Abstract:
A lance for powder injection resulting in reduced agglomeration, including an outer tubular member having a first end, a second end, and an inner flowpath extending from the first end to the second end; an inner tubular member having a first end, a second end, and a, inner flowpath extending from the first end to the second end, the inner tubular member disposed within the inner flowpath of the outer tubular member for providing an annular space between the outer tubular member and the inner tubular member; and one or more orifices in the inner tubular member for providing a flowpath between the annular space and the inner flowpath of the inner tubular member. Additional lances, systems, and methods are also included.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 62/019,245, filed Jun. 30, 2014. The entirety of this aforementioned application is incorporated herein by reference. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    This invention relates, in general, to systems for reducing agglomeration of injected powder and, in particular, to systems, lances, nozzles, and methods for powder injection resulting in reduced agglomeration. 
       BACKGROUND OF THE INVENTION 
       [0003]    Without limiting the scope of the present invention, its background will be described in relation to systems for reducing agglomeration of injected powder and, in particular, to systems, lances, nozzles, and methods for powder injection resulting in reduced agglomeration, as an example. 
         [0004]    With the introduction of the first national standards for mercury pollution from power plants in 2011, many facilities will turn to activated carbon injection (ACI) to meet the regulatory requirements. ACI is a mature technology that is widely available and proven for achieving mercury removal to the required levels. ACI involves the pneumatic conveyance of a powdered activated carbon (PAC) or other type of powdered sorbent from a storage silo into the process gas of a power plant. Once introduced to the process gas, the sorbent adsorbs mercury. The sorbent and associated mercury is separated from the process gas by a particulate removal device resulting in lower concentrations of mercury in the gas. 
         [0005]    Most development work for this methodology has focused on controlling and modifying the PAC or other powdered sorbents to maximize their potential reaction with mercury. The result of these efforts has been to introduce oxidizing components to the sorbent as well as minimize particle size and pore diffusion resistance to accelerate the kinetic reaction to match system constraints. 
         [0006]    Commercial systems are readily available for powder flow transport and delivery and have been adapted for ACI systems. These systems include a powder storage vessel with some means of fluidization, a flow path to a feed hopper that uses various combinations of valves and screws to convey powder to an eductor, and transport lines that convey transport air and powder to injection lances, as further discussed below with reference to FIGS.  1 A 1 - 1 C 2 . The entire system must operate continuously without plugging or clogging to introduce powder to the flue gas. The delivery of the powder from the injection lances is critical to the resulting reactions in the process gas. ACI installations at existing power plants are limited by the given process framework and therefore locations where the ACI system can be installed and (therefore where the powder can be injected) is limited. 
         [0007]    This often constrains the available contact time for PAC to adsorb mercury (as defined by the time the PAC enters the gas environment in the duct system to the time it is removed by the particulate control device). In addition to this constraint, process gases are generally high volume flows thereby having low concentrations of contaminants, especially in the case for mercury. With limited time and low concentration of the target contaminant to be removed, it is critical to maximize the dispersion (and therefore reactive surface area) and the particle distribution of the sorbent in the process gas to in turn maximize the contaminant removal potential. 
         [0008]    As used herein, “dispersion” will be referred to as the degree of agglomeration, or how well the actual average particle size matches that of the primary particle size. Highly dispersed powders are those in which there is little to no agglomeration and the actual average particle size is equivalent to the primary particle size. Low dispersion would conversely mean that there is a large degree of agglomeration and the actual average particle size is much larger than that of the primary particle size. Distribution of the particles herein will refer to the degree that particles are separated from each other and their location in the process gas. High dispersion conditions will have particles that are well separated and fill the process gas volume thereby having good interaction with the process gas. Low dispersion conditions may have streamlining where particles are in closer proximity to each other and occupy only a portion of the available volume. 
         [0009]    Fine powders have an inherent cohesive tendency and form agglomerates. Therefore, when agglomerates form, the average particle size of the powder being introduced into the process gas will have a larger size than the primary particle size originally produced. Larger particle size leads to less available reactive external surface area and less particle gas interaction. This works against high levels of contaminant removal from process gas. This is especially so in the case of mercury removal from flue gas where mercury removal is mass transfer limited. Despite the efforts to improve the PAC reactivity, if its surface area is not readily accessible, mercury removal will be limited. 
