Note: Descriptions are shown in the official language in which they were submitted.
CONDENSIBLE GAS BOTANICAL EXTRACTION SYSTEMS AND METHODS
FIELD
[0001] This disclosure relates generally to apparatus and methods for
the
extraction of compounds from botanical material using a condensable gas
solvent. More specifically, this disclosure relates to apparatus and methods
for
the extraction of compounds from cannabis, such as aliphatic aldehydes,
monoterpenes, and cannabinoids.
INTRODUCTION
[0002] The following is not an admission that anything discussed below is
part of the prior art or part of the common general knowledge of a person
skilled
in the art.
[0003] Botanicals extracts are a growing product class in the
cannabis
industry. Advantageously, extracts may have some or all of the benefits of the
original plant, in a convenient concentrated form.
[0004] Popular methods used to extract various compounds from
botanicals involve the use of solvents, typically alcohol or water (often in
the form
of steam). These solvents diffuse the plant material and draw out one or more
plant compounds. More often than not, the solvent is removed from the final
extract. In order to extract the more hydrophobic compounds, hydrocarbon or
chlorinated solvents may be used, subsequently leaving residues that may be
challenging to remove or minimize.
SUMMARY
[0005] The following introduction is provided to introduce the reader
to the
more detailed discussion to follow. The introduction is not intended to limit
or
define any claimed or as yet unclaimed invention. One or more inventions may
reside in any combination or sub-combination of the elements or process steps
disclosed in any part of this document including its claims and figures.
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[0006] Condensable gas solvent may be used to extract one or more
compounds from botanical material, such as a cannabis feedstock.
Advantageously, condensable gases can be liquefied at moderate pressures at
ambient temperature. Condensable gas solvents may also for be used for
extraction at relatively wide temperature and pressure range. This may enable
improved solubility performance, and/or provide a more complete extraction in
less time when compared to other solvents.
[0007] In particular, carbon dioxide (CO2) is considered to be a
preferred
solvent for cannabis extraction. For example, it is regarded as non-toxic,
environmentally friendly, relatively inexpensive, and leaves no residue when
the
extracted compounds are separated from the solvent. Also, the low viscosity of
supercritical carbon dioxide may allow it to penetrate into botanical material
more
easily, while its diffusivity may allow for faster extractions.
[0008] In accordance with one aspect of this disclosure, which may be
.. used alone or in combination with one or more other aspects, apparatus for
the
extraction of compounds from botanical material using a condensable gas
solvent includes using a sonic flow nozzle that is positioned adjacent a
cyclone
chamber to introduce a mixture of a solvent and a botanical extract into a
cyclone
chamber. The sonic flow nozzle may be proximate (e.g., immediately upstream
of) a tangential fluid inlet of the cyclone chamber or a tangential inlet may
comprise or consist of a sonic flow nozzle.
[0009] According to this aspect, the feed to a cyclone separator
(e.g., a
compressible gas solvent (e.g. CO2) and a botanical extract dissolved therein)
may be accelerated to sonic or supersonic speeds and introduced directly into
the cyclone chamber. Accordingly, a solvent containing extracted botanical
elements may exit the sonic flow nozzle at a supersonic velocity and be
directly
tangentially introduced into a cyclone separator. An advantage of this design
is
that it may promote greater separation efficiency, in that most, substantially
all, or
essentially all of the extracted material dissolved or contained in the
solvent
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stream may be separated from the gas solvent. For example, more than 85%,
90%, 95%, 96%, 97%, 98%, or 99% of the extracted material dissolved in the
solvent stream may be separated from the gas solvent as an unfoamed extract
as exemplified in Figure 9. As a result, gaseous solvent exiting the cyclonic
separator may have little or no solute. For example, less than 15%, 10%, 5%,
4%, 3%, , 2%
/ or 1% of extracted botanical compound(s) may remain in the
gaseous solvent exiting the cyclonic separator. A further advantage is that
this
may allow 'clean' (i.e. substantially or completely extract-free) solvent to
be
recycled to an extraction chamber.
[0010] This separation efficiency may be contrasted with typical cyclone
separator systems which use a typical cyclone inlet wherein there may be
significant volumes of solvent in the botanical extract exiting a cyclone
separator.
For example, the botanical extract exiting a cyclone separator may be in the
form
of an emulsion or foamed liquid extract which may contain 2% or more solvent
(see for example Figure 8). The downstream processing of such products is
difficult as the extract is not easily flowable and may foul the low pressure
piping
and compression pumps downstream of the separator.
[0011] In contrast, in accordance with this aspect, the solvent-
extract
stream from the extraction chamber may undergo simultaneous depressurization
.. and acceleration immediately upstream of, or as it enters the cyclone
chamber,
forming liquid droplets of extracted compounds which may flow under the
influence of gravity down the wall of a cyclone separator so as to be
collected as,
e.g., an unfoamed liquid (see for example Figure 9).
[0012] A further advantage of this aspect is that it may allow the
sonic flow
nozzle to be operated in a 'choked' state. An advantage of operating the flow
nozzle under 'choked' conditions is that pressure disturbances upstream of the
sonic flow nozzle may be inhibited or prevented from moving downstream into
the cyclonic separator, and thus may be inhibited or prevented from causing
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undesirable pulsations and/or vortex flow instabilities during the
decompression
and/or separation that occurs in the cyclonic separator.
[0013] In accordance with this aspect, there is provided an
apparatus for
the extraction of compounds from botanical material using a condensable gas
solvent, the apparatus comprising:
(a) an extraction chamber having a solvent outlet;
(b) a cyclonic separator comprising a cyclone chamber having a cyclonic
tangential fluid inlet and a fluid outlet;
(c) a solvent flow path extending from the solvent outlet of the extraction
chamber to the cyclonic tangential fluid inlet; and,
(d) a sonic flow nozzle positioned in the solvent flow path adjacent the
cyclonic tangential fluid inlet.
[0014] In any embodiment, the sonic flow nozzle may be positioned at
an
upstream end of the cyclonic tangential fluid inlet whereby the solvent
passing
through the sonic flow nozzle enters the cyclone chamber at sonic velocity.
[0015] In any embodiment, the sonic flow nozzle may comprise the
cyclonic tangential fluid inlet.
[0016] In any embodiment, the extraction chamber may be operated
below
0 C and with the solvent in a liquid or a supercritical phase, and the solvent
flow
path may further comprise a heater proximate an inlet of the sonic flow nozzle
wherein the solvent exiting the heater is gaseous.
[0017] In any embodiment, the apparatus may further comprise a
solvent
return path extending from the fluid outlet of the cyclonic separator to the
extraction chamber.
[0018] In any embodiment, the outlet of the sonic flow nozzle may be
positioned at an inlet port of the cyclone separator.
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[0019] In
accordance with this aspect, there is also provided a method for
extracting compounds from botanical material using a condensable gas solvent,
the method comprising:
(a) in an extraction chamber, using the condensable gas solvent to extract
at least one compound from a feedstock of botanical material;
(b) withdrawing a liquid solvent containing the at least one compound
extracted from the feedstock from the extraction chamber and conveying the
liquid solvent through a solvent flow path to a sonic flow nozzle and
obtaining
solvent at a supersonic velocity; and,
(c) directly tangentially introducing the solvent exiting the sonic flow
nozzle
at a supersonic velocity into a cyclone separator.
[0020] In
any embodiment, the solvent in the flow path may be in a phase
comprising at least one of a supercritical phase and a liquid phase.
[0021] In
any embodiment, the solvent in the extraction chamber may be
in a liquid phase and the solvent in the flow path may be in a supercritical
phase.
[0022] In
any embodiment, the method may further comprise heating the
solvent to a gaseous phase prior to the solvent entering the sonic flow
nozzle.
[0023] In
any embodiment, the solvent in the extraction chamber may be
in a liquid phase and the solvent in the flow path may be in a supercritical
phase.
[0024] In any embodiment, the method may further comprise separating at
least a portion of the at least one compound from the solvent in the cyclone
separator and collecting the at least one compound as an unfoamed liquid.
[0025] In
any embodiment, the method may further comprise heating the
cyclone separator whereby the at least one compound that is separated in the
cyclone separator may be heated and its viscosity may be reduced.
[0026] In
any embodiment, the outlet of the sonic flow nozzle may be
positioned adjacent the cyclone separator and the method may further comprise
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directing solvent exiting the sonic flow nozzle to avoid the solvent
contacting an
inlet port of the cyclone separator.
[0027] In any embodiment, the outlet of the sonic flow nozzle may be
positioned at an inlet port of the cyclone separator and the method may
further
comprise conveying solvent exiting the sonic flow nozzle immediately into the
cyclone separator.
[0028] In any embodiment, the feedstock of botanical material may
comprise cannabis and the method may further comprise obtaining as the at
least one compound extracted from the feedstock at least one of an aliphatic
aldehyde, a terpene, and a cannabinoid.
[0029] In accordance with another aspect of this disclosure, which
may be
used alone or in combination with one or more other aspects, a method for
extracting compounds from botanical material comprising cannabis using a
condensable gas solvent includes extracting a compound from the cannabis
using condensable gas solvent in a liquid and/or supercritical phase. A liquid
stream of solvent and the extracted compound is conveyed to a cyclone
chamber, and solvent in the liquid stream is converted to a gaseous phase
upstream of the cyclone chamber. Solvent in the gaseous phase is then directed
into the cyclone chamber at sonic velocity.
[0030] An advantage of this aspect is that solvent containing extracted
compounds may be maintained in a liquid and/or supercritical phase upstream of
the cyclone chamber, which may facilitate maintaining the solvent density at a
level sufficient to inhibit or prevent the extracted compounds from being
disassociated from the solvent upstream of the cyclone chamber thereby
preventing or reducing fouling of the flow path from the extractor to the
cyclone
separator.
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[0031] In accordance with this aspect, there is provided a method for
extracting compounds from botanical material comprising cannabis using a
condensable gas solvent, the method comprising:
(a) in an extraction chamber, using the condensable gas solvent in a
phase comprising at least one of a supercritical phase and a liquid phase to
extract at least one compound from the cannabis;
(b) withdrawing a liquid stream comprising the solvent the at least one
compound and conveying the liquid stream along a solvent flow path extending
from the extraction chamber to a cyclone chamber having a fluid inlet;
(c) converting the solvent in the liquid stream to a gaseous phase
upstream of the cyclone chamber; and,
(d) directing the solvent in the gaseous phase into the cyclone chamber
via the fluid inlet at sonic velocity.
