Patent Publication Number: US-2009230052-A1

Title: Hydrogen sulfide filter

Description:
RELATED APPLICATIONS 
     The present application claims the benefit of co-pending provisional application No. 60/984536, filed on Nov. 1, 2007 and co-pending provisional application No. 61/026274 filed on Feb. 5, 2008, both of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The disclosure relates generally to filters, and more particularly, to a filter having a filter material for capturing hydrogen sulfide (H 2 S). 
     2. Related Art 
     Filter systems are commonly used for a large number of purposes and applications. In some applications, the use of a filter system is necessary for removing undesired elements that may contaminate a reaction or reduce the performance of a device/product/machine/system. Such applications may include a fuel cell system, a filtration system for a particular fuel (e.g., petroleum gas, natural gas, etc.), a water filtration system, an air filtration system, etc. A filter system for a fluid may include a particulate filter and a chemical filter. The particulate filter serves to remove dust, particles, granules, gravel, debris, etc., while the chemical filter serves to remove specific chemicals, not desired in the fluid. Examples of such undesirable chemicals or contaminants include hydrocarbons, oxides of sulfur, oxides of nitrogen, oxides of carbon and hydrogen sulfide, etc. 
     Filters for removing particulates may use membranes or layers of granular materials. As to filters for chemical contaminants, some commonly used filtration and/or purification techniques include: ion-exchange, distillation, osmosis, reverse osmosis, chemical adsorption, precipitation, coagulation, oxidation, flocculation, etc. 
     Chemical contaminants may be toxic and the removal of such contaminants requires careful handling in view of environmental concerns and governmental restrictions as to the release/disposal of such contaminants. Industrial retrieval of hydrocarbon fuels requires the filtration of contaminants like hydrogen sulfide, which is toxic and hazardous when released into the environment. For example, hydrogen sulfide is usually converted into molten sulfur or other stable compounds before disposal. 
     SUMMARY 
     A filter and filter system for the removal and/or disposal of particulates and/or chemical(s), including hydrogen sulfide (H 2 S), is disclosed. An embodiment of the filter system includes a filter material between two filter media, each filter media providing coalescing of liquid and particulate for removal thereof. The filter material includes an absorbent material having a surface configuration that exposes the absorbent material to a fluid passing there through. The absorbent material may include various chemical components and take the form of an absorbent fill, a single or multi-layered composite pack, and/or the like. The filter system may include a casing for housing the filter material and filter media. 
     A first aspect of the disclosure provides a filter material comprising: an absorbent material including: quartz, magnesium oxide, sodium sesquicarbonate dihydrate, aluminum oxide, sodium oxide, silicon oxide, and carbon. 
     A second aspect of the disclosure provides a filter system comprising: a first and a second filter media for removing particulates from a fluid passing there through; and a filter material disposed between the first and second filter media, wherein the filter material includes an absorbent material configured to capture hydrogen sulfide. 
     A third aspect of the disclosure provides a method for filtering a fluid, the method comprising: passing the fluid through a first filter media for removing particulates; passing the fluid through an absorbent material for removing hydrogen sulfide; and passing the fluid through a second filter media for removing particulates. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features of this disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure taken in conjunction with the accompanying drawings that depict various embodiments of the disclosure, in which: 
         FIG. 1  is a perspective view of an embodiment of a filter system according to the disclosure. 
         FIG. 2  is a top view of a section of the filter system illustrated in  FIG. 1 . 
         FIG. 3  is a perspective view of an embodiment of the filter material illustrated in  FIG. 1  and  FIG. 2 . 
         FIG. 4  is a perspective view of another embodiment of the filter material illustrated in  FIG. 1  and  FIG. 2 . 
         FIG. 5  is a side view of a screw-type fastener for an end cap illustrated in  FIG. 1 . 
     
    
    
