Recovery of catalytic efficiency for catalytic filter bags from hydrocarbon and ammonium bisulfate fouling

Abstract

A catalytic flue gas filter medium treatment system is provided comprising a catalytic flue gas filter medium, a hydrocarbon foulant removal element, and an ammonium bisulfate (ABS) foulant removal element. The catalytic flue gas filter medium is contaminated with at least one of hydrocarbon foulants and ABS foulants. The hydrocarbon foulant removal element and the ABS foulant removal element are configured to remove hydrocarbon and ABS foulants from the catalytic flue gas filter medium to recover catalytic activity of the catalytic flue gas filter medium.

Description

450385.0068023015W001 RECOVERY OF CATALYTIC EFFICIENCY FOR CATALYTIC FILTER BAGS FROM HYDROCARBON AND AMMONIUM BISULFATE FOULING CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of Provisional Application No. 63 / 742,725, filed January 7, 2025, which is incorporated herein by reference in its entirety for all purposes.FIELD

[0002] The present disclosure relates generally to a system and a method for cleaning a contaminated catalytic flue gas filter medium to recover catalytic efficiency of the catalytic flue gas filter medium.BACKGROUND

[0003] Plants, such as coal-fired power generation plants, municipal waste incinerators, and oil refineries, generate large amounts of flue gases that contain substantial varieties and quantities of environmental pollutants, nitrogen oxides (NOx compounds), mercury (Hg) vapor, sulfur dioxide (SO2), and particulate matters (PM). In the United States, burning coal alone generates about 27 million tons of SO2 and 45 tons of Hg each year. Flue gas treatment systems are used to remove NOx compounds, sulfur oxides, mercury vapor, and fine particulate matters from industrial flue gases using a catalytic flue gas filter medium. However, over time, the catalyst of the filter medium loses efficiency. Thus, there is a need for improvements in systems and methods for recovering catalyst efficiency of the filter medium.SUMMARY

[0004] Catalytic flue gas filter medium treatment systems are provided. These systems may be used in plants that produce flue gas. The flue gas may be filtered through the catalytic flue gas filter medium to remove particulates and other contaminants from the flue gas stream. After a period of time, the catalytic activity of the catalytic flue gas filter medium may be reduced from an initial catalytic activity. The catalytic flue gas filter medium treatment system may be used to regenerate the catalytic activity of the catalytic flue gas filter medium.

[0005] According to an example (Example 1), a catalytic flue gas filter medium treatment system for treating a catalytic flue gas filter medium contaminated with at least one of hydrocarbon foulants and ammonium bisulfate (ABS) foulants, includes a hydrocarbon foulant removal element and an ABS foulant removal element. The hydrocarbon foulant removal element is configured to introduce an oxidant capable of oxidizing and removing the hydrocarbon foulant on the catalytic flue gas filter medium. The ABS foulant removal element is configured to introduce a fluid phase capable of removing the ABS foulant on the catalytic flue DMS_US.368747079.2450385.0068023015W001 gas filter medium. Further, the fluid phase is an aqueous liquid, gas, mixture of reactive gases, or combination thereof.

[0006] According to another example (Example 2), further to Example 1, the hydrocarbon foulant removal element is configured to remove the hydrocarbon foulants at least one of prior to the ABS foulant removal element removing the ABS foulants or simultaneous with the ABS foulant removal element removing ABS foulants.

[0007] According to another example (Example 3), further to either Example 1 or Example 2, the hydrocarbon foulant removal element includes a gas feed stream capable of introducing ozone.

[0008] According to another example (Example 4), further to any one of Examples 1-3, the ABS foulant removal element is one of a liquid feed stream and a container configured to contact the catalytic flue gas filter medium with the fluid phase. The fluid phase is an aqueous solution.

[0009] According to another example (Example 5), further to any one of Examples 1-3, the ABS foulant removal element is a fluid stream including the fluid phase. The fluid phase is a mixture of reactive gases.

[0010] According to another example (Example 6), further to any one of Examples 1-5, the catalytic flue gas filter medium has a deNOx catalytic activity (%) measured by:((NOin — NOout) / NOin)‘ 100NOin is the concentration of NO in a flue gas stream on an upstream side of the catalytic flue gas filter medium and NOout is the concentration of NO in the flue gas stream on a downstream side of the catalytic flue gas filter medium.

[0011] According to another example (Example 7), further to Example 6, an initial deNOx catalytic activity is the deNOx catalytic activity measured before treatment by the catalytic flue gas treatment system and a post foulant removal deNOx catalytic activity is the deNOx catalytic activity measured after treatment by the catalytic flue gas treatment system.

[0012] According to another example (Example 8), further to Example 7, the post foulant removal deNOx catalytic activity is at least 5% greater than relative to the initial deNOx catalytic activity.

[0013] According to another example (Example 9), further to any one of Examples 1-8, the catalytic flue gas filter medium is housed in a filter baghouse.

[0014] According to another example (Example 10), a plant includes a combustion system producing a contaminated flue gas and the catalytic flue gas treatment system of any one of Examples 1-9.450385.0068023015W001

[0015] According to another example (Example 11), a method of regenerating the catalytic activity of a catalytic flue gas filter medium, the method includes: providing the catalytic flue gas treatment system of any one of Examples 1-9 in a plant having a combustion system producing a contaminated flue gas.

[0016] According to another example (Example 12), a method of using a catalytic flue gas filter medium treatment system to recover deNOx catalytic activity in a catalytic flue gas filter medium, includes: (A) providing a catalytic filter medium; (B) determining an initial deNOx catalytic activity of the catalytic filter medium by measuring the deNOx catalytic activity (%); (C) contacting the catalytic filter medium with a hydrocarbon foulant removal element; (D) contacting the catalytic filter medium with an ammonium bisulfate (ABS) foulant removal element following (C); and determining a post foulant removal deNOx catalytic activity of the catalytic filter medium by measuring the deNOx catalytic activity (%) following (D). The catalytic filter medium is contaminated with at least one of hydrocarbon foulants and ABS foulants. deNOx catalytic activity of the catalytic filter medium is determined by measuring the deNOx catalytic activity (%) by:((N0in-N0out) / N0in)-I00wherein NOin is the concentration of NO in a flue gas stream on an upstream side of the catalytic flue gas filter medium and NOout is the concentration of NO in the flue gas stream on a downstream side of the catalytic flue gas filter medium. The hydrocarbon foulant removal element includes an oxidant configured to oxidize and remove hydrocarbon foulants. The ABS foulant removal element includes a fluid phase capable of removing ammonium bisulfate foulants. The post foulant removal deNOx catalytic activity is at least 5% greater than the initial deNOx catalytic activity.

