Table Of ContentCONTRIBUTORS
Richard J. Baltisberger
Zeinab Baset
Bradley C. Bockrath
John P. de Neufville
Howard Freund
Martin L. Gorbaty
Stephen C. Mraw
Kundan M. Patal
Janet R. Pullen
Krishna Raman
Virgil I. Stenberg
Neil F. Woolsey
Franklin J. Wright
Coal Science
V O L U ME 2
Edited by
MARTIN L. GORBATY
Corporate Research-Science Laboratories
Exxon Research and Engineering Company
Linden, New Jersey
JOHN W. LARSEN
Department of Chemistry
The University of Tennessee
Knoxville, Tennessee
IRVING WENDER
Chemical and Petroleum Engineering Department
The University of Pittsburgh
Pittsburgh, Pennsylvania
1983
ACADEMIC PRESS
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COPYRIGHT © 1983, BY ACADEMIC PRESS, INC.
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83 84 85 86 9 8 7 6 5 4 3 2 1
Contributors
Numbers in parentheses indicate the pages on which the authors' contributions begin.
Richard J. Baltisberger (125), Department of Chemistry, University of
North Dakota, Grand Forks, North Dakota 58202
Zeinab Baset1 (1), Exxon Research and Engineering Company, Linden,
New Jersey 07036
Bradley C. Bockrath (65), U.S. Department of Energy, Pittsburgh Energy
Technology Center, Pittsburgh, Pennsylvania 15236
John P. de Neufville2 (1), Exxon Research and Engineering Company,
Linden, New Jersey 07036
Howard Freund (1), Exxon Research and Engineering Company, Linden,
New Jersey 07036
Martin L. Gorbaty (1), Corporate Research-Science Laboratories, Exxon
Research and Engineering Company, Linden, New Jersey 07036
Stephen C. Mraw (1), Exxon Research and Engineering Company, Linden,
New Jersey 07036
Kundan M. Patal (125), Department of Chemistry, University of North
Dakota, Grand Forks, North Dakota 58202
Janet R. Pullen (173), IEA Coal Research, London SW1W 0EX, England
Krishna Raman (125), Department of Chemistry, University of North
Dakota, Grand Forks, North Dakota 58202
'Present address: Exxon Research and Engineering Co., Baytown, Texas 77520.
2Present address: Energy Conversion Devices, Inc., North Branch, New Jersey 08876.
vii
viii Contributors
Virgil I. Stenberg (125), Department of Chemistry, University of North
Dakota, Grand Forks, North Dakota 58202
Neil F. Woolsey (125), Department of Chemistry, University of North
Dakota, Grand Forks, North Dakota 58202
Franklin J. Wright (1), Exxon Research and Engineering Company, Linden,
New Jersey 07036
Preface
The ultimate need to replace liquid and gaseous fuels now derived from
petroleum and natural gas resources with synthetic fuels from coal is gen-
erally recognized. Although technological bases already exist for utilizing
coal directly in combustion and for converting it to liquid and gaseous
fuels, we feel that considerable improvements in these technologies (such
as greater overall thermal efficiency, hydrogen utilization, and selectivity
to specific products) are needed. These improvements, along with new,
more efficient routes to coal utilization, will only come about if we are
able to gain more fundamental knowledge of coal in terms of its structure
and reactivity.
Because coal is such a heterogeneous material, coal science in its broadest
sense embraces many scientific disciplines—including chemistry (organic,
inorganic, and physical), physics, and engineering (chemical and me-
chanical). Consequently, the literature of coal science is vast and complex,
containing a great deal of information—but only rarely in such a form that
this information is logically assembled, reviewed, and evaluated. Because
of the current interest in coal, we felt that critical reviews written by
experts and aimed at the professional chemist or engineer now working
(or contemplating working) in coal science would be both timely and useful.
These reviews would not only pull together what has been reported in
the past into a coherent picture, they would also point out the original
reports' significance as well as areas where more research is needed. Ul-
timately, coal science should furnish data and clues for solving or bypassing
many of the problems now associated with coal conversion technologies.
This is the second in a series devoted to presenting and evaluating se-
lected fundamental scientific areas involved with our understanding of
coal structure, reactivity, and utilization. Reviews describing current state-
of-the-art knowledge of coal's inorganic structure and reactivity and the
role ionic bonding plays in coal's chemical and physical structure and
reactivity are included, as well as contributions on hydrogen donor chem-
ix
X Preface
istry and solvent extraction, both relating to coal conversion and utili-
zation. It is our hope that this and subsequent volumes will not only be
a valuable source of information and a guide to the coal literature, but
will also stimulate research and serve as a basis for further advances in
science and technology.
