Note: Descriptions are shown in the official language in which they were submitted.
METHOD AND SYSTEM FOR PELLETIZING SPENT BLEACHING EARTH
FIELD
[0001] This invention is in the field of processing spent bleaching earth
(SBE), and more
specifically to pelletizing spent bleaching earth.
BACKGROUND
100021 Bleaching products, commonly called bleaching earth or bleaching clay,
are typically
comprised of naturally occurring mined products that are manipulated by
processes including acid
activation and heat treatment to enhance the filtration effectiveness of these
products. Refining is
an important step in the production of edible oils. Bleaching of the crude
vegetable oil is a vital
part of that process in order to decolorize the vegetable oil and remove
contaminants detrimental
to the appearance and longevity of the final product, Bleaching adsorption
using clay, zeolite, and
diatomaceous earth substrates is the most common and cost-effective method to
attain high volume
production.
[0003] SBE is considered a hazardous industrial waste and is commonly disposed
in landfill
without pre-treatment. The decomposition of SBE in the environment is
inhibited by the high oil
content and is very slow. Storage of SBE is inadvisable due to ecological
reasons as these
pollutants may penetrate into the ground water and infiltrate water-bearing
horizons. Moreover,
their open-air storage may cause spontaneous combustion. Previous efforts to
economically
regenerate the SBE have resulted in landfill disposal and/or incineration.
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[0004] US Patent No. 4,285,832 filed August 11, 1980 by George 0. Orth, Jr.
describes a method
for extracting residual vegetable oil contained in spent bleaching clays used
in refining and
processing of such oil and for processing the extracted clay for reuse. The
spent bleaching clay
containing the residual vegetable oil is mixed with water, an organic binder
and a plastic clay to
form a composition of putty-like consistency which can be formed into
particulate solids of
suitable size for solvent extraction of the oil. The vegetable oil in the
particulate solids is then
extracted by solvent extraction with a suitable solvent. The remaining
particulate solids with the
oil removed may be retorted to produce an activated carbon/clay product useful
to lighten the color
of the oil being processed, as a filter aid, for water treatment purposes or
for other uses where
activated carbon is generally used.
SUMMARY
[0005] Any and all aspects as described herein, individually or in any
combination consistent to
one of skill in the art.
100061 The present disclosure includes a process for pelletizing a spent
bleach earth (SBE) into a
clay-biocarbon composite including classifying the SBE based on at least one
parameter of the
SBE, selecting at least one filler compound and mixing at least one filler
compound with the SBE
to make a mixture, forming a plurality of pellets out of the mixture, and
pyrolyzing the pellets to
produce the clay-biocarbon composite.
[0007] In one aspect the process for pyrolyzing a pelleted spent bleach earth
(SBE) includes
advancing the pelleted SBE with a distributer to a first thermal chamber for
providing even thermal
processing, releasing the pelleted SBE to a second auger to cool to room
temperature, and
condensing at least one volatile compound emitted from the pelleted SBE during
thermal
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processing to produce a condensate for reuse. The process may further include
producing and
storing a pyrolysis oil from the condensate. In another aspect, the process
may include removing
water and oxygen from the condensate to produce a drop-in liquid fuel.
[0008] In another aspect the process may include destroying any toxic
compounds, such as dioxins
.. and furans, in the syngas in a secondary chamber within the first thermal
chamber.
[0009] The process may further include advancing the pellets with a
distributer to a first thermal
chamber for providing even thermal processing of the pellets.
100101 In one aspect, the pellets may have granular shape.
100111 In another aspect, the filler compound may be selected from, but not
limited to, lime,
bentonite, citric acid, fine biocarbon, softwood, calcium, and iron.
[0012] In one aspect, the pellets may advance through the first thermal
chamber for approximately
20-minutes to 100-minutes. The temperature of the first thermal chamber may be
controlled to
about 400 C to about 900 C. Furthermore, the first thermal chamber may be
ventilated to allow
combustion of liquid and gaseous fuels to keep the first thermal chamber at
temperature.
[0013] In one aspect, the process may include emitting at least one volatile
compound from the
pellets and condensing at least one volatile compound into a condensate.