[0017] According to another example (Example 13), further to Example 12, the hydrocarbon foulant removal element in step (C) includes an amount of ozone. Contacting the catalytic filter medium with the hydrocarbon foulant removal element includes partially or fully oxidizing the hydrocarbon foulants.

[0018] According to another example (Example 14), further to Example 13, the concentration of ozone is from 1 ppm to 50000 ppm.

[0019] According to another example (Example 15), further to any one of Examples 12-14, the fluid phase includes an amount of at least one of an aqueous solution and a mixture of reactive gases. Contacting the catalytic filter medium with the ABS foulant removal element includes partially or fully removing ABS foulants.

[0020] According to another example (Example 16), further to Example 15, the fluid phase is an aqueous solution. An amount of the aqueous solution is 5 ml to 100000 ml.450385.0068023015W001

[0021] According to another example (Example 17), further to Example 15, the fluid phase is a mixture of reactive gases. The mixture of reactive gases is from 1 ppm to 500 ppm of NO and 1 ppm to 500 ppm of NO2.

[0022] According to another example (Example 18), further to any one of Examples 12-17, the catalytic filter medium is housed in a filter baghouse.

[0023] According to another example (Example 19), a flue gas filter medium treatment system, configured to regenerate a catalytic activity of and filtering flue gas, includes: a first portion of the treatment system configured to filter a flue gas stream; a second portion of the treatment system configured to regenerate a catalytic activity of a filter medium; a hydrocarbon foulant removal element configured to introduce an oxidant stream comprising an oxidant capable of oxidizing and removing hydrocarbon foulants on the filter medium; and an ammonium bisulfate (ABS) foulant removal element configured to introduce a fluid phase capable of removing the ABS foulant on the filter medium. The fluid phase is an aqueous liquid, gas, mixture of reactive gases, or combination thereof.

[0024] According to another example (Example 20), further to Example 19, the first portion of the treatment system filters out particulates from the incoming flue gas stream forming a particulate-free flue gas stream. At least a portion of the particulate-free flue gas stream is recirculated into the second portion of the treatment system through a recirculated stream. The oxidant stream is introduced into the recirculated stream and is capable of removing hydrocarbon foulants on the filter medium to regenerate the catalytic activity of the filter medium in the second portion of the treatment system.

[0025] According to another example (Example 21), further to Example 20, the first portion of the treatment system is a first filter baghouse and the second portion of the treatment system is a second filter baghouse. The incoming flue gas stream flows into an inlet of the first filter baghouse and the recirculated flue gas stream flows out of the first filter baghouse and into the second filter baghouse.

[0026] According to another example (Example 22), further to Example 20, the first portion of the treatment system is a first portion of the filter medium and the second portion of the treatment system is a second portion of the filter medium. The incoming flue gas stream flows through the first portion of the filter medium and the recirculated flue gas stream flows through the second portion of the filter medium.

[0027] According to another example (Example 23), further to any one of Examples 20-22, the ABS foulant removal element introduces the fluid phase into the recirculated stream.450385.0068023015W001BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above-mentioned and other features and advantages of this disclosure, and the manner of obtaining them, will become more apparent, and will be better understood by reference to the following description of the exemplary embodiments taken in conjunction with the accompanying drawings, wherein:

[0029] FIG. 1 A depicts an exemplary a filter baghouse comprising a filter medium according to some embodiments of the present disclosure;

[0030] FIG. IB depicts a filter medium according to some embodiments of the present disclosure;

[0031] FIG. 1C depicts a porous catalytic layer according to some embodiment of the present disclosure;

[0032] FIG. 2 is a flow chart of the method of using the catalytic flue gas filter medium treatment system of the present disclosure to increase catalytic activity of the filter medium;

[0033] FIG. 3 is an illustration of a first embodiment of an exemplary filter baghouse system using the catalytic flue gas filter medium treatment system of the present disclosure;

[0034] FIG.4 is an illustration of a second embodiment of an exemplary filter baghouse system using the catalytic flue gas filter medium treatment system of the present disclosure; and

[0035] FIG. 5 is an illustration of a third embodiment of an exemplary filter baghouse system using the catalytic flue gas filter medium treatment system of the present disclosure.

[0036] Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of various features and components according to the present disclosure, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present disclosure. The exemplification set out herein illustrates an embodiment of the disclosure, and such an exemplification is not to be construed as limiting the scope of the disclosure in any manner.DETAILED DESCRIPTION

[0037] For the purposes of promoting an understanding of the principles of the present disclosure, reference is now made to the embodiments illustrated in the drawings, which are described below. The exemplary embodiments disclosed herein are not intended to be exhaustive or to limit the disclosure to the precise form disclosed in the following detailed description. Rather, these exemplary embodiments were chosen and described so that others skilled in the art may utilize their teachings.450385.0068023015W001

[0038] Among those benefits and improvements that have been disclosed, other objects and advantages of this disclosure will become apparent from the following description taken in conjunction with the accompanying figures. Detailed embodiments of the present disclosure are disclosed herein; however, it is to be understood that the disclosed embodiments are merely illustrative of the disclosure that may be embodied in various forms. In addition, each of the examples given regarding the various embodiments of the disclosure which are intended to be illustrative, and not restrictive.

[0039] Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases "in one embodiment," “in an embodiment,” and "in some embodiments" as used herein do not necessarily refer to the same embodiment s), though it may. Furthermore, the phrases "in another embodiment" and "in some other embodiments" as used herein do not necessarily refer to a different embodiment, although it may. All embodiments of the disclosure are intended to be combinable without departing from the scope or spirit of the disclosure.

[0040] As used herein, the term "based on" is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meaning of "a," "an," and "the" include plural references. The meaning of "in" includes "in" and "on."

[0041] Among those benefits and improvements that have been disclosed, other objects and advantages of this disclosure will become apparent from the following description taken in conjunction with the accompanying figures. Detailed embodiments of the present disclosure are disclosed herein; however, it is to be understood that the disclosed embodiments are merely illustrative of the disclosure that may be embodied in various forms. In addition, each of the examples given regarding the various embodiments of the disclosure which are intended to be illustrative, and not restrictive.

[0042] Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases “in one embodiment,” “in an embodiment,” and “in some embodiments” as used herein do not necessarily refer to the same embodiment s), though it may. Furthermore, the phrases “in another embodiment” and “in some other embodiments” as used herein do not necessarily refer to a different embodiment, although it may. All embodiments of the disclosure are intended to be combinable without departing from the scope or spirit of the disclosure.

