Retrofit design sustainability

The review paper by Barbosa-Pdvoa (2007) covered various approaches for both design and retrofit design problems. It is noteworthy that the approaches reported to the date of this publication took into account only retrofitting analysis regarding the scheduling of batch operations, and Barbosa-Pdvoa (2007) did not consider the benefits that can be achieved in terms of sustainable design. 

Strategic Sustainable Assessment of Retrofit Design for Process Performance Evaluation... 

This chapter is organized as follows. In section State of the Art an overview of the state of the art on sustainable retrofit design tools and metrics is presented. In section Framework for Assessment of Retrofit Design Alternatives the strategic sustainable assessment of retrofit design (SARD) framework is presented with a step-by-step description. A case study is presented in section Case Study p-Galactosidase Production to highhght the application of the framework. Finally, conclusions are drawn in section Conclusions. 

Section Sustainabihty in Retrofit Design imderpins the importance of sustainability in the emerging theme of sustainable in retrofit design. Then a literature review on the areas of assessment required for retrofit design, which cover the three pillars of sustainabihty (sections Economic PiUar, Environmental Pillar, and Social Pillar), will be presented. 

For the retrofit action, which does not affect the external stakeholders, the process assessment area is the most suitable boundary for sustainability analysis (Fig. 11.2). In the process assessment, the areas of improvement are the traditional economic indicators applied to retrofit design analysis. The operational results as well as the investment analysis of the proposed retrofit designs are accounted for. The operational results are the traditional indicators applied by engineers in retrofit design assessment [12]. They should be always contemplated, since after the implementation of a retrofit design those costs are going to be incurred at least for the next 5 years (minimum lifetime for a project). Regarding the operational results, several authors point out different aspects that should... 

Level I Quick sustainable operation decisions This assessment employs the most basic analysis of the retrofit design assessment. It requires less data and time to analyze the retrofit alternatives however, it aggregates data and it does not include several aspects that could be important for the analysis. It wiU avoid possible tradeoffs that occur in more complex analyses nonetheless, these tradeoffs might be important to achieve more sustained decisions. 

Level II Sustainable operation decisions The analysis performed at this level employs more precise methods, which focus on the implications of retrofit designs at the process level. This level gives a grounded process analysis and deeply studies the sustainability of the proposed retrofit actions. This analysis is more intensive data, since it requires more input information, therefore the time for the analysis will be longer than for Level I. Possible tradeoffs and critical decisions will be exposed through this analysis. Companies undertaking this type of analysis are aware of the importance of sustainability and they want to consider sustainability in their daily decisions. 

Level III Sustainable supply chain decisions The highest level of analysis considers the retrofit designs integrated in the whole system. This level of analysis represents a holistic view and it is intended for companies aiming to achieve sustainable supply chains. This analysis requires time and it is data intensive. It covers several aspects of the process and assesses the relationship between stakeholders. Decisions wiU include conflicting aspects, which should be weighted, so that a final decision can be achieved. 

Figure 11.8 Strategic radar for reporting sustainable retrofit design decisions.

Since both retrofit actions can be considered together, the decision maker can opt to perform a Level II economic analysis, since it is required for the botdeneck of scale and it fits the raw material consumption bottleneck analysis. For the environmental and social pillars, the Level I will be conducted, since it is enough for a sustained assessment of both retrofit designs. 

In this case, a Level I analysis has been performed for environmental and social aspects and a Level II analysis has been performed for economic aspects. This radar chart indicates that this company is not following a sustainable strategy, but it is already considering at a basic level the influence of sustainability issues in the retrofit design. 

Carvalho, A., Gani, R., and Matos, H. (2008) Design of sustainable chemical processes systematic retrofit analysis generation and evaluation of alternatives. Process Safety and Environment Protection, 86, 328-346. 

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