Patent Publication Number: US-9415338-B2

Title: Process equipment contaminant removal

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application that claims the benefit of U.S. application Ser. No. 13/650,609 filed on Oct. 12, 2012, now U.S. Pat. No. 8,613,895 which is a non-provisional application that claims the benefit of U.S. application Ser. No. 61/546,105 filed on Oct. 12, 2011, which U.S. application Ser. Nos. 13/650,609 and 61/546,105 are incorporated by reference herein in their entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the field of chemical and industrial facilities and more specifically to removing water from a vapor using a vacuum box. 
     2. Background of the Invention 
     There is an increased need for improving efficiency and reducing environmental concerns in the cleaning of industrial equipment such as process towers and the like. For instance, equipment holding hydrocarbons or other contaminants is cleaned for a variety of reasons such as for maintenance or a plant turnaround. Such maintenance and plant turnarounds typically involve accessing the equipment. Before the equipment may be accessed, the hydrocarbons and other contaminants are often removed from the equipment. A variety of conventional processes have been used to remove the hydrocarbons and other contaminants from the equipment. Such conventional processes include using steam to remove the hydrocarbons and other contaminants. Drawbacks to such conventional processes include disposal of the removed hydrocarbons and other contaminants. For instance, the steam exiting the equipment (e.g., process tower) may contain hydrocarbons and other contaminants. 
     Methods have been developed to dispose of such removed hydrocarbons and other contaminants. Such developments include processing the steam to remove the hydrocarbons and other contaminants. For instance, such developments include flaring the steam. Drawbacks to flaring the steam include environmental issues such as organic levels of the flare. 
     Consequently, there is a need for an improved method and system for cleaning process equipment. Further needs include improved methods and systems for removing contaminants such as hydrocarbons from a vapor (e.g., steam). Additional needs include improved equipment for removing hydrocarbons and other contaminants from a vapor such as steam. 
     BRIEF SUMMARY OF SOME OF THE PREFERRED EMBODIMENTS 
     These and other needs in the art are addressed in one embodiment by a contaminant removal system having a vacuum box. A contaminated vapor from process equipment is introduced to the vacuum box. The contaminated vapor includes steam and hydrocarbons. The vacuum box includes a water removal device. The water removal device removes water from the contaminated vapor to provide water and a reduced water vapor. The contaminated vapor is introduced to the vacuum box below the water removal device. The water and the reduced water vapor are removed from the vacuum box. In addition, the water removal device is disposed in the vacuum box at an elevation below an elevation at which the reduced water vapor is removed from the vacuum box. 
     These and other needs in the art are addressed in another embodiment by a method for removing contaminants from process equipment. The method includes introducing steam to the process equipment to provide a contaminated vapor. The method also includes introducing the contaminated vapor to a vacuum box. The contaminated vapor includes steam and hydrocarbons. The method further includes removing water from the contaminated vapor. The vacuum box includes a water removal device. The water removal device removes water from the contaminated vapor to provide water and a reduced water vapor. In addition, the method includes removing the water and the reduced water vapor from the vacuum box. The reduced water vapor is removed from the vacuum box at an elevation above an elevation at which the water removal device is disposed in the vacuum box. 
     The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other embodiments for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent embodiments do not depart from the spirit and scope of the invention as set forth in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a detailed description of the preferred embodiments of the invention, reference will now be made to the accompanying drawings in which: 
         FIG. 1  illustrates an embodiment of a contaminant removal system having a vacuum box; 
         FIG. 2  illustrates an embodiment of a contaminant removal system having two vacuum boxes in a parallel configuration; 
         FIG. 3  illustrates an embodiment of a contaminant removal system having two vacuum boxes in a series configuration; 
         FIG. 4  illustrates an embodiment of a contaminant removal system having vacuum boxes disposed in series and parallel configurations; 
         FIG. 5  illustrates an embodiment of a contaminant removal system having a vacuum box and a distributor; and 
         FIG. 6  illustrates an embodiment of a vacuum box in which the water removal device includes weirs. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  illustrates an embodiment of contaminant removal system  5  having process equipment  10  and vacuum box  15 . Embodiments include using steam to remove contaminants from process equipment  10 . Water  40  is removed from the vapor (e.g., contaminated vapor  30 ) exiting process equipment  10  by vacuum box  15 . By vacuum box  15  removing water  40  from contaminated vapor  30 , the vapor (e.g., reduced water vapor  35 ) is available for further processing such as by a thermal destruction device  20 . 
