Note: Descriptions are shown in the official language in which they were submitted.
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APPARATUS FOR TREATING LIGNOCELLULOSE MATERIAL AND METHOD
ASSOCIATED THERETO
Field of fihe invention:
The present invention relates to an apparatus and method for treating
lignocellulose material, fibrous material, particulate material, and the like,
in a
chamber, with gaseous reagents, such as steam for example, under pressurized
conditions. More particularly, the present invention relates to an apparatus
and
method which is also devised for cooling and discharging such treated material
from the chamber in which gaseous reagents are maintained under pressure, in
such a way that the treated material is discharged without explosive
depressurization which typically results from high temperature gradients.
Background of the invention:
Apparatuses and methods for treating lignocellulose material, fibrous
material, particulate material, and the like, in a chamber with gaseous
reagents,
such as steam for example, under pressurized conditions, are very well known
in
the art.
Known in the art, there is Canadian Patent No. 1,070,537 granted on
January 29ffi, 1980, and naming Brown et al. as inventors, which relates to a
method of feeding fibrous material into a pressurized vessel such as a
digester
operating at approximately 300 pounds per square inch. The raw material is
first
pre-compacted by a screw conveyor and subsequently compacted to a density of
at least 45 pounds per cubic foot of oven dry material to form a plug in a
feeding
conduit communicating with the digester. During the precompacting and
compacting stage, the moisture of the material is maintained at a natural
level of
about 10% to 50% by weight. The plug thus forms a continuously advancing mass
of material which separates the interior of the digester from the surrounding
atmosphere without the need of special valve means normally used in prior art.
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2
The advancement of the plug fakes place along a straight line generally
coincident
with the centreline of the screv~i conveyor but axially spaced from the same.
Also known in the art, there is Unites States Patent No. 4,211,163
granted on July 8t", 1980, and naming Brown et al. as inventors, which relates
to
an apparatus for discharge of pressure cooked particulate or fibrous material.
Particulate or fibrous material, after treatment with gaseous reagents in a
vessel
under pressure in a continuous process, is discharged from the pressure vessel
by
entering a discharge conduit in pressure communication with the pressure
vessel,
and is conveyed through the discharge conduit by means of a feed conveyor
located therein. The feed conveyor compacts the material to form a dense,
subsfiantially gas impervious plug thereof in the discharge conduit against
the
outlet end thereof. The outlet end of the discharge conduit comprises an exit
passage of small cross-sectional area so as to cause compaction of the
material
therein by means of the conveyor. A valve means is provided, movable rapidly
between a fully open position and a fully closed position to permit passage of
the
cooked material therethrough, from the dense, compact plug formed in the
outlet
end of the discharge conduit. Operating means is provided to move the valve
rapidly between its fully opened and fully closed positions, at predetermined
intervals. In this means, the cooked material can be discharged intermittently
at
frequent intervals from a pressure vessel, allowing the pressure cooking
process
to be conducted continuously. The dense compact plug prevents reagent losses
and pressure losses on discharge of the material.
A major problem associated with the above-mentioned types of
apparatuses and methods is that the material being treafed under high pressure
and temperature conditions generally has a tendency to burst and/or defiberize
due to explosive depressurization which results often from high temperature
gradient between the treatment conditions in the vessel and the environment in
which the treated material is discharged. Another problem associated with the
above-mentioned types of apparatuses and methods is that a loss of pressure in
the treatment vessel has been known to arise when the treated material is
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3
discharged from the apparatus due fio the nafiure of the discharged system of
said
apparatuses. Moreover, another substantial disadvantage of the above-mentioned
apparatuses is that there has been known to be possible pressure variations in
the
area close to the discharging outlet of the apparatuses, which is
disadvantageous
as known in the art. In addition, the above-menfiioned apparatuses are
disadvantageous in that the treated mafierial may behave randomly, due to
suction
effects in this area close to the discharge area, because the transfer speed
is
difficult to control. Moreover, these above-mentioned apparatuses are
disadvantageous because they have been known to be subject to a Loss of
volatiles and the treated material which is discharged from the apparatuses is
done under extreme conditions, very often leading to significant impact of the
treated product onto components and conduits of the apparatuses, which as a
result thereof, often require maintenance and/or replacement.
Another substantial problem associated with the above-mentioned
types of devices is that the material to be treated requires to be formed into
a plug,
either at the upstream level of the pressurized vessel, or afi the downstream
level
of the pressurized vessel, so as to ensure that substantial pressure losses
will not
result when the material is either entered or discharged from said pressurized
vessel.
