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BACKGROUND OF THE INVENTION
In Baker U.S. Pat. Nos. 4,636,318; 4,842,692; 4,842,728; and 4,923,604 a
chemical reformer is shown in which organic materials such as municipal
waste or coal are chemically reformed by pyrolysis in the presence of
water to form desirable oils and gasses from solid materials. The flow
arrangement is of the continuous process type, using countercurrent heat
exchange so that the organic materials, fluidized with an oil carrier,
enter the system cool and then are removed from the system in a
substantially cool form as well, with the heat being substantially
regenerated from processed outgoing materials to unprocessed incoming
materials.
By this invention, a simplified apparatus for chemical reforming is
provided, capable of performing the desired conversion of organic
materials such as municipal solid waste, coal, hazardous chlorinated
solvents, plastics, ground up rubber tire material, sawdust, or any other
organic material. Thus, in view of the relative simplicity of the
apparatus and method of this invention, organic materials, and even
materials considered as waste products, can be chemically reformed into
mixtures of flammable oils and gasses which may be used as fuel, chemical
feed stocks, or for any other desired purpose.
The apparatus can operate on a continuous process, having an inlet for raw
materials, and one or more outlets for the product oils, gasses and
solids. The reformed products of the apparatus of this invention may be
removed from the system in relatively cool form so that heat is
regenerated and not wasted. The relative amounts of gas and oils produced
can be adjusted throughout a desired range, particularly by control of the
maximum temperature achieved by the organic materials as they pass through
the apparatus.
The apparatus of this invention is also capable of reforming halogenated
plastics and solvents, many of which are considered to be hazardous
materials having a significant environmental threat. Such materials can be
passed through a pyrolysis apparatus for chemical reforming similar to the
apparatus of this invention, to be converted back into simple,
non-halogenated organic species of molecules, with the halogens being
typically converted back to their less harmful ionic form, for example
chloride.
DESCRIPTION OF THE INVENTION
By this invention, apparatus for chemical reforming of organic materials is
provided.
The tubular housing having a longitudinal axis contains an open-ended tube
which is rotatably positioned in the tubular housing in a manner generally
parallel to the longitudinal axis. The open-ended tube carries radially
extending projections along essentially the entire length thereof.
Means are provided for rotating the tube, for example a motor and shaft,
connected to rotate the tube through means as shown below.
First access port means are positioned adjacent one end of the tube and
housing. The first access port means communicates with a tubular space
between the tube and housing, although added communication with the bore
of the tubing at the same end is not necessarily precluded.
Second access port means are also provided, communicating with the bore of
the tube at the one end.
The housing defines means adjacent to the end opposed to the one end, for
forming a flow path between (1) the space between the tube and the housing
and (2) the bore of the tube. This may be a closed housing end, spaced
from the opposed tube end.
Rotation of the tube typically causes fluid material within the housing to
move in a path between the first and second access ports. The rotating
means is typically set to rotate the tube in a direction to so move the
fluid material from the first access port toward the second access port.
To accomplish this, in one embodiment, an outer spiral vane first catches
fluid, organic material from the first access port and urges it through
the space between the tube and housing in a flow path extending from the
one end of the tube and housing to the opposite end. Then, the flow path
permits the fluid, organic material to move around the opposite end of the
tube and to enter the bore, in which an inwardly extending spiral vane,
set in the opposite spiral direction, continues to urge the fluid organic
material to flow along the tube within the bore thereof back to the one
end again, from where the fluid material may pass out of the system
through the second access port means. However, if desired, the apparatus
may be run in the opposite direction.
Alternatively, the apparatus for chemical reforming of organic materials
may comprise a tubular housing having a longitudinal axis as in the
previous embodiment, the radially extending projections comprise hollow,
radially extending convolutions which define radially extending spaces
both inside and outside of the tube, with the tube serving as a heat
exchange wall for material being processed as it flows longitudinally
along the tube first on one side and then on the other side thereof.
A helical member may be carried on the tube to typically extend essentially
along the entire length of the tube. Such a helical member may comprise at
least part of the means for causing the fluid material within said housing
to move in a path between the first and second access ports. Additionally,
pumps may be provided if desired to further facilitate flow of said fluid.
The means for rotating the tube may comprise a motor having a rotary shaft.
