Note: Descriptions are shown in the official language in which they were submitted.
WO 2022/213215
PCT/CA2022/050551
1
EXTRACTING FIBRES FROM FIBRE FEEDSTOCK
TECHNICAL FIELD
[0001]
This relates to extracting natural fibres from a fibre feedstock, and
in particular using
reactive oxidizing agents in water.
BACKGROUND
[0002]
Hemp is a well-known source of fibre that may be used as a textile.
However, to be
useful, the natural glue-like compounds that bind the fibres together in the
hemp stalks must be
removed. This may be referred to as "degumming". Traditionally, this is done
using a mechanical
separation, but the process may also be accomplished by other means. United
States patent no.
8,591,701 (Sung et al.) entitled "Extraction of Hemp Fibres" describes an
example of an extraction
process that uses various chemicals in a water bath. Other sources of natural
fibre, such as flax,
may also require processing to extract the desired fibres.
SUMMARY
[0003]
According to an aspect, there is provided a method of extracting
natural fibres from
fibre feedstock, the fibre feedstock comprising gum between the natural
fibres, the method
comprising introducing fibre feedstock into water; introducing a first
oxidizing agent into the water
and causing the first oxidizing agent to partially react with the gum;
selectively introducing a
second oxidizing agent into the water to react with the partially reacted gum,
the second oxidizing
agent being more reactive than the first oxidizing agent, and removing
released fibres from the
water.
[0004]
According to other aspects, the method may comprise one or more of the
following
features, alone or in combination: the fibre feedstock may be contained within
a water-permeable
container placed in a tank filled with water, and may further comprise the
step of agitating the fibre
feedstock in the water by rotating the container; the first oxidizing agent my
comprise oxygen,
ozone, or a mixture of oxygen and ozone; the first oxidizing agent may be
introduced using a
manifold, a diffusion apparatus, or combinations thereof; the second oxidizing
agent may comprise
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
2
hydroxyl radicals; introducing hydroxyl radicals may comprise generating the
hydroxyl radicals
in the water; wherein selectively introducing the second oxidizing agent may
comprise
concentrating the hydroxyl radicals in a limited volume of the tank; the
second oxidizing agent
may be introduced into the water after the reactive oxygen generates reaction
products; the method
may comprise the step of exposing the fibre feedstock to UV light, to
ultrasonic energy, or
combinations thereof; and the method may further comprise the step of removing
the gases and
dissolved gases from the water by selectively injecting compressed air into
the water.
[0005] According to an aspect, there is provided an apparatus for
extracting natural fibres from
fibre feedstock that comprises gum between the natural fibres, comprising a
tank that contains
water, the tank being capable of receiving the fibre feedstock, an agitator
for agitating the fibre
feedstock in the water, a source of a first oxidizing agent, a source of a
second oxidizing agent,
wherein the second oxidizing agent is more reactive than the first oxidizing
agent, a controller that:
controls the source of the first oxidizing agent to introduce the first
oxidizing agent into the water,
the first oxidizing agent being capable of partially reacting with the gum of
the fibre feedstock,
and selectively controls the source of the second oxidizing agent to introduce
the second oxidizing
agent into the tank to react with the partially reacted gum.
[0006] According to other aspects, the apparatus may comprise one
or more of the following
features, alone or in combination: the fibre feedstock may be contained within
a water permeable
container within the tank, and the agitator comprises an actuator that rotates
the container; the first
oxidizing agent may comprise oxygen, ozone, or a mixture thereof; the source
of the first oxidizing
agent may comprise a diffuser and/or manifold in the tank; the source of the
second oxidizing
agent may comprise a generator that generates hydroxyl radicals; the apparatus
may further
comprise an ultrasonic transducer, a UV light source, or both an ultrasonic
transducer and a UV
light source in the tank; and the apparatus may further comprise an air
injector adapted to inject
air into the water of the tank and controlled by the controller.
[0007] According to an aspect, there is provided a method of
extracting natural fibres from
fibre feedstock that comprises gum adhered to the natural fibres, the method
comprising
introducing the fibre feedstock into water, in a first stage, injecting an
oxidizing agent into the
water and permitting the oxidizing agent to react with the gum, the oxidizing
agent inducing an
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
3
oxidation reduction potential (ORP) in the water, and wherein a sufficient
amount of oxidizing
agent is introduced to achieve a first ORP level and, in a second stage,
controlling the amount of
oxidizing agent introduced into the water to reduce the ORP and maintaining
the ORP within a
predetermined range that is less than the first ORP level and permitting the
oxidizing agent to
continue reacting with the gum, and removing released fibres from the water.
