Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02681816 2009-10-07
METHOD OF EXTRACTING ESSENTIAL OIL FROM BIOMASS
WASTES AND A DEVICE THEREOF
BACKGROUND OF THE INVENTION
a) Field of the Invention
The present invention relates to a method of extracting essential oil
from biomass wastes and a device thereof, and more particularly to a
processing method which executes dry distillation to biomass wastes
such as wood wastes, wood chips or other plants in an air-tight reaction
vessel under an oxygen-free condition, in order to acquire high quality
essential oil and residuals which are activated carbons as by-products;
and a system device which utilizes this processing method.
b) Description of the Prior Art
Ordinary so-called essential oil is primarily plant-type essential oil
which is extracted from branches, leaves, roots, stems, skins, chips,
fruits, buds and resins of the plants, is usually in a liquid state and is
lighter than water that the essential oil is different from grease. An
ingredient of the essential oil generally refers to hydrocarbon in a form of
(C5H8)n, but primarily terpenes and derivatives like aromatic
hydrocarbons, alcohols, aldehydes and ketones having C10H16, C15H24
and C20H32. There are usually three methods to extract the essential oil:
(1) the steam distillation method (2) the press method and (3) the solvent
method; and the most commonly used one is the steam distillation
method.
As being provided with strong adsorption, deodorization,
decolorizing and filtering capabilities to inorganic or organic materials or
colloidal particles in solution, activated carbons have been widely
applied in food product, medicine, grease, gasoline and water
processing industries, and demands are increasing year by year. An
ordinary method for producing the activated carbons includes using
wood, wood chips, coconut shells, bagasse, coal and peat as raw
materials, which are carbonized and then activated to form the activated
carbons. The activation methods include (1) the steam activation
method (2) the chemical activation method and (3) other methods. In
the steam activation method, the carbonized raw materials are smashed
and then are activated in a boiler with superheated steam at temperature
of more than 800 C. In the typical chemical activation method, the
smashed raw materials are submerged in solution of zinc chloride and
then are activated along with calcinations and carbonization; whereas
chemicals are removed by washing with water after the activation. As
for other methods, the raw materials are filled with inert gas such as air,
carbon dioxide or nitrogen, and then are calcinated and activated.
1
CA 02681816 2009-10-07
The aforementioned production methods for extracting the essential
oil and the activated carbons utilize two different equipment and two
different manufacturing processes to implement independently. Hence,
very large equipment space will be needed, manufacturing time will be
long, much energy will be wasted and more operation personnel will be
required, thereby being very difficult to comply with economic benefits.
The Taiwanese New Utility Patent Publication No. 477239 discloses
a simple essential oil extraction device which is a small-scaled easy
assembling device utilizing the steam distillation method to extract the
essential oil from aromatic flowers, is suitable for laboratory use or
personal DIY use and does not aim for industrial mass production.
On the other hand, the Taiwanese New Utility Patent No. M266969
discloses an improved structure of an essential oil extraction device.
This device is basically about the same as that disclosed by the
aforementioned New Utility Patent Publication No. 477239. The only
differences are that an upper part of an inner tube of a condensing tube
is formed with a steam chamber of larger diameter, a lower part is
formed with a oil gathering chamber of reduced diameter, and a lower
end of this inner tube is connected with an essential oil reverse tube
which is connected to a gas pipe coming from a flask.
The Taiwanese New Utility Patent Publication No. 481045 discloses
a movable essential oil extraction device. This device still uses the
steam distillation method as the aforementioned two patents. However,
the device is middle-scaled and is movable.
Besides, the Taiwanese Invention Patent Publication No. 517078
also discloses a method which uses waste rubber to produce gasoline,
diesel oil and carbon black. As disclosed by the aforementioned Patent
Publication No. 462984, the method utilizes very large factory equipment
and a complicated operating system to refine waste tires into gasoline,
3o diesel oil and carbon black by thermal pyrolysis cracking and catalytic
cracking.
Moreover, the Taiwanese Invention Publication No. 462984
discloses a method and a device for continuously recycling and refining
waste tires into activated carbons. This invention is suitable to process
tires in a large scale to acquire combustible fuel, combustible gas and
carbon black. The combustible fuel and the combustible gas provide
for the fuels used in a thermal pyrolysis cracking furnace and an
activation furnace, and the carbon black is removed with impurities,
smashed and guided into the activation furnace to be activated into
activated carbons in grains.
