Towards Integrated Process and Control System Synthesis for Heat-Integrated Plants

Abstract

streams (where possible); in other words, a HEN should be designed for this process. Several techniques have been proposed for synthesis of HENs. Some of them are based on thermodynamic insights, such as those methodologies based on Pinch Analysis (Linnhoff and Hindmarsh, 1983;Linnhoff and Ahmad, 1990), and others are based on mathematical programming (Cerda and Westerberg, 1983;Floudas et al., 1986;Briones and Kokossis, 1999). Figure 2a shows the fl ow sheet for a heat integrated process, where a HEN was designed for the maximum energy Most chemical processes are networks of different pieces of equipment, as reactors, distillation columns, compressors, heat exchangers, etc. Process integration is an area of chemical engineering that deals with the optimal design of these networks, from the point of view of energy effi ciency, capital costs, emissions reduction, waster water minimization, and raw materials usage. Until recently, engineers developed conceptual process designs by experience and intuition, however, with the establishment of process integration methodologies, this activity can be performed systematically.One of the subjects that have received the most attention from researchers in this area is the steady state design of Heat Exchanger Networks (HENs). Several tools have been developed and are in use; however, the development of a tool for synthesis of HENs that takes into account network controllability is not available. Hence, the purpose of this paper is the development of a new methodology for design of heat-integrated chemical processes, particularly HENs where controllability and energy recovery are both balanced during the design synthesis stage.La plupart des procédés chimiques sont des réseaux de différentes pièces d'équipement, comme des réacteurs, des colonnes à distiller, des compresseurs, des échangeurs de chaleur, etc. L'intégration des procédés est un domaine du génie chimique qui s'occupe de la conception optimale de ces réseaux, en termes d'effi cacité énergétique, de coûts en capital, de réduction des émissions, de minimisation des eaux usées et de l'utilisation des matières premières. Jusqu'à récemment, les ingénieurs créaient des procédés conceptuels par expérience et intuition, mais avec la venue des méthodologies d'intégration des procédés, ce travail peut se faire de façon systématique. L'un des sujets qui depuis peu attire le plus l'attention des chercheurs dans ce domaine, c'est la conception à l'état stable de réseaux d'échangeurs de chaleur (HEN). Plusieurs outils ont été mis au point et sont employés : cependant, on n'a pas encore mis au point un outil pour la synthèse des HEN qui tienne compte de la contrôlabilité des réseaux. Ainsi, cet article vise à élaborer une nouvelle méthodologie pour la conception des procédés chimiques intégrés thermiquement, en particulier les HEN pour lesquels la contrôlabilité et la récupération d'énergie sont toutes deux équilibrées durant la phase de synthèse de la conception.

Process Design, Integration and Optimisation: Advantages, Challenges and Drivers

“…The former class of problems is illustrated by Li and Chang (2011), who proposed a systematic fl exibility assessment procedure to analyse and modify a given network so as to achieve the desired level of operational resiliency, and by Young et al (2006) who proposed a methodology for the design of heat-integrated chemical processes, particularly HENs, where controllability and energy recovery are both balanced during the design synthesis stage. The latter class of problems had been followed by Feng et al (2011b), who presented a methodology for a water allocation network design with process disturbance taken into account; the synthesised network structure can guarantee that the water system consumes minimum freshwater under both normal and disturbance conditions and with the minimum number of control streams under disturbance, and also, by Li and Chang (2011) who proposed a systematic fl exibility assessment procedure to analyse and modify a given network so as to achieve the desired level of operational resiliency.…”

Optimisation of petroleum refinery water network systems retrofit incorporating reuse, regeneration and recycle strategies

“…Other important recent work that has employed the optimisation approach to water network synthesis can be found in Pham et al (2009) and Karuppiah and Grossmann (2008). Another interesting line of related work employing the optimisation approach is in the process design of wastewater treatment technologies as found in Fels et al (1997) as well as a complete process plant (Young et al, 2006). The literature in WPA has been no less exciting with a well‐received recent review by Foo (2009) and recent work by his co‐workers in Ng et al (2010) and Tan et al (2009, 2010).…”