Note: Descriptions are shown in the official language in which they were submitted.
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INSOLUBLY BOUND PARTICULATE PRODUCTS
BACKGROUND OF THE INVENTION
This invention relates to a bio-based binding agent that is particularly
effective when used in conjunction with a process disclosed herein for making
impermeable agglomeratges from finely divided minerals, such as coal, and for
making insoluble composite materials from particulated lignocellulosics.
Many finely divided but otherwise useful materials are neglected or
abandoned merely because they contain unwanted moistures; clearly, a low cost
means for bonding such materials into durable products with a permanently
reduced
moisture content would enhance both their utility and value.
Providing such a means is a principal aspect of this invention.
Earlier, attempts were made to adapt techniques disclosed in Applicant's US
Patent Ns 5,371,194 "Biomass Derived Thermoset Resin" & N 5,582,682 "Process
for Making Cellulosic Composites" to the production of synthetic solid fuel
from
fines created during the mining of Wyodak coal in the western United States.
Although acceptable quality syn-fuel products were made, the cost of energy
required
to remove all entrained water and to polymerize the binder was prohibitive.
These
results underscored the need for a less energy-intensive, and altogether
cheaper
method of making weather-resistant products from particulate materials -- a
need now
satisfied by the technology disclosed herein.
An exceptionally promising embodiment of this invention provides a long-
sought alternative to coal mining's most waste-intensive practice - the
improvident
discard of huge quantities of moisture-laden fine coal. In particular, this
synthetic-
fiiel-making process has the capacity to open a new and profitable outlet for
this
energy-rich-debris - which at present creates environmental tensions and
financial
burdens throughout the coal industry.
The novelty and economic merit of this new syn-fuel-making process, and the
bio-based composition on which it relies, are unequivocally established by
eliminating the need for the thermal energy invariably required by the prior
art to
dewater and dry coal fines, and to cure binders. The ability to dewater, shape
and
bond a variety of particulate feedstocks in a single continuous operation -
without the
input of thermal energy - is a distinguishing feature of processes employing
this new
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bio-based composition. Coalescing, as used herein, means to quantify, shape,
compress and express essentially all free water from a mixture of particulate,
a wet-
tack lubricant solution and as water-insoluble binding agent. When a
chemically-
inert particulate is agglomerated, coalescing may include both direct and
indirect
transfer of heat generated by compressive friction to the incipient
agglomerate.
Essential to the dewatering method utilized in this invention is the presence
on particulate surfaces of a substance, defined herein as a wet-tack
lubricant, in very
dilute solution. The preferred wet-tack lubricant is polyethylene oxide (PEO),
a non-
ironic water-soluble resin particularized by Union Carbide Corporation (UCI),
Danbury, CT 06817, in brochure UC-876 5/95-5M. Relevant properties of PEO
mentioned in the brochure include: "Lubricity, Friction Reduction, Water
Thickening, Wet-Tack, and Shear-Thinning, and a high affinity for coal-fines,
lignin
and paper fines". PEO is known to flocculate lignocelluloisics but not
hydropohobic
coal-fines, and it is hydrophilic but not a surfactant. While it is a
relatively new
chemical, the use of PEO in coal and paper processing has become extensive.
US patent N2 4,322,219 of Burns discloses a process for removing moisture
by contacting coal-either run-of-mine or pipeline slurry coal - with a dilute
aqueous
solution of PEO and allowing the moisture to evaporate; alcohol may be added
to
accelerate evaporation. The use of PEO solutions to "...avoid the tendency of
high-
moisture low-rank coal to slack or degrade in size..." is mentioned, however,
no
mention is made of small particles, or fines, and no suggestion that PEO could
be
used to facilitate the forcible expression of water from coal, or coal fines,
or that de-
watered coal, or coal-fines, could be agglomeratged into a fuel product - with
or
without a binder.
