Note: Descriptions are shown in the official language in which they were submitted.
CA 02675940 2010-12-08
BASIC SOP PROCESS FOR RECOVERY OF OLIGOSACCHARIDES AND
POLYSACCHARIDES FROM PLANTS
Background of Invention
The first man-made writing/drawing paper was produced by early Egyptians from
the
lowermost stem parts of papyrus, a sedge that grows up to 5 m in height, using
a semi-
pulping process involving stem slicing, pounding, cross-lapping and drying.
Thus, the
word "paper" is derived from the Greek and Latin words papuros and papyrus,
respectively.
The production of paper from papyrus was successful because of the natural
ability of
polysaccharides which are present in cell walls of all vascular plants to bond
together upon
drying, even when the plant tissue's adjoining fibres remained as discrete
strips of tissue
(i.e., not pulped). However, "true' paper is made from plant tissues that have
been reduced
to their individual fibres (i.e., fully pulped) and then re-constituted from a
fibrous pulp
suspension. (Hunter, D. 1947, Papermalcing, Dover Publications, New York).
True paper was being produced manually in China as early as the 2nd century
BC, by
manually pounding wetted cloth rags, bark of trees or shrubs, soft plant stems
and leaves to
a pulp, using a screen to lift the pulp out of the vat and produce a wet
layer, followed by
pressing moisture out of the wet layer and then hanging and drying that
'sheet' to produce
paper. Papers of outstanding quality were produced from such plant tissues
(Tsien, T.-H.
1973, Journal of the American Oriental Society 93:510). Centuries later, in
1800, the Great Seal
Patent office, London, granted Matthias Koops a patent "...for a method of
manufacturing
paper from straw, hay, thistles, waste, and ruse of hemp and flax, and
different kinds of
wood and bark," again an indication that any tissue of any plant may serve for
production
of paper.
Wood as it occurs in trees and vascular plants in general is, in comparison to
other plant
tissues, a relatively hard bulky dark and inflexible material. Therefore,
although wood is
presently the dominant tissue of plants used in papermaking, woody stems were
likely
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considered unsuitable as a material to be manually pounded into pulp at the
outset of
papermaking.
The first suggestion to utilize wood for paper-making may have been in 1719 by
Rene
Antoine Ferchault de Reaumur following his observations of the delicate papery
nests
created by American and Canadian wood wasps. Nevertheless, it was not until
1765 that
Jacob Christian Schaffer made papers from pulp of beech, willow, aspen,
mulberry, spruce
and other woods, each paper being produced from wood pulp in admixture with
rag fibres.
Schaffer also noted that wood treated with a lime paste required less time and
energy to beat
into pulp than untreated wood, and this evidently was the first step toward
chemical
pulping of wood.
The first paper made exclusively of wood pulp appears to have been a single
page made of
elm-wood fibres, produced in 1786 by Leorier Delisle and placed into a book
authored by
Charles Michel de Villette. In 1798 Nicolas-Louis Robert constructed a moving
screen belt
capable of receiving a continuous flow of suspended pulp and delivering an
unbroken sheet
of wet paper to a pair of squeeze rolls where most of the residual liquid was
removed from
the adjoining fibres. That innovation set the stage for mass production of
paper hence the
demand for larger quantities of pulp than could be produced manually. In 1840
Friedrich
Keller secured a German patent for grinding logs against a millstone and, in
1867, ground-
wood pulp was being produced in Massachusetts in order to make newsprint
solely from
wood fibres.
Newsprint as produced from chemically untreated ground wood was dull, darkened
quickly and was not very strong, and the desire to produce stronger brighter
paper from
wood led to investigations into chemical pulping. The first chemical pulping
of wood to
operate on the industrial scale was the soda process, so-named because it used
sodium
hydroxide (NaOH) as the alkaline solution for cooking the wood pieces at
elevated
temperature and pressure. The soda process was developed in 1851 by Hugh
Burgess and
Charles Watt in England, and they secured a patent in the United States for
the process in
1854. Alkaline sulfite pulping was patented in 1867 by Benjamin Tilghman in
the United
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States, and Kraft pulping was patented in 1884 by Carl Dahl of Germany. Many
variations
on those chemical pulping processes have subsequently been described, and
innumerable
patents exist or existed in relation to their modifications. One variation
presently invoking
considerable interest is known as ASAM pulping (alkaline sulfite with
anthraquinone and
methanol as catalysts) as described by Patt and Kordsachia (1986, Das Papier
40 (10A):V1).
All chemical and related pulping processes are concerned with one or more
direct or
ancillary aspects involving treatment of wood particles with harsh chemicals
at high
temperature and pressure for many hours, the aim being to break the chemical
bonds
between cell-wall macromolecules such as lignin, hemicelluloses and cellulose
in order that
the individual plant cells, often referred to as 'fibers' in the pulping
industry, can exist
independently in suspension. The cell walls in non-woody plant tissues also
contain
hemicelluloses and cellulose but with little or no lignin present. Because
chemical methods
of wood pulping require the wood particles known as chips to be treated for
several hours
above atmospheric pressure at a temperature above the boiling point
(approximately 100 C)
of the cooking liquor, a generally massive pressure cooker known as a
'digester' is the
starting point of industrial pulping. Under the conditions associated with
cooking particles
of plants with a high concentration of alkali at high temperature and a
pressure above
atmospheric within a digester, not only lignins but also hemicelluloses are
hydrolyzed or
otherwise chemically modified and released into the cooking liquor as smaller,
soluble
molecules.
The present invention embodies a practicable industrial process for obtaining
a mixture of
solid oligosaccharides and polysaccharides (SOP) in major quantity not only
from raw wood
but also from other plant tissues. The basic SOP process as specified and
claimed herein
may be implemented a s a pre-pulping sub-process carried out in a pulp-mill
digester;
alternatively, it may operate independently of the pulping industry. The basic
SOP process
operates at atmospheric pressure, and the temperature of the alkaline solution
soaking the
plant tissue in the pulp-mill digester or other extraction vessel may be as
low as 4 0C and in
any case is kept below the boiling point in order to reduce hydrolytic
breakdown of SOP
molecules.
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The basic SOP process requires the availability of large volumes of an
aliphatic alcohol such
as methanol or ethanol in order to coagulate and further process the
oligosaccharides and
polysaccharides of SOP. Coincidentally, wood was used commercially as early as
1830 to
produce methanol through the process of destructive distillation. In recent
years, wood
hemicelluloses have been identified as important substances for fermentative
production of
ethanol. Thus, there exists opportunity for the industry of the basic SOP
process to
concomitantly operate a supporting process enabling it to be a producer rather
than a
consumer of the needed aliphatic alcohol(s).
Various patents related to ethanol production from sugars produced through
hydrolysis of
hemicelluloses have been filed in recent years. However, to the best of my
knowledge none
of those patents has addressed development of an industrial process such as
described
herein, for using aliphatic alcohol to obtain from alkaline extracts of woody
or non-woody
tissue of plants oligosaccharides and polysaccharides.
The use of an aliphatic alcohol to coagulate or "precipitate" polysaccharides
in an alkaline
solution gained acceptance as a routine scientific method, of common knowledge
in the
public domain, early in the 20th century (e.g., Norris, F.W. and Preece, I. A.
1930,
Biochemistry Journal 24:59; Sands, L. and Gary, W. Y. 1933. Journal of
Biological Chemistry
101:573; Adams, G.A. and Castagne, A.E. 1951, Canadian Journal of Chemistry
29:109).
Following upon that scientific advance, several patents were nevertheless
awarded
specifically in relation to use of an aliphatic alcohol, such as ethanol, to
precipitate
"hemicelluloses" from alkaline extracts of plant tissues. For example, U.S.
patent 3,935,022
for the manufacture of viscose products claimed "a process for removing
hemicelluloses
from hemicellulose-containing alkali solution consisting essentially of adding
to said alkali
solution a sufficient amount of a solvent consisting essentially of ethanol to
precipitate
hemicellulose from said alkali solution..." Similarly, U.S. patent 7,101,996
claimed "a
process for the separation of purified hemicelluloses from insoluble cellulose
and cellulose-
hemicellulose complexes in caustic liquor from solubilizing fiber with alkali
comprising the
steps of adding alcohol to the caustic liquor to precipitate the
hemicelluloses..." As noted,
the supposed inventions underlying those claims were in the public domain well
before the
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patent applications were filed, and more fundamentally the details of
practicable industrial
processes were not specified as such within those patents. In addition, there
has been a
tendency in the patent literature for the term 'hemicellulose' to be used
without clear
definition, although the meaning of the term can be more rigorously
interpreted. (Aspinall,
G. 0. 1970, Polysaccharides. Pergamon Press, Oxford; Wilkie, K.C.B. 1985, pp 1-
37, in
Biochemistry of Plant Cell Walls, edited by C.T. Brett and J. R. Hillman,
Cambridge U. Press).