         [0010]    This theory was demonstrated using an in-line particle size measurement tool that monitored particle size in the flue gas with increasing injection rates. The tendency of PAC to agglomerate increased with increased particle feed rate. As PAC agglomerates, much of its surface area gets blocked off and is no longer exposed directly to the process gas. These measurements explain the phenomena of the mercury removal performance plateau exhibited in many ACI systems despite increasing injection rates. Therefore, if agglomeration can be eliminated and particles reduced back to their primary particle size, the linear trend of increasing mercury removal with increasing injection rates could be maintained. 
         [0011]    Several styles of lances are commonplace in ACI systems currently employed. Referring to FIGS.  1 A 1 - 1 C 2 , several prior art lances are discussed. The main style of lance employed is a lance  10  having a tubular body  12  and one end  14  that connects with a supply of pneumatically powered powder, such as ACI (FIGS.  1 A 1 - 1 A 2 ). Lance  10  may have a second end  16  that is substantially square or flat and having an opening  18  where ACI flows outward. Another configuration includes a lance  20  having a tubular body  22  and one end  24  that connects with a powdered ACI (FIGS.  1 B 1 - 1 B 2 ). Lance  20  may also include a second end  26  that may be angled and having an opening  28  where ACI flows outward. 
         [0012]    While these lance designs have low tendency to plug, they also do a poor job of dispersing and distributing the powder particles. Increasing the number of lances in a cross section and staggering their injection lengths can improve this distribution. More lances, however, comes with the drawback of larger pressure drop in the lines which can lead to sedimentation and clogging or necessitate a larger flow or pressure air supply. Another commonly applied design tries to improve particle distribution by using an injection lance  30  having a tubular body  32  and one end  34  that connects with a powdered ACI (FIGS.  1 C 1 - 1 C 2 ). Lance  30  may also include several holes  34  along the vertical length of body  32 . Tubular body may have a closed end  36 . While this design allows for better distribution of powder across the duct cross-section and less lances, it is prone to clogging. These traditional lances, without a mechanism to de-agglomerate powder particles, lack the ability to finely disperse the powder particles which limits the upper level of possible contaminant removal despite how well of a distribution can be achieved. 
         [0013]    In another method in previous use, a system to re-mill PAC just prior to injection into the flue gas may be used. This would remove agglomerates formed during storage and transportation. However, during conveyance and injection in the ACI system, particles will have a chance to re-form agglomerates thereby limiting the potential of the powder to react and capture mercury. In addition, if the applied lance design used in conjunction with the milling system does not distribute these particles well in the flue gas cross section, mercury removal will again be limited. 
         [0014]    Another method to introduce additives to contaminant-containing gases includes compressing a gas, contacting the additive with the compressed gas, mixing the additives and gas, and delivering the mixture to contaminant-containing gas stream delivery system of a manifold and many conduits, or lances. While this system claims to improve distribution of the additives, it does not include methods to improve particle distribution. 
         [0015]    Another method for ACI known to those skilled in the art is a typical pneumatic injection system that injects particles into a gas duct that contains a static mixer. The design is intended to improve powder distribution in the duct itself and requires little to no maintenance. While this method improves on particle distribution, again, there are no means to disperse the particles to their primary particle size and increase the available reactive surface area. Additionally, integrating the static mixer requires replacing a portion of the duct while the power plant is not operating incurring high cost and inconvenience. 
         [0016]    Another system is an integrated mercury control system that includes a sorbent injection subsystem wherein the system adapted to disperse sorbent particles within the flue gas stream at a defined rate for the sorbent particles to adsorb gaseous pollutants. As part of this subsystem, injection lances were comprised of various conduits. These conduits consist of a first end where the sorbent material is fed into and the product travels down the length of the conduit to a second end where the sorbent particles are released. The varying vertical lengths allow for greater distribution of the particles. While the disclosure claims that the amount of clumping of particles is reduced by the straight flow, low-pressure conduits with no curves or angles, there are no means to disperse already formed clumps or agglomerates. 
       SUMMARY OF THE INVENTION 
       [0017]    This present invention disclosed herein is directed to dispersing the PAC by creating an environment that breaks particle agglomerates to disperse the particles to their primary particle size rather than the larger agglomerated clusters thus increasing distribution of the particles in the flue gas duct. Creating this environment promotes both dispersion in the flue gas cross-section and increased available external surface area for reaction that lead to improved contaminant removal. With limited contact time for these reactions to occur, both variables are critical for effective contaminant removal. 