The editors would like to thank the contributing authors for their time
and diligence in helping to make this volume a reality. We may have acted
as catalysts, but the major share of the credit belongs to them.
Contents of Volume 1
Coal Plasticity Mechanism: Inferences from Liquefaction Studies
Richard C. Neavel
The Physical Structure of Coal
Warren R. Grimes
Magnetic Resonance Studies of Coal
H. L. Retcofsky
Molecular Structure of Coal
Robert M. Davidson
The Reductive Alkylation Reaction
Leon M. Stock
Index
xi
The Science of Mineral Matter in Coal
STEPHEN C. MRAW, JOHN P. DE NEUFVILLE,*
HOWARD FREUND, ZEINAB BASET,| MARTIN L. GORBATY,
and FRANKLIN J. WRIGHT
Exxon Research and Engineering Company
Linden, New Jersey
I. Introduction 2
II. Mineral Matter in Coal: Origin, Characterization, and Implications
for Coal-Processing Technologies 3
A. Introduction 3
B. Origin of Mineral Matter in Coal and Resulting Mineralogical
and Chemical Variations 4
C. Identification and Characterization of Mineral Matter in Coal. 10
D. Role of Chemical Bonding of Inorganic Matter in Coal
Conversion or Combustion 24
III. Combustion 26
A. Introduction 26
B. Pulverized Coal Combustion Overview 27
C. Particulate Formation 29
D. Slagging 32
E. Fouling 36
F. Attempts to Combat Slagging and Fouling 37
G. Reduction of S0 Emissions via Ca-S Reactions 40
2
IV. Gasification and Liquefaction 42
A. Introduction 42
B. Sintered Deposits Formed in Gasification of Coal
Liquefaction Residues 42
C. Inorganic Components of Gaseous Streams 45
D. Catalytic Effects of Mineral Matter in Gasification 46
E. Catalytic Effects of Mineral Matter in Liquefaction 47
* Present address: Energy Conversion Devices, Inc., North Branch, New Jersey 08876.
t Present address: Exxon Research and Engineering Co., Baytown, Texas 77520.
1
COAL SCIENCE Copyright © 1983 by Academic Press, Inc.
Volume 2 All rights of reproduction in any form reserved.
ISBN 0-12-150702-5
2 Stephen C. Mraw et al.
V. Silicate Chemistry at Elevated Temperature and Its Relevance
to Ash Fusion Phenomena 49
A. Introduction 49
B. Sintering Phenomena—Combustion or Gasification of Coal
in a Bedded Unit: Relevance of ASTM Ash Fusion Test
(Initial Deformation Temperature) 50
C. Slagging Phenomena—Conventional Combustion of
Pulverized Coal in a Nonslagging Boiler: Relevance
of ASTM Ash Fusion Test to Actual Slagging Behavior 52
D. Summary Comparison of ASTM Test versus
Sintering and Slagging 57
References 59
I. INTRODUCTION
In this article we give a general overview of the area of mineral matter
in coal and a critical review of many specific aspects which are most in-
triguing scientifically. We consider the term mineral matter in its widest
sense, that is, all of the inorganic material found in coal as mineral phases
and the elements in coal that are considered inorganic (Gluskoter et al.,
1977). Such a broad area as mineral matter in coal would be extremely
difficult to review totally in all of its complex scientific and technological
aspects. It is our intent in this article to concentrate in detail on specific
portions of the total picture which are particularly intriguing to us on a
scientific basis, because complex and poorly understood chemical and
physicochemical mechanisms appear to be operating to produce the ob-
served results. Throughout the article, we shall often go beyond merely
reviewing the literature, in that we shall attempt to analyze the reported
results further and even speculate upon their significance, as a means of
indicating where further research is needed and would be most fruitful.
Our discussion of these questions will include mineral matter in what
can be thought of as "before, during, and after" processing, that is,
(1) The modes of introduction of mineral matter into coal and the
chemical and physical nature of the mineral matter in a present-day coal
(2) The effect of coal combustion or conversion on the mineral matter
and, conversely, the effect of the mineral matter on these high-temperature
processes
(3) The final chemical and physical state of the mineral matter or ash
after processing, and whether it is potentially hazardous or potentially
useful
In this vein we present, in Section II, a critical review of the modes of occur-
rence of inorganic elements in coal, both as mineral phases and as organ-
ically bonded elements, and we examine the effects that highly dispersed
