US3741235A - Washing and purging apparatus for liquid seals - Google Patents

Washing and purging apparatus for liquid seals Download PDF

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Publication number
US3741235A
US3741235A US00214009A US3741235DA US3741235A US 3741235 A US3741235 A US 3741235A US 00214009 A US00214009 A US 00214009A US 3741235D A US3741235D A US 3741235DA US 3741235 A US3741235 A US 3741235A
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US
United States
Prior art keywords
seal
liquid
nozzles
drain
overflow
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00214009A
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English (en)
Inventor
A Ambrose
J Parker
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Combustion Engineering Inc
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Combustion Engineering Inc
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Publication date
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Publication of US3741235A publication Critical patent/US3741235A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
    • F16K13/00—Other constructional types of cut-off apparatus; Arrangements for cutting-off
    • F16K13/08—Arrangements for cutting-off not used
    • F16K13/10—Arrangements for cutting-off not used by means of liquid or granular medium
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/4238—With cleaner, lubrication added to fluid or liquid sealing at valve interface
    • Y10T137/4245—Cleaning or steam sterilizing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/4456—With liquid valves or liquid trap seals
    • Y10T137/4463—Liquid seal in liquid flow line; flow liquid forms seal
    • Y10T137/4516—Seal replenishers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/4456—With liquid valves or liquid trap seals
    • Y10T137/4643—Liquid valves
    • Y10T137/4658—With auxiliary means for varying liquid level

