Once-through evaporator systems
AssigneeGeneral Electric Technology GmbH
InventorsPetrus Johannes Koller, Rudolf Zinniker, Hans Ulrich Lenherr, Alexander Taylor, Stefan Lukas Gysel
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Abstract
The present application provides a once-through evaporator system. The once-through evaporator system may include a number of once-through evaporator sections with a distribution valve and a level sensor and a controller in communication with each distribution valve. The controller provides the distribution valve with a position set point and biases the position set point via a feedforward signal based on a fill level as determined by the level sensor in each of the once-through evaporator sections.
Claims15
A system, comprising:
- a once-through evaporator system, comprising:
- a plurality of once-through evaporator sections, wherein each of the plurality of once-through evaporator sections comprises a distribution valve and a level sensor;
- a controller configured to control filling of the plurality of once-through evaporator sections for a first duration of time during a start-up procedure of the once-through evaporator system, wherein the controller is in communication with each distribution valve, the controller is configured to provide each distribution valve with a position set point, and the controller is configured to bias the position set point via a first feedforward signal based on a fill level as determined by the level sensor in each of the plurality of once-through evaporator sections for the first duration of time during the start-up procedure.
A method, comprising:
- feeding a feedwater into a once-through evaporator section through a distribution valve at a feedwater flow rate during a start-up procedure of a once-though evaporator system;
- controlling the feedwater flow rate in a filling control mode during the start-up procedure via a flow controller controlling the distribution valve, wherein the filling control mode comprises biasing a set point via a first feedforward signal based on a fill level in the once-through evaporator section, wherein the fill level is based on feedback from a level sensor of the once-through evaporator section, and wherein the set point comprises a position set point for the distribution valve;
- controlling the feedwater flow rate via a dynamic feedforward signal in a second control mode after the filling control mode during the start-up procedure;
- and
- controlling the feedwater flow rate via the dynamic feedforward signal and temperature feedback control based on once-through evaporator section exit temperatures in a third control mode after the second control mode.
Dependencies are inferred from the claim text.