Importance

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Abstract

The invention refers to a forced flow steam generator (10) and to a method for its operation. The forced flow steam generator (10) has a combustion chamber (11) with a burner arrangement (20). A fuel (B) and a mixture (G) consisting of pure oxygen and flue gas (R) are fed into the combustion chamber (11) or to the burner arrangement (20) for combusting. A flue gas duct (27) is connected to the combustion chamber (11) in the flow direction (S) of the flue gas (R), and a flue gas passage (26) is connected to the flue gas duct. The flue gas (R) for the oxygen-flue gas mixture (G) is fed back from the flue gas passage (26) via a flue gas recirculation line (28). The forced flow steam generator (10) is operated in the so-called oxyfuel process. A plurality of auxiliary heating surfaces (35) are arranged in the flue gas duct (27) downstream of the burner arrangement (20). Between the burner arrangement (20) and the auxiliary heating surfaces (35), provision is made for a wall heating surface arrangement (36) which at least partially covers a combustion chamber wall section (38) of the combustion chamber wall (12) which delimits the combustion chamber (11). For this purpose, the wall heating surface arrangement (36) has a plurality of wall heating surfaces (37) which butt against the respectively associated segment of the combustion chamber wall section (38). The operating medium (A) flows through the wall heating surface arrangement (36) and in this way thermal energy is dissipated from the flue gas (R) in order to limit the heating of the operating medium (A) in the combustion chamber wall tubes (13) and therefore to limit wall tube temperatures in the upper section of the boiler.

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First Claim