         [0018]    Advanced lance systems of the present invention include modified lance designs that focus on a nozzle geometry in which flow profiles induce the breaking of agglomerates to reduce the average particle size down closer to the primary particle sizes of powder PAC. The breakup of agglomerated powder is influenced by four mechanisms. First, local accelerations induce forces on agglomerates that break the agglomerates apart. Second, agglomerates break apart when they interact with other agglomerates in the system. Third, agglomerates break when they interact with a boundary (physical, static, or dynamic). Fourth, agglomerates break when subjected to gas pressure acting within the agglomerate, which induces sufficient stress in the agglomerate to overcome attractive forces between particles. These principles were applied to develop the disclosed lance designs. Some designs are given below as examples but are not intended to be all-inclusive. These designs may be referred to as lances, nozzles, and/or agglomeration reduction systems. 
         [0019]    In one embodiment, the present invention may be directed to a lance for powder injection resulting in reduced agglomeration, including an outer tubular member having a first end, a second end, and an inner flowpath extending from the first end to the second end; an inner tubular member having a first end, a second end, and an inner flowpath extending from the first end to the second end, the inner tubular member disposed within the inner flowpath of the outer tubular member for providing an annular space between the outer tubular member and the inner tubular member; and one or more orifices in the inner tubular member for providing a flowpath between the annular space and the inner flowpath of the inner tubular member. 
         [0020]    In one aspect, the annular space may be sealed at the first end of the inner tubular member and outer tubular member. In another aspect, the first end of the inner tubular member may include one or more of a nozzle, lance end, and outlet. In yet another aspect, the one or more orifices are disposed through the longitudinal axis of the inner tubular member. Also, the one or more orifices may be disposed through the inner tubular member in one or more different radial positions about the circumference of the inner tubular member. Additionally, the inner tubular member and the outer tubular member are substantially coaxial. Further, the one or more orifices may be angled for providing a tangential directional flowpath between the annular space and the inner flowpath of the inner tubular member. 
         [0021]    In another embodiment, the present invention may be directed to a nozzle for powder injection resulting in reduced agglomeration, including a tubular member having a sealed first end, a second end, and an inner flowpath extending from the sealed first end to the second end, the tubular member having one or more orifices disposed therethrough; and one or more flow agitation baffles disposed a distance about the outer surface of tubular member substantially proximal to the one or more orifices. 
         [0022]    In one aspect, the nozzle may include one or more supports for supporting the one or more flow agitation baffles the distance about the outer surface of the tubular member. In another aspect, each of the one or more flow agitation baffles may create a turbulent flow profile to at least two of the one or more orifices. In yet another aspect, the at least one or more flow agitation baffles may be disposed linearly along the longitudinal axis of the outer surface of the tubular member. 
         [0023]    Also, the at least one or more flow agitation baffles may be disposed in different positions about the radius of the outer surface of the tubular member. Additionally, the one or more flow agitation baffles may have a profile selected from the group consisting polygonal forms, symmetrical forms, and asymmetrical forms. Further, one of the one or more supports may be disposed between the one or more orifices. In still yet another aspect, one of the form and shape of the flow agitation baffles may be selected from the group consisting of planar, curved, and curvilinear. 
         [0024]    In yet another embodiment, the present invention may be directed to a nozzle for powder injection resulting in reduced agglomeration, including a tubular member having a sealed first end, a second end, and an inner flowpath extending from the first sealed end to the second end, the tubular member having an orifice disposed therethrough proximal to the sealed first end; and a dispersion plate disposed a distance about the outer surface of tubular member substantially proximal to the orifice. In one aspect, the nozzle may include a support for supporting the dispersion plate a distance about the outer surface of the tubular member. Also, the dispersion plate may create a turbulent flow profile to the orifice. 
         [0025]    In yet another aspect, the dispersion plate has a profile selected from the group consisting polygonal forms, symmetrical forms, and asymmetrical forms. In still yet another aspect, one of the form and shape of the dispersion plate may be selected from the group consisting of planar, curved, and curvilinear. 
