U.S. patent application number 10/646944 was filed with the patent office on 2004-02-26 for loose fiber adsorbent.
Invention is credited to Brownstein, Jerry M., Brownstein, Kathy R., Hepner, Brent A..
Application Number | 20040035797 10/646944 |
Document ID | / |
Family ID | 25366045 |
Filed Date | 2004-02-26 |
United States Patent
Application |
20040035797 |
Kind Code |
A1 |
Brownstein, Jerry M. ; et
al. |
February 26, 2004 |
Loose fiber adsorbent
Abstract
A sorbent and filter media material produced from a mass of
delustered hydrophobic and lipophilic fibers. In one embodiment the
fibers are mixed together to form a cohesive wad of fibers. The wad
has a substantial volume of internal interstices available to
absorb a liquid hydrocarbon or an organic liquid, and the surfaces
of the fibers also adsorb that liquid. The combination of
adsorption and absorption enables the sorbent to sorb up to twenty
times it own weight of hydrocarbon or organic liquid. Preferably a
majority of the fibers are of a relatively shorter length, while a
minority of the fibers are of a relatively longer length. The
longer fibers help bind the wad together into a cohesive mass that
has a substantial volume of internal interstices. After a short
time during which the hydrocarbon is sorbed, the wadded mass can be
collected, pressed to recover the hydrocarbon, and recycled.
Inventors: |
Brownstein, Jerry M.;
(Issaquah, WA) ; Brownstein, Kathy R.; (Issaquah,
WA) ; Hepner, Brent A.; (Kent, WA) |
Correspondence
Address: |
LAW OFFICES OF RONALD M. ANDERSON
Suite 507
600-108th Avenue N.E.
Bellevue
WA
98004
US
|
Family ID: |
25366045 |
Appl. No.: |
10/646944 |
Filed: |
August 21, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10646944 |
Aug 21, 2003 |
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09875591 |
Jun 6, 2001 |
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6632501 |
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Current U.S.
Class: |
210/691 |
Current CPC
Class: |
B01D 17/0202 20130101;
B01J 20/26 20130101; B01J 20/28023 20130101; C02F 1/681 20130101;
B01J 20/28028 20130101; B01D 39/1623 20130101; C02F 1/285 20130101;
Y10T 442/60 20150401; Y10T 442/696 20150401; B01J 20/28097
20130101; B01J 20/28004 20130101; B01J 20/28033 20130101; B01D
17/0214 20130101; B01D 15/00 20130101; Y10T 428/237 20150115; Y10T
428/239 20150115; Y10T 428/24942 20150115 |
Class at
Publication: |
210/691 |
International
Class: |
C02F 001/28 |
Claims
The invention in which an exclusive right is claimed is defined by
the following:
1. A method for removing a liquid hydrocarbon from a surface
contaminated with the liquid hydrocarbon, comprising the steps of:
(a) collecting the liquid hydrocarbon by: (i) bringing a wadded
mass comprising a plurality of discrete hydrophobic and lipophilic
fibers into contact with the liquid hydrocarbon; (ii) allowing the
wadded mass to absorb the liquid hydrocarbon from the surface that
is contaminated, the liquid hydrocarbon being absorbed into a
plurality of interstices formed between the discrete hydrophobic
and lipophilic fibers within said wadded mass; and (iii) allowing
the wadded mass of discrete hydrophobic and lipophilic fibers to
adsorb the liquid hydrocarbon from the contaminated surface, the
liquid hydrocarbon accumulating upon a plurality of surfaces of the
discrete hydrophobic and lipophilic fibers within said wadded mass;
and (b) mechanically removing said wadded mass of discrete
hydrophobic and lipophilic fibers with the liquid hydrocarbon that
have been absorbed and adsorbed, from the surface to reduce its
contamination.
2. The method of claim 1, wherein said discrete hydrophobic and
lipophilic fibers comprise synthetic fibers.
3. The method of claim 2, wherein said synthetic fibers comprise a
mixture of polyester fibers and nylon fibers.
4. The method of claim 3, wherein said mixture of polyester fibers
and nylon fibers comprises substantially more polyester fibers than
nylon fibers.
5. The method of claim 4, wherein a ratio of polyester fibers to
nylon fibers ranges from about 2:1 to about 4:1.
6. The method of claim 1, wherein said discrete hydrophobic and
lipophilic fibers comprise a mixture of relatively shorter fibers
and relatively longer fibers.
7. The method of claim 6, wherein said relatively longer fibers
bind the relatively shorter fibers into said wadded mass.
8. The method of claim 6, wherein said mixture of relatively
shorter fibers and relatively longer fibers comprise fibers ranging
in length from about 5 mm to about 100 mm.
9. The method of claim 1, wherein the wadded mass of discrete
hydrophobic and lipophilic fibers sorbs up to 25 times its own
weight of the liquid hydrocarbon.
10. The method of claim 1, further comprising the step of
compressing said wadded mass of discrete hydrophobic and lipophilic
fibers to recover the liquid hydrocarbon.
11. The method of claim 1, further comprising the step of
mechanically treating said discrete hydrophobic and lipophilic
fibers before use to increase a surface area of said discrete
hydrophobic and lipophilic fibers.
12. The method of claim 1, wherein the discrete hydrophobic and
lipophilic fibers have been delustered.
13. The method of claim 1, wherein the discrete hydrophobic and
lipophilic fibers have been delustered in a manner that enhances a
cohesion of said wadded mass by increasing a fiber-to-fiber
friction.
14. The method of claim 1, wherein the discrete hydrophobic and
lipophilic fibers have been delustered with titanium dioxide.
15. The method of claim 1, further comprising the step of
processing the discrete hydrophobic and lipophilic fibers to
increase a porosity of said discrete hydrophobic and lipophilic
fibers.
16. The method of claim 1, wherein said wadded mass further
comprises a plurality of discrete hydrophilic fibers.
17. The method of claim 16, wherein said discrete hydrophilic
fibers comprise cotton fibers.
18. The method of claim 16, wherein said wadded mass further
comprises substantially more discrete hydrophobic and lipophilic
fibers than discrete hydrophilic fibers.
19. The method of claim 16, wherein a ratio of said discrete
hydrophobic and lipophilic fibers to said discrete hydrophilic
fibers is about 9:1.
20. The method of claim 1, wherein said discrete hydrophobic and
lipophilic fibers comprise a mixture of fibers having different
cross-sectional diameters.
21. The method of claim 20, wherein said mixture of fibers having
different cross-sectional diameters comprise fibers having
diameters ranging from about 10 .mu.m to about 50 .mu.m.
22. The method of claim 1, wherein the step of bringing the wadded
mass comprising the plurality of discrete hydrophobic and
lipophilic fibers into contact with the liquid hydrocarbon
comprises the step of using a mechanical blower device to
distribute said wadded mass over said contaminated surface.
23. The method of claim 1, wherein said surface that is
contaminated is a surface of a body of water.
24. A method for removing liquid hydrocarbon from a surface of a
body of water contaminated with the liquid hydrocarbon, comprising
the steps of: (a) providing a hydrophobic and lipophilic sorbent
product that includes: (i) a plurality of relatively shorter
hydrophobic and lipophilic fibers having rough, delustered
surfaces; and (ii) a plurality of relatively longer hydrophobic and
lipophilic fibers having rough, delustered surfaces, said
relatively long hydrophobic and lipophilic fibers and said rough,
delustered surfaces binding said plurality of relatively short
hydrophobic and lipophilic fibers and said plurality of relatively
long hydrophobic and lipophilic fibers into a wadded mass, said
wadded mass comprising a plurality of interstitial spaces, said
wadded mass having a density less than that of water, so that said
wadded mass floats on the surface of said body of water; (b)
collecting the liquid hydrocarbon by: (i) bringing said wadded mass
into contact with the liquid hydrocarbon; (ii) allowing the wadded
mass to absorb the liquid hydrocarbon from the surface of said body
of water, absorbed liquid hydrocarbon being absorbed into the
plurality of interstitial spaces within said wadded mass; and (iii)
allowing the wadded mass to adsorb the liquid hydrocarbon from the
surface of said body of water, adsorbed hydrocarbons accumulating
upon said plurality of rough, delustered surfaces of said
relatively shorter hydrophobic and lipophilic fibers and said
relatively longer hydrophobic and lipophilic fibers; and (c)
mechanically removing said wadded mass from the surface of said
body of water.
25. The method of claim 24, wherein the step of allowing the wadded
mass to adsorb the liquid hydrocarbon further comprises the step of
allowing said wadded mass to remain in contact with said surface
for a period of time that is sufficient to enable liquid
hydrocarbon to be absorbed into the interior regions of at least a
portion of the rough, delustered relatively shorter hydrophobic and
lipophilic fibers and the rough, delustered relatively longer
hydrophobic and lipophilic fibers, to a point of saturation.
26. The method of claim 24, wherein a majority of said plurality of
relatively shorter hydrophobic and lipophilic fibers have lengths
ranging from about 10 mm to about 20 mm, and wherein a majority of
said plurality of relatively long hydrophobic and lipophilic fibers
have lengths ranging from about 80 mm to about 90 mm.
27. The method of claim 24, wherein said plurality of relatively
shorter hydrophobic and lipophilic fibers, and said plurality of
relatively longer hydrophobic and lipophilic fibers both comprise
synthetic fibers.
28. The method of claim 24, wherein said plurality of relatively
shorter hydrophobic and lipophilic fibers, and said plurality of
relatively longer hydrophobic and lipophilic fibers each comprise a
mixture of fibers having different cross-sectional diameters, said
cross-sectional diameters ranging from about 10 .mu.m to about 50
.mu.m.
29. The method of claim 24, wherein the absorption and adsorption
processes begin immediately upon contact of the wadded mass with
said liquid hydrocarbon and are substantially complete in one
minute.
30. A method for removing a liquid hydrocarbon from a surface of a
body of water contaminated with the liquid hydrocarbon, comprising
the steps of: (a) providing a hydrophobic and lipophilic sorbent
product that includes: (i) a plurality of relatively shorter
hydrophobic and lipophilic fibers, said relatively shorter
hydrophobic and lipophilic fibers each comprising rough, delustered
surfaces, a majority of said plurality of relatively shorter
hydrophobic and lipophilic fibers having lengths ranging from about
10 mm to about 20 mm; and (ii) a plurality of relatively longer
hydrophobic and lipophilic fibers; said relatively longer
hydrophobic and lipophilic fibers each comprising rough, delustered
surfaces, a majority of said plurality of relatively longer
hydrophobic and lipophilic fibers having lengths ranging from about
80 mm to about 90 mm, said relatively longer hydrophobic and
lipophilic fibers and said rough delustered surfaces binding said
plurality of relatively shorter hydrophobic and lipophilic fibers
and said plurality of relatively longer hydrophobic and lipophilic
fibers into a wadded mass, said wadded mass comprising a large
number of interstitial spaces; said wadded mass having a density
that enables said wadded mass to float on the surface of said body
of water; (b) collecting the liquid hydrocarbon by: (i) bringing
said wadded mass into contact with the liquid hydrocarbon; (ii)
allowing the wadded mass to absorb the liquid hydrocarbon from the
surface of said body of water, the liquid hydrocarbon being
absorbed into the plurality of interstitial spaces within said
wadded mass; and (iii) allowing the wadded mass to adsorb the
liquid hydrocarbon from the surface of said body of water, the
liquid hydrocarbon accumulating upon said plurality of rough,
delustered surfaces of said relatively shorter hydrophobic and
lipophilic fibers and said relatively longer hydrophobic and
lipophilic fibers; and (c) mechanically removing said wadded mass
from the surface of said body of water.