     In embodiments as shown in  FIG. 1 , vacuum box  15  includes any vessel suitable for allowing a vacuum to be pulled on a vapor and in which water is to be removed from the vapor. In embodiments, contaminated vapor  30  exits process equipment  10  and is introduced to vacuum box  15 . A vacuum is created in vacuum box  15  as contaminated vapor  30  flows through and exits vacuum box  15 . In embodiments, vacuum box  15  includes water removal device  45 , which removes water  40  from the contaminated vapor  30  as it flows through vacuum box  15 . Water removal device  45  includes any device suitable for removing water from a vapor. In an embodiment, water removal device  45  is a demister pad. Any demister pad configuration suitable for removing the water may be used. In embodiments, the demister pad includes orifices through which the vapor passes, with the removed water collected in bottom portion  75  of vacuum box  15 . In an embodiment, the demister pad extends about horizontally across vacuum box  15 . The demister pad may be attached to vacuum box  15  by any suitable means. In an embodiment, clips are secured to vacuum box  15 , and the demister pad is attached to the clips. The clips may be secured to vacuum box  15  by any suitable means such as by welds, adhesives, bolts, and the like. In an embodiment, the clips are welded to vacuum box  15 . The demister pad is attached to the clips by any suitable means such as by welds, adhesives, bolts, and the like. In an embodiment, the demister pad is attached to the clips by bolts. It is to be understood that vacuum box  15  is not limited to a configuration with the demister pad extending horizontally but in alternative embodiments may include other configurations of disposing the demister pad in vacuum box  15 . In some embodiments, suitable vessels existing at the industrial facility are modified (i.e., on-site) to produce vacuum box  15 . 
     As shown in the embodiments of  FIG. 1  in which water removal device  45  is a demister pad, contaminated vapor  30  is introduced to vacuum box  15  below water removal device  45  and above the water level in vacuum box  15 . In alternative embodiments, contaminated vapor  30  is introduced to vacuum box  15  about at the water level in vacuum box  15 . In embodiments, water removal device  45  is disposed at an elevation in vacuum box  15  that is below the elevation at which reduced water vapor  35  exits vacuum box  15 . In embodiments, contaminant removal system  5  has a back flow valve  65  on the feed of contaminated vapor  30  to vacuum box  15 . Back flow valve  65  prevents the back flow of water from vacuum box  15  into the feed line of contaminated vapor  30  to vacuum box  15 . Back flow valve  65  may be any valve suitable for preventing the flow of water back into the feed of contaminated vapor  30  to vacuum box  15 . In embodiments, back flow valve  65  is a one-way valve. In embodiments, back flow valve  65  is a check valve. In an embodiment, vacuum box  15  has water level measurement device  70 . Water level measurement device  70  may be any device suitable for measuring the level of water in vacuum box  15 . Without limitation, examples of water level measurement devices  70  are a level sensor, a floating water level measuring device, a sight level, or any combinations thereof. In embodiments, water level measurement device  70  is a floating water level measuring device. 
     In embodiments of operation of vacuum box  15  as shown in  FIG. 1 , contaminated vapor  30  is introduced to bottom portion  75  of vacuum box  15  and flows from bottom portion  75  through water removal device  45  (i.e., through the orifices in demister pad) and into upper portion  80  of vacuum box  15 . A portion or all of the water in contaminated vapor  30  is separated from the vapor and remains in bottom portion  75  with reduced water vapor  35  exiting vacuum box  15 . Water level measuring device  70  measures the level of water in bottom portion  75 . When the level is about at a target water level, water  40  is drained from vacuum box  15 . In some embodiments, water level measuring device  70  and the draining of water  40  from vacuum box  15  are automated. Such automation may be by any suitable methods. Water  40  may be drained by any suitable means. In embodiments, bottom  105  of vacuum box  5  has one or more drains valves (not illustrated). In some embodiments, side  85  and/or side  110  may have one or more drain valves (not illustrated). The target water level may be any desired level. In embodiments, the target water level is about at or below the elevation at which contaminated vapor  30  is introduced to vacuum box  15 . In some embodiments, the target level is about at or below the elevation at which contaminated vapor  30  is introduced to vacuum box  15  and between about 50 percent and about 85 percent of the height of bottom portion  75 , alternatively about at or below the elevation at which contaminated vapor  30  is introduced to vacuum box  15  and between about 70 percent and about 80 percent of the height of bottom portion  75 . The target level may also be any height or ranges of heights included within the above ranges. 
