EPA-600/R-96-003
January 1996
The Carnol Process for C02 Mitigation
from Power Plants and the Transportation Sector
by
Meyer Steinberg
Department of Advanced Technology
Brookhaven National Laboratory
Upton, NY 11973
EPA Interagency Agreement DW89936346
EPA Project Officer: Robert H. Borgwardt
National Risk Management Research Laboratory
Research Triangle Park, NC 27711
Prepared for:
U.S. Environmental Protection Agency
Office of Research and Development
Washington, DC 20460

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TECHNICAL REPORT DATA ... „ ............... . ......
(Please read Instructions on the reverse before complete || | |||| j ||||| III II 1 1II
1, REPORT NO. 2.
EPA-600/R~ 96-003
3. r 111 mi 11 mil 11111 iii 111111111
PB96-14 5065
^fieLb^rnofTi^"rocess for CO2 Mitigation from Power
Plants and the Transportation Sector
5. REPORT DATE
January 1996
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Meyer Steinberg
8. PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U. S. Department of Energy
Brookhaven National Laboratory
Upton, New York 11973
10, PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO,
IAG DW89936346
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Air Pollution Prevention and Control Division
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final; 3/94 - 8/95
14. SPONSORING AGENCY CODE
EPA/600/13
15. supplementary notes APPCD project officer is Robert H. Borgwardt, Mail Drop 63,
919/541-2336.
16.abstract The report describes an alternative mitigation process that would convert
waste carbon dioxide (C02) to carbon and methanol using natural gas as process feed-
stock, The process yields 1 mole of methanol from each mole of C02 recovered, re-
sulting in a net zero CC2 emission when the methanol is used as transportation fuel
to displace petroleum. Further C02 can be mitigated by sequestering the carbon by-
product. A computer simulation of the process was used to perform materials and
energy balances. Preliminary economics of the process are evaluated. Two process
modifications are identified that could lead to further improvements. The application
of C02 mitigation technologies such as this depends on how seriously the country and
the world consider the global warming problem since they would involve massive cap-
ital investments and fundamental changes in energy use problems. (NOTE*. Among the
options for mitigation of greenhouse gas emissions and the effects of global climate
change is the removal, recovery, and sequestration of C02 from central power plants
that primarily burn coal. Various technologies for accomplishing that strategy are
under investigation elsewhere. Carbon is much less difficult to sequester than C02.)
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI FieM/Gioup
Pollution Carbinols
Carbon Dioxide Carbon
Electric Power Plants
Coal
Combustion
Tr ansportation
Pollution Control
Stationary Sources
Methanol
13 B 07C
07B
10 B
21D
21B
15E
18. distribution statement
Release to Public
19. SECURITY CLASS {ThisReport}
Unclassified
21. NO. OF PAGES
27
20. security class (Thispage)
Unclassified
22. PRICE
EPA Form 2220 1 (9 73)

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NOTICE
This document has been reviewed in accordance with
U.S. Environmental Protection Agency policy and
approved for publication. Mention of trade names
or commercial products does not constitute endorse-
ment or recommendation for use.
ii

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FOREWORD
The U.S. Environmental Protection Agency is charged by Congress with pro-
tecting the Nation's land, air, and water resources. "Under a mandate of national
environmental laws, the Agency strives to formulate and implement actions lead-
ing to a compatible balance between human activities and the ability of natural
systems to support and nurture life. To meet this mandate, EPA's research
program is providing data and technical support for solving environmental pro-
blems today and building a science knowledge base necessary to manage our eco-
logical resources wisely, understand how pollutants affect our health, and pre-
vent or reduce environmental risks in the future.
The National Risk Management Research Laboratory is the Agency's center for
investigation of technological and management approaches for reducing risks
from threats to human health and the environment. The focus of the Laboratory1 s
research program is on methods for the prevention and control of pollution to air,
land, water, and subsurface resources; protection of water quality in public water
systems; remediation of contaminated sites and groundwater; and prevention and
control of indoor air pollution. The goal of this research effort is to catalyze
development and implementation of innovative, cost-effective environmental
technologies; develop scientific and engineering information needed by EPA to
support regulatory and policy decisions; and provide technical support and infor-
mation transfer to ensure effective implementation of environmental regulations
and strategies.
This publication has been produced as part of the Laboratory's strategic long-
term research plan. It is published and made available by EPA's Office of Re-
search and Development to assist the user community and to link researchers
with their clients.
E. Timothy Oppelt, Director
National Risk Management Research Laboratory
i i i

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Abstract
A carbon dioxide (C02) mitigation process is developed which converts waste C02,
primarily from coal-fired power plant stack gases, to methanol for use as a liquid fuel and a
coproduct carbon for use as a materials commodity. The Carnol process chemistry consists of
methane decomposition to produce hydrogen which is catalytically reacted with the recovered
waste C02 to produce methanol. The carbon is either stored or sold. A process design is
modelled, and mass and energy balances are presented as a function of reactor pressure and
temperature conditions. The Carnol process is a viable alternative to sequestering C02 in the
ocean for purposes of reducing CO, emissions from coal burning power plants. Over 90% of the
CO2 from the coal burning plant is used in the process which results in a net CO, emission
reduction of over 90% compared to that obtained for conventional methanol production by steam
reforming of methane. Methanol, as an alternative liquid fuel for automotive engines and for
fuel cells, achieves additional C02 emission reduction benefits. The economics of the process is
greatly enhanced when carbon can be sold as a materials commodity. The process design and
economics could possibly be achieved by developing a molten metal (tin) methane
decomposition reactor and a liquid phase, slurry catalyst, methanol synthesis reactor directly
using the solvent saturated with C02 scrubbed from the power plant stack gases. The application
of C02 mitigation technologies, such as the Carnol process, depends to some extent, on how
serious the country and the world takes the global greenhouse gas warming problem since such
an approach would involve massive capital investments and fundamental changes in the country's
energy use patterns.
iv

