Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
Case: ICR 3061
S
A~COHOL DISSOCIATION PROCESS FOR AUTOMOBILES
.... . . _ .. _ _
BACKGROUND OF THE INVENTIO
Kosaka et al U.S. Pa-tent ~lo. 4,088,450 discloses
a plurality of catalysts arranged iII a desirable order
based on the temperature gradient existing in the
chamber for reaction. The operating temperature of the
catalysts and the temperature of the portion of the
reaction chamber it is in, are matched so a~ to avoid a
catalytic degradation and/or catalytic inactivity.
Peterson et al U.S. Patent No. 4,282,835
provides for synthesizing CO and H2 fuel from methanol
and water in a second synthesizer. The methanol is
confined in an alcohol tank as a liqui~. The water is
confined in a water tank. A fuel pump and a water pump
force fuel and water to a mixing valve. A heat exchanger
heats the fuel and water to a gas which passes through
nickel on alumina catalyst at 500C where the methanol
dissociates to CO+H2. The gas passes to a second
synthesizer containing Fe on Alumina catalyst above
500C where water and carbon monoxide form hydrogen and
carbon dioxide. The gas is then mixed with air and
passes to the engine.
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Case: ~CR 3061
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SUMMARY OF ~HE INVENTION
According to the present invention, one embodiment
consists of a reactor for providing fuel vap~r to and for
treatin~ exhaust gases from an internal combustion engine,
which reactor comprises:
(a) elongated reaction chamber means having inlet and
outlet means disposed at substantially opposed ends of said
chamber means;
(b) a plurality of longitudinal fins on the interior
wall of said chamber means;
(c) a mass of particulate dissociation catalyst arran-
ged within said chamber means and in heat exchange contact
with said fins;
(d) means for supplying methanol to said inlet means,
and means for conveying gaseous dissociation product from
said outlet means to the fuel intake of said engine;
(e) housing means surrounding said chamber means and
having a gas supply opening and a gas discharge opening,
said openings being disposed in substantially opposed faces
of said housing means; and
(f) means for conveying exhaust gas from said engine
to said yas supply opening.
According to another aspect of the invention is pro-
viding a reactor for providing fuel vapor to and for treating
exhaust gases from an internal combustion engine, which
reactor comprises:
(a) elongated reaction chamber means having inlet and
outlet means disposed at substantially opposed ends of said
chamber means;
(b) a plurality of longitudinal fins on the interior
wall of said chamber means;
Case: ICR 3061
6~
-- 3
(c) a mass of particulate dissociation catalyst
arranged within said chamber means and in heat exchange
contact with said fins;
(d) means for supplying methanol to said inlet means,
and means for conveying gaseous dissociation product from
said outlet means to the fuel intake of said engine;
(e) housing means surrounding said chamber means and
having a gas supply opening and a gas discharge opening,
said openings being disposed in substantially opposed faces
of said housing means;
(f) combustion catalyst within the space between
said chamber means and said housing means; and
(g) means for conveying exhaust gas from said engine
to said gas supply opening.
Further, in one embodiment, a method of methyl alcohol
treatment and distribution for an automobile internal com-
bustion engine is provided, including the sequence of steps
as follows:
(a) heating a catalyst bed reactor to a start-up
temperature using exhaust gas from an internal combustion
engine being operated on atomized methyl alcohol, said
catalyst bed reactor comprising a partial combustion catalyst
and a methanol dissociation catalyst;
(b) isolating said catalyst bed reactor from said
exhaust;
(c) vapori~ing liquid methyl alcohol to form alcohol
vapor;
(d) mixing said alcohol vapor with air in a constant
ratio of oxygen to alcohol at variable alcohol flow rates,
to form a partial combustion mi~ture;
(e) contacting said partial combustion mixture and
said partial combustion catalyst to exothermically form a
9~
- 3ta) -
dissociation mixture, said dissociation mixture comprising
methanol vapor, water vapor, earbon monoxide, and hydrogen
each in substantial proportion;
(f) eontaeting said dissoeiation mixture and said
dissociation eatalyst to endothermieally form a hydrogen-
rieh fuel, said hydrogen-rich fuel comprising hydrogen and
carbon monoxide each in substantial proportion, said
hydrogen-rich fuel being formed from said alcohol vapor
substantially adiabatieally;
(g) mixing air and said hydrogen-rich fuel to form
a total eombustion mixture; and
(h) burning said total eombustion mixture in an
internal eombustion engine.
Case: ICR 3061 1~99~5
BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a cross-sectional view of a
reactor in accordance with the present invention.