[0008] According to other aspects, the method may comprise one or
more of the following
features, alone or in combination: the first ORP level may be at least 500 mV;
the method may
further comprise the step of filtering the water to remove released gum after
the first ORP level
has been achieved; the predetermined range may be between 150 mV and 300 mV;
the gum may
comprise proteins, and in the first stage, the oxidizing agent denatures at
least a portion of the
proteins on exterior surfaces of the fibre feedstock; a second oxidizing agent
may be injected into
the water during or after the second stage; and the water may be agitated
during the first stage and
the second stage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] These and other features will become more apparent from the
following description in
which reference is made to the appended drawings, the drawings are for the
purpose of illustration
only and are not intended to be in any way limiting, wherein:
FIG. 1 is a block diagram of a process for degumming natural fibres.
FIG. 2 is a block diagram of a process for drying natural fibres.
FIG. 3 is a perspective view of a treatment chamber.
FIG. 4 is a perspective view of a fibre cage being introduced into a treatment
chamber.
FIG. 5 is a perspective view of a fibre cage received within a treatment
chamber.
FIG. 6 is a perspective view of a fibre cage being rotated in a treatment
chamber.
FIG. 7 is a perspective view of alternatives of a fibre cage and treatment
chamber.
FIG. 8 is a top plan view of alternatives of a fibre cage and treatment
chamber.
FIG. 9 is a perspective view of an open fibre cage.
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
4
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0010] An apparatus and method for extracting natural fibres from
fibre feedstock that
comprises gum between the natural fibres will now be described with reference
to FIG. 1 through
9.
[0011] The method described herein relates to the extraction of natural
fibres by removing or
breaking down the natural glue-like compounds that bind the fibres together.
The glue-like
compounds may include cellulose, hemicellulose, proteins, lignin, sacchari
des, pectins, wax,
hydrotropes, and other biological compounds as well as some other trace
elements_ These
compounds, which may vary between different sources of fibre, will be referred
to collectively as
"gum", and the release of the natural fibres from the gum will be referred to
as "degumming".
Suitable feedstocks for the process described herein may include hemp, flax,
ramie, or other similar
sources of natural fibres that must be degummed to obtain useful fibres. The
fibre feedstock used
in the process below may be subjected to pre-processing steps that may involve
mechanically or
biologically breaking down and/or separating portions of the vegetation, such
as decortication or
retting, to separate some or all of the tough, woody portion of a hemp plant
from the soft exterior
to facilitate treatment of the portion of the vegetation from which the
natural fibres will be
extracted. Another pre-processing step may include a wash cycle, which may
involve injecting
water, agitating, and removing the water, to remove easily separable material
from the fibres and
reduce the amount of material to be treated during the process discussed
below. These pre-
processing steps will not be described further. In the discussion below, it
will be assumed that the
fibre feedstock comprises decorticated, raw fibre or an equivalent. This may
vary depending on
the pre-processing steps employed, and the treatment process described herein
may be modified
to account for the feedstock to be treated.
[0012] The method may start by introducing fibre feedstock into
water and, while agitating
the fibre feedstock in the water, introducing a first oxidizing agent into the
water. The first
oxidizing agent is caused to react partially to the gum. A second oxidizing
agent is selectively
introduced into the water to react with the partially reacted gum to release
the fibres from the fibre
feedstock_ The released fibres are removed from the water_
[0013] In one example, the method may use a first oxidizing agent
and a second oxidizing
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
agent that is more reactive than the first oxidizing agent. The first
oxidizing agent may be easier
and/or less expensive to produce, or more readily available in large
quantities, and may be used to
complete a portion of the reaction used to extract the natural fibres. The
second oxidizing agent,
which is more reactive than the first oxidizing agent, may be used to complete
the reactions
5 necessary to extract the natural fibres. It will be understood that the
endpoint of the reaction will
depend on the quality of fibre that is to be extracted and the type of fibre
feedstock that is being
treated, and that in some examples, more or less of a second oxidizing agent
may be used to extract
a particular grade of fibre_ By using separate oxidizing agents, a less
expensive oxidizing agent
may be used to break down the less stable components of the gum, and a second,
more reactive
oxidizing agent may be used to compete the extraction by breaking down more
stable components
of the gum. Care may be taken in the type and concentration of oxidizing
agents as well as the
reaction time to avoid unnecessary or excessive damage.
[0014] The first oxidizing agent may be oxygen (02), ozone (03),
or a mixture of both. In one
example, commercially available equipment may produce a stream of 85% oxygen,
10% ozone,
and 5% other gases. The second oxidizing agent may be hydroxyl radicals (OH),
which are more
reactive than oxygen or ozone, but also more difficult to produce and use.
This second oxidizing
agent may be used to further break down the remaining gum and/or oxidation
products remaining
after the reaction with the first oxidizing agent.
[0015] Referring to FIG. 1, an apparatus 10 is depicted that may
be used to separate fibres,
such as hemp fibres. Apparatus 10 has a tank 11 that contains water and is
capable of receiving
fibre feedstock. Tank 11 may have an agitator 12 for agitating the fibre
feedstock in the water. A
source of oxidizing agent 106 and/or 108 is configured to introduce a first
oxidizing agent into the
water via an injector 110 connected to a manifold and/or diffuser 112 or other
injection apparatus
that is designed to distribute the oxidizing agent throughout the tank.
