCS Press

Contents

Preface Contributing Authors

1

Introduction Gerhard Knothe

2

The History of Vegetable Oil-Based Diesel Fuels Gerhard Knothe

3

The Basics of Diesel Engines and Diesel Fuels Jon Van Gerpen

4

Biodiesel Production

4.1

Basics of the Transesterification Reaction Jon Van Gerpen and Gerhard Knothe

4.2

Alternate Feedstocks and Technologies for Biodiesel Production Michael J. Haas and Thomas A. Foglia

5

Analytical Methods for Biodiesel Gerhard Knothe

6

Fuel Properties Gerhard Knothe

6.1

Cetane Numbers–Heat of Combustion–Why Vegetable Oils and Their Derivatives Are Suitable as a Diesel Fuel Gerhard Knothe

6.2

Viscosity of Biodiesel Gerhard Knothe

6.3

Cold Weather Properties and Performance of Biodiesel Robert O. Dunn

6.4

Oxidative Stability of Biodiesel

6.4.1 Literature Overview Gerhard Knothe

Copyright © 2005 AOCS Press

6.4.2 Stability of Biodiesel Heinrich Prankl 6.5

Biodiesel Lubricity Leon Schumacher

6.6

Biodiesel Fuels: Biodegradability, Biological and Chemical Oxygen Demand, and Toxicity C.L. Peterson and Gregory Möller

6.7

Soybean Oil Composition for Biodiesel Neal A. Bringe

7

Exhaust Emissions

7.1

Effect of Biodiesel Fuel on Pollutant Emissions from Diesel Engines Robert L. McCormick and Teresa L. Alleman

7.2

Influence of Biodiesel and Different Petrodiesel Fuels on Exhaust Emissions and Health Effects Jürgen Krahl, Axel Munack, Olaf Schröder, Hendrik Stein, and Jürgen Bünger

8

Current Status of the Biodiesel Industry

8.1

Current Status of Biodiesel in the United States Steve Howell and Joe Jobe

8.2

Current Status of Biodiesel in the European Union Dieter Bockey

8.2.1 Biodiesel Quality Management: The AGQM Story Jürgen Fischer 8.3

Status of Biodiesel in Asia, the Americas, Australia, and South Africa Werner Körbitz

8.4

Environmental Implications of Biodiesel (Life-Cycle Assessment) Sven O. Gärtner and Guido A. Reinhardt

8.5

Potential Production of Biodiesel Charles L. Peterson

9

Other Uses of Biodiesel Gerhard Knothe

10

Other Alternative Diesel Fuels from Vegetable Oils Robert O. Dunn

Copyright © 2005 AOCS Press

11

Glycerol Donald B. Appleby Appendix A: Technical Tables Appendix B: Biodiesel Standards Appendix C: Internet Resources

Copyright © 2005 AOCS Press

1

Introduction Gerhard Knothe

Introduction: What Is Biodiesel? The major components of vegetable oils and animal fats are triacylglycerols (TAG; often also called triglycerides). Chemically, TAG are esters of fatty acids (FA) with glycerol (1,2,3-propanetriol; glycerol is often also called glycerine; see Chapter 11). The TAG of vegetable oils and animal fats typically contain several different FA. Thus, different FA can be attached to one glycerol backbone. The different FA that are contained in the TAG comprise the FA profile (or FA composition) of the vegetable oil or animal fat. Because different FA have different physical and chemical properties, the FA profile is probably the most important parameter influencing the corresponding properties of a vegetable oil or animal fat. To obtain biodiesel, the vegetable oil or animal fat is subjected to a chemical reaction termed transesterification.In that reaction, the vegetable oil or animal fat is reacted in the presence of a catalyst (usually a base) with an alcohol (usually methanol) to give the corresponding alkyl esters (or for methanol, the methyl esters) of the FA mixture that is found in the parent vegetable oil or animal fat. Figure 1 depicts the transesterification reaction. Biodiesel can be produced from a great variety of feedstocks. These feedstocks include most common vegetable oils (e.g., soybean, cottonseed, palm, peanut, rapeseed/canola, sunflower, safflower, coconut) and animal fats (usually tallow) as well as waste oils (e.g., used frying oils). The choice of feedstock depends largely on geography. Depending on the origin and quality of the feedstock, changes to the production process may be necessary. Biodiesel is miscible with petrodiesel in all ratios. In many countries, this has led to the use of blends of biodiesel with petrodiesel instead of neat biodiesel. It is important to note that these blends with petrodiesel are not biodiesel. Often blends with petrodiesel are denoted by acronyms such as B20, which indicates a blend of 20% biodiesel with petrodiesel. Of course, the untransesterified vegetable oils and animal fats should also not be called “biodiesel.” Methanol is used as the alcohol for producing biodiesel because it is the least expensive alcohol, although other alcohols such as ethanol or i s o-propanol may yield a biodiesel fuel with better fuel properties. Often the resulting products are also called fatty acid methyl esters (FAME) instead of biodiesel. Although other alcohols can by definition yield biodiesel, many now existing standards are designed in such a fashion that only methyl esters can be used as biodiesel if the standards are observed correctly.