31. A method for removing liquid hydrocarbon from a surface
contaminated with said liquid hydrocarbon, comprising the steps of:
(a) providing a hydrophobic and lipophilic sorbent product that
includes: (i) a plurality of relatively shorter hydrophobic and
lipophilic fibers, a majority of said plurality of relatively
shorter hydrophobic and lipophilic fibers having lengths ranging
from about 10 mm to about 20 mm; and (ii) a plurality of relatively
longer hydrophobic and lipophilic fibers, a majority of said
plurality of relatively longer hydrophobic and lipophilic fibers
having lengths ranging from about 80 mm to about 90 mm, said
relatively longer hydrophobic and lipophilic fibers binding said
plurality of relatively shorter hydrophobic and lipophilic fibers
and said plurality of relatively longer hydrophobic and lipophilic
fibers into a wadded mass, said wadded mass comprising a plurality
of interstitial spaces; (b) collecting the liquid hydrocarbon by:
(i) bringing said wadded mass into contact with the liquid
hydrocarbon; and (ii) allowing the wadded mass to adsorb the liquid
hydrocarbon from the surface that is contaminated, the liquid
hydrocarbon accumulating upon surfaces of said relatively shorter
hydrophobic and lipophilic fibers and said relatively longer
hydrophobic and lipophilic fibers; and (c) mechanically removing
said wadded mass from the surface.
32. The method of claim 31, further comprising the step of encasing
said wadded mass in a boom.
33. The method of claim 31, further comprising the step of encasing
said wadded mass in a pillow.
34. The method of claim 31, wherein the step of providing a
hydrophobic and lipophilic sorbent product comprises providing said
hydrophobic and lipophilic sorbent product in a compressed state,
and further comprising the step of decompressing said hydrophobic
and lipophilic sorbent product before bringing the liquid
hydrocarbon into contact with said wadded mass.
35. A method for removing liquid hydrocarbon from a surface
contaminated with the liquid hydrocarbon, comprising the steps of:
(a) providing a hydrophobic and lipophilic sorbent product
including a plurality of relatively shorter hydrophobic and
lipophilic fibers and a plurality of relatively longer hydrophobic
and lipophilic fibers, said relatively longer hydrophobic and
lipophilic fibers binding said plurality of relatively shorter
hydrophobic and lipophilic fibers and said plurality of relatively
longer hydrophobic and lipophilic fibers into a wadded mass, said
wadded mass having a plurality of interstitial spaces, wherein said
hydrophobic and lipophilic sorbent product is characterized by its
ability to sorb the liquid hydrocarbon, such that a weight of the
liquid hydrocarbon sorbed relative to a weight of the hydrophobic
and lipophilic sorbent product is generally constant; (b)
collecting the liquid hydrocarbon by: (i) bringing said wadded mass
into contact with the liquid hydrocarbon; (ii) allowing the wadded
mass to absorb the liquid hydrocarbon from the surface that is
contaminated, the liquid hydrocarbon being absorbed into the
plurality of interstitial spaces within said wadded mass; and (iii)
allowing the wadded mass to adsorb the liquid hydrocarbon from the
surface that is contaminated, the liquid hydrocarbon accumulating
upon surfaces of said relatively shorter hydrophobic and lipophilic
fibers and said relatively longer hydrophobic and lipophilic
fibers; and (c) mechanically removing said wadded mass from the
surface.
36. The method of claim 35, wherein the hydrophobic and lipophilic
sorbent product is capable of removing over 80% of the hydrocarbon
product from said surface that is contaminated when said
hydrophobic and lipophilic sorbent product is applied to said
surface at a rate of approximately 2.5% of the weight of the
hydrocarbon product to be removed.
37. The method of claim 35, wherein the hydrophobic and lipophilic
sorbent product is capable of removing over 96% of the hydrocarbon
product from said surface that is contaminated when said
hydrophobic and lipophilic sorbent product is applied to said
surface in an amount equal to about 5% of the weight of the
hydrocarbon product to be removed.
38. A sorbent wadded mass suitable for adsorbing a liquid
hydrocarbon that is contaminating a body of water, said sorbent
mass comprising: (a) a plurality of relatively shorter hydrophobic
and lipophilic fibers, said relatively shorter hydrophobic and
lipophilic fibers having rough, delustered surfaces; (b) a
plurality of relatively longer hydrophobic and lipophilic fibers,
said relatively longer hydrophobic and lipophilic fibers having
rough, delustered surfaces, said relatively longer hydrophobic and
lipophilic fibers and said rough delustered surfaces binding said
plurality of relatively shorter hydrophobic and lipophilic fibers
and said plurality of relatively longer hydrophobic and lipophilic
fibers into a wadded mass, said wadded mass including a plurality
of interstitial spaces and having a density that is substantially
less than that of water, so that said wadded mass is adapted to
float on a surface of a body of water; and (c) a porous cover
encasing said wadded mass.
39. The sorbent wadded mass of claim 38, wherein said porous cover
comprises a boom.
40. A sorbent wadded mass suitable for adsorbing a liquid
hydrocarbon product, said sorbent mass comprising: (a) a plurality
of relatively shorter hydrophobic and lipophilic fibers, a majority
of said plurality of relatively shorter hydrophobic and lipophilic
fibers having lengths ranging from about 10 mm to about 20 mm; and
(b) a plurality of relatively longer hydrophobic and lipophilic
fibers, a majority of said plurality of relatively longer
hydrophobic and lipophilic fibers having lengths ranging from about
70 mm to about 90 mm, said relatively longer hydrophobic and
lipophilic fibers binding said plurality of relatively shorter
hydrophobic and lipophilic fibers and said plurality of relatively
longer hydrophobic and lipophilic fibers into said wadded mass.
41. The sorbent wadded mass of claim 40, wherein said plurality of
relatively shorter hydrophobic and lipophilic fibers and said
plurality of relatively longer hydrophobic and lipophilic fiber
comprise synthetic fibers.
42. The sorbent wadded mass of claim 41, wherein said synthetic
fibers comprise a mixture of polyester fibers and nylon fibers.
43. The sorbent wadded mass of claim 42, wherein said mixture of
polyester fibers and nylon fibers comprises substantially more
polyester than nylon.
44. The sorbent wadded mass of claim 43, wherein a ratio of
polyester fibers to nylon fibers ranges from about 2:1 to about
4:1.
45. The sorbent wadded mass of claim 40, wherein said plurality of
relatively shorter hydrophobic and lipophilic fibers and said
plurality of relatively longer hydrophobic and lipophilic fibers
have rough, delustered surfaces, said rough, delustered surfaces
providing fiber-to-fiber traction that enhances a cohesiveness of
said wadded mass, said rough, delustered surfaces further enhancing
a volume of interstitial space within said wadded mass, said
interstitial space enabling said sorbent mass to also absorb said
liquid hydrocarbon, the absorption occurring within said
interstitial spaces.
46. The sorbent wadded mass of claim 40, wherein said relatively
shorter hydrophobic and lipophilic fibers and said relatively
longer hydrophobic and lipophilic fibers comprise fibers ranging in
length from about 5 mm to about 100 mm.
47. The sorbent wadded mass of claim 40, wherein said wadded mass
is capable of adsorbing an amount of liquid hydrocarbon up to about
25 times a weight of said wadded mass.
48. A kit adapted for removing a liquid hydrocarbon from a
contaminated surface, comprising: (a) a sorbent wadded mass that
includes: (i) a plurality of relatively shorter hydrophobic and
lipophilic fibers; (ii) a plurality of relatively longer
hydrophobic and lipophilic fibers, said relatively longer
hydrophobic and lipophilic fibers binding said plurality of
relatively shorter hydrophobic and lipophilic fibers and said
plurality of relatively longer hydrophobic and lipophilic fibers
into said wadded mass; and (b) instructions for employing said
sorbent wadded mass to remove a liquid hydrocarbon from a surface
that is contaminated.
49. The kit of claim 48, wherein said instructions generally
instruct a user to: (a) distribute said wadded mass so that it
contacts a liquid hydrocarbon; (b) allow the wadded mass to sorb a
liquid hydrocarbon from the surface that is contaminated; and (c)
remove said wadded mass and liquid hydrocarbon that is sorbed
thereby from the surface.
50. A kit adapted for removing a liquid hydrocarbon from a
contaminated surface comprising: (a) a sorbent that includes: (i) a
plurality of relatively shorter hydrophobic and lipophilic fibers,
said relatively shorter hydrophobic and lipophilic fibers having
rough, delustered surfaces; and (ii) a plurality of relatively
longer hydrophobic and lipophilic fibers, said relatively longer
hydrophobic and lipophilic fibers having rough, delustered
surfaces, said relatively longer hydrophobic and lipophilic fibers
and said rough, delustered surfaces binding said plurality of
relatively shorter hydrophobic and lipophilic fibers and said
plurality of relatively longer hydrophobic and lipophilic fibers
into a wadded mass, said wadded mass extending into three
dimensions and having sufficient flexibility to conform to an
irregularly contoured surface, said wadded mass having a plurality
of interstitial spaces; and (b) instructions for employing said
sorbent to remove a liquid hydrocarbon from a surface that is
contaminated thereby.
51. The kit of claim 50, wherein said instructions generally
instruct a user to: (a) distribute said wadded mass on the surface
that is contaminated; (b) allow the wadded mass to absorb and
adsorb a liquid hydrocarbon from the contaminated surface; and (c)
remove said wadded mass with the liquid hydrocarbon that was
absorbed and adsorbed from the surface.
52. The kit of claim 50, wherein a majority of said plurality of
relatively shorter hydrophobic and lipophilic fibers have lengths
ranging from about 10 mm to about 20 mm, and wherein a majority of
said plurality of relatively longer hydrophobic and lipophilic
fibers have lengths ranging from about 80 mm to about 90 mm.
53. A method of manufacturing a sorbent wadded mass, said method
comprising the steps of: (a) providing a quantity of delustered
hydrophobic and lipophilic fibers, wherein a delustering process
employed to deluster the quantity of hydrophobic and lipophilic
fibers both enhances their porosity and increases a surface area
associated with the quantity of hydrophobic and lipophilic fibers;
(b) processing said quantity of delustered hydrophobic and
lipophilic fibers to produce a majority of hydrophobic and
lipophilic fibers that have relatively shorter fiber lengths, and a
minority of hydrophobic and lipophilic fibers that have relatively
longer fiber lengths; and (c) blending said relatively shorter
fiber lengths and said relatively longer fiber lengths together to
form a sorbent wadded mass characterized as having a substantial
volume of internal interstices, said relatively longer fiber
lengths helping to bind said sorbent matrix together into a
flexible and cohesive mass.
54. The method of claim 53, wherein the majority of said
hydrophobic and lipophilic fibers have a length in the range of
from about 10 mm to about 20 mm, and the minority of said quantity
of hydrophobic and lipophilic fibers have a length in the range of
from about 75 mm to about 90 mm.
55. The method of claim 53, wherein the step of providing a
quantity of delustered hydrophobic and lipophilic fibers comprises
the step of delustering a quantity of synthetic fabric to produce
said quantity of delustered hydrophobic and lipophilic fibers.
56. The method of claim 53, wherein said delustering process
comprises the step of delustering the quantity of hydrophobic and
lipophilic fibers with titanium dioxide.
57. A method of using synthetic fabric scrap as a sorbent material
for a liquid hydrocarbon, comprising the steps of: (a) shredding
said synthetic fabric scrap to produce a mass comprising a
plurality of discrete synthetic fibers; (b) bringing said mass into
contact with a liquid hydrocarbon; (c) allowing said mass to sorb
the liquid hydrocarbon; and (d) mechanically collecting said mass
after the hydrocarbon product has been sorbed by the mass.
58. The method of claim 57, wherein the step of shredding the mass
of synthetic fibers is carried out until said synthetic fibers are
processed into a majority of relatively shorter fiber lengths, and
a minority of relatively longer fiber lengths.
