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

Abstract

Heat recovery from a high-temperature wastewater is the major concern in the conventional textile industry. However, limited space in the textile plant is an important constraint for the process enhancement. Therefore, an easily applicable heat recovery system with a small amount of additional equipment to the existing dyeing process is required. To meet the needs from the industry, this study suggests an integrated heat recovery and supply system consisting of single heat exchanger and single storage tank using freshwater as a thermal carrier to utilize the reusable heat in the wastewater. Freshwater is stored in a tank after direct heat exchange with wastewater and is supplied to the next dyeing process. Three different designs of the integrated system were compared based on the lower limit of the wastewater temperature: above 50 °C, 40 °C, and 30 °C for Cases 1, 2, and 3, respectively. The energy and energy flow analyses showed Case 2 to be well balanced between the quality and quantity of the recovered heat, and there was no heat loss via drainage. The heat demand for Case 2 was 795.5 kW, which was the lowest among all cases. Furthermore, an economic analysis showed that the total cost for Case 2 was reduced by 63.2% compared with the base case. Despite the use of an additional heat exchanger and water storage tank, the proposed system was more economical because of the reduced operating costs. Finally, a detailed analysis was conducted by determining the more efficient temperature for heat recovery and supply.

Opportunities and Challenges for Research on Heat Recovery from Wastewater: Bibliometric and Strategic Analyses

“…The countries with the highest number of publications were China (318), the United States (47), Turkey (44), the United Kingdom (44), and Sweden (43). In Europe, apart from the previously mentioned countries, other countries with a significant number of publications were Austria (39), Poland (32), France (31), and Switzerland (27). Asian countries, excluding previously mentioned China, showed lower interest in the topic of heat recovery from wastewater.…”

“…This issue is particularly relevant when dealing with industrial wastewater. Hence, from the perspective of eliminating potential failures and ensuring proper operation of the heat recovery system, it is essential to adapt the technological setup of the HPs system to the type and quality of wastewater [32].…”

“…Despite the potential requirement for expensive technology and infrastructure, current research [140,151] showed that the long-term financial benefits associated with energy savings in industrial facilities confirm the legitimacy of using heat recovery systems from industrial wastewater [32]. According to Etemoglu [152], reusing waste heat will become one of the most crucial actions for energy generation in the industry in the near future.…”

“…Seo et al [32] The efficiency research of three design variants of a high temperature wastewater heat recovery system in the textile industry, consisting of a heat exchanger and a water tank; the three analyzed configurations of the integrated heat recovery system were developed based on the lower temperature limit of the wastewater…”

“…All these solutions are often referred to as drain water heat recovery (DWHR) units. There are also solutions in which special wastewater heat exchanger designs are used to preheat ventilation air [31] or are used to recover heat from industrial wastewater [32]. The possibility of using HPs is considered when there is a larger amount of available wastewater.…”