U.S. patent application number 11/249105 was filed with the patent office on 2006-08-17 for method of using environmentally benign anti-icing or deicing fluids employing industrial streams comprising hydroxycarboxylic acid salts and/or other effective deicing/anti-icing agents.
Invention is credited to Axel Johnson, William Ricks, Richard Sapienza.
Application Number | 20060180786 11/249105 |
Document ID | / |
Family ID | 36814761 |
Filed Date | 2006-08-17 |
United States Patent
Application |
20060180786 |
Kind Code |
A1 |
Sapienza; Richard ; et
al. |
August 17, 2006 |
Method of using environmentally benign anti-icing or deicing fluids
employing industrial streams comprising hydroxycarboxylic acid
salts and/or other effective deicing/anti-icing agents
Abstract
The present invention provides methods for use of novel deicing
and anti-icing compositions based on by-produce of
off-specification materials from biodegradable and renewable
sources and which also can be used in a variety of other
services.
Inventors: |
Sapienza; Richard;
(Shoreham, NY) ; Johnson; Axel; (Babylon, NY)
; Ricks; William; (Westerville, OH) |
Correspondence
Address: |
HEDMAN & COSTIGAN P.C.
1185 AVENUE OF THE AMERICAS
NEW YORK
NY
10036
US
|
Family ID: |
36814761 |
Appl. No.: |
11/249105 |
Filed: |
October 12, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11048946 |
Feb 2, 2005 |
|
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11249105 |
Oct 12, 2005 |
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Current U.S.
Class: |
252/70 |
Current CPC
Class: |
C09K 3/185 20130101;
C09K 3/18 20130101 |
Class at
Publication: |
252/070 |
International
Class: |
C09K 3/18 20060101
C09K003/18 |
Claims
1-52. (canceled)
53. A method for lowering the pour point of biodiesel, said method
comprising preventing or reducing crystallization of fatty acids,
esters or alkaline salts of fatty acids in the biodiesel product by
adding to said biodiesel an effective crystallization reducing or
preventing amount of a composition, said composition comprising:
(i) a stream comprising biodegradable, soluble organic acid salts
and/or esters produced during the course of a fermentation process
by reaction with organic acids produced by said fermentation
process, or by reaction with organic acids contained in an effluent
from a fermentation process; (ii) streams comprising biodegradable,
soluble organic acid salts and/or esters comprising or produced
from monomers, intermediates and/or polymers contained in or
derived from waste streams derived from polymerization processes;
(iii) streams comprising polyhydroxy compounds produced during the
course of a fermentation and/or enzyme catalyzed reaction process
in which the substrate consists essentially of a carbohydrate plus
necessary minerals and other nutrients; or (iv) mixtures of two or
more of i, ii and iii.
54. A method as defined in claim 53 wherein said composition is
combined with an effective amount of an organic polymeric component
selected from the group consisting of polyhydroxycarboxylic acids,
methylmethacrylates, polyhydroxyalkanoates, polycaprolactone, and
other synthetic and naturally-derived biodegradable polymers.
55. A method as defined in claim 53 wherein said composition is
combined with an effective amount of pour point depressants the
reducing amount of non-biodegradable components.
56. A method as defined in claim 53 further comprising a
non-aqueous carrier fluid.
57. A method as defined in claim 56 wherein said inert non-aqueous
carrier fluid is selected from the group consisting of diesel fuel,
kerosene and common aromatic and agricultural solvents such as
turpentine, limonene, or pinene.
58. A method as defined in claim 53 wherein said composition is
combined with an effective freezing point reducing amount of an
organic component selected from the group ethyl lactate, tributyl
citrate, glycerol or glycol lactate, ethyl glycinate, ethyl
levulinate, ethylenecarbonate, glycerin carbonate, pipecolic acid
and its esters, tetrahydrofurfuryl acetate, tetrahydrofurfurly
tetrahydrofuroate, glucose glutamate; acetals and ketals of
glycerol such as 2,2dimethyl 1,3dioxolane 4-methanol.
59. A method for preventing crystals of water and/or wax in jet
and/or diesel fuel that can clog fuel filters, said method
comprising adding to said jet and/or diesel fuel an effective
crystal preventing amount of a composition as defined in claim
53.
60. A method as defined in claim 59 wherein said composition is
combined with an effective amount of pour point depressants the
reducing amount of non-biodegradable components.
61. A method as defined in claim 59 wherein said composition
further comprising a non-aqueous carrier fluid.
62. A method as in claim 61 wherein said inert non-aqueous carrier
fluid is selected from the group consisting of jet fuel, diesel
fuel, kerosene and common aromatic and agricultural solvents such
as turpentine, limonene and pinene.
63. A method for lowering the pour point of vegetable oil esters,
said method comprising preventing or reducing crystallization of
fatty acids, esters or alkaline salts of fatty acids in the
vegetable oil product by adding a compound that inhibits
crystallization said compound being selected from the group
consisting of esters of hydroxycarboxylic acids with or without an
esterified polymer or unconverted biodegradable polymer.
64. A liquid material as defined in claim 63 wherein said
composition is combined with an effective freezing point reducing
amount of an organic component selected from the group ethyl
lactate, tributyl citrate, glycerol or glycol lactate, ethyl
glycinate, ethyl levulinate, ethylenecarbonate, glycerin carbonate,
pipecolic acid and its esters, tetrahydrofurfuryl acetate,
tetrahydrofurfurly tetrahydrofuroate, glucose glutamate; acetals
and ketals of glycerol such as 2,2dimethyl 1,3dioxolane 4-methanol.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to deicing fluid compositions
and methods for deicing surfaces and for preventing ice formation
(anti-icing) on surfaces or within aqueous fluids and preventing
crystal formation within non-aqueous fluids. More particularly the
present invention relates to deicing/anti-icing fluid compositions
comprising hydroxycarboxylic acid salts and/or other effective
deicing and/or anti-icing agents obtained as products or
by-products of industrial and/or fermentation processes.