     It is noted that the drawings of the disclosure are not to scale. The drawings are intended to depict only typical aspects of the disclosure, and therefore should not be considered as limiting the scope of the disclosure. In the drawings, like numbering represents like elements between the drawings. 
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an embodiment of a filter system  100  for filtering particulates and one or more chemicals, including hydrogen sulfide (H 2 S), from a fluid (e.g., a gas or liquid) according to the disclosure. In particular, filter system  100  can be used to filter a gas (e.g., natural gas, air, or the like), and can remove liquid and/or particulates in the gas, as well as hydrogen sulfide. Filter system  100  includes an outer core casing wall  102  and an inner core casing wall  104  coupled together by end caps  106  to form a concentric casing  116 . Filter system  100  is shown with one end cap  106  removed for viewing. Inner core casing wall  104  and outer core casing wall  102  may include, for example, carbon steel, stainless steel or other rigid material capable of withstanding exposure to a noxious gas. Inner core casing wall  104  and outer core casing wall  102  may include perforations  108  that allow the fluid to pass there through. End caps  106  may include, for example, molded urethane or metal. As shown in  FIG. 5 , an end cap  106  may include a screw-type fastener  140  such as that disclosed in U.S. Pat. No. 7,294,160, which is incorporated herein by reference. In this case, the end cap  106  may be secured to concentric casing  116  ( FIG. 1 ) with screw-type fastener  140  having a shaft  142  that is threaded  144  ( FIG. 5 ). 
     Returning to  FIG. 1 , within concentric casing  116 , a first filter media  110  adjacent to inner core casing wall  104  is provided for filtering a fluid by, for example, coalescing particulates to facilitate the removal thereof. A second filter media  112  adjacent to outer core casing wall  102  is arranged in a similar manner as first filter media  110  with respect to inner core casing wall  104  and also provides filtering (e.g., by coalescing particulates) and migration protection of the fluid. Migration protection is achieved by providing a barrier to prevent moisture from re-entering the filtered fluid. Each filter media  110 ,  112  may be pleated and/or wire bound for coalescing of particulate and debris. Filter media  110 ,  112  may include but is not limited to, for example, borosilicate micro fiberglass, which may be configured in multiple (e.g., five) layers encapsulated by a wire mesh  117  and/or a screen  115 . 
       FIG. 2  shows a section of a top view of the filter system  100  from  FIG. 1  illustrating a cross-section of filter system  100 . A filter material  120  is disposed between filter media  110  and  112 . In an embodiment, a reinforcement  114  in the form of, for example, a wired framework or gauze, may be included on either side or both sides of filter material  120  to provide support thereof. Filter material  120  includes an absorbent material  130 . In an embodiment, filter material  120  is in the form of an absorbent fill (e.g., granular pack) that comprises absorbent material  130 . Additionally, as shown in  FIGS. 3 and 4 , filter material  120  may comprise a multi-layered composite pack  122  ( FIG. 3 ),  124  ( FIG. 4 ). The multi-layered composite pack  122 ,  124  may include approximately 2 to 5 layers of composite absorbent material  130  included therein. In either case, the filter material  120  includes a surface  128  for exposing the absorbent material  130  to a fluid passing there through. Surface  128  can comprise any configuration that provides a surface for exposing absorbent material  130  to a fluid passing there through within the confines of the curvature of the concentric casing  116  ( FIG. 1 ). 
     When filter material  120  comprises one or more layers, surface  128  may include, but is not limited to: a flat configuration or an undulating configuration. For example,  FIG. 3  shows a multi-layered composite pack  122  with an undulating (e.g., fluted) configuration  126  for exposing filter material  120  in multi-layered composite pack  122  to a fluid passing there through. It is understood that surface  128  can comprise other types of undulating configurations, such as pleated, regular wave-like, irregular wave-like, and/or the like.  FIG. 4  shows an alternative multi-layered composite pack  124  with a flat configuration  127 , which may be adapted to, for example, the curvature of the concentric casing  116  ( FIG. 1 ). Returning to  FIG. 2 , when filter material  120  comprises an absorbent fill, the surface can be formed using, for example, reinforcement(s)  114 , or the like. 
     Absorbent material  130  may include one or more absorbent materials including, but not limited to: activated carbon, molecular sieve, sodium dihydrate, quartz, magnesium oxide, sodium sesquicarbonate dihydrate (Na 2 CO 3 .NaHCO 3 .2H 2 O), aluminum oxide, sodium oxide, silicon oxide, carbon, and/or the like. Activated carbon may be a vapor phase activated carbon (from coal), for example, AP4-60 (4 mm activated carbon pellet) offered by Calgon Carbon Corporation. An alternative to sesquicarbonate dihydrate may be sodium tartrate dihydrate (Na 2 C 4 H 4 06.2H 2 0). In one embodiment, filter material  120  may include substantially equal parts (by percentage volume) of activated carbon and molecular sieve. In another embodiment, absorbent material  130  may include substantially equal parts of molecular sieve and sodium dihydrate. Another embodiment of absorbent material  130  may include substantially all activated carbon. 
     Other embodiments of absorbent material  130  may include various combinations of several of the absorbent materials described above. In one embodiment, absorbent material  130  comprises a combination of: approximately (0-4)% by volume of quartz; approximately (0-5)% by volume of magnesium oxide; approximately (9-15)% by volume of sodium sesquicarbonate dihydrate; approximately (10-16)% by volume of aluminum oxide; approximately (10-16)% by volume of sodium oxide; approximately (21-27)% by volume of silicon oxide; and approximately (32-38)% by volume of carbon. In another embodiment, absorbent material  130  may include a combination of: approximately 1% by volume of quartz, approximately 2% by volume of magnesium oxide, approximately 12% by volume of sodium sesquicarbonate dihydrate (Na 2 CO 3 .NaHCO 3 .2(H 2 O)), approximately 13% by volume of aluminum oxide, approximately 13% by volume of sodium oxide, approximately 24% by volume of silicon oxide, and approximately 35% by volume of carbon. It is understood that this combination is only illustrative. To this extent, one or more of the percentages could be varied. For example, a combination could include more sodium sesquicarbonate dihydrate and less carbon. The compositions in these embodiments may be modified to include activated carbon, molecular sieve and/or sodium dihydrate. 
     In one embodiment, activated carbon may include carbon pellets. Molecular sieve may include zeolite or other porous material. An embodiment of filter material  120  has demonstrated an ability to remove at least approximately 40% by volume of the hydrogen sulfide (H 2 S) from a fluid passing there through, and may remove hydrogen sulfide from the fluid up to as high as approximately 99.5% by volume. For example, a gas including 50 parts per million (ppm) hydrogen sulfide exited an embodiment of filter system  100  ( FIG. 1 ) including only 0.4 ppm hydrogen sulfide. 
     Referring to  FIG. 2 , in operation, a fluid, which may include, inter alia, hydrogen sulfide (H 2 S), enters through perforations  108  ( FIG. 1 ) of the center of inner core casing wall  104  and passes through first filter media  110  where particulates are removed (e.g., coalesced). From first filter media  110 , the fluid passes through filter material  120 , which filters one or more chemicals, including H 2 S, before flowing to second filter media  112 . Second filter media  112  provides further removal of the particulates (e.g., coalescing and migration protection) from the fluid that passes there through. Filtered fluid is allowed to flow through perforations  108  of outer casing wall  102  for further processing (e.g., treatment, collection, storage, and/or the like). 
     The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. Any embodiment disclosed herein is for the purposes of explaining the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure and is not intended to be limiting to the particular use contemplated.