The use of hydrophilic PEO in the process of present invention distinguishes
it from US patent Ns 5,670,056 of Yoon et al, which utilizes a hydrophobic
reagent
- preferably, mono unsaturated fatty esters or polysiloxane polymers - to aid
mechanical means for dewatering coal-fines'. No treatment beyond the
dewatering of
fine materials, such as agglomeration or bonding, is mentioned or suggested.
US Patent N2 5,658,357 of Liu et al, "Process For Forming Coal Compact
Without A Binder", uses the surface tension of water and the absence of air-
bubbles
to furnish "...a binding effect which holds the carboniferous particles
together and
imparts mechanical strength in the compact..." If the surface-tension-
producing
water is removed from such a compact, disintegration quickly follows. Aside
from
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reducing coal-log drag in a pipe line, the sole purpose of using a very dilute
solution
of PEO is reduction of the zeta potential to lessen electrostatis repulsion
between
particles in a coal slurry. In the present invention, the hydrophilicity,
lubricity,
thickening, shear-thinning, and fines affinity of PEO combine to facilitate
particulate
dewatering, densification and, unexpectedly, bonding during coalition.
Except for pellets made on a disc pelletizer, agglomerates made from mineral
particulate by the process of the present invention have no need for the
interim
strength provided by PEO or supplemental heat; they are inherently insoluble
and
impermeable and - because they have been subjected to frictional heat of
compressive coalition - strong and durable. But no appreciable heat is
produced
during disc pelletizing; therefore, although agglomerates made on these
machines are
impermeable and insoluble, supplemental heat is needed to obtain a peak
strength
product. As used herein, the terms insoluble and impermeable refer to the
behavior
of a product or substance with respect to water.
White's US Patent N2 4,865,691 exploits a unique property of normally
insoluble but water swellable polyvinyl (PVOH) particles: Swollen particles
are
dispersed in a dilute aqueous suspension of cellulosic fiber which, as excess
water is
drained, acts as a sieve retaining the swollen PVOH particles within the web.
When
heated, the entrapped swollen residual free water diffuse into the web and, on
cooling, solidify into a paper-reinforcing binder.
In US Patents NQ 5,498,314, 5,328,56.7, and 5,800,675, Kinsley describes
newer domestic grades of PVOH powder available from Air Products and
Chemicals,
Inc. (APCI) of Allentown, PA, and specifics Airvol 125SF, 165SF, 350SF, 107SF,
and 325SF as, grades that will allow the use of larger quantities of PVOH
without
undesirable side effects. None of the four aforementioned patents specify or
suggest
the use of PVOH in an unswollen state, or for a purpose other than paper-
making.
Because PVOH is employed in a dissolved state as a coal-fines binder in the
processes described in US patents N2 4,787,913 of Goleczka, et al, and N2s
4,586,936 and 4,863,485 of Schaffer, et al, they are easily distinguished from
the
present invention, wherein PVOH is used in an undissolved state. Neither
swelling
or dissolving PVOH powder is necessary to the present invention.
The `cook-out' (dissolution) temperature of PVOH is specified by the
manufacturer, APCI, as below 205 F (93 C) for all grades. In addition to the
bio-
based composition of the present invention and suitable grades of PVOH listed
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above, there are numerous water-insoluble binding agents, e.g., phenolic,
acrylic,
epoxy, thermosetting, or thermoplastic resins that melt or become temporarily
soluble
within the coalition temperature range (150-220 F) and would, therefore, be
technically suitable for this duty. Without exception, however, such plastics
have
been found to be uneconomic.
Little if any frictional heat is created by the apparatus during coalition of
lignocellulosic particulate to melt and disperse the PVOH powder. Product
integrity
and structural strength on an interim basis - without which the ostensibly-dry
composite could not tolerate handling and shaping - must therefore be provided
by
PEO. For durability and peak strength, the ostensibly-dry composite material
must
be heated to melt and diffuse the PVOH, preferably while contained in 'a mold
or
press.