Definitions

  • ABSTRACT A washing and purging system for a liquid seal in the flue gas bypass duct of a steam generating facility having an air pollution control system.
  • a series of nozzles positioned within the seal provide a continuous turnover of liquid and are also periodically used to flush accumulated particulate matter from the seal. Disposal of excess liquid from the seal is accomplished through the use of an overflowweir which also serves to skim off surface contaminant particles before they can settle to the bottom of the seal.
  • dust and fume laden gases exit the boiler through an air preheater and continue through ducts to the scrubber where the washing and cleaning of the gas is accomplished.
  • the clean gas then exits from the scrubber and continues through additional ductwork and a booster fan to the stack where it is emitted to the atmosphere.
  • coal-fired steam generating furnaces have the ability to burn fuels other than coal such as low sulfur oil or gas.
  • auxiliary fuels do not produce the high level of contaminants and particulate matter which result from the burning of coal and thus permit the boiler units to be operated without the scrubber units on the line. This is accomplished by providing a bypass duct around the scrubber which provides a path directly to the booster fan and the stack.
  • the herein provided invention involves a washing and purging system for a water seal located in a hot gas bypass duct.
  • a series of nozzles is located in the bottom of the seal.
  • Overflow weirs,'communicating with overflow discharge means, are provided at the desired liquid level of the seal.
  • a constant supply of relatively alkaline water is introduced into the seal by less than the full complement of nozzles.
  • This water effects a continuous purge of the seal water and provides a three-fold advantage: (1) the pH' of the seal water is kept at a non-corrosive level, (2) potential loss of the water seal due to water evaporation or level control malfunction is eliminated, and (3) excess water passing from the seal over the overflow weir takes with it surface particulate contaminants before they can settle.
  • a periodic cleaning operation is performed to remove accumulated particulate matter from the bottom of the seal. This is achieved by activating the entire complement of nozzles and opening the drain connection provided in the bottom of the seal.
  • the seal bottom is inclined with the drain connection at the lower end thereof and the nozzles are so arranged to effect a sluicing operation to guide the accumulated matter through the drains.
  • a distinct advantage of this cleaning operation is that it may be carried out without requiring the water seal to be broken.
  • FIG. 1 is a schematic side elevational view, partly in section, of an air pollution control system having a wet scrubber bypass duct water seal which has the washing and purging features of this invention
  • FIG. 2 is an enlarged view, partlyin section, of the water seal of FIG. 1;
  • FIG. 3 is a sectional view taken on lines 3-3 of FIG.
  • FIG. 4 is a sectional view taken on lines 4-4 of FIG. 2;
  • FIG. 5 is a partial view, similar to FIG. 3, showing one end of a seal having an overflow collector in accordance with a further embodiment of the invention.
  • FIG. 1 there is illustrated a steam generating boiler 10 having a pollution control system including wet scrubber 12 for cleansing flue gases prior to passage to the atmosphere.
  • a flue gas scrubber bypass 14 having a water seal 16 is provided to circumvent the scrubber when desired.
  • contaminated flue gases produced in the furnace 18 pass into an appropriate duct 20 through an air preheater 22 and into an inlet duct 24 to the wet scrubber 12.
  • the inlet duct 24 has a damper 26 arrangement located therein for selectively opening and closing the duct to the passage of flue gases. Gases passing into the wet scrubber 12 are cleansed of gaseous and particulate contaminants in a well-known manner not forming a part of this invention.
  • the cleansed flue gases pass from the scrubber 12 through a scrubber outlet duct 28.
  • a scrubber outlet duct 28 Located in the outlet duct 28 is a stack gas reheater 30 to minimize steam plume formation and a damper assembly 34 for selectively controlling the passage of gases therethrough.
  • Communicating with the outlet duct 28 is an appropriate exit duct 36 which in turn communicates with the inlet of induced draft fan 38.
  • the fan 38 creates a sufficient pressure differential to insure positive passage of the gases throughthe ductwork and scrubber into the stack 40 for passage to the atmosphere.
  • the flue gas scrubber bypass 14 includes a first conduit 42 communicating with the scrubber inlet duct 24 upstream of the scrubber inlet damper arrangement 26.
  • a second conduit 44 communicates at one end with the first conduit 42 and at the other end with the scrubber outlet duct 28 at a location downstream of the outlet damper 34.
  • the passage of gases from the first conduit 42 to the second conduit 44 is selectively controlled by the level of water in the water seal 16.
  • the water seal 16 includes a first plenum chamber 46 and a second plenum chamber 48 communicating with the first conduit 42 andthe second conduit 44, respectively.
  • the plenum chambers 46, 48 are fabricated from appropriate ducting material and have a common bottom plate 50 which is angularly disposed from the horizontal.
  • the plenum chambers 46, 48 are separated by a vertical baffle plate 52 originating at the junction of the upper walls of the first and second bypass conduits 42, 44 and terminating at a level spaced from the inclined bottom 50 to define a horizontal passageway interconnecting the two chambers.
  • two drain connections 54, 56 Located in the lower end of the ducting forming the front of the seal are two drain connections 54, 56 which are selectively operable to opened and closed position by means of conventional valve arrangements 58, 60.
  • a network of water pipes 67 communicating through valve arrangements, which will be subsequently further described, to a water supply 64 and adapted to distribute water to a plurality of water nozzles, 66a-f, 68a-f, extending through the bottom plate and which are directed substantially parallel to the bottom and toward the drain connections 54, 56 adjacent the lowerend of the bottom.
  • a separate series of nozzles is associated with each drain connection. The nozzles are so arranged that the number of nozzles per unit area of the bottom plate becomes increasingly greater as the lower end of the plate is approached.