Copyright © 2005 AOCS Press

Fig. 1. The transesterification reaction. R is a mixture of various fatty acid chains. The alcohol used for producing biodiesel is usually methanol (R′ = CH3).

Biodiesel has several distinct advantages compared with petrodiesel in addition to being fully competitive with petrodiesel in most technical aspects: • Derivation from a renewable domestic resource, thus reducing dependence on and preserving petroleum. • Biodegradability. • Reduction of most exhaust emissions (with the exception of nitrogen oxides, NOx). • Higher flash point, leading to safer handling and storage. • Excellent lubricity, a fact that is steadily gaining importance with the advent of low-sulfur petrodiesel fuels, which have greatly reduced lubricity. Adding biodiesel at low levels (1–2%) restores the lubricity. Some problems associated with biodiesel are its inherent higher price, which in many countries is offset by legislative and regulatory incentives or subsidies in the form of reduced excise taxes, slightly increased NOx exhaust emissions (as mentioned above), stability when exposed to air (oxidative stability), and cold flow properties that are especially relevant in North America. The higher price can also be (partially) offset by the use of less expensive feedstocks, which has sparked interest in materials such as waste oils (e.g., used frying oils). Why Are Vegetable Oils and Animal Fats Transesterified to Alkyl Esters (Biodiesel)? The major reason that vegetable oils and animal fats are transesterified to alkyl esters (biodiesel) is that the kinematic viscosity of the biodiesel is much closer to

Copyright © 2005 AOCS Press

that of petrodiesel. The high viscosity of untransesterified oils and fats leads to operational problems in the diesel engine such as deposits on various engine parts. Although there are engines and burners that can use untransesterified oils, the vast majority of engines require the lower-viscosity fuel. Why Can Vegetable Oils and Animal Fats and Their Derivatives Be Used as (Alternative) Diesel Fuel? The fact that vegetable oils, animal fats, and their derivatives such as alkyl esters are suitable as diesel fuel demonstrates that there must be some similarity to petrodiesel fuel or at least to some of its components. The fuel property that best shows this suitability is called the cetane number (see Chapter 6.1). In addition to ignition quality as expressed by the cetane scale, several other properties are important for determining the suitability of biodiesel as a fuel. Heat of combustion, pour point, cloud point, (kinematic) viscosity, oxidative stability, and lubricity are among the most important of these properties.