[0016] Referring to FIG. 2, there will now be described the components of
an example system,
which includes three basic sub systems: a plumbing system, an electrical
system, and a gas system.
[0017] In the plumbing system the water may start in reservoir
102, pass through a pre-screen
assembly 138, recirculation filters 116, additional treatment filters 120 and
diffusers 112 before
being used in tank 11, and returned to reservoir 102.
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
6
[0018] The plumbing system may also include pump 104, venturi (not
shown), and UV
sterilizer 114.
[0019] The electrical system may be centered around a centralized
control panel that houses
the electrical components, switches, and indicators, such as: power supply,
disconnect/lockout,
control panel, circuit breakers, door switches, float switches, relays, and
contactors. A source of
electricity 140 provides power to components that needs it through electrical
connections 142.
[0020] The pump control may include various controllers and
sensors other than those
depicted, such as a door switch, a float switch, a pump relay, a pump
contactor, a pump switch,
and signal to oxygen and ozone relay.
[0021] The gas system may collect air from an ambient air source 160 to
supply 02 source
106 and 03 source 108, which may be introduced into the water through gas
diffusers 112.
[0022] The gas control may include oxygen control components, such
as signal receiver from
pump contactor, 02 door switch, oxygen relay/contactor, and an 02 generator.
The gas controller
may include ozone control components, such as a signal receiver from pump
contactor, 03 door
switch, ORP analyzer, 03relay/contactor, 03 pressure switch, 03 solenoid, and
plasma board.
[0023] The UV control, ultrasonic control and fan may each include
an on/off signal from
PLC, a door switch, and/or an on/off switch, as required.
[0024] Also shown in FIG. 2 is the flow of hemp fibres. A supply
of fibres 144 is supplied to
one or more tanks 11 for treatment. After treatment the degummed fibres may be
transferred to a
roller press 146 to remove excess water, which may be transferred back to
reservoir 102. The fibres
may be further dried in a fibre dryer 148, and further processed in fibre
openers 150 and a step
cleaner 152 to produce cottonized hemp fibres 154.
[0025] Referring again to FIG. 1, the fibre feedstock may be
agitated within the water to
increase the contact with oxidizing agent and to encourage mechanical
separation of the gum and
the fibres to be extracted. The fibre feedstock may be agitated by rotating a
container as discussed
below. The fibre feedstock may also be agitated by generating turbulence in
the water, such as by
using water pumps or a mechanical agitator. The fibre feedstock may also be
placed in a pressurize
vessel and subjected to a high pressure flow of fluid to increase the contact
of the oxidizing agent
with the gum in the fibres.
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
7
[0026] Once the reaction has progressed to a certain point, an
additional oxidizing agent may
be introduced in a more selective manner to target the remaining gum, such as
components that
may take longer to react, or are unable to be reacted by the first oxidizing
agent, but may react
further with an additional, more aggressive oxidizing agent. The additional
oxidizing agent may
be hydroxyl radicals. The second oxidizing agent may be introduced in various
ways. If the second
oxidizing agent is hydroxy radicals, given their instability, the hydroxyl
radicals may be generated
in situ, such as through photolysis of precursors such as hydrogen peroxide
132 that is introduced
into tank 11 and/or ozone_ A catalyst, such as titanium dioxide, may also be
used to produce
hydroxyl radicals. The further oxidizing agent may be generated in situ using
UV lights 34 (shown
in FIG. 3) in tank 11. The manner in which the further oxidizing agent is
introduced may vary
depending on the type of oxidizing agent.
[0027] Apparatus 10 may have a controller 20 that controls the
introduction of the agent(s)
and the related equipment described herein. Controller 20 may have an
interface such as a touch
interface 122 that display indicators and may include manual controls.
Controller may controlled
manually, may have instructions to automatically control the equipment based
on readings, or may
have a combination of manual and automated controls.
[0028] The fibre feedstock may be treated by controlling the
concentrations of one or more
oxidizing agents in the reaction vessel to control the reaction kinetics
within tank 11 at different
stages of the treatment process, and to promote the reaction of the oxidizing
agent with the gum
while minimizing reactions with the fibre. In addition to breaking down the
gum, the oxidizing
agents may also be used to bleach the hemp fibres by allowing the oxidising
agents, such as ozone
and peroxide, to continue reacting with the organic material in the hemp
fibres, and in particular,
the colouring agents in the hemp fibres.
