U.S. patent application number 11/074595 was filed with the patent office on 2006-02-02 for diesel emissions filtering system and method.
Invention is credited to William J. Brady.
Application Number | 20060021337 11/074595 |
Document ID | / |
Family ID | 35730597 |
Filed Date | 2006-02-02 |
United States Patent
Application |
20060021337 |
Kind Code |
A1 |
Brady; William J. |
February 2, 2006 |
Diesel emissions filtering system and method
Abstract
The invention is embodied in an emission control system for
reducing diesel particulate matter (DPM) from diesel engine exhaust
gases comprising an aqueous filter apparatus constructed and
arranged to form a water bath for all exhaust gas output from the
engine and including in the water bath a preselected significant
quantity of a low foaming wetting composition having a high
affinity for hydrocarbons. The invention is further embodied in a
diesel emissions filtering method including pre-filtering diesel
fuel and removing DPM from exhaust gases by filtration through an
aqueous solution having a low foaming wetting composition.
Inventors: |
Brady; William J.; (Creve
Coeur, MO) |
Correspondence
Address: |
SENNIGER POWERS
ONE METROPOLITAN SQUARE
16TH FLOOR
ST LOUIS
MO
63102
US
|
Family ID: |
35730597 |
Appl. No.: |
11/074595 |
Filed: |
March 8, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60551086 |
Mar 8, 2004 |
|
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Current U.S.
Class: |
60/310 ; 60/297;
60/311 |
Current CPC
Class: |
F01N 3/04 20130101; Y02T
10/20 20130101; B01D 47/022 20130101; F02B 3/06 20130101; F02M
37/24 20190101; B01D 47/021 20130101; Y02T 10/12 20130101 |
Class at
Publication: |
060/310 ;
060/297; 060/311 |
International
Class: |
F01N 3/00 20060101
F01N003/00; F01N 3/04 20060101 F01N003/04; F01N 3/02 20060101
F01N003/02; F01N 7/12 20060101 F01N007/12 |
Claims
1. An emission control system for reducing diesel particulate
matter (DPM) from the exhaust gas output from a diesel engine,
comprising an aqueous filter apparatus positioned in the exhaust
output passageway from the diesel engine and being constructed and
arranged to form a water bath in said passageway through which all
DPM laden exhaust gases from said engine must pass before being
discharged to ambient, the water bath of said aqueous filter
apparatus comprising water as a major constituent and a wetting
composition as a minor constituent, said wetting composition
comprising a chemical hydrocarbon cleaner including at least one
component selected from the group consisting of detergents, soaps,
surfactants and mixtures thereof, and a defoaming agent.
2. The emission control system of claim 1, in which said aqueous
filter apparatus comprises a gas scrubber tank filled to a
predetermined level with said water bath, said exhaust output
passageway having a discharge end positioned below the level of
said water bath, and gas diffusing means in said tank for
dispersing exhaust outflow gases throughout the water bath.
3. The emission control system of claim 2, wherein said gas
diffusing means comprises a perforated gas discharge pipe at the
discharge end of said passageway whereby to effect percolation of
exhaust gases through the water bath.
4. The emission control system of claim 2, in which said gas
scrubber tank has an exhaust discharge outlet to ambient, and
wherein said gas diffusing means comprises vertical baffle means
disposed in said gas scrubber tank between the discharge end of
said exhaust output passageway into the water bath and said exhaust
discharge outlet to thereby produce circuitous flow paths of
exhaust gases through the water bath in said tank.
5. The emission control system of claim 4, wherein said vertical
baffle means includes plural horizontal ports extending
therethrough to provide limited by-pass flow of exhaust gases
across said circuitous gases flow paths.
6. The emission control system of claim 2, in which said gas
scrubber tank has an exhaust gas inlet end receiving the exhaust
output passageway from the engine, and having an exhaust gas outlet
end above the level of the water bath and forming a gas discharge
outlet to ambient, said gas diffusing means for dispersing
including at least two mixing means for creating circuitous and
turbulent flow of exhaust gases through said water bath.
7. The emission control system of claim 6, wherein one of said
mixing means comprises a perforated gas discharge pipe on the inlet
side of said scrubber tank for discharging of exhaust gases from
said exhaust output passageway through the water bath.
8. The emission control system of claim 6, wherein one of said
mixing means comprises a plurality of baffles between the inlet and
outlet ends of said scrubber tank to circulate exhaust gases
intimately throughout the water in serpentine flow paths around and
between the baffles.
9. The emission control system of claim 8, including another mixing
means in the form of ports through the baffles to accommodate minor
limited direct flow of a portion of exhaust gases through the
baffles in a direction substantially perpendicular to the
serpentine flow direction of exhaust gases around and between the
baffles.
10. The emission control system of claim 1, including water level
sensing means for assuring safe operating water levels of said
water bath.
11. The emission control system of claim 1, in which said aqueous
filter apparatus comprises water curtain means for discharging an
aqueous water wall formed of a solution of said major body of water
and minor amount of super-wetting agent.
12. The emission control system of claim 11, in which said water
curtain means comprises closed scrubber tank means having a gas
inlet side connecting to the engine and a gas discharge side
connecting to ambient, a supply source of blended water and wetting
composition, and water spray means for discharging a continuously
flowing curtain wall of such solution across the tank means, and
said gas inlet side having gas dispersing means for discharging
exhaust gases from the engine throughout the upstream inlet side
for passage therefrom through the curtain wall to the downstream
outlet side.
13. The emission control system of claim 12, in which said supply
source hold a relatively large amount of blended water and wetting
composition and said scrubber tank means is relatively small, and
said scrubber tank means including discharge means for outflowing
used solution from the bottom thereof.
14. The emission control system of claim 13, in which said scrubber
tank means has a volumetric capacity in the range of 4 to 10 gal.
and said supply source of solution comprises a solution blending
tank having a volumetric capacity in the range of 25 to 60 gal.
15. The emission control system of claim 12, including means for
regulating the flow of solution to said water spray means.
16. The emission control system of claim 2, in which said aqueous
filter apparatus comprises a gas scrubber tank of relatively large
size holding a water bath in the volumetric range of 25 to 55
gal.
17. The emission control system of claim 2, in which said gas
scrubber tank has a relatively small size holding a water bath in
the volumetric range of 3 to 10 gal., and a supply source of
blended water and wetting composition solution constructed and
arranged for maintaining the water bath level in said scrubber
tank.
18. The emission control system of claim 1, in combination with a
diesel fuel pre-filter constructed and arranged upstream of the
diesel engine for removing non-fuel contaminates from the diesel
fuel to thereby improve engine performance.
19. The emission control system of claim 18, in which said fuel
pre-filter is interposed in the fuel supply line to the diesel
engine, and is constructed for filtering non-combustible
contaminates of the diesel fuel whereby to provide a substantially
totally-combustible diesel fuel supply to the engine.