As noted by Wilkie (1985, p 3 in Biochemistry of Plant Cell Walls, edited by
C.T. Brett and J. R.
Hillman, Cambridge U. Press), "Confusion and uncertainty is caused when terms
are used
that are ill-defined or, as in the case of hemicelluloses, when terms have
considerable, and
unrecognized, variability in their definition." Recognizing that the
oligosaccharides and
polysaccharides of the SOP process have their origin in native hemicelluloses
(in agreement
with the fact that cotton fibres, known to contain almost pure cellulose,
yield almost no SOP
within the basic SOP process) which are well established to comprise a
variable, large and
incompletely known number of oligosaccharides, oligosaccharide derivatives,
polysaccharides and polysaccharide derivatives, the process taught here
deliberately avoids
referring to them as hemicelluloses.
The embodiments of the basic SOP process require that a distinction be made
between the
natural hemicelluloses and the oligosaccharides and polysaccharides obtained
by the SOP
process. Aqueous alkaline treatment of plant tissues not only hydrolyzes into
smaller
molecules those polysaccharides referred to as hemicelluloses but also
saponifies the natural
esters (e.g., acetyl or diferulyl groups) natural to those polysaccharides. In
other words,
alkali extraction changes the true or 'native' polysacchardies of plants into
de-esterified
polysaccharides and shorter oligosaccharides differing in both chemical
properties and
chain length from those occurring naturally. (Neilson, M.J. and Richards, G.
N. 1978, Journal
of the Science of Food and Agriculture 29:513). One way to understand the
distinction is to
consider the solubility of native hemicelluloses vis-d-vis solid
oligosaccharides and
polysaccharides obtained by the basic SOP process. In general native
hemicelluloses are not
misicible in water and will produce a cloudy suspension rather than a clear
solution when
mixed with cool or lukewarm water. SOP, on the other hand, upon mixing with
water at
sub-ambient or higher temperature, readily provides a clear solution of
oligosaccharides and
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polysaccharides. Dialysis using M.W. 10,000 cut-off has nevertheless revealed
that the
molecules in the clear solution are miscible in water. In other words, the
colligative
properties of SOP are different from those of native hemicelluloses.
In developing this invention referred to as the basic SOP process, a variety
of woody and
non-woody plant species was investigated. Based on the findings, it is
suggested that all
plants will yield some amount of SOP when subjected to the basic SOP process.
However,
the yield clearly varies among species, with Magnoliophyta in general
providing more SOP
than Coniferophyta. Of the species investigated, bamboo stems yielded the most
SOP, raw
fibres from cotton bolls the least. It is apparent from Table 12 in the
example given that
common roadside weeds may be excellent sources of SOP.
Potential end uses of SOP are not the subject of this Specification because
those end uses
remain to be determined and are expected to vary depending on the plant
species and tissue
used to produce the SOP. In general, SOP is expected to be useful in a variety
of
applications including production of novel kinds of paper, as sizing or other
paper additive,
as digestive fiber, as chewing and other gums, as foodstuffs (e.g., syrup,
sweetener) for both
animals and humanity, as a bulking agent in pharmacy, as carbohydrate in
support of
fermentation, and for energy production.
The novelty of the SOP process goes beyond linking together a series of
existing
technologies in the correct sequence needed to provide large quantities of SOP
for use in
various commercial production streams. In relation to wood pulping, the black
liquor
issuing from the digester after processing wood chips contains not only
sulfonated lignin
derivatives but also sulfonated and otherwise chemically modified compounds
derived
from the hemicellulose fraction (Niemela, K. 1990. Annales Academiae
Scientiarum Fennicae,
Series A, II. Chemica 229). By removing soluble and/or miscible
oligosaccharides and
polysaccharides from wood chips at the beginning of the pulping process, a
significant
fraction of the biomass is prevented from contributing to the black liquor
stream and,
additionally, the remaining wood chips are effectively primed with alkali from
the SOP
soak(s) enabling subsequent pulping to proceed more efficiently. In relation
to tissues from
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plants not classified as trees, such as agricultural plants, weeds, bamboos,
and also bark and
other tissues of trees, although all were established ages ago to be useful
sources of pulp
particularly for production of high quality grades of paper in industrial
pulping those
species have been supplanted by trees primarily because of the ready
availability of massive
quantities of more or less uniform wood tissue within tree stems. However, the
SOP process
adds a new dimension to the utilization of non-wood plant tissues, as it
enables production
of both SOP and useful pulp-and-paper fibres in a sequential process
regardless of the plant
species.
DETAILED DESCRIPTION
The basic SOP process claimed herein produces solid oligosaccharides and
polysaccharides
from natural chemical substances resident within tissues of plants. The
process begins in
any extraction vessel capable of being loaded with and containing pieces of
raw plant tissue
and primary soaking solution. These pieces of raw plant tissue may be of
dimensions up to
or less than 10 mm in thickness, 10 mm in width and 50 mm in length. Within
those
dimensional constraints, the precise thickness, width and length of said
pieces of raw plant
tissue loaded into said extraction vessel are variables which may be modified
in order to
optimize the efficiency and productivity of said basic SOP process in relation
to the species
of raw plant tissue and the conditions and equipment available.
Although said basic SOP process does not require a pulp-mill digester to serve
as said
extraction vessel, said basic SOP process can readily be accomplished as the
first phase of the
overall pulping process as carried out within a pulp-mill digester,
particularly if said
digester is used for soda, alkaline sulfite, Kraft or ASAM chemical, semi-
chemical or chemi-
mechanical pulping. Performing said basic SOP process in association with
pulping enables
more complete utilization of said pieces of raw plant tissue, increase in
overall yield of
economically useful products, and reduction in the amount of substances
contributing to the
so-called "black liquor" resulting from the so-called "cook" done in the pulp-
mill digester at
above ambient pressure and elevated temperature in order to convert the raw
plant tissue
into its individual fibres.
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Said primary soaking solution consists of a known concentration, ranging from
0.5 - 10 M, of
an alkaline hydroxide in aqueous solution, and said primary soaking solution
is provided to
said extraction vessel in sufficient or greater volume needed to achieve a
soak, here
designated as primary soak, of all said pieces of raw plant tissue in said
extraction vessel for
the full duration of primary soaking time selected from within the range 0.1 -
4.0 hours at a
temperature selected from within the range 4 - 100 C. The species of said
alkaline
hydroxide may be lithium hydroxide, potassium hydroxide or sodium hydroxide.
The
species and concentration of said alkaline hydroxide, the precise duration of
said primary
soaking time, and the precise temperature(s) of said primary soaking solution
used during
said primary soaking time are, within the stated bounds, variables which may
be modified
in order to optimize the efficiency and productivity of said basic SOP process
in relation to
the species of raw plant tissue and the conditions and equipment available.
Following elapse of said primary soaking time, said primary soaking solution
is displaced
from the insoluble residue of said pieces of raw plant tissue remaining in
said extraction
vessel using gravity flow, positive pressure or vacuum expulsion to expel the
recoverable
volume of said primary soaking solution, here designated as primary
recoverable volume,
into conduit(s) running from said extraction vessel to SOP-forming tank. Said
primary
recoverable volume is transferred within said conduit(s) from said extraction
vessel into said
SOP-forming tank using valves and pumps as necessary. Said primary recoverable
volume
is retained in said SOP-forming tank until the temperature of the liquid of
said primary
recoverable volume is measured to be at or below 40 oC, hereafter designated
as ambient
temperature.
Said SOP-forming tank operates at ambient pressure (i.e., the pressure of the
surrounding
air) and said ambient or lower temperature and is equipped with several
devices, viz., a
device for accurately measuring and indicating the volume of contained liquid
within said
SOP-forming tank, a refrigeration unit for cooling the internal environment,
with
thermometers for accurately measuring the temperature of said contained liquid
and air
above said contained liquid, with mechanism(s) to stir and/or mix said
contained liquid,
with intake and outlet ports and pumps for receiving and discharging liquids
and fluid
suspensions, respectively, and with devices needed to regulate rates of
stirring and/or
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mixing, receiving and discharging of both incoming liquids and outward flowing
suspensions. The precise operating temperature of said SOP-forming tank is a
variable
which may be modified in order to optimize the efficiency and productivity of
said basic
SOP process in relation to the species of raw plant tissue and the conditions
and equipment
available.