[0029] An example of a process to extract hemp fibre will now be
described. The example
may be adapted to extract other types of fibres, and may be modified to
include different oxidizing
agent, different equipment, etc. to achieve the desired results. To start, pre-
processed hemp fibre
feedstock may be placed into a container 22, which is water impermeable, for
treatment where
ozonated/UV irradiated water is passed through container 22 and fibres_ The
feedstock and/or
water may be agitated to encourage thorough mixing and even treatment. Natural
glues are
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
8
oxidized into water soluble organic compounds that may be removed from the
fibres by the
flowing or agitated water. The soluble organic compounds may undergo further
redox reactions
while in solution with oxidizing agents, or may be filtered out in some cases
using recirculating
filters 116 and/or water filters 120. At certain points in the cycle the
system may manipulate the
conditions for Advanced Oxidation reactions to take place between pre-
determined set points.
0 .R .P. (Oxidation Reduction potential) readings may be taken using 0 .R .P
probe 128 and analyzer
126 and may be used, along with other measurements, to determine treatment
cycle end point or
transitions between treatment stages_ Referring to FIG_ 2, after water is
passed through the tank(s)
11, it may be filtered by a pre-screen assembly 138 to remove large debris
that may damage the
recirculation pump 135 and passed through recirculating filters 116 and/or
water filters 120. The
flow of water may be controlled by a three-way valve 134, shown in FIG. 1.
Filtrate may be
returned along path 118 to the treatment water reservoir 102 and fed back into
tank 11 by a main
pump 104. This water may be recycled until it evaporates, is absorbed into the
natural fibres or is
used in treatment reactions. A water level sensor 124 may be used to indicate
when makeup water
is required in reservoir 102.
[0030] The fibre may be considered a media in a closed water
treatment loop. The
contaminants are removed as they are drawn into solution from the natural
fibres being treated.
This may be implemented as a batch process that may take, for example, 2-6 hrs
depending on
variables. Periodically more intensive water treatment cycles may be run to
remove specific
contaminants with all the same equipment. In some cases, it may be more
efficient to use a
continuous process rather than a batch process. In a continuous process, the
equipment may be
modified to move the hemp fibres between treatment steps in different tanks 11
through the
process, similar to a wool scour system. The components will be similar to
those discussed above,
but separated into separate tanks 11 or steps.
[0031] Through appropriate design, it may be possible to create an
environment inside the
process where oxidation conditions are capable of removing the unwanted
organic compounds to
achieve "degumming" of natural fibres. This process may use components that
are designed for
use in the water treatment industry, which is beneficial as the equipment is
designed for large scale
continuous operation and long service life at a reduced cost relative to
custom-designed equipment.
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
9
[0032] O.R.P. probe and analyzer
[0033] Oxidation Reduction Potential (0.R.P.), typically measured
in millivolts, may be used
as a tool to control the oxidation process. Ozone reactions typically occur in
a predictable pattern
that correlates to O.R.P. readings. These measurements may be used in a few
ways. First it may
indicate when certain groups of reactions are occurring. This ability to
control which type of
reactions are most likely to occur may be used to improve or optimize the
process and the quality
of the output fibre_ When the process starts, the O_R_P_ may be between, for
example, 175-225mV
The first batch of reactions may occur around 240mV. The system may reach this
O.R.P. level and
stay there until those reactions are complete. Selection of the oxidizers and
the manner in which
they interact with the fibre being treated affect the amount of oxidizers
required, the output fibre
characteristics, and the treatment cycle time. Introduction of more reactive
oxidizers in a controlled
manner drastically reduces the time required for treatment. Then O.R.P. will
typically jump to the
next level where a new set of reactions take place and maintain constant until
those reactions are
complete, then the O.R.P. will again increase. This process continues until a
target O.R.P. is
reached and maintained for a set time period, after which the full treatment
cycle may be
considered to be completed. When the data is charted on a line graph it will
typically show a step-
like structure where the flat areas indicate O.R.P. levels where certain
groups of reactions take
place. Each of the steps are optimized to breakdown targeted organic compounds
or products of
the reactions in the preceding steps.
[0034] Another function of an O.R.P. probe and analyzer is to
cycle on and off the gas
equipment to prevent wastage and improve efficiency. When a certain O.R.P.
range is entered into
controller 20, which may be a programmable logic controller (P.L.C.) that is
used as controller 20
of the process as a whole, it may be used to control the gas equipment to
reduce energy
consumption by only generating the minimum required amount of treatment gasses
required for
treatment.
