US3691732A - Baffle construction for flare seal drums - Google Patents

Abstract

A baffle construction and arrangement for a flare seal drum to prevent makeup or seal water supplied to the drum from continuously flushing water saturated with undesirable dissolved materials, such as hydrogen sulfide (H2S), to the sewer while preventing hydrocarbon buildup within the flare seal drum.

Description

United States Patent Richards et al.

[ 51 Sept. 19, 1972 [54] BAFFLE CONSTRUCTION FOR FLARE SEAL impMs Inventors: John F. Richards Baton Rouge:

La. 70806; Walter L. Terrell, Jr., elflaakaifififi- Assignee: Esso Research and Engineering r e e e Filed: June 18, 1970 Appl. No.: 47,527

US. Cl. ..55/227, 55/244, 55/256, 261/8 Int. Cl. ..B0ld 47/02 Field of Search ..55/255, 256, 355, 227, 244, 55/421, 73, 245-254, 355; 261/8 References Cited UNITED STATES PATENTS 835,243 il /1906 Jetifreysw. 15M421:

2,180,849 11/1939 Printz ..55/228 2,484,277 10/1949 Fisher ..55/228 2,850,877 9/1958 Slomer ..55/256 3,387,432 6/1968 Ferrara ..55/228 3,451,198 6/1969 Axelsson ..55/485 2,164,833 7/1939 Norman ..55/227 Primary Examiner-Bernard Nozick Attorney-Manahan and Wohlers and F. Donald Paris [5 7] ABSTRACT A baffle construction and arrangement for a flare seal drum to prevent makeup or seal water supplied to the drum from continuously flushing water saturated with undesirable dissolved materials, such as hydrogen sulfide (H S), to the sewer while preventing hydrocarbon buildup within the flare seal drum.

6 Claims, 1 Drawing Figure 49 ama/4s BAFFLE CONSTRUCTION FOR FLARE SEAL DRUMS BACKGROUND OF THE INVENTION A conventional design for a flare seal drum generally provides for a makeup water rate of approximately 40 gallons/minute (GPM) to insure prompt reestablishment of the water seal after a blow has occurred. When a stream being flared contains hydrogen sulfide (H 8), the seal water becomes saturated and carries the hydrogen sulfide (H 8) out with it into the sewer. The sewer normally is hot so that the poisonous hydrogen sulfide (H 8) is released thereby creating a dangerous situation. One possibility is that the water could be injected directly into the dip leg to avoid flushing hydrogen sulfide (H 8) into the sewer, but this arrangement would permit an undesirable buildup of condensed hydrocarbons in the seal drum. Other prior art seal drum constructions utilize a single baffle, which functions as an overflow weir, wherein the makeup water is supplied directly into the main portion of the seal drum thereby causing the hydrogen sulfide-saturated water to overflow and subsequently be carried out of the seal drum into the sewer. As previously mentioned, this type of arrangement is undesirable because of the fact that poisonous hydrogen sulfide (H 8) will be released in the hot sewer to create a relatively dangerous situation.

For background purposes, the present invention is employed in an apparatus and process for flaring combustible gaseous materials and especially for the flaring and burning of gaseous hydrocarbon material where such materials are derived from operations for the refining of petroleum oils in various industrial operations and more particularly, in the refining of petroleum oils, large volumes of combustible gaseous materials are produced. As is apparent, some of these materials have no real economic value as fuel or otherwise, and therefore must be disposed of in a suitable manner. Further, such materials result from upset conditions in the normal operation of a refinery wherein gases which ordinarily might be subjected to further processing in order to obtain valuable products therefrom must be vented in order to avoid the occurrence of dangerously abnormal pressures in operating equipment. The total volume of all such accumulations of gases in normal refinery operation and the hazardous nature thereof make it almost impossible for such gases to be discharged directly into the atmosphere. Thus, in practice it is customary to burn such gases as they are discharged from an exhaust or flare stack at a considerable distance above the ground although on occasion for the sake of economy, burning may be accomplished in relatively low large diameter enclosures or flare structures. The flare seal drum fits into the overall flaring apparatus and process in that it prevents flashback, that is, it prevents a backfeed of the flame. By preventing any backfeed of air the possibility of combustion is substantially eliminated and thus, an explosive situation is avoided. As mentioned heretofore, the prior art has suggested various flare seal drum constructions and arrangements for preventing the dispersement of hydrogen sulfide-saturated water from being carried out into the sewer, but for the most part the prior art has been unsuccessful in solving this problem.

SUMMARY OF THE INVENTION The present invention overcomes the deficiencies of the prior art and is designed to prevent the makeup water or liquid seal supply from continuously flushing water saturated with hydrogen sulfide (H s) to the sewer while preventing a hydrocarbon buildup in the flare seal drum.