20. The emission control system of claim 19, in which said fuel
pre-filter includes a first filter for filtering water out of the
diesel fuel, and a second filter for filtering air out of the
diesel fuel.
21. The emission control system of claim 1, in which the wetting
composition is phosphate-free.
22. The emission control system of claim 21, in which the wetting
composition is nitrate-free.
23. The emission control system of claim 1, in which the chemical
hydrocarbon cleaner is low-foaming.
24. The emission control system of claim 23, wherein the chemical
hydrocarbon cleaner comprises at least one surfactant selected from
the group consisting of anionic surfactants, cationic surfactants,
nonionic surfactants, amphoteric surfactants and mixtures
thereof.
25. The emission control system of claim 23, wherein the wetting
composition further comprises an organic solvent.
26. The emission control system of claim 25 wherein the chemical
hydrocarbon cleaner comprises an anionic surfactant.
27. The emission control system of claim 26 wherein the anionic
surfactant is selected from alkylether sulfates, alkyl sulfates and
mixtures thereof.
28. The emission control system of claim 25 wherein the chemical
hydrocarbon cleaner comprises an amphoteric surfactant.
29. The emission control system of claim 25 wherein the chemical
hydrocarbon cleaner comprises a nonionic surfactant.
30. The emission control system of claim 29 wherein the nonionic
surfactant is selected from the group consisting of ethoxylated
alcohol, alkanolamines and mixtures thereof.
31. The emission control system of claim 30 wherein the nonionic
surfactant comprises an ethoxylated nonylphenol.
32. The emission control system of claim 31 wherein the nonionic
surfactant comprises a mixture of an ethoxylated nonylphenol and an
alkanolamine.
33. The emission control system of claim 32 wherein the nonionic
surfactant comprises a mixture of an nonoxynol 10 and
monoethanolamine.
34. The emission control system of claim 31 wherein the organic
solvent comprises an alkylene glycol ether.
35. The emission control system of claim 34 wherein the organic
solvent comprises dipropylene glycol methyl ether.
36. The emission control system of claim 31 wherein the defoaming
agent is selected from petroleum-based antifoams, silicone-based
antifoams and mixtures thereof.
37. The emission control system of claim 36 wherein the defoaming
agent comprises a silicon-based antifoam.
38. The emission control system of claim 37 wherein the
silicon-based anti-foam comprises an organosiloxane.
39. The emission control system of claim 38 wherein the
silicon-based anti-foam comprises polydimethylsiloxane.
40. The emission control system of claim 31 wherein the wetting
composition further comprises a coupling agent.
41. The emission control system of claim 40 wherein the coupling
agent comprises tetrasodium EDTA.
42. The emission control system as set forth 41 wherein the
chemical hydrocarbon cleaner comprises a soap formed by saponifying
a tall oil fatty acid with a caustic comprising an
alkanolamine.
43. The emission control system as set forth in claim 1 wherein the
wetting composition comprises: water; a chemical hydrocarbon
cleaner comprising ethoxylated nonylphenol nonionic surfactant and
a soap formed by saponifying a tall oil fatty acid with
monoethanolamine; an organic solvent comprising dipropylene glycol
methyl ether; a coupling agent comprising tetrasodium EDTA; and a
defoaming agent comprising a silicone-based antifoam.
44. The emission control system of claim 43 wherein the ethoxylated
nonylphenol nonionic surfactant comprises nonoxynol 10.
45. The emission control system of claim 44 wherein the
silicone-based antifoam comprises a polydimethylsiloxane.
46. The emission control system of claim 1 wherein the wetting
composition comprises: at least about 35% by weight water; a
chemical hydrocarbon cleaner comprising an ethoxylated nonylphenol
nonionic surfactant and a soap formed by saponifying a tall oil
fatty acid with monoethanolamine, wherein the composition comprises
from about 10% to about 30% by weight ethoxylated nonylphenol
nonionic surfactant, from about 2% to about 8% by weight tall oil
fatty acid and from about 1% to about 5% by weight
monoethanolamine; an organic solvent comprising dipropylene glycol
methyl ether, wherein the composition comprises from about 5% to
about 15% by weight dipropylene glycol methyl ether; a coupling
agent comprising tetrasodium EDTA, wherein the composition
comprises at least about 0.5% by weight tetrasodium EDTA; and a
defoaming agent comprising a silicon-based antifoam, wherein the
composition comprises at least about 1% by weight silicon-based
antifoam.
47. The emission control system of claim 46 wherein the ethoxylated
nonylphenol nonionic surfactant comprises nonoxynol 10.
48. The emission control system of claim 46 wherein the
silicone-based antifoam comprises a polydimethylsiloxane.
49. The emission control system of claim 2, in which said gas
scrubber tank has an exhaust discharge outlet leading to ambient
and, in combination therewith, a final gas filter constructed and
arranged to filter substantially all residual DPM material from the
cooled and cleaned exhaust gases passing from the gas scrubber
tank.
50. A diesel cleaning system for achieving optimum diesel engine
performance and maximum removal of DPM and CO from diesel exhaust
emission gases, comprising the steps of: pre-filtering diesel fuel
upstream of a diesel engine to remove non-combustibles and enhance
more complete fuel burning to minimize residual hydrocarbon content
in exhaust gases; dispersing diesel exhaust emission gases through
a water bath having water as a major constituent and as a minor
constituent a wetting composition comprising a chemical hydrocarbon
cleaner comprising at least one component selected from the group
consisting of detergents, soaps, surfactants and mixtures thereof,
and a defoaming agent, to thereby remove the majority of DPM matter
from such gases.
51. A method of improving diesel engine performance and removing
deleterious materials from diesel fuel and diesel exhaust gases,
comprising the steps of: pre-filtering diesel fuel upstream of the
engine to remove non-combustible contaminates therefrom; filtering
diesel exhaust gases downstream of the engine to remove DPM and
carbon monoxide therefrom including the step of passing such
exhaust gases through an aqueous water bath having water as a major
constituent and as a minor constituent a wetting composition
comprising a chemical hydrocarbon cleaner comprising at least one
component selected from the group consisting of detergents, soaps,
surfactants and mixtures thereof, and a defoaming agent.
52. A DPM removal method for removing diesel particulate matter
(DPM) from the exhaust gas emission of diesel engines used in class
32 gaseous environment applications, including the steps of:
providing water scrubber means downstream of the diesel engine to
receive exhaust gas outflow therefrom, providing an aqueous
solution for the water scrubber means comprising a water bath
having water as a major constituent and as a minor constituent a
wetting composition comprising a chemical hydrocarbon cleaner
comprising at least one component selected from the group
consisting of detergents, soaps, surfactants and mixtures thereof,
and a defoaming agent, and creating an intimate dispersion of the
exhaust gas emission through the aqueous solution of the water
scrubber means.