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Table of Contents
Abstract 									 i v
List of Tables	 vi
List of Figures 			 vi i
Metric Conversion Factors			 vi i i
I Introduction	.,					1
I! The Carnol. Process Description	1
III	Carnol Process Design							 3
IV	Preliminary Economic Analysis 		4
V	Advanced Carnol VI Process					6
VI	Conclusion									8
References 			8
Tables			10
Figures			15
v

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List of Tables
Table 1 - Simplified Thermodynamic Analysis of Carnol Process	10
Table 2 - Methanol Production Efficiency and C02 Emission Reduction as a Function of Process
Reactor Conditions					11
Table 3 - Carnol Process HI Design - Process Simulation-Mass and Energy Balances ...... 12
Table 4 - Preliminary Carnol Process Economics	13
Table 5 - Methanol Synthesis Equilibrium Starting with 1 Mole C02 and 3 Moles H2	14
vi

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List of Figures
Figure 1 - Simplified Carnol Process for Producing Methanol from Natural Gas and Waste C02
for Zero C02 Emission	,15
Figure 2 - Equilibrium Data for Methane Decomposition, CH4 = C + 2H2 				16
Figure 3 - Process Flowsheet - Carnol Process III						17
Figure 4 - C02 - H20 Amine Phase Equilibrium .......					18
Figure 5 - Camol VI Process for C02 Mitigation Technology - Combining C02 Recovery from
Power Plants with Liquid Metal Methane Decomposition and Liquid Phase Methanol
Synthesis 					19
Figure 6 - Molten Metal Methane Decomposition Reactor for Carnol VI Process Design .... 20
vi i

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List of Metric Conversion Factors
Nonmetric
Times
Yields Metric
atm
101,325
Pa
bbl
159
1
Btu
1,054
J
cal
4,184
J
gal
3,785
1
lb
0.4536
kg
MSCF
28,320
std m3
ton
0,9072
tonne
viii

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L INTRODUCTION
The evidence for greenhouse gas C02 warming causing global climate change is
continuing to mount, and international agreements are being sought to Emit CO, emissions(I),
The C02 emissions are primarily due to fossil fuel combustion (principally coal, oil, and gas) in
the industrial, commercial, and transportation sectors. Although much effort in the U.S. has gone
into the science of climate change, relatively little effort has been expended for technologies that
mitigate greenhouse gas emissions. Improvement in efficiency of energy production and
utilization is recognized as a cost effective method for reducing C02 emission to a limited
degree®. Fuel substitution, utilizing more natural gas and oil versus coal, is recognized to
further reduce C02 emission. The use of biomass for energy production is also effective in C02
reduction. A more aggressive manner for reducing C02 emissions is the removal, recovery, and
then disposal of C02 from central power plants, which primarily burn coal. A fair amount of
research has gone into disposal and sequestering of C02 in the ocean and in depleted gas wells(3).
However, C02 sequestration presents some formidable, technical, and economic problems.
Much less effort has gone into precombustion fuel processing to significantly reduce C02
emission. Coal gasification combined cycle is one limited step in that direction but still requires
C02 sequestration(3). The concept of extraction and disposal of carbon from fossil fuels and
utilization of the hydrogen enriched fractions has been introduced with the idea that carbon is
much less difficult to store and sequester than C02<4 '. The coprocessing of fossil fuels with
biomass by the Hydrocarb process*5', producing methanol as a liquefied fuel, can achieve zero
C02 emission. The use of methanol as an efficient automotive fuel can further reduce C02
emission from the transportation sectoral To maximize methanol production and reduce
development effort, the Hynol process which coprocesses biomass with natural gas has been
introduced(7) and avoids carbon sequestration while still obtaining significant C02, emission
reduction in a cost effective manner. In this paper we describe and develop an alternative
process which converts waste C02, primarily recovered from coal-fired power plant stack gases,
using natural gas to produce methanol as a liquid fuel and carbon as a storable materials
commodity coproduct.
II. THE CARNOL PROCESS DESCRIPTION
The Carnol process grew out of a preliminary investigation of alternative processes for
using C02(S). The Carnol process relies on two basic chemical reactions; the thermal
decomposition of methane and the catalytic synthesis of methanol from hydrogen with C02
Methane decomposition: 3CHa = 3C + 6H-,
Methanol synthesis:	2C02 + 6H2 = 2CH3OH + 2H20
Overall process:	3CII4 + 2C02 = 2CH3OH +211,0 + 3C
Thus 1 mole of methanol is produced from the utilization of 1 mole of C02 which results
in a net zero C02 emission when the methanol is burned. It takes 1.5 moles of CH4 to produce 1
mole of methanol or to react with 1 mole of C02 by means of hydrogen. The C02 mitigation
1