Figure 2 is a longitudinal cross-sectional
view of a reactor in accordance with the present
invention.
Figure 3 is a schematic flow diagram of an
automobile fuel system in accordance with the present
invention.
Case: ICR 3061
DETAILED DESCRIPTION O~' TH~ INVENTION
With more particular reference to the drawings,
it is seen in Figure 1 that a reaction chamber 10 is
supported within the reactor 3 by supports 16 and/or by
springs 14 and 14'. The reactor chamber wall 10 encloses
the catalyst bed material 11. Inner fins 9 extend from
the reaction chamber wall 10 to which they are attached.
The inner fins extend from the reaction chamber wall
inwardly into the reaction chamber defined by the
reaction chamber wall. Outer fins 13 are connected to
the reaction chamber wall 10. Outer fins 13 extend
outwardly from the reaction chamber wall 10 into the
heat exchange chamber 12. The heat exchange chamber 12
is defined by the inner surface of the hea-t exchange
wall 17 and the outer surface of the reaction chamber
wall 10.
As shown in Figure 2, the heat exchange wall
17 encloses the reaction chamber wall 10. The sup-
porting spring means 14 and 14l are connected to the
inner surface of the heat exchange wall 17 and the
outer surface of the reaction chamber wall 10.
As shown in Figure 3, the reactor 3 is
connected by conduit 19 to a super-heater 5. The
superheater 5 receives vapor phase alcohol from the
vaporizer 2 through line 20. Air is pumped through
line 15 from compressor 21 into line 20. The mixture
of air and methanol vapor passes through line 20 to the
superheater 5. Alcohol from the alcohol tank 1 is
pumped thxough line 22 by pump 23 to the vaporizer 2.
Valve 24 in line 22 is provided to limit the flow of
Case: ICR 3061 ~ 5
liquid alcohol to the vaporizer 2 from the alcohol tank
1. The mixture of air and alcohol vapor passes through
line 19 into the reactor 3. The reactor 3 is heated by
exhaust gas from the engine 4. The exhaust gas passes
through line 25 to the reactor 3. The line 25 has
valve 26 therein to limit the flow of exhaust gas to
the reactor 3. Exhaust gas leaves the reactor 3
through line 27. The vaporizer 2 is provided with a
line 29 through which hot engine coolant is passed from
the engine to the vaporizer 2. Engine coolant passes
from the vaporizer 2 through line 30. Line 30 is
connected to engine 4. The filter 6 is connected to
the reactor 3 by line 31. The filter 6 removes solids
from the hydrogen rich gaseous mixture passing there-
through. The filter 6 is connected by line 32 to theengine 4. Valve 36 in line 32 is provided to limit
the flow of the hydrogen rich gaseous fuels in the
engine. The valves 24 and 36 completely block the
dissociation system including vaporiz.er to the filter
when the system is not in operation. Line 8 is connected
to the line 33. Line 33 is connected to the engine 4.
Hydrogen rich gas in line 32 mixes with air from line 8
in the line 33~ Liquid alcohol passes through line 7
to ].ine 33. The valve 34 in line 7 limits the flow of
liquid alcohol therethrough. The liquid alcohol passing
through line 7 is atomized prior to being fed to the
engine 4.
The preferred alcohol for use as the alcohol
fuel in the alcohol tank 1 is methanol.
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Case~ R 3061
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The fins 9 and 13 extend the length of the
reaction chamber wall. Both the inner fins 9 and the
outer fins 13 serve to distribute heat along the
reaction chamber wall. Inner fins 9 serve to distribute
heat into the reactor bed 11 from the reaction chamber
wall 10. The outer fins 13 serve to transfer heat from
the heat exchange chamber 12 into the reaction chamber
wall 10.
The ends of reaction chamber wall 10 are
preferably covered by a screen or wire mesh (not shown)
to retain the catalyst bed 11 therein.
The engine is started by methods known in the
art for starting internal engines for example by use of
an alternate fuel such as liquid methanol delivered
through line 7 or a gaseous fuel like propane. After
starting the engine, the hot exhaust gases heat the
r~actor 3 by passing through the heat exchange chamber
12. The outer fins 13 conduct heat from those hot
exhaust gases and transmit it to the reaction chamber
wall 10. The fins 9 transfer heat from the reaction
chamber wall 10 into the reaction bed 11. When the
initial operating temperature is reached, the mixture
of air and methanol vapor are fed to the reactor.
Preferably the reactor contains a dual catalyst bed.
