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Vol. 12, No. 1, 2001
ENERGY - Perception Versus Reality
Burt Davis
UK Center for Applied Energy Research
Part II of a two part series.
In the 1970s, direct liquefaction of coal to
produce transportation fuels was
considered a certainty. The United States
had two major demonstration plants
(200-600 tons coal/day) and two somewhat smaller ones operating. Other large
demonstration plants were operating in
several countries. Kentucky, with its large
production of coal, was to be the Saudi
Arabia of the Western nations. In 1980,
petroleum was projected to cost more
than $100/barrel by the year 2000. Thus,
the projected cost of petroleum was
greater than even the most pessimistic
estimate for the cost of production of
synthetic fuels. With time the projected
price of petroleum substitute declined but
has always been above the actual cost, at
least until the mid 1980s.
During the past 15
years, the cost of
crude has varied but it has remained in
the $10-30/barrel range. The cost of
petroleum had remained nearly constant
for so long that when it reached $10/
barrel, and even lower, nearly all experts
could explain why crude would remain
around this price for several years.
Within a year the price had exceeded $30/
barrel and U.S. government officials were
scrambling to find a “solution” to this
crisis that resulted in gas pump prices
becoming high enough to shock customers into action.
Oil shale retorting was a commercial
certainty in the 1970s. Even Eastern U.S.
shale, which required fluid-bed pyrolysis,
was considered likely with U.S. and
foreign companies scrambling to develop
large-track leases for the Kentucky
resources. The CAER progressed from a
1 inch to a 2 inch to a larger 6 inch fluidbed pilot plant. At the time of completion
of the 6 inch plant, Exxon announced
that they were abandoning the commercial development of oil shale. Federal and
State support for this effort vanished.
Today there are few options that are
considered to be less likely than oil shale.
Tar sands have made some in-roads and
a commercial operation continues in
Canada; however, the economic
viability of this depends on the
person that is talking.
Biomass conversion has been
practiced at a small scale for
many years. In 1980, one
study projected that biomass
would provide almost 10%
or the total energy
consumed in the U.S. by
the year 2000; another
more optimistic study
expected that 19% of
the total energy
consumed in 2000
would come from
biomass. At that time,
the limitations of
extensive development of biomass
resources were considered to be its high
land and water requirements and the
competition with food production.
However, the limitation was and continues to be economic - the cost of production is greater than the value of the
(continued, page 2)
Effective
Utilization of
Coal-derived
Phenolic
Chemicals
Chunshan Song and Harold H. Schobert
The Pennsylvania State University
INTRODUCTION
This article provides an overview for
potential utilization of coal-derived
phenolic compounds. Phenolic compounds are abundant in coal-derived
liquids. Coal-derived phenolic compounds include phenol, cresol, catechol,
methylcatechol, naphthol, and their
derivatives. Liquids from coal liquefaction, pyrolysis, gasification, and carbonization are potential sources of phenolic
chemicals, although certain processing
and separation is needed. There are
opportunities for coal-based phenolic
chemicals, because industrial applications
and potential new applications exist.
Currently the petrochemical industry
produces phenol in multi-step processes.
Selective methylation of phenol can
produce a precursor for aromatic
engineering plastics. Catalytic oxidation
of phenol has been commercialized
recently for catechol production. There
are potential new uses of phenol that
could replace large-volume multi-step
(continued, page 3)
Energy - Perception Versus Reality, (cont.)
(A)
( A ) Conventional use of premium fuels for
process and agriculture.
(B ) Premium fuel use restricted to farming
machinery.
(B)
Figure 12. Flows in energy units (Applied Catalysis).
energy produced - and the net energy
balance. The latter point, net energy
balance, is illustrated in Figure 12. Both
options are based on production of
premium fuel by agriculture. In one
instance corn is converted to fuel grade
ethanol, and the net energy balance is
negative (-4.0%). A positive net energy
balance results in this case only if
biomass residue and coal are utilized in
the production of the premium fuel.