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comes about by removing 1 mole of C02 from power plant stack gas (primarily coal fired) and
producing but not burning the 1.5 moles of carbon per mole of methanol produced.
Both reactions are known to take place and have been practiced in different forms on a
commercial scale. Methane decomposition to form carbon black is known as the Thermal Black
process1'0. The hydrogen is not recovered in this process but is used as fuel. From an energy
point of view the Thermal Black process as commercially practiced is very inefficient. A
continuous catalytic methane cracking process called Hypro has been operated for hydrogen
production for hydrocracking oil in a refinery; however, in this case the carbon was not
recovered but was used as fuel in the process"01.
The catalytic methanol synthesis from CO, and hydrogen has also been practiced
commercially; however, only on a limited scale, mainly because of the lack of cost effective C02
feedstock'1'I Most methanol produced currently is made by the catalytic synthesis of CO and
hydrogen which is produced bv the steam reforming of natural gas'121. There is no reduction in
CO> emission by the use of the conventional methanol synthesis process using natural gas. In
fact when coal is used to produce the synthesis gas, there is a large increase in C02 emission.
The Camol process development is based on the following considerations.
1.	Much chemical engineering development effort has recently gone into removal and
recovery of CO, from power plant stack gases. Through the use of hindered amine
absorption solvents, the energy requirement for C02 removal and recovery has been
significantly reduced131.
2.	In principle, hydrogen production by methane decomposition requires the least amount of
energy compared to other means of hydrogen production, such as steam reforming of
methane and electrolysis of water(l4). It only takes 18 kcaf to decompose 1 mole of
methane. Thus the production of 1 mole of hydrogen requires only 5% of the energy of
combustion of natural gas. The kinetics of methane decomposition has been further
studied"31 and has become better understood. High surface area carbon itself can act as
an autocatalyst for improving rates of decomposition at lower temperatures..
3.	Much catalyst development work has lately gone into the synthesis of methanol from C02
and hydrogen resulting in the development of improved catalysts(16).
4.	Methanol as an alternative fuel has a number of benefits: (1) it is a liquid fuel which can
be used on a large scale, (2) it can be transported and stored in accordance with the
present infrastructure, (3) it can be used in stationary and automotive engines as a
substitute for petroleum based fuel, thus reducing imports and improving the balance of
payments, (4) when used in internal combustion engines, it is 30% more efficient than
gasoline which results in lower C02 emission"" in the transportation sector, and (5) it has
Readers more familiar with metric units may use the factors listed at the end of the
front matter of this report to convert to this system.
2

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potential as an ideal fuel supply for efficient fuel cell power systems now under
development.
5.	The Carnol process converts C02 from power plant stacks to another useful fuel product
and thus the carbon from the power plant is essentially used twice. Furthermore, the
methanol fuel can obtain additional C02 reduction when used in the dispersed automotive
sector of the economy. CO > emission from automotive engines emits about 30% of the
total emission of C02 in the U.S. which is about the same quantity of CC)2 emitted from
central power plant stacks.
6.	it is possible to obtain low net C02 emission without the use of biomass. Instead of using
waste C02 from the atmosphere through biomass, Carnol uses waste C02 directly from
coal burning power plant stacks.
7.	It is possible to consider the large scale application of Carnol because next to coal, natural
gas is abundantly available at low cost.
Based on thermodynamic principles, a first order simplified analysis of Carnol can be
made using the simplified two reactor flow diagram shown in Figure 1 and given in Table 1(8).
Hydrogen is used to provide the endothermic heat of reaction (by indirect heat transfer) for the
thermal decomposition of methane so as to obtain zero C02 emission. The catalytic CO-/H-,
reaction for methanol synthesis is exothermic and can produce some process steam. Table 1
indicates that there is a 61% reduction in methanol yield by the Carnol process compared to the
conventional methanol process by steam reforming of methane using the same simplified
procedure. However, the CO, emission is completely eliminated compared to conventional
methanol production. Although the thermal efficiency is 49.7% compared to 81.5%(i2) by the
conventional process, there is available a significant quantity of carbon coproduct which can be
sold as a useful material on the commodity market to offset methanol costs in competing with
conventional methanol cost. Because the potential production of carbon from the process can
exceed the current market for carbon, new markets for carbon can be made available as an
alternative to just sequestering (storage) of the carbon. Thus, thermal efficiency is not the only
criterion by which to judge the Carnol process.
III. CARNOL PROCESS DESIGN
A process design and analysis has been made taking into account process temperature and
pressure conditions. A computer simulation program was used to make a detailed mass and
energy balance. The assumptions in the model are:
1.	Close approach to equilibrium is assumed in the methane decomposition reactor (MDR)
and the methanol synthesis reactor (MSR). The equilibrium data for methane
decomposition are graphically shown in Figure 2.
2.	A fluidized bed MDR is assumed using an indirectly heated circulating alumina heat
transport system. The rate of methane thermal decomposition is adequate, for a
reasonable reactor design, at temperatures of 800°C and above(15).
3