The latter two patents described above contribute a certain degree
to resource recycling and environmental protection; yet, equipment cost
is huge and they cannot apply to the production of essential oil.
Furthermore, the Taiwanese Invention Patent Publication No. 2008
2
CA 02681816 2009-10-07
19525 discloses a production system and method for biomass energy
activated carbons, wherein processed raw materials can be carbonized
and activated as the activated carbons in the system. This invention is
featured by that waste heat generated by a carbonization-activation
furnace is used to heat up a boiler producing high-temperature steam
which is guided into the carbonization-activation furnace to activate the
carbonized raw materials.
However, none of the aforementioned prior arts discloses a
technology that in a same time when a single system extracts the
essential oil from the biomass materials, the remaining solid-state
carbonized materials can be activated to acquire the activated carbons,
nor discloses operating conditions at which various temperature and
pressure are controlled during the thermal pyrolysis cracking process.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a method of
extracting essential oil from biomass wastes. The method particularly
puts plant-type biomass wastes in an air-tight oxygen-free reaction
vessel for dry distillation (i.e., thermal pyrolysis cracking) to acquire
plant-type oil or essential oil, and in a same time, to get activated
carbons as by-products.
A second object of the present invention is to provide a method by
which essential oil can be extracted from biomass wastes and activated
carbons can be obtained at a same time. In a manufacturing process,
temperature and pressure in a reaction vessel are controlled in phases,
and air is sucked out in a short time by a high-speed suction pump
depending upon internal pressure and distilled substance in the reaction
vessel, so as to maintain at low pressure and prevent the distilled
substance from staying in the reaction vessel for too long that the
distilled substance is scorched excessively. Therefore, a processing
time can be shortened, essential oil of high quality and high yield and
activated carbons as by-products can be acquired.
A third object of the present invention is to provide a device which
implements the aforementioned method of extracting essential oil from
biomass wastes. The device includes an air-tight reaction vessel
having a lock-type inner vessel, which is used to heat up biomass raw
materials indirectly to be thermally disintegrated, a condenser which
condenses thermally disintegrated and distilled gas as liquid, a
separation tank which separates condensed liquid into water and oil, and
a suction pump which is provided at an outlet port of the separation tank.
A fourth object of the present invention is to provide a device which
implements the aforementioned method, wherein the suction pump
which is located at the outlet port of the separation tank is a suction
3
CA 02681816 2009-10-07
pump with a changeable flow rate and a changeable rotation speed,
such that when internal pressure of the reaction vessel rises up to
exceed pre-determined pressure, a suction rate will be increased quickly,
so as to reduce the internal pressure in a short time to keep at low
pressure, thereby promoting evaporation and avoiding distilled
substance to be staying in the reaction vessel for too long that the
distilled substance is scorched excessively.
A fifth object of the present invention is to provide a device which
implements the aforementioned method, wherein an interior of the
separation tank is provided with an ultrasonic generator to facilitate tars
to be re-disintegrated, thereby improving quality and capacity of oil
products.
A sixth object of the present invention is to provide a device which
implements the aforementioned method, wherein an exhaust pipe of the
separation tank can be further connected with a second condenser and a
mixing tank if necessary, such that after non-liquefied gas is further
condensed at lower temperature as oil, the oil is mixed with the oil which
is guided into the mixing tank from the separation tank, thereby
increasing an extraction rate.
To enable a further understanding of the said objectives and the
technological methods of the invention herein, the brief description of the
drawings below is followed by the detailed description of the preferred
embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a schematic view of components of a first embodiment of a
system which extracts essential oil from biomass wastes, according to
the present invention.
FIG. 2 shows a schematic view of components of a second embodiment
of an essential oil extraction system, according to the present invention.
FIG. 3 shows a schematic view of components of a third embodiment of
an essential oil extraction system, according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the drawings, FIG. 1 shows a schematic view of components of a
first embodiment of a system which extracts essential oil from biomass
wastes, according to the present invention; FIG. 2 shows a schematic
view of components of a second embodiment of an essential oil
extraction system, according to the present invention; and FIG. 3 shows
4
CA 02681816 2009-10-07
a schematic view of components of a third embodiment of an essential
oil extraction system, according to the present invention.