[0032] In any embodiment, conveying the liquid stream containing the
at
least one compound may comprise directing solvent through a sonic flow nozzle
positioned in the solvent flow path upstream of the fluid inlet.
[0033] In any embodiment, the fluid inlet may comprise the sonic flow
nozzle.
[0034] In any embodiment, the fluid inlet may be a tangential air
inlet.
[0035] In any embodiment, the method may further comprise separating at
least a portion of the at least one compound from the solvent in the cyclone
chamber and collecting the at least one compound as an unfoamed liquid.
[0036] In any embodiment, the method may further comprise heating the
cyclone chamber whereby the at least one compound that is separated in the
cyclone chamber may be heated and its viscosity may be reduced.
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[0037] In any embodiment, the method may further comprise selecting
the
condensable gas solvent from at least one of carbon dioxide, a hydrocarbon,
preferably a haloalkane, Xenon, nitrous oxide, and sulfur hexafluoride.
[0038] In any embodiment, the method may further comprise selecting
carbon dioxide as the condensable gas solvent.
[0039] In any embodiment, the at least one compound extracted from
the
feedstock may comprise at least one of an aliphatic aldehyde, a ketone, an
ester,
a terpene, and a cannabinoid.
[0040] In accordance with another aspect of this disclosure, which
may be
used alone or in combination with one or more other aspects, a method for
extracting compounds from botanical material comprising cannabis using a
condensable gas solvent includes providing a frozen feedstock of botanical
material (e.g. all or substantially all of the water in the feedstock is in a
solid
phase) to an extraction chamber, and extracting a compound from the feedstock
using a condensable gas solvent while maintaining the feedstock in a frozen
state.
[0041] An advantage of extracting compounds from frozen botanical
material is that it may impede or prevent water in the botanical material from
being dissolved by the solvent. This may result in a more 'complete' extract
being
obtained, and may also improve the speed and/or efficiency of the solvent
extraction. For example, some terpenes are somewhat water soluble. If the
recovered extract contains a significant amount of water, then when the water
is
removed, some of the terpenes may be lost.
[0042] Another possible advantage is that this may reduce or obviate
the
need to desiccate the material prior to extraction. This may be particularly
advantageous for extracting compounds from a cannabis feedstock. For
example, one or more compounds typically present in cannabis may be lost,
damaged, or otherwise adversely affected during a typical drying process.
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[0043] In
accordance with this broad aspect, there is provided a method
for extracting compounds from botanical material comprising cannabis using a
condensable gas solvent, the method comprising:
(a) providing a feedstock of the botanical material to an extraction
chamber wherein water in the feedstock is in a solid phase;
(b) extracting at least one compound from the feedstock of the botanical
material using the condensable gas solvent while maintaining the feedstock in
a
frozen state and obtaining solvent containing the at least one extracted
compound;
(c) withdrawing a solvent stream containing the at least one extracted
compound from the extraction chamber; and,
(d) separating the at least one extracted compound from the solvent
stream.
[0044] In
any embodiment, the feedstock of botanical material provided in
the extraction chamber may have a moisture content of at least 9%.
[0045] In
any embodiment, the feedstock of botanical material provided in
the extraction chamber may have a moisture content of at least 12%.
[0046] In
any embodiment, in step (a) at least 50% of the water in the
feedstock may be in the solid phase.
[0047] In any embodiment, the method may further comprise controlling
process conditions of the extraction chamber such that the solvent in the
extraction chamber is in at least one of a liquid phase and a supercritical
phase.
[0048] In
any embodiment, step (d) may comprise separating the at least
one extracted compound from the solvent stream in a cyclonic separator.
[0049] In any embodiment, in step (a), the feedstock may be introduced
into the extraction chamber in an unfrozen state.
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[0050] In any embodiment, the feedstock of botanical material
introduced
to the extraction chamber may have a moisture content of at least 5%.
[0051] In any embodiment, the solvent in the extraction chamber may
be
in a liquid phase.
[0052] In any embodiment, the method may further comprise obtaining
fresh feedstock and step (a) may comprise introducing the fresh feedstock into
the extraction chamber.
[0053] In any embodiment, the method may further comprise introducing
the fresh feedstock having a moisture content of at least 5% into the
extraction
chamber.
[0054] In any embodiment, the solvent in the extraction chamber may
be
in a liquid phase.
[0055] In any embodiment, the at least one compound extracted from
the
feedstock may comprise at least one of an aliphatic aldehyde, a terpene, and a
cannabinoid.
[0056] In accordance with another aspect of this disclosure, which
may be
used alone or in combination with one or more other aspects, a method for
extracting compounds from botanical material using a condensable gas solvent
includes extracting the botanical material at conditions at which a
condensable
.. solvent is in a liquid phase and heating the solvent containing at least
one
compound extracted from the botanical material in a heating zone located
upstream from a cyclone separator. The heating zone may be proximate to or
immediately upstream of a cyclone separator. Accordingly, the solvent is
heated
and conveyed to a cyclone chamber (e.g., a tangential inlet of a cyclone
separator, which may comprise or consist of a sonic flow nozzle) at conditions
at
which the solvent is in a gaseous phase. Accordingly, the solvent may be
conveyed to the cyclone inlet as a liquid and converted to a gas upstream or
immediately upstream of a sonic flow nozzle or a tangential cyclone inlet.
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[0057]
An advantage of this design is that solvent containing extracted
compounds may be heated and brought to an inlet of a flow nozzle in a gaseous
phase, which may facilitate maintaining the solvent density at a level
sufficient to
inhibit or prevent the extracted compounds from being disassociated from the
solvent upstream of the flow nozzle, thereby preventing or reducing fouling of
the
flow path from the extractor to the cyclone separator.
[0058]
In accordance with this broad aspect, there is provided a method
for extracting compounds from botanical material using a condensable gas
solvent, the method comprising:
(a) providing a feedstock of botanical material and condensable gas
solvent in an extraction chamber at conditions at which the solvent is at
least
primarily in a liquid phase;
(b) conveying solvent containing at least one compound extracted from
the feedstock along a solvent flow path extending from the extraction chamber
to
a heating zone;
(c) heating the solvent and conveying the solvent from the heating zone to
an inlet of a flow nozzle at conditions at which the solvent is at least
primarily in a
gaseous phase; and,
(d) directing the gaseous solvent to a cyclone chamber and operating the
cyclone chamber at conditions at which the solvent within the cyclone chamber
is
primarily in a gas phase and the at least one compound extracted from the
feedstock is primarily in a liquid phase.
[0059]
In any embodiment, the flow nozzle may be a sonic flow nozzle and
the method may further comprise obtaining solvent exits the outlet of the flow
nozzle at sonic velocity.
[0060]
In any embodiment, controlling process conditions of the extraction
chamber may comprise bringing the temperature of solvent in the extraction
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chamber to a temperature at or below the freezing point of water, such that at
least a portion of water in the feedstock of botanical material is in a solid
phase.
[0061] In accordance with another aspect of this disclosure, which
may be
used alone or in combination with one or more other aspects, apparatus for the
extraction of compounds from botanical material is provided. The apparatus
includes an extraction chamber, and two or more cyclonic separation stages for
removing extracted compounds from a solvent stream. At least one valve is
operable to selectively direct solvent from the extraction chamber to one of
the
cyclonic separation stages.
[0062] An advantage of this design is that the cyclonic separation stages
may each be configured to preferentially separate certain compounds or classes
of compounds from a solvent stream. For example, a first cyclonic separator
may
be configured or 'tuned' to preferentially remove a first series of extracted
compounds from a solvent stream, and a second cyclonic separator may be
configured or 'tuned' to preferentially remove a second, higher molecular
weight,
series of extracted compounds from a solvent stream. This may allow a solvent
stream containing certain compound(s) to be directed from the extraction
chamber to the cyclonic separator best suited to remove those compound(s).
[0063] In accordance with this broad aspect, there is provided
apparatus
for the extraction of compounds from botanical material, the apparatus
comprising:
(a) an extraction chamber;
(b) a first cyclonic separation stage comprising at least one first stage
cyclonic separator wherein the at least one first stage cyclonic separator is
configured to remove a first series of extracted compounds having a first
average
molecular weight from a solvent stream;
(c) a first solvent flow path extending from the extraction chamber to the
first cyclonic separation stage;
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(d) a second cyclonic separation stage comprising at least one second
stage cyclonic separator wherein the at least one second stage cyclonic
separator is configured to remove a second series of extracted compounds from
a solvent stream wherein the second series of extracted compounds has a
second average molecular weight that is higher than the first average
molecular
weight;
(e) a second solvent flow path extending from the extraction chamber to
the second cyclonic separation stage; and,
(f) at least one valve operable to selectively direct solvent exiting the
extraction chamber to one of the first cyclonic separation stage and the
second
cyclonic separation stage.
[0064] In any embodiment, the apparatus may further comprise:
a third cyclonic separation stage comprising at least one third stage
cyclonic separator wherein the at least one third cyclonic stage separator is
configured to remove a third series of extracted compounds from a solvent
stream wherein the third series of extracted compounds has a third average
molecular weight that is higher than the second average molecular weight; and,
a third solvent flow path extending from the extraction chamber to the third
cyclonic separation stage,
wherein the at least one valve is operable to selectively direct solvent
exiting the extraction chamber to one of the first cyclonic separation stage,
the
second cyclonic separation stage, and the third cyclonic separation stage.
[0065] In any embodiment, solvent obtained from the extraction
chamber
may rotate at a first speed in the at least one first stage cyclonic separator
and
solvent obtained from the extraction chamber may rotate at a second speed in
the at least one second stage cyclonic separator wherein the second speed may
be different than the first speed.
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[0066] In any embodiment, solvent obtained from the extraction
chamber
may rotate at a first speed in the at least one first stage cyclonic
separator,
solvent obtained from the extraction chamber may rotate at a second speed in
the at least one second stage cyclonic separator wherein the second speed may
be different than the first speed, and solvent obtained from the extraction
chamber may rotate at a third speed in the at least one third cyclonic
separator
wherein the third speed may be different than the first speed and the second
speed.
[0067] In any embodiment, the first solvent flow path may comprise a
common solvent flow path portion downstream of the extraction chamber and
upstream of the at least one valve and a first segregated solvent flow path
portion downstream of the at least one valve and upstream of the first
cyclonic
separation stage, and wherein the second solvent flow path may comprise the
common solvent flow path portion and a second segregated solvent flow path
portion downstream of the at least one valve and upstream of the second
cyclonic separation stage.