     As further shown in  FIG. 1 , embodiments of contaminant removal system  5  include reduced water vapor  35  being removed from side  85  of vacuum box  15 . In embodiments, side  85  is on the opposing side of vacuum box  15  from side  110  at which contaminated vapor  30  is introduced to vacuum box  15 . Without limitation, such location of the exit of reduced water vapor  35  may reduce or prevent crimp in a hose in embodiments in which reduced water vapor  35  exits vacuum box  15  via a hose. Further, without limitation, such location of the exit of reduced water vapor  35  may reduce or prevent water splash. 
     In some embodiments of contaminant removal system  5 , contaminated vapor  30  is introduced into vacuum box  15  at entry angle  90 . Entry angle  90  may be any desired angle. In embodiments, entry angle  90  is from about 30 degrees to about 90 degrees, alternatively from about 45 degrees to about 90 degrees, and alternatively from about 30 degrees to about 60 degrees, and further alternatively from about 45 degrees to about 65 degrees, and alternatively about 45 degrees. In embodiments, entry angle  90  is any angle or range of angles within the range of angles above. 
     In embodiments as shown in  FIG. 6 , water removal device  45  includes weirs  95 . Weirs  95  may be disposed at any suitable location for removing water from contaminated vapor  30 . In some embodiments as shown, weirs  95  are perpendicular to top  100  and bottom  105  of vacuum box  15 . In embodiments, weirs  95  are solid. 
     In embodiments, contaminant removal system  5  includes sampling water  40  before removal from vacuum box  15 . The sampling may be accomplished by any suitable means. In embodiments, contaminant removal system  5  may include a sample port disposed on one or more drains. In some embodiments, a sample port may be disposed on the line (i.e., hose) by which water  40  is drained from vacuum box  15 . In an embodiment, water  40  is tested for chemical oxygen demand (e.g., COD). In embodiments, water  40  is drained to a container (not illustrated) and tested. 
     In further embodiments of contaminant removal system  5  as shown in  FIG. 1 , contaminant removal system  5  includes blowers  115 . Blowers  115  may be any suitable device for increasing pressure on contaminated vapor  30  and/or reduced water vapor  35 . In embodiments, blowers  115  are compressors. In embodiments, one or more blowers  115  may operate on contaminated vapor  30 , and/or one or more blowers  115  may operate on reduced water vapor  35 . Without limitation, blowers  115  have sufficient strength to maintain movement of the vapors (i.e., contaminated vapor  30  and reduced water vapor  35 ). Further, without limitation, maintaining such movement prevents or reduces condensation in a line. 
     In an embodiment of operation of contaminant removal system  5  as shown in  FIG. 1 , steam  25  is fed to process equipment  10 . Steam  25  may be fed to process equipment  10  under any suitable conditions to remove hydrocarbons and other contaminants from process equipment  10 . A commercial example of a suitable steam process is VAPOUR-PHASE®, which is a registered trademark of United Laboratories International, LLC. Steam  25  enters process equipment  10  and removes a portion or all of the hydrocarbons and other contaminants in process equipment  10 . In embodiments, steam and an oxidizer enter process equipment  10  and remove a portion or all of the hydrocarbons and other contaminants in process equipment  10 . Steam  25  with the hydrocarbons and other contaminants exits process equipment  10  as contaminated vapor  30 . Contaminated vapor  30  is introduced to vacuum box  15 . Contaminated vapor  30  flows through vacuum box  15  creating a vacuum in vacuum box  15 . In embodiments, as contaminated vapor  30  passes through vacuum box  15  in a vacuum, water removal device  45  (e.g., demister pad) facilitates removal of a portion or all of the water in contaminated vapor  30 . The water collects at bottom portion  75 . In some embodiments (not illustrated), a pump or pumps may facilitate removal of water  40  from vacuum box  15 . The pumps may be any suitable type of pump such as, without limitation, diaphragm pumps. Reduced water vapor  35  exits vacuum box  15  and may be further processed. In some embodiments, a portion or all of the hydrocarbons and other contaminants exit vacuum box  15  with reduced water vapor  35 . Without limitation, the hydrocarbons and other contaminants leave with the gas because of the high temperatures involved. In an embodiment as shown, reduced water vapor  35  is fed to thermal destruction device  20 . 