BACKGROUND OF THE INVENTION
[0002] Freezing point lowering compositions are in widespread use
for a variety of purposes, especially to reduce the freezing point
of an aqueous system so that ice cannot be formed or to melt formed
ice. Generally, freezing point lowering compositions depend for
their effectiveness upon the molar freezing point lowering effect,
the number of ionic species that are made available and the degree
to which the compositions can be dispersed in the liquid phase in
which the formation of ice is to be precluded and/or ice is to be
melted.
[0003] The most pervasive of the commonly used products for deicing
are common salt, calcium chloride, magnesium chloride and urea,
with common salt (sodium chloride) being the least expensive and
most commonly used. Common salt widely is used to melt ice on road
surfaces and the like. In this manner, the salt forms a solution
with the available liquid in contact with the ice and thereby forms
a solution with a lower freezing point than the ice itself so that
the ice is melted. Chloride salts, however, suffer from relatively
severe drawbacks, such as the harmful effects on surrounding
vegetation by preventing water absorption in the root systems, the
corrosive effects on animal skin, such as the feet of animals,
clothing, roadways and motor vehicles, and the deleterious effects
on surface and ground water. Thus, any new method of deicing or new
deicing composition that can reduce the amount of chloride salts,
or eliminate chloride salts entirely, would solve a long felt need
in the art.
[0004] Other inorganic salts also are known to be useful as
freezing point lowering agents such as, potassium phosphates,
sodium phosphates, ammonium phosphates, ammonium nitrates, alkaline
earth nitrates, magnesium nitrate, ammonium sulfate and alkali
sulfates.
[0005] Another drawback of certain prior art deicing fluids is
their high chemical and biological oxygen demands, which make them
environmentally unfavorable. The glycols are exemplary of deicing
fluids that particularly suffer from this type of environmental
drawback. Thus, any new method of deicing or new deicing
composition that can reduce the chemical or short term biological
oxygen demands also would solve a long felt need in the art.
[0006] Typical aqueous solutions of low freezing point deicing and
anti-icing agents include chloride salt brines, ethylene glycol and
propylene glycol solutions. The use of chloride brines in
anti-icing compounds can reduce, although not eliminate, the
impacts of chlorides when applied as solids for deicing. Brines and
glycol solutions also are employed as components of fluids used to
transfer heat in applications where the fluid may be exposed to
temperatures below the normal freezing point of water as well as
components of drilling fluids employed in oil and gas operations.
Ethylene glycol solutions are well known for use as coolants for
automobiles and the like in regions where the temperature may fall
below the normal freezing point of water. Ethylene and propylene
glycols are used in relatively large quantities at major airports
in northern climates in order to keep air traffic flowing during
inclement weather. The fluids generally are applied to the wings,
fuselage and tail of aircraft and in some instances to the runways
to remove ice. Glycols also are employed as hydraulic fluids.
However, as mentioned above, these glycol compounds likewise have
environmental drawbacks and can be detrimental to aquatic life and
to sewage treatment processes.
[0007] Other prior art deicing fluids, such as mono and polyhydric
alcohols, have toxic effects and high volatility particularly in
the low molecular weight range. Further, some of these may be the
cause of offensive smells and fire danger. Furthermore, mono- and
polyhydric alcohols oxidize in the presence of atmospheric oxygen
to form acids, which can increase corrosion of materials.
[0008] Due to the problems associated with deicing agents as
described above there have been attempts to discover even more
deicing agents. For, example, Kaes, U.S. Pat. No. 4,448,702
discloses the use of a freezing-point lowering composition and
method that calls for the addition of a water soluble salt of at
least one dicarboxylic acid having at least three carbon atoms,
such as a sodium, potassium, ammonium or organoamine salt of
adipic, glutaric, succinic or malonic acid.
[0009] Peel, U.S. Pat. No. 4,746,449, teaches the preparation of a
deicing agent comprising 12-75% acetate salts, trace-36% carbonate
salts, 1-24% formate salts and 1-32% pseudolactate salts that is
prepared from a pulp mill black liquor by fractionating the black
liquor into a low molecular weight fraction and concentrating the
collected low molecular weight fraction to produce the deicing
agent.
[0010] U.S. Pat. No. 4,960,531 teaches that small amounts of methyl
glucosides, i.e., less than 10%, can be employed as a trigger to
conventional salt deicers.
[0011] Back et al., U.S. Pat. No. 5,993,684, teach the use of non
potassium, non-nitrogen organic salts having a molecular weight
less than 201 in anti-icing or deicing applications, but does not
teach the use of by-product streams from industrial or fermentation
processes. Further, Back teaches against the inclusion of potassium
and halide salts or the use of glycol in formulations.
[0012] Parks et al., U.S. Pat. No. 4,501,775, teach the use of
compositions comprising low concentrations of carboxylic acids, for
the specific purpose of application to coal and mineral ores to
insure that any ice formed thereon is physically weak and will not
deter the unloading of the coal or mineral ores. Further, Parks et
al. do not teach the use of by-product streams from industrial or
fermentation processes.
[0013] Roe, U.S. Pat. No. 4,426,409, teaches the use of organic
salts, in formulations for the purpose, as in Parks et al. above,
of reducing the cohesive strength of particles when frozen.