53. The method of cleaning carbonaceous matter from a first medium,
comprising the steps of: selecting a chemical hydrocarbon cleaner
including at least one component selected from the group consisting
of detergents, soaps, surfactants and mixtures thereof; selecting a
defoaming agent as a secondary constituent; formulating a wetting
composition by combining the primary and secondary constituents in
pre-determined proportion; admixing a major portion of water with a
minor portion of the wetting composition to constitute an aqueous
solution as a second medium; and dispersing one of said first and
second mediums intimately with the other of said mediums to
effectively remove carbonaceous matter from the first medium to the
second medium.
54. A wetting composition useful in treating diesel exhaust
emission gases to reduce the concentration of particulate matter
and/or carbon monoxide, the composition comprising: water; a
chemical hydrocarbon cleaner comprising at least one component
selected from the group consisting of detergents, soaps,
surfactants and mixtures thereof; and a defoaming agent.
55. The wetting composition of claim 54 wherein the composition is
phosphate-free.
56. The wetting composition of claim 54 wherein the composition is
nitrate-free.
57. The wetting composition of claim 54 wherein the chemical
hydrocarbon cleaner is low-foaming.
58. The wetting composition of claim 54 wherein the chemical
hydrocarbon cleaner comprises at least one surfactant selected from
the group consisting of anionic surfactants, cationic surfactants,
nonionic surfactants, amphoteric surfactants and mixtures
thereof.
59. The wetting composition of claim 58 further comprising an
organic solvent.
60. The wetting composition of claim 59 wherein the chemical
hydrocarbon cleaner comprises an anionic surfactant.
61. The wetting composition of claim 60 wherein the anionic
surfactant is selected from alkylether sulfates, alkyl sulfates and
mixtures thereof.
62. The wetting composition of claim 59 wherein the chemical
hydrocarbon cleaner comprises an amphoteric surfactant.
63. The wetting composition of claim 59 wherein the chemical
hydrocarbon cleaner comprises a nonionic surfactant.
64. The wetting composition of claim 63 wherein the nonionic
surfactant is selected from the group consisting of ethoxylated
alcohol, alkanolamines and mixtures thereof.
65. The wetting composition of claim 64 wherein the nonionic
surfactant comprises an ethoxylated nonylphenol.
66. The wetting composition of claim 65 wherein the nonionic
surfactant comprises a mixture of an ethoxylated nonylphenol and an
alkanolamine.
67. The wetting composition of claim 66 wherein the nonionic
surfactant comprises a mixture of an nonoxynol 10 and
monoethanolamine.
68. The wetting composition of claim 65 wherein the organic solvent
comprises an alkylene glycol ether.
69. The wetting composition of claim 68 wherein the organic solvent
comprises dipropylene glycol methyl ether.
70. The wetting composition of claim 65 wherein the defoaming agent
is selected from petroleum-based antifoams, silicone-based
antifoams and mixtures thereof.
71. The wetting composition of claim 70 wherein the defoaming agent
comprises a silicon-based antifoam.
72. The wetting composition of claim 71 wherein the silicon-based
anti-foam comprises an organosiloxane.
73. The wetting composition of claim 72 wherein the silicon-based
anti-foam comprises polydimethylsiloxane.
74. The wetting composition of claim 65 further comprises a
coupling agent.
75. The wetting composition of claim 74 wherein the coupling agent
comprises tetrasodium EDTA.
76. The wetting composition of 65 wherein the chemical hydrocarbon
cleaner comprises a soap formed by saponifying a tall oil fatty
acid with a caustic comprising an alkanolamine.
77. A wetting composition useful in treating diesel exhaust
emission gases to reduce the concentration of particulate matter
and/or carbon monoxide, the composition comprising: water; a
chemical hydrocarbon cleaner comprising ethoxylated nonylphenol
nonionic surfactant and a soap formed by saponifying a tall oil
fatty acid with monoethanolamine; an organic solvent comprising
dipropylene glycol methyl ether; a coupling agent comprising
tetrasodium EDTA; and a defoaming agent comprising a silicone-based
antifoam.
78. The wetting composition of claim 77 wherein the ethoxylated
nonylphenol nonionic surfactant comprises nonoxynol 10.
79. The wetting composition of claim 78 wherein the silicone-based
antifoam comprises a polydimethylsiloxane.
80. A wetting composition useful in treating diesel exhaust
emission gases to reduce the concentration of particulate matter
and/or carbon monoxide, the composition comprising: at least about
35% by weight water; a chemical hydrocarbon cleaner comprising an
ethoxylated nonylphenol nonionic surfactant and a soap formed by
saponifying a tall oil fatty acid with monoethanolamine, wherein
the composition comprises from about 10% to about 30% by weight
ethoxylated nonylphenol nonionic surfactant, from about 2% to about
8% by weight tall oil fatty acid and from about 1% to about 5% by
weight monoethanolamine; an organic solvent comprising dipropylene
glycol methyl ether, wherein the composition comprises from about
5% to about 15% by weight dipropylene glycol methyl ether; a
coupling agent comprising tetrasodium EDTA, wherein the composition
comprises at least about 0.5% by weight tetrasodium EDTA; and a
defoaming agent comprising a silicon-based antifoam, wherein the
composition comprises at least about 1% by weight silicon-based
antifoam.
81. The wetting composition of claim 80 wherein the ethoxylated
nonylphenol nonionic surfactant comprises nonoxynol 10.
82. The wetting composition of claim 80 wherein the silicone-based
antifoam comprises a polydimethylsiloxane.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a non-provisional of U.S. application Ser. No.
60/551,086, filed Mar. 8, 2004, the entire disclosure of which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to diesel fuel control
systems, and more particularly to diesel systems and methods for
reducing hydrocarbon and diesel particulate matter levels in diesel
exhaust emissions to assure safe environmental operation of diesel
engines.
[0004] 2. Description of the Prior Art
[0005] Internal combustion engines are designed to operate most
efficiently on standard quality fuels, and the presence of
impurities or non-combustible contaminates may result in poor
engine performance or impairment as well as produce higher levels
of exhaust impurities. Even small quantities of water in diesel
fuel may prevent satisfactory operation of a diesel engine, and
most diesel engines now have some type of water-separator in
addition to filters for removing sediment or other solids that may
have been introduced into the fuel tank. It is also now known that
the presence of air entrained in diesel fuel delivered to a fuel
injection system results in poorer engine performance since the
amount of air required for optimum combustion is already precisely
controlled by the fuel injection system itself. It is thus clear
that the presence of these non-fuel contaminates in a diesel fuel
delivery system result in poor engine performance with the extended
result of less complete fuel burning and an increase in deleterious
exhaust pollutants.
