Optimization of Heat Exchanger Network via Pinch Analysis in Heat Pump-Assisted Textile Industry Wastewater Heat Recovery System

Abstract

Reactive dyeing is primarily used in the textile industry to achieve a high level of productivity for high-quality products. This method requires heating a large amount of freshwater for dyeing and cooling for the biological treatment of discharged wastewater. If the heat of the wastewater discharged from the textile industry is recovered, energy used for heating freshwater and cooling wastewater can be significantly reduced. However, the energy efficiency of this industry remains low, owing to the limited use of waste heat. Hence, this study suggested a cost-optimal heat exchanger network (HEN) in a heat pump-assisted textile industry wastewater heat recovery system with maximizing energy efficiency simultaneously. A novel two-step approach was suggested to develop the optimal HEN in heat pump-assisted textile industry wastewater heat recovery system. In the first step, the system was designed to integrate the heat exchanger and heat pump to recover waste heat effectively. In the second step, the HEN in the newly developed system was retrofitted using super-targeted pinch analysis to minimize cost and maximize energy efficiency simultaneously. As a result, the proposed wastewater heat recovery system reduced the total annualized cost by up to 43.07% as compared to the conventional textile industry lacking a wastewater heat recovery system. These findings may facilitate economic and environmental improvements in the textile industry.

Statistical Analysis of Manufacturing, Trade and Service in the Textile Industry in Ecuador, 2000-2020

“…Telling the stories of Andean families of Pelileo, she traces their varied responses to historical pressures over three hundred years; the responses range from everyday acts to the historical transformation of culture through ethnogenesis. These stories of ordinary Andean men and women provide insight into the lived experience of the people who formed the backbone of Quito's textile industry (Kim et al, 2022). (Doyon-Bernard, 1993) Details are presented of the textile remains recovered from the shaft tombs of La Florida, near Quito in Ecuador, which provide an opportunity to evaluate the weaving tradition of pre-Hispanic Ecuador.…”

Advanced Design of Integrated Heat Recovery and Supply System Using Heated Water Storage for Textile Dyeing Process

“…Finally, cold rinsing, washing, hot rinsing, and finishing are performed in the after-treatment process. Table 1 lists the operating time, wastewater temperature, and mass flow rate for each step of the dyeing process [13] and the flow chart of the dyeing process is presented in Figure 1. To achieve the objective of this study, a waste heat recovery system consisting of one heat exchanger and one storage tank was suggested, as shown in Figure 2.…”

“…Interest rate [21] 7% Operating hours [7] 8000 h/yr Plant operating life [13] 5 years Steam cost [22] USD 1.16 × 10 −5 /kJ Annual maintenance cost [20] 3% of the total capital cost Table 10. Cost parameters for the economic analysis.…”

“…The results of the OPEX, additional CAPEX, and total cost are shown in Figure 7. To calculate the total OPEX, it was assumed that the process operated for five years [13]. The total costs were USD 5.13 million, USD 2.66 million, USD 1.89 million, and USD 2.05 million for base case, Case 1, Case 2, and Case 3, respectively.…”

“…As a result, the proposed trigeneration system provided 88 kW equivalent electrical power with an efficiency of 62% and required five years payback period. Kim et al [13] suggested a cost-optimal heat-exchange network. A heat pump was used to recover waste heat from the wastewater at temperatures below 30 • C; otherwise, the waste heat was recovered through the heat exchanger.…”