[0043] All prior patents, publications, and test methods referenced herein are incorporated by reference in their entireties.450385.0068023015W001

[0044] As used herein, the term “flue gas stream” refers to a gaseous mixture that comprises at least one byproduct of an industrial process (such as, but not limited to, a coal combustion process, incineration of waste, steel production, cement production, lime production, glass production, industrial boilers, and marine propulsion engines). In some embodiments, a flue gas stream may include at least one gas in an elevated concentration relative to a concentration resulting from the combustion process. For instance, in one non-limiting example, a flue gas stream may be subjected to a “scrubbing” process during which water vapor may be added to the flue gas. Accordingly, in some such embodiments, the flue gas stream may include water vapor in an elevated concentration relative to the initial water vapor concentration due to combustion. Similarly, in some embodiments, a flue gas stream may include at least one gas in a lesser concentration relative to an initial concentration of the at least one gas output from the combustion process. This may occur, for example, by removing at least a portion of at least one gas after combustion. In some embodiments, a flue gas may take the form of a gaseous mixture that is a combination of byproducts of multiple combustion processes.

[0045] As used herein, the term “flow through” means that a flue gas stream is flowed transverse to a cross section of the at least one filter medium, such that the flue gas stream passes through a cross section of the at least one filter medium. In some embodiments of a “flow through” configuration, the flue gas stream is flowed perpendicular to a cross-section of the at least one filter medium.

[0046] As used herein “upstream” refers to a location of a flue gas stream before entering a filter medium. In the “flow through” context, “upstream” may refer to the location of a flue gas stream before entering a cross section of a filter medium.

[0047] As used herein “downstream” refers to a location of a flue gas stream after exiting a filter medium. In the “flow through” context, “downstream” may refer to the location of a flue gas stream after exiting a cross section of a filter medium.

[0048] As used herein, the term “NOx compound” refers to any oxide of nitrogen. In some non-limiting embodiments, “NOx compound” may specifically refer to gaseous oxides of nitrogen that are known environmental pollutants.

[0049] As used herein, the term “deNOx” refers to a process to reduce nitrogen oxides (NOx) emissions from flue gas. NOx compounds, which include nitric oxide (NO) and nitrogen dioxide (NO2) may be pollutants and / or foulants for catalytic flue gas treatment systems.

[0050] As used herein, an “oxidizing agent” refers to any agent used in a redox reaction that transfers electrons between reactants. The oxidizing agent may gain electrons and be reduced during a chemical reaction.

[0051] I. Catalytic Flue Gas Filter Medium450385.0068023015W001

[0052] The catalytic flue gas filter medium (or “filter medium” or “catalytic filter medium”) may comprise at least one filter medium.

[0053] Figures 1A-1C depict non-limiting embodiments of a catalytic flue gas filter medium according to the present disclosure.

[0054] Referring to Figure 1 A, in some embodiments, at least one filter medium 101, or “filter bag,” may be housed in at least one filter baghouse 100. A flue gas stream 102 may flow through the at least one filter medium 101 by passing through cross section A. Once the flue gas stream 102 flows through the at least one filter medium 101, the outgoing flue gas stream 112 may exit the at least one filter baghouse, as indicated by the vertically oriented arrows. An upstream direction 103 is defined in terms of the prevailing direction of incoming fluid flow 102, and a downstream direction 104 is defined in terms of a prevailing direction of outgoing fluid flow 104. As shown in Figure 1 A, the upstream side 103 of the filter medium 101 may, in some embodiments, correspond to an outside of a filter baghouse, such as filter baghouse 100.Likewise, downstream side 104 of the filter medium 101 may correspond to an inside of a filter baghouse, such as filter baghouse 100.

[0055] Figure IB depicts an exemplary filter medium 101 according to some embodiments of the present disclosure. As shown in Figure IB, a flue gas stream 102, which may comprise hydrocarbon, SO2 andNOx compounds and solid particulates 107, may flow through cross section A (as shown in Figure 1 A) from an upstream side 103 of the filter medium 101 to a downstream side 104 of the filter medium. In some embodiments, filter medium 101 may include at least one porous protective layer 106 and at least one felt batt 108 on the upstream side 103 the of the filter medium 101 In some embodiments, the at least one felt batt 108 may be positioned on a porous catalytic film 105. In some embodiments, the combination of the at least one felt batt 108 and the porous catalytic film 105 may be referred to as a porous catalytic layer 111.

[0056] In one embodiment, the filter medium 101 and components thereof can be described in terms of an upstream side 103 facing an incoming fluid flow 102, and a downstream side 104 from which an outgoing fluid flow 112 originates. Figure IB shows a porous catalytic film 105 layered with a first felt batt 108 and a protective porous layer 106 in an upstream direction 103 from the porous catalytic film 105; with a supportive scrim 109 and a second felt batt 114 positioned in a downstream direction 104. The filter medium 101 is capable of filtering particulates 107, which may be suspended in the incoming fluid flow 102 and also to reduce or remove chemical contaminants via a catalyzed reaction at the porous catalytic film 105 in the porous catalytic layer 111.450385.0068023015W001

[0057] The porous catalytic film 105 includes an intact portion 116 broken by perforations 118. The perforations 118 can be formed by way of a needling operation; or alternatively, by needle punching operation. The construction of the adjacent porous catalytic film 105 and first felt batt 108 provide for circulation of the incoming fluid flow 102 within the internal structure of the first felt batt, near the enmeshed catalytic particles of the porous catalytic film 105, prior to the fluid passing through the porous catalytic film 105 at the perforations 118 or via pores in the intact portion 116.

[0058] In one embodiment, a porous protective layer 106 is positioned on an upstream side of the first felt batt 108 and is capable to capturing or preventing ingress of particulates 107. The porous protective layer 106 can capture particulates (e.g., dust, soot, ash, or the like) to prevent entry of particles into the porous catalytic film 105 or felt batt 108 to prevent or minimize clogging of the perforations 118 of the film and prevent or minimize fouling of the porous polymer membrane that might block access to the supported catalytic particles enmeshed therein. The porous protective layer 106 can collect the particulates 107 in a film or cake that can be readily cleaned from the porous protective layer 106, thus providing for easy maintenance of the filter medium 101. The porous protective layer 106 can be constructed from any suitable porous membrane material, such as but not limited to a porous woven or nonwoven membrane, a PTFE woven or nonwoven, an ePTFE membrane, a fluoropolymer membrane, or the like. The porous protective layer 106 can be connected with the first felt batt 108 by way of laminating, heat treating, discontinuous or continuous adhesives, or other suitable joining method.