A first embodiment of an essential oil extraction system as shown in
FIG. 1 comprises a reaction vessel 1, a condenser 2, a water-oil
separation tank 3, a suction pump 4 and a control booth 5 which are
orderly provided downstream the reaction vessel 1 according to piping.
The reaction vessel 1 includes an exterior vessel 11 which is
surrounded by an electro-thermal device 14 and a thermal insulation
humectant 15, a dismountable inner vessel 12 and an air-tight cover 13
which can be tightly covered on an opening of the exterior vessel 11. A
side wall at an upper part of the exterior vessel 11 is provided with a gas
outlet 16 from which a gas pipe P is connected to an inlet port of the
condenser 2. The cover 13 is provided with a safety valve 17 and a
pressure gage 18.
The condenser 2 is provided with a sealed tank 21 and a helical or
devious inner tube 22 which is emplaced inside the sealed tank 21. An
end of the tank 21 is connected to an outlet port of the gas pipe P, and
this outlet port is preferably formed with a gas gathering chamber 23 of
large diameter. An end of the gas gathering chamber 23 is connected
to an end of the aforementioned inner tube 22, and the other end of the
inner tube 22 is connected to the water-oil separation tank 3. In
addition, an outer peripheral wall of the tank 21 is formed with a water
jacket 24 and is provided with a cooling water (or coolant) inlet 25 and
outlet 26 to introduce and discharge the cooling water or coolant. The
condenser 2 is not limited to the type used in the present embodiment
and any suitable conventional condenser can be used, including the
condenser which is not provided with the gas gathering chamber 23.
The water-oil separation tank 3 is used to separate condensate of
the condenser 2 into water and oil, and an interior of the tank 3 is
provided with a baffle 31 to divide the tank 3 into a liquid gathering
chamber 32 and an overflow chamber 33. After the condensate has
entered into the liquid gathering chamber 32, oil, which is provided with
lighter specific weight and floats on top of water, overflows from the liquid
gathering chamber 32 into the overflow chamber 33; whereas,
non-liquefied gas, which is located above a liquid surface, is sucked out
by the suction pump 4 to be discharged into atmosphere through an
exhaust pipe P1. In order to prevent hot gas or smell from polluting air,
it is preferably to guide gas into a water-sealed tank 6 for reducing
temperature and deodorizing prior to be discharged outside.
The control booth 5 is located in the system at a place for easy
monitoring and controlling. This control booth 5 is provided with a
power switch, a pressure gage, a temperature gage, buttons used for
adjusting and controlling internal pressure and temperature of the
reaction vessel 1, and a caution light or an alarm for an abnormal
5
CA 02681816 2009-10-07
condition. The control booth 5 is connected to a pressure transducer
51, a temperature transducer 52, the electro-thermal device 14 and the
suction pump 4 by wires, and is of course also provided with power lines
L for connection to a power source.
Hereinafter a method using the aforementioned system to extract
the essential oil from the biomass wastes is described.
First, raw waste materials M, such as cypress residual branches or
stems, which are cleaned, dried, smashed or chopped properly, are put
into the inner vessel 12 of the reaction vessel 1, and then the reaction
vessel 1 is covered tightly by the cover 13 to keep air-tight inside the
reaction vessel 1. Next, the suction pump 4 is operated to suck air out
of the reaction vessel 1, decreasing internal pressure of the reaction
vessel 1 to 0.5-0.8kg/cm2, in a low vacuum condition. If necessary,
inert gas like nitrogen can be filled into the reaction vessel 1. Then,
power is activated by the control booth 5 to heat up the electro-thermal
device 14, and temperature inside the reaction vessel 1 is controlled at
150-200 C by a temperature control button. After a while, the raw
materials M inside the reaction vessel 1 will be disintegrated to produce
smoky gas which contains mostly water at 100 C and small part of light
oil. The gas flows into the gas gathering chamber 23 of the condenser
2 through the gas pipe P, and when flowing through the helical inner tube
22, is condensed as liquid by the cooling water in the water jacket 24 and
next flows into the separation tank 3. At this time, when the condensate
which contains mostly water flows into the liquid gathering chamber 32
until a water level exceeds a top end of the baffle 31, oil which is
provided with small specific weight and floats on top of water will
overflow from the liquid gathering chamber 32 to the overflow chamber
33 and be stored in this chamber. When the oil is stored to a certain
quantity, a valve 34 can be opened, allowing the oil to be gathered in an
oil tank 36 through an oil drain pipe 35. The water level of the liquid
gathering chamber 32 is kept at a certain level by a water level gage (not
shown in the drawings) or other means, and excessive water is
discharged outside through a water drain pipe 37.
