Review on Water and Energy Integration in Process Industry: Water-Heat Nexus

Abstract

The improvement of water and energy use is an important concern in the scope of improving the overall performance of industrial process plants. The investment in energy efficiency comprehended by the most recent sustainability policies may prove to be an effective response to the fall of energy intensity rates associated with the economic crisis brought by the COVID-19 pandemic. The improvement in water efficiency may also prove to be a potential approach due to its interdependencies to energy use, whose exploitation comprises part of the study of the water-energy nexus. Waste heat recovery and water reclamation practices have been exploited to improve water and energy efficiency. A specific method designated “Combined Water and Energy Integration” has been applied to water recycling as both an additional water source and a heat recovery source in a set of water-using processes. In scientific and industrial domains, there is still a need for integrated approaches of water-using and combustion-based processes for overall water and energy efficiency improvements in industrial plants. In this work, an innovative approach for a simultaneous improvement of water and energy use is proposed based on process integration and system retrofitting principles. This proposal is based on the delineation of two innovative concepts: Water and Energy Integration Systems (WEIS) and Water-Heat Nexus (WHN). A review on existing technologies for waste heat recovery, thermal energy storage and heat-driven wastewater treatment is performed, following a conceptualisation design.

Assessing the Progress toward a Water-Efficient Economy in the United States from 1985 to 2015

“…The improvements of state-level WUEs, especially WUE-Ts and WUE-Is, were primarily related to WW pc declines from 1985 to 2015. This is consistent with the wide investment in and implementation of water-saving infrastructure and practices in industrial facilities. , The largest industrial water users in the US are thermoelectric power plants that extract both fresh and saline water (with freshwater constituting the majority) for cooling purposes, which accounted for 41% of national total water withdrawals in 2015. From 2010 to 2015, the cooling water withdrawal decreased by 18%, owing to a shift from once-through to recirculating cooling, enhanced aquatic life protections, and power plant closures. ,, Moreover, both GVA pc growths and WW pc declines played a crucial role in state-level WUE-S improvement.…”

Energy Efficiency Management in Small and Medium-Sized Enterprises: Current Situation, Case Studies and Best Practices

“…Compared with simpler measures, extensive changes are always associated with high (investment) cost and the corresponding high business/financial risk. Such changes might include the implementation of appropriate CHP plants, the redesign of production lines and/or procedures, the application of sophisticated prediction, simulation, and control techniques, and the connection of the facility to the local heating or cooling network to channel waste energy or heat [76,77].…”

Sustainability and Strategic Assessment of Water and Energy Integration Systems: Case Studies of the Process Industry in Portugal

“…While, for the former issue, the promotion of energy efficiency improvement measures allied to renewable energy and alternative fuel integration have been regarded as keys to solving it, for the latter, the promotion of improved water management techniques in end-use sectors has been similarly identified as a solving method. The concept of WEIS (as introduced in previous works by the authors [17]) promotes the reduction of the consumption of both energy and water while simultaneously approaching the development of methods for the solving of the two aforementioned issues.…”

“…This concept deals with all of the potential interdependencies between the use of water and energy resources, for which their exploitation must be performed so as to bring an overall compromise between economic viability, environmental burden reduction, and social stability so as to promote the sustainable character of physical systems [16]. A specific application of the water-energy nexus has most recently been proposed by the definition of the concept of Water and Energy Integration Systems (WEIS) [17,18]. These are systems that encompass a set of combustion-based processes and a set of water-using processes, as well as the installation of several types of technologies, which, from a holistic perspective, bring benefits at the level of the reduction of overall water and energy inputs and gas and solid contaminant discharges.…”

“…A conjoint effort led by researchers in Portugal (namely, from ISQ-Instituto de Soldadura e Qualidade e Instituto Superior Técnico) has been dedicated to the study of the potential to install the mentioned types of systems and improvement measures in the context of the development of engineering projects for single industrial plants [17], assisted by the use of simulation and optimisation tools-namely, the specialised Modelica-and Python-languages-based ThermWatt [18]. Although these models have been successful with respect to the estimation of the economic and environmental impact reduction potential associated with WEIS, a systemisation of the compliance of this type of complex engineering project with the specific sustainability and strategic aims may be developed, with the ultimate purpose of assisting the end-use sector stakeholders in the selection of the most favourable projects (thus facilitating the commissioning of these projects as well as the technology readiness levels associated with some technologies).…”