59. The method of claim 58, further comprising the step of blending
said relatively shorter fiber lengths and said relatively longer
fiber lengths together to form a sorbent wadded mass characterized
as having a substantial volume of internal interstices, said
relatively longer fiber lengths helping to bind said sorbent wadded
mass together into a flexible and cohesive mass.
60. The method of claim 57, wherein the step of allowing said
wadded mass to sorb the liquid hydrocarbon comprises the steps of:
(a) allowing said wadded mass to adsorb a portion of said liquid
hydrocarbon upon surfaces of the relatively shorter fibers and the
relatively longer fibers; and (b) allowing said wadded mass to
absorb a portion of said liquid hydrocarbon within said substantial
volume of internal interstices.
61. The method of claim 57, wherein said synthetic fabric scrap
comprises delustered fibers.
62. The method of claim 61, wherein said delustered fibers were
delustered with titanium dioxide.
63. The method of claim 57, wherein the step of shredding said mass
of synthetic fibers is carried out so as to produce a majority of
said synthetic fibers having a length in the range of from about 10
mm to about 20 mm, and a minority of said synthetic fibers having a
length in the range of from about 75 mm to about 100 mm.
64. The method of claim 57, further comprising the steps of
segregating synthetic fabric scrap to provide a mass of synthetic
fabric scrap comprising substantially more synthetic fiber than
natural fiber; and then shredding only said mass of synthetic
fabric scrap.
65. The method of claim 64, wherein the step of segregating
synthetic fabric scrap provides a mass of synthetic fabric scrap
comprising about 90% synthetic fiber.
66. The method of claim 57, wherein the step of shredding comprises
the step of controlling a processing rate while shredding the
fabric scrap to achieve a desired reduction of fabric scrap into
fiber.
67. The method of claim 57, wherein the step of shredding comprises
the step of reducing an amount of flags present in the fiber being
generated to a desired level.
68. The method of claim 57, wherein the step of shredding comprises
the step of adjusting a height between a table on which the
synthetic fabric scrap is disposed and a cutting drum employed to
shred the synthetic fabric scrap.
69. The method of claim 57, wherein the step of shredding comprises
the step of adjusting a height between a table on which the
synthetic fabric scrap is disposed and a pinning drum employed to
shred the synthetic fabric scrap.
70. The method of claim 57, further comprising the step of
segregating synthetic fabric scrap to remove larger pieces of
synthetic fabric scrap, and then shredding only a remaining mass of
the synthetic fabric scrap.
71. A method for removing liquid hydrocarbon from a surface
contaminated with the liquid hydrocarbon, comprising the steps of:
(a) providing a delustered synthetic fiber based sorbent; (b)
collecting the liquid hydrocarbon by: (i) bringing said delustered
synthetic fiber based sorbent into contact with the liquid
hydrocarbon; (ii) allowing the delustered synthetic fiber based
sorbent to adsorb the liquid hydrocarbon from the contaminated
surface, adsorbed hydrocarbons accumulating upon a plurality of
rough, delustered surfaces of said delustered synthetic fiber based
sorbent; and (c) mechanically removing said delustered synthetic
fiber based sorbent from the contaminated surface.
72. A method for removing an organic liquid from a surface
contaminated with the organic liquid, comprising the steps of: (a)
providing a delustered synthetic fiber based sorbent (b) collecting
the liquid hydrocarbon by: (i) bringing said delustered synthetic
fiber based sorbent into contact with the organic liquid; (ii)
allowing the delustered synthetic fiber based sorbent to adsorb the
organic liquid from the contaminated surface, adsorbed organic
liquid accumulating upon a plurality of rough, delustered surfaces
of said delustered synthetic fiber based sorbent; and (c)
mechanically removing said delustered synthetic fiber based sorbent
from the contaminated surface.
73. A delustered fiber sorbent suitable for adsorbing an organic
liquid, said delustered fiber sorbent comprising a plurality of
delustered hydrophobic and lipophilic fibers.
74. The delustered fiber sorbent of claim 73, wherein said
plurality of delustered hydrophobic and lipophilic fibers comprise:
(a) a plurality of relatively shorter hydrophobic and lipophilic
fibers, a majority of said plurality of relatively shorter
hydrophobic and lipophilic fibers having lengths ranging from about
10 mm to about 20 mm; and (b) a plurality of relatively longer
hydrophobic and lipophilic fibers, a majority of said plurality of
relatively longer hydrophobic and lipophilic fibers having lengths
ranging from about 70 mm to about 90 mm, said relatively longer
hydrophobic and lipophilic fibers binding said plurality of
relatively shorter hydrophobic and lipophilic fibers and said
plurality of relatively longer hydrophobic and lipophilic fibers
into a wadded mass.
75. The delustered fiber sorbent of claim 73, wherein said
plurality of delustered hydrophobic and lipophilic fibers comprise:
(a) a majority of relatively shorter hydrophobic and lipophilic
fibers; and (b) a minority of relatively longer hydrophobic and
lipophilic fibers.
76. The delustered fiber sorbent of claim 73, further comprising a
plurality of hydrophilic fibers, such that said delustered fiber
sorbent comprises substantially more delustered hydrophobic and
lipophilic fibers than hydrophilic fibers.
77. The delustered fiber sorbent of claim 73, wherein said
delustered hydrophobic and lipophilic fibers have been delustered
with titanium dioxide.
78. The delustered fiber sorbent of claim 73, wherein said
delustered hydrophobic and lipophilic fibers are encased in a
porous, encapsulating envelope.
79. The delustered fiber sorbent of claim 78, wherein said porous,
encapsulating envelope comprises at least one of a boom, a pillow,
a sock, a quilted blanket and a filter unit.
80. The delustered fiber sorbent of claim 79, wherein said quilted
blanket comprises one of baffles and channels to enhance a wadded
mass configuration of said delustered hydrophobic and lipophilic
fibers.
81. The delustered fiber sorbent of claim 73, wherein said
delustered hydrophobic and lipophilic fibers are formed into at
least one of a sorbent pad and a sorbent blanket.
82. The delustered fiber sorbent of claim 73, wherein said
delustered hydrophobic and lipophilic fibers are needle punched to
form at least one of a sorbent pad and a sorbent blanket.
83. A delustered fiber filter suitable for removing an organic
liquid from a mass of water, said delustered fiber filter
comprising a plurality of delustered hydrophobic and lipophilic
fibers.
84. The delustered fiber filter of claim 83, wherein said plurality
of delustered hydrophobic and lipophilic fibers comprise: (a) a
majority of relatively shorter hydrophobic and lipophilic fibers;
and (b) a minority of relatively longer hydrophobic and lipophilic
fibers.
85. The delustered fiber filter of claim 83, further comprising a
plurality of hydrophilic fibers, such that said delustered fiber
filter comprises substantially more delustered hydrophobic and
lipophilic fibers than hydrophilic fibers.
86. The delustered fiber filter of claim 83, wherein said
delustered fiber filter does not substantially impede a flow of
water through said delustered fiber filter.
87. A method for removing at least one of an organic liquid and a
liquid hydrocarbon from a surface of a body of water contaminated
with one of the organic liquid and liquid hydrocarbon, comprising
the steps of: (a) providing a hydrophobic and lipophilic sorbent
product that is encased in a porous encapsulating boom, said
hydrophobic and lipophilic sorbent product comprising a plurality
of delustered hydrophobic and lipophilic fibers; (b) collecting the
liquid hydrocarbon by: (i) encircling a portion of the surface of
the body of water with the sorbent filled porous encapsulating
boom, said portion encompassing all of the surface of the body of
water that is contaminated; (ii) allowing the sorbent filled porous
encapsulating boom to sorb at least a portion of said one of the
organic liquid and the liquid hydrocarbon from the surface of said
body of water; (iii) removing a first portion of said sorbent
filled porous encapsulating boom from the surface of said body of
water, thereby reducing an area of the body of water that is
encircled by the sorbent filled porous encapsulating boom; (iv)
pressing the first portion of the sorbent filled porous
encapsulating boom that was removed from the surface of said body
of water to recover the at least one of an organic liquid and a
liquid hydrocarbon, and thus regenerating the sorbency of the first
portion of the sorbent filled porous encapsulating boom; (v)
returning the regenerated first portion of the sorbent filled
porous encapsulating boom to the surface of the water to absorb
more of the at least one of the organic liquid and the liquid
hydrocarbon; and (vi) repeating steps (iii)-(v) until the at least
one of the organic liquid and the liquid hydrocarbon is
substantially removed from the surface of said body of water.
Description
FIELD OF THE INVENTION
[0001] The present invention is generally directed to a delustered
fiber sorbent and a method of using the delustered fiber sorbent in
the removal of hydrocarbon products from a contaminated material,
and more specifically, to the removal of hydrocarbon products
contaminating the surface of an aqueous medium, by employing a
wadded mass of delustered hydrophobic and lipophilic fibers that
are placed in contact with the contaminated surface so as to sorb
the hydrocarbon products.
BACKGROUND OF THE INVENTION
[0002] The widespread use of petroleum products is accompanied by
the almost statistical certainty that accidents involving the
release of petroleum products into the environment will occur. In
recognition of the deleterious effects such spills can have on the
environment, many governmental agencies have drafted regulations
mandating that spill response equipment, including sorbent
material, be readily available to contain and collect the spilled
material, to minimize the deleterious environmental effects of the
petroleum products.
[0003] Due to increasing globalization, many nations are involved
in transporting extremely large volumes of raw petroleum and
petroleum products in tanker ships via waterways, such as lakes,
rivers, and, oceans and in tanker vehicles or railcars that travel
adjacent to waterways. Accidents involving large volumes of
petroleum, such as the Exxon Valdez incident in Alaska, have
generated tremendous concern among the public. In response to such
incidents, various governmental agencies have adopted strict spill
response regulations to prevent, or at least minimize, the damage
from a future large scale spill on waterways. Such regulations
often provide for the creation of spill response teams that are
required to stockpile large quantities of sorbent material at
locations that are associated with high traffic of large volumes of
petroleum products. In recognition of the need for sufficient
quantities of sorbent material to be readily available at many
different locations, it would be desirable to provide an efficient,
inexpensive, and lightweight sorbent product that can be used to
remove petroleum and other hydrocarbon products from contaminated
surfaces, including the surface of a body of water.
[0004] The prior art includes many different types of sorbent
products. Sorbents work either by absorption, adsorption, or both.
Absorption is a process in which a material is taken in through
pores or interstices of another material, while adsorption is a
process in which a material is accumulated on the surface of a
solid or liquid. In general, sorbents that function via both
absorption and adsorption tend to be more effective in enabling a
petroleum or other hydrocarbon spilled on a surface to be collected
and removed. It would therefore be desirable to provide a sorbent
that is sufficiently economical and environmentally friendly to be
used on the surface of a body of water, and which both adsorbs and
absorbs petroleum and other hydrocarbon products.
[0005] The prior art recognizes that an effective sorbent material
should have a high affinity for sorbing the target material to be
collected and removed, and that the sorbent should preferably sorb
a relatively large amount of the target material per unit weight of
the sorbent. Effective sorbents tend to have a relatively great
surface area, so as to encourage contact of the sorbent with the
target material. With respect to sorbents employed to recover
hydrocarbons from the surface of a body of water, a low specific
gravity ensures that the sorbent will float on the water surface,
both before and after hydrocarbons have been sorbed.