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3.	The MSR is a conventional Imperial Chemical Industries, Inc. (ICI) type gas-phase
methanol catalytic converter operating at 50 atm pressure and 260°C with a 4 to 1 recycle
ratio to achieve close to 100% conversion of the C02 feed to the MSR system.
4.	A multistage compressor increases the pressure of the process gas from the MDR to the
MSR. The compressor is driven by steam generated from the MDR combustor exhaust
gas.
5.	A condenser-fractionator separates the product methanol from the water, and the
exothermic energy from the MSR provides the steam for the fractionator,
6.	Residual gas from the MSR is recycled to the MDR for either process gas or as fuel in the
combustor.
7.	C02 is supplied as gas at 1 atm from the power plant stack: gas recovery system.
A number of recycled and heat transfer configurations and process variables were
explored. Table 2 gives the results of 11 computer runs for the process flow sheet configuration
shown in Figure 3 (designated as Carnol III) varying the MDR pressure and temperature from I
to 50 atm and the temperature from 800 to 1100°C respectively. Increasing temperature in the
MDR decreases C02 emission, and increasing pressure in the MDR increases C02 emission.
Decreasing pressure in the MSR also increases C02 emission. Table 2 indicates that, at I atm
pressure in the MDR and temperatures from 800 to 1100°C, the yield (thermal efficiency) of
MeOH remains at 41.1% while the C02 emission is reduced by 87% and higher compared to the
combustion of methanol produced by the conventional steam reforming process. From a materials
point of view, temperatures on the order of 800 to 900°C for the MDR are preferable. The flow
sheet of Figure 3 is based on an MDR temperature of 800°C. A summary of the mass and energy
balances for Carnol III is given in Table 3 and the stream compositions in Figure 3. The decrease
in thermal efficiency from the simplified analysis of 49.7% indicates the inefficiencies when taking
into account detailed mass and energy balances.
The C02 feed to the Carnol process is provided by removal and recovery from coal fired
power plant stack gases by a monoethanolamine (MEA) solvent absorption-stripping system. The
amine system has been used for C02 removal and recovery from process gases in ammonia and
methanol plants in the U.S. for a number of decades. Recently published papers from Japan(!3)
have shown that hindered amine solvents and improved absorption column packing can decrease
the pressure drop across the column. That system, with the power plant, has decreased energy
requirements so that there is only an 8% loss in power from a coal burning plant when recovering
90% or better of the C02 from its stack gases.
IV. PRELIMINARY ECONOMIC ANALYSIS
The assumptions made are:
1. C02 is removed and recovered from a 600 MW(e) coal burning plant (40% efficiency)
using amine solvent at 90% C02 recovery, 90% plant factor, and 10% additional capacity
to make up for avoidance loss.
4

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MMBtu coal
x 6x 105 kW(e) x
8500Btu
kW(e)
2000lb
= 4.34 x 106 Tlyr
The Carnol plant capacities are shown at the bottom of Table 4 requires 400,000 MSCF/D
of natural gas. The methanol production rate is 8460 T/D or 61,100 bbl/D and the carbon
produced is 5800 T/D.
2.	Since, the Camol plant has two reaction steps (MDR and MSR) and the conventional
plant has two steps (steam reforming of methane and MeOH synthesis), the capital
investment is based on an equivalent conventional methanol world size plant estimated at
$100,000/ton MeOH/day(17), Thus, the total investment is $100,000 x 8460 T/D =
$846x10*. Production cost is estimated based on factors of capital investment as follows:
19% for financing (depreciation & interest), 1% for labor, 3% for maintenance and 2% for
power and miscellaneous, resulting in a total of 25% of the capital investment on an
annual basis for the production cost.
3.	Natural gas prices are assumed to vary between $2 and S3/MSCF ($95 to $142/ton).
Note that natural gas prices in the U.S. were as low as $1,50/MSCF ($71/ton) in 1994.
4.	The carbon is assumed to be stored at SlO/ton. Carbon can also result in income since it
has a market in tires, pigments, newsprint inks, etc. Depending on grade, carbon can sell
for from $100 to $1000/ton. In Table 4, carbon price balanced production cost at less
than $20/ton.
5.	The cost of C02 to Carnol recovered from the power plant can be a highly variable
quantity depending on whether there is a carbon tax, in which case Carnol can charge the
power plant for disposing of the C02. At foil cost recovery, it is estimated that $5/ton
would cover the cost of CO, recovery, assuming 8% reduction in power plant output
charged at $0.06/kWh(e). Other C02 cost charges were also assumed varying from zero
to $108/ton as the market income of MeOH varied.
6.	The market price of MeOH has been historically around $0.45/gal (S136/ton) depending
on stable natural gas feed stock costs. Recently, the MeOH market price increased to
$1.30 gal ($394/ton) due to a supply shortage in its use for production of methyltertiary
butyl ether (MTBE) mandated as a gasoline oxygenation agentll8). This huge increase in
price has a profound effect on the economics of the Carnol process. However, as soon as
new MeOH capacity comes on line in the next several years, it is expected that the price
will drop back to historical levels<18). At $0.45/gal MeOH competes with gasoline at a
production cost of $0.69/gal based on a 30% improvement in internal combustion (IC)
engine efficiency (1.54 gal MeOH is equivalent to 1 gal gasoline)<6). No credit is taken in
this paper for the use of methanol as a transportation fuel which would result in an
additional 30% reduction in C02 emission compared to gasoline.
In Table 4, production cost factors were equated to income factors and the C02 credit was
determined in the last column and evaluated as the figure of merit for the process. The
conclusions drawn from this analysis are:
5

