Distillation control

P. S. Buckley, W. L. Luyben, andj. P. Shunta, Design of Distillation Control Sjstems, Instmment Society of America, Research Triangle Park, N.C., 1985. 

Hill, New York, 1988. Liiyben, Practical Distillation Control, Van Nostrand Reinliold, New York, 1992. 

SHINSKEY, F. G. (1976) Chem. Eng. Prog. 72 (May) 73. Energy-conserving control systems for distillation units. SHINSKEY, F. G. (1984) Distillation Control, 2nd edn (McGraw-Hill). 

Buckley, P.S. Some Practical Aspects of Distillation Control, paper presented at Chemical Engineering Seminar, Ohio University, Nov. 20, 1967. 

K.E. Haggblom and K.V. Waller. Practiced Distillation Control, chapter Control Structures, Consistency, and Transformations. Van Nostrand Reinhold, New York, 1992. 

F.G. Shinskey, Distillation Control, McGraw-Hill, New York, 1984. 

Gokhale, V. Hurowitz, S. Riggs, J.B. A comparison of advanced distillation control techniques for a propane/propene splitter. Ind. Eng. Chem. Res. 1995, 34, 4413-4419. 

Implementation of MPC For a new MPC application, a cost/benefit analysis is usually performed prior to project approval. Then the steps involved in the implementation of MPC can be summarized as follows (Hokanson and Gerstle, Dynamic Matrix Control Multivariable Controllers, in Practical Distillation Control, Luyben (ed.), Van Nostrand Reinhold, New York, 1992, p. 248 Qin and Badg-well, Control Ene. Practice, 11 773, 2003). 

McAvoy, T. J., "Steady State Decoupling Sensitivity with Application to Distillation Control," AIChE National Meeting Houston, Texas, April, 1979. 

Fig. 8.1 Laser distillation control scenario discussed in detail in Section 8.3. Two ljtsfi with pulse envelopes ,(0 and e2(0 couple, by virtue of the dipole operator, the states and L enantiomers to two vibrotational states 1) and 2) (denoted If ,) and E2) in the.t i the excited electronic manifold. A third laser pulse with envelope r.0(i) couples the ex E)) and E2) states to one another. The system is allowed to absorb a photon and relax hack the ground state. After many such excitation-relaxation cycles, a significant cnantionneh excess is obtained, as explained in Section 8.3. ...

Shlnskey, F. G., Distillation Control for Productivity and Energy Conservation, Chapters 6 and 7, McGraw-Hill, NY (1977). 

Downs, J. J. Distillation Control in a Plantwide Control Environment, Chap. 20 in Practical Distillation Control, W. L. Luyben (ed,). New York Van Nostrand Reinhold (1992). 

More work has appeared in the chemical engineering literature on distillation column control than on any other unit operation. Books on this important subject date back to the pioneering work of Rademaker et al. (1975), Shinskev (1977), and Buckley et al. (1985). Some of the more recent developments are discussed in Luyben (1992). The longterm popularity of distillation control is clear evidence that this is a very important and challenging area of process control. Most chemical plants and all petroleum refineries use distillation columns to separate chemical components. Distillation is the undisputed king of the separation processes. 

We cannot hope to cover the vast subject of distillation fundamentals and control in a single chapter in this book. Our objective here is to review some of the basic principles about distillation and then to summarize the essentials of distillation column control, particularly as it relates to the plantwide control problem. Many more details are available in the books cited above. In the first section we review some of the important fundamentals about distillation. Sections 6.3 through 6.8 discuss distillation column control mostly from the perspective of an isolated column or column system, This treatment presents what may appear to be a laundry list of control structures for different types of columns. Although we feel this presentation is valuable, particularly for the young inexperienced student or engineer, it is also vital to retain a broader plantwide perspective. Section 6.9 addresses some of these plantwide distillation control issues. In the next section we review the process fundamentals of distillation as they relate to process operation and control. 

In this section we discuss some basic concepts concerning distillation control degrees of freedom, basic manipulated variables, and constraints. 

In this chapter we have presented some fundamental concepts of distillation control. Distillation columns are without question the most widely used unit operation for separation in the chemical industry. Most final products are produced from one end or the other of a distillation column, so tight control of product quality requires an effective control system for the column. However, the column is usually an integral part of an entire plant, so its control scheme must also be consistent with the plantwide control structure. 

Keywords distillation control, neurofuzzy networks, soft sensors, genetic algorithms... 

H. Leegwater. Industrial experience with double quality control. In W. L. Luyben (Ed.), Practical distillation control. New York, USA Van Nostrand Reinhold, 1992. 

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