[0006] U.S. Pat. No. 5,304,311 discloses an elastomeric
ethylene/alpha-olefin copolymer, optionally copolymerized with a
diene, that can be applied in a granular subdivided form. After
absorbing the hydrocarbon product, the sorbent forms a jelly-like,
homogeneous mass, which can then be removed by conventional
mechanical means. The jelly-like mass is cohesive, and modest wave
action will not disperse the sorbent beyond a desired area of
treatment. While effective, such a material requires a finite
contact period to transition from the granular state to the
jelly-like mass. Sorbents such as that disclosed in the
above-referenced patent are often referred to as solidifiers, as
they change oil from a liquid to a solid. Unlike sorbents,
solidifiers do not release solidified oils under pressure, ensuring
that the "dripping-sponge" effect is eliminated, which in some
situations may be desirable. However, there are many instances in
which it may be desirable to recover and recycle any petroleum
product that has been picked up by a sorbent. A French study of oil
solidifying agents concluded that the following problems are
associated with solidifiers: (1) the reaction of cross-linkers (in
the solidifier) with portions of oil that are in direct contact
results in non-uniform solidification; (2) the non-selective nature
of cross-linkers that will solidify anything that contains
hydrocarbons, including weeds and other organic matters; (3)
mechanical difficulty in removing a solidified spill, since it
cannot be pumped; and, (4) the large amount of solidifier that is
required to cross-link and solidify an oil spill. Finally, due
primarily to the cost of the ingredients, such as the cross-linkers
required to facilitate the solidifying reaction, solidifiers such
as that disclosed in the above-referenced patent tend to be
somewhat expensive. It would be desirable to provide a more rapidly
acting sorbent material, which is less costly to produce, requires
a relatively small volume of sorbent to be employed, and which can
be processed to recover sorbed hydrocarbons if desired.
[0007] In addition to granular solidifying sorbents, the prior art
also discloses the use of polymeric fibers and expanded polymeric
foams to sorb petroleum products. U.S. Pat. No. 5,407,575 describes
a relatively small two-part sorbent pad having a flat, chemically
treated polyethylene foam inner core completely surrounded by a
flexible, durable, chemically treated polypropylene fabric cover.
The sorbent pad is intended to float on top of petroleum covered
water and to soak up the petroleum or oil and hold it within the
inner core until it can be removed by squeezing the sorbent pad
between rollers, thereby recovering the oil for storage in a
container. The sorbent pad can then be returned to the water to
pick up more petroleum. The sorbent pad is chemically treated to
increase the pad's ability to attract and hold oil by both
adsorption and absorption and to further increase the pad's ability
to repel water. This treatment necessitates extra processing in the
manufacture of the sorbent, thereby increasing its cost. While the
sorbent pad is useful, it would be desirable to provide a lower
cost sorbent that are not in a pad configuration and thus can be
carried or stored in large quantities as needed, in order to be
able to treat massive oil spills, such as those associated with an
oil tanker running aground and breaking apart.
[0008] In addition to employing polymeric granules and foams, the
prior art also discloses using polymeric fibers as a petroleum
sorbent. Many patents disclose various filters for either cleaning
oil, or removing oil from water, which include polymeric fibers.
Fibers that have little cotton or cellulose content are
hydrophobic, and have a high affinity for petroleum. Examples of
patents that disclose the use of polymeric fibers in a filter
include U.S. Pat. No. 4,329,226, which discloses a filter apparatus
for reconditioning oil and uses cotton fibers, polyester fibers,
and wood (specifically aspen) fibers to filter dirty oil. U.S. Pat.
No. 4,707,269 describes a non-woven hydrophobic fabric used to
separate oil and water mixtures, and U.S. Pat. No. 5,855,784
describes a sheet filter formed of thermally bonded polymer fibers.
U.S. Pat. No. 5,993,675 describes a fuel filter that includes
polymeric micro-fibers to remove water from a hydrocarbon fuel.
[0009] Regulatory and governmental agencies are increasingly
focusing on the use of environmental friendly products. In
addition, there is a general preference by many such agencies to
purchase recycled products over new products, whenever possible.
Thus, it would be desirable to provide a sorbent that can be
produced from scrap or recycled materials, with minimal required
processing.
[0010] In addition to using polymeric fibers for filters, such
fibers have also been employed as sorbents. U.S. Pat. No. 5,080,956
describes a laminate mat designed to be placed underneath machinery
to catch oil drips machinery and comprising flow directing means,
and an adsorbent layer made from a mat of OLEFIN.TM. fiber.
Polymeric fibers have also been used as fillers for booms and
pillows, most often in the form of a mass of spun fiber inserted
into a boom or pillow. While these sorbent products are functional,
they employ virgin fiber, and thus offer no advantage for those
seeking to use a recycled product. It would therefore be desirable
to provide a hydrophobic and lipophilic fiber-based sorbent product
that can be produced more economically than currently available
sorbents, and which can be made from recycled material. It should
be noted that particularly in respect to recycled fibers, there is
a perception that recycled fibers are generally poorer in quality
than virgin fiber. It would therefore be desirable to provide a
recycled fiber based sorbent that is as effective as, if not more
effective than, virgin fiber-based sorbents.
SUMMARY OF THE INVENTION
[0011] The present invention preferably employs synthetic fiber
waste that would otherwise be disposed of in a landfill or other
waste facility. While virgin synthetic fiber could be employed in
the present invention, additional processing steps would be
required to achieve the greater sorption efficiency that are
provided by waste fibers from the textile industry. Note that
synthetic fibers are naturally hydrophobic and lipophilic (i.e.,
they exhibit a natural affinity to sorb hydrocarbons, while at the
same time they do not sorb water, making them well suited for
sorbing hydrocarbons from the surface of a body of water).
Accordingly, synthetic fibers are well suited for use as sorbents.
Via empirical testing and analysis, applicants have determined that
enhanced sorption efficiency can be obtained relative to other
virgin polymer-based sorbents by controlling the fiber lengths and
by using specially treated fibers.
[0012] Traditional virgin synthetic fibers have good adsorption
properties with respect to hydrocarbons. Depending on the physical
state or configuration of the fibers, virgin synthetic fiber-based
sorbents may also have good absorbent properties. Adsorption is
based on the attraction of material to the surface of a sorbent.
Because of the natural chemical affinity between petroleum products
and synthetic fibers, generally most synthetic fibers are
reasonably effective at adsorbing hydrocarbons. In contrast,
absorption is more a function of the physical state or
configuration of the sorbent, because absorption involves the
uptake of a material into a plurality of interstitial spaces within
a matrix formed by the sorbent. A single, generally elongate
extending fiber has no interstitial spaces (unless that fiber has
been specially treated to enable the interior of the fiber to be
accessible to a material, such as a dye), and cannot provide
absorption of a material. However, a mass of fibers form a
plurality of interstitial spaces in which absorption occurs. Such a
mass can be beneficially employed as a sorbent or filter media.
[0013] Applicants have discovered that a mass of hydrophobic and
lipophilic fibers having a specific range of lengths, when mixed
together to form a matrix, have a greatly enhanced absorbency and
serve as a very efficient sorbent. This matrix of fiber having a
preferred range of lengths are referred to herein and in the claims
that follow, as a "wadded mass," or alternatively, as a "wad." A
wad preferably includes a substantial majority of shorter fibers
and a minority of longer fibers (i.e., relative to a mid-length
within the specific range of lengths). The long fibers act as a
natural binder to give the resulting wad cohesiveness. The
cohesiveness is sufficient so that the wad does not need to be
encapsulated in a boom when used in treating oil spills. In
moderate marine conditions, even normal wave action will not unduly
disperse the wadded mass of sorbent, which is in sharp contrast to
granular sorbents and non-wadded fiber based sorbents that
typically require the use of encapsulating booms so that the
respective sorbents are not unduly dispersed.
[0014] Empirical testing has determined that fiber lengths ranging
from about 5 mm to about 100 mm are most preferred. A substantial
majority of the fibers preferably range from about 5 mm to about 55
mm in length, and most preferably, about 70% of the fibers fall
into the aforementioned range of length. The length of a minority
of the fibers is in the range of from about 60 mm to about 100 mm
in length, and most preferably, less than about 30% of the fibers
are in this range. Regardless of the specific range employed, a
substantial majority of the fibers must be relatively short to
provide the desired large surface area, and the desired plurality
of interstitial volumes. Also, regardless of the specific range of
lengths of the fibers, sufficient relatively long fibers are
required to enable the wadded mass to achieve a cohesiveness that
resists dispersing the fibers when the wadded mass is exposed to a
moderate wave action. Such dispersion is not desired, as widely
dispersed sorbents are much more difficult to recover.
[0015] The ratio of short fibers to long fibers in the wadded mass
is important in providing a high efficiency sorbent and filter
media. A majority of short fibers increase sorbency by increasing
the total surface area of the sorbent and by ensuring that the
wadded mass includes a larger volume of interstitial spaces for
absorption of a material. However, if only short fiber lengths are
employed, the resulting mass of short fibers will be too easily
dispersed by wind or wave action, and very little interstitial
spaces will be available for absorption of hydrocarbons. Thus, a
mass of only the short fibers would be difficult to recover and
would be a less efficient sorbent, as very little absorption would
take place. The only mechanism available for removing hydrocarbons
in such a dispersed mass of only short fibers would be adsorption.
Sufficient long fibers must be included to enable the wadded mass
to be achieved, in accord with the present invention.
[0016] It has also been empirically determined that delustered
synthetic fibers are more efficient sorbents than synthetic fibers
that have not been delustered. Normally, virgin synthetic fibers
are delustered when the fibers are to be used in fabrics. The
delustering removes the inherent shininess of a synthetic fiber.
Sometimes, a high luster in textiles is considered by consumers to
look "cheap," so a low-luster finish will enhance the richness of a
particular fabric or carpeting. Because this is an aesthetic
concern, as opposed to a functional concern, virgin synthetic
fibers employed for sorbents are not delustered. Empirical results
indicate that sorption by the delustered synthetic fibers of the
present invention occurs extremely rapidly. As will be discussed in
detail in the examples provided below, under controlled conditions,
delustered synthetic fibers sorbed 9.5 times their own weight of
oil in only about 10 seconds.
[0017] The delustering process appears to enhance the sorbent
effectiveness of a fiber in several ways. First, the delustering
process works by "scuffing" the surface of individual fibers, to
reduce their sheen. This scuffing step results in rough fiber
surfaces, and an individual fiber with a rough surface will have
significantly more surface area than a fiber of the same size that
has a smooth (or lustrous) surface. The increased surface area not
only increases adsorption per fiber, but the rough surface of the
fibers also increases the amount of interstitial volume available
for absorption. The rough surface provides fiber-to-fiber traction,
which further enhances the ability of a plurality of fibers to
cohesively join together in the wadded mass described above. As
indicated above, the wadded mass configuration provides significant
interstitial volume that enhances absorption. The delustering
process substantially enhances the sorbency of synthetic fibers,
and it is preferable to employ a wadded mass of delustered
hydrophobic and lipophilic fibers for the present invention. A
common method of delustering fibers is to treat synthetic fibers
with titanium dioxide.
[0018] Yet another aspect of the present invention is directed to a
method of recycling waste fiber scrap into a sorbent product. Whole
cloth is often recycled into other cloth applications. A large
percentage of the used clothing that is recycled is reused as
clothing and is often shipped overseas for use in third-world
countries. A surprisingly efficient collection and distribution
system enables a used, but still serviceable pair of pants from the
United States to be shipped to a third-world country and sold at a
cost significantly lower than a locally produced garment. Cloth is
also recycled into wiping rags for industry and engineering
applications. Almost 50% of recycled textiles are recycled back
into clothing. About 20% become wiping and polishing cloths, and
another 25% are regenerated--converted back into fiber. Little of
this fiber (referred to as "shoddy") is currently being re-spun
into new textiles, because such regenerated fibers are weaker than
virgin fibers, resulting in a lower quality fabric. Instead, shoddy
is often used in lower value applications such as for furniture
stuffing or insulation in vehicles. However, the demand for shoddy,
particularly shoddy that is primarily synthetic fiber (known as
"poly shoddy"), is generally significantly less than the available
supply. In many areas of the country, rag mills are forced to
dispose of poly shoddy in municipal landfills, at costs of up to
five cents a pound.
