Burner for combustion of heavy fuel oils

Abstract

A combustion chamber for combustion of heavy fuel oil, enclosed by a wall extending longitudinally toward a gas outlet in a tapered manner, defining an elongated chamber. The chamber includes a pre-combustion region operative for mixing the fuel oil with air, a peak-combustion region, and a secondary-combustion region. An upstream group of confinement apertures, and a downstream group of confinement apertures, circumferentially disposed around the perimeter of the wall, allow pressurized air flow into the combustion chamber to form an air curtain barrier between the pre-combustion region and peak-combustion region and an air curtain barrier between the peak-combustion region and secondary-combustion region during the combustion of the air-fuel mixture, such that the air-fuel mixture is temporarily detained and confined within the peak-combustion region, prolonging the combustion within the peak-combustion region. A corresponding method for combustion of heavy fuel oil is also provided.

1 . A combustion chamber for combustion of heavy fuel oil, the combustion chamber enclosed by a wall extending longitudinally toward a gas outlet in a tapered manner, defining an elongated chamber having a longitudinal axis normal to said gas outlet, said chamber comprising:
 a pre-combustion region;   a peak-combustion region;   and a secondary-combustion region,   wherein said pre-combustion region is operative for mixing said fuel oil with air,   said chamber further comprising a plurality of apertures, operative for allowing air flow into said chamber, said apertures comprising:   an upstream group of confinement apertures, circumferentially disposed around the perimeter of said wall between said pre-combustion region and said peak-combustion region; and   a downstream group of confinement apertures, circumferentially disposed around the perimeter of said wall between said peak-combustion region and said secondary-combustion region,   wherein said groups of confinement apertures allow pressurized air flow into said combustion chamber, forming an air curtain barrier between said pre-combustion region and said peak-combustion region and forming an air curtain barrier between said peak-combustion region and said secondary-combustion region during the combustion of said air-fuel mixture, such that said air-fuel mixture is temporarily detained and confined within said peak-combustion region, prolonging said combustion within said peak-combustion region.   
     
     
         2 . The combustion chamber of  claim 1 , further comprising:
 a fuel atomizer nozzle, operative for injecting a spray of fuel droplets into said pre-combustion region;   a gas inlet, operative for injecting ignition gas into said pre-combustion region; and   an igniter, operative for igniting said ignition gas to initiate combustion of an air-fuel mixture within said pre-combustion region.   
     
     
         3 . The combustion chamber of  claim 1 , wherein said plurality of apertures further comprises a group of air mixture apertures, circumferentially disposed around the perimeter of said pre-combustion region upstream from said upstream group of confinement apertures, said air mixture apertures allowing air flow into said pre-combustion region effecting the formation of an air-fuel mixture within said combustion chamber prior to the combustion process. 
     
     
         4 . The combustion chamber of  claim 3  wherein said air mixture apertures are arranged in at least two layers circumferentially disposed around the perimeter of said pre-combustion region, wherein the orthogonal axis of said air mixture apertures is directed to cause the intersection of air streams between apertures of different layers. 
     
     
         5 . The combustion chamber of  claim 4 , wherein said air mixture apertures comprise three layers disposed on a convex portion of said wall, wherein the apertures of each layer extend orthogonally relative to the surface of the wall. 
     
     
         6 . The combustion chamber of  claim 1 , wherein said plurality of apertures further comprise a group of secondary air feed apertures, circumferentially disposed around the perimeter of said secondary-combustion region downstream from said downstream group of confinement apertures, said secondary air feed apertures allowing air flow into said secondary-combustion region, prior to the exiting of the generated gases from said chamber, allowing for the combustion of residual air-fuel mixture when delayed in said secondary-combustion region. 
     
     
         7 . The combustion chamber of  claim 3  or  6 , wherein the apertures of at least one of: said upstream group of confinement apertures, said downstream group of confinement apertures, said group of air mixture apertures, or said group of secondary air feed apertures, comprise apertures selected from of the list consisting of:
 uniform apertures; 
 round apertures; and 
 apertures arranged equidistantly from one another. 
 
     
     
         8 . The combustion chamber of  claim 1 , wherein at least a portion of said wall enclosing said pre-combustion region is convex immediately upstream of said upstream group of confinement apertures. 
     
     
         9 . The combustion chamber of  claim 1 , wherein an orthogonal axis of the apertures of at least one group of:
 said upstream group of confinement apertures; and   said downstream group of confinement apertures,   is normal to said longitudinal axis.   
     
     
         10 . The combustion chamber of  claim 1 , comprising a circular cross section profile perpendicular to said longitudinal axis, wherein the ratio between the diameter of said cross section located between said pre-combustion region and said peak-combustion region and the diameter of said cross section at said gas outlet, is 3:2. 
     
     
         11 . The combustion chamber of  claim 1 , comprising a circular cross section profile perpendicular to said longitudinal axis, wherein the ratio between the diameter of said cross section located between said pre-combustion region and said peak-combustion region, and the length of said combustion chamber along said peak-combustion region and said secondary-combustion region is 7:10. 
     
     
         12 . The combustion chamber of  claim 1 , wherein said pre-combustion region comprises a dome-shaped cover. 
     
     
         13 . The combustion chamber of  claim 1 , further comprising a shell enclosing at least a portion of said combustion chamber and defining an interspace therebetween, wherein air flows into said interspace via an air inlet of said shell, and continues into said combustion chamber via said plurality of apertures. 
     
     
         14 . The combustion chamber of  claim 13 , wherein said shell comprises at least one exit aperture, for allowing air that entered said interspace to exit. 
     
     
         15 . (canceled) 
     
     
         16 . The combustion chamber of  claim 1 , wherein said combustion chamber resembles a shape selected from the list consisting of:
 a cylinder;   a tube;   a truncated cone;   a frustum;   a bifrustum;   a truncated bipyramid; and   an urn.   
     
     
         17 . (canceled) 
     
     
         18 . The combustion chamber of  claim 1 , wherein said heavy fuel oil comprises at least one selected from the list consisting of:
 diesel oil;   kerosene;   mazut;   naphtha;   asphalt;   petroleum;   bunker fuel;   residual fuel oil;   crude oil;   synthetic crude oil;   shale oil;   heavy crude oil;   extra heavy oil;   any of the above mixed with light oil or fuel or liquid hydrocarbon; and   any combination of the above.   
     
     
         19 . (canceled) 
     
     
         20 . The combustion chamber of  claim 1 , further comprising an air pump, operative for enhancing air flow into said chamber. 
     
     
         21 . The combustion chamber of  claim 1 , further comprising a turbofan, powered by the exhaust gases ejected from said combustion chamber, said turbofan operative for supplying mechanical energy to at least one component. 
     
     
         22 . A method for combustion of heavy fuel oil, said method comprising the procedures of:
 providing said fuel oil in a combustion chamber;   mixing said fuel oil with air to produce a combustible air-fuel mixture applied into a pre-combustion region of said combustion chamber;   forming an air curtain barrier between said pre-combustion region of said combustion chamber and a peak-combustion region of said combustion chamber;   forming an air curtain barrier between said peak-combustion region of said combustion chamber and a secondary-combustion region of said combustion chamber; and   initiating combustion of said air-fuel mixture, wherein the combustion is temporarily detained and confined within said peak-combustion region, prolonging said combustion within said peak-combustion region.   
     
     
         23 . The method of  claim 22 , further comprising the procedure of allowing air flow into said secondary-combustion region to combust residual fuel therein.