[0068] In any embodiment, the first solvent flow path may comprise a
common solvent flow path portion downstream of the extraction chamber and
upstream of the at least one valve and a first segregated solvent flow path
portion downstream of the at least one valve and upstream of the first
cyclonic
separation stage, and wherein the second solvent flow path may comprise the
common solvent flow path portion and a second segregated solvent flow path
portion downstream of the at least one valve and upstream of the second
cyclonic separation stage, and wherein the third solvent flow path may
comprise
the common solvent flow path portion and a third segregated solvent flow path
portion downstream of the at least one valve and upstream of the third
cyclonic
separation stage.
[0069] In any embodiment, the apparatus may further comprise an
extraction control system for regulating at least one of a temperature and a
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pressure of solvent in the extraction chamber, the extraction control system
may
be configured to operate the extraction chamber under at least a first set of
process conditions and a second set of process of conditions, and wherein,
while
the extraction chamber is being operated under the first set of process
conditions, the at least one valve may be configured to direct solvent exiting
the
extraction chamber to the first cyclonic separation stage, and wherein, while
the
extraction chamber is being operated under the second set of process
conditions, the at least one valve may be configured to direct solvent exiting
the
extraction chamber to the second cyclonic separation stage.
[0070] In accordance with another aspect of this disclosure, which may be
used alone or in combination with one or more other aspects, a method of
extracting compounds from botanical material is provided. First, solvent is
used
under a first set of process conditions to preferentially extract a first
compound
from a feedstock of botanical material, and solvent containing the first
extracted
.. compound is conveyed to a first cyclonic separation stage. Next, solvent is
used
under a second set of process conditions to preferentially extract a second
compound from the feedstock, and solvent containing the second extracted
compound is conveyed to a second cyclonic separation stage.
[0071] An advantage of using condensable gas as a solvent is that it
may
allow the preferential extraction (or 'targeted' extraction) of one or more
individual
compounds from a botanical feedstock. For example, controlling the density of
solvent during the extraction process (e.g. by altering the temperature and/or
pressure of solvent in a liquid and/or supercritical phase) may promote
conditions
in which the solubility and/or rate of solution of one or more compounds
(e.g.,
one or more terpenes) present in the botanical material is relatively high in
comparison with other compounds (e.g., other terpenes) present in the
botanical
material. Under such conditions, one or more 'targeted' compound class(es) may
be dissolved by the solvent and drawn from the botanical material in
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disproportionate quantities and/or at a disproportionate rate to other
compounds
present in the botanical material.
[0072]
Another advantage of this design is that the cyclonic separation
stages may each be configured or 'tuned' to preferentially separate certain
compounds from solvent. For example, a first cyclonic separator may be
configured to preferentially remove a first 'targeted' extracted compound(s)
(e.g.,
one or more terpenes) from a solvent stream, and a second cyclonic separator
may be configured to preferentially remove a second 'targeted' extracted
compound(s) (e.g., other terpenes) from the solvent. This may allow solvent
containing certain targeted compound(s) to be directed to a cyclonic separator
best suited to disassociate those compound(s) from solvent.
[0073] In
accordance with this aspect, there is provided a method for
extracting compounds from botanical material using apparatus comprising an
extraction chamber, a first cyclonic separation stage comprising at least one
first
stage cyclonic separator, and a second cyclonic separation stage comprising at
least one second stage cyclonic separator, the method comprising:
(a) introducing a feedstock of botanical material into the extraction
chamber;
(b) operating the extraction chamber using a first solvent under a first set
of process conditions to preferentially extract a first compound from the
feedstock;
(c) conveying the first solvent containing the first extracted compound from
the extraction chamber to the first cyclonic separation stage along a first
solvent
flow path;
(d) separating the first extracted compound from the first solvent in the
first
cyclonic separation stage;
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(e) operating the extraction chamber using a second solvent under a
second set of process conditions to preferentially extract a second compound
from the feedstock;
(f) conveying the second solvent containing the second extracted
compound from the extraction chamber to the second cyclonic separation stage
along a second solvent flow path; and,
(g) separating the second extracted compound from the second solvent in
the second cyclonic separation stage.
[0074] In
any embodiment, the method may further comprise recycling the
first solvent from the first cyclonic separation stage to the extraction
chamber.
[0075] In
any embodiment, the method may further comprise recycling the
second solvent from the first cyclonic separation stage to the extraction
chamber.
[0076] In
any embodiment, the second solvent may be selected to be the
same as the first solvent.
[0077] In accordance with another aspect of this disclosure, which may be
used alone or in combination with one or more other aspects, a method for
extracting compounds from botanical material using a condensable gas solvent
includes conducting sequential extraction operations to sequentially extract
heavier molecular weight compounds and conveying the solvent from the
extraction operations sequentially though cyclonic separation stages to
sequentially obtain recovered extracts having lighter molecular weights.
[0078] In
accordance with this aspect, there is provided an apparatus for
the extraction of compounds from botanical material, the apparatus comprising:
(a) an extraction chamber;
(b) a first cyclonic separation stage comprising at least one first stage
cyclonic separator wherein the at least one first stage cyclonic separator is
configured to remove a first series of extracted compounds having a first
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average molecular weight from a solvent stream obtained from the
extraction chamber;
(c) a first solvent flow path extending from the extraction chamber to the
first cyclonic separation stage;
(d) a second cyclonic separation stage comprising at least one second
stage cyclonic separator wherein the at least one second stage cyclonic
separator is configured to remove a second series of extracted
compounds from a solvent stream obtained from the first cyclonic
separation stage wherein the second series of extracted compounds has a
second average molecular weight that is lower than the first average
molecular weight; and,
(e) a second solvent flow path extending from the first cyclonic separation
stage to the second cyclonic separation stage.
[0079] In
any embodiment, the apparatus may further comprise a third
cyclonic separation stage comprising at least one third stage cyclonic
separator
wherein the at least one third cyclonic stage separator is configured to
remove a
third series of extracted compounds from a solvent stream wherein the third
series of extracted compounds has a third average molecular weight that is
lighter than the second average molecular weight; and, a third solvent flow
path
extending from the second cyclonic separation stage to the third cyclonic
separation stage.
[0080] In
any embodiment, the solvent obtained from the extraction
chamber may rotate at a first speed in the at least one first stage cyclonic
separator and solvent obtained from the extraction chamber may rotate at a
second speed in the at least one second stage cyclonic separator wherein the
second speed may be higher than the first speed.
[0081] In
any embodiment, the solvent obtained from the extraction
chamber may rotate at a first speed in the at least one first stage cyclonic
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separator, solvent obtained from the extraction chamber may rotate at a second
speed in the at least one second stage cyclonic separator wherein the second
speed may be higher than the first speed, and solvent obtained from the
extraction chamber may rotate at a third speed in the at least one third
cyclonic
separator wherein the third speed may be higher than the second speed.
[0082] In accordance with this aspect, there is also provided a
method for
extracting compounds from botanical material using apparatus comprising an
extraction chamber, a first cyclonic separation stage comprising at least one
first
stage cyclonic separator, and a second cyclonic separation stage comprising at
least one second stage cyclonic separator, the method comprising:
(a) introducing a feedstock of botanical material into the extraction
chamber;
(b) conducting a first extraction operation in which the extraction chamber
is operated using a solvent under a first set of process conditions to
preferentially extract a first compound from the feedstock;
(c) subsequently conducting a second extraction operation in which the
extraction chamber is operated using the solvent under a second set of
process conditions to preferentially extract a second compound from the
feedstock wherein the second compound has a higher molecular weight
than the first compound;
(d) conveying the solvent from each extraction operation to the first
cyclonic separation stage and separating the first extracted compound
from the solvent in the first cyclonic separation stage; and,
(e) conveying partially treated solvent obtained from the first cyclonic
separation stage to the second cyclonic separation stage and separating
the second extracted compound from the partially treated solvent in the
second cyclonic separation stage.
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[0083] In any embodiment, the method may further comprise obtaining
fully extracted solvent from the second cyclonic separation stage and
recycling
the fully extracted solvent to the extraction chamber.
[0084] In any embodiment, the solvent obtained from the extraction
chamber may rotate at a first speed in the at least one first stage cyclonic
separator and the partially extracted solvent may rotate at a second speed in
the
at least one second stage cyclonic separator wherein the second speed may be
higher than the first speed.
[0085] It will be appreciated by a person skilled in the art that an
apparatus
or method disclosed herein may embody any one or more of the features
contained herein and that the features may be used in any particular
combination
or sub-combination.
[0086] These and other aspects and features of various embodiments
will
be described in greater detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0087] For a better understanding of the described embodiments and to
show more clearly how they may be carried into effect, reference will now be
made, by way of example, to the accompanying drawings in which:
[0088] Figure 1 is a schematic view of an apparatus for the
extraction of
compounds from a botanical material in accordance with one embodiment;
[0089] Figure 2 is a top schematic view of the extraction chamber,
solvent
flow path, sonic flow nozzle, cyclone chamber, and cyclonic tangential fluid
inlet
of the apparatus of Figure 1;
[0090] Figure 3 is a cross-section view of the sonic flow nozzle of
the
apparatus of Figure 1;
[0091] Figure 4 is a cross-section view of the cyclonic separator of
the
apparatus of Figure 1;
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CA 2990050 2017-12-21
[0092] Figure 5 is a schematic view of apparatus for the extraction
of
compounds from a botanical material in accordance with another embodiment;
[0093] Figure 6 is a simplified process flow diagram for a method for
extracting compounds from botanical material using a condensable gas solvent
in accordance with one embodiment;
[0094] Figure 7 is a simplified process flow diagram for a method for
extracting compounds from botanical material using apparatus comprising an
extraction chamber, a first cyclonic separation stage comprising at least one
first
stage cyclonic separator, and a second cyclonic separation stage comprising at
least one second stage cyclonic separator in accordance with one embodiment;
[0095] Figure 8 is an image of a foamed extract exiting a cyclone
chamber
wherein a sonic flow nozzle is not utilized; and,
[0096] Figure 9 is an image of an extract obtained from a cyclone
separator wherein a sonic flow nozzle was utilized.