Coalesced composite material, with interim strength provided by PEO, may
also be processed e.g., molded, rolled, and shaped, and later subjected to
heat
sufficient to melt and disperse the binding agent, and dry the product. Like
many
other plasticizers known in the art, a small amount of PVOH will enhance
composite
tensile strength and flexibility. Likewise, small amounts of various lipids,
such as
paraffin, paraffin emulsions, and stearates and steric acids, will enhance
composite
hydrophobicity.
Any substantially water-insoluble PVOH powder hydrolyzed to a super, fully,
or intermediate, extent is deemed suitable for use in this invention, with the
higher
viscosities (22-72 cps) preferred. The utility of undissolved PVOH powder is
not
mentioned in APCI's brochure, nor is it disclosed in any other prior art. The
phrase
"substantially water-insoluble" means a substance that will not dissolve
appreciably
in water at room temperature, i.e., less that 25% w/w will dissolve in 30
minutes.
The use of soluble protein is old in the art of maker paper coatings and
adhesives; the process of Krinski, et al, disclosed in US Patent Ns 5,766,331,
for
making a pigment binder exemplifies such use. In this process, a cation
binding
agent is added to inhibit formation of the insoluble gel created by addition
of calcium
oxide, or hydroxide, to a protein solution. This gel - termed herein a bio-
based
binding agent - is a basic and necessary element of the present invention,
from which
Krinski, et al. `331 is clearly distinguished by its teaching of the
inhibition of gel
formation - a contrary instruction.
In US Patent N2 5,543,164 of Krochta, et al, a method for making edible
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protein-based insoluble film and coating for foods is described. The present
invention is readily differentiated from the process of Krochta et al `164, in
which: A
solution of denatured protein is applied to the exterior of a food item or
made into a
food wrapping film - rather than incorporated as a necessary reagent in the
composition of an industrial product; and, all means for denaturation,
including heat,
5 chemical or enzymatic treatment, may be employed - rather than the addition
of
calcium oxide or hydroxide, the only means found effective in the present
invention.
It is believed the alkaline ambiance created in products of the present
invention by a
relatively large amount of such a calcium compound - in addition to effecting
the
irreversible denaturation, of the protein solution and reducing SOx emissions
during
coal combustion - prevents the growth of micro-organisms that would otherwise
eventually cause product deterioration.
Inasmuch as the binding agent composition disclosed herein stems from
chemistry never previously used to create a particulate binding agent, it is
easily
distinguished from compositions of the prior art. Specifically, in a mixture
of
particulate with only a small amount of protein, alkali denaturation
transforms the
protein in situ into an insoluble gelatinous material - which during
coalition, bonds
the particulate and forms a moisture barrier - thereby yielding an insoluble
and
impermeable agglomerate. Impermeability - which is vital to the ability of sym-
fuel
to regain a high BTU level and survive all-weather storage and transport - is
verified
with a simple water-soak test: No weight gain is observed after an agglomerate
made
by the process of this invention has been immersed in water for 24 hours.
BRIEF SUMMARY OF THE INVENTION
The process of this invention is based on the discovery that a dewatered
product with insoluble inter-particle bonds 'can be obtained when an alkali,
such as
lime, is admixed with a mixture of moist PEO-treated particulate and a soluble
protein, and the resulting admixture is coalesced. As a result of protein
denaturation,
a gelatinous insoluble substance - which acts as a binding agent and a
permanent
sealant - is formed in situ in the coalesced product. Following PEO-
facilitated
dewatering at the outset of particulate coalition, this binding agent provides
limited
product integrity and strength. If the coalesced particulate is an inert
mineral, such as
coal fines, the frictional heat that accompanies compressive coalition
evaporates
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residual moisture from the agglomerate making it stronger and more
durable - in addition to being insoluble and impermeable.
Use of this procedure with lignocellulosic particulate yields an
analogous product; however, because only a negligible amount of frictional
heat is
generated during cellulosic coalition, supplemental heat is required to obtain
a
substantially dry composite. Moreover, because the binding agent yields an
insoluble
but not impermeable composite, moisture can be re-absorbed into the
lumens and pores of lignocellulosic - unless such penetration is precluded by
the
addition of a hydrophobizing ingredient to the feedstock mixture, or
application of a
water-repellant coating to the composite product.
