Case studies results

At times, it is possible to build an empirical mathematical model of a process in the form of equations involving all the key variables that enter into the optimisation problem. Such an empirical model may be made from operating plant data or from the case study results of a simulator, in which case the resultant model would be a model of a model. Practically all of the optimisation techniques described can then be appHed to this empirical model. 

Subj ects have included almost the full range of possible topics. In each case study, results have been pepared as a formal Environmental Science and Engineering report. A list of reports and sponsoring organizations is included as an appendix. 

Burke JM, Zufall MJ, Ozkaynak H (2001) A population exposure model for particulate matter case study results for PM2.5 in Philadelphia, PA. J Expo Anal Environ Epidemiol 11 470-489... 

In Section 8.4 we discussed decomposition-based HEN synthesis approaches that feature three separate tasks to be performed sequentially (i) minimum utility cost, (ii) minimum number of matches, and (iii) minimum investment cost network configuration. Such a decomposition was motivated by the discovery of the pinch point on the one hand and by our inability in the 1980 s to address the HEN synthesis problem as a single task problem. Application of such sequential synthesis approaches in many case studies resulted in good quality networks with respect to the total annualized cost which is a strong indication of the clever decomposition scheme. 

Dense membrane reactors are discussed, emphasizing the most frequently investigated configurations and applications. Factors influencing economics are analyzed and, as a case study, results on the water-gas shift reaction in Pd-based membrane reactors are presented. 

In each section, we briefly summarize relevant experiences from the three case studies, discuss whether similar developments are taking place in the U.S. nuclear power industry, and evaluate the implications of the case studies with regard to safety in the U.S. nuclear power industry. Thus, this chapter is intended to synthesize the results of the case studies and assess their relevance to the U.S. nuclear power industry, rather than providing a comprehensive summary of all case study results. 

Recycling in textiles Table 5.8 Case study results... 

The next sections present complexities of FSCN (section 3), and the classification of logistics activities (section 4). Section 5 introduces several outsourcing approaches. Case study results are presented in the section 6. In section 7 and 8, results are analyzed and theoretical and empirical insights are discussed. The paper concludes with a summary of our main findings and suggestions... 

Figure 9. Aspen Hydocracker case study results hydrogen consumption and weighted average reactor temperature (WART) versus product sulfur content.

The concentration profiles that result from solving the methane and the higher hydrocarbon reaction rates simultaneously agree well with the profiles reported by others, and the reactor effluent species concentrations agree well with those observed fi om industrial reformers (Appendix A). The effluent concentrations are fairly insensitive to reaction rates, since industrial reformers operate near equilibrium conditions. Effluent conditions will only be noticeably affected by reaction rates as the catalyst activity declines significantly. The temperature profile, especially in the first on third of the reactor which is furthest from equilibrium, is affected significantly by reaction rates, and therefore is the most affected by the catalyst activity. The case study results in Appendix B illustrate the concentration profiles, and the effects of catalyst activity on temperature profiles. 

As an illustration. Figure 12 shows case-study results from a rigorous model for a two-reactor hydrocracker with partial recycle of unconverted oil. The unit runs at about 60% conversion-per-pass. A fixed flow of unconverted bottoms is recycled. The remainder is exported to the FCC unit or heavy diesel blending. At present, the export comprises about half of the total unconverted oil. 

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