The tube, in turn, may have a rotary driving shaft which is driven by the
rotary shaft, but connected thereto in a manner to permit lateral play
therebetween. Thus, the tube exhibits a degree of lateral motion relative
to the rotary shaft during rotation.
Specifically, the rotary driving shaft and rotary shaft may each carry a
radially extending flange, one of the flanges carrying pins which extend
in loosely-fitting manner through apertures of the other of said flanges
to permit such lateral play or motion.
Means may be provided for heating the housing adjacent to the opposed end
and spaced from the one end. In this circumstance, the fluidized organic
material enters into the flow path, preferably passing first along the
tube between the tube and the housing toward the heated, opposed end. As
the fluid material travels toward the opposed end, fluid material that is
heated is traveling again toward the one end through the bore of the tube,
in countercurrent flow and heat exchange relationship with the incoming
material, so that heat is transferred from the hot, outbound material to
the cool, inbound material. Thus, by the time that the inbound material
gets to the opposed end of the tube within the housing it is already
heated, while by the time the heated material gets back to the one end of
the housing through the bore of the tube, it has been cooled by heat
exchange flow relation with the inbound fluid materials.
Typically, the chemical reforming apparatus of this invention operates with
water as an ingredient, typically in the form of supercritical steam.
Specifically with carbonaceous materials such as coal, a fluid organic
material provided to the system through the first port means is an oil
slurry of coal containing typically sixteen to twenty percent of coal, so
as to be fluid. This input mixture may contain up to about fifty percent
by weight of water, based of the coal present, if it is desired to convert
a maximum amount of the coal present to oil. However, if that much water
is added to the coal oil slurry in the initial mixture passed through the
first port means, one may obtain some "burping" resulting from slugs of
vaporizing water. Thus a preferred technique of providing water to the
system is to directly provide it to the heated, opposed end area as steam,
to serve as a reactant for the coal or other desired organic materials.
Typically, the maximum temperature that the fluid material for a reaction
encounters should be above 376.degree. C., a temperature at which water
normally begins to dissociate and thus becomes strongly chemically
reactive, although it is contemplated that with certain catalysts the
reaction temperature might be lower, for example 350 degrees. For the
production of oil, the maximum temperature of the system typically is not
allowed to go above 430 degrees C., because above such temperatures, large
amounts of organic gas are formed and lower percentages of oil. Of course,
if it is the gas that is desired, then the maximum operating temperature
of the system may be substantially above 430 degrees.
The system may be operated under significant amounts of pressure. However,
pressure is not strongly critical in many circumstances, except that it is
generally preferred to operate at a pressure of at least about 50 p.s.i.
and typically about 150 p.s.i. to avoid the formation of large bubbles,
which might interfere with the transport of solid components of the fluid
material through the system. There appears to be no practical upper limit
for the pressure used, and the apparatus will operate at pressures of 30
p.s.i. or effectively ambient pressures, subject to the problem of the
creation of excessively large bubbles.
The apparatus of this invention may also be used to process any organic
materials into oil and gas, for example municipal solid waste, paper,
sewage, slaughterhouse or food processing waste, plastic, sawdust, tree
branches, leaves, grass clippings and the like. The amount of water added
is preferably adjusted in a manner responsive to the degree of oxygenation
and hydrogenation of the input materials. In other words, generally more
water will be added to a coal ingredient to provide desired hydrogenated
products than will be added to an input material comprising paper,
garbage, or grass clippings, since such materials already are highly
hydrogenated and oxygenated.
Preferably, the second access port may comprise an oil and gas-storing
receptacle which carries separate gas-venting and oil-removing ports. For
example, the oil and gas-storing receptacle may communicate with the bore
of the tube described above by a conduit which extends upwardly through
and from the housing, so that gasses and pressurized liquid will move
upwardly into the receptacle, but solids will not. Then, the gas may be
bled off by a valved port extending upwardly from the receptacle, while
oil is tapped off by a lower valved port in the receptacle. However, other
separation techniques may also be used.
Preferably, a downwardly-extending dead leg conduit is also provided
through the housing adjacent the one end of the tube, to receive solid
materials from the bore of the rotating tube. Thus, products and
byproducts of the process of this invention may be continuously collected,
as a continuous flow of organic materials passes through the system.
Typically, the organic materials passed through the system are fluidized
with oil to any degree necessary to assure free flow of the materials
through the system.
