Cost optimization

It might be possible to reduce the inventory significantly by changing reactor conversion and recycle inert concentration without a large cost penalty if the cost optimization profiles are fairly flat. 

Gundersen, T., and Naess, L., The Synthesis of Cost Optimal Heat Exclumger Networks An Industrial Review of the State of the Art, Computers Chem. Eng., 12 503, 1988. 

The U.S. chemical industry achieved an annual reduction of 4.2% in energy input per unit of output for the period 1975—1985 (2). This higher reduction resulted from cost optimization, the tradeoff of increased capital for reduced energy use, that was driven by energy prices (4). In contrast, from 1985 to 1990, the energy input per unit of output has been almost flat (2) as a consequence of falling prices. The average price the U.S. chemical industry paid for natural gas fell by one-third between 1985 and 1988 (1,5). 

Batch readers—optimum residence time for series and complex reactions, minimum cost, optimal operating temperature, and maximum rate of reaction... 

This interplay of the many variables is extremely complex and involves a matrix of the many variables. As an example in the molding simulation TMconcept system programmed Molding Cost Optimization (MCO) of Plastics Computer Inc., Dallas, TX, there are well over 300 variables. It is not reasonable to expect a person using manual methods to calculate these complex interactions even if molding only a modest shaped product without omissions or errors. Computerized process simulation is a practical tool to monitor the influence of design alternatives on the processability of the product and to select molding conditions that ensure the required product quality (3). 

Studies on the detergency performance and cost optimization of the LAS/AS/ AES have been published [42,43]. Figure 19 shows the performance optimization on sebum soil on cotton cloth and a cotton/polyester permanent press cloth. 

The overall cost optimization criterion (5.4-137) to be minimized is composed of two terms. The first, which is called proportional, is related to the yield of both C and E one needs to maximize the yield of C, Yc, while minimising the ratio of yields, Y c. Yc and Kg are nc.f/nB.o and nE./nBA, respectively, n is number of moles, and y is a factor expressing the relative weight of the two terms (y was assumed to be one). The second term, called the non-proportional or fixed cost of operation, is the reciprocal of the ratio of yield of C per batch time, s, and as such it should be minimized, p is the weighing factor (equal to 174 in the process under consideration) in this term. 

Thus the hot and cold utility consumption both need to be increased by 1.6 MW to restore the Arm to the original 10°C. In fact there is no justification to restore the Arm back to the original 10°C. The amount of additional energy shifted along the utility path is a degree of freedom that should be set by cost optimization. However, the example illustrates how the degrees of freedom can be manipulated in network optimization. 

The objective of the present study is to develop a cross-flow filtration module operated under low transmembrane pressure drop that can result in high permeate flux, and also to demonstrate the efficient use of such a module to continuously separate wax from ultrafine iron catalyst particles from simulated FTS catalyst/ wax slurry products from an SBCR pilot plant unit. An important goal of this research was to monitor and record cross-flow flux measurements over a longterm time-on-stream (TOS) period (500+ h). Two types (active and passive) of permeate flux maintenance procedures were developed and tested during this study. Depending on the efficiency of different flux maintenance or filter media cleaning procedures employed over the long-term test to stabilize the flux over time, the most efficient procedure can be selected for further development and cost optimization. The effect of mono-olefins and aliphatic alcohols on permeate flux and on the efficiency of the filter membrane for catalyst/wax separation was also studied. 

In the context of reachability analysis, this graph is called symbolic reachability graph of the automaton A and can be searched using shortest path search techniques as widely used in computer science. Hence, the task of finding the cost-optimal schedule is to find the shortest (or cheapest) path in a (priced) symbolic reachability graph. 

Behrmann, G., Fehnker, A., Hune, T.S., et al. (2001) Efficient Guiding Towards Cost-Optimality in Uppaal. Proceedings of TACAS 01, Springer, London, pp. 174-188. 

E., et al. (2001) As Cheap as Possible Efficient Cost-Optimal Reachability for Priced Timed Automata. Proceedings of CAV 01, vol. 2102 of LNCS, Springer, Berlin, pp. 493-505. 

Melius Guiding and Cost-Optimality in Model Checking of Timed and Hybrid Systems. Dissertation, KU Nijmegen. 

Major equipment estimates based on a more detailed given flowsheet that includes all of the equipment of significance roughly sized with approximate costs. Optimization using process flow simulators (refer to Chapter 15) can be employed. Figure B.2 illustrates a typical analysis for a tank. Refer to Brown (2000) for additional details. 

Trimmel, M. L., Winegardner, D. L., and Testa, S. M., 1989, Cost Optimization of Free Phase Liquid Hydrocarbon Recovery Systems In Proceedings of the Hazardous Materials Control Research Institute Conference on Hazardous Waste and Hazardous Materials, April. 

The cost of a vertical Lasagna system was evaluated by DuPont using a cost optimization model. For remediation of TCE to a depth of 40 to 50 ft (12 to 15 m) in clay on a 1-acre (4047-m ) site, costs were estimated to range from 40 to 90/yd ( 52 to 117/m ). Soil properties, depth of contamination, cost of emplacing electrodes and treatment zones, required purge water volume, cleanup time, and cost of electrical power were all included in the estimate (D12500Y, p. 10). 

The trend is toward friendly, increasingly miniaturized instruments that can produce efficient and selective separations. Many instruments are controlled by insertable PC cards so the analyst can automatically set up the desired procedure. Moreover, diagnostic software is helping the user to identify failures. Costs are minimized, especially solvent costs. Optimization procedures currently in use save time (and time is money). Methods and instruments are validated for compliance with, for example, ISO recommendations. 

Given a number of input multicomponent streams which have specified amounts for each component, create a cost-optimal configuration of distillation columns, mixers, and splitters that produces a number of multicomponent products with specified composition of their components. 

The products feature components that exist in the input streams and can be obtained by redistributing the components existing in the input streams, while the cost-optimal configuration corresponds to the least total annual cost one. 

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