In the thermal pyrolysis cracking or dry distillation process, when a
large amount of gas is generated inside the reaction vessel 1 that the
internal pressure increases to exceed pre-determined pressure, e.g.,
1.2kg/cm2, which can be identified by the pressure gage and the alarm of
the control booth 5, the suction pump 4 can be controlled automatically
by an electrically controlled loop or computer software (both not shown
in the drawings) connected with the pressure gage or manually by an
operator to rotate in high speed or to increase a flow rate and to suck out
air for a short time, e.g. 1 min. to several minutes, enabling the
pressurized gas to enter in a large quantity into the gas gathering
chamber 23 that the internal pressure can decrease in a short time to
6
CA 02681816 2009-10-07
below 0.8kg/cm2 for example, in order to keep at dry distillation in low
pressure, such that when volatile substance evaporates in lower
temperature, distilled substance can be prevented from staying in the
reaction vessel 1 for too long that the distilled substance is scorched
excessively to result in more heavy tars. When the pressure restores to
the original pre-determined pressure and almost no condensate is
produced continuously or gas discharge is largely reduced, reaction
temperature setting is changed to 250-350 C for example, by the control
booth 5 to implement a second phase of thermal pyrolysis cracking
process, with pressure still being kept at 0.5-0.8kg/cm2. As most water
has evaporated completely in the aforementioned first phase of thermal
pyrolysis cracking process, in this phase, only most high boiling point
essential oil at temperature higher than 250 C will evaporate to gas
under this temperature. After flowing into the condenser 2 through the
gas pipe P and is condensed as liquid, the gas will enter into the
separation tank 3 and overflow to the overflow chamber 33; whereas, the
non-liquefied gas is discharged through the exhaust pipe P1. Under
high temperature, the pressure inside the reaction vessel 1 will still rise
up following the increase of temperature and the generation of a large
quantity of gas. At this time, the suction pump 4 can be controlled
automatically or manually as described above to carry out a high
flow-rate suction operation in a short time, allowing the internal pressure
to drop timely, so as to maintain at a pre-determined low pressure state
of 0.5-0.8kg/cm2, such that the oil can evaporate more quickly and the
volatile gas will not stay in the high-temperature reaction vessel 1 too
long that the volatile gas is scorched excessively or the heavy tars are
reconstituted. Therefore, the reaction can be executed under lower
temperature and in a shorter time to assure safety, and capacity and
quality of the oil products can be improved.
When there is no sign that the internal pressure of the reaction
vessel 1 is rising and almost no oil is continuously produced in the
separation tank 3, the second phase of reaction is accomplished. At
this time, temperature can be set at 350-500 C for example, and a third
phase of thermal pyrolysis cracking process is implemented under the
internal pressure of 0.5-0.8kg/cm2. However, at this time, only a small
amount of heavy oil at a boiling point higher than 350 C will be
disintegrated as gas. As described above, after the gas has been
condensed as oil through the condenser 2 and entered into the
separation tank 3 for separation, the oil will overflow to the overflow
chamber 33, whereas the gas is discharged outside. When executing
this high-temperature thermal pyrolysis cracking process, the reaction
vessel 1 is also kept at low pressure by the suction pump 4 as described
above; therefore, a reaction time is shortened and safety is assured, as
well as capacity and quality of the oil products are improved. When the
7
CA 02681816 2009-10-07
internal pressure of the reaction vessel 1 drops down and almost no
condensate and gas are produced, the second phase of thermal
pyrolysis cracking process is accomplished and residuals of the raw
materials M inside the inner vessel 12 form solid-state carbonized
materials after going through the aforementioned three phases of dry
distillation and carbonization from low temperature to high temperature.