[0097] The drawings included herewith are for illustrating various
examples of articles, methods, and apparatuses of the teaching of the present
specification and are not intended to limit the scope of what is taught in any
way.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0098] Various apparatuses, methods and compositions are described
below to provide an example of an embodiment of each claimed invention. No
embodiment described below limits any claimed invention and any claimed
invention may cover apparatuses and methods that differ from those described
below. The claimed inventions are not limited to apparatuses, methods and
compositions having all of the features of any one apparatus, method or
composition described below or to features common to multiple or all of the
apparatuses, methods or compositions described below. It is possible that an
apparatus, method or composition described below is not an embodiment of any
claimed invention. Any invention disclosed in an apparatus, method or
- 21 -
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composition described below that is not claimed in this document may be the
subject matter of another protective instrument, for example, a continuing
patent
application, and the applicant(s), inventor(s) and/or owner(s) do not intend
to
abandon, disclaim, or dedicate to the public any such invention by its
disclosure
in this document.
[0099] The terms "an embodiment," "embodiment," "embodiments," "the
embodiment," "the embodiments," "one or more embodiments," "some
embodiments," and "one embodiment" mean "one or more (but not all)
embodiments of the present invention(s)," unless expressly specified
otherwise.
[00100] The terms "including," "comprising" and variations thereof mean
"including but not limited to," unless expressly specified otherwise. A
listing of
items does not imply that any or all of the items are mutually exclusive,
unless
expressly specified otherwise. The terms "a," "an" and "the" mean "one or
more,"
unless expressly specified otherwise.
[00101] As used herein and in the claims, two or more parts are said to be
"coupled", "connected", "attached", or "fastened" where the parts are joined
or
operate together either directly or indirectly (i.e., through one or more
intermediate parts), so long as a link occurs. As used herein and in the
claims,
two or more parts are said to be "directly coupled", "directly connected",
"directly
attached", or "directly fastened" where the parts are connected in physical
contact with each other. None of the terms "coupled", "connected", "attached",
and "fastened" distinguish the manner in which two or more parts are joined
together.
[00102] Furthermore, it will be appreciated that for simplicity and
clarity of
illustration, where considered appropriate, reference numerals may be repeated
among the figures to indicate corresponding or analogous elements. In
addition,
numerous specific details are set forth in order to provide a thorough
understanding of the example embodiments described herein. However, it will be
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understood by those of ordinary skill in the art that the example embodiments
described herein may be practiced without these specific details. In other
instances, well-known methods, procedures, and components have not been
described in detail so as not to obscure the example embodiments described
herein. Also, the description is not to be considered as limiting the scope of
the
example embodiments described herein.
General description of an apparatus for the extraction of compounds from
botanical material
[00103] Referring to Figures 1 to 4, an exemplary embodiment of an
apparatus for the extraction of compounds from botanical material (which may
be
referred to as a botanical feedstock and is preferably cannabis) is shown
generally as 1000. The following is a general discussion of this embodiment
which provides a basis for understanding several of the features which are
discussed herein. As discussed subsequently, each of the features may be used
individually or in any particular combination or sub-combination in this or in
other
embodiments disclosed herein.
[00104] In the illustrated embodiment, the apparatus extracts
compounds
from a botanical feedstock (e.g. cannabis) using a condensable gas solvent.
[00105] In any of the embodiments disclosed herein, the solvent may be
a
condensable gas. Optionally, the solvent comprises carbon dioxide (CO2). Use
of
CO2 as a solvent may have one or more advantages. For example, carbon
dioxide extraction may provide relatively pure, solvent-free extracts, e.g. it
may
leave little or no residue in the extracted compounds. It may also be
characterized as an environmentally friendly or 'green' alternative to other
solvent-based extraction techniques. Also, the density of CO2 can be altered
by
varying the pressure and temperature, which may allow for selective extraction
of
one or more targeted compounds. Also, the low viscosity of supercritical
carbon
dioxide may allow it to penetrate into the botanical material more easily,
while its
diffusivity may allow for faster extractions.
- 23 -
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[00106] Alternatively, the condensable gas solvent may include one or
more
of a hydrocarbon (such as ethane, propane, butane, cyclopropane, ethane),
optionally a haloalkane, xenon, krypton, nitrous oxide, and sulfur
hexafluoride.
The selection of a particular condensable gas may be influenced by the strain
of
cannabis from which compounds are to be extracted, the particular compound or
compounds targeted for preferential extraction, and/or a targeted speed and/or
efficiency of the extraction.
[00107] As exemplified in Figures 1 to 4, apparatus 1000 comprises at
least
one extraction chamber 100 and at least one cyclonic separator 200. A solvent
flow path 300 extends from the extraction chamber to the cyclonic separator.
In
use, botanical material (e.g. cannabis) is exposed to solvent in the
extraction
chamber, under process conditions that result in one or more compounds (e.g.,
terpenes) present in the botanical material being dissolved by the solvent and
drawn from the botanical material. Solvent containing the dissolved extracted
.. compound(s) is conveyed to the cyclonic separator via the solvent flow
path. At
the cyclonic separator 200, the extracted compound(s) are disassociated or
separated from the solvent, and the extracted compounds may then be collected
for use and/or further processing.
[00108] Extraction chamber 100 may be any extraction chamber and,
optionally, an extraction chamber useable with a condensable gas and
optionally,
an extraction chamber operable at conditions at which a condensable gas is in
a
supercritical phase.
[00109] Extraction chamber 100 has at least one botanical feedstock
port or
inlet 110. Botanical feedstock port or inlet 110 is openable to allow a
botanical
feedstock to be introduced into and/or a botanical feedstock that has been
subjected to extraction to be removed from the interior of the extraction
chamber.
For example, feedstock inlet 110 may comprise a feedstock inlet port with an
openable door 112.
- 24 -
CA 2990050 2017-12-21
[00110] In the illustrated schematic example, a single feedstock port
110 is
provided at a side of extraction chamber 100. It will be appreciated that in
alternative embodiments, two or more ports 110 may be provided (e.g., an inlet
port and a used feedstock removal port). Further, the port(s) may be placed
elsewhere (e.g., on an upper and/or lower portion of the extraction chamber).
[00111] Extraction chamber 100 also has at least one solvent inlet
through
which solvent (e.g. a condensable gas solvent) may be introduced in to the
extraction chamber. In the illustrated schematic example, a single solvent
inlet
port 120 is downstream of a source solvent. If the solvent is a condensable
gas
solvent, then port 120 may be downstream of a source of pressurized solvent.
Any source of pressurized solvent may be used. For example, a tank 60 of
pressurized gas, a pump, or another suitable pressure control device (e.g. a
diaphragm compression system). As exemplified, solvent inlet port 120 is shown
in communication with solvent pump 50, which is itself in communication with a
solvent reservoir (e.g. solvent tank 60).
[00112] If solvent is recycled, then as exemplified, a solvent return
conduit
40 may be provided through which solvent may be recycled back to the
extraction chamber (as discussed further below), either directly or through
tank
60.
[00113] It will be appreciated that in alternative embodiments, two or more
solvent inlets may be provided. For example, the downstream end of return
conduit 40 may be in communication with tank 60 or may be conveyed directly to
extraction chamber 100 (such as by a separate pump).
[00114] During operation of the extractor, solvent pump 50 or another
suitable pressure control device (e.g. a diaphragm compression system) may be
used in controlling process conditions of the solvent in the extraction
chamber.
For example, solvent pump 50 may be used to control the pressure of solvent
within the extraction chamber, which may assist in bringing solvent to a
desired
- 25 -
CA 2990050 2017-12-21
phase (e.g. liquid, supercritical fluid) and/or a desired density, and in
maintaining
solvent at a desired phase and/or desired density. Preferably, the pressure
control system allows the extraction chamber pressure to be selectively varied
across an operational range of about ambient to about 5,000 psi, and may be
from 800 to 5,000 psi, 1,000 to 4,000 psi, 1,500 to 3,500 psi and 2,000 psi to
3,000 psi. Examples of operating pressure ranges of extraction chamber 100
may be from 800 to 1,000 psi, from 1,000 to 1,200 psi, from 1,200 to 1,400
psi,
from 1,400 to 1,800 psi, from 1,800 to 2,000 psi, or from 2,000 to 4,000 psi.
[00115] Optionally, as exemplified, extraction chamber 100 may have
one
or more heat transfer members 135 that may be used to control the temperature
of the interior of the extraction chamber by adding thermal energy to and/or
removing thermal energy from, the interior of the chamber. For example, heat
transfer member 135 may include a heating jacket through which fluid may be
circulated to raise or lower the temperature of portions of the chamber wall.
Alternatively, or additionally, heat transfer member 135 may include
electrical
heat tracing bonded (e.g. directly bonded) to an exterior surface of the
extraction
chamber. As the extractor vessel may need to be heated and cooled to maintain
desired operating conditions, the use of electrical heat tracing would require
a
cooling system if the extractor is also to be cooled.
[00116] During operation of the extractor, heat transfer member 135 may be
used in controlling process conditions of e.g. solvent in the extraction
chamber.
For example, heat transfer member 135 may be used to control the temperature
of solvent within the extraction chamber, which may assist in bringing solvent
to a
desired phase (e.g. liquid, supercritical fluid) and/or a desired density, and
in
maintaining the solvent at a desired phase and/or desired density. Preferably,
heat transfer member 135 may allow the extraction chamber temperature to be
selectively varied across an operational range of from about -20 C to about
110 C and may be from 0 to 90 C, from 20 to 70 C, and from 20 - 50 C.
Examples of operating temperature ranges of extraction chamber 100 may be
- 26 -
CA 2990050 2017-12-21
from -20 C to 0 C, from 0 C to 20 C, from 20 C to 50 C, from 50 C to 110 C,
from 50 to 70 C, or from 70 to 90 C.
[00117] It will be appreciated that if the solvent is a condensable
gas
solvent, then the solvent may be introduced into extraction chamber 100 as a
liquid or in a supercritical phase, or may be changed to be a liquid or at a
supercritical phase once introduced into the extraction chamber. For example,
if
the solvent is introduced as a liquid, it may be subjected to conditions in
the
extraction chamber which result in the solvent transitioning to a
supercritical
phase.
[00118] An advantage of providing an extraction chamber that can be
operated at temperatures, e.g., from about -20 C to about 110 C and at, e.g.,
pressures of up to about 4,000 psi it that such an extraction chamber may
allow
the flexibility to run extractions across the most variable regions of the
phase
space of 002, spanning gas, liquid, and supercritical.
[00119] In some embodiments, heat transfer member 135 may also be
used to control the temperature of botanical feedstock positioned in the
extraction chamber. For example, after being introduced into the chamber,
botanical material may be cooled until some, substantially all, or all of the
water
in the botanical material transitions to a solid phase (i.e. the material may
be
frozen or partially frozen). For example, at least 50%, 60%, 70%, 80% or 90%
of
the water in the feedstock may be in a solid phase. Alternatively, botanical
material introduced into the extraction chamber in a frozen or partially
frozen
state may be maintained in such a state using heat transfer member 135.