The flare seal drum construction and arrangement for overcoming the deficiencies of the prior art comprises a series of baffles installed at one end, for example the overflow end of the seal drum such that baffles prevent essentially all mixing of the makeup waterwith the hydrogen sulfide-saturated water already in the seal drum and thus, any overflow will contain very little hydrogen sulfide (H 8). At the same time the baffles permit the water to displace any condensed hydrocarbons because of the difference in gravity so that the water will overflow to the sewer and no buildup will occur. Toward this end the seal drum is provided at its overflow end with preferably three longitudinally spaced baffles, two of which are of the same height with the second or intermediate baffle being slightly lower in height than the other two baffles. In a flare seal drum constructed according to the teachings of the present invention, the inlet for the liquid seal supply or makeup water is located at the baffle end between the two baffles closest the overflow end to effectively segregate the water flow through the drum from the gases being flared. Also, there is provided a third baffle situated furthest from the overflow end of the drum for cooperating with the other baffles to prevent any mixing between the hydrogen sulfide-saturated water and the incoming makeup water. In effect, these baffles confine the hydrogen sulfide-saturated water within a predetermined area or main portion of the seal drum, or in other words, the hydrogen sulfide-saturated water is confined in a backpocket of the drum thereby preventing any overflow and subsequent drainage into the sewer. As the makeup water flows into the seal drum it is separated from the hydrogen sulfide-saturated water so that this new water supply cannot pick up any significant amount of the hydrogen sulfide-saturated water. Thus, any water overflow will be of water containing a minimum or permissible amount ofhydrogen sulfide (H 8) that will not create an undesirable situation to occur once the water passes into the sewer.

Accordingly, it is a primary object of the present invention to provide a novel and improved construction and arrangement for a flare seal drum for preventing incoming makeup water from continuously flushing water saturated with hydrogen sulfide (H 8) to the sewer while at the same time preventing any undesirable hydrocarbon buildup in the flare seal drum.

A further object of the present invention is to provide a novel and improved construction for a flare seal drum which employs a series of baffles to prevent the flushing of water saturated with hydrogen sulfide (H 8) from the drum.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the combinations and arrangements as illustrated in the presently preferred embodiment of the invention which thereinafter set forth in BRIEF DESCRIPTION OF THE DRAWING g The drawing illustrates schematically a flare seal drum constructed and arranged according to the teachings of the instant invention.

' DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing reference numeral designates an elongated flare seal drum having elliptical-shaped ends and a conduit inlet 11 for receiving disposable and combustible gases from a main conduit (not shown). The conduit 11 extends into the flare seal drum l0 and terminates below the surface or water level (W.L.) of a body of 'seal liquid designated 12 which is maintained therein substantially-at the level of the overflow weirs or baffles 13 and, which water level typically may be approximately 24 to 48. inches. As illustrated, a valved conduit line 15 provides an inlet for the makeup water or liquid seal for the drum 10. The inlet 15 is disposed to enter the drum 10 at its overflow end designated 24, between the overflow weir-or baffle 13 and a third baffle l6 spaced intermediate equidistant from the baffles Band 14. Further, the overflow weirs 13 and 14 terminate at the same height relative to the bottom of the drum 10, whereas the intermediate baffle 16 has a height slightly less, for example, two inches below the normalwater level (W.L.) of the seal liquid 12. For drainage of the overflow seal liquid from the drum 10, there is provided a conduit 17 connected adjacent the overflow end 24 of the drum 10. In the event that it is desirable or necessary to completely drain the flare seal drum 10 of the liquid 12 contained therein, provision is made therefore by providing a conventional valved drainage conduit connection 18 adjacent the opposite end of the drum 10. Further, an aperture or weep hole 19 may be provided in the intermediate baffle 16 adjacent the lower'end thereof to permit drainage of substantially all the water from the drum, particularly that in the vicinity of the baffles. The conduit connections 20, 21, which communicate with the upper portion of minate approximately four inches above the bottom of the flare seal drum and may extend to a height of 38 inches which will accommodate the maximum water level in the drum. The dimensions previously set forth I are intended to be illustrative only and are not intended to be limiting upon the present invention, since it is readily apparent that depending on the particular situation and facts involved, the dimensions may vary one way or the other and readily would be within the skill of those working in the art once the teachings of the present invention were known to them.

As illustrated, the lower portion of the vessel atthe overflow end contains the baffle construction and arrangement previously described. These baffles, which are made of carbon steel, may be circular in nature or of any other suitable shape that corresponds to the vention, there is a significant reduction in the amount the drum [0 above the level (W.L.) of seal liquid 12,