Nevertheless, the U.S. has continued to
produce and utilize ethanol in its
premium transportation fuels, and
thereby contributes to its energy shortage.
It has been estimated that in 1992, the
production of chickens in the Southeastern U.S. produced 5 million tons of waste
(J. A. Jones and A. C. Sheth, Proc.
Renewable Adv. Energy system, 21 st
Century, 1999, 78-90). In the past much
of this was used as fertilizer. Jones and
Sheth propose that this waste be gasified
to produce energy. If this is done, what
impact would it have on our energy
picture? Assuming an optimistically high
carbon content of 40% and a 100%
efficiency in gasification and conversion
of the carbon to liquid fuels, the 5 million
tons of chicken waste could produce
43,500 barrels/day transportation fuel.
Since the U.S. consumes about 18 million
barrels/day, this would provide 0.24% of
the country’s consumption. A more
optimistic approach has been proposed
by President Clinton. This would
mandate that by 2010, 7.5% of U.S.
electricity be produced using “renewable
energy resources.” The goal of this is
obviously environmentally driven. One
view of this action is that this is
“...scarcely more realistic than mandating ‘repeal’ of a law of physics...”(M.
McCormack, C&E News, Sept. 13, 1999,
p. 3) to the view that “All it would take
to stimulate the generation of 7.5% of
our electricity and more from renewable
sources is a crude oil price that remains
above $25 per barrel.”(D. L. Klass,
President, Biomass Energy Research,
C&E News, Nov. 15, 1999, p. 6).
Unfortunately, many of these well
meaning laws end up having a result
that is contradictory to what was
intended. For example, as a result of the
OPEC-created crisis in the 1970s,
congress created a “synfuels bill” that
was to provide a $25/ton tax write-off for
each ton of coal recovered from holding
ponds and similar sources. However,
with time the effort has changed so that
today synfuels are generated by adding
2-3% petroleum product to newly mined
coal, and then selling the synfuel for less
than the real market value of newly
mined coal. In short, it is difficult to
provide a subsidy that is not easily
circumvented.
U.S. refineries are being shed by the
major oil companies because the margin
for refining is far too low to satisfy Wall
2
Street’s expectations. Today, refineries
operate at 95+% capacity. Unless some
action is taken that leads to increased
refinery capacity or to importation of
finished products rather than crude,
the U.S. will continue to face higher
prices based on real shortages of
refined products. The nation’s last
energy policy was formulated during
President Carter’s years and, intentionally or otherwise, petroleum companies
have worked for 20 years to undo it.
Petroleum companies are merging and
shedding their refineries to become
downstream marketers of high-profit
products. At the present trend, the U.S.
shall return soon to the 1880’s when
John D. Rockefellor’s Standard Oil
was the only petroleum company.
Based on historical reality, there is no
reason to be upset about today’s pump
price for transportation fuel. The
change in supply is completely inadequate to cause a price change at the
pump of 50%, either as an increase or a
decrease. However, both have occurred
during the past three years. Human
nature dictates that one does not
complain when the change is in one’s
favor, – but to complain loudly when
the change goes against one. A historical view allows us to conclude that the
price fluctuations during the past five
years have been perception based.
Will the future be based on perception
or reality? One thing seems certain: the
U.S. does not have an energy policy and
there is little reason to believe that one
will be developed during the shortterm. Today, the U.S. Department of
Energy (DOE) is responsible for
developing a policy; however, the
legislative and executive branches seem
to be more concerned with eliminating
rather than working with that department. This has led to DOE looking
more and more at short-term actions.
Petroleum producers and refiners who
used to consider short-term to be a
matter of years, now look no further
than the next quarter’s profit. Companies, either because of perception or
reality, feel compelled to meet the
expectations of Wall Street and to show
ever expanding profits. In this setting,
companies cannot develop long-term
plans, let alone help formulate longterm energy policies. During the past 30
years, at least, the U.S. energy policy
has been one of benign neglect that
reacts only to sudden changes, and
only if viewed negatively by the public,
with actions that provide the perception of action.