[00120] An advantage of freezing the botanical material is that this
may
impede or prevent water in the botanical material from being dissolved by the
solvent. This may result in a more 'complete' extract being obtained, and may
also improve the speed and/or efficiency of the solvent extraction.
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CA 2990050 2017-12-21
[00121] Another advantage of freezing the botanical material is that
this
may reduce or obviate the need to desiccate the material prior to extraction.
This
may be particularly advantageous for extracting compounds (e.g., terpenes)
from
a cannabis feedstock. For example, this may allow cannabis to be harvested and
introduced into the extraction chamber without undergoing a drying process to
remove moisture from the cannabis feedstock, or only undergoing an abbreviated
drying process.
[00122] For example, cannabis having a moisture content above about
12%, or above about 9%, may be characterized as being 'fresh' or `undriedi
cannabis. As drying cannabis may be a relatively lengthy process, and may
involve a dedicated drying room or other specialized drying apparatus, the
ability
to extract compounds from 'fresh' cannabis may result in overall process
efficiencies, reduced process time, and/or cost savings.
[00123] Also, one or more compounds typically present in cannabis may
be
lost, damaged, or otherwise adversely affected during a typical drying
process.
For example, volatile terpenes and aldehydes may be considered particularly
susceptible to loss during drying. Accordingly, extractions performed with an
undried feedstock or even a feedstock that has only partially been dried may
facilitate a greater extraction and recovery of these compounds.
[00124] As exemplified in Figure 1, a conduit 30 provides a flow path for
solvent to flow from the extraction chamber 100 to the cyclonic separator 200.
As
exemplified, conduit 30 extends between a solvent outlet 130 of the extraction
chamber 100 and a fluid inlet 210 of the cyclonic separator 200.
[00125] As exemplified, one or more heat transfer members 35 may be
provided along at least a portion of the solvent flow path between solvent
outlet
130 of the extraction chamber 100 and a fluid inlet 210 of the cyclonic
separator
200. The heat transfer member 35 may be any heat transfer member used to
transfer heat between the member 35 and the solvent in the flow path.
- 28 -
CA 2990050 2017-12-21
Accordingly, the heat transfer member 35 may be used to control the
temperature of solvent by adding thermal energy to, or removing thermal energy
from, solvent flowing through the conduit.
[00126] Typically, heat is added to the solvent in the flow path to
convert
the solvent to a supercritical or gaseous phase. When the heat transfer member
35 is used to heat solvent flowing through the solvent flow path, the
location(s) at
which a heat transfer device is provided may be characterized as a 'heating
zone'.
[00127] It will be appreciated that any heat transfer member 35 may be
.. used. The heat transfer member may be a heat exchanger, such as a cross
flow
heat exchanger or an in-line heat transfer member. For example, a heating
jacket
may be provided on part of the conduit 30. Alternatively, or additionally,
heat
transfer member 35 may include electrical heat tracing bonded (e.g. directly
bonded) to an exterior surface of the conduit.
[00128] It will be appreciated that heat transfer member 35 may be located
at any location along conduit 30. Optionally, the heat transfer member 35 may
be
located towards the downstream end of conduit 30, such as one or more of
proximate fluid inlet 210 of the cyclonic separator, as part of fluid inlet
210 of the
cyclonic separator, immediately upstream of fluid inlet 210 of the cyclonic
separator, and immediately upstream of a sonic flow nozzle. An advantage of
positioning the heat transfer member 35 closer to the entrance to the cyclone
separator is that the solvent may be maintained in a liquid or supercritical
phase
for most or all of the length of conduit 30. Liquid and supercritical states
have
better solubilization characteristics than gaseous solvent. Further, when the
solvent converts to the gaseous state, extracted botanical elements, which may
be oily, may separate from the solvent and may foul conduit 30 and other parts
of
the flow path. Accordingly, maintaining the solvent in a liquid or
supercritical
phase for longer may reduce fouling of the flow path.
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[00129] It will be appreciated that one or more control valves or
other flow
control devices may be positioned in the solvent flow path to assist in
controlling
process conditions, e.g., flow rate and/or the temperature of the solvent
entering
the cyclonic separator, between the extraction chamber 100 and the cyclonic
separator 200. Additionally, or alternatively, one or more sensors, such as
temperature sensors (e.g. a thermocouple, resistive thermal device, and the
like)
and/or pressure sensors (e.g. a quartz-based sensor, electrical resonating
diaphragm, and the like) may be positioned along the solvent flow path, e.g.
to
provide data to a process control system, such as a SCADA control system or
the like.
[00130] Cyclone separator has a tangential fluid inlet 210. Any
tangential
cyclone inlet may be used. Accordingly, fluid inlet 210 may be positioned and
constructed in any manner suitable for directing solvent tangentially into
cyclone
chamber 205. Optionally, two or more tangential inlets may be spaced around
the circumference of the cyclone chamber, which may facilitate cyclonic
rotation
of solvent within the cyclone chamber.
[00131] Cyclone separator 200 may be any cyclone separator known in
the
separation arts. As exemplified in Figure 1, cyclone separator 200 has a fluid
inlet 210 and a fluid outlet 220 at the upper end of the cyclone separator 200
and
.. a separated material outlet 230 at the lower end of the cyclone separator
200. In
use, solvent may enter the cyclone chamber 205 of Figure 1 tangentially
through
the fluid inlet 210, and swirl (e.g. move cyclonically) in the cyclone chamber
to
promote separation of compounds extracted from the botanical material from the
solvent. Solvent from which the compound(s) have been separated may exit the
cyclone chamber 205 through a gas outlet 220 provided at an upper end of the
cyclone separator 200. The separated compound(s) may exit the cyclone
chamber 205 through the separated material outlet 230 provided at a lower end
of the cyclone separator.
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[00132]
Optionally, as exemplified in Figure 1, apparatus 1000 may also
include a nozzle 300 positioned adjacent (e.g., immediately upstream of or as
part of) tangential fluid inlet 210 of cyclone chamber 205. In the illustrated
example of Figure 2, tangential fluid inlet 210 is positioned directly
downstream
of (e.g., abutting) an outlet 320 of nozzle 300. Such an arrangement may allow
solvent exiting flow nozzle 300 to be directly tangentially introduced into
the
cyclonic tangential fluid inlet 210 and/or the cyclone chamber 205. In some
embodiments, the cyclonic tangential fluid inlet 210 may comprise the nozzle
300.
[00133]
Optionally, nozzle 300 accelerates the solvent passing
therethrough (such as a convergent nozzle) and may be a sonic flow nozzle
(such as a converging-diverging nozzle). In alternative embodiments, flow
nozzle
300 may comprise an orifice plate. A cross-section of an example of a nozzle
300
is illustrated in Figure 3. As exemplified, nozzle 300 has an inlet end 310
and an
outlet end 320. The internal diameter of the nozzle narrows in the direction
of
flow, from an inlet diameter 315 at the inlet end to a smaller diameter 335 at
the
nozzle throat 330. Downstream of the throat 330, the diameter increases. As
exemplified, the wall 340 at the outlet of the throat 330 is generally
transverse to
the direction of flow through the nozzle. The diameter of the nozzle therefore
immediately increases to a diameter 325 which is larger than throat diameter
335
and may be about the same as inlet diameter 315. It will be appreciated that
wall
340 may extend in the direction of flow at an angle of less than 90 (which is
exemplified in Figure 3). Fluid exiting throat 330 expands at a dispersion
angle A
of from 90 to 70 , from 85 to 70 , from 80 to 70 , or from 75 to 70 .
[00134] The
nozzle 300 may be positioned and configured such that fluid
exiting outlet 320 of nozzle 300 may enter into the cyclone chamber without
impinging on an interior wall 345 of the downstream part of nozzle 300 and/or
tangential fluid inlet 210. Alternatively, fluid may only impinge on a
downstream
part of the interior wall 345 of the downstream part of nozzle 300 and/or the
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tangential fluid inlet 210. For example, the dispersion angle A may be
selected
such that fluid exiting nozzle 320 will not impinge upon the wall of the
tangential
inlet. It will be appreciated that wall 345 may define part or all of the
tangential
inlet. An advantage of design is that separation of compound(s) from the
solvent
in the flow stream downstream of throat 330 may reduce or prevent an
accumulation of separated compounds within the nozzle and/or tangential inlet.
[00135] In use, the apparatus is preferably operated under process
conditions in which the nozzle operates in a 'choked' state. For example, a
ratio
of the pressure of the fluid entering the nozzle inlet (which may be referred
to as
the "nozzle inlet pressure" or "upstream pressure") and the pressure of the
fluid
exiting the nozzle outlet (which may be referred to as the "nozzle outlet
pressure"
or "downstream pressure") is preferably greater than 1.4 and may be from 1.4:1
to 14.2:1, from 1.4:1 to 7.2:1, from 4.2:1 to 14.2:1. Examples of operating
ranges
that may be used are 1.4:1 to 4.2:1, from 4.2:1 to 7.2:1, from 7.2:1 to
14.2:1. An
advantage of operating the flow nozzle under 'choked' conditions is that the
mass
flowrate through the nozzle is only influenced by the upstream pressure and
upstream temperature (i.e. density) of fluid entering the nozzle. Accordingly,
upstream pressure disturbances (e.g. pressure pulsation due to pumps, flow
fluctuations as a result of extraction, etc.) may be inhibited or prevented
from
moving downstream past the nozzle 300 and into the cyclonic separator, and
thus may be inhibited or prevented from causing undesirable pulsations and/or
vortex flow instabilities during the decompression and/or separation that
occurs
in the cyclonic separator.
[00136] By providing a sonic flow nozzle 300, solvent passing through
the
nozzle may enter the cyclone chamber at sonic or supersonic velocity. An
advantage of this design is that the radial acceleration resulting from the
solvent
being rotated in the cyclone chamber while travelling at sonic or supersonic
velocities may be more effective at promoting disassociation (i.e. separation)
of
extracted compound(s) from the solvent, as compared to sub-sonic flow. For
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example, in typical gas-liquid cyclonic separators (e.g. with sub-sonic fluid
injection), there may be significant 'carry over' of entrained product exiting
the
separator along with the solvent exiting the cyclone outlet, which may lead to
fouling of e.g. low pressure piping and compression pumps positioned
downstream of the cyclone gas outlet. Further, the separated material tends to
be foamed with entrained solvent as exemplified in Figure 8.
