Steam generation plant and method for operation and retrofitting of a steam generation plant

A method for operating a steam generation plant comprising a steam generator comprising a combustor, an evaporator, a superheater, an intermediate superheater, a condenser, and feed water pre-heaters heated regeneratively by steam;

• a set of steam turbines comprising a high pressure turbine, an intermediate pressure turbine, and a low pressure turbine;
• a condensate circuit connected to the steam generator, said circuit comprising said condenser;
• a flue gas line connected to the combustor;
• an air feed line for supplying combustion air to the combustor;
• and an air pre-heater wherein the combustion air is pre-heated by the flue gas, the flue gas line and the air feed line being connected through the air pre-heater;
• the method comprising:
• diverting an air stream from the air feed line downstream of the air-preheater to an air separation plant via an air line;
• cooling the air stream in the air line by condensate from said condensate circuit;
• separating the air stream in the air separation plant into an O2 fraction and an N2 fraction;
• sending the O2 fraction to the combustor through an oxygen line.

A method for retrofitting a steam generation plant comprising a steam generator comprising a combustor, an evaporator, a superheater, an intermediate superheater, a condenser, and feed water pre-heaters heated regeneratively by steam;

• a set of steam turbines comprising a high pressure turbine, an intermediate pressure turbine, and a low pressure turbine;
• a condensate circuit connected to the steam generator, said circuit comprising said condenser;
• a flue gas line connected to the combustor;
• an air feed line for supplying combustion air to the combustor;
• and an air pre-heater wherein the combustion air is pre-heated by the flue gas, the flue gas line and the air feed line being connected through the air pre-heater;
• the method comprising:
• connecting an air line to the air feed line at a connection downstream of the air pre-heater;
• installing air coolers in the air line downstream of the connection, wherein the air coolers are cooled by condensate from the condensate circuit;
• installing an air separation plant in the air line downstream of the air coolers, the separation plant separating an air stream in the air line into an O2 fraction and an N2 fraction, the separation plant having an oxygen outlet for the oxygen fraction;
• connecting the oxygen outlet to the combustor by means of an oxygen line.