Patent ID: 6898935

Claim:
A method of cooling a steam turbine having internal moving components to a predetermined temperature, wherein the steam turbine comprises injection points, the method which comprises the steps of: (a) stopping the flow of steam; (b) introducing a flow of nitrogen to the turbine until the turbine reaches the predetermined temperature while controlling the flow of nitrogen at the injection points to prevent damage to the moving components of the turbine by achieving uniform cooling of the internal moving components; and (c) stopping the flow of nitrogen wherein the injection points comprise a main steam inlet piping connected to the turbine and a cold reheat line connected to the turbine such that a flow of steam first moves from the main steam inlet piping to the turbine and then the flow of steam moves from the turbine to the cold reheat line during operation, wherein the steam turbine further comprises a hot reheat line connected to the turbine and a condenser vacuum relief line connected to the turbine such that a flow of steam first moves from the hot reheat line to the turbine and then the flow of steam moves from the turbine to the condenser vacuum relief line during operation, and wherein the flow of nitrogen in also moves in the hot reheat line during Step (b).