         [0026]    In still yet another embodiment, the present invention may be directed to a powdered activated carbon injection unit, including a source of the process gas; and a lance in contact with the process gas having an outer tubular member having a first end, a second end, and an inner flowpath extending from the first end to the second end; an inner tubular member having a first end, a second end, and an inner flowpath extending from the first end to the second end, the inner tubular member disposed within the inner flowpath of the outer tubular member for providing an annular space between the outer tubular member and the inner tubular member; and one or more orifices in the inner tubular member for providing a flowpath between the annular space and the inner flowpath of the inner tubular member. 
         [0027]    In one aspect, the annular space may be sealed at the first end of the inner tubular member and outer tubular member. In another aspect, the first end of the inner tubular member may include one or more of a nozzle, lance end, and outlet. 
         [0028]    In still yet another embodiment, the present invention may be directed to a powdered activated carbon injection unit, including a source of the process gas; and a nozzle in contact with the process gas having a tubular member having a sealed first end, a second end, and an inner flowpath extending from the sealed first end to the second end, the tubular member having one or more orifices disposed therethrough; and one or more flow agitation baffles disposed a distance about the outer surface of tubular member substantially proximal to the one or more orifices. 
         [0029]    In one aspect, the first end of the inner tubular member may include one or more of a nozzle, lance end, and outlet. In another aspect, the powdered activated carbon injection unit may include one or more supports for supporting the one or more flow agitation baffles the distance about the outer surface of the tubular member. In yet another aspect, each of the one or more flow agitation baffles may create a turbulent flow profile to at least two of the one or more orifices. 
         [0030]    In another embodiment, the present invention may include a method for powder injection resulting in reduced agglomeration, including providing a process gas; and providing a lance having a turbulent flow device for injecting dispersed powdered activated carbon for contacting the process gas. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]    For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which: 
           [0032]    FIG.  1 A 1  is a side view of a prior art injection lance; 
           [0033]    FIG.  1 A 2  is an end view of the prior art injection lance of FIG.  1 A 1 ; 
           [0034]    FIG.  1 B 1  is a side view of a prior art injection lance; 
           [0035]    FIG.  1 B 2  is an end view of the prior art injection lance of FIG.  1 B 1 ; 
           [0036]    FIG.  1 C 1  is a side view of a prior art injection lance; 
           [0037]    FIG.  1 C 2  is an end view of the prior art injection lance of FIG.  1 C 1 ; 
           [0038]      FIG. 2  is a block diagram of a pneumatic system having lances and/or nozzles for injecting powdered activated carbon into a gas flow according to an embodiment; 
           [0039]      FIG. 3  is a block diagram of a system having injection lances and/or nozzles for injecting powdered activated carbon into process gas according to an embodiment; 
           [0040]      FIG. 4  is a cross section view of a nozzle according to an embodiment; 
           [0041]      FIG. 5  is a front view of the inner nozzle of the nozzle of  FIG. 4  according to an embodiment; 
           [0042]      FIG. 6A  is a front view of a nozzle having baffles according to an embodiment; 
           [0043]      FIG. 6B  is a side view of the nozzle of  FIG. 6A  according to an embodiment; 
           [0044]      FIG. 7A  is a front view of a nozzle having a baffle according to an embodiment; 
           [0045]      FIG. 7B  is a side view of the nozzle of  FIG. 7A  according to an embodiment; and 
           [0046]      FIG. 8  is a flowchart of a process for controlling multiple pollutants from process gas according to an embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0047]    While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not limit the scope of the present invention. 
         [0048]    The various embodiments of the present invention generally relate to a system, lances, nozzles, and/or methods for introducing a powder, such as a powdered activated carbon (“PAC”) and/or activated carbon, into a gas stream with a high degree of dispersion and distribution. In the following description, the term PAC may be used primarily, but the description also applies to activated carbon, and the like as would be commonly known to those skilled in the art. The gas stream and/or process gas stream may originate from many industrial facilities such as a power plant, cement plant, waste incinerator, or other facilities that will occur to one skilled in the art. Such gas streams contain many contaminants that are desirable to control and/or decrease in concentration for protection of health and the environment. 
         [0049]    Referring initially to  FIG. 2 , an embodiment of a system for injecting PAC into a process gas for controlling or reducing pollutants in a gas stream is schematically illustrated and generally designated  100 . In one embodiment, system  100  may include an activated carbon injection (“ACI”) system. System  100  may include a PAC storage vessel, such as activated carbon silo  102 , where PAC  104  may be stored for use in system  100 . Activated carbon silo  102  may be any type of storage vessel such that it is capable of containing a supply and/or feedstock of PAC for supplying the PAC to other units and the like of system  100 . Some additional exemplary activated carbon silos  102  may include supersacs, silos, storage vessels, and the like. 