  • a portion of the nozzles in each series are disposed in pairs 66c-f, 68c-f laterally offset on opposite sides of and angularly directed toward their associated drain connections.
  • valve arrangement interconnecting the water supply 64 and the nozzles 66, 68 comprises a main shutoff valve 70 and a flush valve 72.
  • the shutoff valve 70 directly controls the water supply to one pair of replenishing nozzles 66c, 680 in each series and to the flush valve 72 which in turn controls the supply to the piping 67 communicating with the remainder of the nozzles.
  • overflow collectors 74 having open upper ends defining generally horizontal upper edges 76. These collectors are positioned so that their upper edges 76 are substantially coincident with the desired normal water level of the seal when it is filled to provide a gas tight seal. Openings 78 are provided in the seal walls for communicating the interior of each collector 74, at the lower end thereof, to discharge pipes 80 extending to the exterior of the seal. The discharge pipes 80 in turn communicate with appropriate conduits 82 which terminate, at a point below the level of the water in the seal, in settling tank or pond 84 of a size capable of handling the overflow liquid.
  • the pond 84 serves as a second liquid seal to insure that atmospheric air is not drawn into plenum 46 through the discharge conduits 82. Such an occurrence would otherwise be probable because the pressure within plenum 46 is less than atmospheric, due to the sucking action of the fan 38.
  • the furnace burns a fuel such as coal which yields a highly contaminated product of combustion gases which must be passed through the scrubber 12 before being released to the atmosphere.
  • the scrubber dampers 26, 34 are opened and the water seal 16 in the bypass 14 is filled to insure that no contaminated gases are permitted to bypass the scrubber 12. Filling of the water seal is accomplished by opening both the main supply valve and the flush valve 72, water is thus caused to flow into the seal through the full complement of nozzles 66a-f, 68a-f.
  • the seal is effective to prevent the passage of flue gases therethrough.
  • the flush valve 72 When the water level in the seal reaches the horizontal upper edge 76 of the overflow collectors the flush valve 72 is moved to its closed position. Only the replenishing nozzles 66c, 680, located generally midway along the length of the inclined bottom, are now feeding water into the seal. These nozzles 66c, 68c are supplied with water continuously whenever the seal is in use. The water fed into the seal'b'y these nozzles serves two primary purposes. The first is to provide a replenishing of the water in the seal at a rate sufficient to avoid the creation of corrosive conditions in the seal. This is accomplished by making the supply water of a sufficiently alkaline nature to maintain the body of water in the seal in a substantially neutral condition.
  • the second primary purpose of the supply of water is to maintain a continuous flow of water over the upper edges 76 of the overflow collectors 74.
  • This constant overflow results in a skimming off of the surface water in the seal.
  • There is contained in this surface water a high concentration of particulate matter from the gas in the inlet plenum of the seal which has contacted and adhered to the water surface but has not. yet settled to the bottom of the seal. By skimming off this surface water this particulate matter is thereby removed.
  • an additional embodiment of an overflow collector is shown.
  • a horizontal slot 86 is provided in the seal wall, the lower edge thereof being substantially coincident with the desired normal liquid level.
  • a fully enclosed overflow collector 88 is attached to the outside wall of the seal to completely surround the horizontal slot 86.
  • the collector 88 has a discharge pipe 90, similar to that of the preferred embodiment, attached to an opening in the lower end thereof for carrying off water which has passed into the collector through the slot.
  • a liquid seal for preventing the flow of a contaminated hot gas through a conduit, the seal having a first duct means communicating with a gas supply conduit and defining a first plenum chamber, a second duct means communicating with a gas'exhaust conduit and defining a second plenum chamber, said first and second duct means cooperating to define a generally horizontal passageway interconnecting said first and second plenum chambers at the lower ends thereof and means for admitting a liquid into said seal to a level completely immersing said passageway, the improvement which comprises:
  • drain means disposed in the lower portion of said duct means adjacent the lower end of said inclined bottom plate, said drain being selectively operable to an open or closed position to drain liquid from or retain liquid in said seal respectively;
  • d. means for selectively supplying a liquid to said nozzles at a flow rate sufficient to maintain the normal liquid level in said seal when said drain means is in an open position; whereby when said liquid seal is filled to its normal level, said drain means is actuated to an open position, and said nozzle supply means is operating, a sluicing operation is performed on the inclined bottom plate of said liquid seal without requiring the gas tight seal to be broken.
  • each drain means has at least one series of nozzles associated exclusively therewith.
  • an overflow collector attached to said first duct means and having an overflow discharge opening in the lower end thereof;
  • liquid discharge means communicating with said overflow discharge opening to carry overflow liquid to an appropriate disposal point exterior of said seal;
  • liquid overflow means defining a generally horizontal upper edge for communicating the interior of said seal adjacent the desired liquid level to the interior of said overflow collector;
  • said means for continuously replenishing the liquid in the seal comprises at least one of said nozzles, said nozzle being adapted to selectively provide continuous liquid flow to said seal.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Treating Waste Gases (AREA)
  • Chimneys And Flues (AREA)
  • Cleaning In General (AREA)
  • Gas Separation By Absorption (AREA)
US00214009A 1971-12-30 1971-12-30 Washing and purging apparatus for liquid seals Expired - Lifetime US3741235A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US21400971A 1971-12-30 1971-12-30