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1.	When operating the MDR at 900°C and above and the MSR at 50 aim, the CO, emission
reduction is greater than 90% compared to C02 emission for methanol production by the
conventional process.
2.	With no cost for feedstock C02 to Carnol, natural gas at S2/MSCF, no credit for carbon,
and methanol at $0.45/gallon. the cost of reducing C02 emission is $25/ton (listed as
negative credit). This is less than the average International Energy Agency (IEA)
estimate for removal, recovery and sequestering C02 in the ocean at $37/ton neglecting
transportation (pipelining) costs to the ocean. At S3/MSCF the C02 reduction cost using
Camol increases to $55/ton which is the upper limit for ocean disposal of CO, neglecting
pipelining to the ocean.
3.	By selling the carbon as a commodity at $58 and $126/ton when natural gas costs $2 and
S3/MSCF respectively, the C02 reduction cost is reduced to zero. Since the carbon is
very pure this carbon price of $0.06/lb or less would have an easy market to compete with
current prices of carbon black of up to S0.50/lb. The U.S. market for tire carbon amounts
to 2 x 10® tons/yr. and there are other uses for carbon at a low cost price, for example as a
filler in construction materials.
4.	If the power plant wants to recover its cost for recovering C02 up to as high as $10/ton, at
a natural gas cost of S3/MSCF, carbon produced by Carnol would have to sell for
$ 170/ton ($Q.085/lb) to achieve zero C02 reduction cost, which is still a very reasonable
possibility.
5.	If the methanol can continue to demand $1.30/gal or almost 3 times the historical price, at
S3/MSCF for natural gas and C02 feedstock cost recovered from the power plant of
$5/ton (recoverable cost) and assuming no carbon sales, a CO, credit of $103/ton for
reducing C02 emission can be realized. On the other hand, if the C02 credit for reducing
emissions is reduced to zero, the power plant could charge as much as $ 108/ton for
feeding its CO, to the Carnol plant. Obviously the charges and profits could be
negotiated between the power plant and the Carnol plant.
It can be pointed out that the production of carbon using all the C02 from a 600 MW(e)
coal fired power plant for feedstock to the Carnol plant will produce approximately 2 x
10" T/Yr of carbon black which is equivalent to the current market capacity of the carbon
black. Thus, new markets for carbon black must be developed—if a cost offset to
methanol is needed-as an alternative to just sequestering the carbon. At a low cost of
carbon, as offered by the Camol process, a new market should be possible, for example,
for carbon as a filler in construction material.
V. ADVANCED CARNOL VI PROCESS
Two recent developments have been uncovered that could significantly improve the basic
Carnol process. One is methane decomposition and the other is methanol synthesis.
1. The design of an efficient methane decomposition reactor (MDR) can be difficult because
high temperature energy must be provided to decompose the methane, and the particulate
carbon must be recovered and removed in a continuous manner. As mentioned earlier,
6

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intermittent reheat batch reactors and fluidized bed reactors have their drawbacks.
Recently, we have found that molten metal technology is being applied to decompose
liquid and solid carbonaceous waste material to produce simple gaseous compounds
using a molten iron (Fe) bath at temperatures from 1400 to 1650°C(19). The advantage of
using a molten metal bath to decompose waste material can be readily applied to the
decomposition of methane. Molten metal is a good liquid phase direct contact heat
transfer media through which gaseous methane can be bubbled. The large density
differences between solid carbon and the molten metal could allow efficient capture from
the gas phase and separation of the carbon particles from the liquid phase by flotation.
Although molten iron at temperatures up to 1600°C could completely decompose
methane to its elements, carbon and hydrogen, as indicated by the equilibrium diagram in
Figure 2, the use of such extreme temperatures is a disadvantage when it becomes
necessary to design a thermally efficient heat recovery system. Molten tin (Sn) at a lower
temperature appears to be a suitable molten metal media for an MDR for the following
reasons:
a)	The liquid range for Sn is much wider than for Fe; Mpt - 236°C to Bpt 2260°C.
b)	Density of liquid Sn = 7.31 g/cm3
c)	Partial pressure of Sn at 1000°C = < 10"6 atm (< 1 ppm)
d)	Molten tin in the range of 800 to 1000°C should be sufficient to decompose
methane to a high degree.
e)	The molten metal Sn bath may also be catalytic for decomposing methane.
f)	Carbon does not react or dissolve in liquid Sn.
g)	Surface nitrided refractory metal (titanium or molybdenum) can provide adequate
corrosion resistant materials for heat transfer and containment of the molten tin.
h)	The viscosity of the molten Sn is low which provides for good mixing between the
gaseous and liquid phases.
2. Recently liquid-phase catalytic synthesis of methanol has been shown to improve
production of methanol because of improvement in transferring the exothermic heat of
the synthesis reaction'201. The catalyst is in a slurry form in an organic solvent carrier
such as an oil or glycol. For application in the Carnol process it then becomes possible to
practice liquid-phase methanol synthesis by reacting hydrogen with C02 when it becomes
absorbed in the MEA solvent during recovery from the power plant stack gases. A
methanol synthesis catalyst would be carried in slurry form in the MEA absorbent. The
conditions for the synthesis can be estimated from the phase diagram shown in Figure 4
using a hindered amine solvent03'. For example, absorbing flue gas C02 from a coal
burning plant, at equilibrium at 40°C, produces a solution having a C02 to amine ratio of
0.58. Heating this solution to 120°C gives an equilibrium partial pressure of CO , above
this solution of 100 psia (6,8 atm). By pressurizing this solution with hydrogen up to
about 30 atm pressure, thus providing a 3 to 1 H? to C02 partial pressure ratio in the
presence of the slurry catalyst, methanol should be formed. Table 5 estimates the
equilibrium concentration of methanol at 30 and 50 atm and at 120 and 260°C,
respectively, when feeding a 3 to 1 ratio of H2 to C02 mixture. These data indicate a
7

