A Modular Approach to Sustainability Assessment and Decision Support in Chemical Process Design

Selection of sustainable process design at early design stage is important to minimize long term effect to the environment and future generations. In the chemical industry, process design sustainability, in terms of energy and material use efficiency, waste minimization, process and product life cycle performance, total cost accounting, etc, is of upmost importance. Over the past decade, a variety of sustainability indicators have been introduced, but with various challenges. It becomes clear that the industry needs urgently practical tools that can be used to conduct convincing systematic sustainability assessment on existing processes and/or new designs, and further to obtain decision support for necessary process modification or selection of design alternatives. This work presents a systematic modular approach for sustainability assessment and selection of process designs through integrating hard (quantitative) economic and environmental criteria along with soft (qualitative) quality criteria into the activities. The approach contains four modules: 1) a process simulator module, 2) an equipment and inventory acquisition (EIA) module, 3) a sustainability assessment (SA) module, and 4) a decision support process (DPS) module. The modules fully utilize the capabilities of process simulators and third party software, such that case model development, problem definition and formulation, data acquisition and analysis, and decision support, that are systematically integrated. The approach can facilitate process designers and decision makers significantly in conducting structured and accurate design assessment and deriving design decisions at early design stage. The functionality of the introduced approach is illustrated by an example of biodiesel process design. Insightful sustainability analysis and persuasive decision support in this case study demonstrate its superiority over commonly practiced techno-economy evaluation approaches.