In one process aspect, the invention relates to a process employing a
mixture of a binding agent and an aqueous solution of a polyethylene oxide wet-
tack
lubricant having a molecular weight greater than about 200,000 to manufacture
an
insoluble product from particulate comprising: admixing said particulate with
said
mixture to obtain free-water containing binding agent, lubricant and
particulate
admixture; coalescing said admixture to manufacture said product.
In a further process aspect, the invention relates to a manufacturing
process employing a mixture of a binding agent, an aqueous solution of a
polyethylene oxide wet-tack lubricant and coal fines to manufacture an
insoluble
synthetic fuel from input feed coal fines, said process including a source of
input feed
coal fines, a conveyer and heat exchanger, a screening means, a mixer, a
source of
binding agent and wet-tack lubricant, and a coalition machine, said
manufacturing
process comprising the steps of: feeding an initial mixture of said binding
agent,
wet-tack lubricant and coal fines through said coalition machine which
provides heat
from compressive friction to evaporate residual water from said mixture and
input
coal fines and to deliver manufactured compressed heated insoluble synthetic
fuel to
said conveying and heat exchanger; then passing said heated insoluble
synthetic fuel
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and input feed coal fines along said conveyor and heat exchanger that conveys
said
input feed of coal fines and said heated insoluble synthetic fuel to said
screening
means; transferring heat from said heated insoluble synthetic fuel to said
input
coal fines along said conveyor and heat exchanger to obtain pre-heated feed
coal fines at said screening means; separating said pre-heated coal fines and
said
insoluble synthetic fuel and dispensing said manufactured insoluble synthetic
fuel at
said screening means after transferring heat to said conveyed feed coal fines
to
obtain pre-heated coal fines; admixing said separated pre-heated fines with a
mixture
of said binding agent and wet-tack lubricant to obtain a free-water-containing
binding agent, wet-tack lubricant and pre-heated coal fines admixture for feed
to said
coalition machine; coalescing said admixture in said coalition machine to
manufacture said heated insoluble synthetic fuel for transferring heat to said
input
coal fines to produce said pre-heated coal fines; and repeating said passing,
transferring heat, dispensing, admixing, and coalescing steps to continue
manufacture of said insoluble synthetic fuel.
In a still further process aspect, the invention relates to a single step
process for employing a mixture of a binding agent and an aqueous solution of
a
wet-tack lubricant to manufacture an insoluble product from particulate,
wherein an
admixture of said particulate with said mixture will yield said product when
said
admixture is subjected to said process step, which step comprises coalescing
said
admixture.
In yet a further process aspect, the invention relates to a process of
employing a mixture of a binding agent and an aqueous solution of a
polyethylene oxide wet-tack lubricant to manufacture an insoluble and
impermeable
product from a finely divided and chemically-inert mineral, comprising:
admixing said
mineral with said mixture to obtain a free-water-containing binding agent,
lubricant and mineral particulate admixture; and coalescing said admixture to
manufacture said product.
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In another process aspect, the invention relates to a process employing
a mixture of a particulate, a water insoluble binding agent and an aqueous
solution of
a wet-tack lubricant for facilitating dewatering residual water within said
particulate,
said wet-tack lubricant having a molecular weight of greater than 200,000 to
manufacture an insoluble product from said particulate comprising: admixing
said
particulate with said binding agent and said aqueous solution of wet-tack
lubricant to
obtain a free-water containing binding agent, lubricant and particulate
admixture;
coalescing said admixture to facilitate dewatering residual water within said
particulate and to bind said particulate to manufacture said insoluble
product.
In one product aspect, the invention relates to a mixture comprised of a
binding agent and an aqueous solution of a wet-tack lubricant.
In a further product aspect, the invention relates to an admixture,
comprising finely divided and chemically-inert particulate admixed with a
mixture of a
binding agent and an aqueous solution of a polyethylene oxide wet-tack
lubricant,
that will, when coalesced, yield an insoluble product.