[0019] In most of the conventional uses of shoddy, fiber length and
its affect on the resulting matrix of the shredded fabric is not
critical. Indeed, most shoddy is pressed into felt or other
non-woven fabric, often after being impregnated with binders and
adhesives. Generally, the fabric is processed to remove buttons and
zippers, and the fabric is then shredded to a more or less fibrous
state. In one aspect of the present invention, this traditionally
processed poly shoddy can be used in encapsulating booms and
pillows as a sorbent material. The fibers in the poly shoddy will
already be substantially delustered, as most fabrics are made from
delustered fiber. However, it is anticipated, and empirical testing
has verified this to be true, that the sorbent efficiency of poly
shoddy can be improved by applying more stringent processing steps
than are normally required for generating shoddy.
[0020] One aspect of the present invention calls for manipulating
the shredding process to control the fiber lengths achieved. As
noted above, the majority of the fibers are preferably relatively
short, from about 5 mm to about 50 mm in length. Preferably, more
than about 70% of the fibers are within this range. A minority of
the fibers must be relatively long, to enable the wadded mass
described above to be achieved. The wadded mass configuration
includes so much interstitial space that fibers in the wadded mass
configuration are significantly more sorbent than the same fibers
in a more planar configuration, such as a mat, due to the
absorption occurring in the interstitial spaces. Preferably the
relatively long fibers are from about 60 mm to about 100 mm in
length, and comprise less than about 30% of the fibers.
[0021] The exact method used for controlling fiber length is a
function of the equipment employed to process the synthetic fabric.
In general, additional processing time will be required to achieve
the desired dimensions. Note that for traditional uses of shoddy,
it is preferable to minimize processing time, even if not all the
fabric is completely reduced to fiber. In the present invention,
the more complete the transformation from fabric to fiber, the more
efficient the sorbent will be. It should also be noted that up to
approximately ten percent by weight of the wadded mass can comprise
non-synthetic fiber, such as cotton and cellulose fibers, without
reducing the sorbent power of a wadded mass. Indeed, empirical
testing has determined that the presence of small amounts of
hydrophilic fibers is actually beneficial. Thus, an additional
requirement with respect to the conventional poly shoddy
manufacturing process is to presort the material being processed,
to ensure that the desired blend or ratio of synthetic to
non-synthetic fiber is achieved. It has been determined that up to
10% non-synthetic fiber is desirable. The presorting will be
accomplished by hand, by technicians who can generally determine
whether a textile is synthetic or non-synthetic by touch.
Preferably the presorting will also be employed to remove
undesirable non-synthetic textiles, such as vinyl textiles, or
bulky textiles, such as sleeping bags, from the textiles that will
be shredded.
[0022] One characteristic of conventionally processed poly shoddy
is the presence of "flags" or "bits" in the final product. These
flags and bits, generally quadrilateral in shape, represent
portions of a textile item that have been reduced in size, but not
to the fiber level. Such flags or bits can range in size from
relatively small (fractions of an inch in dimension) to relatively
large (over a foot in dimension), and their presence generally does
not interfere with conventional uses of shoddy (for example, a
furniture stuffing or to produce carpet pads). However, in the
present invention, the presence of such flags reduces the amount of
fiber present in a wadded mass, thereby reducing the sorbency of
the product. Accordingly, it is desirable for the conventional poly
shoddy producing process to be controlled to reduce the amount of
flags or bits present in the final product.
[0023] A final aspect of the present invention is directed toward
the use of a mass of delustered hydrophobic and lipophilic fibers
as a filter media. In one embodiment, the mass of delustered
hydrophobic and lipophilic fibers are processed into the previously
described wadded mass by controlling the relative length of
individual fibers. In another embodiment, the mass of delustered
hydrophobic and lipophilic fibers is configured into a non-woven
pad that is used as a filter. While such a non-woven pad lacks the
extensive interstitial volume present in a wadded mass, the
delustered fibers still provide an excellent filter media. When the
delustered hydrophobic and lipophilic fibers are produced from
textile waste, such pads can be produced at a low cost and can be
employed as filter media or sorbents. Small pads can be fabricated
for use with small spills, or large pads, referred to as blankets,
can also be produced for use in cleaning up larger spills of
petroleum products.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0024] The foregoing aspects and many of the attendant advantages
of this invention will become more readily appreciated as the same
becomes better understood by reference to the following detailed
description, when taken in conjunction with the accompanying
drawings, wherein:
[0025] FIG. 1A is a schematic view of a relatively short
hydrophobic and lipophilic fiber that comprises the majority of a
sorbent wad of fibers in accord with the present invention;
[0026] FIG. 1B is a schematic view of a relatively long hydrophobic
and lipophilic fiber that comprises the minority of a sorbent wad
of fibers in accord with the present invention;
[0027] FIG. 2A is a schematic view of a relatively wide hydrophobic
and lipophilic fiber that comprises the majority of a sorbent wad
of fibers in accord with the present invention;
[0028] FIG. 2A is a schematic view of a relatively thin hydrophobic
and lipophilic fiber that comprises the minority of a sorbent wad
of fibers in accord with the present invention;
[0029] FIG. 3 is a schematic view of a fiber that has been
delustered with titanium dioxide;
[0030] FIG. 4 is a schematic cross-sectional view of a fiber that
has been delustered with titanium dioxide, clearly showing that the
titanium dioxide particles are incorporated into the fiber matrix,
rather than merely being dispersed on the surfaces of the
fiber;
[0031] FIG. 5 is a schematic view of a plurality of relatively long
hydrophobic and lipophilic fibers intermingled with a plurality of
relatively short hydrophobic and lipophilic fibers to form a
sorbent wadded mass in accord with the present invention;
[0032] FIG. 6 is an enlarged view of a portion of the schematic
view of FIG. 3, illustrating adsorption on the delustered surfaces
of both the plurality of relatively long hydrophobic and lipophilic
fibers and the plurality of relatively short hydrophobic and
lipophilic fibers, as well as absorption at a plurality of
interstitial spaces within the wad of sorbent;
[0033] FIG. 7 is a schematic view of a bale of the wadded sorbent
of FIG. 3 being pushed into a body of water proximate to an oil
spill;
[0034] FIG. 8 is a schematic the wadded sorbent of FIG. 3 being
used to fill an encapsulating boom;
[0035] FIG. 9 is a graphical comparison of the sorbent properties
of a wadded mass in accord with the present invention, and a prior
art sorbent, and
[0036] FIG. 10 is a graphical illustration of the sorbency of a
wadded mass over time.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0037] FIGS. 1A and 1B illustrate schematic representations of a
relatively short fiber 12 and a relatively long fiber 14,
pluralities of each of which are required in the sorbent wad of the
present invention. The exact proportions of the individual fibers
are not critical, though a majority of the fibers need to be
relatively short, while only a minority of the fibers should be
relatively long. The relatively short fibers provide a great deal
of surface area, while the relatively long fibers help bind the
relatively short fibers and relatively long fibers together into a
wadded mass. In one preferred embodiment, the relatively short
fibers are on the order of from about 5 mm to about 15 mm in
length, while the relatively long fibers are on the order of from
about 85 mm to about 100 mm in length. Such an embodiment also
includes a plurality a fibers of intermediate length, ranging from
about 15 mm to about 85 mm in length. Detailed examples of the
fiber lengths of this preferred embodiment are discussed below.
[0038] A mixture of different fiber types is acceptable. The
majority of the fibers must be hydrophobic and lipophilic (i.e.,
capable of adsorbing hydrocarbon products). Synthetic fibers such
as polyester, nylon, acrylic, and triacetate can be beneficially
employed as the majority of fibers. In a preferred embodiment,
approximately 70% of the fibers are polyester, approximately 20% of
the fibers are nylon, less than about 2% of the fibers are acrylic,
and less than about 1% of the fibers are triacetate. It is
anticipated that these relative percentages can vary considerably
and still provide a useful sorbent, as each of the fibers
individually meet the criteria of being hydrophobic and lipophilic
(capable of sorbing a hydrocarbon).
[0039] FIGS. 2A and 2B illustrate schematic representations of a
relatively thick fiber 22 and a relatively thin fiber 24. In a
preferred embodiment of the present invention, a majority of the
fibers are relatively thick, while a minority of the fibers are
relatively thin. Again, the exact proportions of the individual
fibers are not critical. In the preferred embodiment of the
invention noted above, a majority of the fibers are relatively
thick, while a minority of the fibers are relatively thin. The
relatively thick fibers are on the order of about 45 .mu.m in
diameter, while the relatively thin fibers are on the order of
about 15 .mu.m in diameter. With respect to the length of fibers,
the present invention requires that a substantial majority of the
fibers be relatively short, while only a minority of fibers are
relatively long. In this embodiment and all others, the terms
"long" and "short" generally relate to a midpoint in the specific
range of lengths of the fibers that are used. Such a mixture of
fiber lengths enhances the sorbency of the resulting wad of fiber.
With respect to the relative diameters of the individual fibers, it
is anticipated that the diameters of the individual fibers require
significantly less control, and do not significantly affect the
sorbency of the wad. A mixture of different fiber diameters is
expected to somewhat enhance the cohesiveness of a wad of fibers
having a plurality of lengths, but to a lesser degree than the
mixture of different fiber lengths. It should also be noted that
fiber length is a function of processing, in that fibers can be
processed to achieve a specific desired range of lengths. With
respect to diameters, the diameter of a particular fiber is
essentially a function of the specific material comprising the
fiber. For example, the polyester fibers obtained from processing
fabric waste into fibers, in accord with a preferred method of
producing the sorbent of the present invention (discussed in detail
below), are generally about 45 .mu.m in diameter, while nylon
fibers from the same source generally about 15 .mu.m in diameter.
Thus, relative diameters within the wadded mass can be varied by
varying the mixtures of fibers employed.
[0040] It has been determined that delustering enhances the
sorbency of synthetic fibers, which inherently have a sheen due to
their smooth outer surface. The delustering effect has been
empirically determined, and it is believed that at least two
mechanisms are responsible for the increase in sorbency for
delustered fibers. First, delustering significantly roughens the
surface of individual fibers, significantly increasing the surface
area of each individual fiber, and thus enabling a greater amount
of adsorption per fiber. Secondly, it should be noted that rough
surfaces of the individual fibers, in combination with the mix of
short and long fiber lengths, enable a surprisingly cohesive wad of
fiber sorbent to be achieved. The rough surfaces provide
fiber-to-fiber traction, enabling adjacent fibers to better adhere
to one another. The mix of a minor portion of relatively long
fibers to a majority of relatively short fibers ensures that
sufficient relatively long fibers are present to help bind the
wadded mass together without the need for binding agents normally
employed to bind amorphous masses of fiber together. This wadded
mass configuration ensures that a significant amount of
interstitial volume is available for absorption. Thus delustering
is believed to enhance sorption by providing more sites for both
adsorption and absorption to occur. While the wadded mass of the
present invention, with its majority of relatively short fibers
providing significant surface area, begins to sorb hydrocarbon
products immediately upon contact, it is anticipated that it will
be preferred to leave the wadded mass in contact with the
hydrocarbon product to be sorbed for a reasonable length of time
(for example, 10 minutes or more). While the process of adsorbing
hydrocarbon products onto surfaces of the relatively short fibers,
and the surfaces of relatively long fibers occurs rapidly, the
process of absorption is expected to require more time. Absorption
will occur in interstitial regions within the wadded mass.
