U.S. patent application number 09/865803 was filed with the patent office on 2002-12-05 for wet scrubber.
Invention is credited to Chuang, Jackson, Chuang, Johnson.
Application Number | 20020180072 09/865803 |
Document ID | / |
Family ID | 25346264 |
Filed Date | 2002-12-05 |
United States Patent
Application |
20020180072 |
Kind Code |
A1 |
Chuang, Johnson ; et
al. |
December 5, 2002 |
WET SCRUBBER
Abstract
A scrubber for removing soluble materials from harmful gaseous
effluents with high efficiency and safety is disclosed. By using
twice mixes of the scrubbing liquid and the harmful gaseous
effluent, the scrubber meets the standards of environment
protection. The scrubber of this invention also prevents the
problems of factory safety presenting in the conventional fume
scrubber. Owing to the high efficiency of the mixing of the harmful
gaseous effluent and the scrubbing liquid, the production
facilities or processing units need not stop operating once the
supply of the scrubbing liquid terminates.
Inventors: |
Chuang, Johnson; (Ta-Li
City, TW) ; Chuang, Jackson; (Ta-Li City,
TW) |
Correspondence
Address: |
POWELL, GOLDSTEIN,
FRAZER & MURPHY LLP
P.O. BOX 97223
WASHINGTON
DC
20090-7223
US
|
Family ID: |
25346264 |
Appl. No.: |
09/865803 |
Filed: |
May 29, 2001 |
Current U.S.
Class: |
261/29 ;
261/36.1; 261/97; 261/DIG.27; 261/DIG.72; 96/291; 96/296 |
Current CPC
Class: |
B01D 53/18 20130101;
Y10S 261/09 20130101 |
Class at
Publication: |
261/29 ; 96/291;
96/296; 261/97; 261/DIG.027; 261/DIG.072; 261/36.1 |
International
Class: |
B01F 003/04 |
Claims
What is claim is:
1. A scrubber for scrubbing gaseous effluents, said scrubber
comprising: a scrubbing chamber comprising: a filter region
therein, said filter region comprising: a perforate diverter; a
perforate filter under said perforate diverter; and a plurality of
filter media packed between said perforate diverter and said
perforate filter; at least two perforate plates disposed under said
perforate filter each having a plurality of openings; a scrubbing
liquid supply pipe connecting the top of said scrubbing chamber to
transit a scrubbing liquid into said scrubbing chamber from a
scrubbing liquid supply source; a first gas conduit connecting the
top of said scrubbing chamber at a first end of said first gas
conduit to exhaust said gaseous effluents from said scrubbing
chamber to a main gas discharge conduit; a manual valve connecting
a second end of said first gas conduit; a second gas conduit
connecting said manual valve at a first end of said second gas
conduit; a first pump connecting a second end of said second gas
conduit to exhaust said gaseous effluents from processing units
into said second gas conduit; a check valve connecting a third end
of said second gas conduit; a third gas conduit connecting said
check valve at a first end of said third gas conduit and the bottom
of said scrubbing chamber at a second end of said third gas conduit
to transit said gaseous effluents into said scrubbing chamber,
wherein only effluents from said second gas conduit to said third
gas conduit can pass said check valve; a recirculation pipe
connecting the bottom of said scrubbing chamber at a first end of
said recirculation pipe and the top of said scrubbing chamber at a
second end of said recirculation pipe; a second pump disposed in
the path of said recirculation pipe to exhaust said scrubbing
liquid from the bottom of said scrubbing chamber to said filter
region; a scrubbing liquid drain pipe connecting said scrubbing
chamber at a level higher than said perforate plates to drain the
excess scrubbing liquid.
2. The scrubber according to claim 1, wherein said perforate
diverter comprises a rotatable perforate plate.
3. The scrubber according to claim 1, wherein said filter media
comprise plastic packing spheroids formed of open annular
loops.
4. The scrubber according to claim 1, wherein said perforate plates
are disposed in sequence of opening size so that said perforate
plate having the smallest openings is disposed at the highest
level.