Hence, in light of the aforementioned, fihere is a need for an improved
apparatus and/or method for treating lignocelluiose material, fibrous
material,
parfiiculate material, and the like, which would be able fio overcome some of
the
aforementioned problems.
Summary of the invention:
The object of the present invention is to provide an apparatus for
treating lignocellulose material, fibrous material, particulate material, and
fihe like,
which, by virtue of its design and components, satisfies some of the above-
Q~ 06 r004 CA 02484850 2004-11-05
... ~~/~BREVE:rS 6e 514 845 8705; 08/09/04 1~1 :30; J#g77 CA0300642
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4
mentioned needs and is thus an improvement over ether related apparatuses
andlor methods known in the prior art.
In accordance with the present invention, the above object is achieved
with an apparatus for treating material, said apparatus comprising:
a feed system having an inlet for receiving the material from a supply
source and an outlet for releasing the material;
a reactor for treating the material, the reactor having an inlet connected
to the outlet of the feed system for receiving the material released from the
feed
system, and an outlet for releasing the material treated by the reactor;
a conveyor located inside the reactor for conveying the material from
the inlet of the reactor to the outlet thereof; and
a discharge system far discharging the material, the discharge system
including:
a chamber having an inlet connected to the outlet of the reactor for
receiving the material treated by the reactor, and an outlet; and
a pump connected tv the chamber for pumping liquid into the
chamber sv as tv put the treated material received from the reactor in
liquid suspension, thereby obtaining a liquid suspended treated
24 ~ material, said liquid suspended treated material being dischargeable
from the apparatus through the outlet of the chamber
Preferably, the material is selected from the group consisting of
lignocellulose material, flbrvus material, particulate material, cellulosic
material,
and the like.
Preferably, the outlet of the chamber is provided with a valve, said valve
being operable between a closed configuration for preventing discharging of
the
liquid suspended. treated material from the chamber and an opened
configuration
for allowing discharging of the liquid suspended treated material from the
chamber.
_ ,...__ , ., ...... ..
Empf.~.eit:09/OB~~004 17:~~ '°~NIrENDED SHEET~~S P.O10
Y 09 06~200~~~ CA 02484850 2004-11-05 GA0300642
E.., '_-_. _~~e/BREVE.TS 6e 514 845 8705; 06/09/04 11 :30; JetFax #977, -._~ ,
,
according to another aspect ofi the present invention, there is also
provided an apparatus for treating solid iignocellulose material, said
apparatus
comprising:
a feed system having an inlet for receiving the material from a supply
5 source at an ambient pressure condition, and an outlet for releasing the
material at
a pressurized condition;
a reactor operating in a pressurized condition for treating the material
with a gaseous reagent, the reactor having an inlet connected tv the outlet of
the
feed system for receiving the material released from the feed system, acrd an
ou~et for releasing the material treated by the reactor .
a conveyor located inside the reactor for conveying the materiat from
the inlet of the reactor to the outlet thereof, so as to treat the material
inside the
reactor operating in a pressurized condition; and
a discharge system for discharging the material treated by the reactor;
the discharge system including:
a chamber operating in a pressurized condition, the chamber
having an inlet connected to the outlet of the reactor for receiving the
material treated by the reactor, and an outlet;
a pump connected to the chamber for pumping liquid into the
chamber so as to put the treated material received from the reactor in
liquid suspension, thereby cooling the treated material with the liquid
and obtaining a corresponding liquid suspended treated material, said
liquid suspended treated material being diachargeable from the
apparatus through the outlet of the chamber; and
a valve provided on the outlet of the chamber, said valve being
operable between a closed configuration for preventing discharging of
the liquid suspended treated material from the chamber and an opened
configuration for allowing discharging of the liquid suspended treated
material from the chamber.
'AMENDED SHEET'
Emp f . ze i t : 09/06/2004 17 : 22 .w . . . ~ .. "", ,. " , .-: 425 P .011
(~g Q6-~~Q~l, = CA 02484850 2004-11-05 CA0300642'
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~,,_ . .. ... .
s
According tv yet another aspect of the present invention, there is also
provided a method for trea~ng solid lignocellulose material, the method
comprising
the Steps of: '
a) feeding the material under a pressurised wndition into a reactor;
b) conveying khe material under a pressurized condition insidie the
reactor along the same for treating said material;
c). transferring the material treated by the reactor int4 a chamber. while
substantially maintaining the pressurized condition of the reactor;
d) pumping liquid into the chamber so as to cool the material' with the
' 14 liquid and obtain a liquid suspended treated material in the chamber;
and
e) discharging the liquid suspended treated material from the chamber;
into an ambient pressure condition.
