Patent ID: 8904972
Filing Date: 2014-12-09
Classification: F01K,F22G

Abstract:
1. A heat recovery steam generation system, comprising: at least one evaporator in a steam path configured to deliver steam to a steam turbine; at least one economizer coupled in series with the at least one evaporator in the steam path; a primary superheater and a finishing superheater, both in the steam path and configured to superheat steam from the at least one evaporator; an inter-stage attemperator in the steam path downstream of the primary superheater and upstream of the finishing superheater, wherein the inter-stage attemperator is configured to inject feedwater into the steam path; a control valve coupled to the inter-stage attemperator, wherein the control valve is configured to supply feedwater to the inter-stage attemperator for injection into the steam path; and a controller configured to control operation of the control valve and inter-stage attemperator, wherein the controller comprises a processor containing a feed-forward control using model-based predictive temperature control of a temperature of exhaust steam from the finishing superheater, and wherein the model-based predictive temperature control is configured to establish a profile for a set point steam temperature based on an inlet temperature of exhaust gas from a gas turbine such that the set point steam temperature may be reached only at or after the exhaust gas temperature reaches an isotherm.