METHOD FOR OPERATING A CONTINUOUS FLOW STEAM GENERATOR

摘要

#CMT# #/CMT# The forced-flow steam generator (1) has one or more heating surfaces (2, 4) in its economizer (2) and vaporizer (4). A desired value of mass flowrate is made available to equipment adjusting the feedwater supply. At the same time a correction factor (K) is taken into account. This compensates for the rate of enthalpy- or density variation in the input flow to the heating surfaces. The correction factor is derived from the sum of derivatives with respect to time, of the density of the flow at both the inlets to and the outlets from the heating surfaces. #CMT# : #/CMT# An independent claim is included for a once-through or forced-flow steam generator. #CMT#USE : #/CMT# For operating a forced-flow steam generator used in turbine plant. #CMT#ADVANTAGE : #/CMT# Predictive feedwater flow control is further improved by taking into account feedwater enthalpy and density variations. The enthalpy of steam produced at the steam generator outlet is especially stable. This remains true under conditions of variable loading. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a block schematic diagram of the steam generator and its control system. 1 : steam generator 2 : economizer 4 : vaporizer 20 : servomotor 22 : throttling valve 24 : flowmeter K : correction factor.