Preferably, step b) further comprises the step of injecting a gaseous
reagent into the reactor for treating the material.
Preferably also, step e) comprises the steps of:
i) measuring parameters of the liquid suspended treated material present
in the chamber; and
ii) discharging the liquid suspended treated material. from the chamber
r~
when the parameters measured in step i) con-espvnd to predetermined
threshold values. _ ;-.
Preferably, the parameters are selected from the group of level,
temperature, and degree of suspension. ,
preferably also, step a) may comprise the step of impregnating the
material with at least one reagent.
as
The objects, advantages and other features of the present irtventivi~ will
become more apparent upon reading of the following non-restrictive description
of ~~
AMENDED SHEET'
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Og ~~~r~a~~ ' CA 02484850 2004-11-05 ~ ~AQ3Q(~~4~
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6a
preferred embodiments thereof, given for the purpose of exempl~catiQn Only
with
reference to the accompanying drawings.
Brief descril~tivn of the drawings:
Figure 1 is a schematic representation of an apparatus far treating
lignocelluiose material according to a first preferred embodiment of the
invention. ~'
Figure 2 is a schematic representation of an apparatus for treating
1a lignocellulose material according to a second preferred embodiment of the
invention.
20
30
AMENDED SHEET'
Em~f .ze i t : 09~06/~004 17: ~3 " ~ ., .. 425 P .013
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7
Figure 3 is a schematic representation of the discharge system of the
apparatus shown in Figure 2, said discharge system being shown cooperating
with
a control system.
Figure 4 is an enlarged view of the chamber of the discharge system
shown in Figure 3, said chamber being shown provided with a level indicator.
Detailed description of preferred embodiments of the invention:
In the following description, the same numerical references refer to
similar elements. The embodiments shown in the figures are preferred.
In the context of the present description, the expression "lignocellulose
material" includes various types of materials, such as fibrous material,
particulate
material, cellulosic material, and the like. For this reason, the expression
"lignocellulose" and/or other substantially related expressions should not be
taken
as to limit the scope of the present invention and includes all other kinds of
materials or items with which the present invention may be used and could be
useful, as apparent to a person skilled in the art.
Moreover, in the context of the present description, the expressions
"apparatus" and "system", "reactor" and "vessel", "water" and "liquid", as
well as
any other equivalent expressions and/or compound words thereof, may be used
interchangeably. The same applies for any other mutually equivalent
expressions,
such as "treating" and "cooking" for example, as apparent to a person skilled
in the
art.
In addition, although the preferred embodiment of the present invention
as illustrated in the accompanying drawings comprises various components such
as a control system, level indicators, a timer, thermocouples, ball valves, a
screw
conveyor, a pump, etc., and although the preferred embodiment of the apparatus
1
and corresponding parts of the present invention as shown consists of certain
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geometrical configurations as explained and illustrated herein, not all of
these
components and geometries are essential to the invention and thus should not
be
taken in their restrictive sense, i.e. should not be taken as to limit the
scope of the
present invention. It is to be understood, as also apparent to a person
skilled in the
art, that other suitable components and cooperations thereinbetween, as well
as
other suitable geometrical configurations may be used for apparatus 1
according
to the present invention, as will be briefly explained herein and as can be
easily
inferred herefrom, without departing from the scope of the invention.
Broadly described, the apparatus 1 according to the present invention,
as exemplified in the accompanying drawings, is an apparatus 1 for treating
lignocellulose material, fibrous material, particulate material, and the like,
which
may be operated continuously or intermittently at frequent intervals. The
material
is preferably treated inside a reactor 5 by means of steam, under pressurized
conditions, and at predetermined temperature levels. The material treated by
the
reactor 5 is then transferred into a discharge system 9, where it is cooled,
and put
into liquid suspension in an aqueous environment preferably, so as to
subsequently be discharged into ambient pressure conditions without explosive
depressurization, in order to maintain the integrity of the treated material,
and thus
prevent deterioration (bursting of cells, defiberizing, etc.) thereof.
The apparatus 1 .may be used for different applications, such as
cooking, mixing, and the like, whether operated continuously or intermittently
at
different intervals, as will be explained hereinbelow, and for treating under
pressurized conditions a variety of materials such as lignocellulose material,
fibrous material, particulate material, cellulosic material, and the like.