[0014] In another aspect, the process may include producing and storing a
pyrolysis oil from the
condensate.
100151 In one aspect the process may include removing water and oxygen from
the condensate to
produce a drop-in liquid fuel.
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[0016] The first thermal chamber may include a secondary chamber to destroy
any toxins in the
syngas. In another aspect the process may include heating the secondary
chamber to
approximately 11 00 C.
[0017] There is a significant value-proposition if the oil and the bleaching
earth can be recovered
and repurposed.
DESCRIPTION OF THE DRAWINGS
[0018] While the invention is claimed in the concluding portions hereof,
example embodiments
are provided in the accompanying detailed description which may be best
understood in
conjunction with the accompanying diagrams:
[0019] FIG. 1 is a flow chart illustrating a method of pelletizing SBE;
[0020] FIG. 2 is a process flow diagram of a pyrolysis plant for thermal
processing of the pelletized
SBE; and
[0021] FIG. 3 is a side perspective view of a cut-and-die tool for pelletizing
the SBE.
DETAILED DESCRIPTION
[0022] Throughout the following description specific details are set forth in
order to provide a
more thorough understanding to persons skilled in the art. However, well known
elements may
not have been shown or described in detail to avoid unnecessarily obscuring
the disclosure. The
following description is not intended to be exhaustive or to limit the
invention to the precise form
of any exemplary embodiment. Accordingly, the description and drawings are to
be regarded and
interpreted in an illustrative, rather than a restrictive, sense.
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[0023] Bleaching components may be used to decolorize the oil and may comprise
natural
bleaching earths for treating animal fats, acid-activated bleaching earths for
removing impurities,
activated carbon, for removing polyaromatic hydrocarbons and pollutants,
synthetic amorphous
silica compounds for removing phosphatides, metals and soaps, and sodium
metabisulphite for
decoloring the products that oxidize the impurities. Furthermore, dry
bleaching earth can also be
used such that the oil is heated before mixing with the bleaching earth and
then mixing a citric acid
solution, if desirable to bind trace metals and decompose any residual soap.
The oil is then mixed
with bleaching earth, for refining edible oils, hemp or cannabidoil and
biodiesel. These bleaching
components may be a common and cost-effective method to attain high volume
production of the
oils or biodiesel; however, this method also generates a substantial waste
stream of SBE. The
bleaching components may comprise clay, zeolite, and diatomaceous earth
substrates.
100241 In use, the bleaching components may be formed into a number of pellets
and stored in a
tank receiving edible oils to be refined. Alternatively or in addition to the
tank processing, the
pellets may be placed in a flow of the edible oils. Once the pellets have
become saturated, the
pellets may be transformed into SBE. The SBE may be a viscous mud-like
substance at this stage.
100251 The SBE may be considered a hazardous industrial waste and may be
commonly buried in
landfill without pre-treatment. The SBE may be susceptible to spontaneous
combustion;
consequently, handling and disposing of the SBE is a fire risk, an operating
expense, and a source
of environmental regulatory concerns. Therefore, proper management of SBE is
desirable, though
an unsolved economic and ecological problem. The SBE may comprise one or more
spent
bleaching components, oil, water, phospholipids, metals, organic compounds
sulfuric acid, sludge,
sulfonic acid, free fatty acids, and other like contaminants that are absorbed
and adsorbed during
the bleaching process which may be difficult to manage or dispose of due to
the diverse
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composition and/or high quantities of water-insoluble substances, e.g. fatty
acids, and macro and
micro contaminants.
100261 With reference to FIG. 1, the process 100 begins by receiving the
viscous SBE where the
viscous SBE may be received, tested, analyzed, and classified at step 110. At
this stage 110, the
viscous SBE may be sent for laboratory testing and analysis to test and
analyze the viscous SBE
for at least one of oil content, water content, and/or contaminant content.
Based on the testing and
analysis, one or more parameters of the process 100, 200 as described herein
may be adjusted. For
example, based on the content(s) of the viscous SBE, a ratio and/or type of a
filler compound may
be adjusted as an input to a mixing process 120. In this aspect, the mixing
process 120 may be
performed using a motor mixer to produce a mixed SBE. Alternatively, the
viscous SBE may be
classified as an acceptable SBE or an unacceptable SBE wherein the acceptable
SBE may be
processed using the process(es) as described herein and unacceptable SBE may
be rejected.