5. The scrubber according to claim 1, wherein said perforate plates
comprise acid-resisting perforate plates.
6. The scrubber according to claim 1, wherein said first pump
comprises a dry pump.
7. The scrubber according to claim 1, wherein said scrubbing liquid
comprises tap water.
8. A scrubber for scrubbing gaseous effluents, said scrubber
comprising: a scrubbing chamber comprising: a filter region
therein, said filter region comprising: a perforate diverter; a
perforate filter under said perforate diverter; and a plurality of
filter media packed between said perforate diverter and said
perforate filter; at least two perforate plates disposed under said
perforate filter each having a plurality of openings; a scrubbing
liquid supply pipe connecting the top of said scrubbing chamber to
transit tap water into said scrubbing chamber from a tap water
supply source; a first gas conduit connecting the top of said
scrubbing chamber at a first end of said first gas conduit to
exhaust said gaseous effluents from said scrubbing chamber to a
main gas discharge conduit; a manual valve connecting a second end
of said first gas conduit; a second gas conduit connecting said
manual valve at a first end of said second gas conduit; a first
pump connecting a second end of said second gas conduit to exhaust
said gaseous effluents from processing units into said second gas
conduit; a check valve connecting a third end of said second gas
conduit; a third gas conduit connecting said check valve at a first
end of said third gas conduit and the bottom of said scrubbing
chamber at a second end of said third gas conduit to transit said
gaseous effluents into said scrubbing chamber, and having a purge
conduit to transit a purge gas, wherein only effluents from said
second gas conduit to said third gas conduit can pass said check
valve; a recirculation pipe connecting the bottom of said scrubbing
chamber at a first end of said recirculation pipe and the top of
said scrubbing chamber at a second end of said recirculation pipe;
a second pump disposed in the path of said recirculation pipe to
exhaust said tap water from the bottom of said scrubbing chamber to
said filter region; a scrubbing liquid drain pipe connecting said
scrubbing chamber at a level higher than said perforate plates to
drain the excess tap water.
9. The scrubber according to claim 8, wherein said perforate
diverter comprises a rotatable perforate plate.
10. The scrubber according to claim 8, wherein said filter media
comprise plastic packing spheroids formed of open annular
loops.
11. The scrubber according to claim 8, wherein said perforate
plates are disposed in sequence of opening size so that said
perforate plate having the smallest openings is disposed at the
highest level.
12. The scrubber according to claim 8, wherein said perforate
plates comprise acid-resisting perforate plates.
13. The scrubber according to claim 8, wherein said first pump
comprises a dry pump.
14. The scrubber according to claim 8, wherein said purge gas
comprises nitrogen gas.
15. A scrubber for scrubbing gaseous effluents, said scrubber
comprising: a scrubbing chamber comprising: a filter region
therein, said filter region comprising: a perforate diverter; a
perforate filter under said perforate diverter; and a plurality of
filter media packed between said perforate diverter and said
perforate filter; at least two perforate plates each having a
plurality of openings disposed in sequence of opening size and
under said perforate filter, wherein said perforate plate having
the smallest openings is disposed at the highest level; a scrubbing
liquid supply pipe connecting the top of said scrubbing chamber to
transit tap water into said scrubbing chamber from a tap water
supply source; a first gas conduit connecting the top of said
scrubbing chamber at a first end of said first gas conduit to
exhaust said gaseous effluents from said scrubbing chamber to a
main gas discharge conduit; a manual valve connecting a second end
of said first gas conduit; a second gas conduit connecting said
manual valve at a first end of said second gas conduit; a first
pump connecting a second end of said second gas conduit to exhaust
said gaseous effluents from processing units into said second gas
conduit; a check valve connecting a third end of said second gas
conduit; a third gas conduit connecting said check valve at a first
end of said third gas conduit and the bottom of said scrubbing
chamber at a second end of said third gas conduit to transit said
gaseous effluents into said scrubbing chamber, and having a purge
conduit used to transit a purge gas, wherein only effluents from
said second gas conduit to said third gas conduit can pass said
check valve; a recirculation pipe connecting the bottom of said
scrubbing chamber at a first end of said recirculation pipe and the
top of said scrubbing chamber at a second end of said recirculation
pipe; a second pump disposed in the path of said recirculation pipe
to exhaust said tap water from the bottom of said scrubbing chamber
to said filter region; a scrubbing liquid drain pipe connecting
said scrubbing chamber at a level higher than said perforate plates
to drain the excess tap water.