DESCRIPTION OF THE DRAWING
The drawing, titled Fig. 2 Schematic - Sym-Fuel Manufacture, is a
representative arrangement of equipment for making syn-fuel from coal fines
and
recovering and utilizing a portion of the fractional heat generated during the
coalition
of finely divided minerals. The basic functions of the equipment shown in the
drawing
and their method of cooperation are as follows:
= A hopper to feed minerals fines = 1 cm x 0 at a measured rate to a
conveyor;
= A conveyor to transport the fines and hot coalesced product to a
heat exchanger/conveyors;
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= An auger-type heat-exchanger-conveyor that effects fines heating
and coalesced product transport;
= A screen with openings sized to separate the heated fines from the
coalesced product;
= A bucket elevator to transport the heated fines to a pug-mill
type mixer;
= A dispenser that adds a controlled quantity of a solution of a
wet-tack lubricant and protein;
= A hopper to feed metered amounts of an alkali compound to the
mixer; and
= A compression-type dewatering and coalition apparatus, such as the
briquetting mill indicated.
Operation: When the feedstock is coal fines, the above listed
components cooperate to produce a synthetic fuel; Raw moist coal fines are
stored in
and dispensed from the hopper at a measured rate onto a belt-type conveyor,
which
transports the fines now co-mingled with a hot coalesced syn-fuel product to
an
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auger-type heat-exchanger-conveyor that effects heat transfer to the fines
from
coalesced syn-fuel product with a beginning temperature of about 220 F. These
2
materials are churned in the conveyor to expedite fines heating, which is
separated by
a screen from the syn-fuel product, and then delivered by a bucket elevator to
a pug-
mill type mixer, in which it is mixed with metered amount of a solution of
protein
and a wet-tack lubricant from a tank and a measured quantity of an alkali
compound
from a storage bin dispenser. This warm mixture is then fed to and coalesced
in a
compression-type apparatus, such as the symbolized briquetting mill, which
yields a
syn-fuel product heated to about 220 F that is then discharged onto the system
conveyor.
It should be noted that many different equipment types, designs and
component arrangements can be employed to achieve the desired transfer of heat
to
the incoming minerals feedstock.
DETAILED DESCRIPTION OF THE INVENTION
The water factor: Many industrial feedstocks are refined or processed in water
- a medium present in and native to many raw materials. While water is
conducive -
and often essential - to many manufacturing operations, including
purification,
product shaping and reaction chemistry, problems arise when the water in a
feedstock
or nascent product must be reduced or removed. In raw materials that range
from
mining debris to industrial and farm byproducts, the amount of water present
often
dictates whether an otherwise valuable resource will be recovered and
productively
used - or simply abandoned.
A distinction is often made between `free' water and the `inherent', or bound,
moisture - that together constitute `total water'. Because both finely divided
lignocellulosics and particles of chemically inert minerals have minute
capillaries and
pores that hold water tenaciously, no free-water removal procedure (except
prolonged
thermal treatment) is ever totally effective. But the exact amount of free
water in, or
expressed from, the particulate mixture is irrelevant to the process of the
present
invention; in this new process, the amount of free water depends on, and must
be
adjusted to, the viscosity, or consistency, best suited to the coalition
apparatus
employed - almost every type of which has a different preferred consistency
range.
As the term infers, an ostensibly-dry material is dry to the senses but may
contain
some free water; expressing `essentially all free water' means expelling from
the
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feedstock an amount of water that will achieve an ostensibly dry condition.
Despite a water content of 30-35%, over 300 million tons of Powder River
Basin (PRB) coal - not including fines left at the mine - was produced and
sold in
Wyoming in 1998 at spot price of $3.25 to $3.75/ton. Because of its low sulfur
content, ever-larger amounts of PRB coal is being bought by eastern utilities -
although the immured water reduces combustion efficiency, adds non-useful
weight,
and invites rail-car & stock-pile freeze-up. These short-comings are tolerated
as part
of a least-cost solution for achieving compliance with EPA emission limits;
SO2
allowances (credits) earned when low sulfur coat is burned are sold or used to
offset
burning coat with a higher BTU and sulfur content.