[0035] In some examples, the O.R.P. may be controlled at different
levels for different
treatment stages_ For example, in an initial stage, an oxidizing agent, such
as ozone, may be
injected into the slurry of water and feedstock until a relatively high O.R.P.
is reached relative to
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
the other treatment stages, such as around 500-700 mV. This level of O.R.P.
may be achieved by
injecting a relatively high concentrations of the oxidizing agent. During this
stage, the oxidizing
agent will react with the gum that is easily-accessible on the hemp fibres,
such as gum that is on
the outer surface, and allow it to be separated from the fibres. It has been
found that this initial
5 "Shock" step may be useful in denaturing proteins that are part of the
gum and carried by the hemp
fibres, allowing them to be separated from the hemp fibres. The denatured
proteins may then be
either filtered out, such as in recirculating filters 116, or decomposed by
allowing the oxidation
reaction to continue_ This may be particularly useful when targeting gum or
proteins on the outer
surface. In a subsequent stage, the amount of oxidizing agent being injected
may be reduced or
10 temporarily stopped, allowing the reaction to slow. It has been found
that the oxidizing agent reacts
with both the hemp fibres and the gum, but that it reacts more readily with
the gum. As the gum is
found between fibres, slowing the reaction (as indicated by a reduced O.R.P.,
such as to the levels
indicated above) allows the oxidizing agent to react with the less-accessible
gum targeted while
reducing damage to the hemp fibres.
[0036] The reaction may end when a desired quality of hemp fibre is
achieved. Depending on
the intended use or further processing steps, the acceptable amount of gum may
vary. In some
cases, it may be desirable to remove substantially all of the gum and/or to
bleach the hemp fibres.
This may be achieved by varying the treatment time and the strength and
concentration of the
oxidizing agent(s) used. In some cases, an additional, stronger oxidizing
agent may be added as
discussed above to provide additional control over the reaction.
[0037] Reaction Stages
[0038] During the degumming process, the fibres may be degummed in
different ways. In one
method, ozone may be added to a point where the fibre feedstock is subjected
to hydrotrope
oxidation and protein denaturing reactions. Once these steps are complete, the
ORP will rise to
approximately 600-650 mV at which point the supply of ozone may be shut off
and the denatured
protein and other components may be filtered off in a wash/filtration process.
After the
wash/filtration process is complete, the ozone may be reintroduced to maintain
an ORP of
approximately 600-650 mV to complete the reaction with gum that is between
fibres and/or to
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
11
bleach the fibres. When the reactions are complete, the ozone reactions may
increase to
approximately 700mV, indicating that the degumming reactions are complete. In
some cases
where more gum is permitted in the final product, a different ORM may indicate
that the reaction
is complete.
[0039] In some cases, the gum content on the fiber may be naturally low,
meaning there is less
gum to be removed to meet set specifications. In these cases the gum content
between fibers is
significantly less. A similar process may be used as described above, however
once the
wash/filtration process is complete the ozone will be reintroduced to maintain
an ORP of
approximately 300-500 mV to ensure full reaction with gum in between fibres is
complete, without
bleaching the fibres. When the reactions are complete the ozone reactions will
increase to
approximately 600mV and the degumming reactions may be considered complete. In
this example,
the ORP remains high enough without additional ozone added.
[0040] The treatment may proceed in batches, which each stage
being performed in the same
tank, or it may be a progressive system, where the feedstock is transferred
between different tanks.
For example, a first tank may have a high concentration of an oxidizing agent,
and the feedstock
may be transferred to another tank once the reaction has reached a desired
endpoint. For example,
once the ORP has reached a desired level, indicating a suitable amount of
protein has been
denatured, the fibre feedstock may be transferred to a wash tank to separate
the protein. The fibre
feedstock may then be transferred to subsequent tank with a lower
concentration of an oxidizing
agent to target the less accessible gum carried by the fibres. Rather than
perform each task in a
single tank, a series of wash, rinse, and reaction vessels may be used with
the same or different
reactants and different equipment to allow the treatment to proceed as
desired, which may include
a bleaching tank. Transferring between tanks may be facilitated by placing the
fibre feedstock in a
porous container as discussed above.
[0041] Gas Diffusion
[0042] In general, introducing smaller gas bubbles will improve
the overall efficiency of the
reactions that occur in solution. When small gas bubbles are in solution, they
have an extremely
large surface area available for oxidation reactions compared to larger
bubbles. When gas bubbles
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
12
are small enough, they are not affected by buoyancy and become suspended in
solution for
extended periods of time. These bubbles then become susceptible to
electromagnetic forces
allowing reactions targeting covalent bonds to be preferred. This prevents the
waste of valuable
treatment gases that otherwise would rise to the surface and escape out the
vent and require
removal from the exhaust gas stream. Micro bubbles of the same gas repel each
other due to having
the same electrical charge this acts to further diffuse the gasses within the
treatment water. The
equipment may be designed to improve gas diffusion at low pressure.
[0043] In one example, referring to FIG 3, a mixture of water and
gas may be passed through
a diffused gas manifold 40 diffusers to create microscopic gas bubbles, while
compressed air may
be introduced through manifolds 38. The process of creating and maintaining
very small stable
bubbles is a result of complete system design. Maintaining a laminar flow,
appropriate flow rate,
temperature and pressure throughout the process may be used to improve
efficiency. The solubility
of oxygen and ozone are affected by temperature and pressure. Cold water is
able to hold more
dissolved gas than water at higher temperature. Oxidation reactions are
exothermic, and the
recirculation pump is cooled by the process water therefore a chiller may be
used to maintain a
desired temperature range during operation. While it is possible to dissolve
higher concentrations
of gas at higher pressure, it also requires more energy to generate pressure.