         [0050]    In one embodiment, system  100  may include one or more fluidizing nozzles  106  that may assist in providing PAC  104  in a fluidized form, such that it may be transported in a substantially fluid form downstream in system  100 . Additionally, system  100  may include one or more control valves  108  that may be disposed and/or located substantially proximal to the exit or outlet of PAC  104  and/or fluidizing nozzles  106  for controlling the flow of PAC  104  from activated carbon silo  102  to system  100 . The feed of PAC  104  can also be controlled by a series of additional control valves  108 , movable barriers, etc. To assist the process of fluidizing PAC  104  for exiting activated carbon silo  102 , fluidization assistance may be applied in the form of physical agitation or the use of fluidizing nozzles  106 . In addition, system  100  may include other types of control valves, such as manual valves (not shown), and the like as would be known to those skilled in the art. 
         [0051]    System  100  may further include a movement joint or expansion joint  110  located or disposed downstream of control valves  108 . Expansion joint  110  may provide for absorption of relational movements between activated carbon silo  102  and other downstream units, controls, devices and the like. Some exemplary relational movements may be heat induced, vibratory, and the like. In one embodiment, expansion joint  110  may be located between control valves  108  and a feeder hopper  112 . System  100  may also include a valve, such as a rotary valve  114  that may be located or disposed between feeder hopper  112  and one or more load cells  116 . System  100  may also include a screw feeder  118  disposed or located downstream of the load cells  116 . In another embodiment, PAC  104  may be controlled or metered with any typical device known to those skilled in the art. 
         [0052]    System  100  may further include a flow eductor  120  that is located downstream of  118 . System  100  may also include a blower  122  for providing an air flow post flow eductor  120 . At this point, PAC  104  may be introduced to the pneumatic conveying gas produced by blower  122  through flow eductor  120  that combines PAC  104  producing a fluid stream for flowing through a transport line  124  to a desired injection location, as further discussed below. 
         [0053]    In one embodiment, rotary valve  114 , screw feeder  118 , load cells  116 , blower  122 , and flow eductor  120  may modulate and control the pressure and flow of PAC  104  along a transport line  124  to an injection manifold  128  having one or more injection lances  130 . Transport line  124  may include bends, such as 90 degree bends  126  or other impediments. Injection manifold  128  and injection lances  130  may be located or disposed in a process line, vessel, transport line, housing, container, etc. (“process line  132 ”) containing a source of gas  134 , such as a process gas for controlling or reducing pollutants, and the like. 
         [0054]    Referring now to  FIG. 3 , another embodiment of a system for injecting PAC into a process gas for controlling or reducing pollutants in a gas stream is schematically illustrated and generally designated  200 . System  200  may be a coal-fired electric power generation plant, in one embodiment. System  200  may include a boiler  202 , such as for a coal-fired power plant. Although the example described herein applies to coal-fired power plants, the process gas or flue gas to be treated may originate from many industrial facilities such as a power plant, cement plant, waste incinerator, or other facilities that will occur to one skilled in the art. 
         [0055]    Such gas streams contain many contaminants and/or pollutants that are desirable to control and/or decrease in concentration for protection of health and the environment. Nevertheless, system  200  is being described for removing, controlling, and/or reducing pollutants from a coal-fired power plant gas stream using one or more of the lances discussed herein. Boiler  202  may be a coal-fired boiler that burns or combusts coal to heat water into superheated steam for driving steam turbines that produce electricity. These types of power plants are common throughout the U.S. and elsewhere. Boiler  202  may further include an economizer  204 , in one embodiment. Economizer  204  may be used to recover heat produced from boiler  202 . 
         [0056]    The flue gas or process gas  205  exiting boiler  202  and/or  204  may then be flowed, transported, ducted, piped, etc. via one or more process lines  206  to a selective catalytic reduction unit  208  for the removal of nitrogen containing compounds, in one embodiment. Typically, selective catalytic reduction unit  208  may convert NO x  compounds to diatomic nitrogen (N 2 ) and water (H 2 O) using a catalyst and a gaseous reductant, such as an ammonia containing compound. 
         [0057]    Process gas  205  may then be flowed, transported, ducted, piped, etc. to a heat exchanger, pre-heater, and/or air heater  210  where heat is transferred from the flue gas to a feed of air to be fed back into boiler  202 . Process gas  205  may then be transferred via process line  206  to an electrostatic precipitator  212  for removal of PAC  207 , which has been injected into system  200  at some point preferably upstream of electrostatic precipitator  212 . 