Further, Roe does not teach the use of by-product steams from
industrial and fermentation processes.
[0014] Koefod, U.S. Pat. No. 5,531,931, teaches the use of low
concentrations of water-soluble organic salts selected from the
group consisting of gluconate salts, ascorbate salts, tartrate
salts and saccharate salts in combination with water-soluble rare
earth salts as agents to reduce the corrosive effects of chloride
salts.
[0015] Special mention also is made of the Sapienza patents, U.S.
Pat. Nos. 5,876,621, 5,980,774, 6,129,857, 6,315,919 and 6,506,318,
which disclose especially useful deicing and anti-icing
compositions (each of these references is incorporated herein by
reference).
[0016] Mention also is made of a number of other patents that
employ industrial process streams in preparing deicing and/or
anti-icing compositions. Examples of such patents are Bloomer, U.S.
Pat. No. 6,080,330 (desugared sugar beet molasses); Toth et al.,
U.S. Pat. No. 4,676,918 (alcohol distilling waste); Janke et al.,
U.S. Pat. No. 5,709,812 (whey); Janke et al., U.S. Pat. No.
5,709,813 (vintner's condensed solubles); Janke et al., U.S. Pat.
No. 5,635,101 (corn wet milling process by-products); Bytnar, U.S.
Pat. No. 6,468,442 (corn syrup); and Hartley et al., U.S. Pat. No.
6,299,793 (corn syrup).
[0017] However, there still exists in the art a need for further
improved deicing and/or anti-icing compositions and methods, which
are environmentally benign and/or reduce detrimental environmental
effects and that are relatively inexpensive to obtain. Preferably,
these new and improved compositions are free of or reduce the use
of inorganic salts, are more environmentally benign and are
prepared from relatively inexpensive raw materials while still
possessing desirable freezing point depression properties.
Likewise, there also exists a need in the art for new deicing
and/or anti-icing agents that can be used in combination with prior
art deicing agents such as inorganic salts or glycols, to
substantially reduce the amount of inorganic salts or glycols
needed to accomplish the deicing/anti-icing objectives, and thereby
concomitantly reduce the detrimental environmental effects of the
salts and/or glycols. Surprisingly, the present inventors have
found that compositions disclosed herein meet these needs while
facilitating by-product disposition from production of
hydroxycarboxylic acids and of polymers based upon renewable
resources. Production of biodegradable polymers from agriculturally
derived sources such as lactic acid is an important strategy to
reduce dependence on fossil hydrocarbons for petrochemical
feedstocks, and providing a means for achieving economic value from
by-product and off specification streams of these processes is an
important element in achieving reasonable production economics.
SUMMARY OF THE INVENTION
[0018] The present inventors have found that excellent deicing
compositions comprising hydroxycarboxylic acid salts and/or other
effective deicing/anti-icing agents can be obtained utilizing
streams produced from, or process streams within, industrial and
agricultural processes and in waste streams from such processes.
Hydroxycarboxylic acids, their salts, their esters and other agents
may be contained in said streams, or may be produced by at least
partially reacting hydroxycarboxylic acid(s) or other acids
contained in said streams to produce the corresponding salts or
esters.
[0019] It is therefore one preferred embodiment of the present
invention to provide components of deicing and/or anti-icing
formulations wherein the components comprise hydroxycarboxylic acid
salts produced by reacting hydroxycarboxylic acids produced in
fermenting sugar containing streams to form the salts. The
hydroxycarboxylic acids lactic acid, citric acid, glycolic acid and
gluconic acid often are produced sugar fermentation processes.
[0020] A further preferred embodiment of the present invention is
to provide components of deicing and/or anti-icing formulations
wherein the components comprise hydroxycarboxylic acid salts
produced by reacting hydroxycarboxylic acid recovered from polymer
production. Recovery of lactic acid or glycolic acid from waste
streams or off specification material from the production of
polyglycolate or polylactate polymers with subsequent conversion of
the rejected polymer, lactide dimer or recovered lactic or glycolic
acid to a lactic or glycolic acid salt or ester from the latter is
an example of such an embodiment.
[0021] In yet another embodiment of this invention, off
specification monomers, intermediate streams and product streams
from renewable resource based monomer and polymer production
processes are recovered and modified, if necessary, to provide
effective components of deicing/anti-icing formulations. In
addition to lactic acid based polymers, this field includes other
approaches such as succcinate biodegradable polymers and
biodegradable polytrimethylene terephthalate (PTT) based upon
1,3-propanediol produced by fermentation. Recovered
off-specification intermediates or monomers in many cases can be
used as components of deicing and/or anti-icing agents in
accordance with the present invention.
[0022] In certain cases, streams from petrochemical monomer
production are recovered and used in deicing/anti-icing service.
For example, in production of 1,3-propanediol from butane via
maleic anhydride, the bottoms from 1,3-propanediol fractionation
are used for anti-icing of coal for shipment. Other fossil
hydrocarbon based processes also yield off specification residues
that can be used in this and similar services. The present
invention, however, focuses on the novel and unobvious utilization
of off-specification or by-product streams from biomass processing
used to produce intermediates and monomers for polymer production
and/or processes to produce biodegradable polymers.