Operating at low
pressure (less than 15psi/1.03bar) may allow for energy savings in the
process. Sudden pressure
drops may cause gas bubbles to expand and come out of solution. As such, care
should be taken
to prevent this from occurring within the system.
[0044] The pH of the water may also be controlled to adjust the
reaction within the vessel. For
example, a higher pH may be used to increase the speed of the ozone reactions.
If the pH is raised
through the addition of caustic, the caustic may also help scour gum, such as
proteins, from the
hemp fibres. In one example, a pH of around 10 was found to be beneficial. As
with the O.R.P.
discussed above, the pH may vary between treatment stages between a more
aggressive reaction
and a less aggressive reaction.
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
13
[0045] Treatment gas
[0046] In one example, the main treatment gases may be ambient
air, oxygen and ozone. Both
concentrated gases may be generated onsite with the consumables being ambient
air and
electricity.
[0047] Oxygen (02) may be taken from the atmosphere (about 21%) and
concentrated to
around 85-90% or more. This may be done via a pressure swing adsorption system
called an
oxygen concentrator. Referring to FIG. 2, ambient air 160 may be compressed
and passed through
vessels 106 that may contain a specific adsorbent media which retain nitrogen
in a particular
pressure range to increase the concentration of 02. In the discharging vessel,
the media may retain
nitrogen high pressure allowing oxygen to leave the vessel first. The product
oxygen may be fed
to the outlet for use while a portion is used to purge nitrogen from the other
vessel. There may be
more than one vessels 106 that are fed with an air compressor and that cycle
back and forth via an
array of solenoid valves and the machine is fed with an air compressor.
[0048] Ozone (03) may also be generated onsite by flowing oxygen
gas through an ozone
generator 108 based on oxygen from vessel 106. In one commercially available
ozone generator,
electrical arcs are discharged to split 02 molecules into individual oxygen
atoms. A portion of
these oxygen atoms combine with other oxygen molecules to create ozone. Ozone
is very reactive
relative to oxygen and has a relatively short half-life. Even in the absence
of all other substances,
ozone will typically degrade back to molecular oxygen (02) in a relatively
short time. As such,
ozone is typically generated at the point of use.
[0049] Carbon dioxide (CO2) may be added to lower the pH of the
process water, if necessary,
to enhance treatment and assist in precipitating dissolved metals in the water
treatment cycle.
[0050] Advanced Oxidation Process Equipment
[0051] The phrase "Advanced Oxidation Process" (AOP) may refer to the
creation of
extremely reactive species of particles called free radicals. Free radicals
typically have a life span
of seconds so they must be created at or extremely close to the point of
treatment. There are
multiple separate mechanisms in the process that can create the specific
particles required for the
Advanced Oxidation Process to occur, examples of which are discussed below.
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
14
[0052] UV systems 32 and 34 in tank 11 may operate at different
wavelengths of ultraviolet
light. Referring to FIG. 3-6, UV system 32 within tank 11 may be used to form
atomic oxygen and
the hydroxyl radical for advanced oxidation within the water. Atomic oxygen
may be produced
when UV energy breaks a bond in the Ozone molecule (03+UV 02+0). The hydroxyl
radical
may be formed during UV light dissociation of H202 by a different wavelengths
produced by a
second set of UV lights 34, which may be different UV lights in tank 11. When
present, the 11202
injection system may introduce hydrogen peroxide (H202) and initiate the
associated reactions.
The reaction of WO/ + 03 is called the peroxone process_
[0053] There are several reactions in AOP that may be promoted,
resulting in free radical
particles being present inside the fibre treatment chamber when the AOP
systems are operated. A
full explanation of the reactions and products of those reactions goes beyond
the scope of the
present discussion, except to state that oxidation reactions typically happen
in a particular sequence
that is not random and that may be measured and monitored. Ozone prefers
particular reactions
over others and with proper control compounds may be predictably reacted out
in a sequence that
may correlate to a particular O.R.P. level in the water. While the series of
reactions of ozone may
happen in a relatively linear predictable pattern, the AOP may be less
predictable. This may be due
to the tendency for free radical particles to react with the closest possible
compound or molecule
rather than "searching" for a preferred reaction. This makes the introduction
of these free radical
particles an important consideration. Used at the right time in the degumming
process, AOP may
assist ozone and oxygen in the oxidation of organic compounds. Care must also
be taken to avoid
damaging the natural fibres being treated by AOP reactions. Timing, dosage,
and duration may be
variables controlled by a controller in the operation of the AOP systems
discussed herein.