[0006] During operation diesel engines produce various exhaust
pollutants including unburned hydrocarbons, carbon and nitrogen
oxides, sulfurous gases and other particulate matter generally
called "diesel particulate matter" (DPM). Aside from the
environmental interests in reducing such air pollution generally,
there is an absolute necessity of doing so in certain diesel
operating environments. There is a prevalent use of diesel engine
powered equipment in fiery gaseous mining applications where
methane gas is present; and the Federal government, through the
Mine Safety Health Administration (MSHA), has set rigid regulations
for the design and operation of such diesel engines (particularly
for class 32 machinery that operates underground in the vicinity of
the mining cut--as opposed to class 24 equipment which operates
outby or outdoors in fresh air). Thus the preparation or
modification of diesel engines for use in class 32 gaseous
applications has reference to flame paths, skin temperatures of
engine and attachments, final exhaust temperatures and final
exhaust gas emission analysis and shut-down systems.
[0007] A primary troublesome area has been the control of exhaust
gas emissions, and the Federal government has heretofore mandated
the use of "soot trap filters" to reduce DPM emissions exhaust
levels by filtering hydrocarbons out of the diesel exhaust gases.
However, the use of dry filter soot traps on the end of a diesel
exhaust has generally posed a fire hazard problem irrespective of
what the filter material (steel, fibreglass, ceramic, etc.) is made
of, since the accumulation of DPM hydrocarbons at normal engine and
exhaust operating temperatures may cause an explosion in a gaseous
coal mine. For instance, diesel engine combustion temperatures may
be 800.degree.-1100.degree. F., so significant engine and exhaust
pipe cooling should be effected to reduce gas emissions
temperatures below the ignition temperature of hydrocarbon
accumulations in the soot trap. High exhaust gas temperatures are
especially hazardous in the operation of class 32 diesel engines in
coal mines or like closed environments where methane gas may be
present since methane has an ignition temperature of 302.degree. F.
In past practice, the exhaust lines from class 32 diesel engines
have been insulated with "Thermogram" or the like so that the high
(800.degree. F.) combustion temperature would be carried by diesel
exhaust gases past the catalytic converter to the soot trap thus
producing the probability of fires and/or explosions therein with
the result that mine operators refuse to use the mandated soot
traps for safety reasons and generally continue to operate under
violation citations from the Mine Safety and Health Administration
(MSHA), which recognizes the danger and reason for the continuing
violation.
[0008] It has been reported that the mandated dry soot traps are
still fire hazards even after the engine is shut off because oxygen
will flow from ambient back into the hot trap and ignite the
carbon/hydrocarbon DPM accumulation therein. In short, any dry soot
trap per se almost always poses a fire hazard and, in addition,
soot traps are labor intensive and expensive.
[0009] In the past the foregoing fire hazard problem has been
approached by attempting to provide exhaust gas cooling means,
generally in the form of a so-called gas scrubber consisting of a
body of water into which the exhaust gases were passed and cooled.
Typical of the prior art directed to such water scrubbers are the
following U.S. Pat. No. 3,957,467 granted May 18, 1976 (Kim); U.S.
Pat. No. 3,976,456 granted Aug. 24, 1976 (Alcock); and U.S. Pat.
No. 4,190,629 granted Feb. 26, 1980 (Strachan). However, the
apparatus of these patents primarily only cools the exhaust gas,
but has no other major effect since only a small portion of DPM
matter will be trapped in plain hard mine water, and also no
significant carbon monoxide will be removed. The Kim U.S. Pat. No.
3,957,467 states that a gas purification liquid may be used and, in
addition to water alone, it is suggested that aqueous solutions may
include other non-specific additives such as detergent, surfactant
or wetting agents, alcohol, glycol or alkalis.
SUMMARY OF THE INVENTION
[0010] The invention is embodied in an emission control system for
cleaning diesel particulate matter (DPM) from diesel engine exhaust
gases and comprising an aqueous filter apparatus forming a water
bath having a major water portion with a minor portion of
super-wetting agent ("wetting composition") having a high affinity
for hydrocarbons. The invention is further embodied in a diesel
emissions filtering method including the features of pre-filtering
diesel fuel, and removing DPM from diesel exhaust gases comprising
filtering such gases through an aqueous solution having a minor
portion of a low foam super-wetting agent, and finally filtering
the exhaust gases.
[0011] A principal object of the invention is to provide systems,
apparatus and methods for removing significant amounts of diesel
particulate matter from diesel exhaust gases prior to final
discharge thereof to ambient.
[0012] Another object is to substantially reduce carbon monoxide
levels in the final emission gases prior to discharge to
ambient.
[0013] An object of the invention is to provide a diesel filtering
method comprising pre-filtering diesel fuel to remove
non-combustible matter upstream of the engine, removing DPM and
carbon monoxide from diesel exhaust gases downstream of the engine,
and final filtering the exhaust gases before discharge to
ambient.
[0014] Another object of the invention is to provide more effective
ways of removing DPM and carbon monoxide matter from diesel exhaust
gases using low cost systems and equipment and labor saving
methods.
[0015] It is another objective to greatly improve the working
environment around diesel powered equipment, particularly in coal
mines and like underground sites with potential methane gas or
other hazardous gas presence.
[0016] Another object is to provide exhaust gas scrubber systems
and methods that are effective in removing DPM matter and carbon
monoxide from diesel exhaust gases prior to passing to a final
filter, as presently mandated by MSHA, and which will thereby
prolong the useable life and reduce the costs of using such final
filters. It is a still further object to provide such systems,
apparatus and methods whereby the present requirements for final
exhaust filters may be changed in recognition that such final
filters are no longer needed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In the accompanying drawings wherein like numerals refer to
like parts wherever they occur:
[0018] FIG. 1 is a diagrammatic view showing a diesel engine fuel
system embodying one aspect of the invention from fuel tank to
emissions exhaust;
[0019] FIG. 2 is an enlarged diagrammatic view of the emissions
exhaust filtering section of the system.
[0020] FIG. 3 is a diagrammatic view illustrating another
embodiment of an emissions exhaust filtering section of the
invention;
[0021] FIG. 4 is another diagrammatic view showing a further
embodiment of the exhaust filtering section; and
[0022] FIG. 5 is a cross-sectional view taken along line 5-5 of
FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0023] Referring to the diagrammatic overview of a diesel fuel
system of the invention as shown in FIG. 1, this system includes a
fuel delivery section FD between the fuel tank 10 and the diesel
engine 12 and an emissions exhaust section EE from the engine 12 to
ambient.
[0024] One feature of the invention is to deliver a substantially
pure diesel fuel to the engine, i.e., fuel that is free from air,
water and other unwanted gases or non-combustible contaminates.
