Solution of the Robust Model

Considering risk in terms of variations in both projected benefits and recourse variables provided a more robust analysis of the problem. As explained earlier, the problem will have a more robust solution as the results will remain close to optimal for all given scenarios through minimizing the variations of the projected benefit. On the other hand, the model will be more robust as minimizing the variations in the recourse variables leads to a model that is almost feasible for all the scenarios 

The results of the model considered in this Chapter under uncertainty and with risk consideration, as one can intuitively anticipate, yielded different petrochemical network configurations and plant capacities when compared to the deterministic model results. The concepts of EVPI and VSS were introduced and numerically illustrated. The stochastic model provided good results as the objective function value was not too far from the results obtained using the wait-and-see approach. Furthermore, the results in this Chapter showed that the final petrochemical network was more sensitive to variations in product prices than to variation in market demand and process yields when the values of 0i and 02 were selected to maintain the final petrochemical structure. 

Al-Sharrah, G.K., Hankinson, G., and Elkamel, A. (2006) Decision-making for petrochemical planning using multiobjective and strategic tools. Chemical Engineering Research and Design, 84 (All), 1019. 

(1982) Stochastic linear programs with fixed recourse. 

(1995) Models and model value in stochastic programming. Annals of Operations Research, 59, 1. 

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