16. The scrubber according to claim 15, wherein said perforate
diverter comprises a rotatable perforate plate.
17. The scrubber according to claim 15, wherein said filter media
comprise plastic packing spheroids formed of open annular
loops.
18. The scrubber according to claim 15, wherein said perforate
plates comprise acid-resisting perforate plates.
19. The scrubber according to claim 15, wherein said first pump
comprises a dry pump.
20. The scrubber according to claim 15, wherein said purge gas
comprises nitrogen gas.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a scrubber for removing
soluble materials from toxic gases, and more particularly to a
scrubber for removing soluble materials from harmful gaseous
effluents with high efficiency and safety.
[0003] 2. Description of the Related Art
[0004] Semiconductor manufacturing facilities utilize chemical
vapor deposition, etching and a wide variety of other unit
operations in the fabrication of modern semiconductor devices using
process gases such as SF.sub.6, SiCl.sub.4, SiH.sub.2Cl.sub.2, and
WF.sub.6. The gaseous effluent from processing units in such
facilities comprise the unconsumed process gases, as well as
by-products of such gases. The gaseous effluent additionally may
contain significant quantities of particulates such as silica,
which must be removed, in addition to various water soluble
components such as hydrochloric acid and residuals of phosphine and
arsine.
[0005] Water scrubbing is commonly used to remove such particulates
and water-soluble gases from the process effluent stream. In such
scrubbing, the effluent gas is intimately contacted with water,
e.g., by passage of the gaseous effluent through a water spray, to
dissolve the soluble gas components and wet and thereby remove the
particulates. The scrubbing liquid may then be filtered, to remove
the scrubbed particulates from the scrubbing medium. The water
scrubber unit typically is deployed immediately upstream of a bulk
exhaust for the entire plant facility, and is used to treat the
process facility effluent, which may vary considerably in
concentration of water-soluble components and particulates,
depending on the specific types of semiconductor devices or
subassembly parts which are being manufactured, and the resulting
"mix" of unit operations being carried out in the process
facility.
[0006] FIG. 1A shows a conventional fume scrubber 100. As shown in
FIG. 1A, a scrubbing chamber 110 having a filter region 120 therein
is shown. The filter region 120 comprises an upper perforate
diverter plate 122 and a lower perforate plate 124. A plurality of
filter media 126 are packed into the filter region 120 and between
the perforate diverter plate 122 and the perforate plate 124. The
detail structure of the filter media 126 is shown in FIG. 1B and
the filter media 126 is comprised of plastic packing spheroids
formed of open annular loops as shown in the figure. In the top of
the scrubbing chamber 110, there are a gas inlet 112a, an opening
112b, fluid inlets 114a and 114b. A dry exhaust pump 152 exhausts
the gaseous effluent from processing units to the scrubbing chamber
110 through a gas exhaust conduit 132 connecting the gas inlet
112a. An N.sub.2 purge conduit 133 is connected to the gas exhaust
conduit 132. A gas discharge conduit 134 connecting to a main gas
discharge conduit (not shown) is through the top of the scrubbing
chamber 110 and the filter region 120 by the opening 112b. The gas
discharge conduit 134 has a gas inlet 135 with a tilt opening under
the perforate plate 124. A tap water supply pipe 136 connects the
scrubbing chamber 110 by the fluid inlets 114a. There are also a
fluid outlet 116a and an opening 116b on the bottom of the
scrubbing chamber 110 as shown in FIG. 1A. A recirculation pump 154
exhausts the scrubbing water from the bottom of the scrubbing
chamber 110 back to the filter region 120 via a recirculation pipe
138. The two ends of the recirculation pipe 138 individually
connect the scrubbing chamber 110 at the fluid inlets 114b and the
fluid outlet 116a. An over flow drain pipe 140 used to drain excess
scrubbing water is disposed through the bottom of the scrubbing
chamber 110 by the opening 116b, and the over flow drain pipe 140
has a fluid outlet 142 used to drain the excess scrubbing
water.