Indeed,
examples of cellulosic materials are poplar wood chips, straw, bagasse or the
like
material, which could be converted into nutritious fodder for example. As is
known
in the art, the lignocelluiose material is of the type which may include a
plurality of
different lengths of the particles, e.g. from a complete length of straw
stalks or
stems to chopped straw, the material including wood chips but also different
sorts
of sawmill rejects, it being understood by a person skilled in the art that,
for
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9
example, sawdust of so-called saw-flour type is in fact composed of minute
panicles of wood whose fibers are too short to fall within the scope of the
term of
"fibrous" material. Hence, several other materials may be used with the
apparatus
1 according to the present invention, such as wood chips, fibers of various
origins
and dimensions, sawdust, flours, powders, fragments of organic products, etc.,
as
apparent to a person skilled in the an. The apparatus 1 according to the
present
invention comprises a discharge system 9 which is devised to discharge liquid
suspended treated material 15 wifihout vaporization of the liquid and without
bursting of the solid, as explained hereinbelow.
As better shown in Figures 1 and ~, the apparatus 1 for treating material
according to the present invention preferably comprises a feed system 3, a
reactor
5, a conveyor 7 and a discharge system 9. The feed system 3 has an inlet for
receiving the material from a supply source and an outlet for releasing the
material. The reactor 5 is used for treating the material, and has an inlet
connected
to the outlet of the feed system 3 for receiving the material released from
the feed
system 3, and an outlet for releasing the material treated by the reactor 5.
The
conveyor 7 is preferably located inside the reactor 5 for conveying the
material
from the inlet of the reactor 5 to the outlet thereof. The discharge system 9
is used
for suitably discharging the material from the apparatus 1. The discharge
system 9
comprises a chamber 11 having an inlet connected fio the outlet of the reactor
5 for
receiving the material treated by the reactor 5, and an outlet, as better
shown in
Figure 3. The discharge system 9 also comprises a pump 13 connected to the
chamber 11 for pumping liquid info the chamber 11 so as to put the treated
material received from the reactor 5 in liquid suspension, thereby obtaining a
liquid
suspended treated material 15, said liquid suspended treated material 15 being
dischargeable from the apparatus 1 through the outlet of the chamber 11, as
can
be easily understood when referring to Figures 2-4.
The feed system 3 is preferably intended to receive raw material to be
treated at ambient pressure conditions into a feeding hopper 17. As better
shown
in Figure 2, the feed system 3 preferably comprises first and second valves
19, 21,
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and a chamber 23 located thereinbetween. Raw material to be treated by the
apparatus 1 is preferably inserted into the feed system 3 as follows. Firstly,
the
first and second valves 19, 21 are originally closed, and are preferably
devised to
never be opened at the same time. The first valve 19 is then opened, so as to
5 allow raw material from the hopper 17 to be inserted into the chamber 23.
Subsequently, the first valve 19 is closed, and the material located inside
the
chamber 23 is subjected to pressurized conditions similar to or substantially
equal
to that of the pressure conditions inside the reactor 5. Upon reaching
suitable
pressurized conditians, as apparent to a person skilled in the art, the second
valve
10 21 is opened so as to allow the material to be treated, now under
pressurized
conditions, to suitably enter into the inlet of the reactor 5, as better shown
in Figure
2. The second valve 21 is then closed, and the cycle of the feed system 3 for
feeding material to be treated into the reactor 5 is repeated, as can be
easily
understood. It is worth mentioning that other suitable types of feed systems 3
may
be used according to the present invention, whether they be operated
continuously, or intermittently, so long as they enable the raw material to be
treated to be inserted into the reactor 5 under pressurized conditions similar
to or
substantially equal to those of the reactor 5, so as to enable a proper
insertion of
the material into the reactor 5, white also ensuring to minimize or prevent
the loss
of pressure, as apparent to a person skilled in the art. The above-mentioned
chamber 23 of the feed system 3 located between the first and second valves
19,
21 preferably comprise suitable inlets connected thereto for pressurizing the
chamber 23, and/or injecting liquid and/or gaseous reagents therein, as
apparent
to a person skilled in the art. Preferably also, the first and second valves
19, 21
are ball valves, although other types of valves 19, 21 may be used, as
apparent to
a person skilled in the art. Preferably also, the various components of the
feed
system 3 are suitably insulated from ambient conditions, as also apparent to a
person skilled in the art.
As can be easily understood from the aforementioned, the opening and
closing of the valves 19, 21 is preferably synchronized so as fio enable to
feed the
reactor 5 with material to be treated at the same pressure than that of the
reactor 5
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by isolating the same from the ambient conditions of the raw material in the
hopper
17. As aforementioned, other feed systems 3, which are well known in the art
and
widely used, such as the one described in the Canadian patent no. 1,070,037,
which employs namely a system of reciprocating pistons, could be used.