Thus, in the preferred embodiment, the fuel delivery section FD of
the diesel system includes fuel pre-filtration means including a
water filtration or separator unit 14 connected by fuel line 15 to
the fuel tank 10, and a particle filtration unit 18 connected in
line 17 through fuel pump 20 to the water filter 14. In this
preferred embodiment the water filter unit 14 and particle filter
unit 18 form a primary or initial fuel filter means 21, and a
secondary fuel filter means 22 is connected through a flow rate
regulator valve 24 in line 23 to the primary filtration means 14,
18.
[0025] The secondary fuel filter 22 includes a vessel 26 having an
interior separation chamber 27 constructed and arranged to
fluidically connect through delivery line 28 to the fuel injection
system (not shown) for the engine 12, and also has a return line 29
connecting back to the fuel tank 10. An air purge means (not shown)
can be provided at the top of the vessel 26 to bleed air out of the
fuel delivery system. U.S. Pat. Nos. 5,746,184 and 5,355,860 are
incorporated by reference as disclosing features of one suitable
pre-filtration means of the fuel delivery section FD in greater
detail.
[0026] In operation, the fuel delivery section FD provides for the
positive delivery of diesel fuel from the fuel tank 10 to the
injection system (not shown) of diesel engine 12. Pump 20 assures
positive flow through both the primary and secondary fuel filter
means 21, 22 in which air, water and other non-fuel impurities are
removed. Thus, optimum engine performance can be achieved through
pre-filtration of diesel fuels with the result that maximum burning
of diesel fuel will result in lower levels of diesel particulate
matter (DPM) in the emission exhaust gases from the engine 12.
Nonetheless, the unburned hydrocarbon content of engine exhaust
gases has, in the past, continued to be a major safety and health
concern in the operation of diesel engines--particularly in closed,
poorly ventilated areas such as underground mines.
[0027] The major feature of the invention is to deliver diesel
engine discharge gases (with inherent hydrocarbon DPM content)
through the emission exhaust section EE, which includes exhaust gas
scrubber means for safely removing such DPM content, reducing
carbon monoxide levels and discharging cleaned exhaust gases to
ambient. The effectiveness of this feature of the invention is
achieved primarily by providing an aqueous solution in the gas
scrubber section EE that includes a super-wetting agent ("wetting
composition"), and the following definitions will be instructive in
the disclosure and claiming of this feature of the invention:
[0028] DPM (diesel particulate matter) as used herein shall
generally mean all forms of hydrocarbon and other carbonaceous
matter, carbon or nitrogen oxides, sulfurous gases and related
particulate matter. DPM may also be referred to as "particulate
carbonaceous matter".
[0029] Referring now again to FIG. 2 of the drawings, the exhaust
scrubber portion EE of the system includes an aqueous filter
apparatus positioned in the exhaust output passageway from the
diesel engine 12 to ambient. More specifically, the aqueous filter
apparatus forms a water bath WB through which all DPM laden exhaust
gases are passed and cleaned before being discharged to ambient. In
a preferred form of the invention, the water bath WB of filtering
apparatus is contained in a scrubber tank 33 that has an exhaust
intake 34 connected by exhaust pipe 35 to the exhaust manifold (not
shown) of the engine 12. The exhaust pipe 35 is covered by a
suitable insulation covering 36, such as "Thermogram", to shield
the high discharge gas temperatures (i.e., 800.degree. to
1100.degree. F.) from the surrounding ambient. In FIG. 2 it will be
seen that the tank 33 has an internal extension pipe 37 connected
to the exhaust pipe 35 and extending into the tank 33 below the
level 38 of the water bath WB. A gas discharge diffuser 39 is
provided at the exit end of the exhaust extension pipe 37 to break
up and disperse the exhaust gas stream as it is discharged from the
extension 37 into the water bath WB in the tank 33. For
illustration purposes the diffuser 39 is simply shown as an
elongate pipe having a series of discharge openings 40, but it will
be understood that a wide variety of gas diffusing means, such as
in the form of perforations, screens and turbulence producing
means, may be employed. The openings 40 are preferably arrayed
along the length and around the circumference of the diffuser 39.
The diffuser means (39) of the invention should act to disperse or
spread out the gas stream for mixture into or percolation through
the water bath WB and it may act to partially decelerate the
entering gas stream to a lower velocity. However, it is important
that any retardant effect should be controlled to a minimum so as
to not create undue back pressure on the diesel engine 12.
[0030] The scrubber tank 33 may be any suitable shape, such as
cubicle or cylindrical, and holds a pre-determined volume of liquid
in the range of 35 to 50 gallons. The exhaust intake 34 is located
at one end of this tank, and the tank also has a gas discharge or
outlet 42 located at the other tank end and positioned above the
water bath level 38 in such manner that the exhaust gases must
traverse through the water bath the length of the scrubber tank 33
from the diffuser (40) at the intake end to the outlet port 42 at
the exit end. A final filter 43 of ceramic or fiberglass is shown
connected at the gas discharge outlet (as currently mandated by
MSHA for class 32 diesel operations). It is believed that the
present invention will minimize any need for a final filter 43, as
will be shown.
[0031] In addition to the diffusing means (39, 40) for dispersing
or breaking up the exhaust gas stream as it enters the water bath
WB, the tank 34 is provided with baffle means (44, 45) projecting
vertically into the body of water in the tank and extending across
the tank from side to side. The baffle means (44, 45) are
constructed and arranged to create tortuous or circuitous gasflow
pathways to increase the turbulence and mixing contact of DPM laden
gas molecules with the water bath WB. In the form of the invention
shown in FIG. 2, first baffles 44 are arranged to extend upwardly
from the floor 46 of the tank or just above the floor, and have
upper ends 44a below the water level 38. Second baffles 45 are
arranged to extend downwardly from the top 47 of the tank and have
lower end margins 45a within the water bath and spaced above the
floor 46. The first and second baffle means are alternately
arranged to create major tortuous pathways having primary vertical
channels therebetween and being connected around the baffle end
margins (44a, 45a), as shown by the curved arrows. The baffles 44,
45 are also shown with minor secondary through-ports 49 to provide
for small portions of exhaust gases to flow directly through these
baffles and impinge on the major gas portions flowing in a vertical
direction in the primary vertical passageways whereby to cause
further turbulence and scrubbing action between the gases and the
water bath WB. It should be noted that the baffles 45 extend across
the tank from the top (47) downwardly into the water bath thereby
forming a vapor barrier or seal above the waterline so that exhaust
gases must flow through the water bath in the major passageways to
reach the final exit port 42 from the tank 33. The tank 33 also has
a water fill pipe 50 and water level float 51, and the bottom of
the tank may have an outlet 74 or like drain provision for periodic
flushing of the tank as may be required.
[0032] Super-wetting agent or wetting composition as used herein
shall generally mean an aqueous mixture comprising a combination of
a chemical hydrocarbon cleaner and a defoaming agent, the
composition typically in the form of a colloid, suspension,
emulsion or solution.
