Product design problem

Process design can be considered as an internal sub-problem of the total product design problem in the sense that once the identity of the chemical product has been established, the process and/or the sequence of operations that can produce it, needs to be determined. 

These product design problems are typically formulated as,... 

Six chemical product design problems are presented together with the solutions developed by students from the University of Minnesota. These problems cover the following topics... 

As noted above, the original product design problem was to formulate a cleansing bar that did not leave a bathtub ring. In addition to this primary attribute, however, the product had to be generally recognizable as a high qual-... 

As mentioned, chemical product design requirements can come about because of desires for a totally new product, complaints about the functionality of existing products, and/or the failure due to malfunctions of existing products. Therefore, there are several kinds of chemical product design problems. For instance those ruled by structural decisions, those ran by functional decisions and those that depend on both factors. Let us consider the design of perfumes to explain theses cases. 

L. Constantine, K. Bagherpour, R. Gani, J.A. Klein D.T. Wu, 1996, Computer Aided product design Problem formulations, methodology and applications, Computers Chemical Engineering, 20 (6/7), 685-702. 

As the limitations of the additive group-contribution techniques become more apparent, new representational models will be required to solve the product design problem. These models must maintain some simplicity in the structure-property relationships, which can be inverted in an efficient and explicit manner to yield the structure(s) of the feasible molecule(s). Such models have yet to be invented, but it is important to keep in mind the needs of the product design, as new theories and techniques are being written for the estimation of physical properties. 

Constantinou, L., Gani, R., Fredenslund, Aa., Klein, J. A., and Wu, D. J., Computer-aided product design, problem formulation and application. Proc. PSE 94, Kyongju, Korea (1994). 

In Ref. the authors have applied NN to predict the molecular surface of the acid, reactive and direct dyes. The mapping of the three-dimensional molecular surfaces into Kohonen network enabling the prediction of substantivity is an example of the direct formulation of the product design problem. 

By decoupling the constitutive equations from the balance and constraint equations the conventional process/product design problems may be reformulated as two reverse... 

For heterogeneous catalysts, tandem reactor technology also relies on the fact that each polymer particle is in fact a microreactor operated in semibatch mode, into which monomers and chain-transfer agents are fed continually, while the polymer formed never leaves the microreactor. In this way, polymer populations with different average properties are produced in each reactor and accumulate in the polymer particle microreactor, as illustrated in Figure 8.37. In theory, an optimal balance does exist between the fractions of these different populations to meet certain performance criteria. This creates a truly fascinating reactor and product design problem because the fractions of the different polymer populations per particle will be a function of the residence time distribution in the individual reactors in the reactor train. 

Figure 11.3 Procedure for solving a muiti-objective chemica product design problem...

Note that the procedure is designed specifically for product design problem where different classes of property prediction models are used and the molecular structure of the product is represented by using molecular signature descriptors. The detail of each step is discussed as follows. 

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