[00137] Optionally, as exemplified in Figure 1, the cyclone separator
200
includes a temperature control system, which in the illustrated example is
shown
as a heat transfer member 235 such as a heat jacket 235. Alternatively, or
additionally, heat transfer member 235 may include electrical heat tracing
bonded (e.g. directly bonded) to an exterior surface of the cyclone separator
200.
Heating jacket 235 may be used to convey thermal energy to the interior wall
215
of the cyclone chamber 205. Heating the cyclone chamber may have one or
more advantages. For example, compounds separated from the solvent in the
cyclone separator that come into contact with the interior wall of the cyclone
separator may thereby be heated, which may reduce the viscosity of the
separated compounds. An advantage of reducing the viscosity of the separated
compounds is that they may more easily and/or rapidly flow down the walls of
the
cyclone separator (due to gravity) to a collection chamber, such as collection
chamber 240.
[00138] Separated material exiting separated material outlet 230 may
be
collected in any manner known in the separation arts. As exemplified in Figure
1,
a separated material collection chamber 240 in communication with the
separated materials outlet 230 of cyclonic separator 200 may be provided to
receive compounds disassociated (i.e. separated) from solvent entering fluid
inlet
210 of the cyclonic separator 200.
[00139] Preferably, the separated material collection chamber 240 is
removable from the cyclonic separator 200. Providing a detachable separated
material collection chamber 240 may allow a user to transport (e.g. carry) the
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collected separated material (e.g. compound(s) extracted from cannabis) to
another location for emptying and/or further processing, without needing to
carry
or move the cyclonic separator 200. Preferably, the separated material
collection
chamber 240 is removable as a closed module, which may help prevent the
extracted compounds from spilling out of the separated material collection
chamber 240 during transport.
[00140] Alternatively, the separated materials outlet 230 may be in
flow
communication with (connected or removably connected to) a conduit which
transports the separated compound(s) to, e.g., another piece of equipment for
further processing.
[00141] As exemplified in Figure 1, a gas return conduit 40 may
optionally
be provided between a gas outlet 220 of the cyclone separator and a solvent
inlet
120 to the extraction chamber 100. An advantage of this design is that it may
allow the gas solvent to be recycled to the extraction chamber 100 after
extracted
compounds have been disassociated from the solvent in the cyclone chamber.
This may be characterized as a 'closed-loop' system. Optionally, one or more
gas pumps 55 or other flow control devices may be provided to re-pressurize
the
solvent prior to its reintroduction to the extraction chamber and/or a storage
tank,
such as tank 60. An advantage of recycling solvent (e.g. 002) is that such a
closed loop system may reduce solvent usage, and may therefore be
characterized as a low consumption, environmentally friendly, and/or 'green'
process. Alternatively, such a solvent recycling system may not be provided,
and
solvent exiting the cyclone separator may be expelled or stored, without being
recycled back to the extraction chamber.
[00142] In one embodiment, the apparatus includes both a heat transfer
member 35 and a nozzle 330. The heat transfer member 35 is located
immediately upstream from nozzle 300. Accordingly, solvent entering the nozzle
300 may be gaseous. An advantage of this design is that the solvent may be
maintained in a liquid or supercritical phase until just before it enters
nozzle 300
- 34 -
CA 2990050 2017-12-21
and may then enter the cyclone chamber with no or only minimal impingement on
the wall of the flow path downstream of nozzle 300, thereby limiting or
preventing
the fouling of the flow path downstream of nozzle 300.
General description of a method for extracting compounds from botanical
material using a condensable gas solvent
[00143] The flowing is a description of a method for extraction which
may
be used by itself or in combination with one or more of the other features
disclosed herein including the use of any of the features of the apparatus
and/or
and any of the methods disclosed herein.
[00144] Referring to Figure 6, there is illustrated a method 500 for
extracting compounds from botanical material using a condensable gas solvent.
Method 500 may be performed using apparatus 1000 or any other suitable
apparatus for the extraction of compounds from a botanical material. Figure 6
exemplifies a method in which a single extraction operation is conducted and a
single cyclone separator is used. As discussed herein, the same feedstock may
be subjected to two or more extraction operations, which may be conducted at
the same conditions or at different conditions, and each extraction operation
may
use the same solvent or a different solvent. Further, as also discussed
herein, an
extraction operation or a series of extraction operations, may use two or more
cyclone separators. It will be understood that the method exemplified in
Figure 6,
with any one or more of the optional steps, may be used with a method
employing multiple extraction steps and/or multiple cyclone separators.
[00145] At 505, in an extraction chamber, such as extraction chamber
100,
a condensable gas solvent is used to extract at least one compound from a
feedstock of botanical material. For example, the botanical material (e.g.
cannabis) may be introduced into chamber 100 through a feedstock inlet 110
provided at the end of chamber 100. Once the botanical material has been
introduced and the feedstock inlet closed, a condensable gas solvent (e.g.
carbon dioxide) may be introduced into the extraction chamber, and process
- 35 -
CA 2990050 2017-12-21
conditions within the extraction chamber (pressure, temperature, etc.) may be
controlled so that the botanical material is exposed to solvent at a
predetermined
state (phase, density, temperature, pressure, etc.) for a predetermined time,
during which one or more compounds present in the botanical material are
dissolved by the solvent and extracted from the botanical material. It will be
appreciated that the condensable gas may be introduced into chamber 100 at the
predetermined state and the conditions in chamber 100 may maintain the
condensable gas in the predetermined state. The extraction chamber may be at
any pressure and temperature discussed herein
[00146] The
condensable gas may be used to extract one or more
compounds from the feedstock. Optionally, if the botanical material is
cannabis,
compounds extracted by the solvent may include one or more of an aliphatic
aldehyde (e.g. nerol, geraniol, octanal, decanal), a terpene (e.g. limonene,
pinenes, ocimenes), and a cannabinoid.
[00147]
Optionally, in any embodiment, a fresh feedstock of cannabis may
be obtained and introduced into extraction chamber 100. For example, cannabis
may be harvested and introduced into the extraction chamber without undergoing
a drying process to remove moisture from the cannabis feedstock.
[00148]
Optionally, in any embodiment, a cannabis feedstock (fresh or
dried) may be comminuted prior to being introduced into the extraction chamber
in order to increase the surface area of the botanical material.
[00149]
Optionally, in any embodiment, a feedstock of fresh cannabis may
be provided to an extraction chamber where water in the feedstock is in a
solid
phase (which may be characterized as frozen or partially-frozen cannabis).
Alternatively, unfrozen cannabis may be provided to extraction chamber 100,
and
the temperature of the extraction chamber 100 brought to and/or maintained at
a
temperature below the freezing point of water (e.g. using heat transfer member
135) until water in the feedstock transitions to the solid phase.
- 36 -
CA 2990050 2017-12-21
[00150] Optionally, in any embodiment, condensable gas solvent in the
extraction chamber may be brought to and/or maintained in at least one of a
liquid phase and a supercritical phase, and used to extract at least one
compound from the cannabis while in a liquid and/or supercritical phase. For
example, process conditions within the extraction chamber (pressure,
temperature, etc.) may be controlled so that solvent in a liquid phase and/or
in a
supercritical phase contacts the botanical feedstock for a predetermined time,
during which one or more compounds present in the feedstock are dissolved by
the solvent and extracted from the feedstock.
[00151] At 510, solvent containing the dissolved or extracted one or more
compounds is withdrawn from the extraction chamber and the solvent (which
may be characterized as a 'solvent stream') is then conveyed through a solvent
flow path to a separator. For example, solvent may be withdrawn from
extraction
chamber 100 via solvent outlet port 130, and conveyed to fluid inlet 210 of
cyclonic separator 200 through solvent conduit 30.
[00152] Optionally, at 515, at least some solvent may be converted to
a
gaseous phase upstream of the cyclone chamber. For example, the solvent
stream may be heated prior to entering the separator. For example, heating
jacket 35 or another heating member may be used to heat solvent as it passes
through the solvent flow path. Heating the solvent may cause some, a
substantial
portion of, or all (e.g., more than 50%, 60%, 70%, 80%, or 90%) of the solvent
in
a liquid phase to transition to a gaseous phase and/or to a supercritical
phase.
[00153] Alternatively, or additionally, the pressure of the solvent
stream
upstream of the cyclone chamber may be lowered, e.g. via one or more control
valves positioned in the solvent flow path. Reducing the pressure of the
solvent
stream may cause some, a substantial portion of, or all (e.g., more than 50%,
60%, 70%, 80%, or 90%) of any liquid solvent to transition to a supercritical
and/or gaseous phase. Also, reducing the pressure may cause some, a
- 37 -
CA 2990050 2017-12-21
substantial portion of, or all (e.g., more than 50%, 60%, 70%, 80%, or 90%) of
any supercritical solvent to transition to a gaseous phase.
[00154] Optionally, at 520, solvent traveling at sonic or supersonic
velocity
may be obtained. For example, a sonic flow nozzle 300 may be positioned in the
solvent flow path upstream of the fluid inlet to the cyclone chamber, and the
nozzle inlet pressure, nozzle outlet pressure, and/or nozzle backpressure may
be
adjusted so that most or substantially all of the solvent exits the sonic flow
nozzle
at sonic or supersonic velocity. Advantageously, this may allow solvent to be
directed into a cyclone chamber at sonic or supersonic velocity. Optionally,
the
solvent may be heated immediately upstream of the nozzle 300.
[00155] At 525, some, or preferably most, or more preferably
substantially
all of the extracted compound(s) is separated from the solvent. For example,
the
solvent stream may be directed into a cyclonic separator, such as cyclonic
separator 200.
[00156] Preferably, solvent is introduced tangentially into a cyclone
separator, e.g. via a tangential cyclone inlet, such as tangential cyclone
inlet 210.
Optionally, if a nozzle 300 is utilized, the nozzle may be positioned
immediately
upstream of a tangential cyclone inlet or nozzle 300 may be the tangential
cyclone inlet. Accordingly, solvent may be introduced directly into the
cyclone
separator, i.e. without being directed through a conduit or the like between a
nozzle outlet and the cyclone separator. For example, the outlet of the nozzle
300 may be positioned adjacent the cyclone separator, and solvent exiting the
sonic flow nozzle may be directed so as to avoid contacting sidewalls of a
conduit downstream of the nozzle 300 and/or an inlet port of the cyclone
separator.
