Abstract:
An adjustable fuel nozzle assembly [ 1000 ] for spraying fuel into a recovery boiler [ 13 ] includes at least two fuel nozzle assemblies [ 1100, 1300 ]. An adjustment section [ 1500 ] adapted to adjust the relative orientation between the nozzle assemblies [ 1100, 1300 ] and hold them at the desired orientation relative to each other to create a desired spray pattern. The adjustment section [ 1500 ] also adapted to simultaneously aim several fuel nozzles at a target location, retaining their relative orientation between the nozzle assemblies [ 1100, 1300 ]. This allows the nozzle assemblies [ 1100, 1300 ] to spray fuel with a desired spray pattern to a desired location to properly control combustion of the recovery boiler [ 13 ], thereby increasing stability of combustion minimizing the creation of pollutants such as NOx gases.

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to recovery boilers and more specifically to an adjustable fuel nozzle system for recovery boilers. 
     BACKGROUND 
     Recovery boilers are used in various processes, such as manufacturing paper. Some of the organic products used in the process are flammable. Instead of discarding this waste material, it may be burned as a fuel for the boiler. The inorganic chemicals are collected at the bottom of the furnace and are discharged through dedicated openings in the lower furnace into a dissolving tank. 
       FIG. 1  shows a prior art recovery boiler system  3 . Initially a fuel, such as natural gas, is released from gas jets  9  of a burner  7  and ignited. They create combustion in combustion chamber  11 . 
     After the boiler system  3  heats up enough, then fuel is sprayed through fuel nozzles  13  into combustion chamber  11 . This fuel may be the organic waste product such as that referred to as “black liquor” created in the paper manufacturing process. Therefore, throughout this document, it is to be understood that fuels nozzles may also be referred to as “liquor guns”. 
     The heated flue gasses rise and heat pipes  5  filled with water. Any smelt from burning other materials will form in the bottom of boiler system  3  and run into a dissolving tank  17 . 
     The droplet size of the fuel sprayed from nozzles  13 , the spray pattern, the location where the fuel is introduced, the temperature of the combustion chamber  11  when the fuel was introduced and other factors have an effect on the amount of combustion produced, the subsequent temperature at different locations in the combustion chamber  11 , the stability of the combustion and the emissions produced. Therefore, the droplet size and spray distribution of the fuel is very important. Many of these factors are determined by the nozzle design. 
     The prior art discloses simple fuel nozzles such as the type described in U.S. Pat. No. 4,462,319 issued Jan. 31, 1984 to Larsen. This descried the use of fuel nozzles for recover boilers and relies on the use spray holes to define droplet size. Larsen does not address the positioning of fuel nozzles to regulate the combustion to meet some of the needs listed above. 
     Currently, there is a need for a fuel nozzle system that allows a user to adjust the location where fuel is sprayed and the distribution of fuel droplets sprayed to increase efficiency and reduce the amount of unwanted pollutant gases created, such as NOx. 
     SUMMARY 
     The present invention may be embodied as an adjustable fuel nozzle system 
     for providing fuel to a combustion chamber [ 111 ] of recovery boiler [ 103 ]. It includes an upper fuel nozzle assembly [ 1100 ], a lower fuel nozzle assembly [ 1300 ], and an adjustment section [ 1500 ]. 
     The upper and lower fuel nozzle assemblies [ 1100 ,  1300 ] each include an inlet line [ 1110 ] for receiving said fuel, an extension [ 1130 ] having a central conduit for directing said fuel from the inlet line [ 1110 ] through the extension [ 1130 ] having a first and second end, the first end being fluidically connected to the inlet line [ 1110 ], a nozzle outlet [ 1143 ] fluidically connected to the second end of the extension [ 1130 ] allowing said fuel to exit the extension [ 1130 ] as a jet of fuel. 
     The adjustment section [ 1500 ] is adapted to hold both the upper and lower fuel nozzle assemblies [ 1100 ,  1300 ] in a desired orientation relative to each other, and to permit adjustment of the orientation of both the upper and lower fuel nozzle assemblies [ 1100 ,  1300 ] keeping the same desired relative orientation between the nozzle assemblies [ 1100 ,  1300 ]. 
     The proper relative positioning of the fuel nozzle assemblies [ 1100 ,  1300 ] creates a more efficient spray pattern. By adjusting the spray pattern and adjusting the location where the fuel is sprayed may causes the recovery boiler [ 103 ] to become more stabile and create less pollutants. 
     OBJECTS OF THE INVENTION 
     It is an object of the present invention to reduce pollutant gasses, such as NOx emissions from chemical recover furnaces. 
