Targeting safe-and-sustainable-by-design and circularity : a novel framework of waste-to-energy process assessment and optimization

Abstract

Municipal solid waste management has emerged as a critical issue. Waste-to-energy (WtE) is considered a promising approach to address improper waste disposal and energy shortage problems simultaneously. However, it is critical to recognize the lack of comprehensive evaluation frameworks for the complex WtE processes currently. In this work, a multidimensional framework called SSbDC-GA has been developed to evaluate and optimize WtE process in the conceptual stage. In the framework, a composite indicator called Safe and sustainable by design and circularity (CI-SSbDC), considering various indicators in the hazard, health, environment, circularity, and economic dimensions, has been applied. In addition, the genetic algorithm (GA) optimization has been used to obtain a higher CI-SSbDC value. A hazard and operability analysis (HAZOP) has been conducted to provide support to hazard dimension evaluation during operation. The case study aims to validate the adaptability and reliability of the proposed SSbDC-GA framework. In the base scenario with the scale of the plant was 1000 kg/h <inf>ELTs</inf>, the process showed promising profitability. The net present value, payback period, and internal rate of return were 20.51 M$, 7.5 years, and 16.61 %, respectively. The levelized cost of hydrogen was 3.13 $/kg. Parameter optimization has significantly promoted its scores for health and environmental dimensions. This study provided a generic framework that guides the design of the WtE process towards safety, sustainability, and circularity.