Process Design: Integration vs Resilience
Ákos Orosza, Jean Pimentelb, Ferenc Friedlerc
aUniversity of Pannonia, Egyetem u. 10., H-8200 Veszprém, Hungary
bBudapest University of Technology and Economics, H-1111 Budapest, Hungary
cSzéchenyi István University, Egyetem tér 1., H-9026 Győr, Hungary
Process integration is a key component of process design, it reduces e.g., the energy and raw material consumptions and, therefore, improves the sustainability indicator of the process. In return the network of the processing system may become highly interconnected. Consequently, the failure of any step in the processing system may result in the failure of the whole system. Thus, the resilience of the system is not independent of the level of integration, higher level integration may reduce the resilience of the overall system. If the resilience of the processing system is important in process operation, it is to be considered during the process design.
In the current work, a general formulation for determining the resilience of a processing system has been developed. This formulation is general, there is no limitation on the structure of the processing system (e.g., on the number of loops, raw materials, and products) and on the types of the operating units. The algorithm for the determination of the resilience indicator of a processing system is based on the P-graph framework.
The interdependence of the process integration and resilience has been evaluated by solving an industrial process synthesis problem. On the basis of the P-graph synthesis algorithm, all feasible process structures have been generated and evaluated for both the resilience indicator and the level of heat integration. This case study illustrated that the reduction of the resilience indicator as the result of higher level of process integration can be compensated by higher level systems redundancy. Consequently, all benefits of process integration can be preserved even under strict systems resilience requirement by an additional investment.