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much improved yield of methanol at the lower temperature, which results in a lower
recycle ratio and improved economics of the process120.
Applying the above two developments, a Carnol VI process flowsheet is designed
and is shown in Figure 5. The heat recovery around the molten tin reactor and the
separation of hydrogen from the unreacted methane by pressure swing adsorption (PSA)
to produce a pure H2 stream are shown in Figure 6. A heat and mass balance for Carnol
VI indicates that the overall thermal efficiency for production of methanol is 49.7%, By
storing the carbon or using it as a materials commodity, the net C02 emission, taking
credit for C02 from the power plant, is 13.0 kgC02/GJ (30.2 lb C02/MMBtu) which
represents an 83% reduction in C02 emission compared to the production of methanol by
conventional process; i.e., the steam reforming of natural gas. When methanol is used in
IC engines an additional 30% reduction in C02 emission is obtained compared to the use
of gasoline as automotive fuel.
VI. CONCLUSION
The Carnol process, which produces methanol as a liquid fuel, can effectuate a very
significant net decrease in C02 emission from coal-fired power plants. The economic value is
significantly improved when the coproduct carbon can be sold as a materials commodity. Two
research and development efforts which can significantly improve the process are (1) developing a
molten metal methane decomposition reactor and (2) developing a liquid-phase MEA slurry
catalyst reactor for directly converting C02 scrubbed from power plant fuel gas with hydrogen
from methane decomposition to produce methanol as a liquid fuel for the automotive industry.
Further development of the Carnol process is required to realize the full benefits of the process.
Serious consideration of the applicability of the Carnol process depends on how serious the
country and the world takes the global greenhouse gas warming problem and C02 mitigation
technologies.
REFERENCES
[1]	W.K. Stevens, "Scientists Warn of Effect of Rise in Greenhouse Gases," New York
Times, The Environment, p.C4 (April 11, 1995).
[2]	E. Mills, D, Wilson, T. Johanssen, "Getting Started. No Regrets Strategies for Reducing
Greenhouse Gas Emissions," Energy Policy, July/August (1991),
[3]	U.S. Department of Energy, "The Capture, Utilization and Disposal of C02 from Fossil
Fuel-Fired Power Plants," Vols, I and II, Washington, D.C. (1993),
[4]	M. Steinberg, "Biomass and Hydrocarb Technology for Removal of Atmospheric C02,"
BNL-44410, Brookhaven National Laboratory, Upton, NY (March 1990).
[5]	M. Steinberg, Y. Dong , R.H. Borgwardt," The Coprocessing of Fossil Fuels and
Biomass for C02 Emission Reduction in the Transportation Sector," Energy Convers.
Mgmt. 34, No, 9-11, p. 1015-1022 (1993).
8

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[6]	EPA Report, "An Analysis of the Economic and Environmental Effects of Methanol as an
Automotive Fuel," EPA Report No. 0730, (NTIS PB90-225806), Motor Vehicle
Emissions Laboratory, Ann Arbor, Michigan (September, 1989).
[7]	M. Steinberg, Y. Dong, "Hynol, an Economic Process for Methanol Production from
Biomass and Natural Gas with Reduced C02 Emission," BNL-49733, Brookhaven
National Laboratory, Upton, NY (October 1993).
[8]	M. Steinberg, Y. Dong, "The Camol Process for Methanol Production and Utilization
with Reduced C02 Emissions," BNL-60575, Brookhaven National Laboratory, Upton,
NY (June 1994).
[9]	J.P. Donnet, A. Voet, Carbon Black, pp. 16-18, Marcel Dekker, New York, NY (1976).
[10]	"Hypro Process Cleaves Hydrogen from Hydrocarbon," Chem. Eng. 69, p. 90-91 (1962).
[11]	Faith, Keyes, Clarke, Industrial Chemicals 4th Edition, p.526, John Wiley and Sons, New
York, NY (1975).
[12]	L.E. Wade et al., "Methanol," Kirk-Othmer Encyclopedia of Chemical Technology 15.
3rd Ed., p. 398-415, Wiley-Interscience and Sons, New York, NY (1981).
[13]	Suda et al., "Development of Fuel Gas Carbon Dioxide Recovery Technology," Chapter in
Carbon Dioxide Chemistry: Environmental Issues. Ed. by Jon Paul and Claire-Marie
Pradier, p. 222-35, The Royal Society of Chemistry, Sweden (1994).
[14]	M. Steinberg, "The Hy-C Process (Thermal Decomposition of Natural Gas) Potentially
the Lowest Cost Source of Hydrogen with the Least CO, Emission," BNL-61364,
Brookhaven National Laboratory, Upton, NY (December 1994).
[15]	A. Kobayashi, M. Steinberg, "The Thermal Decomposition of Methane," BNL-47159,
Brookhaven National Laboratory, Upton, NY (January 1992).
[16]	H. Arakawa et al., "Effective Conversion of C02 to Methanol and Dimethyl Ether by
Catalytic Hydrogenation Over Heterogeneous Catalysts," International Conference on
Carbon Dioxide Utilization, p. 95-102, University of Bari, Italy (Sept. 26-30, 1993).
[17]	J. Korchnak, John Brown Co. A/E Houston, TX, Personal Communication (1994).
[18]	(j. Peaff, Methanol Transformation to Commodity Status Stretchers Supply, Chem. &
Eng. News, p. 13-15 (October 24, 1994),
[19]	P. Nahass, P. A. Moise, C.A. Chanenchuk, "Quantum CEP for Mixed Waste Processing,"
Molten Metal Technology, Inc., Waltham, MA (1994).
[20]	S. Lee, Methanol Synthesis Technology, p. 198-224, CRC Press, Inc., Boca Raton, FL
(1990).
[21]	S. Okyama, "Evaluation of Low Temperature Methanol Synthesis in the Liquid Phase,"
ACS Division of Fuel Chemistry, 200th ACS National Meeting 39 No. 4, p. 1182-6,
Washington, D.C. (Aug. 20-25, 1994).