     It is another object of the present invention to increase recover boiler firing and stability. 
     It is another object of the present invention to provide a system for more accurately creating and directing a fuel spray pattern. 
     It is another object of the present invention to provide a group of fuel nozzles that can be properly aimed together keeping their relative orientation. 
     It is another object of the present invention to provide a group of fuel nozzles that can be properly aimed together to impinge upon a desired target location. 
     It is another object of the present invention to provide a group of fuel nozzles in which the relative aim of at least one nozzle may be adjusted relative to the other nozzles to impinge upon a desired target location. 
     Other objects and advantages of the invention will become apparent from the drawings and specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the drawings, wherein like items are numbered alike in the various Figures: 
         FIG. 1  is a perspective view of a prior art recovery boiler system; 
         FIG. 2  is an elevational view of one embodiment of an adjustable fuel nozzle system according to the present invention; 
         FIG. 3  is an enlarged front elevational view of the adjustment section of the adjustable fuel nozzle system shown in  FIG. 2 ; 
         FIG. 4  is an enlarged side elevational view of the adjustment section of the adjustable fuel nozzle system according to the embodiment of the present invention shown in  FIGS. 2 and 3 ; and 
         FIG. 5  is a top plan view of the adjustment section of the adjustable fuel nozzle system of the present invention shown in  FIGS. 3 and 4 . 
         FIG. 6  is a top plan view of a portion of the upper fuel nozzle assembly. 
     
    
    
     DETAILED DESCRIPTION 
     As stated in the “Background” above, it is important to be able to adjust the spray pattern of the fuel nozzles. It is also important to position the spray nozzles to cause the boiler run within defined temperatures. The prior art does not address these problems; however, the present invention does. 
       FIG. 2  is an elevational view of one embodiment of an adjustable fuel nozzle system according to the present invention. The adjustable fuel nozzle system  1000  has an upper fuel nozzle assembly  1100  and a lower fuel nozzle assembly  1300 . Even though two are described here, the invention covers the use of multiple fuel nozzle assemblies. 
     Each of the fuel nozzle assemblies  1100 ,  1300  includes an inlet line  1110 ,  1310  for receiving fuel. The fuel is typically an organic manufacturing byproduct, such as ‘black liquor’ from a paper manufacturing process. 
     Extension  1130 ,  1330  are connected to inlet lines  1110 ,  1310  and pass the fuel to nozzles  1141 ,  1341 , respectively. 
     The fuel is sprayed out of nozzle opening  1143 ,  1343  into a combustion chamber  111  of boiler system  103  for combustion. If fuel is sprayed into the center of a hot flame, a larger amount of gasses such as NOx are created. However, if the fuel is only sprayed at the perimeter of the combustion chamber  111 , then it may liquefy and run into the smelt, wasting the fuel and causing additional problems in the smelt. 
     Therefore, it is best to be able to adjust the location as to where the fuel is being sprayed to control the combustion process. 
     In other uses, there is an optimum temperature to run the boiler system. Therefore, by altering the location of the fuel nozzles, one may control the boiler system keeping it within the proper range. 
     It is advantageous to break liquid fuel into small droplets. This causes more surface area and smoother, more complete combustion. One way to break liquid fuel into droplets is to use a spray head with small nozzle holes as described in U.S. Pat. No. 4,462,319 Larsen above. The smaller the hole, the smaller the droplet sizes created. This works well for pure fuel but blocks if solid particles are present in the fuel. 
     The present invention uses a nozzle with a nozzle opening, but causes the fuel jet exiting the nozzle opening to impinge upon a splash plate. This splash plate functions to break the liquid into small droplets, but is not as prone to blockage. 
     The present invention employs a plurality of fuel nozzles each having its own splash plate. The idea being that several smaller fuel nozzles would more efficiently spray the fuel into the combustion chamber and provide more uniform coverage. 
     Further, if the fuel nozzles are adjustable, the spray from one nozzle may be directed to supplement the spray pattern of another fuel nozzle, filling in areas that did not receive spray from the first nozzle. Once this adjustment of one nozzle relative to the second nozzle has been completed, it is desirable to keep them in the same relative position, but only to move them as a group, keeping the same relative orientation between them. The present invention employs such a relative adjustment and a group adjustment. 
     A relative hinge  1520  is used to adjust one fuel nozzle assembly  1100  relative to another fuel nozzle assembly  1300 , and then secure them to keep these in the same orientation relative to each other. 
     A group rotation hinge  1540  and an anchor hinge  1720  cause both fuel nozzle assemblies  1100 ,  1300  to be moved together around a group rotation pivot  1541  and an anchor pipe  1710 , respectively. This may be done while preserving the relative orientation between the fuel nozzle assemblies  1100 ,  1300 . 
