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Process Control Systems Episode 8

Tham khảo tài liệu 'process control systems episode 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Multivariable Process Control I PO3 2. Shinskey F. G. Analog Computing Control for On-line Applications Control Eng. November 1962. 3. Roos N. H. Level Measurement in Pressurized Vessels ISA Journal May 1963. 4. Bristol E. H. On a New Measure of Interaction for Multivariable Process Control Trans. IEEE January 1966. 5. Dwyer P. S. Linear Computation chap. 13 John Wiley Sons Inc. New York 1951. PROBLEMS 7.1 Classify the five controlled variables appearing at the beginning of the section Decoupling Control Systems. If the composition of only one product needed to be controlled what could be done with the manipulated variable 7.2 Two liquids are mixed to a controlled density and total flow. Construct a relative-gain matrix for the system using rn and to represent the manipulated flows of streams whose densities are p and p2 let F be total flow and p the density of the blend. Assume that the volumes are additive. 7.3 The density loop in the previous example oscillates with a period while that of the flow loop is 4 sec. Design a decoupling system for the process. 7.4 In a given distillation column a 1 percent increase in distillate flow D causes distillate composition y to decrease by 0.8 percent and bottoms composition to decrease by 1.1 percent. Under the same conditions a 1 percent increase in steam flow Q causes y to increase by 0.3 percent and to decrease by 0.2 percent. Calculate the relative-gain matrix. 7.5 It is desired to control both the temperature T and the pressure P in a chemical reactor by manipulating coolant temperature and reagent flow F. It seems that at constant flow is 1.0 and that is 0.4 at constant is and is 4.8 Select the best pairs for control loops. 7.6 Prove that a relative-gain matrix may be prepared from inverted closed-loop gains as well as open-loop gains as described in the paragraph following Eq. 7.13 . Illustrate this with the 2 by 2 matrix given in Eq. 7.16 . Feedforward Control CHAPTER it has been shown that the nature of the process