[0054] Another function of the AOP systems besides reducing the
treatment time may be to
provide treatment to the process water and react with or precipitate compounds
that ozone cannot
or is less likely to remove alone. Natural fibre typically contain traces
amounts of elements and
compounds that do not readily react with ozone. These compounds are present in
relatively small
concentrations but may build up as the water is reclaimed and reused. A
combination of oxidizers
may be used to precipitate molecules or elements that may be resistant to
oxidation reac ti on s _ Once
precipitated, they may be removed from the water with appropriate filtration.
This may be
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
performed continuously, or periodically when required.
[0055] UV Systems
[0056] There may be one or more separate UV systems. In addition
to UV lights 32 and 34
5 depicted in FIG. 3, another UV system, represented by UV system 114 in
FIG. 1, may be used as
a standard UV sterilization of process water to eliminate
microbes/bacteria/fungi that may have a
higher tolerance of oxidants in process water as it is introduced into tank
11. In this system small
amounts of free radical particles are also created_ It will be understood that
other systems may not
include UV light if the second oxidizing agent is introduced in other ways,
and if sterilization is
10 determined to be unnecessary, or achieved in a different manner.
[0057] Hydrogen peroxide injector
[0058] In some examples, hydrogen peroxide may be introduced in
relatively small amounts
and at pre-determined points in the process, such as via a venturi and a
dosing pump, represented
15 by H202 injection block 132 shown in FIG. 1. The introduction of a small
amount of hydrogen
peroxide may shorten cycle times and when combined with sufficient dissolved
ozone, the
peroxone process may be utilized for targeting specific compounds.
[0059] Ultrasonic transducers
[0060] Referring to FIG. 3-6, ultrasonic transducers 36 may be used
periodically in the
treatment cycle to assist in the dissolving of organic compounds from the
fibres. Transducers 36
may be used to separate fibres from gum using induced vibrations or by causing
microbubbles in
solution to cavitate on the gum and/or fibres. Transducers 36 may also be used
to encourage fibres
greater ozone contact as the fibres vibrate open, and to mechanically scour
the gum from the fibres.
[0061] Design of System Plumbing and Vessels
[0062] In designing the various components, care should be taken
to select materials that are
resistant to the oxidizing agents and other equipment used herein Suitable
materials may include
P.V.C., Polyethylene, and Stainless Steel.
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
16
[0063] Treatment water reservoir
[0064] Referring to FIG. 1, the treatment water reservoir 102 may
be a polyethylene water
tank to hold treatment process water. The return line 118 and freshwater fill
line (not shown) may
run to the bottom of the tank using dip tubes so that water returning from the
treatment chamber(s)
is saturated with gas such that introducing it to the bottom of the tank may
improve efficiency by
using the excess gas from fibre treatment to be used for water treatment.
Allowing returning water
to drop from the top of the tank onto water already in the tank may cause the
gases to come out of
solution and exit out the vent of the tank. This may be done during the
degassing cycle in concert
with coarse bubble air manifolds. During the fibre treatment cycle, gas
injected at the bottom rises
through the water column where it is available to react with contaminants in
the treatment water
and the fibre present inside the chamber. The use of dip tubes may prevent
particles or debris that
may be in the reservoir from settling on the bottom. The vent from this tank
may runs through an
ozone destruct unit (not shown) before being discharged.
[0065] Referring to FIG. 2, process water tank 102 may also receive waters
from a roller press
146, treatment cambers 11, and filters 120.
[0066] Fibre Treatment chamber
[0067] Referring to FIG. 4 ¨ 8, fibre may be placed into
containers 22, such as purpose built
cylindrical stainless-steel cages as shown, where the fibre is intended to
remain for the wet portion
of the process. Referring to FIG. 9, an example of a container 22 is shown
with a mesh or perforated
outer surface, and an end plate 26 that may be opened to provide access to the
interior. The cage
may double as agitator 12, and may have baffles 24 to help agitate water and
fibre as the cage
rotates. The degumming process takes place within the individual treatment
containers 22. There
may be multiple processes/reactions happening simultaneously within containers
22 that act in
concert to perform the degumming of natural fibre. In some examples, the
reactions may occur in
separate containers 22 as the fibres progress through different containers 22.
Container 22 that
contains the fibre may be slowly rotated to promote thorough mixing and
prevent short circuiting
which results in uneven treatment within the containers 22. Other designs that
promote treatment
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
17
of the fibres may include other methods of agitating the fibres in the water,
such as through the use
of mixers or fluid pumps, or through the use of pressurized or high flow rates
through pressure
vessels that direct the flow through the fibres (not shown). Apparatus 10 may
be designed to direct
the oxidizing gasses in solution evenly across the bottom of tank 11 below the
rotating container
22. Lights of first UV system 32 and second UV system 34 may be mounted inside
tank 11 as
discussed above to introduce the second oxidizing agent at specific points
within the treatment
cycle. This may be accomplished by limiting the introduction to a certain
volume of the chamber,
or limited in time, or combinations thereof
[0068] Walls of tank 11 and the mechanisms inside it may be
constructed from stainless steel.