An aliphatic alcohol in liquid state of at least 95% purity and containing by
volume 5% or
less water, and pre-chilled to a temperature at least 10 0C below its flash
point is transferred
within conduit(s), using valves and pumps as necessary, from an alcohol
storage tank into
said SOP-forming tank containing said primary recoverable volume. Suitable
species of said
aliphatic alcohol include ethanol, methanol, 2-propanol or n-butanol. Said
aliphatic alcohol
is added to said primary recoverable volume until the total volume of liquid
contained in
said SOP-forming tank is twice, within volumetric precision of 2%, that of
said primary
recoverable volume. Said total volume of liquid contained in said SOP-forming
tank is
mixed for a time, here designated as primary mixing time, selected from the
range 1 - 30
minutes, the duration of said primary mixing time being sufficient to achieve
uniform
mixing thus producing a 1:1 (v/v) homogeneous mixture, here designated as
primary
mixture, of said primary recoverable volume and the equivalent volume of said
aliphatic
alcohol. After elapse of said primary mixing time, said primary mixture is
held static at said
ambient temperature and said ambient pressure in said SOP-forming tank for a
setting time,
here designated as primary setting time, selected from the range 0.1 - 24
hours. During the
course of said primary setting time, a fluid suspension of coagulated
substances containing
oligosaccharides and polysaccharides, and here designated as primary
suspension, forms.
The species of said aliphatic alcohol, the precise duration of said primary
mixing time and
the precise duration of said primary setting time are, within the stated
bounds, variables
which may be modified in order to optimize the efficiency and productivity of
said basic
SOP process in relation to the species of raw plant tissue and the conditions
and equipment
available.
After elapse of said primary setting time, said primary suspension in said SOP-
forming tank
is stirred or mixed continuously for a time, here designated as primary
stirring time, at said
ambient temperature and said ambient pressure to produce a dispersed primary
suspension.
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Said primary stirring time is whatever length of time is required to transfer
the entire
volume of said dispersed primary suspension generated from said primary
recoverable
volume and the equivalent volume of added said aliphatic alcohol out of said
SOP-forming
tank, conveying it using pumps as necessary from said SOP-forming tank at a
controlled
flow rate within non-valved conduit(s) to the inlet of a device, here
designated as SOP
separator, operating at said ambient or lower temperature and said ambient or
lower
pressure and capable of performing the processes of separating SOP from
liquid, retaining
and accumulating cakes of primary SOP, and concomitantly expelling liquid here
designated as primary waste solution from said SOP separator. Said process of
separating
SOP from liquid, retaining and accumulating said cakes of primary SOP, and
concomitantly
expelling said primary waste solution requires use in said SOP separator of a
filter and
backing support, this filter and backing support here designated as SOP
filter. Said SOP
filter must be cellulose based and must not retain particles smaller than 1.0
um.
20
Said controlled flow rate of said dispersed primary suspension from said SOP-
forming tank
into said SOP separator is adjusted to be equal to or less than that of the
outflow rate from
said SOP separator of said primary waste solution. Said controlled flow rate
is to ensure
that said dispersed primary suspension within said conduit(s) between said SOP-
forming
tank and said SOP separator is maintained as nearly as possible as a uniformly
dispersed
suspension during its inflow into said SOP separator. Said primary waste
solution upon
exiting said SOP separator is transferred within conduit(s), using pumps and
valves as
necessary, to a storage tank in support of its subsequent distillation, said
distillation being to
recover said aliphatic alcohol.
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Said SOP separator has inlet(s) that may be opened or closed and outlet(s)
that may be
opened or closed to permit said dispersed primary suspension or other liquid
to enter and
exit, respectively and, if of the centrifuge type, said SOP separator must be
able to generate
centripetal forces between 0 X g and 500 X g. The processes of SOP cake
formation from said
dispersed primary suspension followed by washing, bleaching and dehydration
are
specified here as they would proceed using as said SOP separator a stainless
steel vertical
basket centrifuge and using as said SOP filter a removable cellulosic filter
bag and stainless
steel wire mesh backing against a stainless steel perforated vertical basket.
It will be apparent that other devices could serve as SOP separator and other
kinds of filter
and backing as SOP filter, and the intention here is not to limit innovation
in this realm of
said basic SOP process. There are many kinds of centrifuges and centrifuge
filters used in
chemical, pharmaceutical, food and textile industries which are candidates for
said SOP
separator used in said basic SOP process. Alternatively, a positive pressure
combined
filtration cake-drying system, a vacuum filtration system, a gravity-flow
filtration system, or
even a suitably modified clothes washing machine fitted with said SOP filter
could serve as
said SOP separator.
Insoluble substances within said dispersed primary suspension are accumulated
as a cake of
primary SOP within the bounds delimited by said SOP filter within said
vertical basket
while clear liquid constituting said primary waste solution concomitantly
passes through
said SOP filter and exits said SOP separator operating at said ambient or
lower temperature
and conditions of pressure intrinsic to said SOP filter and said SOP
separator. The rate at
which said SOP cake number one accumulates and said primary waste solution
exits is
regulated by changing the angular velocity of said vertical basket such that
it provides a
constant centripetal force selected from within the range of 1 X g to 500 X g.
The precise
operating temperature and the precise said constant centripetal force of said
SOP separator
may be modified in order to optimize the productivity of said basic SOP
process in relation
to the species of raw plant tissue and the conditions and equipment available.
Accumulation of a cake of primary SOP within said vertical basket providing
said constant
centripetal force continues until the volume of said cake of primary SOP
within said SOP
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filter is 50% or less of the volumetric capacity of said vertical basket,
whereupon outflow of
said primary dispersed suspension from said SOP-forming tank is stopped. Said
vertical
basket providing said constant centripetal force continues accumulating said
cake of
primary SOP until the volume of said primary dispersed suspension remaining in
said
conduit(s) between said SOP-forming tank and said SOP separator has been
drained and
washed from within said conduit(s) into said SOP separator, thus producing
clean
conduit(s). After draining said conduit(s) of said primary dispersed
suspension, said clean
conduit(s) is produced by introducing into said conduit(s) at its point of
departure from said
SOP-forming tank primary washing solution comprising 1:1 (v/v) mixture of
water and said
aliphatic alcohol in sufficient volume to clean said conduit(s) of said
primary dispersed
suspension, allowing said primary washing solution to flow into and out of
said SOP
separator, using pumps as necessary. The moment said clean conduit(s) has been
produced,
the rate of spinning of said vertical basket is decelerated to angular
velocity equal to zero.
Said cake of primary SOP is converted into bleached SOP here designated as
bleached
primary SOP by bleaching said cake of primary SOP contained within said
vertical basket
within said SOP separator for a bleaching time, here designated as primary
bleaching time,
selected from the range 0.2 - 1.0 hour at said ambient or lower temperature
and said
ambient pressure. Immediately prior to the start of said primary bleaching
time, said outlet
of said SOP separator is closed and bleaching solution, here designated as
primary bleaching
solution and comprising by volume a percentage of hydrogen peroxide selected
from the
range 3 - 10%, 50% 5% by volume said aliphatic alcohol and the balance
water, is
introduced at said ambient temperature into said vertical basket in sufficient
volume to fill
said SOP separator to its operational capacity. Within said range 3 - 10%, the
combined
volume percentages of said hydrogen peroxide and said water in said primary
bleaching
solution must add to 50% 5% of the total volume of said primary bleaching
solution. The
precise duration of said primary bleaching time and the precise percentages of
said
hydrogen peroxide and water within said primary bleaching solution are
variables which
may be modified in order to optimize the efficiency and productivity of said
basic SOP
process in relation to the species of raw plant tissue and the conditions and
equipment
available.
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After elapse of said primary bleaching time, said outlet of said SOP separator
is opened and
expelling of used said primary bleaching solution, here designated as used
primary
bleaching solution, is begun. During the process of said expelling of said
used primary
bleaching solution, the angular velocity of said vertical basket is
accelerated to a constant
centripetal force, selected from within the range of 1 X g to 500 X g,
continuing to expel said
used primary bleaching solution from said SOP separator while the angular
velocity of said
vertical basket increases and thereafter for five additional minutes of
operation of said
vertical basket providing said constant centripetal force, thus achieving the
goal of
producing said bleached primary SOP. Said used primary bleaching solution as
expelled
from said SOP separator is conveyed within conduit(s), using pumps and valves
as
necessary, to a suitable storage tank in support of its subsequent
distillation, said distillation
being to separate and recover said aliphatic alcohol. The precise centripetal
force of said
constant centripetal force used to expel said used primary bleaching solution
from said SOP
separator is a variable which may be modified in order to optimize the
efficiency and
productivity of said basic SOP process in relation to the species of raw plant
tissue and the
conditions and equipment available.
Said bleached primary SOP spinning within said vertical basket providing said
constant
centripetal force is rinsed for a rinsing time selected from the range five to
thirty minutes
using a continuous spray of rinsing solution here designated as primary
rinsing solution and
comprising 1:1 (v/v) mixture of water and said aliphatic alcohol, used said
primary rinsing
solution here designated as used primary rinsing solution being expelled from
said SOP
separator throughout said rinsing time and conveyed from there within
conduit(s), using
valves and pumps as necessary, to a suitable storage tank in support of its
subsequent
distillation, said distillation being to separate and recover said aliphatic
alcohol. Said
primary rinsing solution has a temperature lower than said ambient
temperature, and the
flow rate of incoming said primary rinsing solution is the same or lower than
the flow rate of
outgoing said used primary rinsing solution. The precise duration of said
rinsing time, the
precise temperature of said primary rinsing solution and the precise flow rate
of incoming
said primary rinsing solution are variables which may be modified in order to
optimize the
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efficiency and productivity of said basic SOP process in relation to the
species of raw plant
tissue and the conditions and equipment available.