[0059] In accordance with at least one embodiment, the porous catalytic film 105 is supported by a scrim 109 that provides structural support without significantly affecting the overall fluid permeability of the filter medium 101. The scrim 109 can be any suitable, porous backing material capable of supporting the filter medium 101. The scrim can be, for example, a fluoropolymer woven or nonwoven, a PTFE woven or nonwoven, or in one specific embodiment, a woven made from ePTFE fibers (e.g., 440 decitex RASTEX® fiber, available from W. L. Gore and Associates, Inc., Elkton, MD.). The scrim 109 may be disposed downstream 104 of the porous catalytic film 105, e.g., downstream and adjacent the porous catalytic film 105, or alternatively, downstream and separated from the porous catalytic film 105 by one or more additional layers. Scrim 109 may be connected to the porous catalytic film 105 by a needling or needle punching operation. The scrim 105 may also, or alternatively, be connected with the porous catalytic film 105 by way of a heat treatment, by one or more connectors that press the layers together, or by an adhesive, e.g., a thin adhesive layer (which may be continuous or discontinuous) between the scrim 105 and porous catalytic film 105, or by any suitable combination of two or more of the above methods, including a needling or needle450385.0068023015W001 punching operation. Generally, the scrim 109 has higher air permeability than the porous catalytic film 105.

[0060] In one embodiment, the filter medium 101 can further include a second felt batt 114 positioned in the downstream direction 104 from the porous catalytic film 105. The second felt batt 114 can have a similar construction and dimensions as the first felt batt 108, e.g., the second felt batt can include or be composed of any suitable woven or nonwoven, such as but not limited to a staple fiber woven or nonwoven, a PTFE staple fiber woven or nonwoven, or a fluoropolymer staple fiber woven or nonwoven. For example, the second felt batt 114 can be a PTFE fiber felt or a PTFE fiber fleece.

[0061] The porous catalytic film 105, scrim 109, and the first and second felt batts 108, 114 may be connected together via a needling or needle punching operation, or a combination of these techniques. In one embodiment, the porous catalytic film 105 alone is perforated because the perforations provide for suitable fluid flow across the porous catalytic film 105, whereas the other layers are generally more permeable to airflow than the porous catalytic film 105 and do not require any perforation. Some or all of the layers may be further connected via heat treatment, adhesive, or another suitable connection method. The porous protective layer 106 may be attached to the remaining layers of the filter medium 101 by adhesion, heat treatment, or another method that does not result in perforations of the porous protective layer 106.Alternatively, the porous protective layer 106 can be connected with the remaining layers of the filter medium 101 via needling or needle punching.

[0062] Figure 1C depicts an additional non-limiting exemplary embodiment of a filter medium 101. As shown, filter medium 101 may comprise a porous catalytic layer 111. In some non-limiting embodiments, filter medium 101 may take the form of a filter bag. In some embodiments the porous catalytic layer 111 may be coated with a catalyst material (not shown in Figure 1C) such as catalyst particles. In some embodiments, the catalyst material may be attached to the porous catalytic layer 111 by one or more adhesives described herein (not shown). The porous catalytic layer 111 includes a porous catalytic film 105 and a felt batt 108. An upstream direction 103 is defined in terms of the prevailing direction of incoming fluid flow 102, and a downstream direction 104 is defined in terms of a prevailing direction of outgoing fluid flow 112. The felt batt 108 is positioned upstream of the porous catalytic film 105, and is operable to collect particulates 107 (e.g., dust and the like) from the incoming fluid flow 102. In some embodiments described herein, the porous catalytic film 105 comprises perforations therein. The perforated porous catalytic film 105 permits fluid to pass readily through the catalytic composite while still interacting sufficiently with the supported catalyst particles durably enmeshed within the porous polymer membrane to remediate contamination in the fluid450385.0068023015W001 stream. The catalytic material of the porous catalytic film 105 is selected to target specific contaminant species. For example, the supported catalyst particles of the porous catalytic film 105 can include some combination of, or all of, the catalytic species TiO2, V2O5, WO3, suitable for catalyzing the reduction or removal of NOx species such as NO, NO2, to water and nitrogen gas, as illustrated in Figure 1C. However, other catalytic materials may be substituted or included that are suitable for conversion of different contaminants, e.g., for remediating carbon monoxide (CO), Dioxin / Furan, ozone (03), volatile organic compounds (VOC), and other contaminants.

[0063] The felt batt 108 can include any suitable, porous structure capable of filtering particulate contaminants 107; as well as moderating the incoming fluid flow 102 for introduction to the porous catalytic film 105. The felt batt 108 can be formed of any suitable woven or nonwoven having a highly porous interior structure, such as, but not limited, to a staple fiber woven or nonwoven, a PTFE staple fiber woven or nonwoven, a fleece formed from a fluoropolymer staple fiber, or a fluoropolymer staple fiber woven or nonwoven. In one embodiment, the felt batt 105 is a PTFE fiber felt, or a PTFE fiber fleece.

[0064] In at least one embodiment, the component layers of the porous catalytic layer 111 are connected together by way of the needling or needle-punching operation, i.e., a needle or punch can be pressed through both of the assembled felt batt 108 and porous catalytic film 105 in order to locally deform the layers to hold the layers in contact with each other. In general, a needling operation penetrates and deforms the material, while a needle punching operation also removes a small plug of material; but both operations may be referred to as “needling”. Layers in the porous catalytic layer 111 may also be held together by lamination or applied heat treatment, by adhesives (typically discontinuous adhesives so as to retain porosity), by external connectors, by weaving or other comparable connective means, or by any suitable combination of the above. In one embodiment, the component layers of the porous catalytic layer 111 are combined by needling and / or needle punching, followed by a subsequent heat treatment to set the composite and form the catalytic composite. Alternatively, the component layers of the porous catalytic layer 111 can be combined by pressing the layers together after the perforations have been applied to the porous catalytic film 105, and subsequently heat treating the layered assembly to form the catalytic composite.

[0065] The filter medium may be contaminated with hydrocarbon foulants and ammonium bisulfate (ABS) foulants. As flue gas from a plant or other source of flue gas flows through the filter medium to filter out NOx and particulates, the filter medium may become contaminated with hydrocarbons and ammonium bisulfate, decreasing the catalytic efficiency450385.0068023015W001 and activity of the filter medium. The catalytic activity may be recovered using the system of the present disclosure.

[0066] II. A Catalytic Flue Gas Filter Medium Treatment System

[0067] The present disclosure provides a catalytic flue gas filter medium treatment system comprising a catalytic flue gas filter medium (discussed above), a hydrocarbon foulant removal element, and an ammonium bisulfate (ABS) foulant removal element.

[0068] As shown in FIG. 3, a catalytic flue gas filter medium 101 within a filter baghouse 100 may gradually become contaminated from flue gas 102 flowing through filter medium 101. As filter medium 101 becomes contaminated, the catalyst layer may lose activity. To regenerate the activity, the catalytic flue gas filter medium treatment system 300 of the present disclosure may be used.