However,
the latter requires the compaction of the material to be treated, in the form
of a
"plug", and this way of feeding is, namely, fairly expensive and energy
consuming.
Thus, fihe above-discussed embodiment of feed system 3 is preferably used with
the apparatus 1 according to the present invention, although other suitable
feed
systems 3, whether operated continuously or intermittently, may be employed,
as
apparent to a person skilled in the art. Indeed, the present teed system 3, as
above-discussed, does not require to compact the material to be treated into a
"plug", which is advantageous with respect to the above-mentioned prior art
feed
system. Furthermore, the feed system 3 is preferably devised so as to
introduce
the material to be treated into the reactor 5, without depressurizing the
same.
As better shown in Figure 2, the apparatus 1 also comprises a reactor 5
in which the material is treated, in various ways, either by hydrolysis,
cooking, and
the like. Typically, the treatment of the material inside the reactor 5 is
carried-out
by means of gaseous reagent(s), such as steam fior example, which is injected
into
the reactor 5, under pressurized conditions, and at suitable temperature
levels, for
adequately treating the material depending on the nature thereof. Gaseous
reagents other than steam may be used according to the present invention, as
apparent to a person skilled in the art.
Preferably, the reactor 5 comprises a vessel 25, which is preferably
cylindrical, and supported by suitable supporting means, as better shown in
Figures 1 and 2. The reactor 5 also comprises a conveyor 7 located inside the
reactor 5 for conveying the mafierial from the inlet of the reactor 5 to the
outlet
thereof. The conveyor 7 preferably comprises a screw conveyor 7 having a
longitudinal shaft operated by a motor, preferably intended to rotate the same
at
variable speeds, depending on the conveying rate which is desired. The
difFerent
parameters of the screw conveyor 7, such as the geometrical disposition of the
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12
helix, dimensions thereof, and the like, are preferably selected depending on
the
nature of the material to be treated, and the particular applications for
which the
apparatus 1 is intended, as apparent to a person skilled in the art. As better
shown
in Figures 1 and 2, the cylindrical vessel 25 is preferably disposed
horizontally, and
preferably is provided with several injection inlets for injecting gaseous
reagents
into the vessel 25, such as steam under pressure for example, although other
suitable reagents may be used once again depending on the nature of the
material
to be treated and the particular applications for which the apparatus 1 is
used.
Preferably also, the reactor 5 is provided with various sensors disposed
therealong
for sensing temperature and pressure inside the vessel 25.
As aforementioned, the vessel 25 of the reactor 5 is preferably a
cylindrical tube, which is preferably disposed horizontally, in order to,
namely,
facilitate the conveying of the product to be treated along the reactor 5. As
aforementioned, the conveyor 7 preferably consists of an endless screw having
a
shaft rotatable about a fixed structure, for ensuring fihe transfer of the
material to
be treated inside the tube at a given speed enabling to adjustably control the
time
of treatment, i.e. the time of "cooking" of the material. The screw conveyor 7
may
be rotated at different speeds, with fihe variable speed motor, so as to
expose the
material to be treated inside the reactor 5 at different cooking times, if
desired. The
screw conveyor 7 is preferably mounted at extremities of the fixed structure
of the
reactor 5, and said reactor 5 is preferably well insulated from its
environment in
order to avoid losses of heat and the condensation of a portion of the vapor
injected therein.
As better shown in Figure 2, the end portion of the conveyor 7
preferably has a helix portion contrary to the conveying portion to ensure
that the
material treated in the reactor 5 which ends at the extremity of the reactor 5
is
suitably biased into the discharge system 9 via the inlet of the discharge
chamber
11.
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As also shown in Figure 2, the discharge system 9 is preferably located
at the end of the reactor 5, and comprises a chamber 11 which is preferably a
substantially vertical tube having an inlet, preferably tapered, which is
connected
to the outlet of the reactor 5 for receiving the material treated by the
reactor 5, and
an outlet. This chamber 11 is mainly used for cooling and putting in liquid
suspension the material treated by the reactor 5 so as to ensure proper
discharging conditions prior to discharging the treated material into ambient
conditions. Indeed, as better shown in Figure 3, the outlet of the chamber 11
is
preferably provided with a discharging valve 27 which enables to carry out the
discharging of the treated product, after being cooled, while being kept under
pressure, into a suitable receptor at atmospheric pressure. Because the
treated
material is in liquid suspension and has been substantially cooled, the
resulting
temperature gradient when the liquid suspended treafied material 15 is
discharged
into ambient condition is therefore subsfiantially reduced, and thus the
integrity of
the material is maintained, and said liquid suspended treated material 15 may
be
further processed, filtered, and/or the like, so as to obtain a desired
product with
the treated material.
