Process and equipment development for textile dyeing in supercritical carbon dioxide

The large-scale water pollution by the textile dyeing industry is a global environmental problem. The ever more stringent regulations on wastewater also make it an economical problem. In the last two decades therefore, research has been done on an environmentally benign technology, using supercritical carbon dioxide (scCO2) as a dye solvent, rather than water. The applicability of the technology is limited at this moment by two factors. Firstly, there is not enough knowledge on reactive and non-reactive dyeing. Secondly, because the process operates at conditions of typically 120C and 300 bar, high-pressure equipment is needed which results in high investment costs that stand in the way of industrial implementation. In this work, the supercritical dyeing process was investigated experimentally regarding both reactive and non-reactive dyeing and also new equipment was designed to minimize the equipment and process costs.