(continued, page 3)
Energy - Perception Versus Reality, (cont.)
Effective Utilization (cont.)
The shock caused by the petroleum
shortfall of the 1970s aroused the public
to the extent that the U.S. developed an
energy policy. Unfortunately, it was
produced over a short period and was
based on limited data that was extrapolated far beyond the region where it was
valid. An examination of the literature
indicates that for about three years (19721975) the effort of scientists and engineers
was to “relearn” the work that had been
done during the previous crisis. With
very limited data, the decision to build
large demonstration plants was made
and there was an “expensive crash
program” to get the plants built and
running. At the same time, funds were
made available to assist with commercial
plants. The Reagan administration
rapidly shut-down this activity when it
assumed office. In the relaxed atmosphere of the 1980s, any thoughts of
developing a real energy policy for the
U.S. were forgotten, and this attitude
chemical processes that are based on
benzene as the starting material. New
chemical research on coal and coalderived liquids can pave the way for their
non-fuel uses for making chemicals and
materials.
remains today. Any attention to an energy
policy is driven by environmental
concerns and with making larger and
larger suburban recreational vehicles that
utilize more and more fuel for each mile
that is traveled. Some countries do
appear to be trying to formulate an
energy policy but, unfortunately, many of
these appear to be based more on
idealized environmental considerations
than on workable energy efficiency
considerations. Hopefully, the U.S. will
not let the current jump in petroleum
prices pass without beginning the process
of developing a rational energy policy.
Dr. Davis has long worked in the energy
arena. He has been at the CAER since
1977 and currently serves as interim
director. He may be contacted at
[email protected].
PHENOLIC COMPOUNDS
FROM PETROLEUM AND
COAL
Phenol is one of the major industrial
organic chemicals, and ranked among the
top twenty in the U.S. (by the amount
produced). Table 1 shows the development of phenol production in the U.S.,
Western Europe, and Japan from 1985
to1995. It is currently produced mainly
from a multi-step process starting from
benzene, as described below. Benzene is
separated from BTX fraction extracted
from catalytically reformed naphtha or
pyrolysis gasoline. The purified benzene
is converted to cumene
(isopropylbenzene) by catalytic
isopropylation over an acidic catalyst.
Subsequently, cumene is converted to
cumene hydroperoxide, which produces
(continued, page 4)
3
Effective Utilization, (cont.)
COUNTRY
PHENOL
SOURCE
US
Synthetic phenol
1260
1553
1873
From tar and
wastewater
24
27
27
Total
1284
1580
1900
1985 1991 1995
They can be separated directly
from the coal liquids by liquidphase extraction, and can be used
as-is or converted into monomers
such as bisphenol A and 2,6dimethylphenol for making
aromatic polymers and engineering plastics.
form a mixture of cyclohexanol and
cyclohexanone. Cyclohexnol in the mixture
is isolated and then dehydrogenated to
produce cyclohexanone. Cyclohexane is
produced from benzene hydrogenation. A
second route to cyclohexanone is through
phenol hydrogenation. In 1990 about 63 %
of the worldwide caprolactam production
was based on cyclohexane oxidation and
the remainder came from the phenol
hydrogenation route and other routes.
One could argue that the market
of phenol is relatively small and if
there is one large commercial plant
From tar and
14
28
14
wastewater
for coal liquefaction, the phenol
An earlier phenol route involves a two-step
from such a plant could saturate
process, ring hydrogenation to
Total
the current market. The pessimiscyclohexanol over a nickel catalyst and
tic view may take this considerthen dehydrogenation over a Zn or Cu
ation
as
a
stop
sign
for
further
catalyst to cyclohexanone. Some of the
Japan
Synthetic phenol
255
568
771
progress in phenol utilization.
catalysts developed for commercial
However, proactive measures can
operation of cyclohexanol dehydrogenation
From tar and
2
2
N/a
wastewater
open up new opportunities and
to cyclohexanone are Cu/MgO and Cu/
new applications. If phenol can be
ZnO catalysts containing alkali promoter.
