Search

[Display omitted] • Feasibility of using organic wastewater as renewable energy source is verified. • ＞99% COD, TOC removal rate in the experimental platform. • Up to 78.75% of the energy recovery efficiency of the SCWO system. The degradation of high concentration organic wastewater and the recovery of energy using supercritical water oxidation (SCWO) technology have the potential to become viable in the future. High concentration organic wastewater contains a significant amount of energy. This paper focuses on utilizing high concentrated wastewater as a renewable energy source, from an energy system perspective, an experimental rig was designed to determine the optimal working conditions. The experiments were conducted with an oxidation coefficient of 1.1, a flow rate of high concentration organic wastewater of 9 ml/min, a heating temperature of 400 °C, and a reaction pressure of 25 MPa. Under these conditions, the COD and TOC removal rates of the high concentration organic wastewater were found to be 99.383 % and 99.876 % respectively. Additionally, the phenomenon of "Abnormalities in pressure sensitivity" observed during high concentration organic wastewater the experiment was further explained through additional experiments. Finally, by comparing the experimental energy recovery with the simulation results, an energy recovery efficiency of 78.95 % was achieved. The feasibility of the simulated energy recovery in practice was verified, confirming the potential to convert the previous energy-consuming wastewater treatment process into a productive one. This study provides a theoretical and experimental foundation for further related research. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Proposed hybrid heat recovery system for efficient energy utilization of spray dryer. • Proposed new performance indicator to assess sustainability in heat recovery systems. • Developed rigorous mathematical model for direct and hybrid heat recovery systems. • Investigated optimal performance of spray dryer. • Compared proposed energy recovery schemes to find best configuration. Abstract Thermal dewatering using spray dryers is an energy-intensive process, which recently, applied for removal of water from industrial effluents by evaporation. Reduction of energy consumption is vital to reduce operating cost in addition to sustainable development. In this paper, the modern integrated energy savings scheme is proposed in four parts. (i) An advanced energy saving configuration named as a hybrid heat recovery system for a spray dryer, (ii) Developed rigorous but simple mathematical model for direct and hybrid heat recovery system, (iii) A generalized performance indicator for investigation of environmental impact on energy recovery called as 'Sustainability Index' is proposed for thermal systems and demonstrated for spray dryer, and finally (iv) The proposed methods are explained with the help of an illustrative example taken from the literature. Up to 80% recirculation ratio, performance enhancement, and Sustainability Index are significantly higher for the hybrid heat recovery system than the direct heat recovery system, while for higher than 80% recirculation ratio, both are approaching towards nearly same value. Furthermore, with increasing recirculation ratio, moisture recirculation into the drying chamber also increases, which reduces the requirement of the mass flow rate of dry hot air due to the higher heat capacity of recirculated moisture. A reduction in hot air requirement reduces the high-grade blower power in addition to net heat supplied. Dryer efficiency and sustainability index, both show a strong dependency on the amount of heat recovery for spray dryer. [ABSTRACT FROM AUTHOR]