Method and device for regulating the production of steam in a steam plant

Abstract

A method for regulating the production of steam from feed water in an evaporator of a steam plant is provided. A state regulator calculates a plurality of states of a medium in the evaporator by means of an observer and, on the basis thereof, determines a feed water mass flow rate as a regulating variable. In order to obtain a stable and precise regulation of the temperature of the steam, the state regulator is a linear-quadratic regulator.

1 - 10 . (canceled) 
     
     
         11 . A method for regulating the production of steam from feed water in an evaporator of a steam power plant, comprising:
 calculating a plurality of medium states in an evaporator by a state controller by means of an observer; and   determining from the plurality of medium states a feed-water mass flow as a manipulated variable,   wherein the state controller is a linear-quadratic controller.   
     
     
         12 . The method as claimed in  claim 11 ,
 wherein a setpoint value for the feed-water mass flows is transmitted to an additional controller for controlling the feed-water mass flow.   
     
     
         13 . The method as claimed in  claim 11 , wherein an enthalpy of the medium is used as a state variable for calculating a medium state. 
     
     
         14 . The method as claimed in  claim 13 , wherein deviations of the absolute enthalpies from enthalpy setpoint values are used as state variables. 
     
     
         15 . The method as claimed in  claim 11 ,
 wherein a non-linear control system is used, and   wherein the control system is linearized within a predetermined deviation band around an operating point.   
     
     
         16 . The method as claimed in  claim 15 , wherein the operating point is actualized by using measured values. 
     
     
         17 . The method as claimed in  claim 15 , wherein the control system of the state controller includes a matrix equation, for the calculation of which use is made of medium values which are measured during the steam. 
     
     
         18 . The method as claimed in  claim 11 , wherein the observer is a Kalman filter which is designed upon a linear-quadratic state feedback. 
     
     
         19 . The method as claimed in  claim 11 , wherein the observer calculates the heat which is yielded to the medium in the evaporator. 
     
     
         20 . A device for regulating the production of steam from feed water in an evaporator of a steam power plant, comprising:
 a control system which includes an observer and a state controller which is preconfigured to calculate a plurality of medium states in an evaporator by means of the observer and to determine therefrom a feed-water mass flow as a manipulated variable of the control system,   wherein the state controller is a linear-quadratic controller.