Total
257
570
771
produced in larger quantities,
However, recent research using some noble
other applications of phenol may
metal-based catalysts has made it possible
Sources: (a) Weissermel, K. and H.-J. Arpe, 1997; (b) C&EN, Facts & Figures,
June 24, 1996.
become attractive in addition to its
to convert phenol to cyclohexanone in one
current uses, which may also
step. For example, some recent results by
Table 1. Phenol production in the U.S.,
become competitive to some other
Srinivas Srimat in our laboratory show
Western Europe and Japan (in metric tons).
industrial manufacturing prothat high selectivity to cyclohexanone can
cesses that currently do not use phenol.
be obtained in a single step under the
phenol and acetone upon acid-catalyzed
conditions of phenol hydrogenation over
cleavage. Until 1990 about 97 % of the total
supported noble-metal catalysts modified
synthetic phenol in the U.S., over
INDUSTRIAL USES OF
in specific ways.
90 % in Western Europe, and 100 % in
PHENOL
Japan was manufactured by this process.
The world capacity for phenol using the
Table 2 shows the worldcumene process is currently about five
wide industrial uses of
WESTERN
PRODUCT
WORLD
US
JAPAN
phenol. The current
million tons per year. In 1990-1991 a new
EUROPE
process based on toluene was introduced,
industrial uses of phenol
1989 1995 1985 1995 1986 1994 1985 1994
include the production of
and this route is now used for about 91 %
of phenol production in Western Europe.
phenolic resins (Bakelite,
Novolacs), bisphenol A,
Phenol is still the largest-volume chemical
Total (million tons) 4.70 5.23 1.07 1.79 0.25 0.50 1.05 1.25
derived from benzene, and its production
caprolactam, alkylphenols,
and adipic acid, as well as
currently consumes about 20 % of the total
Distn (%)
benzene production. In addition to
some other uses, as shown
in Table 2. Bisphenol A,
synthesis, phenol is also produced in
Phenolresins
36
37
40
30
36
33
41
29
smaller quantities from tar and coke-oven
also known as 2,2-bis-(4hydroxyphenyl)propene
water from coal coking and low temperaCaprolactam
7
15
18
17
17
16
ture carbonization of low-rank coals.
produced from condensation of phenol and acetone,
Phenols, cresols and xylenols can be
Bisphenol A
20
32
22
35
29
39
22
27
recovered by washing coal-derived liquid
is widely used in the
manufacture of synthetic
with alkaline solutions and treating the acid
Adipic acid
1
2
1
1
1
2
solution with CO 2.
resins and thermoplastics,
such as polycarbonates
Alkylphenols
5
2
4
6
4
4
4
6
(Figure 1).
By carefully designing the reactions, we can
convert coals into liquids that are rich in
12
15
11
26
24
24
20
For example, caprolactam is Miscellaneous (1) 21
aromatic and phenolic compounds, which
an important industrial
are valuable chemical feedstocks. Phenol
(1) e.g., aniline, chlorophenols, plasticizers, antioxidants. Sources: (a) Weissermel, K. and
organic chemical, with a
can be directly separated from liquids
H.-J. Arpe, 1997; (b) C&EN, Facts & Figures, June 24, 1996.
worldwide production
produced from coals through pyrolysis,
Table 2. Industrial Uses of Phenol in the World, US,
capacity of 3.44 million tons
carbonization, hydropyrolysis or liquefacWestern Europe and Japan (in 1000 metric tons).
in 1989 (with 0.96, 0.60,
tion. It has been shown that phenolic
and 0.51 million tons per
compounds are dominant components in
Cresols and xylenols can be obtained
year in Western Europe, U.S., and Japan,
the products from pyrolysis of low-rank
from coal liquids or from methylation of
respectively). It is used for the manufaccoals, as demonstrated by flash pyrolysisphenol. The demand for o-cresol and 2,6ture of Nylon 6. It is synthesized also
GC-MS of several subbituminous coals.
xylenol has increased recently, so that the
from a multi-step process with cyclohexAnalysis of products from coal liquefaction
demand can no longer be met solely from
anone as the key intermediate. Most
also indicated this trend. Phenols can be
petroleum and coal tar sources. o-Cresol
cyclohexanone is made from cyclohexane,
extracted from coal-derived liquids by
is favored in methylation of phenol at
produced from cyclohexane oxidation to
traditional or non-traditional methods.