         [0058]    PAC  207  may be injected anywhere along process line  206  from boiler  202  to electrostatic precipitator  212 , including boiler  202 , economizer  204 , selective catalytic reduction unit  208 , air heater  210 , and/or electrostatic precipitator  212 . 
         [0059]    After being treated in  212 , the treated flue gas may then be sent to a flue gas desulfurization unit  214  via process line  206  for removal of sulfur compounds, in one embodiment. After being treated in flue gas desulfurization unit  214 , the treated flue gas may then be sent to a stack  216  for emission into the environment. 
         [0060]    Turning now to  FIG. 4 , another embodiment of a lance or nozzle for injecting PAC into a process gas for controlling or reducing pollutants in a gas stream is schematically illustrated and generally designated  400 . Nozzle  400  may include an outer tubular member  402  having an end  404  in communication with a source of a gas  406 , such as pressurized air in one example. Located and/or disposed within the inner cavity or pathway of outer tubular member  402 , is an inner tubular member  408  creating a substantially annular space  410  located and/or disposed between outer tubular member  402  and inner tubular member  408 . 
         [0061]    Nozzle  400  further includes an end  412  that may be located and/or disposed in a source of process gas, such as process gas  205  and/or gas  134 . Additionally, nozzle  400  includes a lance end, nozzle end, and/or outlet  413  that PAC  420  exits out of nozzle  400  where it contacts a process gas, for example. Preferably, end  412  may have a sealed end  414  between outer tubular member  402  and inner tubular member  408 , for blocking the flow of gas  406  through the end  412  of annular space  410 , in one example. Sealed end  414  may be any common seal, welds, structures, caps, and the like that blocks the flow of gas  406  out end  412  through annular space  410 , as would be commonly known to those skilled in the art. 
         [0062]    As discussed above, annular space  410  provides a pathway or flowpath for a source of gas  406 , such as pressurized gas and/or air. In addition, inner tubular member  408  includes a pathway and/or flowpath  416  for a source of PAC to flow through from end  404  where it exits at end  412  into process gas  205  and/or gas  134 , in one embodiment. In one aspect, flowpath  416  is the central via or cavity of inner tubular member  408 . In one embodiment, outer tubular member  402  and inner tubular member  408  may be disposed relationally in a co-axial manner. In another embodiment, outer tubular member  402  and inner tubular member  408  may be disposed relationally slightly off-center with respect to their respective longitudinal center axis. Further, the shapes and/or forms of outer tubular member  402  and inner tubular member  408  may have any desired cross-sectional shape, such as circular, triangular, square, polygonal, symmetrical, asymmetrical, and the like. In one embodiment, outer tubular member  402  and inner tubular member  408  are preferably pipes or tubes having substantially hollow inner flowpaths or cavities. 
         [0063]    Nozzle  400  may further include one or more orifices  418 , such as openings, apertures, and the like disposed therethrough the wall of inner tubular member  408  for providing a flowpath for gas  406  to flow from annular space  410  through orifices  418  into flowpath  416 . Orifices  418  may be any form or shape such that they provide a desired flow of gas  406  from annular space  410  to flowpath  416 . In one embodiment, one or more orifices  418  may be aligned or staggered through inner tubular member  408 . 
         [0064]    As shown in  FIG. 4 , gas  406  flows along annular space  410  and then through orifices  418  to enter flowpath  416 . In one embodiment, gas  406  flows through annular space  410  and then through orifices  418  in a radially inward direction into flowpath  416  near end  412 . In one embodiment, PAC  420  is pneumatically conveyed through flowpath  416  as gas  406  is sent through annular space  410  and then orifices  418  into flowpath  416 . In another embodiment, PAC  420  may be conveyed through flowpath  416  with any type of pressurized carrier gas as would be known to those skilled in the art. 
         [0065]    PAC  420  experiences significantly more local acceleration effects and particle collisions at the intersections of the outlet of orifices  418  and flowpath  416  due to the annular gas cross-flow, thereby encouraging the dispersion of particles of PAC  420  to their primary particle size by increasing stress on the agglomerates. The cross-flow also induces more particle-to-particle collisions that will also further decrease the particle size of PAC  420 . The degree of dispersion of PAC  420  can be controlled by controlling the ratio of the flow of gas  406  to the flow of gas conveying the PAC  420  and may be dependent on the dimensions of nozzle  400  and powder diameter. Due to the added turbulence and smaller particle sizes, the powder stream leaving nozzle  400  will also disperse to a larger area than the lances typically applied. 
         [0066]    Turning now to  FIG. 5 , another embodiment of an inner tubular member is schematically illustrated and generally designated  500 . As discussed herein, inner tubular member may have any number of orifices therethough, and they may be located or disposed in any desired manner through inner tubular member. In one embodiment, inner tubular member  500  may have orifices  418  located or disposed along the length of inner tubular member  500 , such as along one or more positions around the radius of inner tubular member  500 . As shown, orifices  418  may have one or more orifices  418  disposed or located along the length of inner tubular member  500  and one or more orifices  418  disposed or located in a different position or side, such as shown in  FIG. 5 . 
