Pulse detonation particulate agglomerator

Abstract

The burning of fuel (e.g., coal) generates an exhaust flow containing particles. The flow is passed through a pulsed combustion agglomerator. The agglomerator is cyclically operated by introducing a fuel and oxidizer charge to at least one conduit, initiating combustion of the charge. The combustion generates a shock wave to which the flow is exposed causing partial agglomeration of the particles. The flow is passed through a particle removal system and exhausted.

1 . An apparatus comprising: 
 a combustor;    an exhaust flowpath extending from the combustor    a particulate removal device along the exhaust flowpath; and    a pulsed-combustion particle agglomeration system along the exhaust flowpath between the furnace and the removal device and comprising: 
 a source of fuel and oxidizer;  
 a plurality of combustion conduits coupled to the source to receive charges of said fuel and oxidizer; and  
 a plurality of igniters coupled to the combustion conduits to ignite the charges.  
   
   
   
       2 . The apparatus of  claim 1  wherein: 
 the combustor is a coal-burning furnace.    
   
   
       3 . The apparatus of  claim 2  further comprising: 
 pendant boiler tubes receiving heat from combustion of the coal to heat steam in the tubes, the system being downstream of the tubes along the exhaust flowpath.    
   
   
       4 . The apparatus of  claim 3  further comprising: 
 an economizer in the exhaust flowpath; and    an air heater in the exhaust flowpath, the pulsed-combustion particle agglomeration system being between the economizer and the air heater.    
   
   
       5 . The apparatus of  claim 2  further comprising: 
 a plurality of pulverizers delivering pulverized coal to the furnace.    
   
   
       6 . The apparatus of  claim 1  wherein: 
 said combustion conduits have outlets aimed transverse to a downstream direction of the flowpath.    
   
   
       7 . The apparatus of  claim 1  wherein: 
 at least four of said combustion conduits are positioned at essentially a common streamwise location along the exhaust flowpath.    
   
   
       8 . The apparatus of  claim 1  further comprising: 
 a smokestack forming an outlet of the flowpath to atmosphere.    
   
   
       9 . The apparatus of  claim 1  wherein the source comprises: 
 a first source of said fuel, said fuel consisting in majority part, by mass, of fuel selected from the group consisting of hydrogen, hydrocarbon fuels, and their mixtures; and    a second source of said oxidizer, said oxidizer consisting essentially of air.    
   
   
       10 . The apparatus of  claim 1  wherein: 
 said combustion conduits are configured to operate at a cycle frequency of at least 1.5 Hz.    
   
   
       11 . The apparatus of  claim 1  wherein: 
 there are at least six of said combustion conduits.    
   
   
       12 . The apparatus of  claim 1  wherein: 
 there are at least four of said combustion conduits positioned in two out-of-phase groups.    
   
   
       13 . The apparatus of  claim 1  wherein: 
 said combustion conduits have lengths of 0.5-4 m and cross-sectional areas of 5-150 cm 2 .    
   
   
       14 . An apparatus comprising: 
 a combustor;    an exhaust flowpath extending from the combustor;    a particulate removal device along the exhaust flowpath; and    pulsed-combustion means for encouraging particle agglomeration along the exhaust flowpath between the combustor and the removal device.    
   
   
       15 . The apparatus of  claim 14  wherein the combustor is a fossil fuel-burning furnace;  
   
   
       16 . The apparatus of  claim 14  being a boiler system  
   
   
       17 . A method for operating a plant comprising: 
 burning a plant fuel and generating a flow containing particles;    passing the flow through a pulsed detonation particulate agglomerator including cyclically: 
 introducing a fuel and oxidizer charge to at least one conduit;  
 initiating combustion of the charge; and  
 exposing the coal combustion products flow to shock waves generated by the pulsed detonation combustion causing agglomeration of the particles;  
   passing the flow through a particulate removal system; and    exhausting the flow.    
   
   
       18 . The method of  claim 17  wherein: 
 the plant fuel is selected from the group consisting of coal, fuel oil, hydrocarbon gas biomass, trash, and combinations thereof.    
   
   
       19 . The method of  claim 17  further comprising: 
 recirculating a portion of the flow.    
   
   
       20 . The method of  claim 17  wherein: 
 the exposing comprises passing the flow past and exposing said flow to said shock waves from a plurality of said conduits.    
   
   
       21 . The method of  claim 17  wherein: 
 the exposing comprises passing the flow between opposed outlets of one or more pairs of said conduits.    
   
   
       22 . The method of  claim 17  wherein: 
 the agglomeration enhances mass extraction by the particulate removal system.    
   
   
       23 . The method of  claim 17  wherein: 
 the charge comprises hydrogen as a by weight majority of the fuel.    
   
   
       24 . The method of  claim 17  wherein: 
 the at least one conduit is operated with an air purge before each charge introduction.    
   
   
       25 . The method of  claim 17  wherein: 
 the at least one conduit is operated at a cycle frequency of at least 1.5 Hz.