As aforementioned, the outlet of the discharge chamber 11 is provided
with a valve 27, said valve 27 being operable between a closed configuration
for
preventing discharge of the liquid suspended treated material 15 from the
chamber
11 and an opened configuration for allowing discharging of the liquid
suspended
treated material 15 from the chamber 11. Due to the pressurized conditions
inside
the reactor 5 and the discharge chamber 11, the valve 27 is preferably
selected to
be operable between the opened and closed configurations, in a rapid manner,
as
apparent to a person skilled in the art. Preferably, a ball valve 27 is used,
although
other types of suitable valves 27 may also be used according to the present
invention, as also apparent to a person skilled in the art.
According to the preferred embodiment of the invention, and as better
shown in Figure 3, the chamber 11 preferably comprises a first sensor 29,
typically
known as the "low level detector", for detecting when the liquid suspended
treated
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material 15 inside the chamber 11 is at a first level, i.e. the low level.
Preferably
also, the chamber 11 comprises a second sensor 31, known as the "high level
detector", for detecting when the liquid suspended treated material 15 inside
the
chamber 11 is at a second level, i.e. the high level. As better shown in
Figures 3
and 4, the second level (high Ieve1) is located at a higher level than the
first level
(low level).
As can be easily understood, the pump 13 used for pumping liquid into
the chamber 11 is preferably selected so as to have a positive displacement
for
injecting the liquid under pressure capable of overcoming the pressure inside
the
chamber 11, which is typically similar or substantially equal to that of the
reactor 5,
and thus enable to put the treated material conveyed into the chamber 11 in
liquid
suspension, so as to substantially cool-off the same due to the interaction
with the
liquid, and also enable it to be more easily dischargeable via the outlet of
the
chamber 11, thereby avoiding substantial pressure losses in the system.
As better shown in Figure 3, the apparatus 1 preferably comprises a
control system 33 operatively connected to the valve 27, for operating the
same in
the opened configuration upon of a signal from the second sensor 31 when the
liquid suspended treated material 15 inside the chamber 11 reaches fihe second
level, and for operating the valve 27 in the closed configuration upon
reception of a
signal from the first sensor 29 when the liquid suspended treated material 15
inside the chamber 11 falls to the first level.
Indeed, the opening and closing of the discharge valve 27 is carried out
according to predetermined conditions of the liquid suspended treated material
15
inside the chamber 11 for proper discharging thereof. The liquid suspended
treated material 15 is preferably discharged from the chamber 11 towards a
receptor which is at atmospheric pressure until the low level detector 29 of
the
chamber 11 has been triggered, or after a certain predetermined time, and the
discharge valve 27 is then closed so as to repeat the discharging cycle.
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As can be easily understood, the flow rate of the pump 13 is adjusted
so as to enable the formation of a transferable liquid suspended treated
material
15, in order also to enable suitable cooling of the treated material inside
the
chamber 11, and also in order to ensure the discharging of the treated
material
5 from the system, without vaporization of the water nor bursting of the solid
of the
liquid suspended treated material 15.
The operation of the discharge valve 27 of the discharge system 9 may
be carried out in various other suitable ways. Indeed, the control system 33
may
10 be provided with a timer so as to alternatively operate the valve 27 in the
closed
and opened configurations during predetermined time intervals, as apparent to
a
person skilled in the art.
Moreover, the chamber 11 may be provided with at least one
15 temperature sensor 35 for measuring the temperature of the liquid suspended
treated material 15 inside the chamber 11, and the control system 33 may be
devised so as to alternatively operate the valve 27 in the opened and closed
configurations upon reception of corresponding signals from the at least one
temperature sensor 35 according to predetermined temperafiure values measured
by said at least one temperature sensor 35. Preferably, a plurality of
temperature
sensors 35 are disposed along the chamber 11 for measuring the temperature of
the liquid suspended treated material 15 at different levels inside the
chamber 11.
Moreover, a plurality of temperature and level sensors 35, 29, 31 are
preferably disposed along the length of the chamber 11, and one or several
injection lines for pumping liquid into the chamber 11 and cooling the treated
material may be installed strategically along the chamber 11, as also apparent
to a
person skilled in the art.
