Process and burner for hydrocarbon partial oxidation

Abstract

A hydrocarbon partial oxidation process for obtaining gaseous mixtures comprising hydrogen and carbon monoxide is carried out through a burner ( 10 ) comprising a mixing chamber ( 12 ) that has an inner side wall ( 12 a ) extending between at least one inlet opening ( 23, 23 a ) and an outlet opening ( 24 ), independent gaseous flows of hydrocarbons and oxygen, respectively, being continuously fed into said mixing chamber ( 12 ) to form a gaseous mixture advancing towards said outlet opening ( 24 ) to be fed into a combustion chamber ( 14 ) of the gaseous mixture itself; into said mixing chamber ( 12 ) and substantially in contact with the inner side wall ( 12 a ) thereof, a flow of an inert fluid is also fed in equicurrent to said gaseous mixture, with formation of a respective annular flow of inert fluid, enveloping said gaseous mixture from which it is substantially separated by a respective inner limit layer, said annular flow of inert fluid having, at said limit layer, an advancing speed at least equal to the speed of propagation of the flame in said gaseous mixture.

1 . Hydrocarbon partial oxidation process for obtaining gaseous mixtures comprising hydrogen and carbon monoxide, through a burner ( 10 ) comprising a mixing chamber ( 12 ) that has an inner side wall ( 12   a ) extending between at least one inlet opening ( 23 ,  23   a ) and an outlet opening ( 24 ), independent gaseous flows of hydrocarbons and oxygen, respectively, being continuously fed into said mixing chamber ( 12 ) to form a gaseous mixture advancing towards said outlet opening ( 24 ) to be fed into a combustion chamber ( 14 ) of the gaseous mixture itself, characterized in that, into said mixing chamber ( 12 ) and substantially in contact with the inner side wall ( 12   a ) thereof, a flow of an inert fluid is also fed in equicurrent to said gaseous mixture, with formation of a respective annular flow of inert fluid, enveloping said gaseous mixture from which it is substantially separated by a respective inner limit layer, said annular flow of inert fluid having, at said limit layer, an advancing speed at least equal to the speed of propagation of the flame in said gaseous mixture.  
   
   
       2 . Partial oxidation process according to  claim 1 , characterized in that the flow of inert fluid is fed close to the outlet opening ( 24 ) of the mixing chamber ( 12 ).  
   
   
       3 . Partial oxidation process according to  claim 1 , characterized in that helical motion is given to the flow of inert fluid.  
   
   
       4 . Partial oxidation process according to  claim 1 , characterized in that the flow of hydrocarbons and the flow of oxygen are fed at substantially the same axial speed.  
   
   
       5 . Partial oxidation process according to  claim 4 , characterized in that helical motion is given to at least one among the flow of hydrocarbons and the flow of oxygen.  
   
   
       6 . Partial oxidation process according to  claim 5 , characterized in that, to the flow of hydrocarbons and to the flow of oxygen, helical motions are given in opposite directions with respect to each other.  
   
   
       7 . Partial oxidation process according to  claim 6 , characterized in that said opposite helical motions have substantially the same momentum of momentum values.  
   
   
       8 . Partial oxidation process according to  claim 1 , characterized in that said inert fluid is steam.  
   
   
       9 . Burner ( 10 ) for hydrocarbon partial oxidation, for obtaining gaseous mixtures comprising hydrogen and carbon monoxide, of the type comprising a mixing chamber ( 12 ) in fluid communication with a combustion chamber ( 14 ), said mixing chamber ( 12 ) having an inner side wall ( 12   a ) extending between at least one inlet opening ( 23 ) and an outlet opening ( 24 ), independent gaseous flows of hydrocarbons and oxygen, respectively, being continuously fed into said mixing chamber ( 12 ) to form a gaseous mixture advancing towards said outlet opening ( 24 ) to be fed into said combustion chamber ( 14 ) of the gaseous mixture itself, characterized in that, into said mixing chamber ( 12 ) and substantially in contact with the inner side wall ( 12   a ) thereof, a flow of inert fluid is also fed in equicurrent to said gaseous mixture, so as to carry out the process of  claim 1 .  
   
   
       10 . Burner ( 10 ) according to  claim 9 , characterized in that a duct ( 26 ) carrying oxygen and a duct ( 28 ) carrying hydrocarbons arrive in said mixing chamber ( 12 ), said two ducts ( 26 ,  28 ) being substantially two coaxial and concentric cylindrical pipes, inner ( 30 ) and outer ( 32 ), contained in a cylindrical body ( 18 ) of the burner ( 10 ).  
   
   
       11 . Burner ( 10 ) according to  claim 10 , characterized in that the flow of inert fluid is fed into the mixing chamber ( 12 ) from a duct ( 34 ) that is substantially a cylindrical pipe ( 36 ), arranged coaxially and concentrically with the outer pipe ( 32 ) and contained in the cylindrical body ( 18 ).  
   
   
       12 . Burner ( 10 ) according to  claim 11 , characterized in that said cylindrical pipe ( 36 ) constitutes the inner side wall of the cylindrical body ( 18 ), an end portion of the side wall ( 12   a ) of the mixing chamber ( 12 ) being formed by a portion of cylindrical pipe ( 36 ) that is close to the outlet opening ( 24 ) of the cylindrical body ( 18 ).  
   
   
       13 . Burner ( 10 ) according to  claim 12 , characterized in that the outer pipe ( 32 ), coaxial to the cylindrical pipe ( 36 ), is shorter than the cylindrical pipe ( 36 ), the annular interspace between the cylindrical pipe ( 36 ) and the outer pipe ( 32 ) feeding the inert fluid.  
   
   
       14 . Burner ( 10 ) according to  claim 13 , characterized in that the inner pipe ( 30 ), coaxial to the outer pipe ( 32 ), is shorter than the outer pipe ( 32 ).  
   
   
       15 . Burner ( 10 ) according to  claim 14 , characterized in that, in the end portion of the inner pipe ( 30 ), in the end portion of the interspace between inner pipe ( 30 ) and outer pipe ( 32 ) and in the end portion of the interspace between outer pipe ( 32 ) and cylindrical pipe ( 36 ), swirlers ( 40 ,  42 ,  44 ) are provided.  
   
   
       16 . Burner ( 10 ) according to  claim 14 , characterized in that, in the wall of the cylindrical pipe ( 36 ) that defines the portion of cylindrical body ( 18 ) inserted in the combustion chamber ( 14 ), a cylindrical recess ( 46 ) is provided, in fluid communication with an inlet fitting ( 48 ) and an outlet fitting ( 50 ) of a cooling fluid.  
   
   
       17 . Burner ( 10 ) according to  claim 16 , characterized in that said inlet fitting ( 48 ) and said outlet fitting ( 50 ) are arranged outside the combustion chamber ( 14 ) and in that, in the cylindrical recess ( 46 ), it is provided a cylindrical baffle ( 52 ) that defines two coaxial and concentric inner ( 54 ) and outer ( 56 ) cylindrical chambers, in fluid communication with each other and, respectively, with the inlet fitting ( 48 ) and with the outlet fitting ( 50 ).  
   
   
       18 . Burner ( 10 ) according to  claim 17 , characterized in that the inner cylindrical chamber ( 54 ) defines the duct ( 34 ) carrying inert fluid and the end portion of the side wall ( 12   a ) of the mixing chamber ( 12 ).