The initial catalyst contacted by the mixture of air
and methanol vapor being a partial oxidation catalyst
for example copper/nickel. The subsequent catalyst
contacted by the alcohol and partial combustion product
mixture bein~ a dissociation catalyst such as copper/
zinc catalyst. Partial combustion occurs between the
methanol and the air in the initial stage of the
reactor 18. This paxitial combustion produces heat.
The heat produced in the initial stage o~ the reactor 3
is transferred to the subsequent stage by the inner
fins 9.
Case: ICR 3061 ~ 5
-- 8
Once the catalyst bed is preheated to -the
initial reaction temp~rature by the engine exhaust gas,
valve 26 is closed and valves 24, 35 and 36 are opened
by temperature switch. Valve 28 is line 38 is first
opened to send hot exhaust gas to the superheater 5
before closing valve 26. The reaction temperature
within the reactor 3 is maintained by the rate o~
partial combustion. The rate of partial combustion is
controlled by the amount of air injected through line
15 by control of valve 35. Valve 35 is temperature
responsive to the outlet gas temperature in line 31.
Valve 35 is connected to line 31 by temperature control
signal. The temperature control in line 31 is not
shown. Valve 35 is also connected to line 22 by flow
rate sensor signal. The flow rate sensor signal sets
the maximum opening of valve 35 at the measured alcohol
flow rate. The temperature control signal reduces the
opening of valve 35 to lower the air ~low rate from the
maximum if the temperature is over the specified upper
limit of the product gas temperature. This air flow
control may be done by microprocessor which is not
shown in Figure 3.
During cold start ot exhaust from the engine
passes into the heat exchange chamber of reactor 3
through line 25 and valve 26. The exhaust leaves the
heat exchange chamber through line 27. While the
reactor is being heated up to the operational temperature,
valve 28 in line 38 is closed so that exhaust from line
37 passes into line 25 and into the heat exchange
chamber of the reactor 3. The exhaust ga~ leaving the
reactor 3 through line 27 enters the superheater 5
through line 39 and leave the superheater through lines
40 and 74 to vent. Valve 44 in line 45 is closed
during this period. During this period the vaporizer 2
Case: ICR 3061
;5
is heated with engine coolant. When the reactor has
reached its operating temperature, valve 28 in line 38
is opened by a temperature switch so that exhaust no
longer passes from line 37 into line 25 but rather the
exhaust from line 37 is channelled into line 39. The
valve 26 is then closed. Thus, the reactor 3 is
isolated from exhau~t heat and adiabatic dissociation
begins in the reactor. The valve 44 controls the
exhaust gas flow to the superheater 5 to give the
temperature of the methanol vapor from the superheater
5 at the specified inlet temperature for the adiabatic
reactor 3. The vaporizer 2 is optional. Thus, li~uid
methanol may be fed directly into the superheater 5
from the methanol or alcohol storage tank 1. Altexna-
tively engine exhaust may be passed from the outputline 40 of the superheater 5 into the feedline 29 of
the vaporizer 2. In which case, engine coolant would
not be fed into the feedline 29 of vaporizer 2.
The air being fed through line 15 may be
preheated by preheater 41. The preheater ~1 may be fed
exhaust from line 37 to provide the preheating heat for
air being fed through line 15 into line 20~ Beneficially
the preheated air does not lower the temperature of the
liquid alcohol and/or alcohol vapor being fed to the
superheater 5 through line 20.
The reactor 3 preferably is provided with
insulation over the heat exchange wall 17 to maintain
the temperature therewithin and minimize the transfer
of heat therefrom. As an alternative to valve 26, a
restricting orifice may be provided. ~uring cold start
hot exhaust gas flows through the orifice to the reactor
to preheat the catalyst bed in reactor 3 to operating
Case: ICR 3061 ~9~
-- 10 --
temperature by closing the valve 28 in line 38. When
the reactor 3 is in operation, the orifice allows only
a portion of hot exhaust gas to flow to the reac-tor 3
with the balance of the exhaust gas flowing through
line 38 by opening the valve 28. In this manner, the
heat loss from the reactor 3 can be minimized and some
heat recovery from the exhaust gas may be realized in
the reactor.
The principal function of exhaust within the
heat exchange chamber of the reactor 3 is to initially
heat up the reactor 3 and then to sustain heat losses
to the atmosphere to maintain the temperature of the
reaction chamber 11 free from heat loss to the atmos-
phere. After the initial heat up of the reactor 3 to
the operating temperature, a major portion of the
exhaust in line 37 may be passed to the vaporizer
and/or superheater. Thus only a small portion of the
exhaust would be required to make up for heat losses
from reactor 3 to the surrounding atmosphere. It is
within the scope of the invention to completely block
the flow of exhaust to the reactor 3 after it initially
reaches operating temperature. In this case the heat
losses to the atmosphere would be made up by the
additional partial combustion of methanol.
Physical Confi~uration and Functions of Reactor Components
Figures 1 and 2 show the schematics of
reactor 3. The reactor has two divided sections: the
inner section holding the catalyst bed and the sur-
rounding empty chamber. The reaction chamber wall 10,
separating the catalyst bed 11 and the heat exchange
chamber 12, has inside fins 9 and outside fins 13.
During cold starts the hot engine exhaust gas flows
through the heat exchange chamber to provide the heat
Case: ICR 3061
required for preheating the bed to a desired temperature.
The fins on the reaction chamber wall will enhance the
heat transfer and, thus, reduce the preheating time.
During normal dissociation operation, the heat exchange
chamber is isolated from the exhaust gas flow and,
thus, acts as insulation. The feed to reactor 3 is a
mixture of superheated methanol and air. For thermally
neutral conversion of methanol, the air/methanol ratio
in the feed and the reactor inlet temperature are
controlled.
The fins inside and outside of the reaction
chamber wall are placed parallel to the flow directions
of the reactants in the bed and of the exhaust gas in
the heat exchange chamber, respectively, in order to
minimi~e the pressure drops in both flows.
The inside fins on the reaction chamber wall
have important functions for maintaining catalyst
activity and physical integrity~ During adiabatic
operation the fins will help to maintain a more even
temperature distribution in the bed by facilitating
longitudinal heat transfer. This heat transfer effect
is beneficial to the maintenance of the catalyst
activity by reducing the peak temperature generated by
the reaction between methanol and oxygen in the front
partial combustion zone o the catalyst bed, since a
higher temperature deactivates catalyst more by
sintering. Further, the inside fins may be beneficial
for catalyst pellet integrity by restricting pellet
motion resulting from sudden changes in car speed or
car vibrations due to rough road conditions.
Case: ICR 3061 ~9~
- 12 -
As shown in Figure 2, springs 1~ and 1~' or
some other mechanical means of dampening motion may be
installed in the heat exchange chamber to absorb any
abrupt movements of the automobile without detrimentally
affecting catalyst physical integrity.
Because a rapid preheating of the catalyst
bed by heat exchanger is required during cold starts, a
reaction chamber wall shape that gives a larger heat
transfer area is preferred at the same catalyst volume.
For this reason the reaction chamber wall also has many
inside fins 9 and outside fins 13. Figures 1 and 2
show a configuration of the reactor. Figure 1 shows
that the reaction chamber wall in the reactor has a
large width-to-depth ratio in order to have a large
peripheral surface area at the same volume.
Since the reactor must fit into the available
space in an automobile, the reactor size and shape must
correspond to that space.
Overall Fuel System
Figure 3 sho~s a schematic flow diagram of
the automobile fuel system of the invention. Major
components of the fuel system are a vaporizer 2, a
superheater 5, a filter 6, and by-pass line 7 in
addition to the reactor.
In the vaporizer 2 the engine coolant,
normally at 200-220F, provides the heat for the
methanol vaporization. In the superheater, the methanol
temperature is raised to the desired reactor inlet
temperature by heat exchange with the exhaust gas. The
vaporizer 2 is optional because the superheater may be
used for the methanol vaporiza-tion and superheating by
directly feeding liquid methanol into it. Air is
injected through line 15 to the alcohol feed stream
Case: ICR 3061 ~ 6~
normally before the superheater in order to allow
enough time for mixing of the air and alcohol prior to
the reactor. The fil-ter 6 collects fines from the
catalyst bed.
The by-pass line 7 delivers liquid alcohol
directly to the engine as required during cold start or
high load driving (acceleration or high speed driving).
During cold start, the engine 4 must run on liquid or
vaporized alcohol until the dissociation reactor
completes its start-up phase. During high load driving
the fuel requirement in excess of the ma~imum through-
put of the reactor is provided with liquid alcohol from
tank 1 delivered through the by-pass line 7.
The direct feeding of liquid alcohol in
excess of the maximum throughput o~ the reactor may be
beneficial for overall car performance without signi-
ficantly reducing the benefits of the dissociation.
The liquid alcohol fed to the engine will boost the
engine power by increasing the energy density of the
~o combined fuel when the power is needed at high load
conditions. Further, it may lower the NOX emissions by
reducing the combustion temperature in the engine.