[0069] The catalytic flue gas filter medium treatment system 300 may be used in plants that include one filter baghouse 100 or two or more filter baghouses 100, 100*. The embodiment shown in FIG. 3 comprises a system 300 that utilizes a first filter baghouse 100* and a second filter baghouse 100.

[0070] The catalytic flue gas filter medium treatment system 300 comprises a hydrocarbon foulant removal element 120 and an ABS foulant removal element 122, each discussed below.

[0071] A. Catalyst Recovery of Filter Medium

[0072] The efficiency and / or activity of the catalytic flue gas filter medium may be measured by calculating the deNOx catalytic activity (%) of the filter medium. The deNOx activity may be measured using continuous emission monitor systems (CEMS) and calculated using Equation I:((NOin — NOout) / NOin)‘ 100Equation Iwherein NOin is the concentration of NO in a flue gas stream on an upstream side of the catalytic flue gas filter medium and NOout is the concentration of NO in the flue gas stream on a downstream side of the catalytic flue gas filter medium.

[0073] During use of the filter medium to clean flue gas, the filter medium may become contaminated with foulants, such as hydrocarbons and ABS. The deNOx catalytic activity of the filter medium may be reduced.

[0074] To recover catalytic activity, the catalytic filter medium treatment system of the present disclosure may be used.

[0075] A filter medium contaminated with hydrocarbon and / or ammonium bisulfate (ABS) foulants may have an initial deNOx catalytic activity (also known as the “first deNOx450385.0068023015W001 catalytic activity”) and a post foulant removal deNOx activity (also known as the “second deNOx catalytic activity”). The initial deNOx catalytic activity is the deNOx catalytic activity measured before treatment by the catalytic flue gas treatment system and the post foulant removal deNOx catalytic activity is the deNOx catalytic activity measured after treatment by the catalytic flue gas treatment system. The post foulant removal deNOx catalytic activity may be greater than the initial deNOx catalytic activity by at least 5%, at least 10%, at least 15%, at least 20%, or any range using any two of the foregoing values as endpoints, such as from about 5-20%, or from about 10-15%.

[0076] B. Hydrocarbon Foulant Removal Element

[0077] The catalytic flue gas filter medium treatment system 300 may comprise a hydrocarbon foulant removal element 120. The hydrocarbon foulant removal element may comprise at least one oxidant 121. The at least one oxidant 121 may be configured to oxidize and remove hydrocarbon foulants on the catalytic flue gas filter medium 101.

[0078] The hydrocarbon foulant removal element 120 may introduce the oxidant 121 into the filter baghouse 100. The oxidant 121 may be a reactive molecule with a strong oxidizing ability due to extra oxygen atoms. The oxidant 121 reacts with carbon-carbon double bonds in unsaturated hydrocarbons in the filter medium. This reaction breaks the hydrocarbon molecules into smaller, less complex compounds, such as carbon dioxide, water, and other oxidized byproducts. The smaller oxidized by products may then be removed from the filter medium through a flue gas exhaust on the downstream side of the filter medium.

[0079] The hydrocarbon foulant removal element 120 may partially or completely oxidize and remove hydrocarbons from the flue gas. The at least one oxidant 121 may comprise or be selected from the group of: hydrogen peroxide (H2O2), ozone (O3), hydroxyl radical, at least one organic peroxide, at least one metal peroxide, at least one peroxy-acid, at least one percarbonate salt, at least one perborate salt, at least one persulfate salt, at least one permanganate salt, at least one hypochlorite salt, chlorine dioxide (CIO2), at least one chlorate salt, at least one perchlorate salt, at least one hypochlorite salt, perchloric acid (HC1O4), at least one bismuthate salt, any aqueous solution comprising at least one of the foregoing, or any combination thereof. In one embodiment, the at least one oxidant is ozone.

[0080] In some embodiments, the hydrocarbon foulant removal element 120 may be a gas feed stream comprising ozone in a concentration from about Ippm, 5ppm, lOppm, 50ppm, or lOOppm to 500ppm, lOOOppm, 5000ppm, lOOOOppm, or 50000ppm, or any range using any two of the foregoing values as endpoints, such as from about Ippm to about 50000ppm, from about 5ppm to about lOOOOppm, from about lOppm to about 5000ppm, from about 50ppm to about lOOOppm, or from about lOOppm to about 500ppm.450385.0068023015W001

[0081] The hydrocarbon foulant removal element 120 may be configured to remove the hydrocarbon foulants prior to the removal of ABS foulants by the ABS foulant removal element 122. Alternatively, the hydrocarbon foulant removal element 120 may be configured to remove the hydrocarbon foulants simultaneously with the removal of ABS foulants by the ABS foulant removal element 122.

[0082] C. ABS foulant Removal Element

[0083] The catalytic flue gas filter medium treatment system 300 may comprise an ABS foulant removal element 122 configured to “wash” the filter baghouse / filter medium by introducing a fluid phase 123 capable of removing ABS foulants on the catalytic flue gas filter medium 101. Ammonium bisulfate is a by-product that can form when ammonia reacts with sulfur oxides in the flue gas. These foulants can cause operational issues, such as clogging and corrosion. The ABS foulant removal element may be a feed stream and a container configured to contact the catalytic flue gas filter medium with the fluid phase. The ABS foulant removal element 122 may introduce the fluid phase 123 into the filter baghouse 100. The fluid phase 123 may dissolve or react with the ammonium bisulfate, breaking it down into smaller non-fouling components. The components may then be washed off of the filter medium 101 with airflow, or mechanical and chemical washing.

[0084] The fluid phase may be an aqueous solution such as a liquid, gas, mixture of reactive gases, or a combination thereof. In one embodiment, the fluid phase may be ozone, such as the ozone used in the hydrocarbon foulant removal element. In this embodiment, the ozone may be used to oxidize a portion of NO in the gas stream to NO2 to form the reactive gas to remove ABS foulants.

[0085] When the fluid phase is a liquid aqueous solution, the volume of fluid phase may be from about 5 ml, about 10 ml, about 100 ml, or about 1000 ml to about 5000 ml, about 10000 ml, about 50000 ml, or 100000 ml, or any range using any two of the foregoing values as endpoints, such as about 5 ml to about 100000 ml, about 10 ml to about 50000 ml, about 100 ml to about 10000 ml, or about 1000 ml to about 5000 ml.

[0086] When the fluid phase is a mixture of reactive gases, the fluid phase may comprise a concentration of NO and a concentration of NO2. The concentration of NO in the mixture of gases may be from about Ippm, about 5ppm, or about lOppm to about 50ppm, about lOOppm, or about 500ppm, or any range using any two of the foregoing values as endpoints, such as about Ippm to about 500ppm, about 5ppm to about lOOppm, or about lOppm to about 50ppm. The concentration of NO2 in the mixture of gases may be from about Ippm, about 5ppm, or about lOppm to about 50ppm, about lOOppm, or about 500ppm, or any range using any two of the450385.0068023015W001 foregoing values as endpoints, such as about Ippm to about 500ppm, about 5ppm to about lOOppm, or about lOppm to about 50ppm.

