Intégration énergétique de procédés industriels par la méthode du pincement étendue aux facteurs exergétiques.
The pinch analysis method is a useful tool for the energy integration of industrial processes (structuring and simplification using simple guidelines). The pinch analysis method, extended to include exergy factors, falls within the framework of a global multidisciplinary analysis which considers in light of a sustainable development, economic, energetic, exergetic, and environmental factors. One of the essential themes of such a global framework is the system’s life cycle analysis. This analysis considers the manufacture, the exploitation and the recycling of components (from cradle to grave). Such considerations as well as pressure drops in heat exchangers were not included in the original pinch method, which centered primarly on economic and heat transfer aspects. The extension of the pinch analysis method to include exergy factors related to some of the considerations mentioned above, leads to a global exergy balance which includes irreversibility considerations due to heat transfer, dissipation and the manufacture of components. The thermodynamic optimisation of heat exchangers based on an optimal distibution of exergy losses is realized, and the grey exergy assiociated with the manufacture of shell and tube heat exchangers is calculated as an example. Further extension of the pinch method to include an electrical energy balance was also realized. Such a balance is particularly useful when intoducing heat pumps or power units. The extended composite curves which result from the extension above offer a graphic representation of all the exergy losses of the process using a Carnot factor versus heat rate diagram and an electric power versus Carnot factor diagram. With such diagrams, the choice of the optimal pinch value (Tmin) will be determined for the minimum total exergy loss of the process. The heat exchanger network design is also based on an exergetic criterion (the difference of global Carnot factor) which allows an exergetic optimisation of the position of the heat exchanger. A procedure for selecting the different heat exchanger alternatives is included in the proposed design method. This procedure limits the number of network designs having the best chances to arrive at the optimal network (network with the minimum global exergy losses). The extended pinch analysis method proposed here has been applied to typical industrial processes with acceptable, consistent and sometimes differents results from those obtained with the original pinch method. This enrichment of the method will lead to better designs.
Record created on 2005-08-08, modified on 2016-08-08