seam length (excluding the elliptical end) of about 30 feet. As mentioned hereinbefore, the water level may be about 24 inches with the gas inlet conduit 11 being disposed approximately 18 inches below the water level (W.L.)or 14 inches above the bottom of the drum 10. A typical arrangement of the internal baffle construction may be wherein the intermediate baffle 16 is spaced about one-half to one foot equidistantly from the baffles 13 and 14. The baffle l4 typically may terof material (e.g., l-I,S) dissolved in the water leaving the seal drum. This is particularly beneficial in meeting the requirements for safety and clean water that leaves the refinery. It is clear that by constructing a flare seal drum according to the teachings of the present invention .as disclosed heretofore, the water that flows through the drum is substantially'segregated from any of the gases that are, being flared- Also, by installing the baffle arrangement as illustrated and described, the amount of material dissolved in the water leaving the seal drum is greatly reduced. This reduction in the material dissolved in the water significantly reduces taste and odor. Further, the disclosed construction and arrangement is preferable to installing facilities that would permit reusing the seal water in the same seal since the purge from the reuse system would be much more highly concentrated in the taste and odor producing materials, and their overall reduction to the sewers would be less than for disclosed baffle construction and arrangement. Further, there is the possibility that a reuse system would create corrosion problems due to the concentrating corrosive materials. Thus, it is apparent that the present construction and arrangement will substantially reduce taste and odor problems that are present in the effluent, and further reduces the investment for any secondary treatment that may have been required heretofore to eliminate certain of the dissolved materials in the water.

Although the instant invention has been described with a certain degree of particularity, it is to be understood that the present disclosure has been made by way of an example and that obviously changes in the details of construction and arrangement of parts may be restored to without departing from the spirit and scope of the invention. Thus, the construction and arrangement of the flare seal drum described and illustrated for use with an elevated flare or vent, would be equally applicable where the vapors are disposed to a furnace burning pit, ground flare or the like. Accordingly, reference should be made to the following appended claims in determining the full scope of the in vention.

What is claimed herein is:

1. A flare seal drum containing a body of liquid seal having a predetermined upper surface level employed in a system for flaring combustible gaseous materials, said seal drum comprising an elongated vessel having a top and first and second ends, inlet conduit means for receiving combustible gaseous materials and extending through said top into said seal drum to a level substantially below said predetermined upper surface level to form a liquid contaminated with undesirable dissolved materials, outlet conduit means operably communicating with the upper portion of said seal drum above said predetermined upper surface level providing for release of gaseous material from said seal drum, a plurality of baffle means operably secured to said vessel and longitudinally spaced apart at said first end of said vessel for preventing any substantial mixing of the contaminated liquid with clean liquid seal supplied to the drum and substantially confining the contaminated liquid to a predetermined area in said drum to substantially reduce the amount of overflow and drainage of said contaminated liquid from said drum, said bafi'le means comprising first baffle means spaced from said first end and second baffle means spaced from said first baffle means on the side opposite said first end inlet means for supplying a steady flow of liquid seal to said vessel disposed between said first and second baffle means, and outlet means for removing the substantially uncontaminated overflow liquid from said vessel and located between said first baffle means and said first end.

2. A flare seal drum according to claim 1 wherein said plurality of baffle means includes a third baffle longitudinally-spaced from said second baffle on the side opposite said first end.

3. A flare seal drum according to claim 1 wherein said plurality of baffle means includes a third baffle longitudinally-spaced from said second baffle on the side opposite said first end, said baffles operably secured to said vessel and conforming in shape therewith, said first baffle being spaced from said one end of said vessel and extending upwardly from the bottom of said vessel for a first predetermined height, said second baffle being longitudinally-spaced from said first baffle on the side thereof opposite said first end of said vessel and extending upwardly from the bottom of said vessel for a second predetermined height which is less than said first predetermined height, said third baffle being longitudinally-spaced from said second baffle on the side opposite from said one end of said vessel and terminatsaid second baffle is longitudinally spaced equidistant from said first and third baffles.

6. A flare seal drum according to claim 5 wherein said second baffle includes an aperture at the end thereof adjacent the bottom of said vessel.

Claims (5)

1. 2. A flare seal drum according to claim 1 wherein said plurality of baffle means includes a third baffle longitudinally-spaced from said second baffle On the side opposite said first end.
2. 3. A flare seal drum according to claim 1 wherein said plurality of baffle means includes a third baffle longitudinally-spaced from said second baffle on the side opposite said first end, said baffles operably secured to said vessel and conforming in shape therewith, said first baffle being spaced from said one end of said vessel and extending upwardly from the bottom of said vessel for a first predetermined height, said second baffle being longitudinally-spaced from said first baffle on the side thereof opposite said first end of said vessel and extending upwardly from the bottom of said vessel for a second predetermined height which is less than said first predetermined height, said third baffle being longitudinally-spaced from said second baffle on the side opposite from said one end of said vessel and terminating at one end at a level corresponding to said first predetermined height.
3. 4. A flare seal drum according to claim 3 wherein the other end of said third baffle is spaced a predetermined amount above the bottom of said vessel.
4. 5. A flare seal drum according to claim 4 wherein said second baffle is longitudinally spaced equidistant from said first and third baffles.
5. 6. A flare seal drum according to claim 5 wherein said second baffle includes an aperture at the end thereof adjacent the bottom of said vessel.

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