[0033] A colloid (i.e., colloidal system) as used herein shall
generally mean a dispersion of finely divided particles in a
continuous liquid medium--the particles being in a mid-size range
between a true solution (1 millimicron or nanometer) and a coarse
dispersion or suspension (1 micron or micrometer). Emulsion as used
herein shall generally mean a stable mixture of two or more
immiscible liquids held in suspension by a surface-active
"emulsifier" that is either (1) a protein or carbohydrate polymer
which coats the surfaces of dispersed fat (oil) particles to
prevent coalescing (called a protective colloid) or (2) a
long-chain alcohol and fatty acid which reduces surface tension at
the interface of suspended soluble particles. Emulsions consist of
a continuous phase and a disperse phase in which small globules of
one liquid are suspended in a second liquid by a wetting or
deterging agent.
[0034] An important aspect of the invention resides in the
selection of suitable combination of chemical hydrocarbon cleaner
and defoaming agent to formulate an acceptable wetting composition
for use in the aqueous mixture of the water bath WB. In the past
water scrubbers have been placed in diesel exhaust lines to cool
exhaust gases and, of course, some amount of particulate soot
materials will be removed from these gases. However, it is known
that the carbonaceous matter or DPM is basically immiscible in
water and that only a very small portion of DPM will be suspended
in the water of these prior art traps; and that no carbon monoxide
will be removed therein. Thus, it is presently mandated that all
scrubbers (soot traps) of any kind used on class 32 diesel
equipment in coal mines be equipped with a "stop work float device"
to ensure that hydrocarbon sludge in the tank does not reach
kindling temperature and catch fire. It is also known that various
natural and chemical surfactants, detergents and/or wetting agents
in aqueous solution can attract hydrocarbons from exhaust gases and
hold them in the water of a scrubber, but the resulting foaming
action of such additives often creates unacceptable conditions and
environmental problems.
[0035] It will be understood that the wetting composition of the
invention should preferably be able to function effectively in hot
environments (e.g., about 800.degree. to 1100.degree. F.), which is
the typical temperature range of exhaust gases entering the aqueous
solution of the scrubber (33). Furthermore, the wetting composition
should desirably be able to react very fast and bond with
hydrocarbons and carbon compounds and pull them from the exhaust
gases. It is believed that the high gas temperature may act to
accelerate this bonding reaction of the chemical hydrocarbon
cleaner (e.g., surfactant) with the DPM and also the removal of
carbon monoxide (CO) from the exhaust stream. The turbulence
generated by the rapid flowing exhaust gases entering the scrubber
and being dispersed by the diffuser through the water bath produces
greater surface area contact and more complete removal of DPM and
CO from the exhaust.
[0036] The chemical hydrocarbon cleaner is preferably selected so
as to be able to reduce the amount of DPM and CO present in the
exhaust gas entering the scrubber. In addition, a suitable wetting
composition of the present invention has a fast reaction in
attracting and holding DPM due to the high velocity of the exhaust
gas stream entering the scrubber tank (33), even though the
diffuser means (39) may have a retardant effect on the dispersed
gas. In one embodiment, the present invention attracts and holds
the DPM 3 to 5 times or even faster than previous scrubbing
methods.
[0037] In accordance with one embodiment of the present invention,
various wetting compositions have been devised for use in
conjunction with a diffusing means for dispersing exhaust gases
throughout the water bath of a scrubber, thereby obviating prior
art shortcomings and achieving superior diesel exhaust gas
cleansing of DPM and reduction of carbon monoxide levels.
[0038] The chemical hydrocarbon cleaner may be suitably selected
from various detergents, soaps, surfactants and mixtures thereof.
Detergent as used herein generally means any deterging or cleaning
agent produced from synthetic organic compounds (rather than
natural fats or oils and alkali as in soaps). Detergents are
soluble in water, and highly foamable and act as a wetting agent
and emulsifier.
[0039] In one embodiment, the chemical hydrocarbon cleaner used in
the present invention may include a soap. Soap as used herein shall
generally mean a deterging or cleaning agent made by reacting a
natural fatty acid (e.g., tall oil fatty acid) or oil with an
alkali or caustic (such as sodium or potassium hydroxide or an
alkanolamine such as monoethanolamine) to produce the corresponding
soap with glycerol as a by-product. Soaps, like detergents, exhibit
surface-active properties, such as foaming, detergency and lowering
of surface tension.
[0040] Surfactant as used herein shall mean any of the class of
surface-active agents including (or are included in) detergents,
soaps, colloids and emulsifiers. Surfactants are surface-active
agents that reduce the surface tension of water and cause it (1) to
penetrate more easily into, or spread over the surface of, another
material or (2) be penetrated by or become a dispersion of another
material. Surfactants are wetting agents that orient themselves at
the molecular interface of water with other surfaces and modify the
liquid properties at the interface. A surfactant typically consists
of two parts: a hydrophobic portion (e.g., a long hydrocarbon
chain) and a hydrophilic portion that makes the entire compound
soluble or dispensable or dispersable in water and these
hydrophobic and hydrophilic moieties render the compound
surface-active. Surfactants suitable for use in the practice of the
present invention are generally classified as anionic, cationic,
nonionic, or amphoteric.
[0041] Preferably, in order to alleviate environmental concerns,
the wetting composition is formulated to be phosphate and
nitrate-free. Furthermore, the chemical hydrocarbon cleaner is
preferably low-foaming to mitigate production of foam during use.
Nonionic surfactants generally have lower sudsing or foaming
characteristic than anionic surfactants (cationic surfactants are
primarily used in industrial chemical processing). Accordingly, in
view of these concerns, in a preferred embodiment described in
greater detail below, the chemical hydrocarbon cleaner utilized in
the wetting composition comprises a nonionic surfactant.
[0042] Examples of suitable nonionic surfactants for use in the
chemical hydrocarbon cleaner component of the wetting composition
include ethoxylated alcohols, alkanolamines, and mixtures thereof.
In accordance with a preferred embodiment, the chemical hydrocarbon
cleaner includes an ethoxylated nonylphenol nonionic surfactant,
for example, n-molar ethoxylated nonylphenols or mixtures thereof,
sometimes denoted as nonoxynol-n, where n is a rational number
between about 2.5 and about 15. Such nonionic surfactants are
available from Huntsman Chemical (Salt Lake City, Utah). In an
especially preferred embodiment, the ethoxylated nonylphenol
nonionic surfactant comprises nonoxynol 10 either alone or in
combination with an alkanolamine nonionic surfactant such as
monoethanolamine.
