Method and apparatus for reducing combustion residues in exhaust gases

Abstract

A method and an apparatus for reducing combustion residues, particularly pollutants, in exhaust gases generated from the combustion of fuels such as fossil fuels, wood and similar. The exhaust gases are treated before releasing them in the environment. The exhaust gases treatment includes performing a post-combustion process by submitting the exhaust gases to radiant heat in order to increase the exhaust gases temperature to a value sufficient to cause self-combustion.

1 . A method for reducing combustion residues in exhaust gases generated from the combustion of a fuel, including treating the exhaust gases before releasing them in the environment, wherein: 
 said treating the exhaust gases includes a post-combustion process performed by;    feeding the exhaust gases to a radiant combustion reactor including a radiant combustion chamber and means adapted to supply energy to the radiant combustion chamber, the radiant combustion reactor being adapted to transform the supplied energy into radiant energy radiating within the radiant combustion chamber; and    submitting the exhaust gases to the radiant energy in the radiant combustion reactor, to raise the temperature of exhaust gases till a value sufficient to cause self-combustion.    
     
     
         2 . The method according to  claim 1 , in which within the radiant combustion reactor the temperature of the exhaust gases is increased to a value in the range from approximately 250° C. to approximately 1800° C., particularly from approximately 400° C. to approximately 1400° C., preferably from approximately 900° C. to approximately 1200° C. and, even more preferably, from approximately 900° C. to approximately 1100° C.  
     
     
         3 . The method according to  claim 1 , further comprising submitting the exhaust gases to filtering so as to substantially eliminate residual uncombusted dust and particulate material present in the exhaust gases, said filtering being performed at least after the post-combustion.  
     
     
         4 . The method according to  claim 3 , in which said post-combustion process is carried out in at least two stages, the method comprising submitting the exhaust gases to said filtering also between the two stages.  
     
     
         5 . The method according to  claim 3 , in which said filtering includes one or more among an active and an inactive filtering.  
     
     
         6 . The method according to  claim 1 , further including pre-heating the exhaust gases before performing the post-combustion process.  
     
     
         7 . The method according to  claim 6 , in which said pre-heating the exhaust gases includes bringing the exhaust gases temperature over approximately 400° C., preferably in the range from approximately 400° C. to approximately 700° C.  
     
     
         8 . The method according to  claim 7 , in which said pre-heating the exhaust gases includes accelerating and compressing the exhaust gases.  
     
     
         9 . The method according to claims  1 , further including lowering the exhaust gases temperature after performing the post-combustion process before releasing the post-combusted exhaust gases in the environment.  
     
     
         10 . The method according to  claim 9 , in which the temperature of the post-combusted exhaust gases is lowered to a value in the range from approximately 50° C. to approximately 150° C.  
     
     
         11 . The method according to  claim 3 , in which after said filtering the temperature of the post-combusted exhaust gases is lowered to a value in the range from approximately 50° C. to approximately 150° C.  
     
     
         12 . The method according to  claim 9 , in which said lowering the temperature of the exhaust gases includes: 
 providing a heat exchanger;    causing the post-combusted gases pass through the heat exchanger;    causing the exhaust gases to be post-combusted invest the heat exchanger, in order to exploit heat released by post-combusted exhaust gases for pre-heating the exhaust gases to be post-combusted.    
     
     
         13 . The method according to claims  1 , in which the post-combustion process is carried out continuously, with the exhaust gases to be submitted to post-combustion being in substantially contiguity relationship with the post-combusted exhaust gases within the radiant combustion reactor.  
     
     
         14 . The method according to any one of claims  1 , in which the post-combustion process is carried out partially continuously, with the exhaust gases to be submitted to post-combustion being separated from the post-combusted exhaust gases within the radiant combustion reactor at a time of the order of 10 −6  to 10 −2  seconds.  
     
     
         15 . The method according to  claim 1 , in which the post-combustion process is carried out discontinuously, with the exhaust gases already submitted to post-combustion being kept substantially separated from the exhaust gases to be submitted to post-combustion.  
     
     
         16 . An apparatus for reducing combustion residues, particularly pollutants, in exhaust gases generated from the combustion of fuel, including a system for the treatment of exhaust gases before releasing them in the environment, wherein 
 said exhaust gases treatment system includes a radiant combustion reactor wherein the exhaust gases pass through, in order to be submitted to radiant energy for raising the exhaust gases temperature to a value sufficient to cause self-combustion, thereby a post-combustion process of the exhaust gases is performed before releasing them in the environment.    
     
     
         17 . The apparatus according to  claim 16 , in which within the radiant combustion reactor the exhaust gases temperature is increased to a value in the range from approximately 250° C. to approximately 1800° C., Particularly from approximately 400° C. to approximately 1400° C., preferably from approximately 900° C. to approximately 1200° C., more preferably from approximately 900° C. to approximately 1100° C.  
     