[0007] In the operation of the conventional fume scrubber 100, the
gaseous effluent from processing units is exhausted through the gas
exhaust conduit 132 into the scrubbing chamber 110 by the dry
exhaust pump 152, wherein the N.sub.2 purge conduit 133 provides
dry N.sub.2 gas to exclude moisture so that less contamination or
clump of particulates will precipitate. The gaseous effluent passes
the filter region 120 and contacts with the tap water from the tap
water supply pipe 136, and the water-soluble gas components will
solve in the tap water. Owing to the open annular loops of the
filter media 126, the water-soluble gas components will solve in
the tap water flowing along the open annular loops more
effectively. After contacting and adsorbing the gas components, the
tap water transfers to scrubbing water and flows to the bottom of
the scrubbing chamber 110. The scrubbing water accumulates at the
bottom of the scrubbing chamber 110 until the scrubbing water
surface reaches the fluid outlet 142, and the excess scrubbing
water will be drain through the over flow drain pipe 140 to a main
drain pipe which is not shown in FIG. 1A. The scrubbing water also
will be exhausted through the recirculation pipe 138 back to the
filter region 120 by the recirculation pump 154. The scrubbing
water will remix with the gaseous effluent through the
recirculation cycle set forth. After passing the filter region 120
and mixing with the tap water and the scrubbing water, the gaseous
effluent will be exhausted through the gas discharge conduit 134 to
the main gas discharge conduit (not shown).
[0008] However, it is found that the drawbacks of the conventional
fume scrubber 100 present environment protection issues and
production facility malfunctions, and even result in factory safety
problems. For example, the scrubbing water is usually exhausted
together with the gaseous effluent through the gas discharge
conduit 134 to the main gas discharge conduit (not shown) after
passing the filter region 120 thereby results in the pump
malfunctions of the production facilities connected to the main gas
discharge conduit and even causes serious factory safety problems.
Furthermore, the mixing efficiency of the gaseous effluent with the
tap water and the scrubbing water is not satisfactory and the
environment protection issues will arise from the interruption of
the tap water, and thus the production facilities must be shut
down. In view of the drawbacks mentioned above, it is desirable to
provide an advance scrubber that can prevent the problems of the
conventional fume scrubber set forth, it is toward these goals that
this invention specially directs.
SUMMARY OF THE INVENTION
[0009] It is therefore an object of the invention to provide an
advance scrubber having high recirculation efficiency of the
harmful gaseous effluent.
[0010] It is another object of this invention to provide an advance
scrubber which can meet the standards of environment protection and
the requirements of factory safety.
[0011] It is a further object of this invention to provide a
reliable scrubber for removing soluble materials from harmful
gaseous effluents with high efficiency and safety.
[0012] It is another object of this invention to provide an advance
scrubber which renders the production facilities or processing
units continually operating as the supply of the scrubbing liquid
terminates.
[0013] To achieve these objects, and in accordance with the purpose
of the invention, a scrubber of the invention for scrubbing gaseous
effluents by a scrubbing liquid is provided. The scrubber comprises
a scrubbing chamber, a first gas conduit connecting the top of said
scrubbing chamber, a manual valve, a second gas conduit connecting
said first gas conduit by said manual valve, a gas exhaust pump
exhausting a gaseous effluent to said second gas conduit, a check
valve, a third gas conduit having a purge conduit used to transit a
purge gas, said third gas conduit connecting said second gas
conduit by said check valve, said third gas conduit connecting the
bottom of said scrubbing chamber to transit said gaseous effluent
into said scrubbing chamber, wherein only effluents from said
second gas conduit to said third gas conduit can pass said check
valve, a scrubbing liquid supply pipe used to transit a scrubbing
liquid into said scrubbing chamber connecting the top of said
scrubbing chamber, a recirculation pump used to exhaust said
scrubbing liquid connecting the bottom of said scrubbing chamber, a
recirculation pipe used to recirculate said scrubbing liquid
connecting said recirculation pump and the top of said scrubbing
chamber, and a scrubbing liquid drain pipe connecting said
scrubbing chamber at a level higher than said perforate plates. The
scrubbing chamber further comprises a filter region therein and at
least two perforate plates disposed in sequence and under said
perforate filter. The filter region comprises a perforate diverter,
a perforate filter under said perforate diverter and a plurality of
filter media packed between said perforate diverter and said
perforate filter.