[0087] III. Method

[0088] A plant may comprise the catalytic flue gas filter medium treatment system described above to recover catalytic activity of the filter medium. The plant may comprise a combustion system producing contaminated flue gas.

[0089] The present disclosure further provides a method 200 of using the catalytic flue gas filter medium treatment system to recover deNOx catalytic activity in a catalytic flue gas filter medium, as shown in FIG. 2.

[0090] In a first step (Step A), a catalytic filter medium, as described above, contaminated with at least one of foulants and ABS foulants may be provided.

[0091] Second (Step B), the catalytic filter medium may be contacted with the hydrocarbon foulant removal element. The hydrocarbon foulant removal element may partially or fully oxidize hydrocarbon foulants on the catalytic filter medium.

[0092] Third (Step C), the catalytic filter medium may be contacted with the ABS foulant removal element. The catalytic filter medium may be “washed” with the ABS foulant removal element to remove the ABS foulants on the filter medium

[0093] Step B may happen prior to or simultaneously with Step C, as described above.

[0094] Following Steps B and C, hydrocarbon and ABS foulants may be partially or completely removed from the filter medium, 202. After partial or complete removal of hydrocarbon and / or ABS foulants, the catalytic activity of the filter medium may increase 204. The post foulant removal deNOx catalytic activity may be at least 5% greater, at least 10% greater, at least 15% greater, or at least 20% greater than the initial deNOx catalytic activity of the catalytic filter medium, as calculated according to Equation I above.

[0095] IV. Treatment System Embodiments

[0096] Referring to FIG. 3, a first embodiment of the catalytic flue gas filter medium treatment system 300 (hereinafter “treatment system 300”) is illustrated. The treatment system 300 may comprise a filter medium 101 within a filter baghouse 100, a hydrocarbon removal element 120, and an ABS removal element 122. The treatment system 300 may regenerate the catalytic activity of the filter medium 101 using method 200, as described above. The hydrocarbon removal element 120 may introduce an oxidant stream 121 into filter medium 101 to oxidize hydrocarbons and remove them from filter medium 101. Oxidant stream 121 may comprise ozone.

[0097] Similarly, ABS foulant removal element 122 may introduce a fluid phase 123 into filter medium 101 to wash filter medium of ABS foulants. Fluid phase 123 may be an aqueous450385.0068023015W001 solution such as a liquid, gas, mixture of reactive gases, or a combination thereof. For example, fluid phase 123 may be ozone.

[0098] Both oxidant stream 121 and fluid phase 123 may flow through filter medium 101, removing particulates and foulants from filter medium 101, regenerating the catalytic activity of the filter medium.