     
         18 . The apparatus according to  claim 16 , further including a filtering device adapted to substantially eliminate residual uncombusted dust and particulate material present in the exhaust gases, said filtering device being located at least downstream the radiant combustion reactor.  
     
     
         19 . The apparatus according to  claim 18 , in which said radiant combustion reactor includes two chambers at the end, one downstream the other, the filtering device being additionally located between the two chambers.  
     
     
         20 . The apparatus according to  claim 18 , in which the filtering device includes one or more among active filters and inactive filters, particularly selective filters based on ceramic and zeolite materials.  
     
     
         21 . The apparatus according to any one of claims  16 , further including a pre-heating chamber, upstream the radiant combustion reactor, for pre-heating the exhaust gases before performing the post-combustion process.  
     
     
         22 . The apparatus according to  claim 21 , in which in said pre-heating chamber the exhaust gases are pre-heated to a temperature over approximately 400° C., preferably in the range from approximately 400° C. to approximately 700° C.  
     
     
         23 . The apparatus according to  claim 21 , in which said pre-heating chamber includes a device for accelerating and compressing the exhaust gases, particularly one or more among a fan or an arrangement of fans, a turbine, a turbo compressor.  
     
     
         24 . The apparatus according to  claim 23 , in which said pre-heating chamber further includes a Venturi tube for further accelerating the exhaust gases.  
     
     
         25 . The apparatus according to  claim 16 , further including a heat-exchange device downstream the radiant combustion reactor, for lowering the exhaust gases temperature after performing the post-combustion process before releasing the post-combusted exhaust gases in the environment.  
     
     
         26 . The apparatus according to  claim 25 , in which the heat-exchange device is adapted to lower the temperature of the post-combusted exhaust gases to a value in the range from approximately 50° C. to approximately 150° C.  
     
     
         27 . The apparatus according to  claim 25 , in which said heat-exchange device is placed downstream said filtering device.  
     
     
         28 . The apparatus according to claims  25 , in which said heat-exchange device is operatively coupled with the pre-heating chamber, so that the heat released by the post-combusted exhaust gases in the heat-exchange device is exploited for pre-heating the exhaust gases in the pre-heating chamber.  
     
     
         29 . The apparatus according to claims  16 , further including a control unit, particularly an electronic, programmable control unit, for the post-combustion process control.  
     
     
         30 . The apparatus according to of claims  16 , in which the radiant combustion chamber includes an enclosed path for the exhaust gases, and a heating device associated with the enclosed path for heating walls.  
     
     
         31 . The apparatus according to  claim 30 , in which said heating includes Joule-effect heaters.  
     
     
         32 . The apparatus according to  claim 31 , in which said enclosed path includes system of ducts including at least one duct for the passage of the exhaust gases, and having associated therewith electrical resistors for heating the duct walls.  
     
     
         33 . The apparatus according to  claim 32 , in which said arrangement of ducts comprises at least one among a substantially “U”-shaped, a substantially double “U”-shaped or a substantially “W”-shaped arrangement of ducts, at least one of said ducts having wound around it at least one spiral resistor controllably powered for heating the duct walls.  
     
     
         34 . The apparatus according to  claim 31 , comprising an arrangement of ducts associated with at least one heat radiating panel, having embedded therewith a Joule-effect heat generator.  
     
     
         35 . The apparatus according to  claim 30 , in which said heating system includes an optical radiation source, particularly a laser.  
     
     
         36 . The apparatus according to  claim 35 , in which said optical radiation source comprises at least one laser.  
     
     
         37 . The apparatus according to  claim 36 , in which at least one said laser is operated in pulsed mode.  
     
     
         38 . The apparatus according to  claim 36 , further comprising an optical radiation reflecting/deflecting arrangement for reflecting/deflecting the optical radiation onto the enclosed path.  
     
     
         39 . The apparatus according to claims  16 , in which a gases separation system is provided within the radiant combustion reactor for determining a separation of different parts of the exhaust gases undergoing different phases of the post-combustion process.  
     
     
         40 . The apparatus according to  claim 39 , in which said gases separation system includes a rotor rotatably arranged inside the radiant combustion reactor.  
     
     
         41 . A system including a fuel combustion apparatus in which a fuel combustion process takes place, and an apparatus for treating exhaust gases originated by the combustion process, wherein said apparatus for treating the exhaust gases includes a radiant combustion reactor wherein the exhaust gases are caused to pass through, to be submitted to radiant energy for increasing the exhaust gases temperature to a value sufficient to cause self-combustion, thereby a post-combustion process of the exhaust gases is performed before releasing them in the environment.  
     
     
         42 . The system according to  claim 41 , in which said fuel combustion apparatus is an internal combustion engine, particularly a vehicle engine.  
     
     
         43 . The system according to  claim 41 , in which said fuel combustion apparatus is a burner of heating system.  
     
     
         44 . The system according to  claim 41 , in which said fuel combustion apparatus is a steam boiler for the production of electrical power.