Distillation Fundamentals

Lockett, M. J. Distillation Fundamentals (Cambridge University Press, 1986). 

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. 

Gorak, A. and Sorensen, E. (2014) Distillation Fundamentals and Principles, Elsevier, Oxford, UK. 

Distillation fundamentals do not change, nor does the importance of distillation in our energy-intensive society. What does change is the range of applications and methods of analysis that provide more insight and offer improvements in steady-state design and dynamic control. In the seven years since the first edition was published, a number of new concepts and applications have been developed and published in the literature. 

F. Generalize. This type of procedure can be applied to many multiconponent distillation problems. It is more common to specify fractional recoveries rather than concentrations because it is more convenient. Note that it is inportant to not make specifications that violate material balances and distillation fundamentals (e.g., 99.4% recovery of C4 in the distillate and 90% mole fraction of C5 in the bottoms). 

Distillation has been practiced in one form or another for centuries. It was of fundamental importance to the alchemists and was in use weU before the time of Christ. The historical development of distillation has been pubHshed (1) as has the history of vapor—Hquid contacting devices (2). 

C. D. HoUand, Fundamentals of Multicomponent Distillation, McGraw-HiU Book Co., Inc., New York, 1981. 

A third fundamental type of laboratory distillation, which is the most tedious to perform of the three types of laboratory distillations, is equilibrium-flash distillation (EFV), for which no standard test exists. The sample is heated in such a manner that the total vapor produced remains in contact with the total remaining liquid until the desired temperature is reached at a set pressure. The volume percent vaporized at these conditions is recorded. To determine the complete flash curve, a series of runs at a fixed pressure is conducted over a range of temperature sufficient to cover the range of vaporization from 0 to 100 percent. As seen in Fig. 13-84, the component separation achieved by an EFV distillation is much less than by the ASTM or TBP distillation tests. The initial and final EFN- points are the bubble point and the dew point respectively of the sample. If desired, EFN- curves can be established at a series of pressures. 

Freudenberg has obtained one nitrogen-free product, C13H24O, b.p. 215-220°, by the distillation of aconitine or amorphous aconitine with barium hydroxide or zinc dust. He suggests that the fundamental hydrocarbon, C20H33, may contain two five-membered and four six-membered rings, which will include nine secondary carbon atoms. 

Fluid catalytic cracking is one of the most important conversion processes in a petroleum refinery. The process incorporates most phases of chemical engineering fundamentals, such as fluidization, heat/mass transfer, and distillation. The heart of the process is the reactor-regenerator, where most of the innovations have occurred since 1942. 

One particularly important case of distillation sequencing is worthy of special consideration. This is the case of crude oil distillation, which is the fundamental process underlying the petroleum and petrochemicals industry. Crude oil is an extremely complex mixture of hydrocarbons... 

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