Delustering using titanium dioxide is a preferred technique, since
it adds a significant amount of surface area to each individual
fiber surface, as well as helping the fibers maintain a wadded mass
configuration in which a plurality of interstitial volumes are
available for absorption. It is anticipated that leaving the
sorbent wadded mass of the present invention in contact with
hydrocarbon products to be sorbed for additional time will enable
hydrocarbon products to be more fully absorbed into these
interstitial volumes within the wadded mass of delustered
fibers.
[0041] It should be noted that several different types of
delustering processes are known in the art. One popular technique
for reducing the luster of synthetic fibers that are obtained by
melt-spinning is to introduce an inorganic substance such as silica
or titanium oxide in the starting material (the base synthetic
resin) before that material is subjected to melt-spinning. The
inorganic substance becomes substantially uniformly distributed
throughout the resulting fiber, appearing on both the exterior
surface and interior of the fiber. FIGS. 3 and 4 show a fiber 15
that incorporates titanium dioxide particles 17 in its structure.
Note that titanium dioxide particles 17 are not merely coated onto
the surface of fiber 15, but are actually dispersed throughout the
interior of fiber 15 as well. It should be noted that titanium
dioxide is inert and non toxic, and thus, its presence in a sorbent
product does not pose any environmental or health risks.
[0042] Delustering with titanium dioxide appears to offer several
advantages. Titanium dioxide is a hydrophobic material, and its
incorporation into a synthetic fiber is consistent with the desired
goal of providing hydrophobic fibers. Furthermore, the
incorporation of micro-crystalline titanium dioxide into a
synthetic fiber substantially increases the surface area of each
fiber, thereby substantially increasing the adsorbency of each
fiber. Also, the relatively rough surface produces significant
friction. Note that synthetic fibers that are not delustered are
"slippery," and that in a mass of such fibers, cohesiveness is
likely to be poor as individual fibers are prone to slip past each
other. The titanium dioxide provides friction, so that individual
fibers are much less likely to slip past one another, enabling the
wadded mass of the present invention to be achieved.
[0043] Other delustering methods involve covering the surface of
the fibers with a resin having a low refractive index, or
developing uneven patterns in the surface of the fibers. For
example, Japanese Patent Publication No. Sho 43-22349 discloses a
method of subjecting a polyamide fiber to an inorganic acid to
erode or etch the surface of the fiber. It is anticipated that
these other methods of delustering fibers are less preferred for
producing a sorbent fiber than the technique of delustering using a
mineral such as titanium dioxide. Coating a fiber with a polymer
that has a low refractive index will not produce an increased
surface area on the fiber, or enhance fiber-to-fiber traction.
Etching the surface of a fiber will produce an increased surface
area on the fiber, but is not likely to enhance fiber-to-fiber
traction. Therefore, delustering with an inorganic chemical such as
titanium dioxide is preferred, particularly because the titanium
dioxide particles significantly increase fiber-to-fiber traction,
and significantly increase overall fiber surface area.
[0044] If virgin fibers are to be used to produce a sorbent in
accord with the present invention, then preferably an inorganic
chemical such as titanium dioxide will be added to the resin before
melt-spinning the fiber. If recycled synthetic textile products are
shredded to generate a fiber sorbent in accord with the present
invention, further treatment with titanium dioxide is not likely to
be required, because the majority of delustered fibers used in the
textile industry are produced using titanium dioxide (or similar
inorganic materials). The reason for the widespread use of the
titanium dioxide based delustering process is that it does not
require an additional processing step to be performed after the
production of the fiber (as is required if the fiber is coated with
a different polymer, or etched with a chemical). The elimination of
an additional processing step increases the efficiency of the
production process, thereby lowering the overall cost of the
product. While it is anticipated that the titanium dioxide
delustering process will be the preferred method of delustering,
due to its current widespread use and relatively low cost, other
delustering processes that similarly increase fiber-to-fiber
traction and significantly increase overall fiber surface area can
also be beneficially employed. A wadded mass 30 in accord with the
present invention is schematically illustrated in FIG. 5. A
plurality of relatively short fibers 12 are intermingled with a
plurality of relatively long fibers 14. As noted above, a minority
of relatively long fibers 14 bind the mass of interleaved fibers
(both long and short) together into the desired cohesive wadded
mass. Without a sufficient amount of relatively long fibers, the
relatively short fibers, even with the fiber to fiber traction
enabled by the delustered fiber surfaces described above, would
tend to disperse due to wind, wave action, or other forces. Such
dispersion might enable the fibers to be blown away from contact
with a spill and will make retrieving the sorbent difficult.
However, using only relatively long fibers would considerably
reduce the surface area associated with the wadded mass. Empirical
testing has confirmed that a high surface area is key to a sorbent
that begins sorbing material very rapidly, as well as being an
important factor in achieving a sorbent that has a high capacity to
absorb hydrocarbons. The examples provided below provide details on
the relative percentages and ranges of different fibers and fiber
lengths associated with a preferred sorbent wadded mass in accord
with the present invention.
[0045] FIG. 6 illustrates how wadded mass 30 provides a sorbent
that exhibits both adsorbent capabilities, as well as absorbent
capabilities. Hydrocarbon products 40 are adsorbed on individual
surfaces of both relatively short fibers 12 and relatively long
fibers 14. Hydrocarbon products 42 are absorbed into interstitial
spaces within wadded mass 30, proximate to locations where
relatively short fibers 12 and relatively long fibers 14 cross each
other.
[0046] FIG. 7 shows a bale of wadded mass 30 being applied to a
body of water 40 contaminated with an oil spill 50. Optionally, the
wadded mass can be compressed before shipment to a site where it is
used and then decompressed prior to spreading the wadded mass on
the surface of the water. The wadded mass can be manually
distributed over the water for a small spill, or can be "blown" on
to the contaminated water surface using an appropriate blower (not
shown) such as the type of blowers used to blow insulation into an
attic. Once the wadded mass has been in contact with the oil slick
for a brief period of time, wadded mass 30 can be mechanically
retrieved. It should be noted that some currently available sorbent
products, particularly solidification agents, require significantly
longer time to reach their full sorbent capacity (up to 24 hours).
The present invention requires only minimal contact time (merely
seconds) to achieve a significant percentage of its total sorbent
capacity. The sorbent product of the present invention will begin
to sorb hydrocarbon products immediately upon contact. As the test
data provided below show, a wadded mass of delustered synthetic
fibers sorbed over 9.5 times its own weight of motor oil in only
about 10 seconds. Peak sorbency occurred in about 60 seconds, with
a sorption efficiency of over 98.5%. Additional contact time does
not appear to lead to greater sorption. It is anticipated that when
used in bulk, the sorbent of the present invention can be removed
just minutes after its application, having sorbed a substantial
mass of petroleum product (and being fully saturated).
[0047] While not shown, the sorbent of the present invention can be
mechanically removed from the surface it was dispersed onto. It is
anticipated that rakes or vacuum type removal equipment can be
employed for this purpose. While very vigorous raking or suction
will overcome the natural cohesiveness of the wadded mass, the
wadded mass will merely fraction into small, still cohesive masses.
Separating a wadded mass into smaller fragments will not destroy
the cohesiveness of the smaller fragments. It is anticipated that
wadded masses can be provided in bulk containers, such as bins, and
that the contents of one or more bins can be applied with a blower
unit, as noted above, to quickly apply the sorbent wadding to a
relatively large area, which will be a distinct advantage in
responding to large-scale spills. It should be noted that federal
regulations pertaining to sorbents used in U.S. waters prohibit
sorbent products from being employed without an encapsulating
envelope. While the present invention is physically capable of
being utilized as an non encapsulated sorbent that is spread on the
surface of a body of water, when used for cleaning petroleum
product spills from water surfaces in the U.S., the present
invention will likely be encased in an encapsulating envelope, such
as a boom, sock or pillow. Such a restriction only applies to use
of the material on bodies of water within the U.S.; and non
encapsulated sorbent in accord with the present invention could
readily be used on bodies of water elsewhere in the world, or on
other types of surfaces, such as roadways or floors.
[0048] Once recovered from a surface previously contaminated with a
hydrocarbon spill, the sorbent wadded mass can be pressed to
recover the sorbed hydrocarbons. In an empirical study, over 87% of
motor oil sorbed by a wadded mass in accord with the present
invention was recovered by mechanically pressing the wadded mass.
The wadded mass can then be reused, or disposed of as a waste
product, for example, by incineration. The synthetic fibers (and
trace natural fibers, if present) used to produce the sorbent
wadded mass of the present invention are non toxic materials and
are regularly disposed of in sanitary landfills. Of course, the
ultimate disposal requirements of a wadded mass that has been used
to sorb a hydrocarbon product is a function of the hydrocarbon
product itself, as is true for all sorbent materials. However, the
wadded mass of the present invention can be pressed to reduce the
amount of sorbed material within the spent wadded mass, enabling
the sorbed hydrocarbon product to be recovered and potentially
reducing the disposal cost of the used sorbent.
[0049] The hydrophobic and lipophilic fibers used in the present
invention may vary somewhat in composition. A preferred mixture of
fiber types is provided in the examples below. In general,
synthetic fibers that can be beneficially employed in the present
invention include polyester, nylon, and acrylic. These fibers share
the common characteristic of being light weight, inert and non
toxic. Tests of a preferred fiber mixture disclosed in the examples
below indicate that when incinerated, the residual ash was less
than 1% (.about.0.6%). The U.S. Environmental Protection Agency has
established guidelines for preferred residual ash percentages for
sorbent materials, and those guidelines indicate that up to 2% ash
is acceptable. From a disposal standpoint, the less ash generated
by burning a sorbent material, the better, as the resulting ash
must be hauled to a landfill. Without any hydrocarbon having been
sorbed, the mixture disclosed below has a thermal energy rating of
about 7,600 British Thermal Units (BTU) per pound. In general, the
higher the BTU value of a material, the more likely that material
is usable for energy production. The BTU value of coal varies
substantially, and ranges from 10,000-15,000 BTU/pound. When the
sorbent of the present invention is saturated, or partially
saturated with a hydrocarbon product, the energy value of the
sorbent significantly increases (note the sorbent sorbs up to 20
times its own weight in oil, and oil has a BTU value of
.about.19,000 BTU/pound). Thus, there is potential for disposing of
the used sorbent by incineration that enables energy recovery. U.S.
cement kilns in particular are noted for their use of high BTU
value waste materials as supplementary fuels (the production of
cement is a very energy intensive process).
[0050] It should further be noted that the hydrophobic and
lipophilic fibers used in the present invention are light weight,
and that they sorb up to 20 times their own weight. The mass of
sorbent required to sorb a given volume of hydrocarbon is
significantly less than the mass of some other types of sorbents,
which reduces the final mass and volume of the used sorbent that
must be disposed of, making the disposal cost of the sorbent of the
present invention more economical. FIG. 8 shows the sorbent wadding
of the present invention used as filling in an encapsulating boom
54 of a porous conventional type. While wadded mass 30 can be used
without encapsulating boom 54, it is anticipated that the wadded
mass filling in a boom will provide a popular alternative to virgin
fiber or virgin granular polymer sorbents, especially for use in
U.S. waters. The delustered fibers of the present invention offer
improved sorption over the non-delustered fibers of conventional
sorbents. Furthermore, the delustered fibers of the present
invention can be produced from scrap fabric, providing a recycled
sorbent product that environmentally conscious consumers are
expected to prefer over sorbent products made from virgin material.
Finally, a sorbent in accord with the present invention that is
made from recovered fibers can be produced at a lower cost,
compared to sorbent products made from virgin materials, as the raw
material comprising the recycled fibers is often considered a waste
product that would otherwise be disposed of in a landfill.