An inevitable side effect of expanded mining is a glut of coal fines; an
estimated 40 x 106 tons of fines were generated last year in Wyoming alone.
The
disproportionately large amount of water that clings to the surface of very
small
particles makes the discard of these fines an economic necessity: The cost of
drying
exceeds the value of the salvaged material! But even if water removal cost was
not
prohibitive, the ability of PRB coal to rapidly re-absorb moisture from the
atmosphere would make drying impractical. Consequently, coal producers are
forced
to accept the cost of shipping water, and utilities with older, less flexible,
equipment
must de-rate their boilers to burn this water-laden fuel.
Water-related issues become more acute when coal-fines must be
reconstituted into an insoluble product able to withstand wet and cold weather
without fracturing or re-absorbing significant moisture.
The water content and composition of PRB coal fines, as noted in the As
Received column of Table 1., coupled with a low market price, make this debris
a
near-ideal feedstock for syn-fuel. Introduction of this new syn-fuel making
process
would provide low cost means for using the entire mined product, and for
meeting
the ever-more-stringent EPA emission standards and/or obtaining valuable SO2
allowances. An unexpected bonus is provided by the reaction between the coal's
sulfur and the alkali of the binding agent, which converts unwanted gas to
gypsum
during combustion.
The US Congress addressed the economic barriers confronting new uses of
coal with IRS Code 29, which grants tax credits for converting coal to syn-
fuel. To
qualify a plant for tax credits, a request detailing the new syn-fuel's
properties - with
scientific evidence of a change in chemical composition - must be approved by
the
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IRS (at 11,000 BTU/lb, this credit is now more than $25/ton).
R&D, tightly focused on meeting the IRS product-qualifying criteria at
minimum cost, led to the novel set of innovations that comprise the syn-fuel
making
process disclosed herein, which will, it is expected, enable the profitable
manufacture
of syn-fuel from water-laden coal-fines without regard to rank or source - and
without tax credits. Surprisingly, the invention was found to embrace not only
the
agglomeration of particles of chemically-inert materials, such as coal, but
the making
of composite materials from particulated lignocellulosics. Distinction is made
between agglomerates and composite based on how particles are bonded: in the
former, particles are bound to each other with a binding agent; in a composite
the
particles are embedded, or held, within a binding agent matrix. The
lignocellulosic
residues of field, forest, farm and paper-making often contain an amount of
free
water - naturally, or added during refining- that makes their use economically
marginal or unacceptable.
The term particulate, as it is used herein, means either a finely-divided
lignocellulosic fiber with an average length of less than about 3/4" with an
L/D ratio of
no less than about 20, or a particle of a chemically inert substance, i.e., an
insoluble,
non-reactive, normally infusible material that is no greater than about one cm
across.
The making of composite materials is described in Applicant's aforementioned
US
patent NQ 5,582,682, titled, "A Process and a Composition For Making
Cellulosic
Composites".
A key element of this invention - heat-less dewatering - is achieved by
treating coal fines with a dilute solution of polyethylene oxide (PEO),
a.hydrophuilic
water-soluble polymer. About 150-400 parts PEO (5 1,000,000 molecular weight)
per million parts coal (wt), or 0.3 - 0.8 lbs PEO/ton of coal fines, are
needed to
facilitate the expression of about 85-97% of the coal's free-water under
compressive
forces typically found in belt presses, extruders and briquette/pellet mills
(200-300
tons). The temperature of syn-fuel exiting a briquetting press driven by a 300
HP
motor is about 190-240 F.
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TABLE 1. PROXIMATE ANALYSIS & VALUE - WYODAK (PRB) COAL & SYN-FUEL
Properties As Received (wt %) Syn-Fuel - Dry Basis
Total Moisture 26.43 - - (wt %)
5 Volatile Matter 30.31 41.20
Fixed Carbon 38.76 52.70
Ash 4.50 6.11
Heating Value, BTU/lb (MJ/kg) 8400 (20.51) 11,418 (27.88) Inherent
Moisture 15.53 15.53
Market Value mine .$/ton $3.50 1.4.5 0 est.
