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Advanced Control Techniques

General Reeerences Seborg, Edgar, and Mellichamp, Frocess Dynamics and Control, Wiley, New York. 2004. Stephanopoulos, Chemical Frocess Control An Introduction to Theory and FracUce, Prentice-Hall, Englewood Cliffs, N.J., 1984. Shinskey, Frocess Control Systems, 4th ed., McGraw-Hill, New York, 1996. Ogunnaike and Ray, Frocess Dynamics, Modeliry and Control, Oxford University Press, New York, 1994. [Pg.21]

While the single-loop PID controller is satisfactory in many process applications, it does not perform well for processes with slow dynamics, time delays, frequent disturbances, or multivariable interactions. We discuss several advanced control methods below that can be implemented via computer control, namely, feedforward control, cascade control, time-delay compensation, selective and override control, adaptive control, fuzzy logic control, and statistical process control. [Pg.21]

Feedforward Control If the process exhibits slow dynamic response and disturbances are frequent, then the apphcation of feedforward control may be advantageous. Feedforward (FF) control differs from feedback (FB) control in that the primary disturbance or load (D) is measured via a sensor and the manipulated variable (H) is adjusted so that deviations in the controlled variable from the set point are minimized or eliminated (see Fig. 8-31). By taking control action based on measured disturbances rather than controlled variable error, the controller can reject disturbances before they affect the controlled variable Y. To determine the appropriate settings for the manipulated variable, one must develop mathematical models that relate [Pg.21]

8-31 Simplified block diagrams for feedforward and feedback control. [Pg.21]

These models can be based on steady-state or dynamic analysis. The [Pg.21]

General References Seborg, Edgar, and Mellichamp, Process Dynamics [Pg.21]

Feedforward Control If the process exhibits slow dynamic [Pg.21]


Regulatory Control For most batch processes, the discrete logic reqmrements overshadow the continuous control requirements. For many batch processes, the continuous control can be provided by simple loops for flow, pressure, level, and temperature. However, very sophisticated advanced control techniques are occasionally apphed. As temperature control is especially critical in reactors, the simple feedback approach is replaced by model-based strategies that rival if not exceed the sophistication of advanced control loops in continuous plants. [Pg.754]

PID control, advanced control techniques, control loop performance monitoring... [Pg.20]

Since perfect knowledge of the model is rarely a reasonable assumption, soft computing methods, integrating quantitative and qualitative modeling information, have been developed to improve the performance of observer-based schemes for uncertain systems [36], Major contributions to observer-based approaches can be found in [39, 56] as well, where fault isolation is achieved via a bank of observers, while identification is based on the adoption of online universal interpolators (e.g., ANNs whose weights are updated on line). As for the use of observers in the presence of advanced control techniques, such as MPC or FLC, in [44] an unknown input observer is adopted in conjunction with an MPC scheme. [Pg.125]

We showed through nonlinear dynamic simulations how the process reacts to various disturbances and changes in operating conditions. We have not shown any attempts to optimize process performance, to improve the process design, or to apply any advanced control techniques (model-based, nonlinear, feedforward, valve-position, etc.). These would be the natural next steps after the base-level regulatory control system had been developed to keep the process at a stable desired operating point. [Pg.355]

Using advanced control techniques to improve the stability and performance of nuclear power station boiler, IFAC 10th World Congress, Munich, Germany, July. [Pg.307]

The importance of the digital computers for the present and future implementation of advanced control techniques... [Pg.384]

Through the ACT documents, EPA provides information on the full range of NO, control technologies for categories of stationary sources that emit or have the potential to emit 25 tons per year or more of NO,. While the ACT documents will not contain presumptive RACT, they will contain extensive background information on control technologies, costs, etc., that can be used by States in making RACT determinations. Further, the ACTs can be used to identify advance control techniques that may be needed in a SIP attainment demonstration. [Pg.26]

Models are useful for optimal sensor selection and testing, sensor location, filtering and inference of unmeasured properties and process control. The trends nowadays in process control are toward model-based control, and, as the term signifies, application of advanced control techniques may not be possible without a model. [Pg.171]

The phenomenon of continuous oscillation has been attributed to the intermittent particle generation coupled with a slow washout, as described previously. The application of advanced control techniques to stabilize these oscillations has met with limited success [17,41,42] and it has been shown that the use of a plug flow reactor (PFR) as the first reactor will stabilize the system. All particle nucleation takes place in the PFR. Subsequent growth of the particles takes place in the downstream CSTRs. The segregation of particle nucleation and growth prevents the onset of oscillation. [Pg.189]

Feedback Control Systems Advanced Control Techniques... [Pg.1915]

There are also new balancing techniques used in the process control (dynamic balances, instrumentation design and maintenance, etc.). Advanced control techniques incorporated in process computers are very often based not only on directly measured variables but also on secondary variables calculated from balance models. [Pg.2]


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Advanced techniques

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