Assessing Configuration Alternatives

Extensions to incorporate effects of taxation, an explicit modeling of product-mix effects (economies of scale and scope), make or buy/vendor selection and additional elements of technical capacity such as shared resources are provided in Chapter 3.4.3 to allow for an application to value chains with characteristics that differ from those that were considered when developing the model. 

Chapter 3.5 provides the results of numerical performance tests conducted which demonstrate that, despite its complexity, the resulting MILP model can be solved in reasonable time using the standard optimization software ILOG CPLEX 10. 

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In a deterministic planning environment the most likely scenario, here scenario 2, would be considered the base case and the optimization model would be solved based on this scenario. The optimal decision would be to open facility 1 in period 1 and facility 3 in period 2 leading to a total profit of 2,590. To assess the robustness of this network to alternative demand scenarios the profit achievable with this configuration in case of the alternative demand scenarios can be assessed. In the example, for scenario 1 the overall profit would be 1,640 and for scenario 3, 2,765 respectively. Considered individually, the optimal decision for scenario 1 would be to open only facility 1 with a total profit of 1,880 and for scenario 3 to open both facilities 1 and 2 in period 1 with a total profit of 2,931. In order to explicitly incorporate the uncertainties caused by the different realization probabilities of the three demand scenarios, the optimization model can be extended into a two-stage decision with recourse ... 

From the view point of the assessment, the quality of an HPLC separation in response to changes in different system variables, such as the stationary phase particle diameter, the column configuration, the flow rate, or mobile phase composition, or alternatively, changes in a solute variable such as the molecular size, net charge, charge anisotropy, or hydrophobic cluster distribution of a protein, can be based on evaluation of the system peak capacity (PC) in the analytical modes of HPLC separations and the system productivity (Peff) parameters in terms of bioactive mass recovered throughput per unit time at a specified purity level and operational cost structure. The system peak capacity PC depends on the relative selectivity and the bandwidth, and can be defined as... 

A mathematical development of the gasification system is in progress. Also an environmental assessment of the configuration continues. The primary stream of concern is the pyrolysis reactor scrubber liquid discharge. The thrust here is to characterize the stream and hopefully minimize formation of any contaminates in the pyrolysis step. Alternatively, a water cleanup steam would have to be incorporated. 

The enterprise utilizes the results of trade-off analyses and risk-reduction planning information to recommend a preferred alternative to the decision maker. The enterprise should assess the trade-off analysis to assure that the methodologies and data collection instrumentation were sufficient to support a fair and complete evaluation. Each recommendation should be presented in terms of configuration and cost, schedule, performance, and risk impact. 

Fuel forms. The three alternative fuel forms for an LS-VHTR have very different characteristics and different refueling strategies. Trade studies will be required to determine the optimum reactor core and fuel configuration. Our preliminary assessment suggests that both pebble bed and stringer-type cores would be easier and faster to refuel than the Fort St. Vrain prismatic cores. 

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