Said bleached primary SOP spinning within said vertical basket providing said
constant
centripetal force is converted into partially dehydrated SOP, here designated
as bleached
dehydrated primary SOP, by treating said bleached primary SOP with said
aliphatic alcohol
containing 5% or less water content, here designated as dehydration alcohol.
Said bleached
primary SOP spinning in said vertical basket providing said constant
centripetal force is
sprayed for five minutes with said dehydration alcohol pre-chilled to a
temperature at least
10 0C below the flash point of said dehydration alcohol and, at the moment of
spraying,
having a temperature lower than said flash point. The flow rate of incoming
said
dehydration alcohol is the same or lower than the flow rate of outgoing said
dehydration
alcohol, here designated as used dehydration alcohol, that is concomitantly
expelled as said
used dehydration alcohol from said SOP separator. The precise temperature of
said
dehydration alcohol and the precise flow rate of incoming said dehydration
alcohol are
variables which may be modified in order to optimize the efficiency and
productivity of said
basic SOP process in relation to the species of raw plant tissue and the
conditions and
equipment available. Following completion of said spraying, said bleached
primary SOP is
spun in said vertical basket providing said constant centripetal force for
five additional
minutes while continuing to expel said used dehydration alcohol from said SOP
separator
and from there via conduit(s), using valves and pumps as necessary, to a
suitable storage
tank in support of its subsequent distillation, said distillation being to
separate and recover
said aliphatic alcohol. Said vertical basket is then decelerated to zero
angular velocity, and
said bleached dehydrated primary SOP and said SOP filter are removed from said
SOP
separator for storage or further processing as desired.
Said bleaching of said cake of primary SOP may be useful in relation to the
intended end
product but is non-essential for SOP production per se. When it is elected not
to do said
bleaching, said cake of primary SOP contained in said SOP filter within said
vertical basket
of said SOP separator is converted directly into washed primary SOP by washing
said cake
of primary SOP at said ambient or lower temperature and said ambient or lower
pressure
14
CA 02675940 2010-12-08
with washing solution, here designated as primary washing solution and
comprising 1:1
(v/v) mixture of water and said aliphatic alcohol for a primary washing time
selected from
the range 0.2 - 1.0 hour. The precise temperature of said ambient or lower
temperature, the
precise pressure of said ambient or lower pressure, and the precise duration
of said primary
washing time are variables which may be modified in order to optimize the
efficiency and
productivity of said basic SOP process in relation to the species of raw plant
tissue and the
conditions and equipment available. To initiate said washing, the outflow
valve of said SOP
separator is closed, and said primary washing solution at said ambient or
lower temperature
is introduced into said SOP separator in sufficient volume to fill said SOP
separator to its
operational capacity. Once filled to said operational capacity, the outlet of
said SOP
separator is opened, and expelling of used said primary washing solution, here
designated
as used primary washing solution, is begun. After start of said expelling of
said used
primary washing solution, the angular velocity of said vertical basket is
accelerated until
said vertical basket provides a constant centripetal force selected from
within the range of 1
X g to 500 X g, continuing to expel said used primary washing solution
throughout the
acceleration period and for five additional minutes after said constant
centripetal force has
been achieved. The precise said constant centripetal force used after said
start of said
expelling of said used primary washing solution may be modified in order to
optimize the
productivity of said basic SOP process in relation to the species of raw plant
tissue and the
conditions and equipment available.
Following elapse of said five additional minutes, said cake of primary SOP in
said vertical
basket providing said constant centripetal force is subjected for the
remainder of said
primary washing time to a continuous spray of said primary washing solution to
generate
washed primary SOP and used primary washing solution, expelling throughout
that time
from said SOP separator said used primary washing solution. Said used primary
washing
solution is conveyed after said expelling within conduit(s), using valves and
pumps as
necessary, to a suitable storage tank in support of its subsequent
distillation, said distillation
being to separate and recover said aliphatic alcohol.
15
CA 02675940 2010-12-08
Said washed primary SOP is converted into partially dehydrated primary SOP,
here
designated as dehydrated primary SOP, by spraying said washed primary SOP in
said
vertical basket providing said constant centripetal force for five minutes
with said
dehydration alcohol pre-chilled to a temperature at least 10 0C below the
flash point of said
dehydration alcohol. The flow rate of incoming said dehydration alcohol is the
same or
lower than the flow rate of outgoing said used dehydration alcohol that is
concomitantly
expelled as said used dehydration alcohol from said SOP separator. The precise
temperature of said dehydration alcohol and the precise flow rate of incoming
said
dehydration alcohol are variables which may be modified in order to optimize
the efficiency
and productivity of said basic SOP process in relation to the species of raw
plant tissue and
the conditions and equipment available. Following completion of said spraying,
said
washed primary SOP is spun in said vertical basket providing said constant
centripetal force
for five additional minutes while continuing to expel said used dehydration
alcohol from
said SOP separator within conduit(s), using valves and pumps as necessary, to
a suitable
storage tank in support of its subsequent distillation, said distillation
being to separate and
recover said aliphatic alcohol. Said vertical basket is then decelerated to
zero angular
velocity, and said dehydrated primary SOP and said SOP filter are removed from
said SOP
separator for storage or further processing as desired.
Following transfer of said entire volume of said dispersed primary suspension
from said
SOP-forming tank to said SOP separator during production of said cakes of
primary SOP,
the walls of said SOP-forming tank are washed to produce clean SOP-forming
tank. Said
clean SOP-forming tank is produced by washing the walls of said SOP-forming
tank with
said primary washing solution at said ambient or lower temperature and of
volume no less
than three times the volume contained by those said non-valved conduit(s) used
to transfer
said dispersed primary suspension from said SOP-forming tank to said SOP
separator.
While washing said walls of said SOP-forming tank, said primary washing
solution is
expelled from said SOP-forming tank via said outlet ports of said SOP-forming
tank into
said non-valved conduit(s) and transferred through said non-valved conduit(s)
to and
through said inlet(s) into said SOP separator at a flow rate regulated to
match the rate of
removal of liquids from said outlet(s), using pumps as necessary. After said
washing of said
16
CA 02675940 2010-12-08
walls of said SOP-forming tank with said primary washing solution and
expelling of said
primary washing solution from said SOP-forming tank, cleaning of said non-
valved
conduit(s) between said SOP-forming tank and said SOP separator is done. Said
cleaning is
accomplished by introducing into said SOP-forming tank and said outlet ports
of said SOP-
forming tank said primary washing solution at said ambient or lower
temperature and of
volume no less than three times the volume contained by those said non-valved
conduit(s)
used to transfer said dispersed primary suspension from said SOP-forming tank
to said SOP
separator at a flow rate regulated to match the rate of removal of liquids
from said outlet(s),
using pumps as necessary.
After completion of said cleaning, said non-valved conduit(s) between said SOP-
forming
tank and said SOP separator is disconnected from said inlet(s) leading into
said SOP
separator, and flushing of said SOP-forming tank and said non-valved
conduit(s) is done.
Said flushing is accomplished by introducing into said SOP-forming tank liquid
water
having a temperature below the boiling point for outflow of said liquid water
through said
outlet ports of said SOP-forming tank hence through said non-valved
conduit(s). Said
flushing is continued until clear water flows freely from the disconnected
end(s) of said non-
valved conduit(s).
Following removal of said primary soaking solution from said extraction vessel
to said SOP-
forming tank for production of said primary suspension, said insoluble residue
remaining in
said extraction vessel is subjected for a time to a second soak by fully
immersing said
insoluble residue in a secondary soaking solution at said ambient temperature
and said
ambient pressure to yield a second extract for conveyance to and production
within said
SOP-forming tank or its equivalent of a secondary suspension for processing
into additional
cakes of SOP here designated as cakes of secondary SOP. Said secondary soaking
solution
consists of a known concentration, ranging from 0.5 - 10 M, of an alkaline
hydroxide in
aqueous solution. The species of said alkaline hydroxide may be lithium
hydroxide,
potassium hydroxide or sodium hydroxide. Said secondary soaking solution is
provided to
said extraction vessel in sufficient or greater volume needed to achieve a
soak, here
designated as secondary soak, of all said insoluble residue in said extraction
vessel for the
17
CA 02675940 2010-12-08
full duration of secondary soaking time selected from within the range 0.1 -
4.0 hours at a
temperature selected from within the range 4 - 100 C. The species and
concentration of
said alkaline hydroxide, the precise duration of said secondary soaking time,
and the precise
temperature(s) of said secondary soaking solution used during said secondary
soaking time
are, within the stated bounds, variables which may be modified in order to
optimize the
efficiency and productivity of said basic SOP process in relation to the
species of raw plant
tissue and the conditions and equipment available.
