Eastman control structure

Jim Downs (1992) of Eastman Chemical Company has insightfully pointed out the importance of looking at the chemical component balances around the entire plant and checking to see that the control structure handles these component balances effectively. The concepts of overall component balances go back to our first course in chemical engineering, where we learned how to apply mass and energy balances to any system, microscopic or macroscopic. We did these balances for individual unit operations, for sections of a plant, and for entire processes. 

Several different control structures have been published in the literature for the Eastman process Ricker (1993), McAvoy and Ye (1994), Price et al. (1994), Lyman and Georgakis (.1995), Ricker and Lee (1995), Baneijee and Arkun (1995), Kanadibhotla and Riggs (1995), McAvoy... 

With four realistic case studies... Tennessee-Eastman, isomerization, vinyl acetate, and HDA processes (the first time a workable control structure for HDA has ever been published)... Plantwide Process Control gives chemical engineers, and students, the tools they need to design effective control schemes. 

Control Structure Selection for open loop unstable processes is the main theme of this paper. Hankel singular value has been used as a controllability measure for input-output selection. This method ensures feedback stability of the process with minimal control effort as well as it provides a quantitative justification for the controllability. Simulation results with Tennesse-Eastman test-bed problem justify the proposed theory. 

Several different control structures have been proposed for reactive distillation columns. The appropriate control structure depends on the flowsheet and on the type of reactions occurring in the column. If two reactants are involved and if it is desirable to operate the process without any excess of reactant, it is necessary to manage the fresh feedstreams so that the stoichiometry is exactly balanced. A composition analyzer that measures an internal composition in the column is sometimes required. However, if two produets are produced, it may be possible to avoid the use of an analyzer by using two temperatures in the column to adjust the two feedstreams. This type of strueture was proposed by Roat et al. for the ideal reaction A + B C + D in one of the earliest articles dealing with reactive distillation control. We call this control structure the Eastman stmcture. ... 

The chemistry of hydrolysis and condensation of silicon alkoxides is now understood in considerable detail, as indicated in the chapter by Coltrain and Kelts (Eastman Kodak Co.). Extensive use of nuclear magnetic resonance has revealed the influence of factors such as pH on the kinetics of the competing reactions. With this information it is possible to rationalize the structures of the aggregates, as revealed by studies of small-angle scattering of X-rays and neutrons. This level of understanding opens the possibility for deliberate control of gel structure and properties. Nonsilicate systems have received less... 

There are only a handful of investigations of aging of materials at the nanometer size scale. The earliest was done by the author in collaboration with workers at Eastman Kodak in a structural recovery investigation of o-TP confined in controlled pore glasses having a variety of pore sizes [McKenna et al., 1992], This work is of interest because of the errors of interpretation made in that study. The... 

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