100271 The mixing process 120 may mix such that by a visual inspection the
filler compound is
completely mixed. The filler compounds may comprise one or more of a ferric
oxide, a lime, a
bentonite, a citric acid, a screened softwood (e.g. sawdust), a fine
biocarbon, calcium, another type
of acid, and/or any combination thereof. For example, ferric oxide may be used
to assist the
removal of hydrogen sulfide from biogas. Table 1 presents a few examples of
the filler compounds
that may be used for particular applications.
Table 1: Filler compounds and their use
Additive Use
lime (CAO) removes mercaptans
bentonite strengthens pellet
citric acid reductant for copper processing
fine hiocarbon odour adsorption
softwood increasing carbon content
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calcium odour adsorption
iron Removes hydrogen sulphide
[0028] The mixed SBE may be formed into one or more SBE pellets at step 130.
In this aspect, a
pellet mill, such as a pellet mill manufactured by California Pellet Mill or
the like, may be used.
Some details of the pellet mill 300 are provided with reference to FIG. 3. The
pellet mill 300 may
include a roller 310 comprising a die 320 and a cutter 330. The roller 310
forces the mixed SBE
out through the die 320 having a plurality of holes 340 with a with a
desirable diameter, e.g. 3/8-
inch, to shape the mixed SBE 302 into generally cylindrical clusters. Based on
the end-user
requirement, the cutter 330 may then rotate towards the clusters at a suitable
rotational speed to
produce a suitable length of SBE pellets 360. In other aspects, the cutter 330
may comprise an
oscillating or reciprocating blade to produce the suitable length of SBE
pellets 360.
[0029] The SBE pellets may be inspected at step 140 using a strength tester to
determine a friability
and if the SBE pellets are able to withstand thermal processing 200 without
complete degradation.
Suitability can be measured by crushing a sample pellet with a finger, or
using a pellet friability
tester. If one or more SBE pellets are unsuitable for the thermal process 200,
the unsuitable SBE
pellets may be returned to the mixing process 110. For example, the SBE
pellets may be unsuitable
for having an excessive oil content thereby have excessive viscous properties
reducing flowability.
In another example, the SBE pellets may be unsuitable for having a friability
below an acceptable
standard.
[0030] The suitable pellets, may have a cylindrical or a spherical shape, but
are not limited in
.. scope to these shapes. The suitable pellets may have characteristics that
enable high flow rates
with low channeling, have low-packing density, high surface activity, high
concentration, and are
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of a substantially carbonaceous structure such that the binding and shape of
the pellet remains.
Additionally, suitable pellets have granular properties to permit gas and/or
liquid to flow evenly
therethrough.
[0031] The suitable pellets may then be advanced for thermal processing 200 as
described in
further detail with reference to FIG. 2. A quantity of the suitable pellets
may be provided to an
infeed hopper 210 and then through an auger 220 that advances the suitable
pellets to a rotary
valve 230. In order to reduce shearing of the suitable pellets and permit an
even flow of the suitable
pellets into each rotary pocket (not shown) of the distributer 232 . The
distributer may comprise
one or more retorts 234 having an auger (not shown) within each retort 234. In
this aspect, the
three retorts 234 advance the suitable pellets through a thermal chamber 240.
The retorts 234 may
having tubular shape of 18-20 inch diameters and be temperature controlled. In
this aspect, the
retorts 234 may advance the suitable pellets such that the time taken for the
suitable pellets to pass
through the thermal chamber 240 may be about 20-minutes to about 100-minutes.
In other aspects,
one or more conveyors may be used.