Following elapse of said secondary soaking time, said secondary soaking
solution is
displaced from said insoluble residue remaining in said extraction vessel
using gravity flow,
positive pressure or vacuum expulsion to expel the recoverable volume of said
secondary
soaking solution, here designated as secondary recoverable volume, into
conduit(s) running
from said extraction vessel to said SOP-forming tank. Said secondary
recoverable volume is
transferred within said conduit(s) from said extraction vessel into said SOP-
forming tank
using valves and pumps as necessary. Said secondary recoverable volume is
retained in
said SOP-forming tank until the temperature of the liquid of said secondary
recoverable
volume is measured to be at or below said ambient temperature.
Following removal from said extraction vessel of said secondary recoverable
volume, said
insoluble residue remaining in said extraction vessel is further processed in
whatever way
desired, an obvious way being to carry said insoluble residue through the
usual pulping
process in support of subsequent production of paper and related cellulosic
products. If
disposal into the environment is opted for, an important consideration is that
said insoluble
residue is enriched in alkaline hydroxide content and therefore would be
potentially
harmful to life if it were not first neutralized and desalted by some means.
An aliphatic alcohol in liquid state of at least 95% purity, containing by
volume 5% or less
water, and pre-chilled to a temperature at least 10 0C below its flash point
is transferred
within conduit(s), using valves and pumps as necessary, from an alcohol
storage tank into
said SOP-forming tank containing said secondary recoverable volume. Suitable
species of
said aliphatic alcohol include ethanol, methanol, 2-propanol or n-butanol.
Said aliphatic
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CA 02675940 2010-12-08
alcohol is added to said secondary recoverable volume until the total volume
of liquid
contained in said SOP-forming tank is twice, within volumetric precision of
2%, that of said
secondary recoverable volume. Said total volume of liquid contained in said
SOP-forming
tank is mixed for a time, here designated as secondary mixing time, selected
from the range
1 - 30 minutes, the duration of said secondary mixing time being sufficient to
achieve
uniform mixing thus producing a 1:1 (v/ v) homogeneous mixture, here
designated as
secondary mixture, of said secondary recoverable volume and the equivalent
volume of said
aliphatic alcohol. Following elapse of said secondary mixing time, said
secondary mixture is
held static at said ambient temperature and said ambient pressure in said SOP-
forming tank
for a setting time, here designated as secondary setting time, selected from
the range 0.1 - 24
hours. During the course of said secondary setting time, a fluid suspension of
coagulated
substances containing oligosaccharides and polysaccharides, and here
designated as
secondary suspension, forms. The species of said aliphatic alcohol, the
precise duration of
said secondary mixing time and the precise duration of said secondary setting
time are,
within the stated bounds, variables which may be modified in order to optimize
the
productivity of said basic SOP process in relation to the species of raw plant
tissue and the
conditions and equipment available.
After elapse of said secondary setting time, said secondary suspension in said
SOP-forming
tank is stirred or mixed continuously for a time, here designated as secondary
stirring time,
at said ambient temperature and said ambient pressure to produce a dispersed
secondary
suspension. Said secondary stirring time is whatever length of time is
required to transfer
the entire volume of said dispersed secondary suspension generated from said
secondary
recoverable volume and the equivalent volume of added said aliphatic alcohol
out of said
SOP-forming tank, conveying it using pumps as necessary from said SOP-forming
tank at a
controlled flow rate within non-valved conduit(s) to said SOP separator
operating at said
ambient or lower temperature and said ambient or lower pressure and capable of
performing the processes of separating SOP from liquid, retaining and
accumulating said
cakes of secondary SOP, and concomitantly expelling liquid here designated as
secondary
waste solution from said SOP separator. Said process of separating SOP from
liquid,
retaining and accumulating said cakes of secondary SOP, and concomitantly
expelling said
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CA 02675940 2011-10-03
secondary waste solution requires use in said SOP separator of said SOP
filter. Said SOP
filter must be cellulose based and must not retain particles smaller than 1.0
pm.
10
Said controlled flow rate of said dispersed secondary suspension from said SOP-
forming
tank into said SOP separator is adjusted to be equal to or less than that of
the outflow rate
from said SOP separator of said secondary waste solution. Said controlled flow
rate is to
ensure that said dispersed secondary suspension within said conduit(s) between
said SOP-
forming tank and said SOP separator is maintained as nearly as possible as a
uniformly
dispersed suspension during its inflow into said SOP separator. Said secondary
waste
solution upon exiting said SOP separator is transferred within conduit(s),
using pumps and
valves as necessary, to a storage tank in support of its subsequent
distillation, said
distillation being to recover said aliphatic alcohol.
Said SOP separator has inlet(s) that may be opened or closed and outlet(s)
that may be
opened or closed to permit said dispersed secondary suspension or other liquid
to enter and
exit, respectively and, if of the centrifuge type, said SOP separator must be
able to generate
centripetal forces between 0 X g and 500 X g. The processes of SOP cake
formation from said
dispersed secondary suspension followed by¨washing, bleaching and dehydration
are
specified here as they would proceed using as said SOP separator a stainless
steel vertical
basket centrifuge and using as said SOP filter a removable cellulosic filter
bag and stainless
steel wire mesh backing against a stainless steel perforated vertical basket.
CA 02675940 2010-12-08
It will be apparent that other devices could serve as SOP separator and other
kinds of filter
and backing as SOP filter, and the intention here is not to limit innovation
in this realm of
said basic SOP process. There are many kinds of centrifuges and centrifuge
filters used in
chemical, pharmaceutical, food and textile industries which are candidates for
said SOP
separator used in said basic SOP process. Alternatively, a positive pressure
combined
filtration cake-drying system, a vacuum filtration system, a gravity-flow
filtration system, or
even a suitably modified clothes washing machine fitted with said SOP filter
could serve as
said SOP separator.
Insoluble substances within said dispersed secondary suspension are
accumulated as a cake,
here designated as a cake of secondary SOP within the bounds delimited by said
SOP filter
within said vertical basket while clear liquid, here designated as secondary
waste solution,
concomitantly passes through said SOP filter and exits said SOP separator
operating at said
ambient or lower lemperature and conditions of pressure intrinsic to said SOP
filter and said
SOP separator. During accumulation of said cake of secondary SOP within said
vertical
basket of said SOP separator, said controlled flow rate of said dispersed
secondary
suspension from said SOP-forming tank into said SOP separator is adjusted to
be equal to or
less than that of the outflow rate from said SOP separator of said secondary
waste solution.
Said controlled flow rate is to ensure that said dispersed secondary
suspension within the
conduit(s) between said SOP-forming tank and said SOP separator is maintained
as nearly
as possible as a uniformly dispersed suspension during its inflow into said
SOP separator.
Said secondary waste solution upon exiting said SOP separator is transferred
within
conduit(s), using valves and pumps and necessary, to a storage tank in support
of its
subsequent distillation, said distillation being to recover said aliphatic
alcohol. The rate at
which said cake of secondary SOP accumulates and said secondary waste solution
exits is
regulated by changing the angular velocity of said vertical basket such that
it provides a
constant centripetal force selected from within the range of 1 X g to 500 X g.
Accumulation
of said cake of secondary SOP within said vertical basket providing said
constant centripetal
force continues until the volume of said cake of secondary SOP within said SOP
filter is 50%
or less of the volumetric capacity of said vertical basket, whereupon outflow
of said
secondary dispersed suspension from said SOP-forming tank is stopped. Said
vertical
21
CA 02675940 2010-12-08
basket providing said constant centripetal force continues accumulating said
cake of
secondary SOP until the volume of said secondary dispersed suspension
remaining in said
SOP-forming tank and said conduit(s) between said SOP-forming tank and said
SOP
separator has been drained and washed from within said conduit(s) into said
SOP separator,
thus producing clean conduit(s). After draining said conduit(s) of said
secondary dispersed
suspension, said clean conduit(s) is produced by introducing into said
conduit(s) at its point
of departure from said SOP-forming tank said secondary washing solution
comprising 1:1
(v/ v) mixture of water and said aliphatic in sufficient volume to clean said
conduit(s) of said
secondary dispersed suspension, allowing said secondary washing solution to
flow into and
out of said SOP separator, using pumps as necessary. The moment said clean
conduit has
been produced, the rate of spinning of said vertical basket is decelerated to
angular velocity
equal to zero.