       FIG. 3  is an enlarged front elevational view of the adjustment section of the adjustable fuel nozzle system shown in  FIG. 2 .  FIG. 4  is an enlarged side elevational view of the adjustment section  1500  of the adjustable fuel nozzle system  1000  according to the embodiment of the present invention shown in  FIGS. 2 and 3 .  FIG. 5  is a top plan view of the adjustment section of the adjustable fuel nozzle system of the present invention shown in  FIGS. 3 and 4 . 
     The present invention will be described below in connection with  FIGS. 3 ,  4  and  5 . 
     In this embodiment, an upper clamp  1510  clamps around and secures the upper extension  1130 , shown here in phantom. 
     A lower clamp  1530  surrounds and clamps lower extension  1330 , also shown in phantom. 
     Upper clamp  1510  and lower clamp  1530  both are attached to a relative hinge  1520  that pivots about relative hinge pivot  1521  in the direction of the arrow marked “B”. This allows upper extension to pivot about relative hinge pivot  1521  altering the relative orientation between upper extension  1130  and lower extension  1330 . Adjustment bolts  1523  are screwed in to the proper depth to hold the desired orientation. An additional nut may be screwed down on these to lock them at their position. 
     The difference in orientation adjusts the area sprayed by nozzle outlet  1143  relative to that sprayed by nozzle outlet  1343  to ‘fill in’ missed areas, or intensify spray in a desired area. 
     Going into greater detail, it can be seen that upper clamp  1510  has a clamp top  1511  and a clamp base  1513  that surround upper extension  1130 . A thumbscrew  1515  pulls clamp top  1511  to clamp base  1513  securing upper extension  1130  between them. 
     Similarly, lower clamp  1530  has a clamp top  1531  and a clamp base  1533  that surround lower extension  1330 . Thumbscrews  1535  pulls clamp top  1531  to clamp base  1533  securing upper extension  1130  between them. 
     An anchor pipe  1710  is fixed into a stationery structure and is used to hold the upper and lower fuel nozzle assemblies  1100 ,  1300  and the adjustment section  1500 . 
     Here two U-bolts  1723  attach anchor pipe to an anchor plate  1721 . Anchor plate  1721  is attached to a group rotation hinge  1540 . Group rotation hinge  1540  is also attached to clamp base  1531  of the lower clamp  1530 . 
     The U-bolts  1723  may be loosened to pivot the entire assembly (the anchor plate  1721 , the group rotation hinge  1540 , the lower clamp  1530 , the relative hinge  1520  the upper clamp  1510 , the lower fuel nozzle assembly  1300  and the upper fuel nozzle assembly  1100 ) around anchor pipe  1710  about its center  1715  in the direction of the arrows marked “A”. The U-bolts  1723  may then be tightened to keep them at that position. In effect, this is acting as a hinge or pivot. 
     The group rotation hinge  1541  allows the entire assembly above the anchor plate  1721  to pivot in the direction of the arrows marked “C”. The axis of rotation of “C” is approximately perpendicular to the axis of rotation of “A”. 
     Rotating according to the directions marked “A” or “C” would keep the same relative orientation between extensions  1130  and  1330 , and their respective nozzle outlets  1143  and  1343 , while moving both to aim at a different location. 
     This adjustability results in a system that more accurately adjusts spray patterns, keeps the same spray pattern as the aim of several nozzles are simultaneously adjusted to more accurately maintain the combustion of the boiler system. 
       FIG. 6  is a top plan view of a portion of the upper fuel nozzle assembly. Here nozzle  1141  and splash plate  1145  of the end of upper nozzle assembly  1100  are shown. The stream of fuel exiting the nozzle  1141  impact upon the splash plate  1145  and is sprayed as fuel droplets in the directions indicated by the arrows marked “D”. This embodiment of the splash plate  1145  is a planar, oval shape. It is attached directly within the stream of fuel flow and is wider than the nozzle  1141  and nozzle opening ( 1143  of  FIG. 2 ). Its width is selected such that any fuel leaving nozzle  1141  at a slight angle will still impact the splash plate  1145 . This is to insure that all fuel is broken into droplets, since fuel that is not broken into droplets causes incomplete combustion, increased pollutants and a loss of efficiency. 
     The nozzle design of the present invention results in more consistent temperatures, greater combustion stability and reduced creation of pollutants, such as NOx emissions. 
     Although the invention has been described and illustrated with respect to exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto, without parting from the spirit and scope of the present invention. Accordingly, other embodiments are within the scope of the following claims.