(752f) Intensification of Biorefinery Operations Using Building Blocks
Recently, a new method for systematic process intensification, which relies on building block-based representation of chemical process flowsheets, has been introduced . These building blocks can be integrated to form a two-dimensional grid embedding numerous non-trivial process alternatives [6-9]. Each block can be assigned with several physicochemical phenomena, e.g. reaction, vapor-Liquid equilibrium, solid-liquid equilibrium, etc., combination of which can yield various intensification pathways. In this work, we extend this novel representation methodology to various operations that take place in a biorefinery. Pulping which occurs in a pulp digester lies at the heart of a pulp mill and, here, we develop a new representation based on fundamental building blocks to represent the pulp digestion process. Mass transfer boundary layer is represented by the boundary shared by two neighboring blocks in different phases and digestion process is represented within the interior of the block. This building-block based representation is modeled using a mixed-integer nonlinear programming (MINLP) problem so as to minimize the energy consumption and increasing the yield of the process while searching for several intensified pathways. The proposed approach is demonstrated through several case studies focusing on the conventional Kraft pulping process, Kraft pulping process with pre-extraction of hemicellulose, Kraft pulping process with pre-extraction of hemicellulose and short fibers.
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