[0099] In a second embodiment of the present disclosure, shown in FIG. 4, treatment system 400 may include multiple filter baghouses 100a, 100b. A first filter baghouse 100a may remain online to clean flue gas flowing in from flue gas stream 102. Flue gas stream 102 may be cleaned by a first filter medium 101a, removing particulates from flue gas stream 102 as flue gas stream 102 flows into first filter medium 101a and flows out of first filter baghouse 100a via an outgoing flue gas stream 112. Outgoing flue gas stream 112 may be substantially free from particulates.[000100] Outgoing flue gas stream 112 may split and either flow out an exhaust or into second filter baghouse 100b through a recirculated stream 113.[000101] A second filter baghouse 100b may be taken offline to regenerate the catalytic activity of a second filter medium 101b. Recirculated stream 113 introduces particulate-free flow and is mixed with an oxidant stream 121 from hydrocarbon foulant removal element 120.Oxidant stream 121 may comprise an oxidizing agent, such as ozone. Oxidant stream 121 may enter a second filter medium 101b and completely or partially oxidize hydrocarbon foulants on the filter medium.[000102] Further, the ABS foulant removal element 122 may introduce a fluid phase to remove ABS foulants from the filter medium 101. Fluid phase 123 may be an aqueous solution such as a liquid, gas, mixture of reactive gases, or a combination thereof configured to remove ABS from the filter medium. Hydrocarbon foulant removal element 120 may remove hydrocarbons from second filter baghouse 100b either before ABS foulant removal element 122 removes ABS foulants from the second filter medium 101b, or at the same time ABS foulant removal element 122 removes ABS foulants from the second filter medium 101b.[000103] Because particulates have already been removed from recirculated stream 113, the amount of oxidant and fluid phase needed to recover catalytic activity in the second embodiment of the treatment system 400 may be less than the amount of oxidant and fluid phase needed to recover the same amount of catalytic activity in the first embodiment of the treatment system 300.[000104] After the catalytic activity of second filter medium 101b is regenerated by the catalytic flue gas filter medium treatment system 400, second filter baghouse 100b may be put back online such that flue gas stream 102 flows through one or both the first filter baghouse 100a450385.0068023015W001 and the second filter baghouse 100b to filter the flue gas 102. The first filter medium 101a may be cleaned by reversing the process described above (not shown), taking the first filter baghouse 100a offline to recover the catalytic activity using the catalytic flue gas filter medium treatment system 400, and keeping the second filter baghouse 100b online such that the flue gas stream 102 flows through second filter baghouse 100b, recirculated stream 113 flows into first filter baghouse 100a, and foulant removal elements 120, 122 remove foulants from first filter medium 101a. Treatment system 400 may be used in plants with a plurality of filter baghouses, taking the filter baghouse needing the catalyst regenerated offline to use the catalytic flue gas filter medium treatment system 400 while the remaining filter baghouses continue to filter flue gas and recirculate particulate-free streams into the offline filter baghouse.[000105] A third embodiment of catalytic flue gas filter medium treatment system 500 is shown in FIG. 5. In systems only comprising one filter baghouse, the single filter baghouse may comprise segmented compartments 130a, 130b to allow for flue gas to be cleaned simultaneous to the regeneration of the catalytic activity of the filter medium 101. A first portion of the filter medium 130a may be used to continue to filter flue gas. A second portion of the filter medium 130b may be used to regenerate the catalytic activity of the filter medium 101.[000106] Inflowing Flue gas stream 102a may flow in through an inlet of filter baghouse 100. The first portion of the filter medium 130a may remove particulates from fluid gas stream 102, forming particulate-free stream outgoing stream 112a.[000107] A portion of particulate-free outgoing flue gas 112a may be recirculated as recirculated stream 113a into a second portion of the filter medium 130b, discussed further below.[000108] Recirculated stream 113a may be recirculated into a second portion of filter medium 130b to regenerate the catalytic activity of the second portion of the filter medium 130b. Hydrocarbon foulant removal element 120 may introduce an oxidant stream 121 into stream 113a. Oxidant stream 121b may comprise any oxidant configured to remove hydrocarbons from the filter medium, such as ozone. Further, an ABS foulant removal element may introduce a fluid phase 123 into stream 113. Fluid phase 123 may be an aqueous solution such as a liquid, gas, mixture of reactive gases, or a combination thereof configured to remove ABS from the filter medium. Hydrocarbon foulant removal element 120 may remove hydrocarbons from second portion of the filter medium 130b either before ABS foulant removal element 122 removes ABS foulants from the second portion of the filter medium 130b, or at the same time ABS foulant removal element 122 removes ABS foulants from the second portion of the filter medium 130b.[000109] Once the catalytic activity of the second portion of the filter medium 130b is recovered, treatment system 500 may switch which portion of the filter medium 101 filters flue450385.0068023015W001 gas 102 and which portion regenerates the catalytic activity. For example, inflowing flue gas stream 102b may flow into the filter baghouse 100 such that the second portion of the filter medium 130b filters the flue gas creating particulate-free outgoing flue gas 112b, a portion of particulate-free outgoing glue gas 112b is split off into recirculated stream 113b, recirculated stream 113b is recirculated into the first portion of the filter medium 130a, and the first portion of the filter medium 130a regenerates the catalytic activity of the filter medium 101 by introduction of an oxidant 121 and / or a fluid phase 123 by hydrocarbon foulant removal element 120 and / or ABS foulant removal element 122.[000110] Similar to treatment system 400, treatment system 500 may regenerate the catalytic activity of the filter medium without using as much ozone as the first embodiment of the treatment system 300.[000111] While this disclosure has been described as having an exemplary design, the present disclosure may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practices in the art to which this disclosure pertains.EXAMPLES[000112] deNOx Catalytic Activity[000113] The catalytic composite articles were tested for deNOx catalytic activity recovery (catalytic NOx removal efficiency) from a simulated flue gas. Briefly, a square 4.5 inch (-1.77 cm) x 4.5 inch (-1.77 cm) of catalytic composite article was placed in a sample holder located within a reaction chamber with a gasket on either side. The samples were exposed to an N2 balanced simulated flue gas at 200°C. The simulated flue gas contained 350 ppm nitric oxide (NO), 350 ppm NH3, 6 vol% O2 balanced with N2 with a total flowrate of 4.2 L / min. In order to determine NOx removal efficiency, the upstream and downstream concentration (i.e., relative to the catalytic composite article) of NO were monitored with a MKS MULTI-GAS™ 2030D FTIR analyzer (MKS Instruments, Andover, MA). NOx removal efficiency was calculated according to the following formula where ‘NO’ indicates the concentration of NO in the respective stream.NOx removal efficiency (%) = (NOin - NOout) / NOin x 100%[000114] Example 1[000115] A catalytic composite article was formed according to U.S. Patent No. 11,078,821 B2 to Eves et al. The filter medium included a catalytic composite article having a catalytic layered assembly that included a polytetrafluoroethylene (PTFE) + catalyst composite membrane450385.0068023015W001 having a first, upstream side and a second, downstream side; and one or more felt batts. Each felt batt was formed of fleece formed from PTFE staple fiber. The filter medium was connected by a plurality of perforations formed by a needle punching process, by a needling process, or both.[000116] The polytetrafluoroethylene (PTFE) + catalyst composite membranes of the filter medium described above were prepared using the general dry blending methodology taught in U.S. Patent No. 7,791,861 B2 to Zhong et al. to form composite tapes that were then uniaxially expanded according to the teachings of U.S. Patent No. 3,953,556 to Gore. The resulting porous fibrillated expanded PTFE (ePTFE) composite membranes included supported catalyst particles durably enmeshed and immobilized with the ePTFE node and fibril matrix.[000117] The NOx removal efficiency of the catalytic composite article was determined and recorded in Table 1.[000118] Example 2[000119] The catalytic composite article described in Example 1 was returned from field after exposure to the real flue gas. The deposition of ammonium bisulfate foulant and hydrocarbon foulant on the returned catalytic composite article was confirmed by THERMO SCIENTIFIC™ NICOLET™ iS50 Fourier-transform infrared spectroscopy (FTIR) spectrometer (Thermo Fisher Scientific Inc., Waltham, MA)[000120] The NOx removal efficiency of the catalytic composite article was determined and recorded in Table 1.[000121] Example 3[000122] A catalytic composite article described in Example 2 was used. The catalytic composite article was first soaked in distilled and deionized (DI) water for 4 hours, then dried at room temperature (20-25 °C) oven overnight.[000123] The NOx removal efficiency of the catalytic composite article was determined and recorded in Table 1.[000124] Example 4[000125] A catalytic composite article described in Example 2 was used. The catalytic composite article was exposed to 10000 ppm O3 at 150°C for 2 hours.[000126] The NOx removal efficiency of the catalytic composite article was determined and recorded in Table 1.[000127] Example 5[000128] A catalytic composite article described in Example 2 was used. The catalytic composite article was first soaked in distilled and deionized (DI) water for 4 hours, then dried at room temperature (20-25 °C) overnight. Afterwards, the catalytic composite article was exposed to 1% O3 at 150°C for 2 hours.450385.0068023015W001 [000129] The NOx removal efficiency of the catalytic composite article was determined and recorded in Table 1.[000130] Example 6[000131] A catalytic composite article described in Example 2 was used. The catalytic composite article was first exposed to 10000 ppm O3 at 150°C for 2 hours. Afterwards, the catalytic composite article was soaked in DI water for 4 hours, then dried at room temperature (20-25°C) overnight.[000132] The NOx removal efficiency of the catalytic composite article was determined and recorded in Table 1.Table 1: NOx Removal Efficiency of Catalytic Composites After Various Treatments[000133] The invention of this application has been described above both generically and with regard to specific embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments without departing from the scope of the disclosure. Thus, it is intended that the embodiments cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

450385.0068023015W001 CLAIMSWhat is claimed is:

1. A catalytic flue gas filter medium treatment system for treating a catalytic flue gas filter medium contaminated with at least one of hydrocarbon foulants and ammonium bisulfate (ABS) foulants, comprising:a hydrocarbon foulant removal element configured to introduce an oxidant capable of oxidizing and removing the hydrocarbon foulant on the catalytic flue gas filter medium; and an ABS foulant removal element configured to introduce a fluid phase capable of removing the ABS foulant on the catalytic flue gas filter medium;wherein the fluid phase is an aqueous liquid, gas, mixture of reactive gases, or combination thereof.

