A burner assembly comprising: • at least two fuel gas canals; • at least one oxidant canal and • at least one exit face at which the at least two fuel gas canals or at least one of the oxidant canals or both terminate, whereby the burner assembly further comprises: a) means for supplying an oxidant stream; b) means to inject said oxidant stream in said at least one oxidant fluid canal to create at least one injected oxidant stream; c) means for supplying a fuel gas stream; d) means to inject said fuel gas stream in said at least two fuel gas canals to create at least two injected fuel gas streams; and wherein the directions of injection of the at least one injected oxidant stream and the at least two injected fuel gas streams are substantially converging and intersect at a combustion zone downstream of the burner assembly, characterized in that: • the at least two fuel gas canals comprise an inner fuel-conducting passage forming an inner fuel gas outlet and an outer fuel-conducting passage forming an outer fuel gas outlet, said inner and said outer fuel-conducting passages being coaxially arranged; and • the means to inject said fuel gas stream comprises a fuel gas distributor for receiving the fuel gas stream from the means for supplying a fuel gas stream and having: i) a first fuel gas chamber in fluid connexion with the inner fuel-conducting passage of the at least two fuel gas canals, said first fuel gas chamber having a first inlet for receiving fuel gas supplied by the means for supplying a fuel gas stream; ii) a second fuel gas chamber in fluid connexion with the outer fuel-conducting passage of the at least two fuel gas canals, said second fuel gas chamber having a second inlet for receiving fuel gas supplied by the means for supplying a fuel gas stream; and iii) fuel gas flow control means (140, 141, 142, 150, 160, 162) for controlling the flow of the fuel gas stream to respectively the first and second inlet, • whereby the means for supplying a fuel gas stream supplies the fuel gas stream to one of the first and second inlets, • whereby the first and second fuel gas chambers are in fluid connection with one another via the other of the first and second inlets, and • whereby the fuel gas flow control means (140, 150, 160) is equipped to control the portion of the fuel gas stream flowing from said one of the first and second fuel gas chambers to the other fuel gas chamber via the other of the first and second inlets. • at least two fuel gas canals; • at least one oxidant canal and • at least one exit face at which the at least two fuel gas canals or at least one of the oxidant canals or both terminate, a) means for supplying an oxidant stream; b) means to inject said oxidant stream in said at least one oxidant fluid canal to create at least one injected oxidant stream; c) means for supplying a fuel gas stream; d) means to inject said fuel gas stream in said at least two fuel gas canals to create at least two injected fuel gas streams; • the at least two fuel gas canals comprise an inner fuel-conducting passage forming an inner fuel gas outlet and an outer fuel-conducting passage forming an outer fuel gas outlet, said inner and said outer fuel-conducting passages being coaxially arranged; and • the means to inject said fuel gas stream comprises a fuel gas distributor for receiving the fuel gas stream from the means for supplying a fuel gas stream and having: i) a first fuel gas chamber in fluid connexion with the inner fuel-conducting passage of the at least two fuel gas canals, said first fuel gas chamber having a first inlet for receiving fuel gas supplied by the means for supplying a fuel gas stream; ii) a second fuel gas chamber in fluid connexion with the outer fuel-conducting passage of the at least two fuel gas canals, said second fuel gas chamber having a second inlet for receiving fuel gas supplied by the means for supplying a fuel gas stream; and iii) fuel gas flow control means (140, 141, 142, 150, 160, 162) for controlling the flow of the fuel gas stream to respectively the first and second inlet, i) a first fuel gas chamber in fluid connexion with the inner fuel-conducting passage of the at least two fuel gas canals, said first fuel gas chamber having a first inlet for receiving fuel gas supplied by the means for supplying a fuel gas stream; ii) a second fuel gas chamber in fluid connexion with the outer fuel-conducting passage of the at least two fuel gas canals, said second fuel gas chamber having a second inlet for receiving fuel gas supplied by the means for supplying a fuel gas stream; and iii) fuel gas flow control means (140, 141, 142, 150, 160, 162) for controlling the flow of the fuel gas stream to respectively the first and second inlet, • whereby the means for supplying a fuel gas stream supplies the fuel gas stream to one of the first and second inlets, • whereby the first and second fuel gas chambers are in fluid connection with one another via the other of the first and second inlets, and • whereby the fuel gas flow control means (140, 150, 160) is equipped to control the portion of the fuel gas stream flowing from said one of the first and second fuel gas chambers to the other fuel gas chamber via the other of the first and second inlets.