The various sensors, such as thermocouples for example, disposed
along the chamber 11 enable to namely, verify, if the temperature gradient of
the
cycle needs to be corrected by means of the debit water injected into the
chamber
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11 by the pump 13 andlor if the frequency of opening and closing of the
discharging valve 27 needs to be adjusted. As aforementioned, the lateral or
inferior inlets for injecting liquid, preferably copied pressurized water,
into the
chamber 11, is carried out with a pump 13 with positive displacement able to
overcome the pressurized conditions inside the chamber 11, as apparent to a
person skilled in the art. The various components of the discharge system 9,
such
as the Level detectors 29, 31, the temperature sensors 35, the pump 13, the
valve
27, etc., are all preferably connected to the control system 33 which operates
and
coordinates the discharge valve 27 (and pump 13) accordingly, as apparent to a
person skilled in the art. As may now be better appreciated, and as a result
of the
above-discussed, when the outlet of the chamber 11 is opened, the liquid
suspended treated material 15 may be discharged under desired and adjusted
conditions, into a receptor, without explosive depressurization due to high
temperature gradient.
Indeed, the different components of the discharge system 9, such as
the level detectors 29, 31, the temperature gages 35, the control system 33,
the
pump 13, the valve 27, and the like, are preferably intended and operated so
as to
ensure that the liquid suspended treated material 15 discharged from the
chamber
11 is never depressurized violently because a minimum temperature level is
always ensured which will thus avoid the bursting of the cells of the treated
material. Furthermore, the different components of the discharge system 9, and
the injecting of liquid via the pump 13, are preferably selected so as to
ensure that
the liquid suspended treated material 15 is at a suitable temperature, so as
to
avoid an abrupt evaporation of the treated material which would risk a
cellular
bursting of the treated material.
Following is a typical example of raw material treated by the apparatus
1 according to the present invention. Indeed, material to be treated, such as
cellulosic fibers, are preferably introduced in a humid configuration, for
example at
about 40 % in weight, into the feed system 3. The material is then fed into
the
reactor 5, which preferably contains steam at about 220° C and operates
at about
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350 psi, fihese fibers being transported inside the reactor 5 by the
firansferring
conveyor 7, during a predetermined time, which is preferably calculated
according
to the speed of rotation of the endless screw. At the end of the reactor 5,
the helix
portion of the reactor 5 changes in direction over a predetermined length in
order
to avoid any accumulation of the product at the end of the reactor 5 which
would
lead to a excessive exposure fo cooking and also give rise to degradation
products
which could contaminate the reactor 5. At the same level, there is found the
inlet to
the chamber 11 of the discharge system 9, said chamber 11 intended to cool and
put the treafied mafierial in liquid suspension. The treafied material falls
into this
chamber 11 by means of the converging helix portions of the conveyor 7 and is
fed
by water at a certain temperature, for example at 10° C. The water is
inserted into
the chamber 11 via a pump 13 with positive displacement which can overcome the
pressure of the reactor 5 and corresponding chamber 11, which is typically
located
at around 400 psi. The treated product, enters thus in contact with the water,
and
forms a suspension which is cooled in the chamber 11. As a liquid is injected
into
the chamber 11, the level of liquid suspended treafied material 15 raises, and
when
said level reaches the high level detected by the high level detector 31, the
latter
sends a signal to the control system 33 which activates the opening of the
discharge valve 27 located at the outlet of the chamber 11.
Thus, as can be easily appreciated, from the aforementioned example,
the apparatus 1 according to the present invention enables to introduce
material to
be treated into the reactor 5, in a humid state, via the feed system 3,
without
loosing substantial pressure, at about 200° C for example, and then to
have it
treated (i.e. "cooked") at about 200° C, at a pressure of about 350 psi
with steam
for example, and then, for it to be transferred into an aqueous environment
while
keeping it in pressure conditions of aboufi 350 ,psi and cooling ifi to about
80° C, or
less, and have a discharging thereof via the discharge valve 27 towards a
receptor
at atmospheric pressure and at a temperature of about 80° C or less, so
as to
have a temperature gradient between the discharging treated material and that
of
the ambient environment which is such that the treated material discharged is
not
subject fio explosive depressurization.
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It is to be understood fihafi several modifications could be made to the
present apparatus 1 according to the present invention without departing from
the
scope of the present invention. Indeed, as aforementioned, the level detectors
29,
31 of the chamber 11 of the discharge system 9 may come in different forms, as
apparent to a person skilled in the art, such as a capacitance level, a
conductive
level switch, a float level, ultrasonic means, microwave means, differential
pressure transmitter, vibrating blade level, consistency transmitter, and the
like.
