ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
In this study, optimal temperature profiles (or histories),T(t), are obtained for nonvaporizing plug-flow (or batch) Nylon 6 reactors using the minimum principle. Two objective functions are studied, one in which the monomer conversion, convtf, is maximized, and the other in which the undesirable side product (cyclic dimer) concentration in the output stream, [C2]tf, is minimized. The control variable, temperature, is constrained to lie between 220°C and 270°C in order to ensure single phase polymerization. The most significant difference between this study and earlier ones is that the residence (or reaction), time tf, is not specified a priori, but is determined optimally by the use of a ‘stopping’ condition such that the polymer product has a number-average chain length, μn, equal to some desired value μn.d. Simultaneously, an end-point constraint is used, which, depending on the objective function used, forces either the cyclic dimer concentration or the monomer conversion at the end of the reactor to lie at a specified value, [C2]d or convd. Thus, this algorithm incorporates stopping conditions as well as end-point constraints and so is more complex than earlier ones, but the results are more meaningful. Different nonisothermal optimal temperature profiles are obtained for the two objective functions studied, depending on the values of μn.d, convd, [C2]d, and the feed water concentration, representing the complex interplay of several opposing factors.
Additional Material:
13 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760261503
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