After that, temperature in the reaction vessel 1 is set at activation
temperature of 500700 C and intermittent short-time suction at low
pressure is kept by the suction pump 4, in order to perform a fourth
phase of treatment to activate the solid-state carbonized materials. At
this time, only an extremely small amount of high boiling point gas, such
as heavy metal, is produced. Whereas, after a certain period of time,
like 1-2hrs, the solid-state carbonized materials will become activated
carbons. Following that, the power is turned off to stop operation.
When temperature inside the reaction vessel 1 reduces to normal
temperature, the cover 13 is opened and the inner vessel 12 is removed
outside by a crane or a chain block (not shown in the drawings) to unload
the activated carbons. In addition, another inner vessel 12 which has
been already loaded with the raw wastes is put into the exterior vessel
11 and then the reaction vessel 1 is covered tightly by the cover 13 that a
second cycle of thermal pyrolysis cracking process can be implemented.
Accordingly, these procedures are implemented repeatedly that the
oil product, such as the essential oil, can be extracted from the raw
materials very efficiently with the processing time even shorter than the
conventional methods. At a same time, the activated carbons can be
acquired, as well.
In the thermal pyrolysis cracking process of the aforementioned
embodiment, the entire process is divided into four phases which are
undertaken under various temperatures. However, the aforementioned
first to third phases can be also divided into more temperature gradient
phases to carry out, for example, every 100 C or 150 C. It is also
feasible that if the third phase and the fourth phase are combined as one
phase, and temperature is increased to more than 500 C to execute the
thermal pyrolysis cracking to heavy oil and to activate carbonized
materials, after accomplishing the second phase. At this time, the
processing time is about a summation of the processing times of the
aforementioned third phase and fourth phase. On the other hand, the
aforementioned temperature ranges and temperature gradients of each
phase are only an example and these temperatures can be altered
according to types, properties and shapes of raw materials for
processing. Besides, the separation tank 3 is not limited to the
embodiment in the drawing, all kinds of suitable conventional horizontal
or vertical separation tanks can be used. Moreover, it is also feasible
that the reaction vessel 1 is not provided with the inner vessel 12.
8
CA 02681816 2009-10-07
Referring to FIG. 2, it shows a second embodiment of the present
invention. In the present embodiment, all parts that are equal or similar
to those in the system of the first embodiment are marked by same
symbols and description is omitted.
In the present embodiment, the components are basically the same
as those in the aforementioned embodiment, except that the exhaust
pipe P1 of the separation tank 3 is additionally connected with a second
condenser 2A. An outlet port of this condenser 2A is connected to a
mixing tank 7 and a bottom of the mixing tank 7 is provided with an oil
drain pipe 35a and a valve 34a to guide oil in the tank into the oil tank 36.
An upper part of the mixing tank 7 is provided with an exhaust pipe P2
and the suction pump 4 is provided on this exhaust pipe P2 to replace
the exhaust pipe P1 of the first embodiment. In addition, at the other
end of the separation tank 3 from the oil drain pipe 35, which is provided
with the valve 34, to the mixing tank 7, an interior of the mixing tank 7 is
provided with an electric mixer 71 to scramble and mix the oil which
flows into the mixing tank 7 through the pipe 35 from the separation tank
3, with the oil which is condensed through the second condenser 2A and
drops into the mixing tank 7; whereas, the mixed oil can flow into the oil
tank 36 through the oil drain pipe 35a. The system of this embodiment
is further provided with an ultrasonic generator 8 which is not disclosed
in the first embodiment. The ultrasonic generator 8 is provided at a
bottom of the separation tank 3 to cut off and disintegrate polymer
structures of the oil in the tank by an ultrasonic effect, so as to acquire
more low-molecule light oil. The ultrasonic generator 8 can be
operating at output power density of more than 50w/cm3, and is
preferably operating at 100-200w/cm3 at 20kHz. Cooling temperature
of the second condenser 2A is set to be lower than that of the first
condenser 2 and is usually set at below 15 C, to facilitate re-cooling the
gas from the separation tank 3 as oil. An interior of the exterior tank 21
of the second condenser 2A is not formed with the gas gathering
chamber 23, but only formed with the helical inner tube 22. This type of
condenser is an ordinary conventional one. Other types of condensers
can be used, of course. The exterior tank 21 is also provided with an
inlet and an outlet for cooling fluid which can be cooling water or coolant.