Said cake of secondary SOP is converted into bleached SOP here designated as
bleached
secondary SOP by bleaching said cake of secondary SOP contained within said
vertical
basket within said SOP separator for a bleaching time, here designated as
secondary
bleaching time, selected from the range 0.2 - 1.0 hour at said ambient or
lower temperature
and said ambient pressure. Immediately prior to the start of said secondary
bleaching time,
said outlet of said SOP separator is closed and bleaching solution, here
designated as
secondary bleaching solution and comprising by volume a percentage of hydrogen
peroxide
selected from the range 3 - 10%, 50% 5% by volume said aliphatic alcohol and
the balance
water, is introduced at said ambient temperature into said vertical basket in
sufficient
volume to fill said SOP separator to its operational capacity. Within said
range 3 - 10%, the
combined volume percentages of said hydrogen peroxide and said water in said
secondary
bleaching solution must add to 50% 5% of the total volume of said secondary
bleaching
solution. The precise duration of said secondary bleaching time and the
precise percentages
of said hydrogen peroxide and water within said secondary bleaching solution
are variables
which may be modified in order to optimize the efficiency and productivity of
said basic
SOP process in relation to the species of raw plant tissue and the conditions
and equipment
available.
22
CA 02675940 2010-12-08
After expiry of said secondary bleaching time, said outlet of said SOP
separator is opened
and expelling of used said secondary bleaching solution, here designated as
used secondary
bleaching solution, is begun. During the process of said expelling of said
used secondary
bleaching solution, the angular velocity of said vertical basket is
accelerated to a constant
centripetal force, selected from within the range of 1 X g to 500 X g,
continuing to expel said
used secondary bleaching solution from said SOP separator while the angular
velocity of
said vertical basket increases and thereafter for five additional minutes of
operation of said
vertical basket providing said constant centripetal force, thus achieving the
goal of
producing said bleached secondary SOP. Said used secondary bleaching solution
as
expelled from said SOP separator is conveyed within conduit(s), using valves
and pumps as
necessary, to a suitable storage tank in support of its subsequent
distillation, said distillation
being to separate and recover said aliphatic alcohol. The precise centripetal
force of said
constant centripetal force used to expel said used secondary bleaching
solution from said
SOP separator is a variable which may be modified in order to optimize the
efficiency and
productivity of said basic SOP process in relation to the species of raw plant
tissue and the
conditions and equipment available.
Said bleached secondary SOP spinning within said vertical basket providing
said constant
centripetal force is rinsed for a rinsing time selected from the range five to
thirty minutes
using a continuous spray of rinsing solution here designated as secondary
rinsing solution
and comprising 1:1 (v/v) mixture of water and said aliphatic alcohol, used
said secondary
rinsing solution here designated as used secondary rinsing solution being
expelled from said
SOP separator throughout said rinsing time and conveyed from there within
conduit(s),
using valves and pumps as necessary, to a suitable storage tafflc in support
of its subsequent
distillation, said distillation being to separate and recover said aliphatic
alcohol. Said
secondary rinsing solution has a temperature lower than said ambient
temperature, and the
flow rate of incoming said secondary rinsing solution is the same or lower
than the flow rate
of outgoing said used secondary rinsing solution. The precise duration of said
rinsing time,
the precise temperature of said secondary rinsing solution and the precise
flow rate of
incoming said secondary rinsing solution are variables which may be modified
in order to
23
CA 02675940 2010-12-08
optimize the efficiency and productivity of said basic SOP process in relation
to the species
of raw plant tissue and the conditions and equipment available.
Said bleached secondary SOP spinning within said vertical basket providing
said constant
centripetal force is converted into partially dehydrated SOP, here designated
as bleached
dehydrated secondary SOP, by treating said bleached secondary SOP with said
dehydration
alcohol. Said bleached secondary SOP spinning in said vertical basket
providing said
constant centripetal force is sprayed for five minutes with said dehydration
alcohol pre-
chilled to a temperature at least 10 0C below the flash point of said
dehydration alcohol and,
at the moment of spraying, having a temperature lower than said flash point.
The flow rate
of incoming said dehydration alcohol is the same or lower than the flow rate
of outgoing
said dehydration alcohol that is concomitantly expelled as said used
dehydration alcohol
from said SOP separator. The precise temperature of said dehydration alcohol
and the
precise flow rate of incoming said dehydration alcohol are variables which may
be modified
in order to optimize the efficiency and productivity of said basic SOP process
in relation to
the species of raw plant tissue and the conditions and equipment available.
Following
completion of said spraying, said bleached secondary SOP is spun in said
vertical basket
providing said constant centripetal force for five additional minutes while
continuing to
expel said used dehydration alcohol from said SOP separator and from there via
conduit(s),
using valves and pumps as necessary, to a suitable storage tank in support of
its subsequent
distillation, said distillation being to separate and recover said aliphatic
alcohol. Said
vertical basket is then decelerated to zero angular velocity, and said
bleached dehydrated
secondary SOP and said SOP filter are removed from said SOP separator for
storage or
further processing as desired.
Said bleaching of said cake of secondary SOP may be useful in relation to the
intended end
product but is non-essential for SOP production per se. When it is elected not
to do said
bleaching, said cake of secondary SOP contained in said SOP filter within said
vertical
basket of said SOP separator is converted directly into washed secondary SOP
by washing
said cake of secondary SOP cake at said ambient or lower temperature and said
ambient or
lower pressure with washing solution, here designated as secondary washing
solution and
24
CA 02675940 2010-12-08
comprising 1:1 (v/v) mixture of water and said aliphatic alcohol for a
secondary washing
time selected from the range 0.2 - 1.0 hour. The precise temperature of said
ambient or
lower temperature, the precise pressure of said ambient or lower pressure, and
the precise
duration of said secondary washing time are variables which may be modified in
order to
optimize the efficiency and productivity of said basic SOP process in relation
to the species
of raw plant tissue and the conditions and equipment available. To initiate
said washing,
the outflow valve of said SOP separator is closed, and said secondary washing
solution at
said ambient or lower temperature is introduced into said SOP separator in
sufficient
volume to fill said SOP separator to its operational capacity. Once filled to
said operational
capacity, the outlet of said SOP separator is opened, and expelling of used
said secondary
washing solution, here designated as used secondary washing solution, is
begun. After start
of said expelling of said used secondary washing solution, the angular
velocity of said
vertical basket is accelerated until said vertical basket provides a constant
centripetal force
selected from within the range of 1 X g to 500 X g, continuing to expel said
used secondary
washing solution throughout the acceleration period and for five additional
minutes after
said constant centripetal force has been achieved. The precise said constant
centripetal force
used after said start of said expelling of said used secondary washing
solution may be
modified in order to optimize the productivity of said basic SOP process in
relation to the
species of raw plant tissue and the conditions and equipment available.
Following elapse of said five additional minutes, said cake of secondary SOP
in said vertical
basket providing said constant centripetal force is subjected for the
remainder of said
secondary washing time to a continuous spray of said secondary washing
solution to
generate washed secondary SOP and used secondary washing solution, expelling
throughout that time from said SOP separator said used secondary washing
solution. Said
used secondary washing solution is conveyed after said expelling within
conduit(s), using
valves and pumps as necessary, to a suitable storage tank in support of its
subsequent
distillation, said distillation being to separate and recover said aliphatic
alcohol.
Said washed secondary SOP is converted into partially dehydrated secondary
SOP, here
designated as dehydrated secondary SOP, by spraying said washed secondary SOP
in said
CA 02675940 2010-12-08
vertical basket providing said constant centripetal force for five minutes
with said
dehydration alcohol pre-chilled to a temperature at least 10 0C below the
flash point of said
dehydration alcohol. The flow rate of incoming said dehydration alcohol is the
same or
lower than the flow rate of outgoing said used dehydration alcohol that is
concomitantly
expelled as said used dehydration alcohol from said SOP separator. The precise
temperature of said dehydration alcohol and the precise flow rate of incoming
said
dehydration alcohol are variables which may be modified in order to optimize
the efficiency
and productivity of said basic SOP process in relation to the species of raw
plant tissue and
the conditions and equipment available. Following completion of said spraying,
said
washed secondary SOP is spun in said vertical basket providing said constant
centripetal
force for five additional minutes while continuing to expel said used
dehydration alcohol
from said SOP separator within conduit(s), using valves and pumps as
necessary, to a
suitable storage tank in support of its subsequent distillation, said
distillation being to
separate and recover said aliphatic alcohol. Said vertical basket is then
decelerated to zero
angular velocity, and said dehydrated secondary SOP and said SOP filter are
removed from
said SOP separator for storage or further processing as desired.