[0014] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory only and are not restrictive of the invention, as
claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] 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:
[0016] FIG. 1A shows a schematic diagram of a conventional fume
scrubber;
[0017] FIG. 1B shows a schematic diagram of a filter medium;
[0018] FIG. 2A shows a schematic diagram of a scrubber of this
invention;
[0019] FIG. 2B shows openings of the upper perforate plate; and
[0020] FIG. 2C shows openings of the lower perforate plate.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] The present invention can be practiced in conjunction with
various techniques that are used in the art, and only so much of
the commonly used structures and operation steps are included
herein as are necessary to provide an understanding of the present
invention. The present invention will be described in detail with
reference to the accompanying drawings. It should be noted that the
drawings are in greatly simplified form and they are not drawn to
scale. Moreover, dimensions have been exaggerated in order to
provide a clear illustration and understanding of the present
invention.
[0022] Referring to FIG. 2A, a scrubber 200 of this invention is
shown. As shown in FIG. 2A, a scrubbing chamber 210 having a filter
region 220 therein is shown. The filter region 220 comprises a
perforate diverter 222 and a perforate filter 224. The perforate
diverter 222 and the perforate filter 224 preferably comprise, but
are limited to: a rotatable perforate plate and a perforate filter
plate. Furthermore, the rotatable perforate plate and the perforate
filter plate are made of acid-resisting materials. The perforate
diverter 222 is used to divert or spread liquid came from above. A
plurality of filter media 229 are packed into the filter region 220
and between the perforate diverter 222 and the perforate filter
224. The filter media 229 preferably comprise filter media as shown
in FIG. 1B. The detail structure of the filter media is shown in
FIG. 1B. The filter media are comprised of plastic packing
spheroids formed of open annular loops as shown in the figure.
[0023] Two perforate plates 226a and 226b are disposed in the
scrubbing chamber 210 and under the filter region 220. The
perforate plates 226a and 226b preferably comprise perforate plates
made of acid-resisting materials. Moreover, the perforate plates
226a and 226b preferably have openings 228a and 228b separately
shown in FIG. 2B and FIG. 2C. The opening 228a of the perforate
plates 226a has a size smaller than the size of the opening 228b of
the perforate plate 226b. The size of the opening 228a, for
example, can be about 1 centimeter. The opening 228b can has a size
of about 3 centimeter. It is noted that there can be more than two
perforate plates similar to the perforate plates 226a and 226b
disposed in the scrubbing chamber 210 and under the filter region
220. Each of the perforate plates disposed has a size of openings
which is different from the sizes of openings of other perforate
plates, and the perforate plates are disposed in sequence of
opening size so that the perforate plate having the smallest
openings is disposed at the highest level or a position nearest the
filter region 220.
[0024] In the top of the scrubbing chamber 210, there are a gas
outlet 212, fluid inlets 214a and 214b. In the bottom of the
scrubbing chamber 210, there are a fluid outlet 216a and an
effluent inlet 218. A pump comprising a gas exhaust pump 252
exhausts gaseous effluents from processing units to the bottom of
the scrubbing chamber 210 through a gas conduit 232, a check valve
262 and a gas conduit 236 as shown in FIG. 2A. The flow path of the
gaseous effluent set forth is the main gaseous effluent flow path
of this invention. The gas conduit 236 further comprises a purge
conduit 237 used to introduce a purge gas such as N.sub.2 gas.