[0032] The thermal chamber 240 may comprise an environment of nitrogen and a
ventilated
chamber 242 such that the pellets equalize with the environment. The
ventilated chamber 242 may
be heated to a set temperature using a burner array 244 that, in this aspect,
combusts a syngas
provided by a syngas tank 246. A temperature within the ventilated chamber 242
may be measured
using one or more thermocouples (not shown). A controller may receive the
temperature
.. measurements and may control the burner array 244 in order to maintain the
set temperature within
the ventilated chamber 242 in order to pyrolyze the suitable pellets into one
or more clay-biocarbon
composite pellets. In this aspect, the temperature may be maintained between
400 C and 900 C
and, as previously mentioned, may be for a time period between 20 to 100
minutes. The
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temperature and the time period may be dependent on the particular volatile
compounds 260, in
this aspect a syngas, emitted from the suitable pellets within the thermal
chamber 240. For
example, the suitable pellets may have a high oil content and may require an
increased duration of
thermal processing to remove all of the oil from the SBE.
[0033] In some aspects, the volatile compounds 260 emitted from the ventilated
chamber 242 may
be condensed using a condenser 262 to produce a condensate 264. The condensate
264 may be
further processed to produce a pyrolysis oil stored within an oil tank 268. A
water condenser 266
may be used to remove water from the syngas 260 to produce a renewable gaseous
fuel that may
be drawn off using a vacuum pump 270 and stored within the syngas tank 246.
100341 In some aspects, a syngas secondary chamber 248 may be used and heated
to approximately
*1 100 C . The syngas secondary chamber 248 may introduce a syngas such as
hydrogen, carbon
monoxide, methane or combination thereof to the ventilated chamber 242 in
which toxins are
destroyed within the syngas. The introduction of the syngas may introduce
carbon monoxide to
the ventilated chamber 242 that may react with the contaminants, the volatile
components, and/or
the oil within the suitable pellets. A flue gas may exit the ventilated
chamber 242 using an exhaust
249. The flue gas may be used to purge the discharge auger 252 as described
below. When there
is excess syngas, the syngas may be flared using a flare 247.
[0035] The clay-biocarbon composite pellets may then exit the thermal chamber
240 in an airtight
manner via a retort collection auger 250. One or more samples of the clay-
biocarbon composite
pellets may be taken from the collection auger 250 for analysis. The
collection auger 250 may
then deposit the clay-biocarbon composite pellets into a discharge auger 252
in an airtight manner.
The discharge auger 252 may have been purged of oxygen using the flue gas
and/or nitrogen 254
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to
via one or more valves (not shown). The collection auger 250 and the discharge
auger 252 may
comprise an atmosphere substantially devoid of oxygen until the clay-biocarbon
composite pellets
are cooled to room temperature and/or below a spontaneous combustion
temperature. The clay-
biocarbon composite pellets may then be inspected and, if suitable, be
packaged for use, otherwise,
the clay-biocarbon composite pellets may be returned to step 130 to be used as
one of the filler
compounds.
[0036] With reference to Table 2 below, the processes and systems 100, 200 as
described herein
may transform a viscous SBE into raw SBE pellets. The pyrolysis of these SBE
pellets produces
clay-biocarbon composite pellets with many applications such as adsorption,
filtration, and
decolorizing edible oils. Raw SBE pellets and their composites are not
suitable as they are already
spent (partially or fully saturated with oil). However the pyrolyzed SBE and
the SBE composites
can be used for adsorption, filtration, and decolorizing edible oils. The
results of odour testing
completed with pyrolyzed SBE and SBE composites is presented in Table 2
hereinafter.
Table 2: Odour testing of various raw and pyrolyzed pellets
Raw Pellet composition Pelletability Odour
Pyrolyzed Product
Sample Control
(Not .1),,rolyzed) (% Comments
Score
Hard, not water ii ,
1 M.', Clay 76.98
soluble Success
Softer, more
12
2 SBE Clay + wood 85.1 powder, not water
Success
soluble
Hard, not water 9,
3 SHE Clay + biocarbon 82.33
soluble Success
Solic,T, more
SBF, Clay
4 84.96 powder, not water
wood Marginal
soluble
Non SUE Clay + 84 1 hard, not water
5 .3 1, Fail
biocarbon + Zeolite soluble
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[00371 The foregoing is considered as illustrative only of the principles of
the invention. Further,
since numerous changes and modifications will readily occur to those skilled
in the art, it is not
desired to limit the invention to the exact construction and operation shown
and described, and
accordingly, all such suitable changes or modifications in structure or
operation which may be
resorted to are intended to fall within the scope of the claimed invention.
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