Following transfer of said entire volume of said dispersed secondary
suspension from said
SOP-forming tank to said SOP separator during production of said cakes of
secondary SOP,
the walls of said SOP-forming tank are washed to produce clean SOP-forming
tank. Said
clean SOP-forming tank is produced by washing the walls of said SOP-forming
tank with
said secondary washing solution at said ambient or lower temperature and of
volume no
less than three times the volume contained by those said non-valved conduit(s)
used to
transfer said dispersed secondary suspension from said SOP-forming tank to
said SOP
separator. While washing said walls of said SOP-forming tank, said secondary
washing
solution is expelled from said SOP-forming tank via said outlet ports of said
SOP-forming
tank into said non-valved conduit(s) and transferred through said non-valved
conduit(s) to
and through said inlet(s) into said SOP separator at a flow rate regulated to
match the rate of
removal of liquids from said outlet(s), using pumps as necessary. After said
washing of said
walls of said SOP-forming tank with said secondary washing solution and
expelling of said
secondary washing solution from said SOP-forming tank, cleaning of said non-
valved
26
CA 02675940 2010-12-08
conduit(s) between said SOP-forming tank and said SOP separator is done. Said
cleaning is
accomplished by introducing into said SOP-forming tank and said outlet ports
of said SOP-
forming tank said secondary washing solution at said ambient or lower
temperature and of
volume no less than three times the volume contained by those said non-valved
conduit(s)
used to transfer said dispersed secondary suspension from said SOP-forming
tank to said
SOP separator at a flow rate regulated to match the rate of removal of liquids
from said
outlet(s), using pumps as necessary.
After completion of said cleaning, said non-valved conduit(s) between said SOP-
forming
tank and said SOP separator is disconnected from said inlet(s) leading into
said SOP
separator, and flushing of said SOP-forming tank and said non-valved
conduit(s) is done.
Said flushing is accomplished by introducing into said SOP-forming tank liquid
water
having a temperature below the boiling point for outflow of said liquid water
through said
outlet ports of said SOP-forming tank hence through said non-valved
conduit(s). Said
flushing is continued until clear water flows freely from the disconnected
end(s) of said non-
valved conduit(s).
Cakes of SOP, whether of primary or secondary designation, bleached or
unbleached,
hydrated or partially dehydrated, as produced in said basic SOP process are
miscible in
water upon stirring. A
clear solution of water miscible oligosaccharides and
polysaccharides, here designated as MOP, is produced by weighing a mass of
said SOP and
adding to said mass a volume in litres of water equaling at least twice the
mass in kilograms
of said SOP, followed by stirring the mixture at said ambient pressure and a
temperature
between 0 oC and 100 oC until a clear solution is obtained. The precise
temperature of said
stirring to produce said MOP is a variable which may be modified in order to
optimize the
efficiency and productivity of the process in relation to the species of raw
plant tissue and
the conditions and equipment available. Said MOP is a convenient way to
transport and
further refine SOP.
Said distillation is specified as part of the overall said basic SOP process,
and said distillation
is done in a distillation apparatus in order to recover and, if so desired, to
recycle said
aliphatic alcohol. Said distillation is not essential for production of SOP
using said basic
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CA 02675940 2010-12-08
SOP process, but said distillation serves to prevent the environmental
contamination which
might otherwise occur, and said distillation also presents the opportunity for
the aqueous
residue remaining after said distillation also to be used again. Recovery by
volume of said
aliphatic alcohol during said distillation is in the range of 85 - 95% of the
volumes of said
aliphatic alcohol introduced into said SOP forming tank to produce said
primary suspension
and said secondary suspension. If said distillation employs boiling at ambient
pressure at or
near the boiling temperature of said aliphatic alcohol, said aliphatic alcohol
is recovered in
marginally higher yield than if said distillation employs vacuum distillation
at a
temperature below the ambient boiling temperature.
Said aqueous residue remaining after said distillation can be transferred via
conduit(s),
using pumps and valves as necessary, from said distillation apparatus to fill
an alkali
storage tank to a known volume. Said alkali storage tank must be capable of
stirring and/or
mixing its contents at said ambient temperature and pressure. Said aqueous
residue
transferred from said distillation apparatus into said alkali storage tank is
titrated for its
alkaline hydroxide content followed by addition to said aqueous residue
sufficient amount
of said alkaline hydroxide to produce alkaline soaking solution that fulfils
the specified
requirement of said known concentration of said primary soaking solution or
said secondary
soaking solution. From said alkali storage tank, said alkaline soaking
solution is transferred
to said extraction vessel to achieve a said primary soak or a said secondary
soak of another
batch of said pieces of raw plant tissue of dimensions up to or less than 10
mm in thickness,
10 mm in width and 50 mm in length. In this way, said aqueous residue can be
recycled
through said basic SOP process.
Following repeated recycling of said aqueous residue in support of the
production of
successive batches of SOP using said basic SOP process, an insoluble
precipitate forms in
said aqueous residue within said distillation apparatus during or after said
distillation. Said
insoluble precipitate is formed from substances which were extracted from said
pieces of
raw plant tissue and/or from said insoluble residue of said pieces of raw
plant tissue during
said primary soak and/or said secondary soak, respectively. Said insoluble
precipitate
comprises chemical substances potentially of high economic value and,
following removal
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CA 02675940 2010-12-08
from said distillation apparatus of the clear liquid component of said aqueous
residue, said
insoluble precipitate remaining in said distillation apparatus may be
recovered either by
physical means or by dissolving said insoluble precipitate in an appropriate
solvent and
removing that solution, simultaneously cleaning said distillation unit. Said
clear liquid
component of said aqueous residue is transferred via conduit(s), using pumps
and valves as
necessary, from said distillation apparatus to fill to a known volume said
alkali storage tank
capable of stirring and/or mixing its contents at ambient temperature and
pressure. Said
clear liquid component of said aqueous residue transferred from said
distillation apparatus
into said alkali storage tank is titrated for its alkaline hydroxide content
followed by
addition to said aqueous residue sufficient amount of said alkaline hydroxide
to produce
alkaline soaking solution that fulfils the specified requirement of said known
concentration
of said primary soaking solution or said secondary soaking solution. From said
alkali
storage tank, said alkaline soaking solution is transferred to said extraction
vessel to achieve
a said primary soak or a said secondary soak of another batch of said pieces
of raw plant
tissue of dimensions up to or less than 10 mm in thickness, 10 mm in width and
50 mm in
length.
If disposal into the environment rather than recycling of said aqueous residue
is opted for, it
deserves emphasis that said aqueous residue is enriched in alkaline hydroxide
content and
therefore is potentially harmful to life if not first neutralized and desalted
by some means,
for example, by addition of acid to lower the pH and enable removal of the
high salt
concentration.
A number of variables potentially affecting SOP yield and/or cost are listed
below in
relation to production of said number one bleached dehydrated SOP, only, but
this listing
also serves to reveal the broad methodological versatility available to said
basic SOP process
in relation to production of SOP in general. A non-comprehensive list of said
variables
includes the following:
1) said plant species which is processed;
2) anatomical and chemical composition including water content of said raw
pieces of
plant tissue processed;
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CA 02675940 2010-12-08
3) kind and size of said extraction vessel used;
4) alkaline hydroxide metal(s), viz., sodium potassium, lithium, selected for
use in said
primary soaking solution;
5) said known concentration of said alkaline hydroxide used in said primary
soaking
solution;
6) duration of said primary soaking time in said extraction vessel;
7) temperature of said primary soaking solution in said extraction vessel;
8) method used to displace and transfer said primary soaking solution from
said
extraction vessel to said SOP-forming tank;
9) respecting said conduit(s) between said extraction vessel and said SOP-
forming tank,
said conduit(s) between said SOP-forming tank and said SOP separator, and said
conduit(s) between said SOP separator and tanks receiving solutions expelled
from
said SOP separator, all must be compatible with said alkaline hydroxide and
said
aliphatic alcohol and, therefore, it is recommended that all be of inert
plastic;
however, shape, wall thickness, and dimensions of said conduit(s) are not
specified
here;
10) non-specified features of said SOP forming tank;
11) kind of said aliphatic alcohol added to said SOP forming tank to produce
said
primary suspension;
12) duration of said mixing time in said SOP forming tank to produce said
primary
mixture;
13) method and intensity of mixing to achieve said primary mixture in said SOP
forming
tank;
14) duration of said setting time to produce said primary suspension;
15) nature of said SOP separator and said SOP filter;
16) physical environment setpoints used during separation of SOP batch number
one
from the 1:1 (v/v) mixture of alkaline soaking solution and aliphatic alcohol;
17) duration of washing, bleaching, rinsing and dehydrating the SOP cake.
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Example
Data arising from application of said basic SOP process to pieces of wood from
Betula
populifolia are presented herewith in Figure 1 and Tables 1-11, and data on
SOP yields from
tissues of a number of additional plant species using said basic SOP process
are also
presented in Tables 11 and 12. However, said data are not to specify that said
basic SOP
process as stated for B. populifolia and said additional plant species must be
rigidly adhered
to for either those or other plant species. Using said basic SOP process, some
quantity of
SOP evidently can be obtained from any tissue of any plant species, and the
methodological
latitude within said basic SOP process invites modifications in order to
increase SOP yield
and reduce costs.
