Process Life Cycle Assessment of supercritical CO2 dyeing: sustainability and feasibility evaluation

The textile industry is growing due to economic development and a rising global population, raising environmental concerns such as high energy and water use, water emissions, and chemical consumption. This master thesis reviews emerging textile production technologies that claim to be environmentally friendly and establishes criteria for assessing them. Specifically, it evaluates the environmental performance of supercritical CO2 (SC-CO2) dyeing compared to conventional dyeing. SC-CO2 dyeing technology & Seven criteria are developed for evaluating these technologies: environmental potential, technical quality, flexibility, technology readiness level (TRL), cost, resource availability, and interest. SC-CO2 dyeing is chosen for detailed evaluation. A Life Cycle Assessment (LCA) was conducted comparing SC-CO2 dyeing with conventional dyeing across four scenarios, using two electricity mixes and optimizing CO2 losses. Results show that SC-CO2 dyeing can be environmentally beneficial if optimized for CO2 emissions and energy use, and if greener electricity is used. However, electricity production remains a major impact factor. This thesis provides an initial assessment of SC-CO2 dyeing’s environmental performance and suggests that further research is needed to confirm its benefits for the textile industry.