Furthermore, in order to regulate or depressurize the liquid suspended
treated material 15 discharged from the system, various types of valves 27,
such
as bail valves 27 for example, or any other types of suitable valves wifih
rapid
acfiion, as apparenfi to a person skilled in the art, may be used, as well as
a piping
of smaller diameter in order to create a loss of pressure, as well as a rotary
valve,
or a pump coupled to an hydraulic, mechanical or magnetic brake, so as to
evacuate the liquid similarly to what is possible with a rotary valve, for
example, as
also apparent to a person skilled in the arfi.
In regards to the discharge system 9, it is worth menfiioning fihafi the
latter may be provided with an activafior connected to fihe control system 33
for
selectively activating the pump 13, for enabling to stop the pump 13 during
the
discharging phase, for example. Moreover, the discharge sysfiem 9 may be
provided with a timer, so as to, for example, substitute the low level
deflector 29 by
activating the discharge valve 27, and thus assuring the same funcfiion,
during
operation, while being less expensive. Moreover, as aforementioned, the
discharge system 9 may be provided with a plurality of temperafiure sensors
35,
which would enable to control more precisely the temperature of the liquid
suspended treated material 15 inside the chamber 11. In addition, a plurality
of
inlets may be provided along the chamber 11 for injecting liquid at various
locations, which would enable to equilibrate the temperatures of the liquid
suspended treated material 15 inside the chamber 11 and also facilitate the
transferring thereof towards a receptor.
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The apparafius 1 and corresponding parts are preferably made of
substanfiially rigid materials, such as metallic materials (stainless steel,
etc.),
hardened polymers, composite materials, andlor the like, so as to ensure a
proper
operation thereof depending on the particular applications for which the
apparatus
1 is intended and fibs different paramefiers in cause, as apparent to a person
skilled in the art.
According to another aspect of the present invention, fibers is provided
a method for fireating material, such as lignocellulose material, fibrous
material,
particulate material, cellulosic material, and the like. The method comprising
the
steps of a) feeding the material infio a reactor 5; b) conveying the material
inside
the reactor 5 along the same for treafiing said material; c) transferring the
material
fireated by the reactor 5 into a chamber 11; d) pumping liquid into the
chamber 11
so as to obtain a liquid suspended treated material 15 in the chamber 11; and
e)
discharging the liquid suspended treated material 15 from the chamber 11.
Preferably, sfiep b) further comprises fibs sfiep of injecting a gaseous
reagent into the reactor 5 for treating the material.
Preferably also, step e) comprises the steps of i) measuring parameters
of the liquid suspended treated material 15 present in the chamber 17; and ii)
discharging the liquid suspended treated material 15 from the chamber 11 when
the parameters measured in sfiep i) correspond to predetermined threshold
values.
Preferably also, the paramefiers are selected from the group of level,
temperafiure,
and degree of liquid suspension.
Preferably also, step a) may comprise the step of impregnating fibs
material with at leasfi one reagent.
As may now be better appreciated, the present invention is a
substantial improvement and presenfis several advantages over devices and/or
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methods known on the prior art, in that, as aforementioned, it a) limits the
losses of
pressure and/or gaseous reagent(s); b) maintains a greater stability of the
reactor
5 by avoiding the exiting of gaseous reagents) through the discharge valve 27;
c)
avoids the abrupt discharging of the treated material thanks to the
substantial
5 cooling and Liquid suspending of the treated material in the discharge
system 9; d)
avoids the displacement by flow back of the product into the reactor 5, which
is
typical to abrupt discharging, this would indeed change the cooking time for a
portion of the product and thus lead to an non-homogeneous product; e)
prevents
the bursting of the cells of the treated material; f) limits at a minimum the
losses of
10 volatiles and the losses of solids during the discharging; and g) avoids
the violent
impacting afi the discharging stage, thereby avoiding the deterioration of
parts and
components of the system.
The present invention is also advantageous in that, as may now be
15 easily understood, the components and synchronization thereof enable the
present apparatus 1 to control the discharging of Treated material treated by
means of gaseous reagents under pressure, by a transfer of these treated
materials info an aqueous environment which is pressurized, and then by
controllably discharging the fatter into atmospheric conditions in an aqueous
20 environment without an abrupfi depressurization of the water contained in
the liquid
suspended treated material 15, out of the apparatus 1. Furthermore, the
present
invention is also a substantial improvement over the prior art in that as can
now be
easily understood, the present apparatus 1 namely enables to not only treat a
solid
in the presence of high pressure steam, but also enables to cool off the
treated
material resulting therefrom in order to suitably enable to discharge the same
without explosive depressurization, and thus maintaining the structural
integrity
and characteristics of the treated material, which is very desirable.
Of course, numerous modifications could be made to the above-
described embodiments without departing the scope of the invention, as defined
in
the appended claims.