When implementing the method for extracting the oil product by the
aforementioned system, the operation and the reaction process from the
reaction vessel 1 to the separation tank 3 are basically the same as
those in the first embodiment, with an exception that the non-liquefied
gas in the separation tank 3 is guided into the second condenser 2A for
cooling once more with low temperature, such that part of the gas is
condensed as oil which flows into the mixing tank 7 and is mixed with the
oil from the separation tank 3 by the mixer 8 and is then gathered in the
oil tank 6, whereas the still non-liquefied gas is discharged outside from
9
CA 02681816 2009-10-07
the exhaust pipe P2. In short, the gas which is produced by carrying
out the thermal pyrolysis cracking to the raw materials M under a
vacuum and oxygen-free condition in the reaction vessel 1 flows into the
first condenser 2, is cooled down as liquid and then flows into the
separation tank 3. Polymer structures of heavy oil are cut off here by
the ultrasonic effect generated by the ultrasonic generator 8, thereby
increasing production of light oil. On the other hand, the non-liquefied
gas is cooled down again by the second condenser 2A, allowing part of
the gas to be condensed as oil to be stored in the mixing tank 7 and
mixed with the oil from the separation tank 3, thereby increasing the
amount of oil to be gathered and improving the quality. The
non-liquefied gas in the mixing tank 7, whereas, is discharged outside by
the suction pump 4. Upon implementing this method, the way that the
control booth 5 and the pump 4 control in phases temperature in the
reaction vessel 1 and suck out air to reduce pressure at any time is
similar to that in the first embodiment. Therefore, it will not be
addressed further to avoid repetition. After one cycle of thermal
pyrolysis cracking process has been accomplished, in addition to that
the oil tank 7 can acquire more and higher quality oil products than the
first embodiment, the reaction vessel 1 can also acquire high value
activated carbons.
Furthermore, in the present embodiment, the suction pump 4 can be
also provided midway in the exhaust pipe P1, i.e., an upstream end of
the second condenser 2A, as in the first embodiment.
Referring to FIG. 3, it shows a third embodiment of the present
invention. This system is physically identical to the system of the first
embodiment, except that at the outlet port of the condenser 2 (i.e. the
inlet port of the separation tank 3), the exhaust pipe P is connected to a
reverse tube p, an upper end of which is connected to an upstream end
of the exhaust pipe P (i.e. the inlet port of the condenser 2). Therefore,
the non-liquefied gas will flow reversely to the exhaust pipe P through
this reverse tube p, merge with the distilled gas and then flow into the
condenser 2 for condensation, so as to increase the amount of oil that is
gathered. In addition, the bottom of the separation tank 3 is also
provided with the ultrasonic generator 8, a function of which is same as
that in the first embodiment.
The operation process by which the raw wastes are undergone with
the thermal pyrolysis cracking process to make the oil with the
aforementioned system is physically the same as that in the first
embodiment, except that part of the non-condensed and non-liquefied
gas will flow reversely to the condenser 2 for condensation again, in
order to increase the amount of oil to be gathered. To avoid repetition,
the description is not provided further.
Hereinbefore are descriptions to the preferred embodiments of the
CA 02681816 2009-10-07
present invention, and all kinds of modifications and alterations can be
still made without violating the principles and characteristics of the
present invention. For example, the separation tank 3 of the system in
the first embodiment can be provided with the ultrasonic generator 8,
and in the system of the second embodiment, the oil of the separation
tank 3 and the mixing tank 7 can be gathered separately without mixing.
At this time, the oil drain pipe with two outlets (not shown in the drawings)
should be provided with a bi-directional switch valve to guide the oil into
the mixing tank or another oil tank. These should be taken as being
covered in the following claims.
It is of course to be understood that the embodiments described
herein is merely illustrative of the principles of the invention and that a
wide variety of modifications thereto may be effected by persons skilled
in the art without departing from the spirit and scope of the invention as
set forth in the following claims.