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Table 1
SIMPLIFIED THERMODYNAMIC ANALYSIS OF CARNOL PROCESS
Unit Operations
Reaction
Enthalpy, AH
Decomposition:
MeOH Synthesis:
3CIL = 3 C i 61L
2CO, + 6H, = 2CH,OH + 2H,0
+ 18 kcal/mol CIL
22 kcal/mol MeOH
Combustion:
h2 + m = h2o
68 kcal/mol H,
Carnol Process Analysis
Moles CH4 to produce 2 moles MeOH
Moles CH4 to produce combustion H2 for heat transfer to CH4
Moles MeOH per total mole CH4
Higher heat of combustion of MeOH
Higher heat of combustion of CII4
Carnol MeOH thermal efficiency
Carbon produced per mol MeOH
= 2.00/3.455
3.455/2.0
3.000
= 0.455
= 0.579
= 182,000 kcal/Mol
= 212,000 kcal/Mol
= 49.7%
1.728
C02 emission=~2 mol C02 (from stack gas) +2 mol C02 from MeOH combustion - 0
Conventional Process Analvsis(12)
Moles MeOH produced per mol CH4
Thermal efficiency
Moles CO produced per mol CH4
Relative to Conventional Methanol
Carnol process C02 reduction
Yield of Camol MeOH to conventional
0.95
: 81.5%
= 1.05
= 100%
61%
10

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Table 2
METHANOL PRODUCTION EFFICIENCY AND C02 EMISSION REDUCTION
AS A FUNCTION OF PROCESS REACTOR CONDITIONS
CARNOLIII+ PROCESS CONFIGURATION FOR
METHANOL PRODUCTION FROM C02 AND METHANE
Methane Feed = 100 kg
Computer
Run No.
MDR
P atm/T°C
MSR
P atm/T°C
co2
Feed
Stock
kg
MeOH
Thermal
Eff.
%
MeOH
Carbon
Eff.
%
co2
Emission
lb
MM Btu
HHV MeOH
C02*
Emission
Reduction
1
1/800
50/260
156.6
41.1
50.3
22.7
87.4
5
1/900
50/260
147.1
41.1
50.4
10.2
94.3
6
1/1000
50/260
143.1
41.1
50.4
5.0
98.2
10
1/1100
50/260
142.5
41.5
50.8
2.7
98.5
11
1/800
30/260
163.1
27.7
34.0
33.7
81.3
2
1/800
30/120
150.1
44.3
54.2
21.1
88.3
3
1/800
6.8/120
163.1
40.7
49.9
23.0
87.3
4
10/900
50/260
133.3
28.8
35.3
99.3
44.8
8
10/900
10/120
133.3
31.5
38.6
90.9
49.5
7
30/100
50/260
122.2
30.3
145
Increase in Emission
9
10/1000
10/260
-- NO BALANCE OBTAINED -
* Emission reduction is compared to production of methanol by conventional steam reforming of natural gas which produces 180 lb
C02/MM Btu of methanol energy (HHV). Thermal efficiency for a conventional steam reforming plant for methanol production=64%

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Table 3
CARNOL PROCESS III DESIGN
PROCESS SIMULATION - MASS AND ENERGY BALANCES
CARNOL III+
H, - RICH GAS FUEL FOR MDR
1
800
100
640
0
91,9
68.8
82,091
2.4
50
260
156.6
90.9
100.6
58.7
75,114
1.01
50.3
41.1
gl.8
22.7
9.8
UNIT
MDR
Pressure, atm
Temperture, °C
CR, Feedstock, kg
Preheat Temp, °C
CH4 Fuel for MDR, kg
CIL| Conversion, %
Carbon Produced, kg
Heat Load, kcal
Purge Gas for Fuel, kmol
MSR
Pressure, atm
Temp., °C
C02 Feedstock, kg
C02 Conversion, %
Methanol Produced, kg
Water Condensed kg
Energy for Gas Compression to MSR
Energy, kcal
Performance
Ratio, MeOH/CH4, kg/kg
Carbon Efficiency MeOH, %
Thermal Efficiency MeOH, %
Thermal Efficiency C + MeOH, %
CO, Emission, lb/MM Btu
C02 Emission, kg/GJ
12

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Table 4
PRELIMINARY CARNOL PROCESS ECONOMICS
Costs shown in $108/yr and (Unit Costs)
Investable Capital Cost (IC) = $8.46 x 10s*
PRODUCTION COST FACTORS	=	INCOME FACTORS
0.25 IC
Natural Gas
C Storage
C02 Cost
C Income
MeOH Income
C02 Credit
$10
yr
$108
yr
f $ )
>"! O
00
( $ )
Vton)
$108
yr
f—1
{ ton)
$108
yr
[$)
ton)
"S o
00
m
\gal)
$108
yr
/ \
( $
V ton)
{ MSCF )
2.12
2.60
($2)
0.19
(10)
0
(0)
0
(0)
3.78
(0.45)
-1.10
(-25)
2.12
3.90
($3)
0.19
(10)
0
(0)
0
(0)
3.78
(0.45)
-2.40
(-55)
2.12
2.60
($2)
0.19
(10)
0
(0)
1.10
(58)
3.78
(0.45)
0
(0)
2.12
3.90
($3)
0.19
(10)
0
(0)
2.18
(126)
3.78
(0.45)
0
(0)
2.12
2.60
($2)
0.19
(10)
0.42
(10)
0
(0)
3.78
(0.45)
-1.53
(-35)
2.12
3.90
($3)
0.19
(10)
0.84
(20)
3.25
(170)
3.78
(0.45)
0
(0)
2.12
3.90
($3)
0.19
(10)
0.23
(5)
0
(0)
10.95
(1.30)
+4.47
+103
2.12
3.90
($3)
0.19
(10)
0.23
(5)
0
(0)
6.48
(0.77)
0
(0)
2.12
3.90
(S3)
0.19
(10)
4.69
(108)
0
(0)
10.95
(1.30)
0
(0)
*Based on the following plant capacities:
1)	C02 rate, 90% recovered from a 600 MW(e) net [650 MW(e) gross] coal-fired power plant = 4.34 x 106 T/yr
2)	CH4 rate = 2.77 x 106 T/yr = 400,000 MSCF/D
3)	MeOH produced = 2.78 x 106 T/yr = 61,100 bbl/D. = 8460 T/D
4)	Carbon produced = 1.91 x 106 T/yr = 5800 T/D