[0023] The present invention still further provides a method for
reducing the amount of inorganic salt necessary to achieve
effective deicing and/or anti-icing, comprising adding to the
inorganic salt, an effective freezing point reducing amount of the
hydroxycarboxylic acid salt and/or other agent containing deicing
and/or anti-icing composition alone, or in combination with an
effective freezing point lowering amount of (a) a
hydroxyl-containing organic compound selected from the group
consisting of hydrocarbyl aldosides; sorbitol and other
hydrogenation products of sugars, monosaccharides, maltodextrins
and sucrose; maltitol; glycerol; glycols; monosaccharides and
mixtures thereof, and/or (b) an organic acid salt selected from the
group consisting of a carbonic acid salt, a carboxylic acid salt, a
hydroxycarboxylic acid salt, a dicarboxylic acid salt and mixtures
thereof.
[0024] The compositions of the present invention further may
comprise a variety of other materials to enhance the deicing and
anti-icing performance, such as, but not limited to, coarse solids
to improve vehicle traction, corrosion inhibitors to prevent or
reduce vehicular and infrastructure corrosion and buffers to
control the pH of the compositions.
[0025] The compositions and methods of the present invention can be
applied to a wide variety of surfaces, including both metallic and
non-metallic surfaces of aircraft, which prevents icing, removes
frozen water from the surface and prevents its reformation. The
invention provides for a deicing composition that can be used on
airport runways, bridges, streets, other structures including power
lines and industrial equipment such as the decks and exposed
superstructure of ships, conveyor systems, storage facilities,
support systems and the like. Further, the compositions can be used
in heat transfer applications such as, but not limited to,
automobile radiator coolants, air conditioner fluids and process
heat transfer fluids, and in other applications in which it is
vital or desired to maintain a liquid in the unfrozen or mobile
state, e.g., as in a fire extinguisher, hydraulic fluids, pour
point depressants or in well drilling work fluids, such as those
used in drilling for oil and gas including completion fluids and
workover fluids. This includes non-aqueous solutions, e.g.,
biodiesel or diesel fuel. Additionally, the present invention
provides for an anti-icing composition that can be applied to a
surface, such as bridges, prior to the onset of icing conditions in
order to prevent icing from occurring.
[0026] Still further, the compositions of the present invention can
be used as a deicer and/or anti-icer for pre-harvest fruit and
vegetable crops or other vegetation, such as, but not limited to,
golf course greens.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] The present invention provides novel compositions useful as
deicing agents and/or anti-icing agents and the corresponding novel
methods. The novel compositions of the present invention comprise
hydroxycarboxylic acid salt(s) contained in, or derived from
hydroxycarboxylic acid(s) contained in (1) products or by-products
from fermentation processes and/or (2) products and/or by products
of industrial or agricultural processes. Specific examples are:
Fermentation
[0028] Several hydroxycarboxylic acids, including citric acid,
lactic acid glycolic acid and gluconic acid, are produced by
fermentation processes as are other acids such as succinic acid--a
dicarboxylic acid. The following are examples of such
processes:
Lactic Acid
[0029] Lactic acid commonly is produced by bacterially-conducted
fermentation processes employing carbohydrates as the feedstock.
Commonly, bacteria from the Lactobacillus genus are employed in
these operations.
[0030] The Lactobacillus organisms produce lactic acid and without
a neutralizing agent the pH drops rapidly to a level where the
microorganisms die or cease useful activity. To counteract this
effect, it is usual in these processes to add a neutralizing agent
in order to achieve high overall productivity. The pH values for
fermentation with good productivity typically range from about 5.0
to about 7.0. Good productivity being defined as a production rate
>0.5 grams/liter/hr.
[0031] A common technique has been to add an alkali material during
the fermentation process as a buffering salt to maintain the pH in
the desired region. Frequently calcium hydroxide is added as the
resulting calcium lactate salt has a low solubility and can be
conveniently removed as a solid. This solid then is acidified with
a strong acid, such as sulfuric acid, releasing lactic acid and a
gypsum (calcium sulfate) by-product.
[0032] An alternative approach is to use a material such as
potassium hydroxide as the alkali, which thereby yields a
water-soluble lactate--potassium lactate. This approach is
discussed in Eyal et al. (U.S. Pat. No. 6,229,046) as part of a
strategy to provide a recycle of soluble lactate so as to achieve
the desired lactic acid/lactate equilibrium with a minimum addition
of potassium hydroxide. Eyal et al. combine this approach with
selection of bacteria strains having good levels of productivity at
lower pHs. This approach then requires a separation technique to
separate the lactic acid from the lactate salt. Eyal et al. discuss
several approaches either to remove lactic acid from a lactic
acid/lactate mixture such as the fermentation broth or to remove
the lactate salt.
[0033] Approaches discussed by Eyal et al. for removal of lactate
salt from the fermentation broth include: [0034] (1) Extraction,
employing for example, a quaternary amine such as methyl trioctyl
ammonium chloride. [0035] (2) Solid absorbent, employing for
example, a strong anion exchanger such as fixed quatenary ammonium
compounds. Examples include Amberlite IRA-400 available from Rohm
and Haas Co. of Philadelphia, Pa. [0036] (3) Membrane separation
employing electrodialysis. [0037] (4) Crystallization. [0038] (5)
In addition, water can be removed by distillation or
evaporation.
[0039] If it is desired to produce a lactate salt for use in a
deicing or anti-icing agent of the present invention, a likely
choice would be either sodium or potassium lactate. These products
could be produced employing the techniques described above in
several ways.
[0040] One case is the instance where the desired product would be
a soluble deicing salt such as sodium or potassium lactate. This
could be a seasonal or intermittent use of a process facility
designed for lactic acid production. In this case, where no
production of lactic acid is desired, the simplest approach is to
supply the Lactobacillus with the amount of nutrient carbohydrate
needed to achieve the practical limit of lactic acid/lactate
production, add a caustic such as potassium acetate to control pH,
and when the bacteria has ceased to function, add sufficient
caustic to neutralize some or all of the remaining lactic acid in
order to bring the final pH to the desired level. Depending on the
choice of operating parameters and feeds, the lactate level at the
conclusion of such a process can be 100 g/l (ca 10%) or more. As
sodium or potassium lactate, this could result in a concentration
of 12 -15% or more.