There is a bypass comprising the gas conduit 232, a manual valve
264 and a gas conduit 234 disposed on the top of the scrubbing
chamber 210 connecting the gas outlet 212 to a main gas discharge
pipe which is not shown. A scrubbing liquid supply pipe 242 used to
transit a scrubbing liquid preferably comprising tap water into the
scrubbing chamber 210 connects the fluid inlets 214a to a scrubbing
liquid supply source which is not shown. A recirculation pipe 238
connecting the fluid inlet 214b and the fluid outlet 216a is used
to recirculate the scrubbing liquid supplied via the scrubbing
liquid supply pipe 242 from the bottom of the scrubbing chamber-210
back to the filter region 220. This is done by a pump 254
comprising a recirculation pump exhausting the scrubbing liquid. A
scrubbing liquid drain pipe 240 connecting a fluid outlet 216b of
the scrubbing chamber 210 to a main liquid drain pipe (not shown)
is also shown in FIG. 2A. The scrubbing liquid drain pipe 240 is
used to drain the excess scrubbing liquid. The fluid outlet 216b is
located on a sidewall of the scrubbing chamber 210 and at a level
higher than the perforate plate 226a or the highest perforate
plate.
[0025] In the operation of the scrubber 200, the gaseous effluent
from the processing units is exhausted to the gas conduit 232 by
the pump 252 comprising a gas exhaust pump. The gaseous effluent
then passes the check valve 262 to the gas conduit 236. The manual
valve 264 is closed in normal operation condition. The gaseous
effluent next enters the scrubbing chamber 210 through the gas
conduit 236, meanwhile, a scrubbing liquid such as tap water flows
into the scrubbing chamber 210 via the scrubbing liquid supply pipe
242. As the gaseous effluent continues flowing into the scrubbing
chamber 210 via the main flow path set forth, the scrubbing liquid
will accumulate at the bottom of the scrubbing chamber 210. Because
the gas conduit 236 connects the bottom of the scrubbing chamber
210, the scrubbing liquid will flow into the gas conduit 236, but
the scrubbing liquid will be blocked by the check valve 262 so that
the scrubbing liquid will not flow into the gas conduit 232. The
gas effluent passing through the check valve 262 will contact and
sufficiently mix with the scrubbing liquid so that most of the
soluble components of the gas effluent will solve in the scrubbing
water. In case of formation of bubbles which are obstacles to the
solution of the soluble components in the scrubbing liquid, the
perforate plates 226a and 226b having well-distributed openings are
used. To eliminate the bubbles effectively, more than two perforate
plates could be uitilized. Each of the perforate plates disposed in
sequence has a size of openings which is different from the sizes
of openings of other perforate plates, and the perforate plates are
disposed in sequence of opening size so that the perforate plate
having the smallest openings is disposed at the highest level or
nearest the filter region 220. The gaseous effluent passing through
the perforate plates 226a and 226b and leaving the scrubbing liquid
surface then are exhausted to the main gas discharge conduit (not
shown) through the filter region 220 and the gas conduit 234. The
gaseous effluent will contact and remix with the scrubbing liquid
flew through the filter media 229 of the filter region 220.
Moreover, the scrubbing liquid accumulated on the bottom of the
scrubbing chamber 210 will be exhausted back to the filter region
220 through the recirculation pipe 238 by the pump 254.
[0026] The scrubber of this invention provide a high recirculation
efficiency of the harmful gaseous effluent and via twice mixes of
the scrubbing liquid and the harmful gaseous effluent so that the
standards of environment protection will be met. Furthermore, the
scrubber of this invention prevents the problems of factory safety
presenting in the conventional fume scrubber. Owing to the high
efficiency of the mixing of the harmful gaseous effluent and the
scrubbing liquid, the production facilities or processing units
need not stop operating as the supply of the scrubbing liquid
terminates.
[0027] Other embodiments of the invention will appear to those
skilled in the art from consideration of the specification and
practice of the invention disclosed herein. It is intended that the
specification and examples to be considered as exemplary only, with
a true scope and spirit of the invention being indicated by the
following claims.
* * * * *