[00157] As another example, the outlet of the sonic flow nozzle may be
positioned at an inlet port of the cyclone separator, and solvent exiting the
sonic
- 38 -
CA 2990050 2017-12-21
flow nozzle may be conveyed immediately into the cyclone separator so as to
avoid contacting the inlet port of the cyclone separator.
[00158] An advantage of introducing solvent directly into the cyclone
separator when the solvent has been converted to a gaseous state is that it
may
inhibit fouling of the sidewalls of a conduit downstream of the nozzle 300 by
an
extract that is liberated from the solvent when it becomes gaseous.
[00159] Optionally, at 530, some, or preferably most, or more
preferably
substantially all of the at least one compound dissolved in the solvent may be
separated in the cyclone separator and collected as an unfoamed liquid as
exemplified in Figure 9. For example, if the botanical material is cannabis,
compounds separated from the solvent in the cyclone separator may include one
or more of an aliphatic aldehyde, a terpene, and a cannabinoid.
[00160] An advantage of collecting the separated at least one compound
as
an unformed liquid is that the collected liquid may be easier to work with
and/or
easier to post-process.
[00161] Optionally, at 535, the cyclone separator may be heated. For
example, a temperature control system such as heating jacket 235 or the like
may be used to convey thermal energy to the interior wall of the cyclone
separator during operation of the cyclone separator. The cyclone separator may
be heated to raise the temperature of the cyclone chamber to a predetermined
temperature prior to the separation operation. Alternately or in addition, the
temperature control system may be used to maintain the temperature of the
cyclone chamber at a predetermined temperature during operation. For example,
if a sonic flow nozzle is utilized, the expansion of the solvent may cool the
solvent
stream which enters the cyclone chamber. The temperature control system may
partially or fully counter the cooling effect of the flow through a sonic flow
nozzle
and may therefore enable the cyclone separator to operate at a design
temperature or temperature range. Thus, compounds separated from the solvent
- 39 -
CA 2990050 2017-12-21
in the cyclone separator may thereby be heated or maintained at a design
temperature or temperature range, which may reduce the viscosity of the
separated compounds. An advantage of reducing the viscosity of the separated
compounds is that they may more easily and/or rapidly flow down the walls of
the
cyclone separator (due to gravity) to a collection chamber, such as collection
chamber 240.
Apparatus for the extraction of compounds from botanical material with
multiple cyclonic separation stages
[00162] Referring to Figure 5, an exemplary embodiment of another
apparatus for the extraction of compounds from botanical material is shown
generally as 2000. Elements having similar structure and/or performing similar
function as those in the example apparatus illustrated in Figures 1 to 4 are
numbered similarly, and will not be discussed further. As exemplified therein,
an
extraction and separation operation may use two or more cyclone separators.
[00163] As exemplified in Figure 5, apparatus 2000 includes an extraction
chamber 100, a first cyclonic separator 200A, a second cyclonic separator
200B,
and a third cyclonic separator 200C. While in the illustrated example three
cyclonic separators are shown, in alternative embodiments apparatus 2000 may
have only two cyclonic separators, or four or more cyclonic separators may be
provided.
[00164] Providing an apparatus 2000 with two or more cyclonic
separators
in parallel may have one or more advantages. For example, each cyclone
separator may be configured to disassociate different compounds from a solvent
flow. For example, different cyclone separators may be configured to induce
different rotational velocities. Higher rotational velocity may be used to
separate
smaller droplets of liquid or smaller particles containing higher molecular
weight
compounds which may be separated from a flow stream of solvent in a cyclone.
Accordingly, a first cyclone separator may produce a lower rate of rotation of
solvent which will result in heavier (larger) droplets of liquid or larger
heavier
- 40 -
CA 2990050 2017-12-21
particles being separated than in a second stage cyclone operating at a higher
rotational speed. However, the velocity in the first cyclone separator may be
insufficient to disentrain lighter (smaller) droplets of liquid or lighter
compounds.
A second downstream cyclone separator may be operated to produce a higher
rotational velocity, which may remove the lighter (smaller) droplets of liquid
or
lighter compounds. Providing the ability to selectively direct solvent from
the
extraction chamber to one of two or more cyclonic separators, which may be in
series, may facilitate a more complete disassociation of extracted compound(s)
from solvent, as solvent containing particular compound(s) can be directed to
a
separator best suited to disassociate that compound(s). For example, the
solvent
stream may be sequentially directed though the two or more cyclones (e.g.,
they
may be operated in series). Alternately, different extraction operations may
be
conducted to selectively remove certain compounds from a feedstock. Therefore,
one extraction operation may produce a solvent having heavier compounds and
a second extraction operation may produce a solvent having lighter compounds.
The solvent from each extraction operation may be directed to a differently
configured cyclone (e.g., each cyclone may be configured to separate
compounds targeted by a particular extraction operation).
[00165] Returning to Figure 5, in use, botanical material (e.g.
cannabis)
.. may be exposed to solvent in the extraction chamber 100 under a first set
of
process conditions to preferentially extract a first set of one or more
compounds
present in the botanical material from the botanical material. Solvent
containing
the first extracted compound(s) may be conveyed to the first cyclonic
separator
200A, where the first extracted compound(s) are disassociated from the
solvent.
.. Subsequently, the botanical material may be exposed to the same or a
different
solvent in the extraction chamber 100 under a second set of process conditions
to preferentially extract a second set of one or more compounds from the
botanical material. Solvent containing the second extracted compound(s) may
then be conveyed to the second cyclonic separator 200B, where the second
-41 -
CA 2990050 2017-12-21
extracted compound(s) are disassociated from the solvent. Optionally, the
botanical material may subsequently be exposed to solvent in the extraction
chamber 100 under a third set of process conditions to preferentially extract
a
third set of one or more compounds from the botanical material. Solvent
containing the third extracted compound(s) may then be conveyed to the third
cyclonic separator 2000, where the third extracted compound(s) are
disassociated from the solvent.
[00166] Preferably, each cyclonic separator may be configured based on
the extracted compound(s) expected to be in the solvent flow, which may result
in a more thorough and/or efficient disassociation or separation of the
compounds from the solvent. For example, if a first set of process conditions
of
the extractor is designed to preferentially target one or more high-molecular
weight compounds for extraction, the first cyclonic separator may be
configured
to optimize the removal of higher molecular weight compounds from solvent.
Similarly, if a second set of process conditions of the extractor is designed
to
preferentially target one or more lower-molecular weight compounds for
extraction, the second cyclonic separator may be configured to optimize
removal
of lower molecular weight compounds from solvent. For example, during
separation, solvent in cyclone chamber 205A of cyclone separator 200A may
rotate at a first speed, and solvent in cyclone chamber 205B of cyclone
separator
200B may rotate at a second, different speed.
[00167] For example, if the botanical material is cannabis and the
extraction
chamber is operated under a set of process conditions to preferentially
extract
one or more waxes from the cannabis, solvent containing the one or more
extracted waxes may be directed to a cyclonic separator that is operated at
pressure conditions to separate this class of compounds. For example, under
extraction conditions that result in a high CO2 density (which may be any
combination of pressure and temperature that results in the CO2 being in a
high
density state, such as over 0.85g/cm3), waxes may be solubilized and
extracted.
- 42 -
CA 2990050 2017-12-21
Solvent containing the waxes may be directed to one or more separators wherein
the CO2 is expanded to drop out the solute and the gaseous CO2 which is
obtained may be returned to a compression system and recycled into the
extractor.
[00168] If the extraction chamber is operated under a set of process
conditions to preferentially extract one or more light oils from the cannabis,
solvent containing the one or more extracted light oils may be directed to a
cyclonic separator to expand and deposit the solute and return the
decompressed CO2 back to, e.g., a pump for recompression and recycle into the
extractor. For example, lighter compounds may be selectively extracted by
using
the CO2 in a low density supercritical state, for example, the density of the
solvent may be between 0.25 to 0.35 g/cm3. Such density conditions may be
obtained using a number of combinations of pressure and temperature, with the
caveat that the temperature be above the critical temperature of 31.1 C,
preferably greater than 33 C to avoid critical point instabilities.
[00169] It will be appreciated that the lighter oils and the waxes may
be
sequentially extracted. In such a case, the extraction operations are
optionally
conducted so as to initially extract the lighter molecular weight compounds
(e.g.,
the lighter oils) and to then extract the heavier molecular weight compounds
(e.g., the waxes). The solvent from the lighter oil extraction operation may
be
directed to one or more cyclone separators that operate in parallel and which
are
designed to separate the lighter oils from the solvent. The solvent from the
wax
extraction operation may be directed at one or more cyclone separators that
operate in parallel and which are designed to separate the waxes from the
solvent.
[00170] Alternatively, a plurality of cyclone stages may be provided
in
series, wherein each cyclone stage may comprise one or more cyclone
separators operating in parallel. The solvent from each extraction stage may
be
directed sequentially through the plurality of cyclone stages. In such a case,
the
- 43 -
CA 2990050 2017-12-21
first stage cyclone separator(s) may be designed to separate the heavier
compounds (e.g., compounds having a heavier molecular weight) and the
second stage cyclone separator(s) may be designed to separate the lighter
compounds (e.g., compounds having a lighter molecular weight). It will be
appreciated that three or more cyclone stages may be employed, each using one
or more cyclone separators in parallel, wherein each stage recovers lighter
compounds than the previous stage.
[00171] In an alternative use of apparatus 2000, botanical material
(e.g.
cannabis) may be exposed to solvent in the extraction chamber 100 under a set
of process conditions to extract a relatively large range of compounds, and
solvent containing the extracted compound(s) may be conveyed to the first
cyclonic separator 200A to preferentially disassociate a first set of
compounds
from the solvent. Next, while the extraction chamber may still being operated
under the same set of process conditions, solvent containing the extracted
compound(s) may subsequently be conveyed to the second cyclonic separator
200B to preferentially disassociate a second set of compounds from the
solvent.
[00172] In the illustrated example, a conduit 32 provides a path for
solvent
to flow from the extraction chamber 100 to a valve 80. Valve 80 may be used to
selectively direct solvent from conduit 32 to first cyclonic separator 200A
(via
conduit 34), second cyclonic separator 200B (via conduit 36), or third
cyclonic
separator 2000 (via conduit 38). Alternative embodiments may include different
solvent flow paths and/or valve configurations. For example, in the
illustrated
example, conduit 32 is common to the solvent flow paths from the extraction
chamber to each cyclonic separator, and may therefore be characterized as a
common solvent flow path portion. Alternatively, apparatus 2000 may not have a
common solvent flow path portion, e.g. by providing separate dedicated
conduits
from the extraction chamber to each cyclonic separator, wherein each conduit
may have an associated valve to selectively direct solvent flow from the
extractor
to its respective cyclonic separator.
