Process Integration Using Block Superstructure

Abstract

We propose a general mathematical model for various process integration problems, involving mass integration, heat integration, simultaneous mass and heat integration, and property integration. The process units, including regenerators/interceptors, mixers, and splitters are represented using blocks. The blocks are arranged in a two-dimensional grid, and the arrangement of these blocks gives rise to various process integration networks. The existence of connecting streams between adjacent blocks and jump flows among all blocks enables the necessary interaction between different blocks via material and energy flows. The size of the block superstructure is determined by the number of layers with mixing operations, process units, product streams, and heat integration stages. The general process integration model is formulated as a mixed-integer nonlinear optimization (MINLP) problem with the minimization of total annual cost as the objective. We demonstrate our approach using four case studies from the process integration literature.

Building Block-Based Synthesis and Intensification of Work-Heat Exchanger Networks (WHENS)

“…The new representation is based on the concept of "abstract building blocks" originally proposed by Hasan and co-workers for general process design, integration and intensification [37][38][39]. Each building block has two fundamental design elements.…”

“…Superstructure provides an excellent means to automatically generate many network configurations, but the traditional superstructures could still miss innovative solutions due to a lack of representation. To this end, Hasan and co-workers have recently put forward a novel superstructure representation using abstract building blocks for systematic process synthesis and intensification [37][38][39][40]. With a generic block representation, there is no need to pre-specify the stream and equipment identities and flowsheet configurations.…”

Process synthesis using block superstructure with automated flowsheet generation and optimization

“…Although many alternatives are embedded in the block superstructure and additional connections can be formed to connect nonadjacent blocks by transferring materials through empty blocks (i.e., blocks with no equipment assignment), the number of process configurations may be limited if each block interact with only four adjacent blocks. Hence, additional connections between nonadjacent blocks are considered through “jump flows.” We use to designate the flow rate of the component k in a jump flow from block B i , j to . With this representation, many different synthesis problems can be addressed.…”

“…Process synthesis utilizes available raw materials and identifies unit operations and their interconnections to generate desired products with the goal of optimizing various objectives under several design constraints . New trends in process synthesis highlight the importance of process intensification and sustainable systems design . The methods for process synthesis can be classified as knowledge‐based and optimization‐based methods .…”

“…These building blocks decompose classical unit operations into different phenomena, emulate these phenomena, and generate new and intensified designs of unit operations, equipment, and process flowsheets through recombination. The block‐based representation is recently extended to incorporate process integration problems …”