The chemistry of SOP from Betula populifolia wood was investigated in some
depth, by
dialysis followed by sulfuric acid hydrolysis of the SOP followed by barium
carbonate
neutralization, drying, trimethylsilylation and analysis by combined gas
chromatography -
mass spectroscopy (GC/ MS). Dialysis through cellulose acetate of different
molecular-
weight cutoffs established that B. populifolia SOP comprises a small fraction
of short-chain
oligosaccharides as well as larger polysaccharides, the major fraction being
above 10,000
Daltons. GC/MS analysis of hydrolyzed, trimethylsilylated SOP revealed that B.
populifolia
SOP contains equal amounts of D-xylose and 4-mefftylglucuronic acid as its
dominant
building blocks. Those two compounds are well known constituents of
Magnoliophyta
hemicelluloses, and thus said basic SOP process is a simple and rapid method
to mass
produce those two compounds. However, considerable research remains to be done
in
order to understand the chemistry of SOP as it may vary among plant species.
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Data on SOP production from wood of Betula populifolia using the basic SOP
process.
Figure 1. Percentage yield of SOP from dry, raw wood of Betula populifolia as
a function of
temperature and NaOH molarity.
30
Linear twater (control))
4.
- - Linear OM Na011)
SOP
20 -
yield ¨ Poly. t2.5M NaOH)
(A)
15 - - - - Poly. (5M Na011)
10.e
= === = µ*.
=
= = 111
5= , = '
====
-r0
= ................................................. 4
4 25 50 80 100
Extraction temperature ( C)
Table 1. Dehydrated SOP yields (% of dry, raw wood weight) after extracting
dry, raw
Betula populifolia wood particles for different time periods with 1 M NaOH at
25 oC; standard
deviations (s.d.) are for 3 replicate investigations.
Time (hours) % SOPs.d.
0.1 <0.1 0.0
1 7.6 0.2
2 7.5 0.4
3 8.3 0.4
4 7.6 0.3
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Table 2. Dehydrated SOP yields (% of dry, raw wood weight) after extracting
dry, raw
Betula populifolia wood particles for 1 hour at 50 0C at different NaOH
molarities; standard
deviations (s.d.) are for 3 replicate investigations.
NaOH
molarity % SOPs.d.
water only 0.3 0.0
1.0 4.6 0.1
2.5 14.7 0.3
5.0 11.2 0.6
10.0 13.2 0.3
Table 3. Dehydrated SOP yields (% of dry, raw wood weight) after extracting
different sizes
of dry, raw Betula populifolia wood particles once or twice for different time
periods with 2.5
M NaOH at 50 0C; standard deviations (s.d.) are for 3 replicate
investigations.
Maximum particle surface area
dimension (mm) (mm2/ gram) % SOPs.d.
3.5 4160 16.0 0.5
130 1600 5.8 0.1
136 1280 5.8 0.2
176 1120 4.6 0.6
Table 4. Dehydrated SOP yields (% of dry, raw wood weight) after extracting
dry, raw
Betula populifolia wood particles once or twice for different time periods
with 2.5 M NaOH at
50 oC; standard deviations (s.d.) are for 3 replicate investigations.
No. of times
extracted Time (hours) % SOP s.d.
once 1 12.8 0.4
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CA 02675940 2010-12-08
twice 1, 1 17.3 0.3
twice 0.1, 1 16.3 0.5
once 0.165 9.9 0.4
once 1.165 13.0 0.6
Table 5. Dehydrated SOP yields (% of dry, raw wood weight) as influenced by
the aliphatic
alcohol used, after extracting dry, raw Betula populifolia wood partides with
2.5 M NaOH for
one hour at 50 0C; and adding an equal volume of an aliphatic alcohol to
generate a SOP
suspension; standard deviations (s.d.) are for 3 replicate investigations.
Aliphatic alcohol % SOPs.d.
ethanol 15.3 0.3
methanol 11.5 0.4
2-propanol 6.7 0.3
n-butanol 5.2 0.1
Table 6. Dehydrated SOP yields (% of dry, raw wood weight) after extracting
dry, raw
Betula populifolia wood particles with 1.0 M NaOH or 2.5 M NaOH at 50 0C and
adding the
indicated volume of ethanol to generate a SOP suspension; standard deviations
(s.d.) are for
3 replicate investigations.
1.0 M NaOH 2.5 M NaOH
% (v/v) ethanol % SOPs.d. % SOP s.d.
50% 6.0 0.2 23.0 1.4
67% 7.4 0.3 21.5 1.1
Table 7. Dehydrated SOP yields (% of dry, raw wood weight) after extracting
dry, raw
Betula populifolia wood partides with three kinds of alkali at 1.0 M or 2.5 M
concentrations
for 1 hour at 50 0C; standard deviations (s.d.) are based on 3 replicate
investigations.
Alkali % SOP (1.0 M) s.d. % SOP (2.5 M) s.d.
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CA 02675940 2010-12-08
NaOH 4.3 0.3 15.9 0.7
KOH 4.9 0.0 13.8 0.5
LiOH 9.1 0.6 12.1 0.2
Table 8. Yields (% of weight of dry, raw Betula populifolia wood partides) of
unbleached and
bleached (3% H202 for 10 minutes at ambient temperature) dehydrated SOP
retained by a
cellulosic filter following centrifugation at 500 X g; standard deviations
(s.d.) are for 3
replicate investigations.
Suspension % SOPs.d.
SOP in 50% 14.9 0.8
ethanol, 2.5 M NaOH
SOP in 3% H202, 50% 8.8 1.0
ethanol, 2.5 M NaOH
Table 9. Weight change of dehydrated SOP (% of the weight of dehydrated Betula
populifolia
raw SOP based on the yield provided using 50% ethanol) in relation to
incremental increases
in ethanol concentration during centrifugation, always in the presence of 2.5
M NaOH;
standard deviations (s.d.) are for 3 replicate investigations.
% ethanol weight % s.d.
60 97.6 0.1
70 86.1 0.3
80 90.5 0.2
90 96.2 0.2
95 95.9 0.4
Table 10. SOP recovery as a function of ethanol concentration in water in
relation to the
process of stepwise ethanolic dehydration of SOP
CA 02675940 2010-12-08
Ethanol (% v/v) SOP recovery (%)
50 100
60 94
70 85
80 98
90 100
95 97
Table 11. Bleached (3% H202 with 47% ethanol and 50% water for 10 minutes at
ambient
temperature) and unbleached dehydrated SOP yields (% of weight of dry, raw
wood
particles) from woods of several tree species; standard deviations (s.d.) are
for 3 replicate
investigations.
Tree species unbleached SOP (%) s.d. bleached SOP (%)
s.d.
Betula populifolia 12.5 0.7 9.0 0.3
Betula alleghaniensis 10.4 0.0 9.4 0.3
Acer rubrum 7.2 0.6 6.4 0.1
Populus tremuloides 9.5 0.2 7.6 0.1
Table 12. Average dehydrated SOP yields (% of dry, raw weight based on three
replicate
preparations) found for various plant species are shown beside each in
parentheses. Tissues
were extracted with 2.5 M NaOH for 1 hour at 50 0C followed by SOP
precipitation using
50% (v/v) ethanol.
Woods from tree species:
Acacia koa (15.7), Acer saccharum (6.0), Acer saccharinum (10.5), Araucaria
heterophylla (1.2),
Betula lutea (6.2), Betula populifolia (22.7), Canja pallida (5.6), Corylus
avellana (3.8), Dalbergia
latifolia (3.1), Diospyros melanoxylon (3.8), Eucalyptus camaldulensis (4.8),
Eucalyptus deanii (5.3),
Eucalyptus globulus (14.6), Fraxinus americana (5.0), Guaiacum officinale
(3.1), Juglans cinerea
(19.2), Juglans nigra, Khaya ivorensis (10.2), Liquidambar styraciflua (8.0),
Ochroma pyramidales
(14.1), Paulownia tomentosa (12.0), Platanus occidentalis (12.6), Podocarpus
guatmalensis (1.7),
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Prunus serotina (15.8), Pterocarpus indicus (3.2), Quercus alba (9.4), Quercus
robur (16.1), Quercus
rubra (8.0), Salix fragilis (10.6), Swietenia macrophylla (15.0), Tectona
grandis (2.6), Terminalia
superb (4.6), Terminalia tomentosa (3.9), Turraean thus africana (1.8), Ulmus
americana(4.9).
Stems, leaves and reproductive structures: Achillea millefolium (20.6),
Bambusa oldhamii
(40.2), Gossypium hirsutum (0.2), Hypericum perforatum (28.8), Melilotus alba
(16.8), Phalaris
arundinacea (39.3), Phleum pretense (31.6), Solidago juncea (21.7).
37