Publications (1)

Publication Number Publication Date
US3741235A true US3741235A (en) 1973-06-26

Family

ID=22797422

Family Applications (1)

Application Number Title Priority Date Filing Date
US00214009A Expired - Lifetime US3741235A (en) 1971-12-30 1971-12-30 Washing and purging apparatus for liquid seals

Country Status (11)

Country Link
US (1) US3741235A (de)
JP (1) JPS5038807B2 (de)
BE (1) BE793520A (de)
CA (1) CA967073A (de)
DE (1) DE2263389C3 (de)
ES (1) ES410129A1 (de)
FR (1) FR2167178A5 (de)
GB (1) GB1418657A (de)
IT (1) IT972651B (de)
NL (1) NL7217849A (de)
YU (1) YU34220B (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4024881A (en) * 1976-01-22 1977-05-24 Environment Improvement Systems, Inc. Apparatus for removing gelatinous sludge and solids from settling basins
US4193967A (en) * 1978-10-16 1980-03-18 Merichem Company Liquid sealing apparatus for sealing vapors in a tank
US4326556A (en) * 1979-03-08 1982-04-27 Waagner-Biro Aktiengesellschaft Apparatus for sealing the periphery of an opening
US4411286A (en) * 1980-03-06 1983-10-25 Peabody Holmes Limited Liquid seal valve
US4913819A (en) * 1987-08-28 1990-04-03 Atlantic Richfield Company Liquid jet solids removal system for process vessels
WO1990012200A1 (en) * 1989-04-04 1990-10-18 Henry Filters, Inc. Removable flushing system for machine tool coolant return system flumes
US5205307A (en) * 1992-02-28 1993-04-27 American Polychemical Manufacturing Corp. System for cleaning contaminants from parts
US5209846A (en) * 1990-11-15 1993-05-11 Metallgesellschaft Aktiengesellschaft Filter vessel provided with a rinsing trough
US20090101571A1 (en) * 2007-10-19 2009-04-23 Kapicki Melvin D Drilling fluids settling tank

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57142883A (en) * 1981-02-14 1982-09-03 Matsushita Electric Works Ltd Supply tank for liquid raw material
JP2763245B2 (ja) * 1993-03-17 1998-06-11 日本碍子株式会社 緊急時用排ガス逃し装置

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4024881A (en) * 1976-01-22 1977-05-24 Environment Improvement Systems, Inc. Apparatus for removing gelatinous sludge and solids from settling basins
US4193967A (en) * 1978-10-16 1980-03-18 Merichem Company Liquid sealing apparatus for sealing vapors in a tank
US4326556A (en) * 1979-03-08 1982-04-27 Waagner-Biro Aktiengesellschaft Apparatus for sealing the periphery of an opening
US4411286A (en) * 1980-03-06 1983-10-25 Peabody Holmes Limited Liquid seal valve
US4913819A (en) * 1987-08-28 1990-04-03 Atlantic Richfield Company Liquid jet solids removal system for process vessels
WO1990012200A1 (en) * 1989-04-04 1990-10-18 Henry Filters, Inc. Removable flushing system for machine tool coolant return system flumes
US5209846A (en) * 1990-11-15 1993-05-11 Metallgesellschaft Aktiengesellschaft Filter vessel provided with a rinsing trough
US5205307A (en) * 1992-02-28 1993-04-27 American Polychemical Manufacturing Corp. System for cleaning contaminants from parts
US20090101571A1 (en) * 2007-10-19 2009-04-23 Kapicki Melvin D Drilling fluids settling tank

Also Published As

Publication number Publication date
YU326572A (en) 1978-09-18
GB1418657A (en) 1975-12-24
FR2167178A5 (de) 1973-08-17
IT972651B (it) 1974-05-31
DE2263389B2 (de) 1974-05-30
CA967073A (en) 1975-05-06
DE2263389A1 (de) 1973-07-12
NL7217849A (de) 1973-07-03
YU34220B (en) 1979-02-28
DE2263389C3 (de) 1975-01-23
JPS5038807B2 (de) 1975-12-12
BE793520A (fr) 1973-04-16
JPS4873833A (de) 1973-10-05
ES410129A1 (es) 1976-08-01

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