In FIG. 3-8, the walls of tank 11 are either not shown or are shown as
transparent. The design may
be based on a cellular concept where individual tanks 11 may be set up in
series or parallel to
achieve whatever capacity is desired. The system may be designed to have the
AOP reactions
contained within tank 11. Inlets and outlets (not shown) may be placed to
encourage even
distribution of treatment gas throughout the tank 11. Inlets may be routed
into the bottom of tank
11 where water containing the treatment gas flows upwards through the tank 11
and container 22
and water may be drawn off the near the surface and returned to the treatment
water reservoir.
[0069] Natural fibre may be loaded into containers 22 and lowered
onto mounts 28 inside the
tank 11. Containers 22 may be slowly rotated to stir the fibre during
treatment, for example, at
approximately lORPM, and helps to prevent short circuit flow paths within the
fibre. Promoting
even treatment of all fibres helps produce predictable, consistent results
when degumming natural
fibres as product consistency often improves the value to purchasers of the
separated fibres. An
ultrasonic transducer 36 may also assist in preventing pockets of lower
treatment.
[0070] Tank 11 may have one or more compressed air manifolds 38
for introducing
compressed air, such as for a degassing cycle described below. A diffused gas
manifold 40 may
also be included for introducing the first oxidizing agent.
[0071] To increase the number of AOP reactions, the design may
include UV sterilizers placed
at points in the system so that free radicals created are present in the
treatment chamber and in
contact the fibre being treated_ As these particles react relatively fast, UV
lights may be mounted
directly in tank 11 and inline where needed.
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
18
[0072] Water Treatment Cycle
[0073] It was found that, after miming the process for a number of
cycles, heavy metals
dissolved from the natural fibre were found to have accumulated in the
treatment water. Metals
may be removed by precipitation and filtration. Using the system to increase
the ORP may
precipitate certain metals so they can be filtered out of the treatment water.
Reaching ORP levels
that allow metals to precipitate may require extremely efficient diffusion and
high purity ozone.
During a treatment cycle, a bypass may be opened to a bank of assorted filters
that removes
suspended particles and precipitated metals. Running the system in the water -
treatment cycle may
only be done once the treatment water requires. If it is deemed beneficial,
H202 may be injected
to assist with the water treatment cycle. Running at high ORP levels for
extended periods may be
hard on components of the system. Being a closed loop recirculation system
once the desired ORP
level is reached, the filtration step may take a relatively short amount of
time after which the system
may be returned to the regular treatment cycle settings.
[0074] Degassing Cycle(s)
[0075] Once certain stages of treatment have been accomplished, a
degassing cycle may be
initiated to remove residual oxidizers pri or to the next treatment step, for
example, after completing
a treatment cycle and prior to opening the treatment chamber. During this
cycle, gas generating
equipment may be shut down and a solenoid valve to compressed air manifolds 38
may be opened
along the bottom of tank 11. Coarse air bubblers may be used to remove the
dissolved gasses from
the water inside tank 11. Depending on the design, compressed air may be
injected using the same
manifold used for ozone and oxygen.
[0076] Referring to FIG. 1, there is shown a schematic of an
example of a process flow for
recycling the water used in the method and apparatus 10 which may include any
of the components
discussed above. Water may be drawn from a water reservoir 102 and sent by a
pump 104 to tank
11. 02 and 03 sources 106 and 108 may inject gas into the water sent by pump
104 through a gas
injector 110 and micro-bubble diffusers 112_ The water may be treated with IN
light 114 prior to
entering tank 11. After being used in tank 11, the water may pass through
recirculation filters 116
CA 03215064 2023- 10- 10
WO 2022/213215
PCT/CA2022/050551
19
before being returned to water reservoir 102 along return path 118. If the
water requires further
filtering, it may instead be passed to water filters 120. Controller 20 may
have a user interface 122
and may receive inputs from a water level sensor 124 in reservoir 102, an ORP
analyser 126 that
receives measurements from an ORP probe 128, and pressure sensors 130 in the
additional filters
120. Controller 20 may also be configured to communicate with remote equipment
using a
SCADA remote monitoring unit 125. Controller 20 may have control outputs to
pump 104, 02
source 106, 03 source 108, a hydrogen peroxide injector 132, tank 11, UV light
114, and a three
way valve 134_ Water from reservoir 102 may be circulated through a chiller
136 to control a
temperature of the water.
[0077]
In this patent document, the word "comprising" is used in its non-
limiting sense to
mean that items following the word are included, but items not specifically
mentioned are not
excluded. A reference to an element by the indefinite article "a" does not
exclude the possibility
that more than one of the elements is present, unless the context clearly
requires that there be one
and only one of the elements.
[0078]
The scope of the following claims should not be limited by the
preferred embodiments
set forth in the examples above and in the drawings but should be given the
broadest interpretation
consistent with the description as a whole.
CA 03215064 2023- 10- 10