[0041] At a 15% concentration of sodium lactate in water, the
freezing point will be about -7 C, a bit lower than the freezing
point of propylene glycol at the same concentration. We have found
however that even at such a low concentration of KLac, there is a
synergistic effect resulting from addition of this material to
deiciers such as magnesium chloride and sodium chloride brines.
[0042] A dilute stream in the range of 3-10% lactate salt also can
be applied usefully to deicing/anti-icing applications by addition
of other materials useful in preparation of deicing/anti-icing
agents. Examples of such materials include, but are not limited to
sugars, hydrocarbyl aldosides, glycols, glycerol, amino acids amino
acid salts, other hydroxycarboxylic acid salts and mixtures
thereof. Such formulations may be used in a concentrated form as a
non-chloride deicer. Alternatively, such agents may be used to
enhance the properties of other deicing agents such as solid
chlorides or chloride brines.
[0043] If desired, the dilute lactate salt produced in the above
manner may be concentrated further. Any of the number of techniques
discussed by Eyal et al. could be used. A preferable approach could
employ a combination of ultra-filtration and reverse osmosis. A
first stage of ultra-filtration would remove entrained materials
and particulates down to approximately 0.05 microns. This would be
followed by one or more stages of reverse osmosis depending on the
concentration level required or desired. Alternatively, the lactate
salt could be concentrated by evaporation of a portion of the
contained water. The product from such an operation could be used
in applications requiring a concentrated non-chloride
deicing/anti-icing material, such as, but not limited to, airport
runway applications.
Fermentation Involving Industrial and Agricultural Process
Streams.
[0044] Useful materials for deicing/anti-icing use as-is, or for
blending with other components to produce further improved
deicing/anti-icing agents, may be produced from many industrial and
agricultural process streams. Often these streams are of low value,
but contain useful materials that cannot be recovered economically
in their pure form.
[0045] An example is steepwater produced in wet milling of corn.
This process involves a countercurrent flow of water, initially
containing some SO2, and dried corn in a series of tanks at
temperature of 50-55 C. Steeping results in the extraction of
water-soluble components, and microorganisms are present,
especially lactobacilli. The result is a progressive fermentation
of some of the extracted carbohydrates yielding lactic acid.
Normally the steeping process culminates in a concentration step to
yield corn steep liquor known as condensed fermented corn
extractives.
[0046] A study has been made of the progress of steep analyses as
the process proceeds. (Hull, S. R. et al J. Agric. Food Chem. 1996,
44, 1857-1863) Analyses were taken at three stages in the steep
process designated as "early"(1-3hrs), "middle"(14-17 hrs), and
"late"(27-30 hrs). Data for one of the cases studied are presented
below: TABLE-US-00001 Total Dry Solids carbohydrate Amino acids
Lactic acid stage pH g/L g/L g/L g/L Early 3.5 27.5 5.6 8.0 4.0
Middle 4.5 68.9 10.8 21.6 18.4 Late 4.1 112.2 17.2 33.1 28.2
[0047] At any of the stages of production, a useful agent or
component of an agent for deicing/anti-icing can be prepared from
any of these streams by reacting some or all of the acids present
to form the salts--such as sodium or potassium lactate by methods
such as those taught by Sapienza, U.S. Pat. No. 5,876,621. The
carbohydrates and the amino acid salts formed also are useful
components of a deicing agent as also taught in the Sapienza
patents.
[0048] Beyond direct use of the reacted corn steep as a
deicing/anti-icing component or agent, these materials further can
be modified to enhance their value as components of
deicing/anti-icing agents:
[0049] (1) Steepwater removed from the process at any point can be
concentrated by evaporation, either prior to, or after being
reacted to produce the lactates.
[0050] (2) Following removal from the process, the steepwater can
be allowed to continue its fermentation until either the supply of
carbohydrates is exhausted, or the bacilli cease to be viable. This
step can be undertaken after the initial lactic acid is converted
to lactate, thereby insuring an environment suitable for
fermentation to continue.
[0051] (3) Additional carbohydrate can be added to the steepwater
while undergoing processing per (2).
[0052] (4) In any of the above cases, a purer, cleaner product can
be produced by ultra-filtration to remove solids.
[0053] (5) Following (4), the products further can be concentrated
using reverse osmosis to remove water.
[0054] (6) To enhance further the deicing/anti-icing
characteristics, other components taught in the Sapienza patents
can be added to the products of any of the above alternative
approaches. Without limitation these could include, sugars,
hydrocarbyl aldosides, glycerol, a variety of inorganic and organic
soluble salts.
[0055] The above approaches can be applied to a large number of
industrial and agricultural waste or low value streams. In many
cases it will be necessary to introduce appropriate bacilli should
they not occur naturally in the process stream. Examples of such
streams include stillages, such as thin stillage from ethanol
production, agricultural fermentation products such as cheese whey,
sugar containing waste streams from food processing, and molasses
from beet or cane sugar processing.
Recovery of Hydroxycarboxylic Acid Salts and other
Deicing/Anti-Icing Agents from Industrial Processes.
[0056] An example of this approach involves processes under
development and commercialization that employ lactic acid to
produce lactic acid polymers (polylactates polylactic acid-pla) for
use in a variety of industrial and consumer applications.