Western Europe
Synthetic phenol
1157
1460
1493
4
(continued, page 5)
Effective Utilization, (cont.)
Potential new markets for phenol,
including coal-derived phenols, can be
developed by exploring more environmentally benign syntheses that use phenol,
which can replace existing routes that
involve more corrosive acids or toxic
agents. Several examples are given below.
Figure 1. Synthesis of polycarbonate by phosgene-free
route via trans-esterification of bisphenol A
with diphenyl carbonate.
300-360 °C under 40-70 bar over an
alumina catalyst; at higher temperatures and pressures, 2,6-xylenol is
favored. 2,6-Xylenol is the starting
material for polyphenylene oxide
(Figure 2), a thermoplastic developed
by General Electric, which has high
heat and chemical resistance and
excellent electrical properties.
developed and is being commercialized by
Solutia Co.
Catechol is a useful industrial chemical, and
can be synthesized from hydroxylation of
phenol. Notari and coworkers have developed
a new process for hydroxylation of phenol to
produce catechol over microporous crystalline
titanium silicates catalysts. Such a reaction can
also be promoted by other catalysts such as VZr-O complex oxide. On the other hand,
One option in the coal chemicals
catechol is present in relatively high concentracommunity may be to wait and let
tions in liquids derived from
pyrolysis of low-rank coals. Some
catechol derivatives are valuable
chemicals. For example, veratrole
(ortho-dimethoxybenzene) is an
important chemical for the production of alkaloids and pharmaceuticals. Veratrole can be synthesized in
Figure 2. Synthesis of polyphenylene
the vapor phase using catechol and
oxide via methylation of phenol,
dimethyl carbonate over alumina
and condensation of 2,6-xylenol.
loaded with potassium nitrate.
others take the first step (and also the
risk). However, the result may be a
further shift in market away from
coal-based chemicals. For example,
while some researchers on coal
chemicals still think the market for
phenol is too small for coal-based
chemicals, several new processes have
been developed in petrochemicals and
chemical industries. As a result, an
earlier cumene process using Lewis
acidic AlCl3 catalyst was replaced by
new processes using a solid acid
catalyst such as Al 2O3-supported
phosphoric acid. A recent development
in the 1990s is another new cumene
process commercialized by Dow
Chemical Company, which uses
chemically modified mordenite as a
catalyst for benzene isopropylation.
Most recently, a new type of process
based on direct oxidation of benzene
with nitrogen oxide to produce phenol
over molecular sieve catalyst was
POSSIBLE NEW USES OF
PHENOL
New Oxygenates for Gasoline. One possible use
is to make oxygenated compounds as an
alternative to current fuel additives such as
methyl-tert-butyl ether (MTBE). The use of
MTBE for reformulated gasoline is under
increasing pressure from environmentalists for
its possible health and environmental effects.
As an alternative, methylcyclohexyl ether
(MCHE) may be a potential oxygenate
additive for liquid fuels. Phenol can be
hydrogenated to cyclohexanol and its condensation reaction with methanol can produce
methylcyclohexyl ether (MCHE). Phenol can
be selectively hydrogenated into cyclohexanol
over certain catalysts. Methanol is a largervolume commodity chemical, and can also be
obtained from coal gasification followed by
synthesis from syngas over Cu-Zn type
catalysts.
New Environmentally-Benign Manufacturing.