         [0067]    Referring now to  FIGS. 6A-6B , another embodiment of a lance or nozzle for injecting PAC into a process gas for controlling or reducing pollutants in a gas stream is schematically illustrated and generally designated  600 . Nozzle  600  may include tubular member  602  having an end  604  in communication with a source of pneumatically conveyed PAC, source of pressurized PAC, and the like. Additionally, nozzle  600  may have a sealed end  606  sealing the end of tubular member  602 . Tubular member  602  of nozzle  600  includes a pathway and/or flowpath  608  for a source of PAC  610  to flow from end  604  through flowpath  608 . In one aspect, flowpath  608  is the central via or cavity of tubular member  602 . 
         [0068]    Further, the shapes and/or forms of tubular member  602  may have any desired cross-sectional shape, such as circular, triangular, square, polygonal, symmetrical, asymmetrical, and the like. In one embodiment, tubular member  602  is preferably pipes or tubes having substantially hollow inner flowpaths or cavities. 
         [0069]    In one embodiment, nozzle  600  may include one or more flow agitation baffles  612  may be disposed about the outside or outer surface of tubular member  602  for creating a dynamic boundary to induce a turbulent flow profile. Additionally, nozzle  600  may include one or more orifices  614 , such as openings, apertures, and the like disposed therethrough the wall of tubular member  602  for providing a flowpath for pressurized and/or pneumatically powered PAC  610  to flow from flowpath  608  through orifices  614  into the turbulent flowpaths created by flow agitation baffles  612 . 
         [0070]    In one embodiment, flow agitation baffles  612  may be structures having a front profile  618  of a desired form or shape, such as shown in  FIG. 6A  for producing turbulent flowpaths. As shown, profile  618  is substantially like a triangle with an inverted triangle connected together, but profile  618  may be any shape or form as desired to produce a desired turbulent flowpath. In one aspect, flow agitation baffles  612  may be of a depth such that it can be supported by a support  616  away from the outside or outer wall surface of tubular member  602 . 
         [0071]    Nozzle  600  may include any number of flow agitation baffles  612  and they may be disposed about the outside or outer wall of tubular member  602  in any pattern desired. For example, flow agitation baffles  612  are shown positioned in a substantially linear orientation along the centerline of tubular member  602 . They may also be positioned in a staggered orientation if desired. Further, they may be positioned about tubular member  602  where one or more are in a different position with respect to outer radius of tubular member  602 . Additionally, any number of them may be located or disposed about the length and/or radius of tubular member  602 . Flow agitation baffles  612  may be made out of any types of materials such that they can operate in the environment where PAC  610  may contact a process gas, for example. 
         [0072]    Nozzle  600  may include any number of orifices  614  and they may be located or disposed through tubular member  602 . They may be located or disposed along the length and/or radius of tubular member  602 , in one aspect. Preferably, they are located or disposed substantially near or proximal to the one or more flow agitation baffles  612  for increasing turbulent flow of PAC  610 . In one embodiment, one orifice  614  may be disposed or located on one side of support  616  and another on the other side of support  616  proximal to flow agitation baffles  612 . 
         [0073]    Support  616  may be any type of support such that it can support flow agitation baffles  612  a desired distance from the outside or outer wall surface of tubular member  602 , as best shown in  FIG. 6B . Support  616  may be connected at any point on flow agitation baffles  612  and tubular member  602 , in one aspect. 
         [0074]    Turning now to  FIGS. 7A-7B , another embodiment of a lance or nozzle for injecting PAC into a process gas for controlling or reducing pollutants in a gas stream is schematically illustrated and generally designated  700 . Nozzle  700  may include tubular member  702  having an end  704  in communication with a source of pneumatically conveyed PAC, source of pressurized PAC, and the like. Additionally, nozzle  700  may have a sealed end  706  sealing the end of tubular member  702 . Tubular member  702  of nozzle  700  includes a pathway and/or flowpath  708  for a source of PAC  710  to flow from end  704  through flowpath  708 . In one aspect, flowpath  708  is the central via or cavity of tubular member  702 . 
         [0075]    Further, the shapes and/or forms of tubular member  702  may have any desired cross-sectional shape, such as circular, triangular, square, polygonal, symmetrical, asymmetrical, and the like. In one embodiment, tubular member  702  is preferably pipes or tubes having substantially hollow inner flowpaths or cavities. 