Production of these polymers typically involves condensation of the
lactic acid monomer to lactide (a dimer/ester), which then is
catalytically converted to the polymer. In this process, waste and
off-specification streams are likely to occur. In the case of the
lactides and pla these materials can be partially or fully
converted to lactate salts or esters, by methods such as those
taught in the Sapienza '621 patent.
[0057] Other synthetic and naturally-derived biodegradable polymers
currently being commercialized include polyglycolide (PGA), closely
related to the lactic acid polymer; the polyhydroxyalkanoates
(PHA), linear polyesters produced in nature by bacterial
fermentation of sugar or lipids, the majority of PHAs are composed
of R(-)-3-hydroxyalkanoic acid monomers ranging from C3 to C14
carbon atoms with variety of saturated or unsaturated and straight-
or branched chain containing aliphatic or aromatic side groups, the
most common type of PHAs is PHB (poly-beta-hydroxybutyrate);
succinate biodegradable polymers employing succinic acid produced
by fermentation. Also DuPont and Tate & Lyle have reported a
fermentation and separation technology that will produce
1,3-propanediol for PTT production. In cases such as these, waste
or off-spec materials from the fermentation or polymerization steps
may be recovered and employed as deicing/anti-icing agents in
accordance with the present invention. Also included within the
scope of the present invention is polycaprolactone (PCL), a
biodegradable thermoplastic polymer derived from the chemical
synthesis of crude oil. Although not produced from renewable raw
materials, it is fully biodegradable.
[0058] The above approaches can be applied to a large number of
biodegradable polymers that include a wide variety of materials
derived from renewable resources, such as starch, cellulose and
polyhydroxy alkanoates and from synthetic means such as polylactic
acid and polycaprolactone. Also, contemplated for use within the
scope of the present invention are lignin-based biodegradable
polymers, soy and other protein-based plastics; polymers based on
synthetic genes and biodegradable polymers from soybeans.
Production of Lactic Acid Salts for Deicing/Anti-Icing Agents as
By-Products of Lactic Acid Production.
[0059] A typical process for lactic acid production has been
described above. This process can be operated to produce lactate
salt as a by-product. As is pointed out in that discussion, the
Eyal et al. patent describes an approach in which the buffering
agent is selected to yield a soluble salt--rather than a
precipitate such as calcium lactate. Examples of such buffering
agents include sodium or potassium hydroxide. In the case described
by Eyal et al., the soluble salt is returned to the fermentation
process after separation from the lactic acid.
[0060] If it is desired to produce the lactate salt, one of the
separation techniques described in Eyal et al. could be employed.
Production of a net yield of lactate salt need not preclude recycle
of lactate to the fermentation process together with the
microorganisms. Following separation of product lactic acid, the
lactate rich stream could be all, or partially sent to an
ultra-filtration stage operated at less than complete recovery of
the lactate salt. The unfiltered portion can then be recycled to
the fermenter thereby avoiding loss of the bacilli.
Production of Lactic Acid Esters for Deicing/Anti-Icing Agents as
By-Products of Lactic Acid Production.
[0061] A commercial process for chemical synthesis of lactic acid
is based on lactonitrile. Hydrogen cyanide is added to acetaldehyde
in the presence of a base to produce crude lactonitrile, which then
is purified and hydrolyzed to lactic acid, either by concentrated
HCl or by H.sub.2SO.sub.4 to produce the corresponding ammonium
salt and lactic acid. Lactic acid then is esterified with methanol
to produce methyl lactate, which is removed and purified by
distillation and hydrolyzed by water under acid catalyst to produce
lactic acid and the methanol.
[0062] Lactic acid has a boiling point of 100.degree. C. which
makes it very difficult to separate from crude lactic acid aqueous
solutions e.g. from fermentation solutions. Crude lactic acid
mixture can be reacted with alcohols like methanol and the like in
a batch reactive distillation apparatus with simultaneous
distillation of the volatile methyl lactate as a distillate. If it
is desired, this process can be operated to produce the methyl
lactate ester as a by-product. To produce other lactate esters
other alcohols can be utilized as would be understood by those of
ordinary skill in the art in light of this detailed disclosure.
Production of Citric Acid Salts or Esters for Deicing/Anti-Icing
Agents as By-Products of Acid Production.
[0063] Another hydroxycarboxylic acid, citric acid or
2-hydroxy-1,2,3-propanetricarboxylic acid, can be isolated from the
juice of citrus fruits by adding calcium oxide (lime) to form
calcium citrate, an insoluble precipitate that can be collected by
filtration; the citric acid can be recovered from its calcium salt
by adding sulfuric acid. Though it does occur naturally in fruits,
most citric acid is produced in refineries all over the world by
fermenting cane sugar, molasses, and dextrose by use of the fungus
Aspergillus niger and can be obtained synthetically from acetone or
glycerol.
[0064] Similar to lactic acid processing, an approach in which the
buffering agent is selected to yield a soluble salt or
ester--rather than a precipitate ester can be employed. Selection
of such buffering agents is well within the skill of one of
ordinary skill in the art.
Gluconic Acid/Gluconate Production.
[0065] Gluconic acid generally is produced by direct
dehydrogenation of d-glucose employing a microorganism--generally
Aspergillus niger--in an aerobic fermentation. The medium typically
consists of d-glucose (lactose), several inorganic salts and corn
steep liquor. The equilibrium between the lactose and gluconic acid
is controlled by the pH and the temperature of the medium.
Generally calcium or sodium gluconate is formed depending on the
alkali used for pH control.