Thus, by this invention, organic materials may be chemically reformed,
typically by advancing an oil-fluidized organic material within a tubular
housing from a cool end to a heated end of the housing and back again. The
effect of this is to heat the organic material at the heated end to a
reaction temperature, followed by withdrawing the heated organic material
from the heated end toward the cool end in countercurrent, heat-exchange
relation with more of the advancing organic material. Then, one removes
the withdrawn organic material from the housing at a position adjacent the
cool end.
Preferably, as previously stated water, typically as steam, is added to the
organic material adjacent the heated end, the temperature of the organic
material at the heated end being usually sufficient to cause the water as
supercritical steam to chemically react with the organic material.
By this invention, one may chemically reform halogenated organic materials,
if desired in a mixture with other organic materials for processing, and
typically diluted with a carrier oil, which method comprises advancing
through a process path a fluid mixture of halogenated, organic material
such as polyvinylchloride plastic, dioxin, trichloroethylene, Freons, or
other halogenated solvents or plastics. The fluid mixture includes or is
in contact with an electron donating material, with the mixture being
advanced along the process path that comprises a heating section. By this
heating section one raises the fluid mixture to a temperature at which at
least most of the halogen atoms of the organic material are converted to
halide. For example, in the presence of metals such as calcium, magnesium,
aluminum or iron, each of those materials will donate electrons at an
appropriate reaction temperature of, for example, 250 to 400 degrees C. so
that carbon bonded chlorine atoms may be converted to chloride. Aluminum
and iron can donate electrons to the halogen atoms to convert them to the
halide, with the resultant formation of aluminum chloride or iron
chloride. Thus, ground up, non-toxic scrap metals such as aluminum and
steel cans, a so-called "waste product", may be added to the fluid mixture
in accordance with this invention to convert carbon bonded chlorine atoms
to the harmless chloride form, thus eliminating the halogenated organic
materials, which up to the present time must be otherwise dealt with
elaborate and costly disposal methods because of their long persistence in
the environment, their toxicity, and their accumulation in the tissues of
animals and people.
Other materials which can be added to effect the reaction include alkali
metal or alkaline earth oxides or hydroxides such as sodium hydroxide,
calcium oxide or hydroxide, or magnesium oxide or hydroxide.
DESCRIPTION OF DRAWINGS
In the drawings, FIG. 1 is a transverse sectional view of an apparatus for
chemically reforming organic materials;
FIG. 2 is an enlarged sectional view taken along line 2--2 of FIG. 1;
FIG. 3 is a transverse sectional view of another embodiment of the
apparatus of this invention for chemically reforming organic materials;
FIG. 4 is an enlarged sectional view taken along line 4--4 of FIG. 3; and
FIG. 5 is an enlarged sectional view taken along line 5--5 of FIG. 3.
DESCRIPTION OF SPECIFIC EMBODIMENTS
Referring to the FIGS. 1 and 2, apparatus 10 for the chemical reforming of
organic materials is provided, which comprises the following. A tubular
housing 12 carries in its bore an open-ended stainless steel tube 14,
optionally lined with a protective layer and rotatably mounted on shafts
16, 18 through apertures in housing 12, with shafts 16, 18 being connected
to the inner wall of tube 14 by spider supports 20, 21. Shaft 16, connects
to motor M for rotation so that tube 14 may be rotated as desired.
Tube 14 carries an external spiral vane 22 about its outer surface as
shown, to serve as an auger drive to convey materials through the length
of housing 12.
Tube 14 also defines an internal spiral vane 24 extending from the inner
wall of tube 14 in the opposite spiral sense from spiral vane 22, to serve
as a further propulsion means for fluid materials in the system, passing
through the bore of tube 14.
Thus, fluid materials such as a slurry of 10 to 25 (e.g. 18 percent) coal
by weight in an oil (such as used motor oil) can be inserted into the
system through the first access port 26. Access port 26 is generally
schematically shown, but it may comprise a metering system such as a lock
hopper of a star wheel of generally conventional design, for control of
the amounts of solids to be inserted into the system. Liquids may be added
by a metering pump.
First access port 26 communicates with the tubular space 28 between tubular
housing 12 and tube 14. In this embodiment, motor M rotates tube 14 in a
clockwise manner from the viewpoint of motor M, to urge fluid materials in
tubular space 28 to the right, away from motor M and first access port 26,
down the length of tubular housing 12.
A conventional oil or gas burner system 29, positioned within a fire box
30, is provided at the end 32 of housing 12 which is opposed to the end of
the housing facing motor M. The opposed end portion 32 of housing 12 may
be strongly heated at a desired rate to heat the entire system.
Thus, as tube 14 is rotated in clockwise manner and as fluidized organic
materials pass through tubular space 28 toward opposed end 32 of the
housing, materials which have been previously heated and are present in
space 28 adjacent end 32 are forced into the bore of tube 14, where they
are captured by internal spiral vane 24 and urged to flow back toward the
first end 33 of housing 12, from where they originally came through access
port 26. As the heated material in the bore of tube 14 flows to the left,
it flows by more cool input material from first access port 26 moving
outside of tube 14 to the right, so as to engage in countercurrent heat
exchange with such material through tube 14. Thus, the material flowing to
the right in tubular space 28 arrives at end 32 in heated condition, while
the output fluid material flowing through the bore of tube 14 arrives at
end 33 in cooled manner.
The system of flowing fluid may be pressurized by adding pressurized air or
oil through access port 26, for example, so that fluids and gasses may be
forced to enter into lock hopper 34, from where gasses may be vented
through upper valve outlet 36 and oils may be tapped to flow through
vented tap 38, in a manner as indicated by pressure gauge 40 and liquid
level sight glass 42. On the other hand, solid materials may drop through
valved dead leg conduit 44, to at least partially separate the solid,
liquid, and gaseous product components of the apparatus of this invention.
It is preferred to provide water in the form of steam to the system at a
point where the reacted materials are hot, although water may be added
through port 26 with material for processing. Pressurized water from a
supply source such as a simple tap 46 may pass through conduit 48 into
fire box 30, there having a section 50 that extends through the fire box
in serpentine manner so that the water may be heated to steam and driven
by the water pressure along conduit 48 into the heated space within
housing 12 through aperture 51. There, the live steam mixes with the other
reactants, preferably at a temperature above 376 degrees C. at which the
water molecules tend to dissociate, to serve as a reactant and source of
hydrogen for the other organic materials being reformed, such as coal,
garbage, or the like. Thermocouple 54 may measure system temperatures for
control of the process.
The maximum temperature of the reaction flow system is of course adjacent
end 32 of the housing. Then, the heated material flows through the bore of
rotating tube 14, impelled by internal spiral vane 24. At the hottest end
of the reaction flow path, the temperature is high enough for typically a
myriad of chemical reactions to take place, especially as cooling begins.
However, as the system cools, reactions take place that typically favor
the formation of oils and gasses, and then they cease, so that there is
typically a net production of oils and gasses in the output product as
found adjacent end 33 of the housing, when compared with the input
reactant. These oils and gasses serve as useful fuels, among other uses,
comprising a large variety of species of molecules.
As previously stated, if it is desired to maximize the production of oils,
it is generally preferred to not exceed a maximum operating temperature
adjacent end 32 of the housing of 430 degrees C. At temperatures higher
than that the production of gasses will increase, which gasses also serve
as useful fuels.
As another alternative, coal may be added to the system, particularly high
sulfur coal, to yield a lower sulfur oil as a product. Another resulting
product is a low sulfur, oil impregnated coal having a very high BTU upon
burning. Most of the sulfur comes off as a gas. Thus, by this method and
apparatus, high sulfur coal can be turned into environmentally safer,
useful, high BTU combustion products.
The apparatus of this invention utilizes a relatively small amount of heat
consumption as provided by burner 29, because the heat is largely
regenerated between the output product and the input reactant. Thus, the
apparatus operates in a very energy efficient manner.
If the organic input material added through first access port 26 contains
halogenated material such as polyvinylchloride plastic or halogenated
solvents, it is typically desirable to include in the slurry an electron
donating material, for example finely ground-up, recycled cans or other
scrap metal in a stoichiometric amount, or preferably in an excess to the
amount of chemically bonded chlorine present. Alkali conditions can
accelerate the reaction. The resulting product can be expected to be of
greatly diminished carbon-bonded chlorine content.
If the residue of carbon-bonded chlorine remains too high, the product may
be sent through another processing apparatus similar to the apparatus of
this invention, for further chemical purifying and reduction of chlorine
to chloride. If desired, steel and aluminum may be used as an initial
"reagent" for reforming most of the chemically bonded chlorine to
chloride, followed by a "clean-up" second processing using, if necessary,
calcium or magnesium metal which, of course, is highly reactive to
chlorine, quantitatively converting it to chloride.
Referring to FIGS. 3-5, outer tubular housing 56 is provided, carrying at
one end thereof a housing heating system which is of similar design to the
heating system of the previous embodiment, so a second description thereof
is unnecessary.
Inflowing material may be provided through a flow pump and pressurizing
system 58 which may be of conventional design, the flowing material being
provided to inflow unit 67. The flow material passes in this embodiment
through the space 74 between tubular housing 56 and an inner, rotatable,
convoluted reactor tube 76, along the length of reactor tube 76 away from
inflow tube 67 to exit the end 78 thereof within the closed end of tubular
housing 56.
Reactor tube 76 may be of a convoluted cross section as particularly
illustrated in FIG. 5, so that a plurality of outer convoluted pockets 80
and inner convoluted pockets 82 are defined, extending along the entire
length of reactor tube 76 to provide flow channels for material being
processed both outside and inside of reactor tube 76.
The reaction material thus passes through space 74, as previously stated,
to the end 78 of reactor tube 76, at which point the material from the
outer pockets 80 can fill end space 84 and from there flow into the open
ends of inner pockets 82, back along the interior of tube 76 in
countercurrent heat exchange flow relation with the material in outer
pockets 80.
A helical rod or tube 86 is wound about reactor tube 76, and serves to
provide agitation and flow assistance to the materials in space 74. Tube
76 is rotated by motor M through shaft 62, in this case in a clockwise
direction to cause rotation of helical rod 86 and added pumping action,
above and beyond the effect of the pump in unit 58.
By the pumping pressure, materials within inner pockets 82 are advanced
back again along reactor tube 76. Plate 77 closes off the near end of tube
76 so that the contents flow through tube 79, past inlet tube 67, into end
space 90, including area between flanges 94, 96. From there, gas which has
been formed rises into gas collecting chamber 64, while flowable liquid
materials flow downwardly into outflow pipe 66.
Pressure pipe flanges 61 are shown, with reactor tube 76 being rotated by
motor M through a solid power shaft. Outflow materials pass to either drop
through outlet line 66 or gas collecting chamber 64. Stationary seal 68
engages rotating seal 69, which rotates on hollow power shaft 79 to
provide the desired seal to separate inflowing reactant and outflowing
product.
Power coupling 92 connects hollow power shaft 79 with the solid power shaft
62 in a manner also illustrated in FIG. 4. Solid power shaft 62 carries a
first flange 94, while hollow power shaft 70 carries a second flange 96.
Second flange 96, in turn, defines a plurality of pins 100, each of which
occupies an aperture 98 which is carried in first flange 94. As shown,
apertures 98 are of substantially larger diameter than pins 100.
As a result of this, as motor M rotates reactor tube 76, the second flange
96 and reactor tube 76 exhibit an amount of transverse play which is
governed by the degree that apertures 98 are of larger diameter than pins
100. This continuous play provides an additional means to prevent the
plugging up of the materials being processed in the apparatus as it
operates.
If desired, fluid material outlet line 66 communicates with a second pump
and a pressure-down unit 102, so that the materials are passed through the
apparatus by the action of the pump of unit 58, the pump of unit 102, and
helical pump action of helix 86. Also, a pressure-up unit of assembly 58
and the pressure down unit of assembly 102 (conventional items) may be
used to operate the system at any desired pressure.
Gases may then be released by vent 104 as appropriate during the process.
Apart from the above, this embodiment of FIGS. 3-5 may function in a manner
similar to that of the previous embodiment. As before, halogenated organic
materials may be reformed to primarily hydrocarbon and chloride materials
as previously described.
Thus, a process and apparatus is provided which, with substantial
simplicity, converts organic materials into desirable products such as oil
and gas fuel, plus oil impregnated carbon. As previously stated, sulfur
can be removed from coal by this process as an extra dividend, improving
its environmental acceptability. Also, the system operates with a low
energy cost and, typically, at relatively low pressures.
The above has been offered for illustrative purposes only, and is not
intended to limit the scope of the invention of this application, which is
as defined in the claims below.
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