         [0076]    In one embodiment, nozzle  700  may include one or more dispersion plates  712  may be disposed about the outside or outer surface of tubular member  702  for creating a dynamic boundary to induce a turbulent flow profile. Additionally, nozzle  700  may include one or more orifices  714 , such as openings, apertures, and the like disposed therethrough the wall of tubular member  702  for providing a flowpath for pressurized and/or pneumatically powered PAC  710  to flow from flowpath  708  through orifices  714  into the turbulent flowpaths created by dispersion plate  712 . 
         [0077]    In this embodiment, nozzle  700  may have one orifice  714  that may have a diameter up to the diameter of tubular member  702 . 
         [0078]    In one embodiment, dispersion plate  712  may be structures having a front profile  718  of a desired form or shape, such as shown in  FIG. 7A  for producing turbulent flowpaths. As shown, profile  718  is substantially circular, but profile  718  may be any shape or form as desired to produce a desired turbulent flowpath. In one aspect, dispersion plate  712  may be of a depth such that it can be supported by a support  716  away from the outside or outer wall surface of tubular member  702 . 
         [0079]    Support  716  may be any type of support such that it can support dispersion plate  712  a desired distance from the outside or outer wall surface of tubular member  702 , as best shown in  FIG. 7B . Support  716  may be connected at any point on dispersion plate  712  and tubular member  702 , in one aspect. In one embodiment, support  716  may be located or disposed about end  706  to support dispersion plate  712 . In one aspect, dispersion plate  712  creates a physical boundary to increase particle-to-particle and particle-to-boundary collisions thereby encouraging dispersion to the primary particle size and also promoting dispersion into the contaminated gas stream. 
         [0080]    Turning now to  FIG. 8 , a method for controlling or removing pollutants or contaminants in flue gas or process gas is schematically illustrated and generally designated  800 . In step  802 , process or flue gas may be transferred to a pre-heater for heat transfer to an air source to be fed back into a particular unit, such as boiler  202 . In step  804 , the process or flue gas is transferred to an economizer prior to transferring it to a SCR, such as selective catalytic reduction unit  208 . This step may include contacting the process or flue gas with PAC for controlling the pollutants or contaminants. In step  806 , the process or flue gas may be transferred air heater and then to an electrostatic precipitator  212 . In step  808 , the PAC may be recovered or separated from the process or flue gas in the electrostatic precipitator  212 . Step  810  may include transferring the treated process or flue gas to stack  216  for emission into the environment. 
         [0081]    The following example is intended to provide an illustration of certain aspects, embodiments, and configurations of the disclosure without limiting the disclosure. 
         [0082]    An ACI test for mercury removal was conducted at a coal-fired power plant burning high sulfur bituminous coal employing an air heater (AH), electrostatic precipitator (ESP), and wet flue-gas desulfurization unit for pollution control. Ports for ACI lances were installed between the AH and ESP. This location afforded a very short residence time for PAC to remove mercury from the flue gas. 
         [0083]    Several lances were installed in the ports and tested with a PAC injection rate of 7 lb/MMacf (million actual cubic feet). Million actual cubic feet Mercury was monitored just downstream of the ESP and percent total mercury removal was calculated by comparing non-injection and injection periods. The results of the test are shown in Table 1. Using the standard lance design  20  typical of the prior art, a straight metal tube  20  with a single slanted open end  26  (FIG.  1 B 1 - 1 B 2 ), nearly 20% mercury removal was reached at the constant injection rate. Mercury removal dropped slightly when using another prior art lance design  30  with multiple orifices  34  along the pipe length  32  (FIG.  1 C 1 - 1 C 2 ). However, once lances of the present invention were installed, mercury removal sharply increased. Nozzle or lance  600  ( FIG. 6A-6B ) increased mercury removal by nearly 90% more than the standard lance  20 . Nozzle or lance  700  ( FIGS. 7A-7B ) increased mercury removal by over 140% more than the prior art standard lance  20 . Installing nozzles or lances  600  and/or  700  would have a small capital expense and result in a dramatic decrease in PAC usage and thereby operating costs. 
         [0000]    
       
         
               
             
               
               
             
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Summary of Experimental Results 
               
             
          
           
               
                   
                 Percent Total Mercury 
               
               
                 Nozzle or Lance 
                 Removal 
               
               
                   
               
             
          
           
               
                 Standard Lance 20 of Prior Art (FIGS. 1B1-1B2) 
                 19.5 
               
               
                 Multi-Hole Lance 30 of the Prior Art 
                 13.4 
               
               
                 (FIGS. 1C1-1C2) 
               
               
                 Lance or Nozzle 600 (FIGS. 6A-6B) 
                 31.2 
               
               
                 Lance or Nozzle 700 (FIGS. 7A-7B) 
                 47.4 
               
               
                   
               
             
          
         
       
     
         [0084]    While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments.