Superheated Steam Temperature Control Research Articles

Dynamic Matrix Control of Steam Temperature in Fossil Power Plants

This paper presents the design and simulation of a multivariable predictive controller (DMC) applied to steam temperature control of a fossil power plant. The purpose of this control is to regulate steam temperature in the reheater and the superheater, manipulating burner inclination and attemperation flow. Process response is shown when design parameters of control are changed. Performance of this control is compared to classical PID controller. The benefit of using DMC is to employ only one controller, considering the interactions between both control loops, superheater and reheater steam temperature control.

Optimal Control of Superheated Steam Temperature in Steam Turbine Power Plants

The article presents a synthesis of optimal control of superheated steam temperature in main propulsion boilers of steam turbine power plants. Asteam superheater installed on board t/t GIEWONT has been used for this study. A mathematical model of the superheater has been defined accounting for manoeuvring states and sea passage. The paper also presents a method of correcting nonlinearities, the compensation of measurable disturbances based on the total invariance condition and the compensation of nonmeasurable disturbances based on the internal model principle. Furthermore, an optimal control law has been determined for a properly chosen quadratic performance functional on the basis of an equivalent Smith's predictor. The predictor, combined with a full rank observer, generates the superheated steam temperature control. Finally, the optimal system was verified by a digital simulation method using the program MATLAB (The Math Works 1994).

Application of Super-Real-Time Simulation Control(SRTC) by Parallel Processing to Boiler Steam Temperature Control.

This paper has proposed a method which improves superheater and reheater steam temperature control in sliding pressure operation of a once-through boiler. The proposed control system is based on the super-real-time simulation in which a physical model is introduced to present the boiler dynamics within most of the operating range of load. The optimal actuating signals, such as spray flow and gas recirculation flow rate, have been determined by solving the physical model equation in order to keep steam temperature constant at every specified time interval with the aid of parallel microprocessors. The predictive action of SRTC compensates the lag of temperature dynamics at the change in load so that it stabilizes the control system much better than conventional PID feedback control. It is shown in this paper that the method has been successfully applied to a 1000 MW power plant.

An Optimal Multivariable Controller With Application to Steam Temperature Control in a Boiler

An optimal multivariable controller has been designed for superheater steam temperature control in a drum boiler. The controller takes the form of a linear quadratic regulator with supplementary states for added integral action. By means of a nonlinear model of the power plant, the performance of the controller is compared with that of the existing plant control system which consists of a set of PI controllers with feedforward action. The simulation results indicate that the superior performance of the digital controller justifies the expense of a control system retrofit.

A CAD Environment for the Design of Power Plant Control Systems

Fidelity of engineering simulation of thermal generating units has been remarkably enhanced with the introduction of modular modelling computer codes implementing a strict correspondence between plant components and submodels (or modules). On the contrary, the control system has commonly been given a conceptual representation, where the correspondence between the individual elements of a real control system and the conceptual elements realizing the control functions in the simulator is quite difficult to manage. Control system engineering is essentially based on standardization of system specification documents to which any design or evaluation function should be unambiguously referred. To meet such engineering requirement, an existing power plant simulation code has been equipped with a CAE system for control design, which, besides the basic functions of any engineering CAD system (including software production) allows automatical tuning of the industrial tunable controllers. An application to superheated steam temperature control of a drum boiler is considered.

A Steam Generator Dynamic Mathematical Modelling and Its Using for Adaptive Control Systems Testing

The dynamic once-through subcritical steam generator model, based on the plant design data, is presented. This model allows the investigation of power plant system transients . Detailed description of the simulation results is documented on the example of once-through subcritical steam generator o f 200 MW power unit. For the purpose of both the similaritv with the physical process and intelligibilitv of the model for a design engineer, familiar with technology, the structural boiler model was chosen. This one is composed of the following parts: combustion system, evaporator, uncontrolled and controlled superheaters, main steam line, and a representation o f the boiler load (steam consumer-reheat turbine). The boiler model is applied both to investigate the dynamical behavior of uncontrolled plant and to verify controller s and control concepts too. As the example of the model used for control testing the cascade superheated steam temperature control is described. The superheater model taken from the whole large boiler model was completed with regulating unit, nonlinearities, etc. Various controllers, especially PI and LQ STC, were compared in the role of the main controller.

Fluidized bed heating apparatus

This paper presents the design and simulation of a multivariable predictive controller (DMC) applied to steam temperature control of a fossil power plant. The purpose of this control is to regulate steam temperature in the reheater and the superheater, manipulating burner inclination and attemperation flow. Process response is shown when design parameters of control are changed. Performance of this control is compared to classical PID controller. The benefit of using DMC is to employ only one controller, considering the interactions between both control loops, superheater and reheater steam temperature control.