     Thermal destruction device  20  may be any device suitable for thermally destroying reduced water vapor  35 . Without limitation, examples of thermal destruction devices  20  include thermal oxidizers, incinerators, and the like. Any thermal oxidizer may be used that is suitable for incinerating reduced water vapor  35 . Without limitation, examples of thermal oxidizers include electric thermal oxidizers, gas fueled thermal oxidizers, and catalytic thermal oxidizers. 
       FIG. 2  illustrates an embodiment of contaminant removal system  5  having a parallel vacuum box  15  configuration. In such an embodiment, contaminant removal system  5  includes two vacuum boxes  15 ,  15 ′ with contaminated vapor  30  being introduced to both. Vacuum boxes  15 ,  15 ′ may be the same size and configuration or different sizes and configurations. In an embodiment, vacuum boxes  15 ,  15 ′ are of the same size and configuration. Waters  40 ,  40 ′ are removed from contaminated vapor  30  by vacuum boxes  15 ,  15 ′, and reduced water vapors  35 ,  35 ′ exit vacuum boxes  15 ,  15 ′. Water removal devices  45 ,  45 ′ facilitate removal of waters  40 ,  40 ′. In embodiments as shown, reduced water vapor  35  is fed to thermal destruction device  20 , and reduced water vapor  35 ′ is fed to thermal destruction device  20 ′. In other embodiments (not illustrated), reduced water vapors  35 ,  35 ′ may be fed to the same thermal destruction device. In an embodiment, vacuum boxes  15 ,  15 ′ are disposed on the same transportation means (e.g., both disposed on the same trailer). In other embodiments, vacuum boxes  15 ,  15 ′ are disposed on different transportation means. 
       FIG. 3  illustrates an embodiment of contaminant removal system  5  having a series vacuum box  15  configuration. In such an embodiment, contaminant removal system  5  includes two vacuum boxes  15 ,  15 ′ in the series configuration. Vacuum boxes  15 ,  15 ′ may be the same size and configuration or different sizes and configurations. In an embodiment, vacuum boxes  15 ,  15 ′ are of the same size and configuration. In some embodiments, each successive vacuum box is smaller than the previous vacuum box. In the embodiment as shown, contaminated vapor  30  is introduced to vacuum box  15  in which water removal device  45  (e.g., demister pad) facilitates removal of water  40  from contaminated vapor  30 . Reduced water vapor  35  is then introduced to vacuum box  15 ′ in which water removal device  45 ′ facilitates removal of water  40 ′ from reduced water vapor  35 . Reduced water vapor  35  flowing through vacuum box  15 ′ facilitates a vacuum in vacuum box  15 ′. Further reduced water vapor  50  exits vacuum box  15 ′. In embodiments as shown, further reduced water vapor  50  is fed to thermal destruction device  20 . In an embodiment, vacuum boxes  15 ,  15 ′ are disposed on the same transportation means (e.g., both disposed on the same trailer). In other embodiments, vacuum boxes  15 ,  15 ′ are disposed on different transportation means. 