2. The catalytic flue gas filter medium treatment system of claim 1, wherein the hydrocarbon foulant removal element is configured to remove the hydrocarbon foulants at least one of prior to the ABS foulant removal element removing the ABS foulants or simultaneous with the ABS foulant removal element removing ABS foulants.

3. The catalytic flue gas filter medium treatment system of either claim 1 or claim 2, wherein the hydrocarbon foulant removal element comprises a gas feed stream capable of introducing ozone.

4. The catalytic flue gas filter medium treatment system of any one of claims 1-3, wherein the ABS foulant removal element is one of a liquid feed stream and a container configured to contact the catalytic flue gas filter medium with the fluid phase;wherein the fluid phase is an aqueous solution.

5. The catalytic flue gas filter medium treatment system of any one of claims 1-3, wherein the ABS foulant removal element is a fluid stream comprising the fluid phase;wherein the fluid phase is a mixture of reactive gases.

6. The catalytic flue gas filter medium treatment system of any one of claims 1-5, wherein the catalytic flue gas filter medium has a deNOx catalytic activity (%) measured by:((NOin — NOout) / NOin)‘ 100450385.0068023015W001 wherein NOin is the concentration of NO in a flue gas stream on an upstream side of the catalytic flue gas filter medium and NOout is the concentration of NO in the flue gas stream on a downstream side of the catalytic flue gas filter medium.

7. The catalytic flue gas filter medium treatment system of claim 6, wherein an initial deNOx catalytic activity is the deNOx catalytic activity measured before treatment by the catalytic flue gas treatment system and a post foulant removal deNOx catalytic activity is the deNOx catalytic activity measured after treatment by the catalytic flue gas treatment system.

8. The catalytic flue gas filter medium treatment system of claim 7, wherein the post foulant removal deNOx catalytic activity is at least 5% greater than relative to the initial deNOx catalytic activity.

9. The catalytic flue gas filter medium treatment system of any one of claims 1-8, wherein the catalytic flue gas filter medium is housed in a filter baghouse.

10. A plant comprising a combustion system producing a contaminated flue gas and the catalytic flue gas treatment system of any one of claims 1-9.

11. A method of regenerating the catalytic activity of a catalytic flue gas filter medium, the method comprising:providing the catalytic flue gas treatment system of any one of claim 1-9 in a plant having a combustion system producing a contaminated flue gas.

12. A method of using a catalytic flue gas filter medium treatment system to recover deNOx catalytic activity in a catalytic flue gas filter medium, comprising:(A) providing a catalytic filter medium, wherein the catalytic filter medium is contaminated with at least one of hydrocarbon foulants and ammonium bisulfate (ABS) foulants;(B) determining an initial deNOx catalytic activity of the catalytic filter medium by measuring the deNOx catalytic activity (%) by;((NOin — NOout) / NOin)‘ 100wherein NOin is the concentration of NO in a flue gas stream on an upstream side of the catalytic flue gas filter medium and NOout is the concentration of NO in the flue gas stream on a downstream side of the catalytic flue gas filter medium;450385.0068023015W001 (C) contacting the catalytic filter medium with a hydrocarbon foulant removal element;wherein the hydrocarbon foulant removal element comprises an oxidant configured to oxidize and remove hydrocarbon foulants; and(D) contacting the catalytic filter medium with an ABS foulant removal element following step (C);wherein the ABS foulant removal element comprises a fluid phase capable of removing ammonium bisulfate foulants; and(E) determining a post foulant removal deNOx catalytic activity of the catalytic filter medium following step (D) by measuring the deNOx catalytic activity (%), wherein the post foulant removal deNOx catalytic activity is at least 5% greater than the initial deNOx catalytic activity.

13. The method of claim 12, wherein the hydrocarbon foulant removal element in step (C) comprises an amount of ozone; andwherein contacting the catalytic filter medium with the hydrocarbon foulant removal element comprises partially or fully oxidizing the hydrocarbon foulants.

14. The method of claim 13, wherein the concentration of ozone comprises 1 ppm to 50000 ppm.

15. The method of any one of claims 12-14, wherein the fluid phase comprises an amount of at least one of an aqueous solution and a mixture of reactive gases;wherein contacting the catalytic filter medium with the ABS foulant removal element comprises partially or fully removing ABS foulants.

16. The method of claim 15, wherein the fluid phase is an aqueous solution;wherein an amount of the aqueous solution is 5 ml to 100000 ml.

17. The method of claim 15, wherein the fluid phase is a mixture of reactive gases, the mixture of reactive gases comprising 1 ppm to 500 ppm of NO and 1 ppm to 500 ppm of NO2.

18. The method of any one of claims 12-17, wherein the catalytic filter medium is housed in a filter baghouse.450385.0068023015W001 19. A flue gas filter medium treatment system, configured to regenerate a catalytic activity of and filtering flue gas, comprising:a first portion of the treatment system configured to filter a flue gas stream;a second portion of the treatment system configured to regenerate a catalytic activity of a filter medium;a hydrocarbon foulant removal element configured to introduce an oxidant stream comprising an oxidant capable of oxidizing and removing hydrocarbon foulants on the filter medium; andan ammonium bisulfate (ABS) foulant removal element configured to introduce a fluid phase capable of removing the ABS foulant on the filter medium;wherein the fluid phase is an aqueous liquid, gas, mixture of reactive gases, or combination thereof.

20. The flue gas filter medium treatment system of claim 19, wherein the first portion of the treatment system filters out particulates from the incoming flue gas stream forming a particulate-free flue gas stream;wherein at least a portion of the particulate-free flue gas stream is recirculated into the second portion of the treatment system through a recirculated stream;wherein the oxidant stream is introduced into the recirculated stream and is capable of removing hydrocarbon foulants on the filter medium to regenerate the catalytic activity of the filter medium in the second portion of the treatment system.

21. The flue gas filter medium treatment system of claim 20, wherein the first portion of the treatment system is a first filter baghouse and the second portion of the treatment system is a second filter baghouse;wherein the incoming flue gas stream flows into an inlet of the first filter baghouse and the recirculated flue gas stream flows out of the first filter baghouse and into the second filter baghouse.

22. The flue gas filter medium treatment system of claim 20, wherein the first portion of the treatment system is a first portion of the filter medium and the second portion of the treatment system is a second portion of the filter medium;wherein the incoming flue gas stream flows through the first portion of the filter medium and the recirculated flue gas stream flows through the second portion of the filter medium.450385.0068023015W001 23. The flue gas filter medium treatment system of any one of claims 20-22, wherein the ABS foulant removal element introduces the fluid phase into the recirculated stream.

Images