[0043] Even in embodiments where a low-foaming nonionic surfactant
is employed as the hydrocarbon cleaning agent, the wetting
composition of the present invention advantageously further
includes a defoaming agent. Indeed, the use of a defoaming agent is
an important aspect of the invention in that it provides a wetting
composition that does not foam excessively, in short, that it
maintain a substantially liquid state at all times. Known defoaming
agents have a variable range of effectiveness. Accordingly, the
concentration of the defoaming agent in the wetting composition may
vary considerably in order to attain suitable mitigation of foam
production during use, but generally is at least about 1% by
weight, more typically at least about 5% by weight and preferably
from about 5% to about 15% by weight. The concentration of the
defoaming agent in the wetting composition necessary to obtain the
desired results under applicable operating conditions can be
readily determined through routine experimentation.
[0044] The defoaming agent typically is dispersable in the other
components of the wetting composition. Examples of suitable
defoaming agents include petroleum-based antifoams (e.g.,
2-octanol, sulfonated oils, organic phosphates) and silicone-based
antifoams. However, it has been found that petroleum-based
antifoams may be susceptible to degradation in the wetting
compositions disclosed herein and may not provide the desired level
of foam mitigation during use after prolonged periods (e.g., 1 to 2
days) following formulation. Accordingly, in such embodiments, the
wetting compositions can be prepared for use in aqueous solution as
a single or one part product; or the remainder of the composition
can be packaged separately from the petroleum-based antifoam to be
combined with the remainder of the composition just prior to use at
the diesel operating site. In order to provide a wetting
composition capable of sufficient foam mitigation and longer
effective shelf-life, it is preferred that a silicone-based
antifoam be utilized as the defoaming agent. Specific examples of
silicone-based antifoams include silicone fluids and
organosiloxanes. In accordance with an especially preferred
embodiment, the defoaming agent comprises a polydimethylsiloxane.
Non-limiting examples of suitable polydimethylsiloxane antifoams
include those available from General Electric (Waterford, N.Y.),
such as those sold under the product designations AF9000, AF9010,
AF9020 and AF9030.
[0045] In one preferred embodiment wherein the chemical hydrocarbon
cleaner component comprises a nonionic surfactant comprising an
ethoxylated nonylphenol in combination with monoethanolamine or
other alkanolamine, the wetting composition may advantageously be
formulated with a tall oil fatty acid. In such an embodiment, the
tall oil fatty acid is saponified at least to some extent with the
alkanolamine caustic to form a soap.
[0046] The wetting composition of the present invention may include
a variety of optional components in addition to the chemical
hydrocarbon cleaner and the defoaming agent. For example, the
composition, particularly when a surfactant (e.g., a nonionic
surfactant) is utilized as the chemical hydrocarbon cleaner, may
further include an organic solvent. In such embodiments, the
organic solvent may provide composition thinning or fluidity, for
example, in the form of a colloid. Suitable non-limiting examples
of organic solvents include alkylene glycol ethers such as
dipropylene glycol methyl ether.
[0047] It may also be advantageous to include in the wetting
composition a coupling agent such as tetrasodium
ethylenediaminetetraacetate (EDTA) as a formulation aid.
[0048] One representative preferred wetting composition useful in
treating diesel exhaust emission gases in accordance with the
present invention comprises water; a chemical hydrocarbon cleaner
comprising ethoxylated nonylphenol nonionic surfactant and a soap
formed by saponifying a tall oil fatty acid with monoethanolamine;
an organic solvent comprising dipropylene glycol methyl ether; a
coupling agent comprising tetrasodium EDTA; and a defoaming agent
comprising a silicone-based antifoam. Preferably, the ethoxylated
nonylphenol nonionic surfactant comprises nonoxynol 10 and the
silicone-based antifoam comprises a polydimethylsiloxane.
[0049] Another more representative preferred wetting composition in
accordance with the present invention comprises at least about 35%
by weight water; a chemical hydrocarbon cleaner comprising an
ethoxylated nonylphenol nonionic surfactant and a soap formed by
saponifying a tall oil fatty acid with monoethanolamine, wherein
the composition comprises from about 10% to about 30% by weight
ethoxylated nonylphenol nonionic surfactant, from about 2% to about
8% by weight tall oil fatty acid and from about 1% to about 5% by
weight monoethanolamine; an organic solvent comprising dipropylene
glycol methyl ether, wherein the composition comprises from about
5% to about 15% by weight dipropylene glycol methyl ether; a
coupling agent comprising tetrasodium EDTA, wherein the composition
comprises at least about 0.5% by weight tetrasodium EDTA; and a
defoaming agent comprising a silicon-based antifoam, wherein the
composition comprises at least about 1% by weight silicon-based
antifoam. Preferably, the ethoxylated nonylphenol nonionic
surfactant comprises nonoxynol 10 and the silicone-based antifoam
comprises a polydimethylsiloxane.
[0050] Examples of wetting compositions in accordance with the
present invention include the products designated Aqua Filter Nos.
195D, 942D and 735D available from Brady's Mining and Construction
Supply Co. (St. Louis, Mo.). These wetting compositions each have a
multiple surfactant base of low foaming surfactants plus a
silicone-based antifoam.
[0051] Methods and techniques for formulating wetting compositions
in accordance with the present invention will be readily apparent
to those skilled in the art. Generally, water, the chemical
hydrocarbon cleaner and the defoaming agent along with any other
components of the wetting composition are blended in a suitable
vessel equipped with an agitation device (e.g., a stirred tank).
Typically, it may be necessary to heat the mixture or the
individual components thereof in order to produce the desired
composition in the form of a colloid, suspension, emulsion or
solution.
[0052] In formulating these preferred wetting compositions of the
present invention it may be useful to start with the colloidal
surfactant blend designated B/F100P, available from Foresight
Chemical (Troy, Ill.) and Brady's Mining and Construction Supply
Co. (St. Louis, Mo.). This product comprises a colloid containing
nonoxynol 10, dipropylene glycol methyl ether, monoethanolamine,
tall oil fatty acid and tetrasodium EDTA. Accordingly, B/F100P can
be used as a suitable base for formulating the wetting composition
described herein. In one embodiment, a suitable quantity of
defoaming agent (e.g., polydimethylsiloxane) may be added to
produce the wetting composition. However, in order to provide a
more effective wetting composition having desirable fluidity
characteristics, it is preferred to add additional quantities of
nonoxynol 10 and tall oil fatty acid as necessary to obtain the
desired composition as set forth above along with the defoaming
agent. Preferably the B/F100P base composition is heated to a
temperature of from about 125.degree. to about 175.degree. F.
during addition of these ingredients. Typically, additional
dipropylene glycol methyl ether is added in order to thin the
composition and ensure sufficient fluidity in the final wetting
composition. For example, in one embodiment, a suitable wetting
composition may be prepared by mixing approximately 70 parts by
weight of B/F100P with approximately 30 parts by weight of a low
foaming surfactant including approximately 10 parts by weight of a
silicone-based defoaming agent.