[0066] Following fermentation the broth is filtered and the
microorganisms and other suspended solids are recycled to the
fermenter. The gluconate solution then is evaporated to crystallize
the gluconate and the product is separated by filtation. Sodium
gluconate is considerably more soluble in water than calcium
gluconate, and in that case the residual mother liquor, after
crystal removal, has a significant concentration of sodium
gluconate as well as unconverted sugar. In an operation using a
commercial high glucose corn syrup as the raw material, the
remaining mother liquor has a sodium gluconate concentration of
27-33 weight per cent and 12-17 weight percent of residual
sugars.
[0067] In the production of sodium gluconate, caustic addition
usually is conducted to maintain a pH of about 4-5. This prevents
free caustic in the product, but as a result there is a residual
amount of gluconic acid mother liquor product. This product can be
used as is, but normally would be adjusted to a more neutral or
slightly alkaline pH for deicing use by addition by adding
additional caustic after the crystalline product is removed.
[0068] The corrosion resistance capabilities of sodium gluconate
are well known--including the effects of inclusion of sodium
gluconate in chloride deicing/anti-icing formulations. Surprisingly
we have found that in addition to the corrosion inhibition effects,
this mother liquor is very effective in improving the freezing
point characteristics of chloride formulations. For example, a
solution of magnesium chloride in water has a eutectic temperature
of -34 C. When a mother liquor of the type described above is added
to a magnesium chloride solution in the amount of about 1 part
mother liquor to 3 parts of magnesium chloride, the resulting
mixture has a eutectic temperature of-52 C.
[0069] It is envisioned that any of the compositions of the present
invention can be prepared for use in either a liquid or a solid
format. For instance, the compositions can be prepared as a liquid
by mixing with water and sprayed or spread on surfaces.
Alternatively it can be prepared in a solid form. Optionally, the
solid further may be processed using methods well known in the art
such as, for example, pelletizing, prilling, flaking, or macerating
to provide the formulation in a final useable solid form. Any of
the binders known to those skilled in the art optionally may be
present and either may be inert or may be comprised of components
that actively help lower the freezing point and/or provide improved
traction, for example, cinders, sawdust, sand, gravel, sugars,
maltodextrins, naturally occurring minerals such as magnesium
chloride, trona and mixtures thereof can be used.
[0070] It further is envisioned that the compositions of the
present invention also may comprise corrosion inhibitors. Such
corrosion inhibitors may include, but are not limited to,
inhibitors comprising salts of gluconic acid or inhibitors
comprising salts of monocarboxylic acids.
[0071] The amount of hydroxycarboxylic acid salt(s) ester(s), or
other freezing point lowering consituents required to be effective
in deicing or anti-icing compositions of the present invention that
is required to be can vary over a considerable range.
[0072] It further is contemplated within the scope of the present
invention, that in addition to the process-derived streams
discussed above, the deicing or anti-icing composition can be
combined with an effective freezing point lowering amount of an
additive comprising (a) a hydroxyl-containing organic compound
selected from the group consisting of hydrocarbyl aldosides;
sorbitol and other hydrogenation products of sugars,
monosaccharides, maltodextrins and sucrose; maltitol; glycols;
glycerol; monosaccharides and mixtures thereof, and/or (b) an
organic acid salt selected from the group consisting of a carbonic
acid salt, a carboxylic acid salt, a hydroxycarboxylic acid salt, a
dicarboxylic acid salt and mixtures thereof. The amount of additive
generally ranges from about 0.5 to about 95 weight percent based on
the weight of the additive and by-product.
[0073] Certain of the hydrocarbyl aldosides useful in the practice
of the present invention are non-alkyl aldosides some of which are
known to those of ordinary skill in the art, such as the di- and
polysaccharides. Examples of non-alkyl hydrocarbyl aldosides useful
in the practice of the present invention are the glucofuranoside
sucrose (table sugar), and maltose and higher polyglucosides.
[0074] The hydrocarbyl aldosides also comprise alkyl aldosides.
Alkyl aldosides can be prepared, for example, as described in U.S.
Pat. Nos. 4,223,129 and 4,329,449, which are incorporated herein by
reference. Typical of the alkyl aldosides useful in the practice of
the present invention are alkyl glucosides, alkyl furanosides,
alkyl maltosides, alkyl maltotriosides, alkylglucopyranosides,
mixtures thereof and the like.
[0075] Other hydroxyl-containing compounds useful in the practice
of the present invention are sorbitol and other hydrogenation
products of sugars, monosaccharides, maltodextrins and sucrose such
as maltitol, xylitol and mannitol; glycols such as ethylene glycol
and propylene glycol; glycerols; and monosaccharides. These
materials are available commercially and are well known to those of
ordinary skill in the art.
[0076] The organic salt components useful in the practice of the
present invention include the carboxylic acid salts, the
hydroxycarboxylic acid salts, dicarboxylic acid salts.
[0077] The carboxylic acid salts that are useful in the practice of
the present invention are likewise available commercially and are
known to those skilled in the art. Carboxylic acid salts preferred
for use in the practice of the present invention comprise the
sodium or potassium salts of formates, acetates, propionates,
butyrates and mixtures thereof. Also preferred are potassium
acetate and/or potassium formate.
[0078] The dicarboxylic acid salts that are useful in accordance
with the present invention are available commercially and are known
to those skilled in the art. Preferred dicarboxylic acid salts
comprise sodium and potassium salts of oxalates, malonates,
succinates, glutarates, adipates, maleates, fumarates and mixtures
of any of the foregoing.