5
The phosgene-free synthesis of organic
carbonate is an important research area
because phosgene currently used for
making some industrial organic chemicals
is toxic. Diphenyl carbonate is an essential
starting material for phosgene-free
synthesis of an important engineering
plastic material, polycarbonate resin, as
shown in Figure 1. Direct synthesis of
diphenyl carbonate can be carried out
using phenol. For example, oxidative
carbonylation of phenol can be carried
out using carbon monoxide and air over a
Pd-Cu based catalyst to produce diphenyl
carbonate.
Aniline is an important industrial organic
chemical. In 1993 the production of
aniline was 537, 508, and 184 thousand
tons in the Western Europe, US, and
Japan, respectively. Aniline is currently
synthesized by a multi-step process:
nitration of benzene, followed by hydrogenation of nitrobenzene. Direct synthesis
of aniline from phenol and ammonia can
be carried out using MFI-type molecular
sieve catalysts. For example, galliumcontaining an MFI type catalyst has been
found to be effective for the aniline
synthesis from phenol.
SUMMARY
Utilization of phenol will be an important
part of non-fuel uses of coal and coalderived liquids in the future. Current
routes of industrial uses of phenol include
the production of phenolic resins,
bisphenol A, caprolactam, alkylphenols,
adipic acid, antioxidants, aniline,
plasticizers, and chlorophenols. The
demand for phenol has increased
significantly in the past two decades and
this trend is expected to continue. There
are existing and new opportunities for
developing and using phenol and phenol
derivatives in chemical process industries.
Drs. Song and Schobert lead an active
research group on clean fuels, chemicals
and catalysis research in the Energy
Institute, and they are faculty members in
the Department of Energy & Geo-Environmental Engineering, The Pennsylvania
State University. Dr. Song may be reached
at: [email protected].
ANNOUNCING APPOINTMENT OF NEW
CAER DIRECTOR
Arie Geertsema was recently
approved by the University of
Kentucky Board of Trustees as
the new director of the Center for
Applied Energy Research.
“The university is gratified to
have such an internationally
recognized fuel scientist and
industrialist as the new leader of
UK’s Center for Applied Energy
Research and as a faculty member
of the College of Engineering,”
said Fitzgerald B. Bramwell, vice president for Research and
Graduate Studies. “Dr. Geertsema’s expertise will position CAER
and UK to respond aggressively to the research needs of a
changing and dynamic industry for both the producers and users
of Kentucky coal.”
Geertsema, who most recently served as gas processing manager
at the Commonwealth Science and Industrial Research Organization in Australia, has more than 30 years of experience in indus-
trial chemistry, chemical engineering, plant operations, and
research and development. He served as managing director
of the internationally recognized Sastech Research and
Development Division of Sasol for 10 years. Sasol, one of the
biggest coal producers in the world and leader in coal
conversion, processing and utilization technologies, processes
more than 40 percent of South Africa’s liquid fuel requirements.
Geertsema received a Ph.D. in chemical engineering from the
University of Karlsruhe in Germany in 1976 and an M.B.A.
from the University of Potchefstroom in South Africa.
His recent professional awards include the 1994 Industrial
Chemistry Medal from the South African Institute of
Chemistry for promoting industrial chemistry and university-industry interactions and the 1993 Stokes Award from
the International Pittsburgh Coal Conference for leadership
in commercialization of coal conversion technologies.
Geertsema will also hold an associate professor position in
the UK College of Engineering Department of Chemical and
Materials Engineering.
Energeia is published six times a year by the University of Kentucky's Center for Applied Energy Research (CAER). The publication features aspects of energy resource
development and environmentally related topics. Subscriptions are free and may be requested as follows: Marybeth McAlister, Editor of Energeia, CAER, 2540 Research
Park Drive, University of Kentucky, Lexington, KY 40511-8410, (859) 257-0224, FAX: (859)-257-0220, e-mail: [email protected]. Current and recent past issues
of Energeia may be viewed on the CAER Web Page at www.caer.uky.edu. Copyright © 2001, University of Kentucky.
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