[0051] When distributed for use in treating spills, it is
contemplated that the wadded mass in accord with the present
invention can be included in a spill treatment kit that also
provides instructions for its use. The instructions will indicate
that the wadded mass is to be spread over a surface that is
contaminated with a hydrocarbon product, allowed to sorb the
hydrocarbon product, and then mechanically collected and removed
from the surface. Such kits will likely be useful at marinas, where
spills from boats refueling with gasoline or diesel fuel are fairly
common and there is a need for a rapidly deployable sorbent
material to cleanup the spilled fuel.
[0052] It has been noted above that a preferred source of the
fibers for the sorbent wadded mass of the present invention is
textile scrap. It should be noted that virgin material can be
alternatively be employed; however, it is anticipated that textile
and fabric scrap will be a preferred source, both because textile
and fabric scrap have already been delustered, and because textile
and fabric scrap is a lower cost raw material.
[0053] Virgin synthetic fiber can also be delustered and processed
into the relatively short and relatively long fibers of the
specific desired range of lengths required to achieve the sorbent
wadded mass of the present invention. If virgin fibers are
employed, it is preferred that a plurality of different fiber
lengths be provided, rather that providing only shorter fibers of
approximately 10 mm, and longer fibers of approximately 90 mm in
length. It is believed that a mixture of somewhat random lengths,
the majority of which are relatively short, and a minority of which
are relatively long, help achieve a more cohesive wadded mass. Once
the virgin delustered fibers are cut to the desired length, they
must be thoroughly blended to achieve the spatial distribution
needed to form a wadded mass. Casually mixing may not achieve the
desired wadded mass having a plethora of interstitial spaces needed
for efficient absorption to occur. A preferred mixing method is to
vigorously blend the various fiber lengths mechanically, followed
by introducing the blended mixture into a fast moving stream of
air. The air streams adds loft and volume to the mixture, ensuring
that the desired interstitial voids are present.
[0054] When scrap fabric is used as a raw material, the delustering
step is not required. When rag mills process scrap fabric into
recycled fiber, the fabric is first passed though a series of heavy
crushing rollers that break and crush all zippers and buttons. Next
the fabric engages large rotating drums equipped with hundreds of
cutting blades that cut, rend and tear the fabric. Depending on the
type of equipment employed by the rag mill, a second type of drum
equipped with a plurality of pins extending outwardly from the drum
surface may be employed to further reduce the fabric into its
constituent fibers. The blades, or blades and pins, shred the
fabric to a fibrous state. The fibers are then passed though a
blower in which the fibers are blown upward, while the
button/zipper fragments and other non-fiber materials drop down and
are separated from the fibers. Large flags and bits may also drop
out. However, removing all flags and bits would reduce the volume
of material that is processed, so many mills separate the flags and
bits from the button/zipper fragments, and mix them back into the
shredded fiber. The resulting mass of fiber is referred to as
shoddy. Rag mills generally separate synthetic fabric from natural
fibers, and thus generate both poly shoddy and cotton shoddy. The
cotton shoddy is generally more valuable because it is useful in
papermaking. Poly shoddy, when processed into a non-woven mat, is
often used as carpet pads or sound insulation matting in vehicles
and as a filler in the furniture industry, for cushions and futons.
Generally, the supply of poly shoddy exceeds the demand, and the
material must often be discarded in a landfill.
[0055] In one aspect of the present invention, conventionally
processed poly shoddy is used as a sorbent material. The majority
of poly shoddy is delustered synthetic fiber, which as described
above, exhibits adsorbent and absorbent properties with respect to
hydrocarbon products. However, conventionally processed poly shoddy
does not achieve the preferred wadded mass described above, because
in conventional fabric recycling, no control is applied in
maintaining the lengths of the fibers produced. As noted above, to
achieve the desired wadded mass, a majority of the fibers are
preferably relatively short (approximately 10 mm in length), and a
minority of the fibers are preferably relatively long
(approximately 90 mm in length), with a range of different fiber
lengths in between these two extremes. It has been determined that
this composition of fiber lengths consistently achieves a wadded
mass that includes a considerable volume of interstitial spaces,
which significantly enhance the absorbency of the mass of fibers as
compared to the same fibers employed in a non-woven mat.
[0056] One important aspect in achieving the desired wadded mass is
in control of the fiber length, which is not a relevant factor in
the prior uses of poly shoddy. Thus, the conventional process used
for producing poly shoddy must be changed to include the step of
controlling the fiber length. It is anticipated that the step of
controlling the fiber length will be a function of the type of
equipment that a rag mill uses to produce the sorbent fibers. Each
rag mill will have detailed knowledge relating to their specific
type of equipment that will enable them to produce fibers according
to a desired specification. One aspect of the present invention is
providing those desired specifications to a rag mill, to achieve
the desired characteristics for the wadded mass. Empirical tests
have determined that a specification of fiber lengths between 10
mm-90 mm, with a majority of fibers being relatively short, can be
met by rag mills using conventional processing equipment.
[0057] It is anticipated that the rag mills will use a variety of
methods to achieve the above-noted specification. For example, the
rag mills can reduce the speed at which their units normally
operate, to enable them to achieve better control of fiber lengths.
Normally, customers desiring poly shoddy provide no specifications,
and under those circumstances, it is desirable for the rag mill to
process as much material, as fast as possible, to make maximum use
of their capital intensive equipment.
[0058] Another variable that rag mills can control to meet the
above fiber length specification is to the distance from the
cutting and pinning drums to the table or conveyor belt along which
the fabric waste is moving. Normally, this dimension is kept
relatively high to allow bulky items such as polyester jackets or
sleeping bags to pass under the drums. Adjusting this dimension
will effect both the fiber length, and the extent to which a fabric
is reduced into fiber. The rag mill operator may also presort the
material to be shredded, to remove bulky items such as jackets and
sleeping bags, that would require more height between the drum and
table or conveyor belt, to prevent the processing line from being
jammed or disrupted.
[0059] Another option would be to send already shredded material
back through the processing line again, to achieve the desired
shorter fiber lengths. This step of reprocessing the fibers could
be repeated until a majority of the fiber lengths fall in the
desired ranges. Should an insufficient amount of relatively long
fibers be present, then a small portion of less processed (hence
longer) fibers can be added to the relatively short fibers
generated from repeated processing, until the desired ratio of long
to short fibers is achieved. While some processing lines may
require such manipulation, it is anticipated that reducing
processing speed, changing drum heights, and/or preprocess sorting
will be preferred as lower cost techniques to achieve the fiber
length specification. The fibers meeting the length specification
are then mechanically mixed and processed through a blower to
achieve the desired loft.
[0060] As noted above, in conventional shoddy processing, the poly
shoddy product often includes significant amounts of unprocessed
fabric, or patches of fabric that have not been reduced to fiber.
The presence of these patches, referred to as flags (or bits), is
generally not critical to non-sorbent applications for shoddy, and
rag mills typically do not separate the flags from the fibers. In
fact, removing such flags not only increases processing costs, but
also decreases the volume of shoddy that can be generated.
Preferably, the specification provided to the rag mill for poly
shoddy in accord with present invention should include a
requirement to remove the flags and bits from the shredded fiber,
to ensure that a highly sorbent product that is primarily fibers is
produced.
[0061] An additional preferred specification will require the rag
mill to presort the textile/fabric waste that enters the processing
line, to ensure that a desired mixture of fiber types is achieved.
As noted above, a mixture of about 90% synthetic to about 10%
natural fibers is preferred.
[0062] It is likely that the specifications referred to above will
generally increase the processing cost of a delustered synthetic
fiber based sorbent in accord with the present invention, as
compared with traditionally produced poly shoddy. However, the
economics of the rag mill industry are such that poly shoddy is a
relatively low value commodity. At times, the supply of poly shoddy
far exceeds the demand. Under such circumstances, a rag mill may
need to pay to dispose of scrap fabric on hand, rather than shred
the material and hope for a buyer in the future. Providing a
sorbent market for poly shoddy would benefit the rag mill industry
and far outweigh any additional production costs. Finally, because
the value of the raw material is so low, even additional processing
costs will not increase the cost of a poly shoddy based sorbent so
much that it is not competitive with traditional sorbent products.
Indeed, current economic conditions appear to strongly favor a poly
shoddy based sorbent. Those economic conditions, coupled with the
excellent sorbency of such a delustered poly shoddy based sorbent,
and the environmental advantages of using a recycled sorbent, are
anticipated to make such a sorbent product very popular.
[0063] While the sorbent wadded mass of the present invention is
particularly well adapted to be used to remove oil from bodies of
water, due to its rapid sorbency, its high sorbent capacity, its
cohesiveness, its low cost, its ability to be pressed to recover
spilled product, and the fact that its density enables it to float
on the surface of the water, the sorbent wadded mass of the present
invention can also be used in filtering applications. As discussed
in more detail below, a sorbent wadded mass in accord with the
present invention is useable in a filter frame, in which the
sorbent retains its wadded mass configuration. As the following
example documents, the delustered hydrophobic and lipophilic fibers
of the present invention produce a filter media effective in
removing oils, greases, suspended particulates, vegetable oils, and
animal oils. When employed as a filter media, the delustered
hydrophobic and lipophilic fibers do not significantly impede water
flow. Various different filter configurations are possible. While
it is anticipated that a wadded mass will provide superior
filtering abilities, due to the significant interstitial volume in
a wadded mass, it should be noted that some filter applications may
preferably employ a mat or pad configuration, as opposed to a
wadded mass configuration. Even when the delustered hydrophobic and
lipophilic fibers of the present invention are configured in a mat
or pad, such that the additional sorbency of the wadded mass
configuration is not achieved, such delustered hydrophobic and
lipophilic fibers are very useful in removing oils and other
hydrocarbons from a mass of water flowing through the fibers.
Filter units using such delustered hydrophobic and lipophilic
fibers can be designed to have a size and shape compatible with
most filtering applications. Furthermore, while a primary use of
the present invention as a sorbent product is expected to be its
use to remove and recover petroleum products from a water surface,
it should be noted that the present invention is also an excellent
sorbent material for sorbing animal and vegetable oils.
[0064] It has been noted that the wadded mass of the present
invention can be beneficially encapsulated in a porous envelope,
such as a boom. Booms (generally long cylindrical shaped structures
of varying length) are often used to encircle a hydrocarbon spill
to prevent it from spreading over a larger area. Alternatively,
pillows or socks (small booms) are sometimes used for smaller
spills.
[0065] It has been anticipated that booms filled with the
delustered hydrophobic and lipophilic fibers of the present
invention could be employed to completely encircle an oil (or other
hydrocarbon) spill. A ship or barge deploying the booms would
preferably be positioned immediately adjacent to, or even to serve
as part of the booms encircling the spill; and preferably the booms
will be connected end-to-end, to form a continuous boom. The
encircled spill can then be gradually reduced in size, by having
the barge or ship draw some of the booms from the surface, causing
the encircled area to become smaller. During this process, the
withdrawn booms can be pressed to remove any sorbed oil, and the
regenerated booms, from which the oil has been removed, can be
re-deployed along the perimeter of the encircled spill, sorbing
more oil. The process of removing a portion of the booms, reducing
the size of the encircled spill, and replacing spent booms with
freshly regenerated booms would be repeated until the spill is
substantially removed from the surface.
[0066] The delustered shoddy of the present invention can also be
used to produce sorbent blankets and pads. Non-woven sorbent pads
are available in varying sizes, but generally, they are one square
foot in area or less, while sorbent blankets are considerably
larger in area. As will be discussed below, the delustered
hydrophobic and lipophilic fibers of the present invention can be
beneficially employed in a compressed state as a useful sorbent,
although the absorbency provided by the interstitial volumes of the
wadded mat is significantly reduced. One way of producing a sorbent
blanket that retains much of the absorbency of the wadded mass
described above is to provide a "quilted" blanket of the material.
