US3730499A

US3730499A - Damper-rod scrubber

Info

Publication number: US3730499A
Application number: US00164762A
Authority: US
Inventors: J Jonakin
Original assignee: Combustion Engineering Inc
Current assignee: Combustion Engineering Inc
Priority date: 1971-07-21
Filing date: 1971-07-21
Publication date: 1973-05-01
Anticipated expiration: 1990-05-01
Also published as: JPS5010028B1; FR2146423A1; CA973799A; FR2146423B1; SE387055B; DE2228039A1; DE2228039B2; ES404890A1; GB1362620A

Abstract

A wet scrubber having spray means for spraying a liquid into a passageway, and a rod scrubber positioned downstream of the spray means by which impurities can be removed from the gas stream. The rods of the scrubber are rotatably mounted, so that they can be rotated to a position parallel to the gas flow when it is desired. The rods are removably attached, so that they can be readily replaced if the need arises.

Description

Waited States Eatent 91 Jonakin [4 May I1, 973

[54] DAMPER-ROD SCRUBBER [75] Inventor: James Jonakin, Simsbury, Conn.

[73] Assignee: Combustion Engineering Inc., Windsor, Conn.

[22] Filed: July 21,1971

[21] Appl. No.: 164,762

[52] US. Cl. ..261/109, 55/226, 55/230, 55/241, 261/111 [51] Int. Cl. ..B01f 3/04 [58] Field of Search ..55/233, 257, 226, 55/230, 240, 241; 261/1 1 1, 112, 108, 109, 83

[56] References Cited UNITED STATES PATENTS 3,348,825 10/1967 Mcllvaine ..55/257 X 3,488,039 l/197O Ekman ..55/241 X 3,522,000 7/1970 Kinney ..261/1 ll X 3,544,087 12/1970 Mcllvaine 55/233 X 3,680,282 8/1972 Kent ..55/233 Primary ExaminerTim R. Miles Assistant Examiner-Richard L. Chiesa Attorney-Carlton F. Bryant et al.

[ ABSTRACT A wet scrubber having spray means for spraying a liquid into a passageway, and a rod scrubber positioned downstream of the spray means by which impurities can be removed from the gas stream. The rods of the scrubber are rotatably mounted, so that they can be rotated to a position parallel to the gas flow when it is desired. The rods are removab1y attached, so that they can be readily replaced if the need arises.

4 Claims, 3 Drawing Figures 34 tunl auuguuuunm PATENTEBIAY H915 3,730,499

SHEET 1 BF 2 INVENTOR. J14 ME 5 IONA KIN PAIENTEB 1 SHEET 2' [IF 2 FIG 3 rllllnlllllull INVENTOR. JAME9 IONA KIN WJ 0 0/ 4rra2A/EY DAMPER-ROD SCRUBBER BACKGROUND OF THE INVENTION The invention relates to a wet scrubber for removing impurities from dirty gases. Many industries, especially where combustion processes are carried out, have been compelled in recent times to install means for removing impurities from gases that are being exhausted to the atmosphere. One such means used is a rod scrubber consisting of a plurality of bars or rods which extend transversely across the width of a gas passage. A spray is located upstream of the rods, and the water as it passes through the openings between the rods collects the gaseous impurities.

In some combustion installations, for example furnaces of steam generating units, the provision for buming alternative fuels is made. Thus, for example, a dirty fuel such as coal which contains ash and sulfur may be burned during certain times, and a clean fuel such as natural gas is used at other times. When coal is burned, the exhaust gases have to be cleaned. The exhaust from the combustion of natural gas does not have to be cleaned. Thus it is desirable to remove the rod scrubber from the exhaust gas passageway when burning natural gas, so that fan power requirements can be reduced. Also as the steam generating load varies, the volume of exhaust varies, and thus the pressure drop across the scrubber varies. Since the cleaning efficiency of the scrubber is dependent on the differential pressure across thescrubber, it is desirable to be able to add or remove scrubber rods as the load on the steam generator moves up or down.

SUMMARY OF THE INVENTION The wet scrubber of my invention utilizes a plurality of scrubber rod beds, any one or all of which can be rotated 90 to a position where the rods are parallel to the flow of gases, thereby effectively removing them from the gas stream. In addition, the rods are removably secured so that the width of the slits between the rods can be varied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional side view of a wet scrubber constructed in accordance with the invention;

FIG. 2 is a sectional view taken on lines 22 of FIG. 1; and I FIG. 3 is a view similar to FIG. 2, after the scrubber rods have been rotated 90.

DESCRIPTION OF THE PREFERRED EMBODIMENT Looking now to FIG. 1 of the drawings, designates a wet scrubber constructed in accordance with the invention. Dirty gases to be cleaned flow through duct 12 from a source, for example the furnace of a steam generator. These dirty gases are first subjected to a water spray from sprinkler 16, located in the upper portion of vertical duct 14. The gases together with the water then pass through a rod scrubber 18, where a large percentage of the impurities are removed with the water.