Copyright © 2005 AOCS Press

2

The History of Vegetable Oil-Based Diesel Fuels Gerhard Knothe

Rudolf Diesel It is generally known that vegetable oils and animal fats were investigated as diesel fuels well before the energy crises of the 1970s and early 1980s sparked renewed interest in alternative fuels. It is also known that Rudolf Diesel (1858–1913), the inventor of the engine that bears his name, had some interest in these fuels. However, the early history of vegetable oil-based diesel fuels is often presented inconsistently, and “facts” that are not compatible with Diesel’s own statements are encountered frequently. Therefore, it is appropriate to begin this history with the words of Diesel himself in his book Die Entstehung des Dieselmotors (1) [The Development (or Creation or Rise or Coming) of the Diesel Engine] in which he describes when the first seed of developing what was to become the diesel engine was planted in his mind. In the first chapter of the book entitled “The Idea,” Diesel states: “When my highly respected teacher, Professor Linde, explained to his listeners during the lecture on thermodynamics in 1878 at the Polytechnikum in Munich (note: now the Technical University of Munich) that the steam engine only converts 6–10% of the available heat content of the fuel into work, when he explained Carnot’s theorem and elaborated that during the isothermal change of state of a gas all transferred heat is converted into work, I wrote in the margin of my notebook: ‘Study, if it isn’t possible to practically realize the isotherm!’ At that time I challenged myself! That was not yet an invention, not even the idea for it. From then on, the desire to realize the ideal Carnot process determined my existence. I left the school, joined the practical side, had to achieve my standing in life. The thought constantly pursued me.” This statement by Diesel clearly shows that he approached the development of the diesel engine from a thermodynamic point of view. The objective was to develop an efficient engine. The relatively common assertion made today that Diesel developed “his” engine specifically to use vegetable oils as fuel is therefore incorrect. In a later chapter of his book entitled “Liquid Fuels,” Diesel addresses the use of vegetable oils as a fuel: “For [the] sake of completeness it needs to be mentioned that already in the year 1900 plant oils were used successfully in a diesel engine. During the Paris Exposition in 1900, a small diesel engine was operated on arachide (peanut) oil by the French Otto Company. It worked so well that only a few insiders knew about this inconspicuous circumstance. The engine was built for petroleum and was used for the plant oil without any change. In this case also, the consumption experiments resulted in heat utilization identical to petroleum.” A total of five diesel engines

Copyright © 2005 AOCS Press

were shown at the Paris Exposition, according to a biography (2) of Diesel by his son, Eugen Diesel, and one of them was apparently operating on peanut oil. The statements in Diesel’s book can be compared to a relatively frequently cited source on the initial use of vegetable oils, a biography entitled Rudolf Diesel, Pioneer of the Age of Power (3). In this biography, the statement is made that “as the nineteenth century ended, it was obvious that the fate and scope of the internal-combustion engine were dependent on its fuel or fuels. At the Paris Exposition of 1900, a Diesel engine, built by the French Otto Company, ran wholly on peanut oil. Apparently none of the onlookers was aware of this. The engine, built especially for that type of fuel, operated exactly like those powered by other oils.” Unfortunately, the bibliography for the corresponding chapter in the biography by Nitske and Wilson (3) does not clarify where the authors obtained this information nor does it list references to the writings by Diesel discussed here. Thus, according to Nitske and Wilson, the peanut oil-powered diesel engine at the 1900 World’s Fair in Paris was built specifically to use that fuel, which is not consistent with the statements in Diesel’s book (1) and the literature cited below. Furthermore, the above texts from the biography (3) and Diesel’s book (1) imply that it was not Diesel who conducted the demonstration and that he was not the source of the idea of using vegetable oils as fuel. According to Diesel, the idea for using peanut oil appears to have originated instead within the French government (see text below). However, Diesel conducted related tests in later years and appeared supportive of the concept. A Chemical Abstracts search yielded references to other papers by Diesel in which he reflected in greater detail on that event in 1900. Two references (4,5) relate to a presentation Diesel made to the Institution of Mechanical Engineers (of Great Britain) in March 1912. (Apparently in the last few years of his life, Diesel spent considerable time traveling to give presentations, according to the biography by Nitske and Wilson.) Diesel states in these papers (4,5) that “at the Paris Exhibition in 1900 there was shown by the Otto Company a small Diesel engine, which, at the request of the French Government, ran on Arachide (earth-nut or pea-nut) oil, and worked so smoothly that only very few people were aware of it. The engine was constructed for using mineral oil, and was then worke...