       FIG. 4  illustrates an embodiment of contaminant removal system  5  having a parallel and series vacuum box  15  configuration. In such an embodiment, contaminant removal system  5  includes vacuum boxes  15 ,  15 ′ in the series configuration with each other and vacuum boxes  15 ″,  15 ′″ in the series configuration with each other. Vacuum boxes  15 ,  15 ′ are in the parallel configuration to vacuum boxes  15 ″,  15 ′″. Vacuum boxes  15 ,  15 ′,  15 ″,  15 ′″ may be the same size and configuration or different sizes and configurations. In an embodiment, vacuum boxes  15 ,  15 ″ are of the same size and configuration, and vacuum boxes  15 ′ and  15 ′″ (e.g., the successive vacuum boxes) are of a smaller size. In the embodiment as shown, contaminated vapor  30  is introduced to vacuum boxes  15 ,  15 ″ in which water removal devices  45 ,  45 ″ (e.g., demister pads) facilitate removal of waters  40 ,  40 ″ from contaminated vapor  30 . Reduced water vapors  35 ,  35 ′ are then introduced to the successive (e.g., downstream) vacuum boxes  15 ′,  15 ′″ in which water removal devices  45 ′,  45 ′″ facilitate removal of waters  40 ′,  40 ′″ from reduced water vapors  35 ,  35 ′. Further reduced water vapors  50 ,  50 ′ exit vacuum boxes  15 ′,  15 ′″. In embodiments as shown, further reduced water vapors  50 ,  50 ′ are introduced to thermal destruction devices  20 ,  20 ′. In alternative embodiments (not shown), further reduced water vapors  50 ,  50 ′ are introduced to the same thermal destruction device  20 . Vacuum boxes  15 ,  15 ′,  15 ″, and  15 ′″ may all be disposed on the same transportation means (e.g., all disposed on the same trailer) or on two or more transportation means. In embodiments, vacuum boxes  15 ,  15 ′,  15 ″,  15 ′″ are all disposed on the same transportation means. In other embodiments, vacuum boxes  15 ,  15 ′ are both disposed on the same transportation means, and vacuum boxes  15 ″,  15 ′″ are both disposed on another transportation means. 
       FIG. 5  illustrates an embodiment of contaminant removal system  5  in which reduced water vapor  35  is fed to distributor  55 . Distributor  55  may include any means suitable for separating reduced water vapor  35  into different vapor streams  60 . In an embodiment, distributor  55  is a manifold. Distributor  55  may separate water vapor  35  into any desired number of vapor streams  60 . In embodiments (not illustrated), each vapor stream  60  may be sent to a different downstream purpose such as, without limitation, one or more different thermal destruction devices  20 . In some embodiments (not illustrated), contaminated vapor  30  may be introduced to distributor  55  prior to being fed to one or more than one vacuum box  15 . 
     In an embodiment, vacuum box  15  is transportable. Vacuum box  15  may be transportable by any suitable means. Without limitation, examples of such means include by disposing vacuum box  15  on the bed of a vehicle (e.g., truck), on a trailer (e.g., attachable to a truck), or a freight wagon (e.g., a freight wagon attachable to a train locomotive). In an embodiment, vacuum box  15  is disposed on the bed of a trailer. Without limitation, a transportable vacuum box  15  allows vacuum box  15  to be used with different process equipment  10  in the facility. In addition, a transportable vacuum box  15  allows vacuum box  15  to be disposed in a desired close proximity to process equipment  10 . 
     In some embodiments, process equipment  10  includes any equipment used in an industrial facility such as a refinery or chemical plant. In an embodiment, process equipment  10  includes any equipment that may have hydrocarbons. In embodiments, process equipment  10  includes a process tower, tanks, vessels, heat exchangers, and the like. 
     It is to be understood that embodiments of contaminant removal system  5  are not limited to the number of vacuum boxes shown in the figures. In alternative embodiments, contaminant removal system  5  may include any desired number of vacuum boxes in parallel and/or in series configurations. 
     Contaminated vapor  30 , reduced water vapor  35 , further reduced water vapor  50 , and vapor stream  60  may flow between equipment (i.e., from process equipment  10  to vacuum box  15 ) by any suitable means. In an embodiment, such suitable means includes through hoses. In embodiments, the hoses are hoses that may operate with a vacuum. In some embodiments, the hoses are stainless steel braided hoses. In other embodiments, one or more of the hoses has one or more valves. In embodiments, each hose has a valve. In some embodiments, contaminant removal system  5  includes hard-piping instead of hoses. 
     Embodiments include using contaminant removal system  5  after process equipment  10  has been removed of heavy hydrocarbons (e.g., de-oiled), and remaining hydrocarbons and other contaminants are to be removed from process equipment  10 . The hydrocarbons and other contaminants may be removed from process equipment  10  for any desired reason such as for a plant turnaround, maintenance, manual access to the process equipment, and the like. 
     Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the invention as defined by the appended claims.