ANALYSIS: The Market Value estimate assumes a 11,000 BTU syn-fuel product with
a selling price
of about $14.50/ton (mine) - based on a rail-delivery distance equal to coal
with the same BTU
content from Unita Basin-Colorado. At break-even, a liberal allowance of
$8/ton total for binding
agent and Wyodak coal fines allows a comfortable margin of $6.50/ ton of syn-
fuel for other
operating costs (labor, energy, repairs, etc,.), leaving the $25/ton tax
credit (if available) intact.
The absolute, or effective, amounts of PEO and binding agent required
depend on particulate characteristics, such as, particle size and surface
area,
absorbency and porosity. Although PEO is a known coal-fines dewatering aid, it
was
never previously used in combination with a particulate binder - presumably
because
of its solubility and its purported tendency to resist and/or defeat adhesion.
Manufacturing syn-fuel from Wyhodak fines should be profitable enterprise
(Table 1., Analysis). . A product with = 15.5% inherent moisture made from
fines
originally containing 26/4% water would justify an increase of = $11/ton, from
$3.50/ton to $14.50/ton - based on 8400 BTU/lb coal and syn-fuel at = 11,000
BTU/lb. At break-even (an unlikely, pessimistic case), a 1 million ton/yr
plant would
provide a $25 MM tax credit, plus income of $12-14 MM from sales of about 1
million tons of syn-fuel.
Noteworthy findings made during the development of this invention, include:
Virtually all free water can be expressed from finely divided particulate -
lignocellulosic or minerals - when it is treated with a solution of an
appropriate wet-
tack lubricant (e.g., PEO);
= An appropriate wet tack lubricant (e.g., PEO), despite its lubricity, does
not
inhibit the bonding of particulate into an insoluble agglomerate of a
composite
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material;
= Soluble protein, when admixed and coalesced with a mixture of a solution of
PEO, mineral particulate and line, will form insoluble and impermeable
interparticle
bonds within an agglomerate;
= No heat, except that generated by friction in the coalition apparatus and
transferred to the coal fine, is needed to create a merchantable medium-BTU
syn-fuel
product.
The fundamental objective of this invention is provision of a technically
superior and less costly means for dewatering marginal value particulate
materials,
such as coal fines, and reconstituting such materials into more convenient and
valuable forms, e.g., insoluble and impermeable agglomeratges of solid
synthetic
fuel. Subservient objectives include provision of-
. A novel biomass-based binding agent that is useful in the aforesaid
reconstitution process and does not entail a heating or drying step per se;
. A process of making a synthetic fuel product from coat-fines ordinarily
abandoned;
= A process for making composite materials from marginal value
lignocellulosics.
In accordance with the above objectives, this invention provides a novel and
low-cost bio-based binding-agent and a new manufacturing process which -
together
with orthodox production equipment - comprise a unique system for making
products from a variety of particulate feedstocks, including finely-divided
lignocellulosic fiber and particles, or fines, of chemically-inert minerals.