The gases then flow through a second water spray from sprinkler 20, and through a second bed of scrubber rods 22, where the gases are again washed.

The separated water droplets capture the solid particles and absorb certain gases, and fall by gravity to the floor of the scrubber housing, and are removed by pump 24. The gases leaving rod scrubber 22 reverse their direction and flow upwardly through passage 26 to the outlet 30, where they are discharged to the atmosphere. Positioned within passage 26 is a demister 28, which can be in the form of a plurality of zig-zag baffle plates. The continuous changing of direction of the gases flowing through the demister 28 causes separation of most of the fine water droplets still remaining in the gas stream. This water runs down the surfaces of the baffle plates, and drops to the scrubber housing floor, to be removed by pump 24.

As seen in FIGS. 2 and 3, the rods 22 are mounted on a rotatable axle 35. By means of motor 34, the rods 22 can be rotated 90 (FIG. 3), so mat the rods are parallel to the walls of duct 14. This effectively removes the rods from the gas passage as far as cleaning is concerned, and also with respect to their forming a restriction in the flow path. Motor 32 (FIG. 1) is used to rotate the rods of scrubber 18 to a vertical or horizontal position. Thus the rods of both rod scrubbers l8 and 22 can be rotated so that they are parallel to the walls of the gas passage. This would be done when a clean fuel, for example natural gas, was being burned in the furnace.

Alternatively, either one or both of the rod scrubber beds could be placed in their operating positions so that the rods extend transversely of the gas passage. As mentioned previously, the cleaning efficiency is dependent on the pressure drop across the scrubber rod beds, which pressure drop is determined by the volume of gases passing therethrough. For example, when a steam generator is operating at full load, there may be 1 million cubic feet per minute of gases passing through the wet scrubber 10. With just rod scrubber 18 in operation, the pressure differential across the rod scrubber may be 8 inch water gauge. When the steam generator is operating at half load, there may only be 500,000 ft. /min. of gases, and the pressure differential across rod scrubber 18 may only be 2 or 3 inch water gauge. By placing the rod scrubber 22 in operation, the pressure differential across both

rod scrubbers

18 and 22 may again approximate 8 inch water gauge. If, the greatest cleaning efficiency for the amount of impurities in the gases were determined to be 8 inch pressure differential, then both rod scrubbers would be placed in operation when the unit was operating at half load.

Another feature of the invention is the simplicity with which the size of the scrubber rods can be changed, thereby changing the width of the slits between the rods. As seen in FIGS. 2 and 3, the rods are made up of inner rod members 36, which are integral with the axle 35. Slipped over the inner rod members 36 are outer sleeve members 38. Sleeve memscrubber bed arrangements, depending on whether both beds are in operating position, or just bed 18 or bed 22 alone. The rods or rod scrubber 18 are made up of inner rods and outer removable sleeves, as is the case of rod scrubber 22.

What is claimed is:

1. In a wet scrubber for removing impurities from gases, passage means through which the gases flow, spray means for spraying a liquid into the passage means, a plurality of parallel, spaced, rod means extending transversely across the passage means downstream of the spray means, and means for rotating the rod means 90, so that the rod means are parallel to the axis of the passage means.

2. The wet scrubber set forth in claim 1, wherein each of rod means is made up of an inner rod, and an outer sleeve surrounding inner rod, and means for removably securing the outer sleeve to the inner rod, so that the outer sleeve can be replaced when desired.

3. In a wet scrubber for removing impurities from gases, passage means through which the gases flow,

passage means downstream of the first rod means, thereby forming a plurality of slits between the second rod means through which the gases may flow, and means for rotating the second rod means so that the second rod means are parallel to the axis of the passage means.

4. The wet scrubber set forth in claim 3, wherein the first rod means are of a different size than the second rod means, so that the slits between the first rod means have a different width than that of the slits between the second rod means.

Claims

1. In a wet scrubber for removing impurities from gases, passage means through which the gases flow, spray means for spraying a liquid into the passage means, a plurality of parallel, spaced, rod means extending transversely across the passage means doWnstream of the spray means, and means for rotating the rod means 90*, so that the rod means are parallel to the axis of the passage means.

3. In a wet scrubber for removing impurities from gases, passage means through which the gases flow, spray means for spraying a liquid into the passage means, a plurality of first parallel, spaced, rod means extending transversely across the passage means downstream of the spray means, thereby forming a plurality of slits between the first rod means through which the gases may flow, means for rotating the first rod means 90*, so that the first rod means are parallel to the axis of the passage means, a plurality of second parallel, spaced, rod means extending transversely across the passage means downstream of the first rod means, thereby forming a plurality of slits between the second rod means through which the gases may flow, and means for rotating the second rod means 90*, so that the second rod means are parallel to the axis of the passage means.