Energy model-based benchmarking of the drying process in the stenter machine

Abstract

Stenter machines are used widely in textile dyeing and printing houses for drying and heat setting of fabric. This is one of the most thermal energy-consuming equipment in the textile process. In this paper, the advanced energy model of the stenter machine is developed using primary mass and energy balance equations for ideal conditions as well as standard operating conditions, accounting for various energy losses to understand energy flow. To find out the scope for reduction in energy consumption, energy benchmarking is very important; compared with it, the appropriate energy consumption of a plant can be checked and changed. Furthermore, to eliminate problems such as life, process conditions, and quality of dyeing and printing houses considered during the study, unlike statistical energy benchmarking, in this paper, energy model-based benchmarking is proposed and applied for literature problems. Based on the data given in the literature for conveyor belt, stenter 1 and stenter 2, the specific energy consumption (SEC) for cotton is 4889, 3586, and 4304 kJ/kg of water evaporation, respectively, which is lower than the polywool fabric, having 5185 kJ/kg of water evaporation for another stenter machine. The energy efficiency index (EEI) of conveyor belt dryer, stenter 1, and stenter 2 are 1.56,1.18 and 1.34 for cotton, respectively, and for polywool with another stenter it is 1.92, indicating the polywool process is not energy efficient even polywool do not have bound moisture. Further, Energy flow analysis is carried out for the given stenter and fabric drying process, indicating the highest losses are in the exhaust process even after direct heat recovery by partial recirculation of exhaust gases. By analyzing the energy consumption of stenter machines through energy model based benchmarking and energy efficiency index presents the condition of process and machine from an energy perspective, and energy flow model gives the scope of the energy-saving potential. By using the developed model, the effect of change in atmospheric air temperature and humidity ratio due to season and geographic location on the performance of the stenter machine is investigated and found that there is a variation in performance up to 10% of the total energy required.

Keywords:

• Energy analysis
• benchmarking
• energy model
• energy efficiency index (EEI)
• stenter
• the fabric drying process

Acknowledgment

Authors are thankful for partial funding of current work to the Ministry of Textile, Government of India, New Delhi, India.