The preferred operating mode for the dis-
sociated methanol engine is to operate for maximum
~S efficiency at low-load driving conditions, and ~or
maximum performance at high-load transient driving
conditions. Low-load operation consisting of idle and
constant speed driving does not require a high power
output from the engine. For low-power output~ the
engine can be operated at a maximum air-fuel ratio or a
minimum e~uivalence ratio to give maximum efficiency.
With dissociated methanol the equivalence ratio can be
reduced as low as 0.3 without hampering smooth engine
Case: ICR 3Q61
- 14 -
operation due to its high hydrogen content. For maximum
power output, methanol in excess of the reactor through~
put can be by-passed and fed directly into the engine.
Air flow is unthrottled. The result is an increase in
5 fuel densi-ty up to an equivalence ratio o~ 1.0, which
gives maximum power output.
Operation can be accomplished with a driver
controlled accelerator that sends a signal to a micro-
processor, which in turn monitors and adjusts engine
performance as necessary. The micro-processor is not
shown in Figure 3. Adjustments such as spark advance,
air-fuel ratio, etc. are made. The micro-processor
maintains the required air-fuel ratio during low-load
driving demand by throttling the air flow to the engineO
During high-load transient demands, such as acceleration
to cruise speed and hill climbing is required, additional
fuel as liquid methanol is injected by opening by-pass
valve 34. In this mode, air-fuel ratio varies as fuel
density is adjusted to give the required engine power0 output and hence good driving performance.
EXAMPLE
Cold Starts
Since the cold start of the reactor requires
hot engine exhaust gas for preheating of the catalyst
bed the engine 4 must be turned on by a method indepen-
dent of the methanol conversion system. During this
period the engine may run on liquid alcohol delivered
through the by-pass line.
Once the catalyst bed temperature in the
reactor has risen to the initial operating temperature,
superheated alcohol is fed to the reactor with air
injection through line 15. Because of the exothermic
Case: ICR 3061 ~ 6S
heat generated by partial combustion of alcohol, the
catalyst bed temperature will further rise until
endothermic alcohol dissociation becomes effective.
For a 20/10 Cu/Ni catalyst on silica the bed
temperature for initiating the partial combustion
reaction for methanol is about 300F or above. A lower
temperature is acceptable if a more active catalyst is
used.
The engine can be started independently with
a gaseous start-up fuel such as propane, electrically
vaporized methanol or finely atomized methanol.
Adiabatic ~lcohol Conversion
Once the cold start phase of the reactor is
completed, the reactor is operated adiabatically with
air injection rate controlled at a fixed 02/methanol
molar ratio in the feed for thermally neutral, adiabatic
conversion. The 02/methanol feed ratio is normally
0.16 for the adiabatic conversion. The ratio is less
than the theoretical number of 0.174 because of the
exothermic formation of such by-products as methane and
dimethyl ether in very small quantities. When the
methanol conversion goes to completion at the air
injection rate and there are no heat loss from reactor
to surroundings, the product gas temperature is the
same as the feed temperature.
With a dual catalyst bed of Cu/Ni and Cu/Zn
catalysts, the fo7lowing three reactions take place as
major reactions
CH30H (g) + 1/2 02 -~ H2 + CO + H20 ~H298 =
-36,134 cal (I)
CH30H (g) ~ 2 H2 + CO ~H298
21,664 cal (II~
H20 (g) + CO -~ H2 + CO2 298
-9,838 cal (III)
Case: ICR 3061
- 16 -
Methanol is first converted via Reactions (I) and (II)
in the Cu/Ni catalyst zone and the remaining methanol
is converted via Reactions (II) and (III) in the
following Cu/Zn catalyst zone. Because Reaction (I) is
very fast on a Cu/Ni catalyst, oxygen is rapidly consumed
to completion in the zone. The rapid progress of
Reaction (I) creates a temperature peak in the zone.
After the depletion of oxygen the endothermic reaction
(Reaction (II)) becomes dominant and, thus, cools down
the bed temperature. The gas leaving the reactor is
very close to equilibrium for the water/gas shift
reaction because of the excellent shift activity of
the Cu/Zn catalyst.
Having thus described the invention by
reference to certain of its preferred embodiments it is
respectfully pointed out that embodiments described are
illustrative rather than limiting in nature and that
many variations and modifications are possible within
the scope of the present invention. Such variations
and modifications may appear obvious and desirable to
those skilled in the art upon a review of the foregoing
description of preferred embodiments.