[0053] Although a preferred wetting composition as described above
includes an ethoxylated nonylphenol nonionic surfactant as the
chemical hydrocarbon cleaner, those skilled in the art will be able
to identify other surfactants, detergents, soaps and mixtures
thereof for use in combination with a defoaming agent. Examples of
such chemical hydrocarbon cleaners include the surfactants found in
JOY brand dishwashing liquid (Procter and Gamble, Cincinnati, Ohio)
and PALMOLIVE brand dishwashing liquid (Colgate-Palmolive, New
York, N.Y.). Suitable anionic surfactants include alkylether
sulfates, alkyl sulfates and mixtures thereof.
[0054] In accordance with the present invention, the DPM level of
the exhaust gas entering the scrubber can be reduced by at least
about 30% and the carbon monoxide loading reduced to an acceptable
level (e.g., 13 ppm). In one preferred embodiment, the DPM level
can be reduced in the range of from about 40% to about 80%. In an
even more preferred embodiment, the DPM level can be reduced by
from about 60% to about 80% or even higher levels of reduction. In
addition, up to about 99% of DPM can be removed when the water bath
scrubber (33) is used in conjunction with a final filter (43).
[0055] The scrubber tank 33 of the FIG. 2 embodiment holds a water
bath having a major water constituent (e.g., typically from about
25 to about 50 gal.) and a minor constituent amount (e.g.,
typically from about 1 to about 2 qts.) of the wetting composition
disclosed herein (e.g., a solution of about 0.5% to 2%). Clearly,
higher concentrations of the wetting composition in the water bath
will perform to attract and hold more DPM over longer operating
periods. It should be noted that flushing of the tank (33) and
replacement of the aqueous solution periodically (e.g., in the
range of about 4 to 6 hours) will be required for optimum
performance to achieve "clean air" objectives. This is a low cost,
high satisfaction result as compared with the high cost of present
prior art systems.
[0056] Referring now to FIG. 3, another form of the invention is
shown diagrammatically as an exhaust scrubber EE having a scrubber
apparatus constructed and arranged to provide a continuous water
bath replacement process. In the FIG. 3 embodiment the scrubber
tank 133 is relatively small and has a capacity for holding about 4
gallons of the aqueous solution. Similar to the FIG. 2 embodiment,
in FIG. 3 the insulated diesel exhaust pipe 135 connects from the
engine (12) to the tank 133 at a gas intake 134, and an internal
extension pipe 137 extends below the tank's water level 138 and has
a perforated gas discharge diffuser 139 for dispersing the DPM
laden exhaust gas as it is discharged into the water bath WB. The
diffuser 139 is shown as discharging exhaust gas radially,
outwardly through the water bath, but other gas dispersing means
may be arranged in the water bath. The tank 133 also has a gas
discharge outlet 142 located above the water level 138. The feature
of the FIG. 3 embodiment is that the aqueous solution of the water
bath WB has a continuous feed and is constantly flowing into and
through the tank 133 to intimately mix with exhaust gases and
remove DPM and carbon monoxide from such exhaust gases.
[0057] FIG. 3 shows that the aqueous solution can be prepared by
admixing a minor portion of super-wetting agent with a major
quantity of water as in a blending tank or mixer 170 constructed to
hold a large amount of solution, such as 45 to 55 gal. and from
which the flow rate of the water bath solution into tank 133 can be
regulated, as at 171. The super-wetting aqueous solution is
delivered into the tank through a delivery tube or pipe 172 and
discharged through a perforated distributor 173 outwardly in radial
directions to maintain level of the water bath WB, in such manner
that the exhaust gases as a first medium, are dispersed into or
throughout the water bath even as the incoming aqueous solution, as
a second medium, is being dispersed therein to achieve the desired
intimate turbulence and intermixing whereby the super-wetting agent
removes the DPM and cleans the exhaust gases. Thus, the water bath
WB of FIG. 3 is not static as the tank 133 has an outlet 174 for
regulating the out flow drainage of the aqueous solution from the
tank 133 at the predetermined rate so that the solution is
constantly flowing into and replacing the water bath content as it
is discharged from the tank.
[0058] Still referring to FIG. 3, the small volume tank 133 is
provided with the baffle means 144 extending upwardly from adjacent
the floor 146 and baffle means 145 extending down from the top of
the tank 133 to enhance circuitous gas flow paths. Through-ports
149 may also be provided in these baffles 144 to increase
turbulence and intermixing of the exhaust gases with the aqueous
solution. The baffles 145 form vapor seals above the level of the
water bath in the tank 133 to force the exhaust gas to pass through
the water bath to the exhaust.
[0059] It should be noted that the effluent solution from outlet
drain 174 can be piped off for remote disposal. However, in most
underground mining operations, as in coal mining, water is widely
used for different purposes by different equipment, and it is
usually discharged as wastewater onto the mining floor where it
will be absorbed or from which it may or may not be removed by
gravity run-off or through sump action. For instance, water is used
in drilling and cutting operations as a coolant for rotary drill
bits, long-wall cutting teeth and the like--as well as to remove
and flush cuttings away from the drilling or cutting site.
Respirable dust is a health threat even as DPM environmental air
pollution is a concern addressed by the present invention.
Therefore, water is used as a dust suppressant and the disposal
methods for effluent mine water from the various diesel systems or
other mining equipment are a general concern, but outside the scope
of the invention.
[0060] Referring to FIGS. 4 and 5, the invention can be carried out
in an exhaust scrubber apparatus (EE) having a sealed scrubber tank
jacket or housing 233 with an exhaust gas inlet 234 from diesel
exhaust pipe 235 at one side and clean gas outlet 242 at the other
side. In this embodiment the aqueous solution is discharged in a
plurality of adjacent vertical streams (280) as a continuous water
bath curtain from the top wall 247 across the width of the scrubber
tank 233 to the floor 246 from which the effluent is removed
through an outlet drain 274 for disposal. The aqueous solution
formed by mixing a super-wetting agent of the invention with water,
as in blending tank or mixer 270, is delivered through a flow
regulator 271 to a distributor manifold 281 or the like from which
it is piped to one or more horizontal perforated pipes 282. The
diffuser 239 for spreading out the discharge of exhaust gases in
the scrubber tank chamber is constructed and arranged to have a
maximum gas discharge area to provide the widest gas dispersion
through and intimate contact with the aqueous solution as it passes
through the vertical curtain wall of the water bath WB.
[0061] The aqueous solutions used in the FIG. 3 and FIG. 4
embodiments will be the same as previously discussed, and only the
respective delivery and mixing of exhaust gases therewith is
different.
[0062] It is now apparent that the objects and advantages of the
present invention have been fully met. Changes and modifications of
the disclosed forms and combinations of the invention will become
apparent to those skilled in the mining field and the providers and
operators of diesel equipment in general, and the invention is only
to be limited by the scope of the appended claims.
* * * * *