A quilted sorbent blanket, as described herein and the claims that
follow, is an encapsulating envelope produced in sizes and shapes
of conventional sorbent blankets that includes a plurality of
individual chambers, each filled with a wadded mass of delustered
hydrophobic and lipophilic fibers. These individual chambers are
defined by a plurality of baffles, or by a plurality of parallel
channels. A baffle arrangement segments a quilted sorbent blanket
into a plurality of quadrilateral segments joined (or quilted)
together to form the blanket. Each baffle is separate from the
other baffles, and contains a quantity of delustered hydrophobic
and lipophilic fibers in a wadded mass configuration. The
encapsulating baffle is porous, so hydrocarbon can pass through the
baffle and be sorbed by the encapsulated wadded mass. The purpose
of the plurality of baffles is to ensure that the wadded mass
remains evenly distributed throughout the quilted blanket, rather
than clumping together at an end of the blanket. A channel
configuration works the same way, except the channels are generally
elongate in shape, significantly narrower than baffles, and a
single channel generally runs the length of the quilted sorbent
blanket. In a baffle configuration, a plurality of baffles are
required to span the length of the blanket. Such baffles and
channels are commonly used in producing down comforters, to ensure
that the down in such a comforter remains evenly distributed, and
retains a desired loft. The baffles and channels in a quilted
sorbent blanket similarly ensure that the desired wadded mass
configuration of the delustered hydrophobic and lipophilic fibers
is maintained.
[0067] In yet another embodiment of the present invention, a wadded
mass of the delustered hydrophobic and lipophilic fibers is
compressed into a mat or pad. While such a compressed mass of
delustered hydrophobic and lipophilic fibers does not yield results
equivalent to the same fibers in a loose wadded mass (as
compressing the wad into a pad eliminates much of the interstitial
volume in the wadded mass in which absorbency occurs), the
delustered fibers still exhibit very useful adsorbent properties.
Particularly when the fibers have been delustered with titanium
dioxide, each individual fiber exhibits a substantial surface area
(see FIG. 3), enabling each fiber to adsorb much more hydrocarbon
product than can be adsorbed by a non-delustered fiber. Even in a
compacted wadded mass state, delustered hydrophobic and lipophilic
fibers can be beneficially employed in a variety of filter and
sorbent products.
[0068] It is anticipated that delustered hydrophobic and lipophilic
fibers can be used to form non-woven pads, filters, mats and
blankets in a variety of thicknesses, sizes, and shapes. One
technique that is expected to be useful in fabricating such
non-woven sorbent and filter products is needle punching, or needle
weaving. The sorbent fibers are placed on a fine mesh screen of
metal, fiber or plastic. A plurality of hooked needles are
"punched" into the mass, so that the needles penetrate the fine
mesh screen. As the needles are punched into the mass, and then
withdrawn, some of the fibers are caught by the needles, and drawn
through the mesh screen, binding the mass of fibers to the screen
at a plurality of locations, both compressing the mass of fibers
and securely affixing the mass of fibers to the mesh screen. The
resulting needle punched mat can be cut to a desired size or shape,
and employed as a filter, a sorbent pad, a sorbent mat, or a
sorbent blanket (depending on the size of the screen).
Experimental Results
[0069] A plurality of different studies were performed on the
sorbent wadded mass of the present invention. The following section
includes physical characteristics of a preferred embodiment of the
present invention produced from poly shoddy, as well as results and
summaries of different sorption tests performed on the preferred
embodiment.
[0070] Physical Analysis of One Preferred Embodiment
[0071] An independent laboratory analyzed a sample of a preferred
embodiment produced from poly shoddy, using a variety of
micro-analytical techniques, including polarized light and phase
contrast microscopy, dispersion staining, gravimetric, and
flame/hot plate studies. The sample consisted of short (10 mm-15
mm) plugs of fiber, of various types, bound into coherent wads by
much longer (.about.90 mm) mono filament fibers. The fibers were
predominantly stiff, heavily delustered synthetic fibers
(.about.94%), the balance being plant and animal fibers.
Fiber-to-fiber traction was facilitated by fiber lengths as well as
delustering agents, specifically titanium dioxide particles that
had been used to roughen the outer surfaces of the fibers.
[0072] A 90 cubic inch (6 inch.times.5 inch.times.3 inch) sample
was dissected under a stereo dissection microscope, and distinct
fiber types were mounted in a variety of refractive index oils.
Randomized mounts were also selected. The mounts were analyzed with
respect to structure, birefringence, sign of elongation, and
refractive indices, using polarized light and phase contrast. The
results were keyed using the McCrone Research Institute's Particle
Atlas and a dispersion staining guide from the same source. In
addition to the fibers noted below, trace amounts (<1%) of rayon
were noted.
1 Polyester .about.70% .about.45 .mu.m diameter 15-50 mm lengths
(50% delustered) Nylon .about.20% .about.15 .mu.m diameter 15-90 mm
lengths (delustered) Cotton (colored) .about.6% .about.10-30 .mu.m
diameter .about.10 mm lengths Acrylic (Orlon) .about.2%
.about.10-30 .mu.m diameter .about.10 mm lengths Wool .about.1%
.about.10-15 .mu.m diameter .about.7 mm lengths Triacetate <1%
.about.20 .mu.m diameter .about.10 mm lengths Modacrylic <1%
.about.50 .mu.m diameter .about.10 mm lengths
[0073] Absorbent properties are due to large interstitial spaces
and fluid traction on the fiber surfaces. Simple surface area
profiles are enhanced due to the convoluted cross sections of some
fibers, delustering, and penetration of the material being sorbed
into the fiber interior. The following sorption tests were
performed using the sorbent wadded mass analyzed above.
[0074] Recovery of Motor Oil from a Wadded Mass
[0075] The sorbency of the embodiment analyzed above was tested
using motor oil. Less than 0.5 grams (0.4775 grams) of the sorbent
wadded mass were placed in a sample container and 12.5 grams of
motor oil were added. The sorbent wadded mass was allowed 30
minutes to sorb the oil to saturation. The saturated sorbent was
removed, and "allowed" to drip excess oil back into the sample
container for 18 hours. It should be noted that no oil was observed
"dripping" back into the sample container, but for a large portion
of the 18 hours the sorbent was not being continually monitored, so
that it is possible that some unobserved dripping could have
occurred. The oil saturated wadded mass was then weighed, and found
to have sorbed 7.1 grams of oil (15 times its own weight). The oil
saturated wadded mass was then squeezed in a press to recover the
sorbed oil. The recovered oil was weighed, and it was determined
that 87.8% of the 7.1 grams of sorbed oil was recovered simply by
squeezing the sorbent.
[0076] Motor Oil Sorbency Comparison of Wadded Mass with Sorbent
Pad
[0077] The sorbency of the embodiment analyzed described above was
compared to an ASTM Type 1 pad standard using ASTM method F726-81,
"Sorbent Performance of Adsorbents." This test measures the maximum
adsorption of oils and floating immiscible liquids. Three
replicates of the test were performed for each material, using both
motor oil and vegetable oil. On average, the ASTM pad sorbed 7
times of its own weight of vegetable oil, and 8 times of its own
weight of motor oil. In comparison, the wadded mass of present
invention sorbed 17 times of its own weight of vegetable oil, and
21 times of its own weight of motor oil.
[0078] Truck Wash Runoff Samples
[0079] Actual samples from a truck wash runoff were analyzed, both
before and after filtering using the sorbent wadded mass of the
present invention. The test measured the wadded mass' ability to
remove organic pollutants from a water stream. The use of real
world samples ensured that the wadded mass' ability to handle
dissolved hydrocarbons, emulsifiers, detergents, and miscellaneous
debris (dirt, rocks, etc.) was adequately tested. The truck wash
runoff sample was homogenized, and a control sample was analyzed to
determine the baseline levels of various pollutants. Next, the
balance of the sample was passed through a three step filter
process, wherein each step involved passing the sample through a
wadded mass filter. At each step, a noticeable improvement in
clarity, color and odor was observed.
[0080] Particularly notable results involved the reduction is oil
and grease, diesel, and motor oil.
2 Pollutant Unfiltered Filtered Oil & Grease >1000 PPM 6 PPM
Suspended Solids 230 PPM 10 PPM Diesel Oil 910 PPM 3.4 PPM Motor
Oil 15,000 PPM 3 PPM
[0081] Comparison of Wadded Mass and a Prior Art Granular
Sorbent
[0082] The next test compared the sorbency of the wadded mass
(whose physical characteristics are described above), and a
granular polymer based sorbent that is intended to be dispersed on
a spill in a granular form and then reacts to form a jelly-like
mass (see U.S. Pat. No. 5,304,311). The test involved placing
identical amounts of each sorbent in a pre-cleaned sample container
filled with 200 ml of water and 10 g of a motor oil/diesel fuel
mixture. Each sorbent was allowed to sit in the sample mixture for
an identical period of time and then removed. The sample was then
analyzed to determine how much of the motor oil/diesel fuel mixture
was sorbed.
[0083] When a sufficient amount of sorbent was employed, the wadded
mass and granular sorbent each removed over 96% of the motor
oil/diesel fuel mixture from the water. However, several noticeable
differences were observed when smaller amounts of sorbents were
employed. For example, the sorbent wadded mass of the present
invention required only 0.5 grams to sorb 96% of the motor
oil/diesel fuel mixture. In contrast, the granular sorbent required
almost 8 grams to sorb the same 96%. At the point of saturation,
the wadded mass sorbs more than 32 times its own weight, while the
granular sorbent reaches saturation at less than 3.6 times its own
weight. Thus, the wadded mass of the present invention can be
employed in much smaller quantities than the prior art granular
sorbent, and yet will achieve the same result. FIG. 9 graphically
illustrates these findings.
[0084] Additional differences relating to the time required for
sorption were also noted. The wadded mass began visibly sorbing the
motor oil/diesel fuel mixture immediately upon contact, while the
granular sorbent required several minutes to equilibrate and begin
the sorption process.
[0085] Time Required for Wadded Mass to Achieve Peak Sorbency
[0086] A test to determine the oil sorption of a wadded mass (whose
physical characteristics are described above) over time was
performed with used motor oil. Five glass sample jars were used,
each partially filled with water, and each jar also contained 10
grams of oil. The sample glass jars were marked 10, 20, 40, 60, and
120 for the time (in seconds) that the sorbent material would be
allowed to remain in each jar.
[0087] A 1 gram sample of the delustered synthetic fiber wadded
mass was then added to each sample jar. The wadded mass was mixed
continuously after introduction for the specified time period
corresponding to each jar. A stop watch was employed to measure
elapsed time. At the end of the required time period, the wadded
mass was removed from each jar.
[0088] For each jar, it was observed that the sorbent immediately
began removing oil from the water. Also in each jar, residual oil
was observed adhering to the sides of the glass jar, and residual
oil remained there after the wadded mass was removed. After the oil
sorbed wadded mass was removed from each jar, 50 ml of
trichlorotrifluoroethane were added to extract the residual oil
from each jar. The resulting extraction solvent was then
evaporated, and the residual oil was weighed to calculate the
percentage of oil that was sorbed by the wadded mass in each
jar.
[0089] After only 10 seconds of exposure to the wadded mass, over
95% of the oil was removed (9.57 grams of oil). The percentage of
oil removed with further exposure to the wadded mass continued
increase with time, to about 98%, which was achieved after 40
seconds. Because oil was visibly adhering to the sides of the glass
jars, it is believed that after just 40 seconds, substantially all
of the free oil (the oil floating on the water) was removed by the
wadded mass.
[0090] While the present invention has been described in connection
with preferred forms for practicing it and modifications thereto,
those of ordinary skill in the art will understand that many other
modifications can be made to the invention within the scope of the
claims that follow. Accordingly, it is not intended that the scope
of the invention in any way be limited by the above description,
but instead be determined entirely by reference to the claims that
follow.
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