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Table 5
METHANOL SYNTHESIS EQUILIBRIUM
Input: H, 3 moles
CO, 1 mole
P (atm)
30
30
50
50
T(°C)
120
260
120
260
CO (mole)
0.0007
0.1365
0.0004
0.1089
C02 (mole)
0.4459
0.7686
0.3285
0.6865
H20 (mole)
0.5541
0.2314
0.6715
0.3135
H2 (mole)
1.3391
2.5787
0.9862
2.2773
MeOH (mole)
0.5534
0.0949
0.6711
0.2046
Total (mole)
2.8932
3.8101
2.6577
3.5908
14

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Fig. 1
Simplified Carnol Process for Producing Methanol from Natural Gas
and C02 for Zero C02 Emission
Mass Flows Are In Moles
Flue Gas
0.46 H20
1.73
Power Plant
Stack Gas
C02
1.00
for Process
Natural Gas
3.00
1.73
A 0.46 H2 for
Combustion

Methanol
1.00
METHANOL
SYNTHESIS
REACTOR (MSR)
METHANE
DECOMPOSER
(MDR)
¦^H20
1.00
Air

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c
o
t>
aJ
LL
0
2
1
"t
X
o
>
1.1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Fig. 2
Equilibrium Data for Methane Decomposition, CH4 = C + 2H2
Tot
0
\\ Pressure atm
\
—^
00
200 400 600	1000
TEMPERATURE - degrees Centigrade
1200

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Fig. 3
CO2 Mitigation Technology Carnol-lil + Process
Steam
1 atm
*2.8 kmol
Combustor
A
Alumina or Hex.
MDR
1 atm, 800 °C
640 °C
0.2 kmol
260 °C
2.86 kmol
188°C
Compressor
Carbon to Storage
68.8 kg
CH4 Feedstock
"100 kg, 20°C
CO2 Feedstock From
Power Plant Flue Gas
156.6 kg, 20 °C
Carbon Efficiency 50.3%
Thermal Efficiency 41.1%
C02 Emission 22.7 Ibs/MMBTU
Basis 100 kg CH4 Feed
59.5 kmol 197°C
MSR
50 atm, 260 °C
200 °C
138°C
2.6 kmol
^—CXI—
59.5 kmol
Circulator
Condenser
50 atm, 50 °C
Gas Stream
A
B
C
Rate-Krnol
12.0
70.4
64.0
Tennp-°C
800
260
50
Comp. mol%



CO

3.35
3.68
C02

12.86
14.15
ch4
4.25
17.34
19.08
h2o

4.76
0.14
h2
95.75
56.67
62.34
MeOH

5.02
0.60
MeOH H20
101 kg 58.7 kg
17

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Fig. 4
C02 - H20 - Amine Phase Equilibrium
For Liquid Phase Methanol Synthesis
(Taken from Suda et al.» 1994, Sweden)
KS-1 Extrapol. to 120 °C - ppC02 = 100 psia
Coal Fired Plant
15% C02 Flue Gas
pp CO2 = 2.25 psia
0.01
Hindered Amine C
120°C
MEA 40 °C
MEA 120 C
KS-1 120°C
KS-1 40 X
Hindered Amine C
40 °C
0.6
0.8
0.0 0,2 0.4
C02/Amine Ratio = 0.58-
CO2 In Solution/Amine (mole ratio)
1.0
18

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Fig. 5
Carnol VI Process for CO2 Mitigation Technology
Combining CO2 Recovery From Power Plants with Liquid Metal Methane Decomposition
and Liquid-Phase Methanol Synthesis
Exhaust Gas
(90% C02
Recovery)
PP Flue Gas
MeOH
H20, h2,
CWy Cond. Recycle
Steam
925 C
CW
H2/CH4
Cooler
T, Carbon
Methanol
Product
1-10 atm
HEx.
Carbon
Product
Coal Fired
Power Plant
Ho, COo
C02, H2 1 atm
Flue Gas
30 atm
Nat. Gas
Feedstock
Preheater
Flue Gas
MEA Scrubber
with MeOH Catalyst Slurry
1 atm-40 "C
Liquid Phase
Methanol
Convertor
30 atm
120°C
Me0H-H20
Fractionator
30 atm
PSA - H2/CH4Sep.
Compressor
From 1-10 atm
to 30 atm
Molten-Metal Tin
Methane Decomp.
Reactor
1-10 atm
800°C - 900°C
Feedstock
\	[-»- Product
Process Chemistry: 3/2 CH4 = 3/2 C + 3H2	-<— Nat. Gas, Decomp.
3 H2 + C02 =	CH3OH + H20 -*—- MeOH Synthesis
t	I
Flue	Product
Gas

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Fig. 6
Molten Metal Methane Decomposition Reactor For Carnol VI Process
Basis 1,0 g-mol CH 4 Process Gas

Steam
Gas Comp,
H2 - 2.00 - 90%
CH4 - 0.22 -10%
cw-
H2 = 2.00
7.5 atm
30atm
H2 = 2.00
CH4I.0 g-mol
Feedstock
25 °C 7.5 atm
Pipeline Gas
CO, Flue Gas
M 1.58
Water
Cooled
Conveyor
Carbon
Product
0.15
925 C
11 atm
7.5 atm
700 C
7.5 atm
Comb. Gas
675 C-CH4-1,22
Air
Preheater
7.5 atm
CH4 Fue
0.15
CH4 = 1.22
7.5 atm
Circulator
Flue Gas
5Q°C
1.58
Compressor
PSA CH4/H2
Separator
and
Compressor
Molten Metal Tin
Methane Decomp. Reactor
7.5 atm
20

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