Design cost-modeling

Figure 7.9 The Xp parameter avoids steep slopes on the Fp curves, whereas minimum Fp does not. (Reprinted from Ahmad, Linnhoff, and Smith, Cost Optimum Heat Exchanger Networks II. Targets and Design for Detailed Capital Cost Models, Computers Chem, Engg., 7 751, 1990 with permission from Elsevier Science, Ltd.)...

Dong, Z. 1997 Tolerance Synthesis by Manufacturing Cost Modeling and Design Optimization. In Zhang, H. (ed.). Advanced Tolerancing Techniques. NY Wiley Interscience. 

Ahmad S, Linnhoff B and Smith R (1990) Cost Optimum Heat Exchanger Networks II Targets and Design for Detailed Capital Cost Models, Comp Chem Eng, 7 751. 

In general, developing cost models of production system expansions only as a function of the unit flow rate does not provide a good capital cost estimate. For this reason, and as we mentioned earlier, our formulation only allowed the addition of predetermined capacities whose price can be acquired a priori through design companies quotations. 

The optimum number of plates, the optimum values of the decision variables for both outer and inner loop optimisation problems, and optimal amounts and composition of all products are shown in Table 7.2. Typical composition profiles in the product accumulator tank are shown in Figure 7.6. Bold faced mole fractions in Table 2 are the specifications (all satisfied) and underlined mole fractions are decision variables which were optimised. Although the optimum number of plates is almost close to that of the base case, the optimal total operation time is 14% lower than the base case. The profit with the optimal design and operation is 35% higher than that for the base case (calculated using the same cost model). This is obtained... 

Ernst et al.5 indicate that the Super Pro Designer contains models to help estimate the direct fixed capital cost based on 1995 dollars. These numbers may be suitably updated using the current CPI or other suitable index. Maintenance cost were set at 25% of the purchase cost of the equipment per year. Laboratory costs were allocated to capital costs. Labor costs were carefully calculated based on number of operator hours per equipment hour. This was done after analyzing scheduling of the entire process as well as noting that the operator time on each equipment was reasonable. 

In the near future, the main concerns of CAPE will probably focus on issues related to product design (molecular modeling for solving function-property-composition problems), supply chain management (cost reduction of raw materials, effective use of energy and its new sources), and life cycle assessment (mitigation of climate change, process sustainability). 

Forbes, J.F. Marlin, T.E. Design cost a systematic approach to technology selection for model-based real-time optimization systems. Comput. Chem. Eng. 1996, 20 (6/7), 717-734. 

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