[0079] Also useful as a deicing component in certain of the
compositions of the present invention are the high solubility
carbonic acid salts. Preferred carbonate salts for use in the
practice of the present invention are potassium carbonate,
potassium bicarbonate, sodium carbonate and cesium carbonate.
Potassium carbonate especially is preferred.
[0080] Also useful as deicing components in certain compositions of
the present invention are the highly soluble salt forms of sodium
formate, potassium acetate and sodium lactate. In many
applications, the addition of these salts has been found to provide
synergistically unexpected reductions in freezing points.
[0081] The present invention still further contemplates combining
the hydroxycarboxylic acid salt(s) and other effective freezing
point lowering constituents of this invention with other industrial
process streams useful in deicing and/or anti-icing products. For
example, the other industrial process streams may be selected from
any such streams containing the hydroxyl or organic acid compounds
enumerated above including, but not limited to, those selected from
the group consisting of a grain stillage, grain steepwaters, wood
stillage, corn syrups, products of agricultural or milk
fermentation processes, products of sugar extraction processes such
a desugared sugar beet molasses and/or desugared sugar cane
molasses, hydrogenation products of sugars, monosaccharides,
maltodextrins and sucrose and mixtures of any of the foregoing.
These industrial streams may be employed directly, or may be
treated, such as by alcoholysis to convert the hydroxyl containing
compounds to esters, or by reacting convert the organic acids to
anionic organic acid salts, such as with a caustic.
[0082] Generally, the deicing and/or anti-icing agents useful in
the practice of the present invention may be used in solid form,
liquid form or liquid form mixed with water or other carrier
liquids.
[0083] In addition to (a) the certain hydroxyl-containing organic
compounds and (b) the certain organic acid salts, it is
contemplated by the present invention that other organic components
may be included in the deicing and/or anti-icing compositions of
the present invention. Exemplary of such materials are citrate
salts such as sodium citrate; amino acids and their salts such as
lysine glutamate, sodium pyrrolidone carboxylate and sodium
glucoheptonate; lignin components such as lignin sulfonate; boric
acid and its salts; and mixtures of any of the foregoing.
[0084] In the methods of the present invention, the deicing and/or
anti-icing compositions of the present invention are applied, such
as by spraying for liquid forms, or spreading for solid forms, onto
the surface desired to be treated. In the case of deicing, the
surface already has ice formed thereon, and the deicing
compositions of the present invention melt the ice already formed
and further are effective in preventing additional ice formation.
In the case of anti-icing, upon learning of a weather forecast that
predicts possible dangerous icing conditions, the roads, bridges,
airplanes, runways, growing produce or other surfaces can be
pretreated with the anti-icing compositions of the present
invention in similar manner in order to prevent ice formation on
the treated surfaces.
[0085] In the methods of the present invention, the deicing and/or
anti-icing compositions of the present invention also are useful in
reducing the pour point and cold filter plugging point of oils,
particularly environmentally capable oils, such as vegetable oils
and the methyl esters of vegetable oils (such as rapeseed and
soybean oils) that commonly are used as alternative environmentally
compatible diesel fuels (biodiesel). As an ester with or without an
esterified polymer or unconverted biodegradable polymer; product
solubility with diesel, crude oil and common aromatic and
agricultural solvents such as turpentine, limonene, or pinene
interferes with wax crystal growth patterns, thereby these products
prevent interlocking of wax crystals and can be applied as or with
an anti-gel treatment/flow improver/pour point depressant additive
that lowers the temperature at which oil will pour or flow.
Furthermore, this can be used as a method for preventing crystals
of water and/or wax in jet and diesel fuel that can clog the fuel
filters.
[0086] In situations where some inorganic salts, such as, but not
limited to, sodium chloride, magnesium chloride and calcium
chloride, can be tolerated, the present invention provides an
improved method for reducing the amount of salt to be added to
achieve an equivalent or better deicing and/or anti-icing effect,
and thereby reduce the detriment to the environment. Further, as
cited earlier, we have found that addition of the hydroxycarboxylic
acid salt containing streams is effective in achieving the
effective use of these chlorides in temperature regions
substantially below the eutectic points of the simple chloride
solutions.
[0087] The methods of this invention also apply to inhibiting
crystallization in non-aqueous systems. For example we have found
that addition of esters of hydrocarboxylic acid with or without an
esterified hydrocarboxylic acid polymer or unconverted
biodegradable polymer to a biodiesel act to inhibit crystallization
of residual fatty acids and salts of fatty acids (soaps), thereby
reducing the pour point of the biodiesel. For example, a 10%
solution of ethyl lactate or tributyl citrate in a turpentine
carrier along with 1-2% polylactic acid polymer will reduce the
pour point of a soy biodiesel (methyl soyate) by 10 F. Other
vegetable esters such as those used as solvents, lubricants or
additives also can be treated. Successful formulations for the
reduction in pour point for biodiesel and methylsoyate also have
been prepared when combined with petroleum based diesel,
methylmethacrylates and copolymers of ethylene and propylene.
[0088] Many variations of the present invention will suggest
themselves to those skilled in the art in light of the
above-detailed description. For example, the hydroxycarboxylic acid
salt containing streams can be combined with any industrial process
stream that contains carboxylic acid salts, hydroxycarboxylic acid
salts and/or dicarboxylic acid salts in preparing compositions of
the present invention. Additionally, a wide variety of glucosides,
carbonates, hydrocarbyl aldosides, and a variety of combinations of
the components of the present invention may be employed as
additives to the compositions of the present invention. All such
obvious modifications are within the full-intended scope of the
appended claims.
[0089] The above-referenced patents, test methods, and publications
are hereby incorporated by reference.
* * * * *