Advanced energy recovery systems design of stenter processes: Energy, exergy and Techno-economic analyses

Stenters used for drying during the dyeing process, waste considerable thermal energy through exhaust gas. This energy waste is one of the major bottlenecks to improving the sustainability of the textile dyeing field. To find the most efficient recovery of the waste heat from the stenters for supplying various energy sources and reducing energy consumption within overall textile system, this study compares three heat recovery systems: (Case- 1) air preheating, (Case-2) hot-water generation, and (Case-3) power generation. Energy, exergy, and economic analyses indicated that all cases demonstrated superior results those obtained using the base case. In terms of energy consumption, Case-1 demonstrated a 60.8 % reduction achieved through decreased fuel consumption. In particular, the economic analysis indicated that Case-1 was the most favorable option because it possesses the lowest operating costs by significantly reducing fuel consumption for air preheating. Additionally, the simple configuration of the process and the use of a small heat exchanger contribute to a lower capital cost. Thus, Case-1 could the most efficiently recover and utilize the heat wasted from the stenter at a relatively low investment cost among proposed systems. This demonstrated the potential for energy and cost savings within the textile industry.