30
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12
MATERIALS AND EXAMPLES
Table 2. SUMMARY: COMPOSITION INGREDIENTS EVALUATED
I. PROTEIN-RICH INGRED.: Concentration Cost ('1-10) Comments Utility (1-10)
1. Dairy: a.Whey Pro Concen P = 34% min 5 Regional Supply? 6
b. Whey Protein Isolate P = 95% 9 9
2. Agric: a. Soy Bean Flour P = 34% 2 Univ. Available 7
b. Soy Protein Isolate P = 93% min 8 Specialty Product 10
c. Soy Protein Concentrate P = 60% 4' Specialty Product 8
II. INGREDIENT:: ALKALINE:
1 Sodium/Potash-Hydroxide Dry, 100% 1 Poor Results 0
2. Ammonium Hydroxide Aqua, 26 % 1 0
3. Calcium Hydroxide Dry, 100% 1 Large Amount 10
4. Calcium Oxide (Lime) Dry, 100% 0 .9 Performs Best 10
Results Summary: From both a cost and utility perspective, Calcium
Hydroxide, or Oxide, in combination with a soy-bean-derived protein-rich
material,
preferably, soy bean concentrate, or isolate, in a dry weight ration of
protein to
calcium hydroxide of about 12 : 5, provided the best results. As a percentage
of
protein in ingredient I., Table 2., decreases, the effectivity of the
composition as a
binding agent - as indicated by resistance of an agglomerate to water
dissolution and
penetration - also begins to decrease. A composition comprised of soy bean
isolate
and common line was used to obtain the results presented in Table 3., below;
the
isolate form of soy protein was selected for its high protein concentration
and
consistent chemical composition. Inexpensive materials rich in soluble protein
include those derived from dairy products, such as whey, legumes such as
soybeans
and even the liquid waste by products of the meat packing industry.
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Table 3. SUMMARY: PARTICULATE BONDING RESULTS
PARTICULATE PARTICLE A. MOISTURE COMMENTS & B. WRIGHT C. WATER TEST
MATERIAL SIZE PRODUCT NOTES (N) GAIN-H2O
BE60RE AFTER INSOLU. IMPERM.
Wyodak Coal ** 1cm x 0 3-211/0- 15% Excellent Product (1) 0% X X
Pitts..No.8 Coal -250 mesh 22% 11% 0% X
Met, Pet Coke 'k* 3mm x 0 20% 8% Hard, Abrasive (2) 0% X X
Swarf; Fe Ore ** 1cm x 0 18% 6% Oxidizable Prod (2,3) 0% X X
Silica Sand ** -100 mesh 10% 8% Hard, Abrasive (2) 0% X X
WoodFiber; Dust t 5mm x 0 30% 5% Swells in Water (4) 20-30% X (5)--
Straw; Stover 2 cm x 0 z40% 5% " (4) 25% X (5)-
Paper Mill Sludge " " 55% 5% " (5) 15% X (5)-
COM ENTS AND PRODUCT NOTES (TABLE 3.):
A. MOISTURE: Total water content measured both before and after coalition is
listed.
B. WEIGHT GAIN: By coalesced end product after 24 hour immersion.
C. WATER TEST: Resistance of coalesced product to dissolution ion, and
penetration by, water.
(1) Examples represent many coal ranks tested; all yielded an excellent, IRS
qualified, syn-fuel.
(2) Along with metallic ores, inert listed materials produced hard and very
abrasive products.
(3) Due to high pH, these materials are susceptible, after coalition and over
time,
to oxidation.
(4) Immersed in water, these materials imbibe water, gain weight, and expand
linearly, z 25%.
(5) Inert constituents and fillers reduce swelling tendencies of coalesced
sludge.
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** Agglomerates were previously made with high temperature process of
Ferretti,
US N2 5,371,194.
t Cellulosic composites previously made with high temperature process of
Ferretti,
US Na 5,582,682.
GENERAL PROCEDURES:
INGREDIENTS EVALUATION (TABLE 2.): The consistent composition of
soy protein isolate made it the reagent of choice in these trials; only the
least
expensive, alkaline materials were utilized.
COALESCED PRODUCT TRIALS (TABLE 3.): Excellent products were
obtained with all mineral materials; a limitation (i.e., permeability) was
observed in
the lignocellulosic composites unless a hydrophobizing agent was added to the
feedstock mixture, or a coating was applied to the product.
Making insoluble and impermeable medium BTU syn-fuel briquettes from
moist Wyodak (PRB) coal fines with a bio-based binding agent is the preferred
embodiment of this invention. It entails mixing an effective amount of the
binding
agent - composed of lime and soy protein in a dry weight ration of 5 : 12,
respectively - with coal fines that have been treated with a quantity of an
aqueous
solution of polyethylene oxide sufficient to facilitate expression of 85-95%
of the
free water contained in the fines mixture during agglomeration with a
briquetting
press.