- 44 -
CA 2990050 2017-12-21
[00173] As with the embodiment of Figures 1-4, an optional heat
transfer
device 35 and/or nozzle 300 may be provided along at least a portion of one or
more and optionally each solvent flow path, providing each solvent flow path
with
a 'heating zone', as discussed above.
[00174] It will be appreciated that one or more control valves or other
flow
control devices may be positioned in the solvent flow paths to assist in
controlling
process conditions between the extraction chamber 100 and each cyclonic
separator 200A, 200B, 2000. Additionally, or alternatively, one or more
sensors,
such as temperature sensors (e.g. a thermocouple, resistive thermal device,
and
the like) and/or pressure sensors (e.g. a quartz-based sensor, electrical
resonating diaphragm, and the like) may be positioned along the solvent flow
path(s), e.g. to provide data to a process control system.
[00175] As with the embodiment of Figures 1-4, apparatus 2000 may also
include flow nozzles 300A, 300B, and 300C positioned adjacent the fluid inlet
210A, 210B, and 210C of each cyclone separator 200A, 200B, 200C,
respectively. Preferably, each flow nozzle 300 is configured to allow solvent
exiting that flow nozzle to be directly tangentially introduced into its
corresponding cyclone chamber. Each flow nozzle 300A, 300B, and 3000 may
be a sonic flow nozzle, such as a convergent nozzle or a converging-diverging
nozzle, or an orifice plate or other nozzle.
[00176] As exemplified in Figure 5, separated material collection
chambers
240A, 240B, 240C are shown in communication with the separated materials
outlets 230A, 230B, 2300 of cyclonic separators 200A, 200B, 2000,
respectively,
to receive compounds disassociated (i.e. separated) from solvent using each
.. cyclonic separator.
[00177] Preferably, each separated material collection chamber 240A,
240B, 2400 is removable from its respective cyclonic separator 200A, 200B,
2000 (e.g. as a closed module). Alternatively, one or more of the separated
- 45 -
CA 2990050 2017-12-21
materials outlets 230A, 230B, 2300 may each be in flow communication with a
conduit which transports the separated compound(s) to, e.g., another piece of
equipment for further processing.
General description of another method for extracting compounds from
botanical material using a condensable gas solvent
[00178] The flowing is a description of a method for extraction which
may
be used by itself or in combination with one or more of the other features
disclosed herein including the use of any of the features of the apparatus
and/or
and any of the methods disclosed herein. The method may be conducted using a
solvent stream obtained from any extraction process.
[00179] Referring to Figure 7, there is illustrated a method 600 for
extracting compounds from botanical material using apparatus comprising an
extraction chamber, a first cyclonic separation stage comprising at least one
cyclonic separator, and a second cyclonic separation stage comprising at least
one cyclonic separator. Method 600 may be performed using apparatus 2000 or
any other suitable apparatus for the extraction of compounds from a botanical
material.
[00180] At 605, a feedstock of botanical material is introduced to an
extraction chamber. For example, a feedstock of cannabis may be introduced to
extraction chamber 100 through a feedstock inlet 110 of chamber 100. As
discussed above, optionally a fresh feedstock of cannabis (e.g. cannabis
having
a moisture content of about 9% or about 12%, such as harvested cannabis that
has not undergone a drying process) may be provided. Optionally, the botanical
material may be comminuted prior to being introduced into the extraction
chamber in order to increase the surface area of the botanical material.
Optionally, the botanical feedstock may be introduced to the extraction
chamber
in a frozen or partially-frozen state. It will be appreciated that any
extraction
process and any extraction equipment may be used.
- 46 -
CA 2990050 2017-12-21
[00181] At 610, the extraction chamber is operated using a first
solvent
under a first set of process conditions to preferentially extract a first
compound or
compounds from the feedstock. For example, a condensable gas solvent (e.g.
carbon dioxide) may be introduced into the extraction chamber, and a first set
of
process conditions within the extraction chamber (pressure, temperature, etc.)
may be controlled so that the botanical material is exposed to first solvent
at a
predetermined state (phase, density, temperature, pressure, etc.) for a
predetermined time, during which a first compound present in the feedstock is
preferentially dissolved by the solvent and drawn from the botanical
feedstock.
[00182] For example, where the botanical feedstock includes cannabis,
compounds targeted for selective extraction may include one or more aliphatic
aldehydes, one or more terpenes, and one or more cannabinoids.
[00183] For example, to preferentially extract a lower molecular
weight
class of compounds using CO2 solvent, the first set of process conditions may
operate in the supercritical region of the solvent (e.g. a temperature of
about
40 C, and a pressure of about 1200 psi), resulting in a CO2 density that
favors
low weight compounds.
[00184] The first compound or compounds preferentially extracted at
610
may be characterized as a 'target' or 'selected' compound(s) of a first
'targeted'
or 'selective' extraction. It will be appreciated that, while the first
solvent / set of
process conditions are selected so as to preferentially extract the first
'target'
compound, one or more additional compounds may nonetheless be extracted
from the feedstock during the first selective extraction.
[00185] At 615, first solvent containing the first extracted compound
is
conveyed from the extraction chamber to the first cyclonic separation stage.
For
example, first solvent may be withdrawn from extraction chamber 100 and
directed along conduit 32, valve 80, and =conduit 34 to first cyclonic
separator
200A.
- 47 -
CA 2990050 2017-12-21
[00186] At 620, some, or preferably most, or more preferably
substantially
all of the first targeted compound(s) is separated from the first solvent in
the first
cyclonic separation stage. For example, the first solvent may be directed into
a
cyclone chamber 205A of the first cyclonic separator, and the first compound
may be separated from the first solvent and collected via outlet 230A.
[00187] Optionally, at 625, first solvent exiting the first cyclonic
separation
stage may be recycled to the extraction chamber as discussed previously. For
example, first solvent exiting cyclonic separator 200A may be directed through
conduits 42 and 40 and re-introduced to extraction chamber 100.
[00188] At 630, the extraction chamber is operated using a second solvent
under a second set of process conditions to preferentially extract a second
compound or compounds from the feedstock. The second solvent may be the
same as the first solvent, or a different solvent may be used.
[00189] For example, to preferentially extract a higher molecular
weight
class of compounds using CO2 solvent, the second set of process conditions
may also operate in the supercritical region of the solvent, but at a higher
pressure (e.g. a temperature of about 40 C, and a pressure of about 3,500
psi),
resulting in a CO2 density that approaches that of the liquid state of CO2 and
favours higher weight compounds. Thus, higher molecular weight compounds
can be effectively solvated and extracted.
[00190] Alternative solvents to CO2 can be utilized to favor the
extraction of
component that are more hydrophilic. For example, using nitrous oxide as a
solvent (either on its own or as a co-solvent with 002) the dipolar nature of
the
nitrous oxide generates a bias to compounds exhibiting dipolar-like regions on
their chemical structure. Alternatively, if one wants to select for highly
hydrophobic compounds, condensable hydrocarbons (e.g., propane, ethane)
may be used as a solvent, to avoid the extraction of compounds displaying
hydrogen bonding or ones containing areas of large charge distribution.
- 48 -
CA 2990050 2017-12-21
[00191] The second compound or compounds preferentially extracted at
630 may be characterized as a 'target' or 'selected' compound(s) of a second
'targeted' or 'selective' extraction. It will be appreciated that, while the
second
solvent / set of process conditions are selected so as to preferentially
extract the
second 'target' compound, one or more additional compounds may nonetheless
be extracted from the feedstock during the second selective extraction.
[00192] At 635, second solvent containing the second extracted
compound
is conveyed from the extraction chamber to the second cyclonic separation
stage. For example, second solvent may be withdrawn from extraction chamber
.. 100 and directed along conduit 32, valve 80, and conduit 36 to second
cyclonic
separator 200B.
[00193] At 640, some, or preferably most, or more preferably
substantially
all of the second targeted compound(s) is separated from the second solvent in
the second cyclonic separation stage. For example, the second solvent may be
directed into a cyclone chamber 205B of the second cyclonic separator 200B,
and the second compound may be separated from the second solvent and
collected via outlet 230B.
[00194] Optionally, at 645, second solvent exiting the second cyclonic
separation stage may be recycled as discussed previously to the extraction
chamber. For example, second solvent exiting cyclonic separator 200B may be
directed through conduits 44, 42, and 40 and re-introduced to extraction
chamber
100.
[00195] It will be appreciated that, as discussed previously, a
plurality of
cyclone stages may be provided in series, wherein each cyclone stage may
comprise one or more cyclone separators operating in parallel and each stage
is
designed to remove sequentially lighter extracted compounds.
[00196] Preferentially extracting different compounds from the
feedstock
during two or more selective extractions and separations may have one or more
- 49 -
CA 2990050 2017-12-21
advantages. For example, this may provide the ability to fractionate groups of
extracted components (e.g. waxes, heavy oils, and light oils) from a single
feedstock of botanical material (e.g. cannabis), without having to load/unload
the
extraction chamber (e.g. during a single 'extraction cycle').
[00197] Additionally,
the cyclonic separation stages may each be
configured or 'tuned' to preferentially separate certain selected/targeted
compound(s) from solvent. This may allow solvent containing targeted
compound(s) to be directed from the extraction chamber to a cyclonic separator
best suited to disassociate those compound(s) from solvent. The selective
extraction and separation of a greater number of compound(s) may simplify
subsequent downstream separations and/or purifications to obtain pure
compound isolates.
[00198] As used
herein, the wording "and/or" is intended to represent an
inclusive - or. That is, "X and/or Y" is intended to mean X or Y or both, for
example. As a further example, "X, Y, and/or Z" is intended to mean X or Y or
Z
or any combination thereof.
[00199] While the
above description describes features of example
embodiments, it will be appreciated that some features and/or functions of the
described embodiments are susceptible to modification without departing from
the spirit and principles of operation of the described embodiments. For
example,
the various characteristics which are described by means of the represented
embodiments or examples may be selectively combined with each other.
Accordingly, what has been described above is intended to be illustrative of
the
claimed concept and non-limiting. It will be understood by persons skilled in
the
art that other variants and modifications may be made without departing from
the
scope of the invention as defined in the claims appended hereto. The scope of
the claims should not be limited by the preferred embodiments and examples,
but should be given the broadest interpretation consistent with the
description as
a whole.
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